PHILLIPS v. AWH CORP. 1303 - Berkeley Law States Court of Appeals, Federal Circuit. July 12, 2005. Background: Owner of patent for vandal-ism-resistant wall panels sued former dis-tributor

1303PHILLIPS v. AWH CORP.Cite as 415 F.3d 1303 (Fed. Cir. 2005)

1994), in summarily dismissing Applicant’sInternet advertising evidence is misplaced.Leatherman was decided long before In-ternet advertising became a cost-effectivealternative to traditional advertising me-dia, and its relevance to the facts of thepresent case is questionable.

The Board also failed to address evi-dence that Applicant’s sales rose quicklyas a result of its advertising. In 2001,cumulative sales rose from $500,000, forthe first four months of the mark’s use, to$4,500,000 over the next seven months.The company was featured prominently inthe trade press for its innovative services.Because the Board did not discuss thisevidence, we are left with no basis to de-termine whether the Board considered thisevidence in determining the extent towhich Applicant might have leveraged theInternet and its mark’s domain-name sta-tus to acquire secondary meaning, evenwith only modest advertising expenditures.

For the reasons articulated, I believethe Board committed legal error in weigh-ing the evidence and acted arbitrarily innot considering evidence. These errorshad a ‘‘bearing on TTT the substance of thedecision reached’’ by the Board. See In reWatts, 354 F.3d 1362, 1370 (Fed.Cir.2004)(internal quotations omitted). Therefore, Iwould vacate the Board’s determination ofno acquired distinctiveness and remand forreconsideration consistent with this opin-ion.

,

Edward H. PHILLIPS, Plaintiff–Appellant,

v.

AWH CORPORATION, HopemanBrothers, Inc., and Lofton Corpora-tion, Defendants–Cross Appellants.

Nos. 03–1269, 03–1286.

United States Court of Appeals,Federal Circuit.

July 12, 2005.

Background: Owner of patent for vandal-ism-resistant wall panels sued former dis-tributor for infringement. The UnitedStates District Court for the District ofColorado, Marcia S. Krieger, J., grantedsummary judgment for former distributor,and owner appealed. The Court of Ap-peals, 363 F.3d 1207, affirmed.

Holding: On rehearing en banc, the Courtof Appeals, Bryson, Circuit Judge, heldthat ‘‘baffles,’’ called for in asserted claim,were not limited to non-perpendicular, pro-jectile-deflecting structures disclosed inpreferred embodiment.

Affirmed in part, reversed in part, dis-missed in part, and remanded.

Lourie, Circuit Judge, concurred in part,dissenting in part, and filed opinion inwhich Pauline Newman, Circuit Judge,joined.

Mayer, Circuit Judge, dissented and filedopinion in which Pauline Newman, CircuitJudge, joined.

1. Patents O101(8)Limitation in patent claim for vandal-

ism-resistant wall, calling for ‘‘means dis-posed inside shell for increasing its loadbearing capacity’’ comprising ‘‘internalsteel baffles’’ extending inwardly fromsteel shell walls, recited sufficient struc-ture to avoid means-plus-function treat-ment. 35 U.S.C.A. § 112, par. 6.

1304 415 FEDERAL REPORTER, 3d SERIES

2. Patents O165(2)

It is bedrock principle of patent lawthat claims of patent define invention towhich patentee is entitled the right to ex-clude.

3. Patents O157(1), 161

Words of patent claim are generallygiven their ordinary and customary mean-ing, i.e., meaning that term would have toperson of ordinary skill in the art in ques-tion on effective filing date of patent appli-cation.

4. Patents O161, 167(1)

Person of ordinary skill in the art,through whose eyes patent claim is con-strued, is deemed to read claim term notonly in context of particular claim in whichdisputed term appears, but in context ofentire patent, including specification.

5. Patents O165(5)

Because claim terms are normallyused consistently throughout patent, usageof term in one claim can often illuminatemeaning of same term in other claims.

6. Patents O165(5)

Presence of dependent patent claimthat adds particular limitation gives rise topresumption that limitation in question isnot present in independent claim.

7. Patents O101(4)

Patent claims must be read in view ofspecification, of which they are part.

8. Patents O167(1)

Patent specification is always highlyrelevant to claim construction analysis; itis single best guide to meaning of disputedterm, and is usually dispositive.

9. Patents O162, 167(1.1)

When patent specification reveals spe-cial definition given to claim term by pat-entee that differs from meaning it would

otherwise possess, inventor’s lexicographygoverns.

10. Patents O167(1.1)Where patent specification reveals in-

tentional disclaimer, or disavowal, of claimscope by inventor, such revealed intentionis dispositive.

11. Patents O168(1)‘‘Prosecution history’’ consists of com-

plete record of proceedings before Patentand Trademark Office and includes priorart cited during examination of patent.

See publication Words and Phras-es for other judicial constructionsand definitions.

12. Patents O168(2.1)Prosecution history can often inform

meaning of patent claim language by dem-onstrating how inventor understood inven-tion and whether inventor limited inven-tion in course of prosecution, making claimscope narrower than it would otherwise be.

13. Patents O159Although extrinsic evidence can shed

useful light on relevant art, it is less signif-icant than intrinsic record in determininglegally operative meaning of patent claimlanguage.

14. Patents O159Dictionaries, though extrinsic evi-

dence, are among tools that can assistpatent-construing court in determiningmeaning of particular terminology to thoseof skill in the art of invention.

15. Patents O159Extrinsic evidence in form of expert

testimony can be useful to patent-constru-ing court for variety of purposes, such asto provide background on technology atissue, to explain how invention works, toensure that court’s understanding of tech-nical aspects of patent is consistent withthat of person of skill in the art, or to


establish that particular term in patent orprior art has particular meaning in perti-nent field.

16. Patents O159

Conclusory, unsupported assertionsby experts as to definition of patent claimterm are not useful to construing court.

17. Patents O159

Court, when construing patent, shoulddiscount any expert testimony that isclearly at odds with claim constructionmandated by claims themselves, writtendescription, and prosecution history.

18. Patents O159

Extrinsic evidence may be useful toconstruing court, but it is unlikely to resultin reliable interpretation of patent claimscope unless considered in context of in-trinsic evidence.

19. Patents O159

It is permissible for patent-construingcourt, in its sound discretion, to admit anduse extrinsic evidence; such evidence canhelp educate court regarding field of in-vention and can help court determine whatperson of ordinary skill in the art wouldunderstand claim terms to mean.

20. Patents O159

Although dictionaries or comparablesources are often useful to assist in under-standing commonly understood meaning ofpatent claim terms, construing court’s fo-cus remains on understanding how personof ordinary skill in the art would under-stand claim terms.

21. Patents O157(1)

There is no magic formula or cate-chism for conducting patent claim con-struction; court is not barred from consid-ering any particular sources or required toanalyze sources in any specific sequence,so long as those sources are not used to

contradict claim meaning that is unambig-uous in light of intrinsic evidence.

22. Patents O101(3)

Internal steel ‘‘baffles,’’ called for inpatent for vandalism-resistant wall panels,were not limited to non-perpendicular, pro-jectile-deflecting structures disclosed inpreferred embodiment; specification didnot require that internal structures alwaysbe capable of performing that function.

23. Patents O101(3)

Fact that patent asserts that inventionachieves several objectives does not re-quire that each claim be construed as lim-ited to structures that are capable ofachieving all those objectives.

24. Patents O157(2)

Application of patent constructionmaxim, that claims should be so construed,if possible, as to sustain their validity, islimited to cases in which court concludes,after applying all available tools of claimconstruction, that claim is still ambiguous.

Patents O328(2)

4,677,798. Construed.

Carl F. Manthei, Attorney at Law, ofBoulder, Colorado, argued for plaintiff-ap-pellant.

Mark W. Fischer, Faegre & BensonLLP, of Boulder, Colorado, argued for de-fendants-cross appellants. With him onthe brief were Neal S. Cohen and Peter J.Kinsella. Of counsel on the brief wereMaurice M. Klee, Law Office of MauriceM. Klee, Ph.D., Fairfield, Connecticut, andKenneth C. Bass, III, Sterne, Kessler,Goldstein & Fox, of Washington, DC. Ofcounsel was Scott E. Holwick, Faegre &Benson LLP.


John M. Whealan, Solicitor, UnitedStates Patent and Trademark Office, ofAlexandria, Virginia, argued for amicuscuriae United States. With him on thebrief were James A. Toupin, GeneralCounsel; Cynthia C. Lynch; Linda Mon-cys Isacson; and Thomas W. Krause, As-sociate Solicitors. Of counsel on the briefwere Peter D. Keisler, Assistant AttorneyGeneral; John J. Fargo, Director, Com-mercial Litigation Branch, and AnthonyJ. Steinmeyer, Attorney, Appellate Staff,Civil Division, United States Departmentof Justice, of Washington, DC; and Wil-liam E. Kovacic, General Counsel, andSuzanne T. Michel, Chief Counsel for In-tellectual Property, Federal Trade Com-mission, of Washington, DC.

Robert L. Baechtold, Fitzpatrick, Cella,Harper & Scinto, of New York, New York,for amici curiae Novartis PharmaceuticalsCorporation, et al. With him on the briefwere Nicholas N. Kallas, Stevan J. Bosses,and Brian V. Slater.

Paul H. Berghoff, McDonnell BoehnenHulbert & Berghoff LLP, of Chicago, Illi-nois, for amicus curiae Intellectual Proper-ty Owners Association. With him on thebrief was Joshua R. Rich. Of counsel onthe brief was J. Jeffery Hawley, President,Intellectual Property Owners Association,of Washington, DC. Of counsel was Her-bert C. Wamsley, Intellectual PropertyOwners Association.

Charles W. Bradley, Rader, Fishman &Grauer, PLLC, of Bloomfield Hills, Michi-gan, for amicus curiae Charles W. Bradley.

Henry C. Bunsow, Howrey Simon Ar-nold & White, LLP, of San Francisco,California, for amicus curiae AD HOCCommittee of Patent Owners in the Wire-less Industry. With him on the brief wereRobert C. Laurenson and David W. Long.Of counsel on the brief were Robert D.Yeager, Thomas J. Edgington, and Mark

G. Knedeisen, Kirkpatrick & LockhartLLP, of Pittsburgh, Pennsylvania.

Alexander C. Johnson, Jr., Marger,Johnson & McCollom, P.C., of Portland,Oregon, for amicus curiae Oregon PatentLaw Association.

Alice A. Kipel, Steptoe & Johnson, LLP,of Washington, DC, for amicus curiae In-ternational Trade Commission Trial Law-yers Association.

Stephen P. McNamara, St. Onge Stew-ard Johnston & Reens LLC, of Stamford,Connecticut, for amicus curiae ConnecticutIntellectual Property Law Association.With him on the brief was Richard J.Basile. Of counsel on the brief were Wil-liam J. Sapone, Coleman Sudol Sapone,P.C., of Bridgeport, Connecticut, MichaelJ. Rye, Cantor Colburn LLP, of Bloom-field, Connecticut.

Douglas E. Olson, Paul, Hastings, Janof-sky & Walker, LLP, of San Diego, Califor-nia, for amicus curiae San Diego Intellec-tual Property Law Association. With himon the brief were Kurt M. Kjelland, JohnE. Peterson, and April M. Alex. Of counselon the brief were Ned A. Israelsen,Knobbe Martens Olson & Bear, LLP, ofSan Diego, California, and William L. Res-pess, Nanogen, Inc., of San Diego, Califor-nia.

John Will Ongman, Barnes & ThornburgLLP, of Washington, DC, for amicus curi-ae Biotechnology Industry Organization.With him on the brief was Alice O. Martin,of Chicago, Illinois. Of counsel on thebrief was Stephan E. Lawton, Vice Presi-dent and General Counsel, BiotechnologyIndustry Organization, of Washington, DC.

Steve Z. Szczepanski, Kelley Drye &Warren LLP, of Chicago, Illinois, for ami-cus curiae Parus Holdings, Inc. With himon the brief was Mary Jo Boldingh.


Frederick A. Tecce, McShea Tecce, P.C.,of Philadelphia, Pennsylvania, for amici cu-riae McShea Tecce, P.C., et al.

Michael P. Dougherty, Morgan & Finne-gan, L.L.P., of New York, New York, foramicus curiae Federal Circuit Bar Associa-tion. Of counsel on the brief was CharlesF. Schill, President, Federal Circuit BarAssociation, of Washington, DC.

Edward D. Manzo, Cook, Alex, McFar-ron, Manzo, Cummings & Mehler, Ltd., ofChicago, Illinois, for amicus curiae TheIntellectual Property Law Association ofChicago. Of counsel with him on the briefwere Patrick G. Burns, Greer, Burns &Crain, Ltd., of Chicago, Illinois, Dean A.Monco, Wood, Phillips, Katz, Clark & Mor-timer, of Chicago, Illinois, Bradford P.Lyerla, Marshall, Gerstein & Borun, ofChicago, Illinois, and Timothy J. Vezeau,Katten Muchin Zavis Rosenman, of Chica-go, Illinois.

Maxim H. Waldbaum, Schiff HardinLLP, of New York, New York, for amicuscuriae Federation Internationale Des Con-seils En Propriete Industrielle. Of coun-sel on the brief was John P. Sutton, of SanFrancisco, California.

Michael R. Dzwonczyk, Sughrue Mion,PLLC, of Washington, DC, for amicus cu-riae Sughrue Mion, PLLC. With him onthe brief were Frank L. Bernstein ofMountain View, California, and BrandonM. White of Washington, DC.

Sharon A. Israel, Jenkens & Gilchrist,P.C., of Houston, Texas, for amicus curiaeHouston Intellectual Property Law Associ-ation. Of counsel on the brief were Jere-my P. Welch, Jonathan M. Pierce, andJeffrey L. Johnson, Conley Rose, P.C., ofHouston, Texas.

George C. Summerfield, Jr., Stadheim &Grear, of Chicago, Illinois, for amici curiaeThe Wisconsin Alumni Research Founda-

tion, et al. With him on the brief wereJoseph A. Grear and Keith A. Vogt.

Bruce M. Wexler, Fitzpatrick, Cella,Harper & Scinto, of New York, New York,for amicus curiae New York IntellectualProperty Law Association. With him onthe brief were Matthew S. Seidner andJohn D. Murnane.

Rick D. Nydegger, Workman Nydegger,of Salt Lake City, Utah, for amicus curiaeAmerican Intellectual Property Law Asso-ciation. With him on the brief was DavidR. Todd. Of counsel on the brief wereDenise W. DeFranco, Foley Hoag LLP, ofBoston, Massachusetts, and Joseph R. Reand Joseph S. Cianfrani, Knobbe MartensOlson & Bear, of Irvine, California.

Christopher Landau, Kirkland & EllisLLP, of Washington, DC, for amicus curi-ae Infineon Technologies North AmericaCorp. With him on the brief were John C.O’Quinn, of Washington, DC, and John M.Desmarais, Gregory S. Arovas, and Mi-chael P. Stadnick, of New York, NewYork.

Mark I. Levy, Kilpatrick Stockton, LLP,of Washington, DC, for amicus curiae As-sociation of Corporate Counsel. With himon the brief were Anthony B. Askew andEugene B. Joswick, of Atlanta, Georgia.Of counsel on the brief were Frederick J.Krebs and Susan Hackett of Washington,DC, Nelson A. Blish, Eastman Kodak, ofRochester, New York, John W. Hogan, Jr.,Wyeth, of Madison, New Jersey, and Tara-neh Maghame, Hewlett Packard, of Cuper-tino, California.

Mark A. Lemley, Keker & VanNest,LLP, of San Francisco, California, for ami-ci curiae Intel Corporation, et al. Withhim on the brief were Brian L. Ferrall andRyan M. Kent.

Erik Paul Belt, Bromberg and SunsteinLLP, of Boston, Massachusetts, for amicuscuriae Boston Patent Law Association. Of


counsel on the brief was Peter Corless,Edwards and Angell LLP, of Boston, Mas-sachusetts.

Susan M. Dadio, Burns, Doane, Swecker& Mathis, L.L.P., of Alexandria, Virginia,for amicus curiae Bar Association of theDistrict of Columbia—Patent, Trademark& Copyright Section. Of counsel on thebrief was Lynn E. Eccleston, The Eccle-ston Law Firm, of Washington, DC.

W. Thomas McGough, Jr., Reed SmithLLP, of Pittsburgh, Pennsylvania, for ami-cus curiae Medrad, Inc. With him on thebrief were Frederick H. Colen and BarryJ. Coyne. Of counsel on the brief wasGregory L. Bradley, Medrad, Inc., of Indi-anola, Pennsylvania.

Peter A. Sullivan, Hughes Hubbard &Reed LLP, of New York, New York, foramicus curiae The Association of the Barof the City of New York. Of counsel on thebrief was Catriona M. Collins, Cowan, Lie-bowitz & Latman, P.C., of New York, NewYork.

Anthony R. Zeuli, Merchant & GouldP.C., of Minneapolis, Minnesota, for ami-cus curiae Association of Patent LawFirms. With him on the brief were Thom-as J. Leach, III and Rachel Clark–Hu-ghey. Of counsel on the brief were ScottP. McBride and Christopher R. Carroll,McAndrews, Held & Malloy Ltd., of Chica-go, Illinois, and Eric R. Moran, McDonnell,Boehnen, Hulbert & Berghoff LLP, ofChicago, Illinois.

Daniel B. Ravicher, Public Patent Foun-dation, of New York, New York, for ami-cus curiae Public Patent Foundation.

Theodore T. Herhold, Townsend andTownsend and Crew LLP, of Palo Alto,California, for amici curiae VISA U.S.A.Inc., et al. With him on the brief wereDaniel J. Furniss, Susan M. Spaeth, Madi-son C. Jellins, and Mark G. Sandbaken.

Mark A. Goldstein, SoCal IP LawGroup, of Westlake Village, California, foramicus curiae Conejo Valley Bar Associa-tion. With him on the brief were StevenC. Sereboff and Joel G. Landau.

Robert J. Grey, Jr., President, AmericanBar Association, of Chicago, Illinois, foramicus curiae American Bar Association.With him on the brief was William L.LaFuze. Of counsel on the brief wereDonald R. Dunner and Richard L. Rainey,Finnegan, Henderson, Farabow, Garrett &Dunner, L.L.P., of Washington, DC.

R. Polk Wagner, University of Pennsyl-vania Law School, of Philadelphia, Penn-sylvania, for amicus curiae Patent LawProfessors R. Polk Wagner, et al.

Joshua D. Sarnoff, Washington Collegeof Law, American University, of Washing-ton, DC, for amici curiae Consumers Un-ion, et al.

Laura M. Slenzak, Siemens Corporation,of Auburn Hills, Michigan, for amicus curi-ae The State Bar of Michigan, IntellectualProperty Law Section, joined in the briefof the New York Intellectual PropertyLaw Association.

Lea Hall Speed, Baker, Donelson, Bear-man & Caldwell, of Memphis, Tennessee,for amicus curiae Tennessee Bar Associa-tion, joined in the brief of the New YorkIntellectual Property Law Association.

Before MICHEL, Chief Judge,NEWMAN, MAYER, LOURIE,CLEVENGER, RADER, SCHALL,BRYSON, GAJARSA, LINN, DYK, andPROST, Circuit Judges.

Opinion for the court filed by CircuitJudge BRYSON, in which Chief JudgeMICHEL and Circuit JudgesCLEVENGER, RADER, SCHALL,GAJARSA, LINN, DYK, and PROST join;and in which Circuit Judge LOURIE joinswith respect to parts I, II, III, V, and VI;


and in which Circuit Judge PAULINENEWMAN joins with respect to parts I,II, III, and V. Opinion concurring in partand dissenting in part filed by CircuitJudge LOURIE, in which Circuit JudgePAULINE NEWMAN joins. Dissentingopinion filed by Circuit Judge MAYER, inwhich Circuit Judge PAULINENEWMAN joins.

BRYSON, Circuit Judge.

Edward H. Phillips invented modular,steel-shell panels that can be welded to-gether to form vandalism-resistant walls.The panels are especially useful in buildingprisons because they are load-bearing andimpact-resistant, while also insulatingagainst fire and noise. Mr. Phillips ob-tained a patent on the invention, U.S. Pat-ent No. 4,677,798 (‘‘the ’798 patent’’), andhe subsequently entered into an arrange-ment with AWH Corporation, HopemanBrothers, Inc., and Lofton Corporation(collectively ‘‘AWH’’) to market and sellthe panels. That arrangement ended in1990. In 1991, however, Mr. Phillips re-ceived a sales brochure from AWH thatsuggested to him that AWH was continu-ing to use his trade secrets and patentedtechnology without his consent. In a ser-ies of letters in 1991 and 1992, Mr. Phillipsaccused AWH of patent infringement andtrade secret misappropriation. Corre-spondence between the parties regardingthe matter ceased after that time.

In February 1997, Mr. Phillips broughtsuit in the United States District Court forthe District of Colorado charging AWHwith misappropriation of trade secrets andinfringement of claims 1, 21, 22, 24, 25, and26 of the ’798 patent. Phillips v. AWHCorp., No. 97–N–212 (D.Colo.). The dis-trict court dismissed the trade secret mis-appropriation claim as barred by Colora-do’s three-year statute of limitations.

With regard to the patent infringementissue, the district court focused on thelanguage of claim 1, which recites ‘‘further

means disposed inside the shell for in-creasing its load bearing capacity compris-ing internal steel baffles extending inward-ly from the steel shell walls.’’ The courtinterpreted that language as ‘‘a means TTT

for performing a specified function,’’ sub-ject to 35 U.S.C. § 112, paragraph 6, whichprovides that such a claim ‘‘shall be con-strued to cover the corresponding struc-ture, material, or acts described in thespecification and equivalents thereof.’’Looking to the specification of the ’798patent, the court noted that ‘‘every textualreference in the Specification and its dia-grams show baffle deployment at an angleother than 90 to the wall faces’’ and that‘‘placement of the baffles at such anglescreates an intermediate interlocking, butnot solid, internal barrier.’’ The districtcourt therefore ruled that, for purposes ofthe ’798 patent, a baffle must ‘‘extend in-ward from the steel shell walls at an ob-lique or acute angle to the wall face’’ andmust form part of an interlocking barrierin the interior of the wall module. Be-cause Mr. Phillips could not prove in-fringement under that claim construction,the district court granted summary judg-ment of noninfringement.

Mr. Phillips appealed with respect toboth the trade secret and patent infringe-ment claims. A panel of this court af-firmed on both issues. Phillips v. AWHCorp., 363 F.3d 1207 (Fed.Cir.2004). As tothe trade secret claim, the panel unani-mously upheld the district court’s rulingthat the claim was barred by the applica-ble statute of limitations. Id. at 1215. Asto the patent infringement claims, the pan-el was divided. The majority sustainedthe district court’s summary judgment ofnoninfringement, although on differentgrounds. The dissenting judge wouldhave reversed the summary judgment ofnoninfringement.


The panel first determined that becausethe asserted claims of the ’798 patent con-tain a sufficient recitation of structure, thedistrict court erred by construing the term‘‘baffles’’ to invoke the ‘‘means-plus-func-tion’’ claim format authorized by section112, paragraph 6. Id. at 1212. Nonethe-less, the panel concluded that the patentuses the term ‘‘baffles’’ in a restrictivemanner. Based on the patent’s writtendescription, the panel held that the claimterm ‘‘baffles’’ excludes structures that ex-tend at a 90 degree angle from the walls.The panel noted that the specification re-peatedly refers to the ability of theclaimed baffles to deflect projectiles andthat it describes the baffles as being ‘‘dis-posed at such angles that bullets whichmight penetrate the outer steel panels aredeflected.’’ ’798 patent, col. 2, ll. 13–15; seealso id. at col. 5, ll. 17–19 (baffles are‘‘disposed at angles which tend to deflectthe bullets’’). In addition, the panel ob-served that nowhere in the patent is thereany disclosure of a baffle projecting fromthe wall at a right angle and that bafflesoriented at 90 degrees to the wall werefound in the prior art. Based on ‘‘thespecification’s explicit descriptions,’’ thepanel concluded ‘‘that the patentee regard-ed his invention as panels providing impactor projectile resistance and that the bafflesmust be oriented at angles other than 90 .’’Phillips, 363 F.3d at 1213. The paneladded that the patent specification ‘‘is in-tended to support and inform the claims,and here it makes it unmistakably clearthat the invention involves baffles angledat other than 90 .’’ Id. at 1214. The paneltherefore upheld the district court’s sum-mary judgment of noninfringement.

The dissenting judge argued that thepanel had improperly limited the claims tothe particular embodiment of the inventiondisclosed in the specification, rather thanadopting the ‘‘plain meaning’’ of the term‘‘baffles.’’ The dissenting judge noted that

the parties had stipulated that ‘‘baffles’’are a ‘‘means for obstructing, impeding, orchecking the flow of something,’’ and thatthe panel majority had agreed that theordinary meaning of baffles is ‘‘somethingfor deflecting, checking, or otherwise regu-lating flow.’’ Phillips, 363 F.3d at 1216–17. In the dissent’s view, nothing in thespecification redefined the term ‘‘baffles’’or constituted a disclaimer specifically lim-iting the term to less than the full scope ofits ordinary meaning. Instead, the dis-senting judge contended, the specification‘‘merely identifies impact resistance as oneof several objectives of the invention.’’ Id.at 1217. In sum, the dissent concludedthat ‘‘there is no reason to supplement theplain meaning of the claim language with alimitation from the preferred embodi-ment.’’ Id. at 1218. Consequently, thedissenting judge argued that the courtshould have adopted the general purposedictionary definition of the term baffle, i.e.,‘‘something for deflecting, checking, orotherwise regulating flow,’’ id., and there-fore should have reversed the summaryjudgment of noninfringement.

This court agreed to rehear the appealen banc and vacated the judgment of thepanel. Phillips v. AWH Corp., 376 F.3d1382 (Fed.Cir.2004). We now affirm theportion of the district court’s judgmentaddressed to the trade secret misappropri-ation claims. However, we reverse theportion of the court’s judgment addressedto the issue of infringement.

I

Claim 1 of the ’798 patent is representa-tive of the asserted claims with respect tothe use of the term ‘‘baffles.’’ It recites:

Building modules adapted to fit togetherfor construction of fire, sound and im-pact resistant security barriers androoms for use in securing records and


persons, comprising in combination, anouter shell TTT, sealant means TTT andfurther means disposed inside the shellfor increasing its load bearing capacitycomprising internal steel baffles extend-ing inwardly from the steel shell walls.

[1] As a preliminary matter, we agreewith the panel that the term ‘‘baffles’’ isnot means-plus-function language that in-vokes 35 U.S.C. § 112, paragraph 6. To besure, the claim refers to ‘‘means disposedinside the shell for increasing its load bear-ing capacity,’’ a formulation that wouldordinarily be regarded as invoking themeans-plus-function claim format. How-ever, the claim specifically identifies ‘‘in-ternal steel baffles’’ as structure that per-forms the recited function of increasingthe shell’s load-bearing capacity. In con-trast to the ‘‘load bearing means’’ limita-tion, the reference to ‘‘baffles’’ does notuse the word ‘‘means,’’ and we have heldthat the absence of that term creates arebuttable presumption that section 112,paragraph 6, does not apply. See Person-alized Media Communications, LLC v.Int’l Trade Comm’n, 161 F.3d 696, 703–04(Fed.Cir.1998).

Means-plus-function claiming appliesonly to purely functional limitations thatdo not provide the structure that performsthe recited function. See Watts v. XLSys., Inc., 232 F.3d 877, 880–81 (Fed.Cir.2000). While the baffles in the ’798 patentare clearly intended to perform severalfunctions, the term ‘‘baffles’’ is nonethelessstructural; it is not a purely functionalplaceholder in which structure is filled inby the specification. See TurboCare Div.of Demag Delaval Turbomachinery Corp.v. Gen. Elec. Co., 264 F.3d 1111, 1121(Fed.Cir.2001) (reasoning that nothing inthe specification or prosecution historysuggests that the patentee used the term‘‘compressed spring’’ to denote any struc-ture that is capable of performing the

specified function); Greenberg v. EthiconEndo–Surgery, Inc., 91 F.3d 1580, 1583(Fed.Cir.1996) (construing the term ‘‘de-tent mechanism’’ to refer to particularstructure, even though the term has func-tional connotations). The claims and thespecification unmistakably establish thatthe ‘‘steel baffles’’ refer to particular phys-ical apparatus. The claim characterizesthe baffles as ‘‘extend[ing] inwardly’’ fromthe steel shell walls, which plainly impliesthat the baffles are structures. The speci-fication likewise makes clear that the term‘‘steel baffles’’ refers to particular internalwall structures and is not simply a generaldescription of any structure that will per-form a particular function. See, e.g., ’798patent, col. 4, ll. 25–26 (‘‘the load bearingbaffles 16 are optionally used with longerpanels’’); id., col. 4, ll. 49–50 (opposingpanels are ‘‘compressed between theflange 35 and the baffle 26’’). Because theterm ‘‘baffles’’ is not subject to section 112,paragraph 6, we agree with the panel thatthe district court erred by limiting theterm to corresponding structures disclosedin the specification and their equivalents.Accordingly, we must determine the cor-rect construction of the structural term‘‘baffles,’’ as used in the ’798 patent.

II

The first paragraph of section 112 of thePatent Act, 35 U.S.C. § 112, states thatthe specification

shall contain a written description of theinvention, and of the manner and pro-cess of making and using it, in such full,clear, concise, and exact terms as toenable any person skilled in the art towhich it pertains TTT to make and usethe same TTTT

The second paragraph of section 112 pro-vides that the specification

shall conclude with one or more claimsparticularly pointing out and distinctly


claiming the subject matter which theapplicant regards as his invention.

Those two paragraphs of section 112frame the issue of claim interpretation forus. The second paragraph requires us tolook to the language of the claims to deter-mine what ‘‘the applicant regards as hisinvention.’’ On the other hand, the firstparagraph requires that the specificationdescribe the invention set forth in theclaims. The principal question that thiscase presents to us is the extent to whichwe should resort to and rely on a patent’sspecification in seeking to ascertain theproper scope of its claims.

This is hardly a new question. The roleof the specification in claim constructionhas been an issue in patent law decisionsin this country for nearly two centuries.We addressed the relationship between thespecification and the claims at some lengthin our en banc opinion in Markman v.Westview Instruments, Inc., 52 F.3d 967,979–81 (Fed.Cir.1995) (en banc), aff’d, 517U.S. 370, 116 S.Ct. 1384, 134 L.Ed.2d 577(1996). We again summarized the applica-ble principles in Vitronics Corp. v. Concep-tronic, Inc., 90 F.3d 1576 (Fed.Cir.1996),and more recently in Innova/Pure Water,Inc. v. Safari Water Filtration Systems,Inc., 381 F.3d 1111 (Fed.Cir.2004). Whatwe said in those cases bears restating, forthe basic principles of claim constructionoutlined there are still applicable, and wereaffirm them today. We have also previ-ously considered the use of dictionaries inclaim construction. What we have said inthat regard requires clarification.

A

[2] It is a ‘‘bedrock principle’’ of patentlaw that ‘‘the claims of a patent define theinvention to which the patentee is entitledthe right to exclude.’’ Innova, 381 F.3d at1115; see also Vitronics, 90 F.3d at 1582(‘‘we look to the words of the claims them-

selves TTT to define the scope of the pat-ented invention’’); Markman, 52 F.3d at980 (‘‘The written description part of thespecification itself does not delimit theright to exclude. That is the function andpurpose of claims.’’). That principle hasbeen recognized since at least 1836, whenCongress first required that the specifica-tion include a portion in which the inventor‘‘shall particularly specify and point outthe part, improvement, or combination,which he claims as his own invention ordiscovery.’’ Act of July 4, 1836, ch. 357,§ 6, 5 Stat. 117, 119. In the followingyears, the Supreme Court made clear thatthe claims are ‘‘of primary importance, inthe effort to ascertain precisely what it isthat is patented.’’ Merrill v. Yeomans, 94U.S. 568, 570, 24 L.Ed. 235 (1876). Be-cause the patentee is required to ‘‘defineprecisely what his invention is,’’ the Courtexplained, it is ‘‘unjust to the public, aswell as an evasion of the law, to construe itin a manner different from the plain im-port of its terms.’’ White v. Dunbar, 119U.S. 47, 52, 7 S.Ct. 72, 30 L.Ed. 303 (1886);see also Cont’l Paper Bag Co. v. E. PaperBag Co., 210 U.S. 405, 419, 28 S.Ct. 748, 52L.Ed. 1122 (1908) (‘‘the claims measure theinvention’’); McCarty v. Lehigh ValleyR.R. Co., 160 U.S. 110, 116, 16 S.Ct. 240,40 L.Ed. 358 (1895) (‘‘if we once begin toinclude elements not mentioned in theclaim, in order to limit such claim TTT, weshould never know where to stop’’); AroMfg. Co. v. Convertible Top ReplacementCo., 365 U.S. 336, 339, 81 S.Ct. 599, 5L.Ed.2d 592 (1961) (‘‘the claims made inthe patent are the sole measure of thegrant’’).

[3] We have frequently stated that thewords of a claim ‘‘are generally given theirordinary and customary meaning.’’ Vi-tronics, 90 F.3d at 1582; see also Toro Co.v. White Consol. Indus., Inc., 199 F.3d1295, 1299 (Fed.Cir.1999); Renishaw PLC


v. Marposs Societa’ per Azioni, 158 F.3d1243, 1249 (Fed.Cir.1998). We have madeclear, moreover, that the ordinary and cus-tomary meaning of a claim term is themeaning that the term would have to aperson of ordinary skill in the art in ques-tion at the time of the invention, i.e., as ofthe effective filing date of the patent appli-cation. See Innova, 381 F.3d at 1116 (‘‘Acourt construing a patent claim seeks toaccord a claim the meaning it would haveto a person of ordinary skill in the art atthe time of the invention.’’); Home Diag-nostics, Inc. v. LifeScan, Inc., 381 F.3d1352, 1358 (Fed.Cir.2004) (‘‘customarymeaning’’ refers to the ‘‘customary mean-ing in [the] art field’’); Ferguson Beaure-gard/Logic Controls v. Mega Sys., LLC,350 F.3d 1327, 1338 (Fed.Cir.2003) (claimterms ‘‘are examined through the viewingglass of a person skilled in the art’’); seealso PC Connector Solutions LLC v.SmartDisk Corp., 406 F.3d 1359, 1363(Fed.Cir.2005) (meaning of claim ‘‘must beinterpreted as of [the] effective filing date’’of the patent application); Schering Corp.v. Amgen Inc., 222 F.3d 1347, 1353 (Fed.Cir.2000) (same).

The inquiry into how a person of ordi-nary skill in the art understands a claimterm provides an objective baseline fromwhich to begin claim interpretation. SeeInnova, 381 F.3d at 1116. That startingpoint is based on the well-settled under-standing that inventors are typically per-sons skilled in the field of the inventionand that patents are addressed to andintended to be read by others of skill inthe pertinent art. See Verve, LLC v.Crane Cams, Inc., 311 F.3d 1116, 1119(Fed.Cir.2002) (patent documents aremeant to be ‘‘a concise statement for per-sons in the field’’); In re Nelson, 47C.C.P.A. 1031, 280 F.2d 172, 181 (1960)(‘‘The descriptions in patents are not ad-dressed to the public generally, to lawyersor to judges, but, as section 112 says, to

those skilled in the art to which the inven-tion pertains or with which it is most near-ly connected.’’).

[4] Importantly, the person of ordinaryskill in the art is deemed to read the claimterm not only in the context of the particu-lar claim in which the disputed term ap-pears, but in the context of the entirepatent, including the specification. Thiscourt explained that point well in Multi-form Desiccants, Inc. v. Medzam, Ltd., 133F.3d 1473, 1477 (Fed.Cir.1998):

It is the person of ordinary skill in thefield of the invention through whoseeyes the claims are construed. Suchperson is deemed to read the wordsused in the patent documents with anunderstanding of their meaning in thefield, and to have knowledge of any spe-cial meaning and usage in the field. Theinventor’s words that are used to de-scribe the invention—the inventor’s lexi-cography—must be understood and in-terpreted by the court as they would beunderstood and interpreted by a personin that field of technology. Thus thecourt starts the decisionmaking processby reviewing the same resources aswould that person, viz., the patent speci-fication and the prosecution history.

See also Medrad, Inc. v. MRI DevicesCorp., 401 F.3d 1313, 1319 (Fed.Cir.2005)(‘‘We cannot look at the ordinary meaningof the term TTT in a vacuum. Rather, wemust look at the ordinary meaning in thecontext of the written description and theprosecution history.’’); V–Formation, Inc.v. Benetton Group SpA, 401 F.3d 1307,1310 (Fed.Cir.2005) (intrinsic record ‘‘usu-ally provides the technological and tempo-ral context to enable the court to ascertainthe meaning of the claim to one of ordi-nary skill in the art at the time of theinvention’’); Unitherm Food Sys., Inc. v.Swift–Eckrich, Inc., 375 F.3d 1341, 1351


(Fed.Cir.2004) (proper definition is the‘‘definition that one of ordinary skill in theart could ascertain from the intrinsic evi-dence in the record’’).

B

In some cases, the ordinary meaning ofclaim language as understood by a personof skill in the art may be readily apparenteven to lay judges, and claim constructionin such cases involves little more than theapplication of the widely accepted meaningof commonly understood words. SeeBrown v. 3M, 265 F.3d 1349, 1352 (Fed.Cir.2001) (holding that the claims did ‘‘notrequire elaborate interpretation’’). Insuch circumstances, general purpose dic-tionaries may be helpful. In many casesthat give rise to litigation, however, deter-mining the ordinary and customary mean-ing of the claim requires examination ofterms that have a particular meaning in afield of art. Because the meaning of aclaim term as understood by persons ofskill in the art is often not immediatelyapparent, and because patentees frequent-ly use terms idiosyncratically, the courtlooks to ‘‘those sources available to thepublic that show what a person of skill inthe art would have understood disputedclaim language to mean.’’ Innova, 381F.3d at 1116. Those sources include ‘‘thewords of the claims themselves, the re-mainder of the specification, the prosecu-tion history, and extrinsic evidence con-cerning relevant scientific principles, themeaning of technical terms, and the stateof the art.’’ Id.; see also Gemstar–TVGuide Int’l, Inc. v. Int’l Trade Comm’n,383 F.3d 1352, 1364 (Fed.Cir.2004); Vi-tronics, 90 F.3d at 1582–83; Markman, 52F.3d at 979–80.

1

Quite apart from the written descriptionand the prosecution history, the claimsthemselves provide substantial guidance as

to the meaning of particular claim terms.See Vitronics, 90 F.3d at 1582; see alsoACTV, Inc. v. Walt Disney Co., 346 F.3d1082, 1088 (Fed.Cir.2003) (‘‘the context ofthe surrounding words of the claim alsomust be considered in determining the or-dinary and customary meaning of thoseterms’’).

To begin with, the context in which aterm is used in the asserted claim can behighly instructive. To take a simple exam-ple, the claim in this case refers to ‘‘steelbaffles,’’ which strongly implies that theterm ‘‘baffles’’ does not inherently meanobjects made of steel. This court’s casesprovide numerous similar examples inwhich the use of a term within the claimprovides a firm basis for construing theterm. See, e.g., Mars, Inc. v. H.J. HeinzCo., 377 F.3d 1369, 1374 (Fed.Cir.2004)(claim term ‘‘ingredients’’ construed inlight of the use of the term ‘‘mixture’’ inthe same claim phrase); Process ControlCorp. v. HydReclaim Corp., 190 F.3d 1350,1356 (Fed.Cir.1999) (claim term ‘‘dischargerate’’ construed in light of the use of thesame term in another limitation of thesame claim).

[5, 6] Other claims of the patent inquestion, both asserted and unasserted,can also be valuable sources of enlighten-ment as to the meaning of a claim term.Vitronics, 90 F.3d at 1582. Because claimterms are normally used consistentlythroughout the patent, the usage of a termin one claim can often illuminate the mean-ing of the same term in other claims. SeeRexnord Corp. v. Laitram Corp., 274 F.3d1336, 1342 (Fed.Cir.2001); CVI/Beta Ven-tures, Inc. v. Tura LP, 112 F.3d 1146, 1159(Fed.Cir.1997). Differences among claimscan also be a useful guide in understandingthe meaning of particular claim terms.See Laitram Corp. v. Rexnord, Inc., 939F.2d 1533, 1538 (Fed.Cir.1991). For ex-


ample, the presence of a dependent claimthat adds a particular limitation gives riseto a presumption that the limitation inquestion is not present in the independentclaim. See Liebel–Flarsheim Co. v. Me-drad, Inc., 358 F.3d 898, 910 (Fed.Cir.2004).

2

[7, 8] The claims, of course, do notstand alone. Rather, they are part of ‘‘afully integrated written instrument,’’Markman, 52 F.3d at 978, consisting prin-cipally of a specification that concludeswith the claims. For that reason, claims‘‘must be read in view of the specification,of which they are a part.’’ Id. at 979. Aswe stated in Vitronics, the specification ‘‘isalways highly relevant to the claim con-struction analysis. Usually, it is disposi-tive; it is the single best guide to themeaning of a disputed term.’’ 90 F.3d at1582.

This court and its predecessors havelong emphasized the importance of thespecification in claim construction. In Au-togiro Co. of America v. United States, 181Ct.Cl. 55, 384 F.2d 391, 397–98 (1967), theCourt of Claims characterized the specifi-cation as ‘‘a concordance for the claims,’’based on the statutory requirement thatthe specification ‘‘describe the manner andprocess of making and using’’ the patentedinvention. The Court of Customs and Pat-ent Appeals made a similar point. See Inre Fout, 675 F.2d 297, 300 (CCPA 1982)(‘‘Claims must always be read in light ofthe specification. Here, the specificationmakes plain what the appellants did anddid not invent TTTT’’).

Shortly after the creation of this court,Judge Rich wrote that ‘‘[t]he descriptivepart of the specification aids in ascertain-ing the scope and meaning of the claimsinasmuch as the words of the claims mustbe based on the description. The specifi-

cation is, thus, the primary basis for con-struing the claims.’’ Standard Oil Co. v.Am. Cyanamid Co., 774 F.2d 448, 452(Fed.Cir.1985). On numerous occasionssince then, we have reaffirmed that point,stating that ‘‘[t]he best source for under-standing a technical term is the specifica-tion from which it arose, informed, asneeded, by the prosecution history.’’ Mul-tiform Desiccants, 133 F.3d at 1478; Me-tabolite Labs., Inc. v. Lab. Corp. of Am.Holdings, 370 F.3d 1354, 1360 (Fed.Cir.2004) (‘‘In most cases, the best source fordiscerning the proper context of claimterms is the patent specification whereinthe patent applicant describes the inven-tion.’’); see also, e.g., Kinik Co. v. Int’lTrade Comm’n, 362 F.3d 1359, 1365 (Fed.Cir.2004) (‘‘The words of patent claimshave the meaning and scope with whichthey are used in the specification and theprosecution history.’’); Moba, B.V. v. Dia-mond Automation, Inc., 325 F.3d 1306,1315 (Fed.Cir.2003) (‘‘[T]he best indicatorof claim meaning is its usage in context asunderstood by one of skill in the art at thetime of invention.’’).

That principle has a long pedigree inSupreme Court decisions as well. SeeHogg v. Emerson, 47 U.S. (6 How.) 437,482, 12 L.Ed. 505 (1848) (the specificationis a ‘‘component part of the patent’’ and ‘‘isas much to be considered with the [letterspatent] in construing them, as any paperreferred to in a deed or other contract’’);Bates v. Coe, 98 U.S. 31, 38, 25 L.Ed. 68(1878) (‘‘in case of doubt or ambiguity it isproper in all cases to refer back to thedescriptive portions of the specification toaid in solving the doubt or in ascertainingthe true intent and meaning of the lan-guage employed in the claims’’); White v.Dunbar, 119 U.S. 47, 51, 7 S.Ct. 72, 30L.Ed. 303 (1886) (specification is appropri-ately resorted to ‘‘for the purpose of betterunderstanding the meaning of the claim’’);


Schriber–Schroth Co. v. Cleveland TrustCo., 311 U.S. 211, 217, 61 S.Ct. 235, 85L.Ed. 132 (1940) (‘‘The claims of a patentare always to be read or interpreted inlight of its specifications.’’); United Statesv. Adams, 383 U.S. 39, 49, 86 S.Ct. 708, 15L.Ed.2d 572 (1966) (‘‘[I]t is fundamentalthat claims are to be construed in the lightof the specifications and both are to beread with a view to ascertaining the inven-tion.’’).

The importance of the specification inclaim construction derives from its statuto-ry role. The close kinship between thewritten description and the claims is en-forced by the statutory requirement thatthe specification describe the claimed in-vention in ‘‘full, clear, concise, and exactterms.’’ 35 U.S.C. § 112, para. 1; seeNetword, LLC v. Centraal Corp., 242 F.3d1347, 1352 (Fed.Cir.2001) (‘‘The claims aredirected to the invention that is describedin the specification; they do not havemeaning removed from the context fromwhich they arose.’’); see also Markman v.Westview Instruments, Inc., 517 U.S. 370,389, 116 S.Ct. 1384, 134 L.Ed.2d 577 (1996)(‘‘[A claim] term can be defined only in away that comports with the instrument asa whole.’’). In light of the statutory di-rective that the inventor provide a ‘‘full’’and ‘‘exact’’ description of the claimed in-vention, the specification necessarily in-forms the proper construction of theclaims. See Merck & Co. v. Teva Pharms.USA, Inc., 347 F.3d 1367, 1371 (Fed.Cir.2003) (‘‘A fundamental rule of claim con-struction is that terms in a patent docu-ment are construed with the meaning withwhich they are presented in the patentdocument. Thus claims must be construedso as to be consistent with the specifica-tion, of which they are a part.’’) (citationsomitted). In Renishaw, this court summa-rized that point succinctly:

Ultimately, the interpretation to begiven a term can only be determined

and confirmed with a full understandingof what the inventors actually inventedand intended to envelop with the claim.The construction that stays true to theclaim language and most naturally alignswith the patent’s description of the in-vention will be, in the end, the correctconstruction.

158 F.3d at 1250 (citations omitted).

[9, 10] Consistent with that generalprinciple, our cases recognize that thespecification may reveal a special definitiongiven to a claim term by the patentee thatdiffers from the meaning it would other-wise possess. In such cases, the inventor’slexicography governs. See CCS Fitness,Inc. v. Brunswick Corp., 288 F.3d 1359,1366 (Fed.Cir.2002). In other cases, thespecification may reveal an intentional dis-claimer, or disavowal, of claim scope by theinventor. In that instance as well, theinventor has dictated the correct claimscope, and the inventor’s intention, as ex-pressed in the specification, is regarded asdispositive. See SciMed Life Sys., Inc. v.Advanced Cardiovascular Sys., Inc., 242F.3d 1337, 1343–44 (Fed.Cir.2001).

The pertinence of the specification toclaim construction is reinforced by themanner in which a patent is issued. ThePatent and Trademark Office (‘‘PTO’’) de-termines the scope of claims in patentapplications not solely on the basis of theclaim language, but upon giving claimstheir broadest reasonable construction ‘‘inlight of the specification as it would beinterpreted by one of ordinary skill in theart.’’ In re Am. Acad. of Sci. Tech. Ctr.,367 F.3d 1359, 1364 (Fed.Cir.2004). In-deed, the rules of the PTO require thatapplication claims must ‘‘conform to theinvention as set forth in the remainder ofthe specification and the terms and phras-es used in the claims must find clear sup-port or antecedent basis in the description


so that the meaning of the terms in theclaims may be ascertainable by referenceto the description.’’ 37 C.F.R.§ 1.75(d)(1). It is therefore entirely ap-propriate for a court, when conductingclaim construction, to rely heavily on thewritten description for guidance as to themeaning of the claims.

3

[11, 12] In addition to consulting thespecification, we have held that a court‘‘should also consider the patent’s prose-cution history, if it is in evidence.’’Markman, 52 F.3d at 980; see also Gra-ham v. John Deere Co., 383 U.S. 1, 33, 86S.Ct. 684, 15 L.Ed.2d 545 (1966) (‘‘[A]n in-vention is construed not only in the lightof the claims, but also with reference tothe file wrapper or prosecution history inthe Patent Office.’’). The prosecution his-tory, which we have designated as part ofthe ‘‘intrinsic evidence,’’ consists of thecomplete record of the proceedings beforethe PTO and includes the prior art citedduring the examination of the patent.Autogiro, 384 F.2d at 399. Like the spec-ification, the prosecution history providesevidence of how the PTO and the inventorunderstood the patent. See Lemelson v.Gen. Mills, Inc., 968 F.2d 1202, 1206(Fed.Cir.1992). Furthermore, like thespecification, the prosecution history wascreated by the patentee in attempting toexplain and obtain the patent. Yet be-cause the prosecution history representsan ongoing negotiation between the PTOand the applicant, rather than the finalproduct of that negotiation, it often lacksthe clarity of the specification and thus isless useful for claim construction pur-poses. See Inverness Med. Switz. GmbHv. Warner Lambert Co., 309 F.3d 1373,1380–82 (Fed.Cir.2002) (the ambiguity ofthe prosecution history made it less rele-vant to claim construction); Athletic Al-ternatives, Inc. v. Prince Mfg., Inc., 73

F.3d 1573, 1580 (Fed.Cir.1996) (the ambi-guity of the prosecution history made it‘‘unhelpful as an interpretive resource’’ forclaim construction). Nonetheless, the pros-ecution history can often inform themeaning of the claim language by demon-strating how the inventor understood theinvention and whether the inventor limit-ed the invention in the course of prosecu-tion, making the claim scope narrowerthan it would otherwise be. Vitronics, 90F.3d at 1582–83; see also Chimie v. PPGIndus., Inc., 402 F.3d 1371, 1384 (Fed.Cir.2005) (‘‘The purpose of consulting theprosecution history in construing a claimis to ‘exclude any interpretation that wasdisclaimed during prosecution.’ ’’), quotingZMI Corp. v. Cardiac Resuscitator Corp.,844 F.2d 1576, 1580 (Fed.Cir.1988);Southwall Techs., Inc. v. Cardinal IG Co.,54 F.3d 1570, 1576 (Fed.Cir.1995).

C

[13] Although we have emphasized theimportance of intrinsic evidence in claimconstruction, we have also authorized dis-trict courts to rely on extrinsic evidence,which ‘‘consists of all evidence external tothe patent and prosecution history, includ-ing expert and inventor testimony, dictio-naries, and learned treatises.’’ Markman,52 F.3d at 980, citing Seymour v. Osborne,78 U.S. (11 Wall.) 516, 546, 20 L.Ed. 33(1870); see also Vitronics, 90 F.3d at 1583.However, while extrinsic evidence ‘‘canshed useful light on the relevant art,’’ wehave explained that it is ‘‘less significantthan the intrinsic record in determining‘the legally operative meaning of claim lan-guage.’ ’’ C.R. Bard, Inc. v. U.S. SurgicalCorp., 388 F.3d 858, 862 (Fed.Cir.2004),quoting Vanderlande Indus. NederlandBV v. Int’l Trade Comm’n, 366 F.3d 1311,1318 (Fed.Cir.2004); see also AstrazenecaAB v. Mutual Pharm. Co., 384 F.3d 1333,1337 (Fed.Cir.2004).


[14] Within the class of extrinsic evi-dence, the court has observed that dictio-naries and treatises can be useful in claimconstruction. See Renishaw, 158 F.3d at1250; Rexnord, 274 F.3d at 1344. Wehave especially noted the help that techni-cal dictionaries may provide to a court ‘‘tobetter understand the underlying technolo-gy’’ and the way in which one of skill in theart might use the claim terms. Vitronics,90 F.3d at 1584 n. 6. Because dictionaries,and especially technical dictionaries, en-deavor to collect the accepted meanings ofterms used in various fields of science andtechnology, those resources have beenproperly recognized as among the manytools that can assist the court in determin-ing the meaning of particular terminologyto those of skill in the art of the invention.See Teleflex, Inc. v. Ficosa N. Am. Corp.,299 F.3d 1313, 1325 (Fed.Cir.2002). Suchevidence, we have held, may be consideredif the court deems it helpful in determining‘‘the true meaning of language used in thepatent claims.’’ Markman, 52 F.3d at 980.

[15–17] We have also held that extrin-sic evidence in the form of expert testimo-ny can be useful to a court for a variety ofpurposes, such as to provide backgroundon the technology at issue, to explain howan invention works, to ensure that thecourt’s understanding of the technical as-pects of the patent is consistent with thatof a person of skill in the art, or to estab-lish that a particular term in the patent orthe prior art has a particular meaning inthe pertinent field. See Pitney Bowes,Inc. v. Hewlett–Packard Co., 182 F.3d1298, 1308–09 (Fed.Cir.1999); KeyPharms. v. Hercon Labs. Corp., 161 F.3d709, 716 (Fed.Cir.1998). However, conclu-sory, unsupported assertions by experts asto the definition of a claim term are notuseful to a court. Similarly, a court shoulddiscount any expert testimony ‘‘that isclearly at odds with the claim construction

mandated by the claims themselves, thewritten description, and the prosecutionhistory, in other words, with the writtenrecord of the patent.’’ Key Pharms., 161F.3d at 716.

We have viewed extrinsic evidence ingeneral as less reliable than the patent andits prosecution history in determining howto read claim terms, for several reasons.First, extrinsic evidence by definition isnot part of the patent and does not havethe specification’s virtue of being createdat the time of patent prosecution for thepurpose of explaining the patent’s scopeand meaning. Second, while claims areconstrued as they would be understood bya hypothetical person of skill in the art,extrinsic publications may not be writtenby or for skilled artisans and thereforemay not reflect the understanding of askilled artisan in the field of the patent.Third, extrinsic evidence consisting of ex-pert reports and testimony is generated atthe time of and for the purpose of litiga-tion and thus can suffer from bias that isnot present in intrinsic evidence. The ef-fect of that bias can be exacerbated if theexpert is not one of skill in the relevant artor if the expert’s opinion is offered in aform that is not subject to cross-examina-tion. See Senmed, Inc. v. Richard–AllanMed. Indus., Inc., 888 F.2d 815, 819 n. 8(Fed.Cir.1989). Fourth, there is a virtual-ly unbounded universe of potential extrin-sic evidence of some marginal relevancethat could be brought to bear on any claimconstruction question. In the course oflitigation, each party will naturally choosethe pieces of extrinsic evidence most favor-able to its cause, leaving the court with theconsiderable task of filtering the usefulextrinsic evidence from the fluff. SeeDaubert v. Merrell Dow Pharms., Inc., 509U.S. 579, 595, 113 S.Ct. 2786, 125 L.Ed.2d469 (1993) (‘‘Expert evidence can be bothpowerful and quite misleading because ofthe difficulty in evaluating it.’’). Finally,


undue reliance on extrinsic evidence posesthe risk that it will be used to change themeaning of claims in derogation of the‘‘indisputable public records consisting ofthe claims, the specification and the prose-cution history,’’ thereby undermining thepublic notice function of patents. South-wall Techs., 54 F.3d at 1578.

[18, 19] In sum, extrinsic evidence maybe useful to the court, but it is unlikely toresult in a reliable interpretation of patentclaim scope unless considered in the con-text of the intrinsic evidence. Nonethe-less, because extrinsic evidence can helpeducate the court regarding the field of theinvention and can help the court determinewhat a person of ordinary skill in the artwould understand claim terms to mean, itis permissible for the district court in itssound discretion to admit and use suchevidence. In exercising that discretion,and in weighing all the evidence bearingon claim construction, the court shouldkeep in mind the flaws inherent in eachtype of evidence and assess that evidenceaccordingly.

III

Although the principles outlined abovehave been articulated on numerous occa-sions, some of this court’s cases have sug-gested a somewhat different approach toclaim construction, in which the court hasgiven greater emphasis to dictionary defi-nitions of claim terms and has assigned aless prominent role to the specification andthe prosecution history. The leading casein this line is Texas Digital Systems, Inc.v. Telegenix, Inc., 308 F.3d 1193 (Fed.Cir.2002).

A

In Texas Digital, the court noted that‘‘dictionaries, encyclopedias and treatisesare particularly useful resources to assist

the court in determining the ordinary andcustomary meanings of claim terms.’’ 308F.3d at 1202. Those texts, the court ex-plained, are ‘‘objective resources that serveas reliable sources of information on theestablished meanings that would have beenattributed to the terms of the claims bythose of skill in the art,’’ and they ‘‘deserveno less fealty in the context of claim con-struction’’ than in any other area of law.Id. at 1203. The court added that becausewords often have multiple dictionarymeanings, the intrinsic record must beconsulted to determine which of the differ-ent possible dictionary meanings is mostconsistent with the use of the term inquestion by the inventor. If more thanone dictionary definition is consistent withthe use of the words in the intrinsic rec-ord, the court stated, ‘‘the claim terms maybe construed to encompass all such consis-tent meanings.’’ Id.

The Texas Digital court further ex-plained that the patent’s specification andprosecution history must be consulted todetermine if the patentee has used ‘‘thewords [of the claim] in a manner clearlyinconsistent with the ordinary meaning re-flected, for example, in a dictionary defini-tion.’’ 308 F.3d at 1204. The court identi-fied two circumstances in which such aninconsistency may be found. First, thecourt stated, ‘‘the presumption in favor ofa dictionary definition will be overcomewhere the patentee, acting as his or herown lexicographer, has clearly set forth anexplicit definition of the term differentfrom its ordinary meaning.’’ Id. Second,‘‘the presumption also will be rebutted ifthe inventor has disavowed or disclaimedscope of coverage, by using words or ex-pressions of manifest exclusion or restric-tion, representing a clear disavowal ofclaim scope.’’ Id.

The Texas Digital court explained thatit advanced the methodology set forth in


that opinion in an effort to combat whatthis court has termed ‘‘one of the cardinalsins of patent law—reading a limitationfrom the written description into theclaims,’’ SciMed Life Sys., 242 F.3d at1340. The court concluded that it is im-proper to consult ‘‘the written descriptionand prosecution history as a threshold stepin the claim construction process, beforeany effort is made to discern the ordinaryand customary meanings attributed to thewords themselves.’’ Texas Digital, 308F.3d at 1204. To do so, the court rea-soned, ‘‘invites a violation of our precedentcounseling against importing limitationsinto the claims.’’ Id. Summarizing itsanalysis, the Texas Digital court stated:

By examining relevant dictionaries,encyclopedias, and treatises to ascertainpossible meanings that would have beenattributed to the words of the claims bythose skilled in the art, and by furtherutilizing the intrinsic record to selectfrom those possible meanings the one orones most consistent with the use of thewords by the inventor, the full breadthof the limitations intended by the inven-tor will be more accurately determinedand the improper importation of unin-tended limitations from the written de-scription into the claims will be moreeasily avoided.

Id. at 1205.

B

Although the concern expressed by thecourt in Texas Digital was valid, the meth-odology it adopted placed too much reli-ance on extrinsic sources such as dictionar-ies, treatises, and encyclopedias and toolittle on intrinsic sources, in particular thespecification and prosecution history.While the court noted that the specifica-tion must be consulted in every case, itsuggested a methodology for claim inter-pretation in which the specification should

be consulted only after a determination ismade, whether based on a dictionary, trea-tise, or other source, as to the ordinarymeaning or meanings of the claim term indispute. Even then, recourse to the speci-fication is limited to determining whetherthe specification excludes one of the mean-ings derived from the dictionary, whetherthe presumption in favor of the dictionarydefinition of the claim term has been over-come by ‘‘an explicit definition of the termdifferent from its ordinary meaning,’’ orwhether the inventor ‘‘has disavowed ordisclaimed scope of coverage, by usingwords or expressions of manifest exclusionor restriction, representing a clear disa-vowal of claim scope.’’ 308 F.3d at 1204.In effect, the Texas Digital approach lim-its the role of the specification in claimconstruction to serving as a check on thedictionary meaning of a claim term if thespecification requires the court to concludethat fewer than all the dictionary defini-tions apply, or if the specification containsa sufficiently specific alternative definitionor disavowal. See, e.g., Texas Digital, 308F.3d at 1202 (‘‘unless compelled otherwise,a court will give a claim term the fullrange of its ordinary meaning’’); Nystromv. TREX Co., 374 F.3d 1105, 1111–13 (Fed.Cir.2004) (ascertaining the ‘‘full range’’ ofthe ordinary meaning of the term ‘‘board’’through a collection of dictionary defini-tions, and stating that those candidate def-initions should be removed from consider-ation only if they were ‘‘disclaimed’’ in thewritten description or prosecution history);Inverness Med. Switz., 309 F.3d at 1379(claim should be construed to encompassmultiple dictionary meanings unless ‘‘thespecification or prosecution history clearlydemonstrates that only one of the multiplemeanings was intended’’). That approach,in our view, improperly restricts the roleof the specification in claim construction.

Assigning such a limited role to thespecification, and in particular requiring


that any definition of claim language in thespecification be express, is inconsistentwith our rulings that the specification is‘‘the single best guide to the meaning of adisputed term,’’ and that the specification‘‘acts as a dictionary when it expresslydefines terms used in the claims or when itdefines terms by implication.’’ Vitronics,90 F.3d at 1582; Irdeto Access, Inc. v.Echostar Satellite Corp., 383 F.3d 1295,1300 (Fed.Cir.2004) (‘‘Even when guidanceis not provided in explicit definitional for-mat, the specification may define claimterms by implication such that the mean-ing may be found in or ascertained by areading of the patent documents.’’) (cita-tions omitted); Novartis Pharms. Corp. v.Abbott Labs., 375 F.3d 1328, 1334–35 (Fed.Cir.2004) (same); Bell Atl. Network Servs.,Inc. v. Covad Communications Group,Inc., 262 F.3d 1258, 1268 (Fed.Cir.2001)(‘‘[A] claim term may be clearly redefinedwithout an explicit statement of redefini-tion.’’).

The main problem with elevating thedictionary to such prominence is that itfocuses the inquiry on the abstract mean-ing of words rather than on the meaning ofclaim terms within the context of the pat-ent. Properly viewed, the ‘‘ordinarymeaning’’ of a claim term is its meaning tothe ordinary artisan after reading the en-tire patent. Yet heavy reliance on thedictionary divorced from the intrinsic evi-dence risks transforming the meaning ofthe claim term to the artisan into themeaning of the term in the abstract, out ofits particular context, which is the specifi-cation. The patent system is based on theproposition that claims cover only the in-vented subject matter. As the SupremeCourt has stated, ‘‘[i]t seems to us thatnothing can be more just and fair, both tothe patentee and the public, than that theformer should understand, and correctlydescribe, just what he has invented, andfor what he claims a patent.’’ Merrill v.

Yeomans, 94 U.S. at 573–74. The use of adictionary definition can conflict with thatdirective because the patent applicant didnot create the dictionary to describe theinvention. Thus, there may be a discon-nect between the patentee’s responsibilityto describe and claim his invention, andthe dictionary editors’ objective of aggre-gating all possible definitions for particularwords.

Although the Texas Digital line of casespermit the dictionary definition to be nar-rowed in some circumstances even whenthere is not an explicit disclaimer or redef-inition in the specification, too often thatline of cases has been improperly reliedupon to condone the adoption of a dictio-nary definition entirely divorced from thecontext of the written description. Theproblem is that if the district court startswith the broad dictionary definition in ev-ery case and fails to fully appreciate howthe specification implicitly limits that defi-nition, the error will systematically causethe construction of the claim to be undulyexpansive. The risk of systematic over-breadth is greatly reduced if the courtinstead focuses at the outset on how thepatentee used the claim term in the claims,specification, and prosecution history, rath-er than starting with a broad definitionand whittling it down.

Dictionaries, by their nature, provide anexpansive array of definitions. Generaldictionaries, in particular, strive to collectall uses of particular words, from the com-mon to the obscure. By design, generaldictionaries collect the definitions of aterm as used not only in a particular artfield, but in many different settings. Insuch circumstances, it is inevitable that themultiple dictionary definitions for a termwill extend beyond the ‘‘construction of thepatent [that] is confirmed by the avowedunderstanding of the patentee, expressedby him, or on his behalf, when his applica-


tion for the original patent was pending.’’Goodyear Dental Vulcanite Co. v. Davis,102 U.S. 222, 227, 26 L.Ed. 149 (1880).Thus, the use of the dictionary may extendpatent protection beyond what shouldproperly be afforded by the inventor’s pat-ent. See Smith v. Snow, 294 U.S. 1, 14, 55S.Ct. 279, 79 L.Ed. 721 (1935) (‘‘if theclaim were fairly susceptible of two con-structions, that should be adopted whichwill secure to the patentee his actual in-vention ’’) (emphasis added). For thatreason, we have stated that ‘‘a general-usage dictionary cannot overcome art-spe-cific evidence of the meaning’’ of a claimterm. Vanderlande Indus. Nederland,366 F.3d at 1321; see also Renishaw, 158F.3d at 1250, quoting Liebscher v. Booth-royd, 46 C.C.P.A. 701, 258 F.2d 948, 951(CCPA 1958) (‘‘Indiscriminate reliance ondefinitions found in dictionaries can oftenproduce absurd resultsTTTT One need notarbitrarily pick and choose from the vari-ous accepted definitions of a word to de-cide which meaning was intended as theword is used in a given claim. The subjectmatter, the context, etc., will more oftenthan not lead to the correct conclusion.’’).

Even technical dictionaries or treatises,under certain circumstances, may sufferfrom some of these deficiencies. There isno guarantee that a term is used in thesame way in a treatise as it would be bythe patentee. In fact, discrepancies be-tween the patent and treatises are apt tobe common because the patent by its na-ture describes something novel. See Auto-giro, 384 F.2d at 397 (‘‘Often the inventionis novel and words do not exist to describeit. The dictionary does not always keepabreast of the inventor. It cannot.’’).

Moreover, different dictionaries maycontain somewhat different sets of defini-tions for the same words. A claim shouldnot rise or fall based upon the preferencesof a particular dictionary editor, or the

court’s independent decision, uninformedby the specification, to rely on one dictio-nary rather than another. Finally, theauthors of dictionaries or treatises maysimplify ideas to communicate them mosteffectively to the public and may thuschoose a meaning that is not pertinent tothe understanding of particular claim lan-guage. See generally Ellen P. Aprill, TheLaw of the Word: Dictionary Shopping inthe Supreme Court, 30 Ariz. St. L.J. 275,293–314 (1998). The resulting definitionstherefore do not necessarily reflect theinventor’s goal of distinctly setting forthhis invention as a person of ordinary skillin that particular art would understand it.

[20] As we have noted above, however,we do not intend to preclude the appropri-ate use of dictionaries. Dictionaries orcomparable sources are often useful to as-sist in understanding the commonly under-stood meaning of words and have beenused both by our court and the SupremeCourt in claim interpretation. See ExhibitSupply Co. v. Ace Patents Corp., 315 U.S.126, 134, 62 S.Ct. 513, 86 L.Ed. 736 (1942)(relying on dictionaries to construe theclaim term ‘‘embedded’’); Weber Elec. Co.v. E.H. Freeman Elec. Co., 256 U.S. 668,678, 41 S.Ct. 600, 65 L.Ed. 1162 (1921)(approving circuit court’s use of dictionarydefinitions to define claim terms); Reni-shaw, 158 F.3d at 1247–53 (approving theuse of dictionaries with proper respect forthe role of intrinsic evidence). A dictionarydefinition has the value of being an unbi-ased source ‘‘accessible to the public inadvance of litigation.’’ Vitronics, 90 F.3dat 1585. As we said in Vitronics, judgesare free to consult dictionaries and techni-cal treatises

at any time in order to better under-stand the underlying technology andmay also rely on dictionary definitionswhen construing claim terms, so long asthe dictionary definition does not contra-


dict any definition found in or ascer-tained by a reading of the patent docu-ments.

Id. at 1584 n. 6.We also acknowledge that the purpose

underlying the Texas Digital line ofcases—to avoid the danger of reading limi-tations from the specification into theclaim—is sound. Moreover, we recognizethat the distinction between using thespecification to interpret the meaning of aclaim and importing limitations from thespecification into the claim can be a diffi-cult one to apply in practice. See ComarkCommunications, Inc. v. Harris Corp., 156F.3d 1182, 1186–87 (Fed.Cir.1998) (‘‘thereis sometimes a fine line between reading aclaim in light of the specification, and read-ing a limitation into the claim from thespecification’’). However, the line betweenconstruing terms and importing limitationscan be discerned with reasonable certaintyand predictability if the court’s focus re-mains on understanding how a person ofordinary skill in the art would understandthe claim terms. For instance, althoughthe specification often describes very spe-cific embodiments of the invention, wehave repeatedly warned against confiningthe claims to those embodiments. See,e.g., Nazomi Communications, Inc. v.ARM Holdings, PLC, 403 F.3d 1364, 1369(Fed.Cir.2005) (claims may embrace ‘‘dif-ferent subject matter than is illustrated inthe specific embodiments in the specifica-tion’’); Liebel–Flarsheim, 358 F.3d at 906–08; Teleflex, 299 F.3d at 1327; SRI Int’l v.Matsushita Elec. Corp. of Am., 775 F.2d1107, 1121 (Fed.Cir.1985). In particular,we have expressly rejected the contentionthat if a patent describes only a singleembodiment, the claims of the patent mustbe construed as being limited to that em-bodiment. Gemstar–TV Guide, 383 F.3dat 1366. That is not just because section112 of the Patent Act requires that theclaims themselves set forth the limits of

the patent grant, but also because personsof ordinary skill in the art rarely wouldconfine their definitions of terms to theexact representations depicted in the em-bodiments.

To avoid importing limitations from thespecification into the claims, it is importantto keep in mind that the purposes of thespecification are to teach and enable thoseof skill in the art to make and use theinvention and to provide a best mode fordoing so. See Spectra–Physics, Inc. v.Coherent, Inc., 827 F.2d 1524, 1533 (Fed.Cir.1987). One of the best ways to teach aperson of ordinary skill in the art how tomake and use the invention is to providean example of how to practice the inven-tion in a particular case. Much of thetime, upon reading the specification in thatcontext, it will become clear whether thepatentee is setting out specific examples ofthe invention to accomplish those goals, orwhether the patentee instead intends forthe claims and the embodiments in thespecification to be strictly coextensive.See SciMed Life Sys., 242 F.3d at 1341.The manner in which the patentee uses aterm within the specification and claimsusually will make the distinction apparent.See Snow v. Lake Shore & M.S. Ry. Co.,121 U.S. 617, 630, 7 S.Ct. 1343, 30 L.Ed.1004 (1887) (it was clear from the specifica-tion that there was ‘‘nothing in the contextto indicate that the patentee contemplatedany alternative’’ embodiment to the onepresented).

In the end, there will still remain somecases in which it will be hard to determinewhether a person of skill in the art wouldunderstand the embodiments to define theouter limits of the claim term or merely tobe exemplary in nature. While that taskmay present difficulties in some cases, wenonetheless believe that attempting to re-solve that problem in the context of the


particular patent is likely to capture thescope of the actual invention more accu-rately than either strictly limiting thescope of the claims to the embodimentsdisclosed in the specification or divorcingthe claim language from the specification.

[21] In Vitronics, this court grappledwith the same problem and set forthguidelines for reaching the correct claimconstruction and not imposing improperlimitations on claims. 90 F.3d at 1582.The underlying goal of our decision inVitronics was to increase the likelihoodthat a court will comprehend how a personof ordinary skill in the art would under-stand the claim terms. See id. at 1584. Inthat process, we recognized that there isno magic formula or catechism for con-ducting claim construction. Nor is thecourt barred from considering any particu-lar sources or required to analyze sourcesin any specific sequence, as long as thosesources are not used to contradict claimmeaning that is unambiguous in light ofthe intrinsic evidence. See id. at 1583–84;Intel Corp. v. VIA Techs., Inc., 319 F.3d1357, 1367 (Fed.Cir.2003). For example, ajudge who encounters a claim term whilereading a patent might consult a generalpurpose or specialized dictionary to beginto understand the meaning of the term,before reviewing the remainder of the pat-ent to determine how the patentee hasused the term. The sequence of stepsused by the judge in consulting varioussources is not important; what matters isfor the court to attach the appropriateweight to be assigned to those sources inlight of the statutes and policies that in-form patent law. Vitronics, 90 F.3d at1582. In Vitronics, we did not attempt toprovide a rigid algorithm for claim con-struction, but simply attempted to explainwhy, in general, certain types of evidenceare more valuable than others. Today, weadhere to that approach and reaffirm the

approach to claim construction outlined inthat case, in Markman, and in Innova.We now turn to the application of thoseprinciples to the case at bar.

IV

A

[22] The critical language of claim 1 ofthe ’798 patent—‘‘further means disposedinside the shell for increasing its load bear-ing capacity comprising internal steel baf-fles extending inwardly from the steelshell walls’’—imposes three clear require-ments with respect to the baffles. First,the baffles must be made of steel. Second,they must be part of the load-bearingmeans for the wall section. Third, theymust be pointed inward from the walls.Both parties, stipulating to a dictionarydefinition, also conceded that the term‘‘baffles’’ refers to objects that check, im-pede, or obstruct the flow of something.The intrinsic evidence confirms that a per-son of skill in the art would understandthat the term ‘‘baffles,’’ as used in the ’798patent, would have that generic meaning.

The other claims of the ’798 patent spec-ify particular functions to be served by thebaffles. For example, dependent claim 2states that the baffles may be ‘‘orientedwith the panel sections disposed at anglesfor deflecting projectiles such as bulletsable to penetrate the steel plates.’’ Theinclusion of such a specific limitation onthe term ‘‘baffles’’ in claim 2 makes itlikely that the patentee did not contem-plate that the term ‘‘baffles’’ already con-tained that limitation. See Dow Chem. Co.v. United States, 226 F.3d 1334, 1341–42(Fed.Cir.2000) (concluding that an inde-pendent claim should be given broaderscope than a dependent claim to avoidrendering the dependent claim redundant).Independent claim 17 further supportsthat proposition. It states that baffles are


placed ‘‘projecting inwardly from the outershell at angles tending to deflect projec-tiles that penetrate the outer shell.’’ Thatlimitation would be unnecessary if personsof skill in the art understood that thebaffles inherently served such a function.See TurboCare, 264 F.3d at 1123 (claimterms should not be read to contain alimitation ‘‘where another claim restrictsthe invention in exactly the [same] man-ner’’). Dependent claim 6 provides an ad-ditional requirement for the baffles, stat-ing that ‘‘the internal baffles of both outerpanel sections overlap and interlock at an-gles providing deflector panels extendingfrom one end of the module to the other.’’If the baffles recited in claim 1 were inher-ently placed at specific angles, or inter-locked to form an intermediate barrier,claim 6 would be redundant.

The specification further supports theconclusion that persons of ordinary skill inthe art would understand the baffles recit-ed in the ’798 patent to be load-bearingobjects that serve to check, impede, orobstruct flow. At several points, the speci-fication discusses positioning the baffles soas to deflect projectiles. See ’798 patent,col. 2, II. 13–15; id., col. 5, II. 17–19. Thepatent states that one advantage of theinvention over the prior art is that ‘‘[t]herehave not been effective ways of dealingwith these powerful impact weapons with

inexpensive housing.’’ Id., col. 3, II. 28–30.While that statement makes clear the in-vention envisions baffles that serve thatfunction, it does not imply that in order toqualify as baffles within the meaning of theclaims, the internal support structuresmust serve the projectile-deflecting func-tion in all the embodiments of all theclaims. The specification must teach andenable all the claims, and the section of thewritten description discussing the use ofbaffles to deflect projectiles serves thatpurpose for claims 2, 6, 17, and 23, whichspecifically claim baffles that deflect pro-jectiles. See In re Wright, 999 F.2d 1557,1561 (Fed.Cir.1993).

The specification discusses several otherpurposes served by the baffles. For ex-ample, the baffles are described as provid-ing structural support. The patent statesthat one way to increase load-bearing ca-pacity is to use ‘‘at least in part inwardlydirected steel baffles 15, 16.’’ ’798 patent,col. 4, II. 14–15. The baffle 16 is de-scribed as a ‘‘strengthening triangular baf-fle.’’ Id., col. 4, line 37. Importantly,Figures 4 and 6 do not show the baffles aspart of an ‘‘intermediate interlocking, butnot solid, internal barrier.’’ In those fig-ures, the baffle 16 simply provides struc-tural support for one of the walls, as de-picted below:


Other uses for the baffles are listed inthe specification as well. In Figure 7, theoverlapping flanges ‘‘provide for over-

lapping and interlocking the baffles to pro-duce substantially an intermediate barrierwall between the opposite [wall] faces’’:

’798 patent, col. 5, II. 26–29. Those bafflesthus create small compartments that canbe filled with either sound and thermalinsulation or rock and gravel to stop pro-jectiles. Id., col. 5, II. 29–34. By separat-ing the interwall area into compartments(see, e.g., compartment 55 in Figure 7), theuser of the modules can choose differenttypes of material for each compartment, so

that the module can be ‘‘easily customtailored for the specific needs of each in-stallation.’’ Id., col. 5, II. 36–37. Whenmaterial is placed into the wall duringinstallation, the baffles obstruct the flow ofmaterial from one compartment to anotherso that this ‘‘custom tailoring’’ is possible.

[23] The fact that the written descrip-tion of the ’798 patent sets forth multiple


objectives to be served by the baffles recit-ed in the claims confirms that the term‘‘baffles’’ should not be read restrictively torequire that the baffles in each case serveall of the recited functions. We have heldthat ‘‘[t]he fact that a patent asserts thatan invention achieves several objectivesdoes not require that each of the claims beconstrued as limited to structures that arecapable of achieving all of the objectives.’’Liebel–Flarsheim, 358 F.3d at 908; seealso Resonate Inc. v. Alteon Websystems,Inc., 338 F.3d 1360, 1367 (Fed.Cir.2003).Although deflecting projectiles is one ofthe advantages of the baffles of the ’798patent, the patent does not require thatthe inward extending structures always becapable of performing that function. Ac-cordingly, we conclude that a person ofskill in the art would not interpret thedisclosure and claims of the ’798 patent tomean that a structure extending inwardfrom one of the wall faces is a ‘‘baffle’’ if itis at an acute or obtuse angle, but is not a‘‘baffle’’ if it is disposed at a right angle.

B

[24] Invoking the principle that‘‘claims should be so construed, if possible,as to sustain their validity,’’ Rhine v. Ca-sio, Inc., 183 F.3d 1342, 1345 (Fed.Cir.1999), AWH argues that the term ‘‘baffles’’should be given a restrictive meaning be-cause if the term is not construed restric-tively, the asserted claims would be inval-id.

While we have acknowledged the maximthat claims should be construed to pre-serve their validity, we have not appliedthat principle broadly, and we have cer-tainly not endorsed a regime in which va-lidity analysis is a regular component ofclaim construction. See Nazomi Communi-cations, 403 F.3d at 1368–69. Instead, wehave limited the maxim to cases in which‘‘the court concludes, after applying all the

available tools of claim construction, thatthe claim is still ambiguous.’’ Liebel–Flar-sheim, 358 F.3d at 911; see also Genera-tion II Orthotics Inc. v. Med. Tech. Inc.,263 F.3d 1356, 1365 (Fed.Cir.2001)(‘‘[C]laims can only be construed to pre-serve their validity where the proposedclaim construction is ‘practicable,’ is basedon sound claim construction principles, anddoes not revise or ignore the explicit lan-guage of the claims.’’); Elekta InstrumentS.A. v. O.U.R. Scientific Int’l, Inc., 214F.3d 1302, 1309 (Fed.Cir.2000) (‘‘havingconcluded that the amended claim is sus-ceptible of only one reasonable construc-tion, we cannot construe the claim differ-ently from its plain meaning in order topreserve its validity’’); E.I. du Pont deNemours & Co. v. Phillips Petroleum Co.,849 F.2d 1430, 1434 (Fed.Cir.1988) (reject-ing argument that limitations should beadded to claims to preserve the validity ofthe claims). In such cases, we have lookedto whether it is reasonable to infer that thePTO would not have issued an invalid pat-ent, and that the ambiguity in the claimlanguage should therefore be resolved in amanner that would preserve the patent’svalidity.

That is the rationale that gave rise tothe maxim in the first place. In Klein v.Russell, 86 U.S. (19 Wall.) 433, 466, 22L.Ed. 116 (1873), the owner of a reissuedpatent argued for a narrow construction ofthe patent, while the accused infringer ar-gued for a broader construction. TheCourt noted that the law ‘‘required thatthe reissue should be for the same inven-tion as the original patent.’’ Id. Becausethe reissue, which was granted under thepredecessor to 35 U.S.C. § 251, wouldhave been improper under the broaderconstruction, the Court ‘‘presumed theCommissioner did his duty’’ and did notissue an invalid patent. For that reason,among others, the Court construed the


disputed claim language in a manner that‘‘sustain[ed] the patent and the construc-tion claimed by the patentee,’’ since that‘‘can be done consistently with the lan-guage which he has employed.’’ Id. Theapplicability of the doctrine in a particularcase therefore depends on the strength ofthe inference that the PTO would haverecognized that one claim interpretationwould render the claim invalid, and thatthe PTO would not have issued the patentassuming that to be the proper construc-tion of the term.

In this case, unlike in Klein and othercases in which the doctrine of construingclaims to preserve their validity has beeninvoked, the claim term at issue is notambiguous. Thus, it can be construedwithout the need to consider whether onepossible construction would render theclaim invalid while the other would not.The doctrine of construing claims to pre-serve their validity, a doctrine of limitedutility in any event, therefore has no appli-cability here.

In sum, we reject AWH’s arguments infavor of a restrictive definition of the term‘‘baffles.’’ Because we disagree with thedistrict court’s claim construction, we re-verse the summary judgment of nonin-fringement. In light of our decision onclaim construction, it is necessary to re-mand the infringement claims to the dis-trict court for further proceedings.

V

With respect to Mr. Phillips’s allegationof misappropriation of trade secrets, weagree with the panel’s decision upholdingthe district court’s ruling on that issue, inwhich the district court dismissed thetrade secret claim on statute of limitationsgrounds. See Phillips, 363 F.3d at 1214–1216. Accordingly, based on the panel’sdisposition of that issue, we affirm thedistrict court’s dismissal of the trade se-

cret claim. With respect to AWH’s cross-appeal, we also agree with the panel’s rea-soning and its conclusion that the cross-appeal is improper. See id. at 1216. Wetherefore dismiss the cross-appeal.

VI

In our order granting rehearing enbanc, we asked the parties to brief variousquestions, including the following: ‘‘Con-sistent with the Supreme Court’s decisionin Markman v. Westview Instruments, 517U.S. 370, 116 S.Ct. 1384, 134 L.Ed.2d 577(1996), and our en banc decision in CyborCorp. v. FAS Technologies, Inc., 138 F.3d1448 (Fed.Cir.1998), is it appropriate forthis court to accord any deference to anyaspect of trial court claim construction rul-ings? If so, on what aspects, in whatcircumstances, and to what extent?’’ Afterconsideration of the matter, we have decid-ed not to address that issue at this time.We therefore leave undisturbed our prioren banc decision in Cybor.

Each party shall bear its own costs forthis appeal.

AFFIRMED IN PART, REVERSEDIN PART, DISMISSED IN PART, andREMANDED.

LOURIE, Circuit Judge, concurring inpart and dissenting in part, with whomPAULINE NEWMAN, Circuit Judge,joins.

I fully join the portion of the court’sopinion resolving the relative weights ofspecification and dictionaries in interpret-ing patent claims, in favor of the specifica-tion. I could elaborate more expansivelyon that topic, but Judge Bryson’s opinionfor the majority says it so well, there islittle reason for me to repeat its truths. Ialso agree with the court that claims neednot necessarily be limited to specific orpreferred embodiments in the specifica-tion, although they are limited to what is


contained in the overall disclosure of thespecification.

However, I do dissent from the court’sdecision to reverse and remand the districtcourt’s decision. The original panel deci-sion of this court, which implicitly decidedthe case based on the priorities that the enbanc court has now reaffirmed, interpretedthe claims in light of the specification andfound that the defendant did not infringethe claims. We affirmed the district court,which had arrived at a similar conclusion.The dissent from the panel decision reliedon the ‘‘dictionaries first’’ procedure, whichthe court now has decided not to follow.Thus, while the claim construction issuehad to be decided by the en banc court, Isee no reason for the court, having reaf-firmed the principle on which the districtjudge and the panel originally decided thecase, to send it back for further review.

The court premises its reverse-and-re-mand decision on the concept of claimdifferentiation and the reasoning that thecontested term ‘‘baffle’’ need not fulfill allof the functions set out for it in the specifi-cation. Reasonable people can differ onthose points. However, the court did nottake this case en banc because the fullcourt differed with the panel majority onthose disputable criteria. It did so to re-solve the claim construction issue, which ithas now done so well. Having done so, Ibelieve that it should simply affirm thedistrict court’s decision on the merits, con-sistently with that court’s rationale andthat of the panel that affirmed the districtcourt, which it now adopts.

I will not critique in detail particularstatements the majority makes in rational-izing its reversal of the district court’sdecision, such as ‘‘that a person of skill inthe art would not interpret the disclosureand claims of the ’798 patent to mean thata structure extending inward from one ofthe wall faces is a ‘baffle’ if it is at an acute

or obtuse angle, but is not a ‘baffle’ if it isdisposed at a right angle,’’ or that ‘‘thepatent does not require that the inwardextending structures always be capable ofperforming that function [deflecting pro-jectiles]’’ in order to be considered ‘baf-fles’.

I will simply point out that the specifica-tion contains no disclosure of baffles atright angles. Moreover, as the majoritycorrectly states, a patent specification isintended to describe one’s invention, and itis essential to read a specification in orderto interpret the meaning of the claims.This specification makes clear that the‘‘baffles’’ in this invention are angled.There is no reference to baffles that showthem to be other than angled. The ab-stract refers to ‘‘bullet deflecting TTT baf-fles.’’ Only angled baffles can deflect. Itthen mentions ‘‘internal baffles at anglesfor deflecting bullets.’’ That could not beclearer. The specification then refers sev-eral times to baffles, often to figures in thedrawings, all of which are to angled baf-fles. A compelling point is that the onlynumbered references to baffles (15, 16, 26,27, 30, and 31) all show angled baffles.

The specification further states thatsteel panels ‘‘form the internal baffles atangles for deflecting bullets.’’ It statesthat the baffles are ‘‘disposed at such an-gles that bullets which might penetrate theouter steel panels are deflected.’’ It ex-plains that if bullets ‘‘were to penetrate theouter steel wall, the baffles are disposed atangles which tend to deflect the bullets.’’There is no specific reference in this pat-ent to a baffle that is not angled at otherthan 90 .

While, as the majority states, the specifi-cation indicates that multiple objectivesare achieved by the invention, none of theother objectives is dependent upon wheth-er the baffles are at other than a 90 angle,whereas the constantly stated objective of


deflection of bullets is dependent uponsuch an angle.

Finally, even though claim constructionis a question of law, reviewable by thiscourt without formal deference, I do be-lieve that we ought to lean toward affir-mance of a claim construction in the ab-sence of a strong conviction of error. I donot have such a conviction in this case,after considering the district court’s opin-ion and the patent specification.

For these reasons, while I wholeheart-edly join the majority opinion in its discus-sion and resolution of the ‘‘specification v.dictionaries’’ issue, I would affirm the deci-sion below.

MAYER, Circuit Judge, with whomPAULINE NEWMAN, Circuit Judge,joins, dissenting.

Now more than ever I am convinced ofthe futility, indeed the absurdity, of thiscourt’s persistence in adhering to the false-hood that claim construction is a matter oflaw devoid of any factual component. Be-cause any attempt to fashion a coherentstandard under this regime is pointless, asillustrated by our many failed attempts todo so, I dissent.

This court was created for the purposeof bringing consistency to the patent field.See H.R.Rep. No. 312, 97th Cong., 1stSess. 20–23 (1981). Instead, we have tak-en this noble mandate, to reinvigorate thepatent and introduce predictability to thefield, and focused inappropriate power inthis court. In our quest to elevate ourimportance, we have, however, disregarded

our role as an appellate court; the result-ing mayhem has seriously undermined thelegitimacy of the process, if not the integri-ty of the institution.

In the name of uniformity, Cybor Corp.v. FAS Technologies, Inc., 138 F.3d 1448(Fed.Cir.1998) (en banc), held that claimconstruction does not involve subsidiary orunderlying questions of fact and that weare, therefore, unbridled by either the ex-pertise or efforts of the district court.1

What we have wrought, instead, is thesubstitution of a black box, as it so pejora-tively has been said of the jury, with theblack hole of this court. Out of this voidwe emit ‘‘legal’’ pronouncements by way of‘‘interpretive necromancy’’ 2; these rulingsresemble reality, if at all, only by chance.Regardless, and with a blind eye to theconsequences, we continue to struggle un-der this irrational and reckless regime,trying every alternative—dictionaries first,dictionaries second, never dictionaries, etc.,etc., etc.

Again today we vainly attempt to estab-lish standards by which this court willinterpret claims. But after proposing nofewer than seven questions, receiving morethan thirty amici curiae briefs, and whip-ping the bar into a frenzy of expectation,we say nothing new, but merely restatewhat has become the practice over the lastten years—that we will decide cases ac-cording to whatever mode or method re-sults in the outcome we desire, or at leastallows us a seemingly plausible way out ofthe case. I am not surprised by this.

1. The Supreme Court did not suggest in af-firming Markman v. Westview Instruments,Inc., 52 F.3d 967 (1995) (en banc), that claimconstruction is a purely legal question. 517U.S. 370, 116 S.Ct. 1384, 134 L.Ed.2d 577(1996). It held only that, as a policy matter,the judge, as opposed to the jury, shoulddetermine the meaning of a patent claim. SeeCybor, 138 F.3d at 1464 (Mayer, C.J., dissent-

ing) (explaining that ‘‘the [Supreme] Courtchose not to accept our formulation of claimconstruction: as a pure question of law to bedecided de novo in all cases on appeal’’).

2. See The Holmes Group, Inc. v. Vornado AirCirculation Sys., Inc., 535 U.S. 826, 833, 122S.Ct. 1889, 153 L.Ed.2d 13 (2002).


Indeed, there can be no workable stan-dards by which this court will interpretclaims so long as we are blind to thefactual component of the task. See Cooter& Gell v. Hartmarx Corp., 496 U.S. 384,405, 110 S.Ct. 2447, 110 L.Ed.2d 359 (1990)(‘‘Fact-bound resolutions cannot be madeuniform through appellate review, de novoor otherwise.’’ (quoting Mars Steel Corp. v.Cont’l Bank N.A., 880 F.2d 928, 936 (7thCir.1989))).3

Federal Rule of Civil Procedure 52(a)states that ‘‘[f]indings of fact TTT shall notbe set aside unless clearly erroneous, anddue regard shall be given to the opportuni-ty of the trial court to judge of the credi-bility of witnesses.’’ According to the Su-preme Court, this ‘‘[r]ule means what it

says’’—that findings of fact, even ‘‘thosedescribed as ‘ultimate facts’ because theymay determine the outcome of litigation,’’are to be reviewed deferentially on ap-peal.4 Bose Corp. v. Consumers Union ofUnited States, 466 U.S. 485, 498 & 501, 104S.Ct. 1949, 80 L.Ed.2d 502 (1984); see alsoAnderson v. Bessemer City, 470 U.S. 564,575, 105 S.Ct. 1504, 84 L.Ed.2d 518 (1985)(‘‘[R]eview of factual findings under theclearly-erroneous standard—with its defer-ence to the trier of fact—is the rule, notthe exception.’’); Pullman–Standard v.Swint, 456 U.S. 273, 287, 102 S.Ct. 1781, 72L.Ed.2d 66 (1982) (‘‘Rule 52(a) broadly re-quires that findings of fact not be set asideunless clearly erroneous.’’); United Statesv. United States Gypsum Co., 333 U.S.364, 394, 68 S.Ct. 525, 92 L.Ed. 746 (1948).

3. The question asked but not answered by thecourt which might have allowed it to cure itsself-inflicted wound was: ‘‘Question 7. Con-sistent with the Supreme Court’s decision inMarkman v. Westview Instruments, Inc., 517U.S. 370, 116 S.Ct. 1384, 134 L.Ed.2d 577(1996) and our en banc decision in CyborCorp. v. FAS Technologies, Inc., 138 F.3d 1448(Fed.Cir.1998), is it appropriate for this courtto accord any deference to any aspect of trialcourt claim construction rulings? If so, onwhat aspects, in what circumstances, and towhat extent?’’

4. Because some facts are so intertwined witha constitutional standard the Supreme Courthas held that de novo review is appropriate.For example, whether a defendant has actedwith actual malice in a defamation suit isreviewed de novo because, among other rea-sons, the scope of the First Amendment isshaped and applied by reference to such fac-tual determinations. Bose, 466 U.S. at 502,104 S.Ct. 1949 (‘‘[T]he content of the rule isnot revealed simply by its literal text, butrather is given meaning through the evolu-tionary process of common-law adjudica-tion.’’). Similarly, whether there is reason-able suspicion to conduct an investigatorystop or probable cause to perform a searchunder the Fourth Amendment are reviewedwithout deference. Ornelas v. United States,517 U.S. 690, 696, 116 S.Ct. 1657, 134L.Ed.2d 911 (1996) (holding that the protec-tions afforded by the Fourth Amendment are

‘‘fluid concepts that take their substantivecontent from the particular contexts in whichthe standards are being assessed’’). The rea-soning behind these limited exceptions surelydoes not apply to claim construction. Whileappearing from the perspective of this court’slimited sphere of influence to be dreadfullyimportant, claim construction does not impli-cate a constitutional value. Cf. Bose, 466U.S. at 502, 104 S.Ct. 1949 (‘‘[T]he constitu-tional values protected by the rule make it im-perative that judges—and in some casesjudges of [the Supreme] Court—make surethat it is correctly applied.’’). This is illus-trated by the fact that the outcome of a patentcase, unlike a defamation or illegal searchcase, has little impact on how future cases aredecided or on how future parties behave. Cf.id. at 501 n. 17, 104 S.Ct. 1949 (‘‘Regardingcertain largely factual questions in some ar-eas of the law, the stakes—in terms of impacton future cases and future conduct—are toogreat to entrust them finally to the judgmentof the trier of fact.’’). Even if claim construc-tion did implicate a constitutional value, it,unlike the decisions underlying the First andFourth Amendments, could readily be re-duced, when distinguished from its factualunderpinnings, to ‘‘a neat set of legal rules.’’Ornelas, 517 U.S. at 695–96, 116 S.Ct. 1657(quoting Ill. v. Gates, 462 U.S. 213, 232, 103S.Ct. 2317, 76 L.Ed.2d 527 (1983)).


Even those findings of fact based entirelyon documentary evidence are entitled todeference. Anderson, 470 U.S. at 574, 105S.Ct. 1504 (‘‘That [Rule 52(a) ] goes on toemphasize the special deference to be paidcredibility determinations does not alter itsclear command: Rule 52(a) ‘does not makeexceptions or purport to exclude certaincategories of factual findings from the obli-gation of a court of appeals to accept adistrict court’s findings unless clearly erro-neous.’ ’’ (quoting Pullman–Standard, 456U.S. at 287, 102 S.Ct. 1781)). In short, weare obligated by Rule 52(a) to review thefactual findings of the district court thatunderlie the determination of claim con-struction for clear error.

While this court may persist in the delu-sion that claim construction is a purelylegal determination, unaffected by under-lying facts, it is plainly not the case.Claim construction is, or should be, madein context: a claim should be interpretedboth from the perspective of one of ordi-nary skill in the art and in view of thestate of the art at the time of invention.See Multiform Desiccants, Inc. v. Med-zam, Ltd., 133 F.3d 1473, 1477 (Fed.Cir.1998) (‘‘It is the person of ordinary skill inthe field of the invention through whoseeyes the claims are construed.’’). Thesequestions, which are critical to the correctinterpretation of a claim, are inherentlyfactual. They are hotly contested by theparties, not by resort to case law as onewould expect for legal issues, but based ontestimony and documentary evidence.5

During so called Markman ‘‘hearings,’’which are often longer than jury trials,parties battle over experts offering con-flicting evidence regarding who qualifies asone of ordinary skill in the art; the mean-

ing of patent terms to that person; thestate of the art at the time of the inven-tion; contradictory dictionary definitionsand which would be consulted by theskilled artisan; the scope of specializedterms; the problem a patent was solving;what is related or pertinent art; whether aconstruction was disallowed during prose-cution; how one of skill in the art wouldunderstand statements during prosecution;and on and on. In order to reconcile theparties’ inconsistent submissions and ar-rive at a sound interpretation, the districtcourt is required to sift through and weighvolumes of evidence. While this courttreats the district court as an intake clerk,whose only role is to collect, shuffle andcollate evidence, the reality, as revealed byconventional practice, is far different.

Even if the procedures employed by thedistrict court did not show that it is engag-ing in factfinding, the nature of the ques-tions underlying claim construction illus-trate that they are factual and should bereviewed in accordance with Rule 52(a).For each patent, for example, who quali-fies as one of ordinary skill in the art willdiffer, just as the state of the art at thetime of invention will differ. These subsid-iary determinations are specific, multifari-ous and not susceptible to generalization;as such their resolution in one case willbear very little, if at all, on the resolutionof subsequent cases. See Ornelas, 517U.S. at 703, 116 S.Ct. 1657 (‘‘Law clarifica-tion requires generalization, and some is-sues lend themselves to generalizationmuch more than others.’’); Pierce v. Un-derwood, 487 U.S. 552, 561–62, 108 S.Ct.2541, 101 L.Ed.2d 490 (1988) (‘‘Many ques-tions that arise in litigation are not amena-

5. That most of the cases now appealed to thiscourt are ‘‘summary judgments’’ is irrelevant.We have artificially renamed findings of factas legal conclusions; the district courts havedutifully conformed to our fictional character-

ization, but this does not change the inherentnature of the inquiry. Of course, if the par-ties do not dispute the material facts, sum-mary judgment is appropriate.


ble to regulation by rule because theyinvolve multifarious, fleeting, special, nar-row facts that utterly resist generaliza-tion.’’ (quoting Maurice Rosenberg, Judi-cial Discretion of the Trial Court, Viewedfrom Above, 22 Syracuse L.Rev. 635, 662(1971))); Icicle Seafoods, Inc. v. Worthing-ton, 475 U.S. 709, 714, 106 S.Ct. 1527, 89L.Ed.2d 739 (1986) (rejecting de novo re-view of factual questions, even when out-come determinative). That the determina-tion of the meaning of a particular term inone patent will not necessarily bear on theinterpretation of the same term in a subse-quent patent illustrates this point; whilethe term is the same, the underlying factu-al context is different. It further provesthat these questions (e.g., who qualifies asone of ordinary skill in the art and whatwas the state of the art at the time ofinvention, among others) are implicitly be-ing determined in each case; because werefuse to acknowledge either their exis-tence or importance, however, the mannerof their resolution is never elucidated. Fi-nally, that claim construction is dependenton underlying factual determinations hasbeen verified by our experience, whichshows that reviewing these questions denovo has not clarified the law, but hasinstead ‘‘distort[ed] the appellate process,’’causing confusion among the districtcourts and bar. See Cooter, 496 U.S. at404, 110 S.Ct. 2447 (quoting Pierce, 487U.S. at 561, 108 S.Ct. 2541); see also Koonv. United States, 518 U.S. 81, 99, 116 S.Ct.2035, 135 L.Ed.2d 392 (1996).

Our purely de novo review of claim in-terpretation also cannot be reconciled withthe Supreme Court’s instructions regard-ing obviousness. While ultimately a ques-tion of law, obviousness depends on severalunderlying factual inquiries. Graham v.John Deere Co., 383 U.S. 1, 17, 86 S.Ct.684, 15 L.Ed.2d 545 (1966); see also Den-nison Mfg. Co. v. Panduit Corp., 475 U.S.809, 811, 106 S.Ct. 1578, 89 L.Ed.2d 817

(1986) (holding that Rule 52(a) requiresthat the district court’s subsidiary factualdeterminations should be reviewed forclear error); cf. Graver Tank & Mfg. Co.v. Linde Air Prods. Co., 336 U.S. 271, 275,69 S.Ct. 535, 93 L.Ed. 672 (1949) (holdingthat validity, while ultimately a question oflaw, is founded on factual determinationsthat are entitled to deference). ‘‘Under[section] 103, the scope and content of theprior art are to be determined; differencesbetween the prior art and the claims atissue are to be ascertained; and the levelof ordinary skill in the pertinent art re-solved.’’ Graham, 383 U.S. at 17, 86 S.Ct.684.

To a significant degree, each of thesefactual inquiries is also necessary to claimconstruction. Before beginning claim con-struction, ‘‘the scope and content of theprior art [should] be determined,’’ id., toestablish context. The ‘‘differences be-tween the prior art and the claims at issue[should] be ascertained,’’ id., to better de-fine what the inventor holds out as theinvention. And, the foundation for boththe obviousness and claim construction de-terminations is ‘‘the level of ordinary skillin the pertinent art.’’ Id.; see Multiform,133 F.3d at 1477. These underlying factu-al considerations receive the level of defer-ence due under Rule 52(a) when consider-ing obviousness, but they are scrutinizedde novo in the claim construction context.As directed by the Supreme Court, howev-er, it is especially important in the patentfield, ‘‘where so much depends upon famil-iarity with specific scientific problems andprinciples not usually contained in the gen-eral storehouse of knowledge and experi-ence,’’ to give deference to the districtcourt’s findings of fact. Graver Tank &Mfg. Co. v. Linde Air Prods. Co., 339 U.S.605, 609–10, 70 S.Ct. 854, 94 L.Ed. 1097(1950).


While the court flails about in an at-tempt to solve the claim construction ‘‘co-nundrum,’’ the solution to our plight isstraightforward. We simply must followthe example of every other appellate court,which, regarding the vast majority of fac-tual questions, reviews the trial court forclear error.6 This equilibrium did notcome about as the result of chance orpermissive appellate personalities, but be-cause two centuries of experience hasshown that the trial court’s factfindingability is ‘‘unchallenged.’’ Salve ReginaColl. v. Russell, 499 U.S. 225, 233, 111S.Ct. 1217, 113 L.Ed.2d 190 (1991); In-wood, 456 U.S. at 856, 102 S.Ct. 2182(‘‘Determining the weight and credibility ofthe evidence is the special province of thetrier of fact.’’). Time has similarly re-vealed that it is more economical for thedistrict court to find facts. Pierce, 487U.S. at 560, 108 S.Ct. 2541 (‘‘Moreover,even where the district judge’s full knowl-edge of the factual setting can be acquiredby the appellate court, that acquisition willoften come at unusual expense, requiringthe court to undertake the unaccustomedtask of reviewing the entire record TTTT’’).

Therefore, not only is it more efficientfor the trial court to construct the record,the trial court is better, that is, more accu-rate, by way of both position and practice,at finding facts than appellate judges.Anderson, 470 U.S. at 574, 105 S.Ct. 1504(‘‘The rationale for deference to the origi-nal finder of fact is not limited to thesuperiority of the trial judge’s position tomake determinations of credibility. Thetrial judge’s major role is the determina-tion of fact, and with experience on fulfill-ing that role comes expertise.’’); ZenithRadio Corp. v. Hazeltine Research, Inc.,

395 U.S. 100, 123, 89 S.Ct. 1562, 23L.Ed.2d 129 (1969). Our rejection of thisfundamental premise has resulted, not sur-prisingly, in several serious problems, in-cluding increased litigation costs, needlessconsumption of judicial resources, and un-certainty, as well as diminished respect forthe court and less ‘‘decisional accuracy.’’Salve, 499 U.S. at 233, 111 S.Ct. 1217. Weshould abandon this unsound course.7

If we persist in deciding the subsidiaryfactual components of claim constructionwithout deference, there is no reason whylitigants should be required to parade theirevidence before the district courts or fordistrict courts to waste time and resourcesevaluating such evidence. It is excessiveto require parties, who ‘‘have already beenforced to concentrate their energies andresources on persuading the trial judgethat their account of the facts is the cor-rect one,’’ to ‘‘persuade three more judgesat the appellate level.’’ Anderson, 470U.S. at 575, 105 S.Ct. 1504. If the pro-ceedings before the district court aremerely a ‘‘tryout on the road,’’ id. (quotingWainwright v. Sykes, 433 U.S. 72, 90, 97S.Ct. 2497, 53 L.Ed.2d 594 (1977)), as theyare under our current regimen, it is waste-ful to require such proceedings at all. In-stead, all patent cases could be filed in thiscourt; we would determine whether claimconstruction is necessary, and, if so, themeaning of the claims. Those few cases inwhich claim construction is not dispositivecan be remanded to the district court fortrial. In this way, we would at least elimi-nate the time and expense of the charadecurrently played out before the districtcourt.

Eloquent words can mask much mis-chief. The court’s opinion today is akin to

6. While jurisprudentially sound, the bar alsosupports this proposition, as evident by themany amici curiae briefs urging adherence toRule 52(a).

7. There are some scenarios where it is diffi-cult to weed facts from law, see Pullman–Standard, 456 U.S. at 288, 102 S.Ct. 1781, butclaim construction is not one of them.

1335NORTH AMERICAN CONTAINER v. PLASTIPAK PACK.Cite as 415 F.3d 1335 (Fed. Cir. 2005)

rearranging the deck chairs on the Titan-ic—the orchestra is playing as if nothing isamiss, but the ship is still heading forDavey Jones’ locker.

,

NORTH AMERICAN CONTAINER,INC., Plaintiff–Appellant,

v.

PLASTIPAK PACKAGING, INC., Amer-ican Bottling Company, Inc., CNCContainer, Kraft Foods, Inc., ShastaBeverages, Inc., the Kroger Company,and WIS–PAK Plastics, Inc., and Sil-gan Plastics Corporation, and TheClorox Company, and Reckitt Benck-iser Inc., and Barton Brands, Ltd., andAmerican National Can Group, Inc.,and Suiza Foods Corporation, andCoca–Cola Bottling, Co. Consolidated,Coca–Cola Enterprises, ContinentalPet Technologies, Inc., Owens–Illi-nois, Inc., Owens–Brockway PlasticProducts, Inc., Southeastern Contain-er, Inc., and Western Container Cor-poration, and Constar, Inc., AB–TexBeverage Corporation, and Dr. PepperBottling Company of Texas, and Al-bertson’s Inc., and Safeway, Inc.,Schmalbach–Lubeca Plastic Contain-ers USA, Inc., The Campbell SoupCompany, Knouse Foods Cooperative,Inc., and The J.M. Smucker Company,and UDV North America, Inc., andBCB USA Corp. (now known as CottBeverages, Inc.), and Tropicana Prod-ucts, Inc., and Heinz USA, and Col-gate–Palmolive Company, and ThePerrier Group of America, Inc., and

Quaker Oats Company, and DanoneInternational Brands, Inc., and GreatBrands of Europe, Inc., Defendants–Cross Appellants.

Nos. 04–1306, 04–1307.

United States Court of Appeals,Federal Circuit.

July 14, 2005.

Background: Patentee brought infringe-ment action against manufacturers anddistributors of blow-molded plastic bottles,alleging infringement of its reissue patentfor a plastic bottle. The United StatesDistrict Court for the Northern District ofTexas, granted summary judgment of non-infringement in favor of defendants, andpatentee appealed.

Holdings: The Court of Appeals, Lourie,Circuit Judge, held that:

(1) ‘‘generally convex’’ claim limitation inpatent covered inner walls that were‘‘slightly concave’’ and limited scope ofclaims to inner walls of the base por-tion with no concavity;

(2) ‘‘re-entrant portion’’ limitation of pat-ent included the lowermost points ofbottle’s inner walls, but did not includean added significant depth limitation;and

(3) reissue claims violated the recapturerule.

Affirmed in part, vacated in part, and re-manded.

1. Patents O226.6

Patent infringement analysis is a two-step process: first, the court determinesthe scope and meaning of the patent claimsasserted and secondly, the properly con-strued claims are compared to the alleged-ly infringing device.

Documents

PHILLIPS v. AWH CORP. 1303 - Berkeley Law States Court of Appeals, Federal Circuit. July 12, 2005. Background: Owner of patent for vandal-ism-resistant wall panels sued former dis-tributor