PRECAUTIONS TO BE TAKEN WHEN USING MULTILAYERjmaps/research/datasheets/... · 2. The main failures with multilayer piezoelectric actuators are deterioration of insulation resistance,

PRECAUTIONS TO BE TAKEN WHEN USING MULTILAYERPIEZOELECTRIC ACTUATORS(Please read these precautions before using our products)

1. Before using our products or designing a system using our products, readthe precautions and specifications (such as level of quality) for the productsyou intend to use on the last page of this manual.

2. The main failures with multilayer piezoelectric actuators are deterioration ofinsulation resistance, short-circuit, and open-circuit.

Before using the products, design systems carefully to ensure redundancy,prevention of the spread of fire, and prevention of faulty operation allowingfor the occurrence of failures.

3. Use the products after checking the working conditions and rated perform-ance of each of the multilayer piezoelectric actuator series.

Selection of AE series (a resin-coated type) or ASB, ASL series (a metal-sealed type) should be based on the intended working temperature andhumidity.

ISO 9001 ISO 14001

JQA JQA

JQA-0366 JQA-E-90094

CONTENTS

AE, AER series (resin coated type) ............................................................................. 3

ASB, ASL series (metal sealed type) ........................................................................... 8

Precautions to be taken when using products.......................................................... 13

Inquiries ........................................................................................................................ 21

2 Multilayer Piezoelectric Actuators Vol.1

Insulator

Internalelectrode

Externalelectrode

Ceramic

NEC TOKIN’s multilayer piezoelectric actuators are available in four series.

Resin-coated type

General-purpose

Metallic case type

High-powerGeneral-purpose

85˚C ratedAE seriesAER series

85˚C rated ASB series

150˚C rated ASL series

NEC TOKIN’s multilayer piezoelectric actuators were produced by our uniqueelement structure technology using ceramic materials with high electrostrictivefactors developed by NEC TOKIN.

FeaturesSpecial ceramics developed by NEC TOKIN are used in piezoelectric ceramic elements.As compared with conventional actuator elements, NEC TOKIN’s multilayer piezoelectric actuators havethe following advantages:

Advantages over electromagnetic actuatorsSuperior responseHigh resolution for positioningLow power consumptionNo electromagnetic noise

Advantages over bimorph piezoelectric actuatorsHigh energy conversion efficiency (around 7 times theenergy conversion efficiency of the bimorph type actua-tor), and low power consumptionLarge generated forceStable displacement, and reduced shift and creep phenomenaHigher response speed (more than 100 times the responsespeed of the bimorph piezoelectric actuator)

Advantages over stacked piezoelectric actuatorsCompact (less than 1/10 the specific ratio of the stackedpiezoelectric actuator)Low drive voltage, and ease of useInexpensive

Structure of NEC TOKIN’s MultilayerPiezoelectric Actuator

*AE series is resin-coated products. Therefore we recommend metallic case type, ASB or

ASL series in high humidity condition.

Multilayer Piezoelectric Actuators Vol.1 3

AE, AER Series (Resin coated type)

OutlineThe multilayer piezoelectric actuator is a ceramicelement for converting electrical energy into me-chanical energy such as displacement or force utilizingthe piezoelectric longitudinal effect.By taking full advantage of its superior features suchas ultrafine drive, high efficiency, and high power,for example, users can look forward to a drivesource for finely positioning a variety of apparatuseswith accuracy.

Features Applications Large generated force : 350Kg/cm2 (Typ.) Heads for dot printers and ink jet printers, auto- High-speed response : Driving up to about tracking of magnetic heads, valve drive, position-

1/3 of self resonant frequency is possible ing of mirror priss, linear motors for camera auto Accurate positioning : Position control on the focusing, pumps, vibration of parts feeder, pre-

order of nanometers is possible ssure sensors for touch panel input apparatus. Low power consumption : Electro-mechanical

conversion efficiency of 65% (Typ.) Ultraminiature : 1/10 of a conventional multi-

layer actuator (specific volume) Noiseless

Outline and Marking

Note:Factory-shipped polarization : Red lead wire = (+), white lead wire = (-)Coating : Epoxy resin

T1

T2

W1

H

1A007

(+) (–)

W2

AE Series (Square rod type)


Numbering SystemExample AE 0505 D 16

Nominal displacement : unit, micrometers [µm]Example : 16 = 16µm

DisplacementDimensions of cross section : unit, millimeters [mm]

Example: 0505=5mm × 5mmSeries Name : AE = resin coated

Manufacturing Lot No.Example 00 E 001

1 Lot serial number for each month of manufacture2 Symbol representing month of manufacture (A=January)

3 Numerals showing the year of manufacture by two trailingdigits of Gregorian calendar year (00: 2000) or by the last digitfor a product manufactured in or before 1999 (9: 1999).

Performance

Model Number T1 W1 H T2 W2

AE0203D08 2±0.1 3±0.1 10±0.1 3.5max. 4.5max.AE0203D16 2±0.1 3±0.1 20±0.1 3.5max. 4.5max.AE0505D08 5±0.1 5±0.1 10±0.1 6.5max. 6.5max.AE0505D16 5±0.1 5±0.1 20±0.1 6.5max. 6.5max.AE1010D16 10±0.1 10±0.1 20±0.1 11.5max. 11.5max.AE1414D16 14.2±0.1 14.2±0.1 20±0.1 15.7max. 15.7max.

AE0203D08 AE0203D16 AE0505D08 AE0505D16 AE1010D16 AE1414D16Part Number

Item(Note 1)

(Note 2)

(Note 3)

(Note 4)

(Note 5)

(Note 5)

Operating temperature range (°C)Maxximum drive voltage (VDC)Recommended drive voltage (VDC)Displacement (µm)Displacement (µm) Insulation rasistance (MΩ) min.Capacitance (µF)Dissipation factor max.

–25~+85150100

9.1±1.56.1±1.5

1000.18±20%

0.035

17.4±2.011.6±2.0

500.35±20%

0.05

9.1±1.56.1±1.5

500.75±20%

0.05

17.4±2.011.6±2.0

101.4±20%

0.05

18.4±3.512.3±3.5

55.4±20%

0.05

18.4±3.512.3±3.5

210.8±20%

0.05

Symbol A B C D E F G H J K L M

Month 1 2 3 4 5 6 7 8 9 10 11 12

Model Number φd* φD* rrrrr*

AE0203D08 0.3 0.5 100

AE0203D16 0.3 0.5 100

AE0505D08 0.3 0.5 100

AE0505D16 0.5 0.8 100

AE1010D16 0.5 0.8 100

AE1414D16 0.5 0.8 100

Outer Dimensions

* Typ.

Note 1: The operating temperature is equal to the temperature of the actuator element when the element is driven with d.c. voltage. When the actuatorelement is driven with a.c. voltage, allow for a rise in temperature resulting from superimposed heat caused by dielectric loss to the operatingtemperature.

Note 2: Displacement resulting from applying the maximum drive voltage to the actuator element. Note 3: Displacement resulting from applying a recommended drive voltage (100V) to the actuator element. Note 4: DC150VDC obtained in 1 min Note 5: f=1kHz, 1Vr.m.s.

l

φd

φd

Dφ

φ D

= Diameter of lead wire

= Outer diameter including the thickness of coating

= Length of lead wirel


AE0203D08 AE0203D16 AE0505D08 AE0505D16 AE1010D16 AE1414D16Model number

Item(Note 1)

(Note 2)

(Note 3)

(Note 3) 10 10 10 10 10 10

Generated force (compression force) (N)Pesonance frequency (kHz)Tensile strength (N)Young’s modulus (N/m2)

200 13820

4.4×10

2006920

4.4×10

850 138100

4.4×10

850 69

1004.4×10

3500 69

4004.4×10

7000 69

8004.4×10

0

0 20 40 60 80 100

10

20

30

0

50

100

150

Vol

tage

(V

)G

ener

ated

dis

plac

emen

t (µ

m) Measured temperature : 23°C

(with use of unpolarized element)AE0505D16

Time (sec)

Unpo-larized

Unpo-larized

500

10

20

30

40

100 150

Measured temperature : 23°C(with use of unpolarized element)AE0505D16

Voltage (V)

Gen

erat

ed d

ispl

acem

ent (

µm

)

Characteristics

Note 1: See Fig. 3. In the drawing, F0 is called a generated force (compression resistance). The values are representative values obtained under thetest conditions of NEC TOKIN.

Note 2: The actuator element has both ends opened. The values are representative values obtained under the test conditions of NEC TOKIN. Note 3: The values are representative values obtained under the test conditions of NEC TOKIN. Note 4: See Fig. 3. The values are obtained by applying 150VDC to the actuator elements. These values are representative values obtained under the

test conditions of NEC TOKIN.Fig. 1 Voltage and Generated Displacement vs Time CharacteristicsFig. 2 Voltage vs Generated Displacement CharacteristicsFig. 3 Generated Force vs Generated Displacement Characteristics (Hysteresis characteristics between generated displacement and generated force)Fig. 4 Temperature Characteristics of Generated Displacement (Variations in displacement generated by the actuator element corresponding to

variations in ambient temperature)Fig. 5 Heat Development Characteristics (Variations in temperature of generated heat with time when a d.c. voltage having half the crest value of a sine

waveform is superimposed on the sine waveform.)Fig. 6 Heat Generation vs Frequency Characteristics

Fig. 1 Voltage and generated displacementvs time characteristics

Fig. 2 Voltage vs generated displacementcharacteristics


Fig. 4 Temperature characteristics ofgenerated displacement

Fig. 3 Generated Force vs GeneratedDisplacement Characteristics

Fig. 6 Heat generation vs frequencycharacteristics

Fig. 5 Heat development characteristics

20

10

150 VDC

F0

0V, open element

0V, shorted element

–10

–20

0500 1000

20

18

16

14

12

10

8

6

4

2

–50 0 50 100 2001500

AE0203D08(measuring 2×3×10mm element)

0 75 150

Measured temperature : 25±5°C(with use of polarized element)AE0505D16

Generated force (N)Temperature (°C)

Iγ + I150

Iγ (residual displacement)

I150 Drive voltage (V)

Gen

erat

ed d

ispl

acem

ent (

µm

)

Gen

erat

ed d

ispl

acem

ent (

µm

)

Ihys

I150

Ihys

Iγ

DC 75V superimposed on SIN waveform (150V)AE0505D16

80

70

60

1 kHz

500 Hz

100 Hz

50 Hz

200 Hz

50

40

30

20

10

0 100 200

100

80

60

40

20

10 100 1000

300

AE0505D16After passage of 5 min

40 V

100 V

150 V

20 V

50 V

75 V

Hea

t gen

erat

ion

T (

°C)

Time (sec)

AC frequency (Hz)

Amplitudeof a.c. DC bias Symbol

Hea

t gen

erat

ion

T (

°C)


Item Performance Test Conditions

Temperature cycle test

a. Displacement : less than (intial value±20%)b. Capacitance : less than (intial value±30%)c. tan δ : less than intial rated valued. IR : more than 1MΩ e. Appearance : without noticeable defectiveness

Room temperature (3min) –25°C (30min) room temperature (3min) +85°C (30min)Number of cycle : 10 cycles

Note that the reliability of our products are dependent on the environment (particularly ambient humidity).

Note: Unless otherwise specified, tests are conducted in compliance with JIS C 5102 (method for testingfixed capacitor for use in electronic equipment).

Environmental Perfomance

AER Series (Ring type)Ring type

FeaturesInternal space can be utilized

SpecificationsPart Mumber

Item

Displacement (µm)

Insulation Resistance (MΩ)

Capacitance (µF)

Item (kg • f)

AER13.6 × 10 × 20

15.6 ± 2 at 150V

More than 5 DC150V (value per minute)

3.2 ± 20%

220 typ.

Because AER series are custom-made products, the productshown above is an example. Please consult us separately about

size or data-sheet.


ASB, ASL Series (Metal sealed type)

OutlineMultilayer piezoelectric actuators convert electricalenergy into mechanical displacement energy.Associated with technical innovation of a source fordriving mechatronics such as a source for finelydriving a semiconductor manufacturing apparatuswith accuracy, the multilayer piezoelectric actuatorsare application in a variety of fields.NEC TOKIN’s metal sealed multilayer piezoelectricactuators have achieved success in ensuring alonger lifetime and higher performance.

Features ApplicationsEasily integrated into equipment because Driving of X–Y table for a stepperthe element is sealed in a metal case Driving of valve at the time of high-speed(the actuator with a flange) precision flow rate control of gases, or fluidsLow-voltage drive: Maximum drive voltage Control of ink thickness in offset printingof 150V machinesFive types of displacement variation; 17, 34, Control of extruded plastic film thickness51, 68 and 170[µm] Fine adjustment of laser beam receivingGenerated force : 800[N] (=80[Kgf]) mirrorsAllows high-speed fine driveNo rubbing portions

. .

φ19.6±0.5

19±0.59±0.2

2.5±0.2

17

M4 screw of min. 3 deepPrepared hole of max. 5 deep

2

130±10L±0.5

ASB001A

2A001

[mm]

Mark

11.5±0.5Section A

φ

17TOP VIEW

BOTTOM VIEW

Enlarged cross-section of section A (4/1)

Details of mark

←Product code

←Manufacturing lot No.

ASB Series (85-resistance) ASL Series (150-resistance)

Part Number Product code Part Number Product code L [mm]

ASB170C801NP0 ASB001A ASL170C801NP0 ASL027 38.4




ASB171C801NP0 ASB050 218.8

Outer Dimension and MarkingFemale thread type (N-TYPE)


13±0.5

3.0±0.2

2.5±0.2

2

130±10

P.C.D.28

L±0.5

ASB007A

2A001

[mm]

Mark

11.5±0.5Section A

φ

17

TOP VIEW

BOTTOM VIEW

35±0.5φ

45°45°

Enlarged cross-section of section A (4/1)

Details of mark

←Product code

←Manufacturing lot No.

19.6

±0.5

φ

4– 3.5φ

Example AS B 170 C 801 N P 0New Design No. Sequentially numbered, starting at

0Configuration of drive section P=planeConfiguration of mount N=female thread typesection F=flange typeGenerated force Unit: Newton [N]

First two figures are effectivenumbers.Last figure is an exponent of 10.Example: 801=800N=80 Kgf

Maximum drive voltage C=150VNominal displacement Unit; micrometers [µm]

First two figures are effectivenumbers.Last figure is an exponent of 10.Example: 170=17µm

Construction of housing, B=bellows + preloadand operating temperature Maximum operating temperaturerange of 85°C

L=bellows + preloadMaximum operating temperatureof 150°C

Series Name AS=encapsulated in metal case

Part Number Product code Part Number Product code L [mm]

ASB170C801FP0 ASB007A ASL170C801FP0 ASL037 32.4




ASB171C801FP0 ASB051 212.8

Flange type (F-TYPE)

Numbering System


Manufacturing Lot No.Example 00 A 001

1 Lot serial number for each month of manufacture2 Symbol representing month of manufacture (A=January)

3 Numerals showing the year of manufacture by two trailingdigits of Gregorian calendar year (00: 2000) or by the last digitfor a product manufactured in or before 1999 (9: 1999).

Standard Part and Performance

Symbol A B C D E F G H J K L M

Month 1 2 3 4 5 6 7 8 9 10 11 12

Item

s Shape of mount

Female screw type (N - TYPE)

Flange type (F - TYPE)

Operating temperature range (°C)

Maximum drive voltage (VDC) 150

Recommended Drive Voltage*1 (VDC)

Displacement at maximum voltage (µm)

Displacement at recommended voltage (µm)

Hysteresis

Generated force (compression resistance) (N)*2

Resonance frequency (kHz)*3

Capacitance (C) (µF)*4

Dissipation factor (tan 8)*4

Insulation resistance (IR) (MΩ) min.*5

Withstand voltage (TV) (VDC)

Sealing propeties

Part Number

ASB170C801NP0 ASB340C801NP0 ASB510C801NP0 ASB680C801NP0 ASB171C801NP0 ASB170C801FP0 ASB340C801FP0 ASB510C810FP0 ASB680C801FP0 ASB171C801FP0 –25~+85

100

17.0±3

12.0±3

14

1.5±20%

30

34.0±6

24.0±6

12

3.0±20%

15

51.0±9

36.0±9

Less than 15% of generated displacement

800(=80[Kgf])

10

4.5±20%

Less than 0.05

10

165 No abnormality observed after application of voltage for one min.

Less than 1 × 10–8 atm. cc/sec.

68.0±12

48.0±12

8

6.0±20%

5

170±30

120±30

3

1.5±20%

Less than 0.2

1

..

Note 1. *1 : Voltage at the maximum drive temperature (85°C).Note 2. *2 : At 150 VDC The values are representative values obtained under test by NEC TOKIN.Note 3 *3 : The actuator element has both ends free; the values are representative values

obtained under test by NEC TOKINNote 4. *4 : f=1kHz, 1Vr.m.s.Note 5. *5 : 150VDC, Value obtained in one min.Note 6. Unless otherwise specified, standard measuring environments are as follows.

• Temperature : 23 ± 5°C• Humidity : 65 ± 15°C

Item

s Shape of mount

Female screw type (N - TYPE)

Flange type (F - TYPE)

Operating temperature range (°C)

Maximum drive voltage (VDC) 150

Recommended Drive Voltage*1 (VDC)

Displacement at maximum voltage (µm)

Displacement at recommended voltage (µm)

Hysteresis

Generated force (compression resistance) (N)*2

Resonance frequency (kHz)*3

Capacitance (C) (µF)*4

Dissipation factor (tan 8)*4

Insulation resistance (IR) (MΩ) min.*5

Withstand voltage (TV) (VDC)

Sealing propeties

ASL170C801NP0 ASL340C801NP0 ASL510C801NP0 ASL680C801NP0 ASL170C801FP0 ASL340C801FP0 ASL510C810FP0 ASL680C801FP0

17.0±3

12.0±3

14

1.12±20%

30

34.0±6

24.0±6

12

2.23±20%

15

51.0±9

36.0±9

10

3.35±20%

10

68.0±12

48.0±12

8

4.47±20%

5

..

–40~+150

150

100

Less than 15% of generated displacement

800(=80[Kgf])

Less than 0.05

165 No abnormality observed after application of voltage for one min.

Less than 1 × 10–8 atm. cc/sec.

Part Number

ASB series

ASL series


Item Performance Test Conditions

a. Displacement : Less than (initial value ±30%) ASB : Room temperature (3min) → –25°C (30min)b. Capacitance : Less than (initial value ±30%) → room temperature (3min)→ +85°C (30min)

1. Temperature cycle test c. tan δ : Less than initial rated value ASL : Room temperature (3min) → –40°C (30min)d. IR : More than 1MΩ → room temperature (3min)→ +150°C (30min)e. Appearance : Defect free Number of cycles : 10 cycles

a. Displacement : Less than (initial value ±30%) Temperature ASB : 85±2°Cb. Capacitance : Less than (initial value ±30%) ASB : 150±2°C

2. High-temperature shelf test c. tan δ : Less than initial rated value Time : 1,000±48hd. IR : More than 1MΩe. Appearance : Without noticeable defectiveness

a. Displacement: Less than (initial value ±30%) Solvent : isopropyl alcoholb. Capacitance : Less than (initial value ±30%) Temperature : 23±5°Cc. tan δ : Less than initial rated value Time : Immersed in 1 mind. IR : More than 1MΩe. Appearance : Without noticeable defectivenessf. Mark : Easily legible

a. Displacement : Less than (initial value ±30%) Temperature : 150±3°Cb. Capacitance : Less than (initial value ±30%) Time : 96±4 hc. tan δ : Less than initial rated valued. IR : More than 1MΩe. Appearance : Without noticeable defectivenessf. Mark : Easily legible

←←←

4. Heat resistance test

3. Solvent resistance test

70

60

50

40

30

20

10

0 50

10

20

30

40

50

60

100

100 1000100 150

ASB170C801*P0

ASB340C801*P0

ASB510C801*P0

ASB340C801*P0

ASB170C801*P0

ASB510C801*P0

ASB680C801*P0

Voltage vs Displacement Drive frequency vs Displacement

Drive frequency (Hz)DC voltage (V)

Dis

plac

emen

t (µ

m)

Crest value of voltage150V (SIN waveform)DC bias : 75V

Dis

plac

emen

t (µ

m)

0

10

20

30

40

50

60

70

800 1000600400200

ASB340C801*P0

ASB170C801*P0

ASB680C801*P0ASB510C801*P0

Compression load vs Displacement

Generated force (N)

Applied voltage 150VDC

Dis

plac

emen

t (µ

m)

Environmental Performance

Note 1 : Unless otherwise specified, tests are conducted in compliance with JIS C 5102 (method for testing fixed capacitor for use in electronic equipment).

Data on Features

0 50

106

107

108

109

1010

5–25 –15 –5 105 12525 6545 85100 150

1

2

3

4

5

6

–20 0 20 40 60 800

10

20

30

40

50

60

ASB170C801*P0

ASB340C801*P0

ASB510C801*P0

ASB510C801*P0

ASB170C801*P0

ASB170C801*P0

ASB340C801*P0

ASB510C801*P0

Temperature vs Displacement DC bias vs Capacitance

DC bias voltage (V)

Temperature vs Insulation resistance

Temperature (°C) Temperature (°C)

Applied voltage 150VDCMeasured voltage : 150VDC

Measured frequency : 1kHz

Dis

plac

emen

t (µ

m)

Cap

acita

nce

(µF

)

Insu

latio

n re

sist

ance

(Ω

)

ASB series (Enter N or F in * of part number)

← ←←


Applications System for minutely driving a variety of control and machining apparatuses used in mechatronics at high

speed (semiconductor device manufacturing apparatus) System for minutely driving a light-receiving mirror used for laser communications between communica-

tions satellites and between communications satellites and ground stations in the field of communications

X-Y stagePressure microcontrol for thin-film hardnessmeasurement

Various types of fine film-thickness controlFine adjustment of mirror and lens of opticalmeasuring instrument

DC servomotory

piezoelectric actuator

Fine adjustmenttable

Rough adjustmenttable

PTFE sliderBase

Y X

Displacementsensor

SamplePresser

Sample panElectronic digital balance

Micrometer

Multilayerpiezoelectricactuator

Multilayerpiezoelectricactuator

Multilayer piezoelectricactuator

Blade

Blade

Take-upreel

Sheet

Thick control of film forming machine

Ink thickness control of printing machine

Ink

Transfer roller

Ink feed roller

Total reflection mirror

Incoming laser light

Interference fringe detector

Multilayer piezoelectricactuator

Half mirror Sample

Displacement

Michelson’s interferometer

ASL series (ASB VS. ASL) (Enter N or F in * of part number)

ASB Type

ASL Type

2500

2000

1500

1000

500

0

-40 -20 0 20 40 60 80 100 120 140 160

Cap

acita

nce

(nF

)

Temperature (˚C) SAMPLE:5×5×20mm

Temperature vs. Capacitance

-40 -20 0 20 40 60

60

50

40

30

20

10

0

80 100 120 140 160

Temperature(˚C)

Temperature vs.Displacement

Dis

plac

emen

t(µ

m)

ASL510C801***

ASB510C801***

Examples of applications of NEC TOKIN’s multilayer piezoelectric actuator


Precautions to be taken when usingmultilayer piezoelectric actuators

This section relates to handling precautions to maintain the function of multilayer piezoelectric actuators.Please read and note all these precautions before using our products.The user is required to ensure appropriate storage of a multilayer piezoelectric actuator, circuit designsuitable for the intended use of the actuator, evaluation, mounting, and test so that the piezoelectric actuatorcan perform its function.In the event of any problems resulting from improper storage, circuit design, evaluation, mounting, or test ofthe actuator, NEC TOKIN assumes no responsibility for those problems.

1. Circuit Design(1) Prediction of Field Failure Rate

RELIABILITYNEC TOKIN has made every effort to improve the reliability of the multilayer piezoelectric ceramic actuatorin a variety of environments. During the course of study of the improvements, it has became evident thathigher reliability of the actuator can be assured by derating drive voltage, ambient temperature, and relativehumidity.

CONCEPT FOR RELIABILITY (ASB series)1) MTTF

Reliability of our products is represented by MTTF (Mean Time To Failure).MTTF has the following meanings. (Quoted from JIS Z 8115)MTTF: Mean time to failureMeaning: Mean time to failure of non-repaired system, equipment, or part

MTTF of ASB series : 36,000 hrs.Conditions : 1 Drive voltage 100VDC, 2 Ambient temperature 85°C

* This MTTF value is used as a reference for estimating an MTTF that will be obtained under actual conditions.

2) Acceleration Factor of Our Products

2)-1. Acceleration factor [Av] with respect to drive voltageAv= (100 [V]/Vr)2 .....(1), Vr: Actual drive voltage

2)-2. Acceleration factor [At] with respect to ambient temperature85 [°C] – Tr

10Tr : Actual ambient temperature

3) Estimation of MTTF under actual conditions

Where the acceleration factors relating to drive voltage and ambient temperature are taken into account,MTTF is computed by the following expression:

MTTFr = MTTFs × Av × At ..... (3)

Example MTTF is computed under the following conditions:

1 Drive voltage : 150VDC MTTFr : Estimated MTTF2 Ambient temperature : 60°C MTTFs : Reference MTTF

(36,000 hrs are used for reference MTTF in this calculation.)

At= 1.5x......(2), x = ...... (2)’


. .

∴

85 [°C] – 60 [°C]10

. .

40–Tr

10

40–2510

From expression (1), Av = (100 [V] /Vr)2 = (100 [V] /150 [V])2 = 0.444

From expression (2), At = 1.5x = 1.52.5 = 2.75 × = = 2.5

Therefore, from expression (3),MTTFr = 36,000 [hours] × 0.444 × 2.75 = 44,000 [hours]

*Note : The MTTF and the calculation example are obtained for reference under the definite test conditions of NEC TOKIN.Therefore, the MTTF is not guaranteed under wide-ranging drive conditions likely to be obtained if our products are usedtogether with user’s systems.

CONCEPT FOR RELIABILITY (AE series)1) MTTF

Reliability of our products is represented by MTTF (Mean Time To Failure).MTTF has the following meanings. (Quoted from JIS Z 8115)MTTF : Mean time to failure, that is, mean time to failure of non-repaired system, equipment, or part

MTTF of AE series : 500 hrs.Conditions : q Drive voltage 150V

w Ambient temperature 40°C * These parameters are representative data ofe Relative humidity 90 to 95%RH AE0505D16 in 1990.

The above MTTF is called MTTFs and used as a reference for estimating an MTTF that will be obtainedunder actual conditions. This MTTF is obtained under the most hostile conditions at present, and thisvalue is selected for obtaining a lot of information items in a short period of time. In other words, theMTTFs is obtained under accelerated conditions.

2) Acceleration factor of our products (acceleration factors obtained under conditions q to e with respectto actual conditions)

Acceleration factor [Av] with respect to drive voltageAv= (150/Vr)3.2 (1), Vr : Actual drive voltage (DC)

Acceleration factor [Ah] with respect to relative humidityAh - (90/Hr)4.9 (2), Hr : Relative humidity when actuator is actually used (RH%)

Acceleration factor [At] with respect to ambient temperature

At= 1.5 (3), Tr : Ambient temperature when actuator is actually used (°C)

3) Estimated MTTF obtained under actual conditions

Where the acceleration factors relating to drive voltage, relative humidity, and ambient temperature aretaken into account, MTTF is computed by the following expression:

MTTFr = MTTFs × Av × Ah × At (4), where MTTFr is an estimated value,and MTTFs is a reference value = 500 hrs.

4) Example of calculation (MTTFr obtained under derated actual conditions)

MTTF is computed, provided that 100 VDC is continuously applied to an actuator inenvironments of 25°C and 60%RH.MTTFr = 500 × (150/100)3.2 × (90/60)4.9 × 1.5 = 24,500 hrs.

For reference, Fig. 7 shows a nomogram provided for quick calculation of MTTFr under derated actualconditions.

*Note : The above mentioned MTTF and acceleration equation are obtained for reference under the definite test conditions of NEC TOKIN.Therefore, they are not guaranteed under wide-ranging drive conditions likely to be obtained if our products are used together with user’ssystems. Further, please remember that the degree of reliability varies depending on the size of the actuator.


The following nomogram shows an exampleof an actuator used under the following condi-tions:Ambient temperature 40°C (T)

150 150Vr 100

Actual relative humidity ratio90 90Hr 60

From the drawing, the magnifyingfactor of MTTF is F = 26. Therefore,an estimated MTTF isMTTFr = 500 × 26 = 13,000 hr.Note: In the case of MTTFs = 500 hr.

This nomogram is plotted by takingMTTFr = MTTFs × (150/Vr)3.2 × (90/Hr)4.9 × 1.5 as

F = MTTFr/MTTFs = (150/Vr)3.2 × (90/Hr)4.9 × 1.5 .Use of this nomogram allows you to quickly find anestimated MTTFr.

Fig. 7 Nomogram for MTTFr

(1) How to use the nomogram

q Draw a line q between the drive voltage ratio and the relative humidity ratio corresponding toconditions to find an intersection P1 with the axis t0.

w Draw a line w between the point P1 and an ambient temperature when the actuator is used. Anintersection between the line w and the axis F is a magnifying factor of MTTF. In other words,MTTFr = MTTFs × F.

If a multilayer piezoelectric actuator element is constantly operated at a high frequency, theactuator element generates heat, resulting in higher temperature of the element. In the event thatthe temperature of the actuator element becomes higher, the insulation resistance of the actuatorelement is degraded, which may cause failures. To avoid the failures, use the actuator elementwithin the maximum operating temperature taking into account the heat developing in the element.

Note that the reliability of the AE series is largely dependent on ambient conditions (particularlyhumidity).

(2) Frequency

NEC TOKIN’s multilayer piezoelectric actuators should be used within less than 1/3 of their self-resonance frequencies.

(3) Response Characteristics

Abrupt rise and fall of the voltage applied to the actuator brings about ringing in generated displacementas shown below, and a tensile force is exerted on the actuator element. Intensive ringing may cause

Drive voltage ratio = = = 1.5 (V)

= = = 1.5 (H)

40–Tr

10( )

40–Tr

10( )

P1

1

2

2.0

1.8

1.6

1.4

2.4

2.2

2.0

1.8

1.6

1.4

1.2

1 1

2

4

7

2

10

4

7102

2

4

7

103

2

4

7

104

1.2

1V H F

T20

30

40

50

60

70

80

t0

Max

imum

Driv

e V

olta

ge/A

ctua

l Driv

e V

olta

ge

Max

imum

Rel

ativ

e H

umid

ity/A

ctua

l Rel

ativ

e H

umid

ity

Mag

nify

ing

Fac

tor

of M

TT

F

Am

bien

t Tem

pera

ture

(°C

)


mechanical breakage of the actuator element. To prevent this, the rise or fall of the applied voltageshould be kept within less than 1/3 of the resonance frequency of the actuator element.

Ringing is a phenomenon in which an over-shoot temporarily develops in the displace-ment of the actuator and eventually the actuatorcauses vibration and constriction when abruptrising or falling of an applied voltage occurs.

The actuation of the piezoelectric actuator is similar to the injection of electric charges into a relativelylarge capacitor. A large electric current is necessary to realize high-speed response of the actuator.An estimate of a drive current is obtained in the same manner as in the case of a capacitor.

Q=CV (C : capacitance, V : drive voltage)Q=Ilt (I : Drive current, t : rise time)

∴I=CV/t

For example, if AE0203D08 (Cap=0.18µF) isactuated in the manner as shown in the followingdiagram, a current of about I = (0.18×150)/15= 1.8(A) becomes necessary. A much largercurrent may flow when the actuator element isactually driven, and therefore allowance shouldbe made for current limitations of the powersource.

2. Drive(1) Connect the red lead wire to the positive terminal of the power supply.

(2) If a multilayer piezoelectric actuator is exposed to high temperatures above 100°C, the actuator shouldbe used after being polarized. The actuator should be polarized using the following circuit configurationunder conditions as shown below. Further, if the actuator element is polarized, shift characteristics ofthe element become smaller.

* Drive the actuator element by way of aresistor of about 1kΩ so as to avoid abruptrise and fall of the voltage applied to theactuator.

* Polarization conditions : Application of 0V → 150V±0.2V → 0V(retained more than 10 sec.)

(3) Do not apply excessive voltage to the actuator, as this may cause mechanical fracture or result inreduced reliability.

Time

Voltage

Displacement

Dis

plac

emen

t

Voltage

150

15µsec t (µsec)

Vol

tage

R1

VPA

R2

S

Protective resistor R1Discharge resistor R2

= 1 kΩ= 1 kΩ


3. Working Environment3-1. AE series(1) Do not operate the actuator element with a d.c. voltage or an a.c. voltage having a frequency as small

as several hertz when it is placed in a moist or highly humid environment, in order to prevent migrationand insulation degradation resulting from migration.

(2) Do not use the actuator element in a high concentration of highly flammable gas. In the event theactuator element becomes degraded, the gas may ignite.

(3) It is necessary to compensate the temperature of the actuator element allowing for its expansion andcontraction owing to thermal expansion in the environment where temperature variations are encoun-tered.

3-2. ASB series, ASL series(1) Although ASB series actuators are usable under highly humid conditions, a circuit using the actuator

element should be carefully designed to ensure redundancy and prevention of faulty operation.

(2) Terminal electrodes around the mounts of our products are unprotected. Extreme caution and safestructure design of a system are required to use the actuator in a high concentration of highly flammablegas.

(3) It is necessary to compensate the temperature of the actuator element allowing for its expansion andcontraction owing to thermal expansion in the environment where temperature variations are encoun-tered.

4. Mounting of Multilayer Piezoelectric Actuator(1) Use the actuator so as not to cause flexing, twisting, or tension. Further, use the actuator while the

center axis of mechanical load used for driving the actuator is aligned with the center axis ofdisplacement of the actuator.* Reference : Guide for tolerance of twisting and tension

(2) Since ceramics are vulnerable to tension, they may break on receiving tension. Mechanical fracture ofthe actuator element is effectively prevented if it is used in a prestressed state.A force which is about one-half of a generated force (compression resistance) is suitable for use as aprestress exerted on the actuator element.

(3) Epoxy-based adhesives are usable for bonding AE series multilayer piezoelectric actuators. If thebonding of the actuator element involves heat treatment, it is necessary to prevent a large difference incoefficient of thermal expansion from arising between the actuator element and a member to which theactuator element is bonded. Otherwise, thermal stress resulting from the difference in thermalexpansion coefficient would break the actuator element.Further, the actuator element must be polarized after it has been subjected to heat treatment .

(4) In case of the ASB series, ASL series of piezoelectric actuator elements, please attach a drive memberto a displacement-generating end of the actuator element after having mounted the actuator element.

5. Handling and Storage Precautions(1) Avoid excessive physical shock resulting from, for example, dropping. An internal piezoelectric ceramic

element may break as a result of cracks.

(2) Avoid excessive tension exerted on a lead wire. Please do not pick up or move the lead wire.

Allowable compression stress appliedto an actuator which generates a forceof 800[N]

Twisting force Less than 3 × 10–1N•m (or less than 3Kgf·cm)

Tension Less than 50N (or less than 5Kgf)


(3) Machining of the actuator element and replacement of the lead wire are prohibited.

(4) Do not handle the AE series of piezoelectric actuator elements with bare hands; otherwise, thereliability of the actuator element would be degraded.

(5) For the ASB series, ASL series of piezoelectric actuator elements, do not pinch or press bellows (anexpandable crimping cylinder) of the actuator element using a pair of pliers or other tool. The bellowshas a thickness of only 0.15mm.

(6) Neither the AE series nor the ASB series, ASL series of piezoelectric actuator elements should bedisassembled. In particular, the AE series, ASL series of piezoelectric actuator elements are filled withinactive gas for protecting the element, and a multilayer piezoelectric actuator element is encapsulatedin a metal case.

(7) Do not cleanse the AE series of piezoelectric actuator elements with organic solvent. Otherwise, theouter plastic jacket of the actuator element will be damaged by the solvent, resulting in degradedreliability.

(8) Store the AE series of multilayer piezoelectric actuators in a dry atmosphere (preferably below40%RH). The storage temperature should be kept as close to ordinary temperatures (–5~+40°C) aspossible.

(9) Store the ASB series, ASL series of multilayer piezoelectric actuators at temperatures which are asclose to ordinary temperatures (–5~+40°C) as possible and at a humidity of less than 80%RH.

(10) Store the actuators where there is no vibration.

(11) Repolarize the actuators when they are used after having been stored for a long period of time (morethan about three months).

(12) Since the actuator elements use a high voltage, be careful to avoid electric shock.

6. Others(1) It is possible to improve the reliability of the AE series of multilayer piezoelectric actuators by

encapsulating them in a metal case to seal out moisture.

(2) If the AE series actuator elements are activated with a.c. or pulse voltage, a resulting inductive losscauses them to generate heat, which in turn prevents the intrusion of moisture from the outside throughthe outer jacket. Such a drive method makes for better reliability of the actuator elements.

Conversion of Units between SI unit system and MKS unit systemUnit of force : 1Kgf = 9.80665NPressure : 1Kgf/mm2 = 9.80665 × 106Pa = 9.80665N/mm2

Moment of force : 1Kgf•m = 9.80665N•m (the moment is converted, assuming 1Kgf = 10N.)

Test Method and Standardization of TerminologyTest methods and terminology relating to a multilayer piezoelectric actuator have not been standardized yet.Note that characteristic data used in this manual would be changed if they are standardized.Of the terms, the generated force is particularly defined by NEC TOKIN as follows:

Definition of the generated force : Force required to compress the actuator element to its originallength when a load is being imposed on the element after it hasundergone displacement as a result of application of a voltage.

As previously mentioned, the compression force is supplementarily used in this manual, because it isconsidered that the compression resistance represents the phenomenon of the element more faithfully thanthe generated force.

. .


When using our products, the following precautions shouldbe taken.

(1) Safety designing of an apparatus or a system allowing for failures of electronic components usedin the system

In general, failures will occur in electronic components at a certain probability. NEC TOKIN makesevery effort to improve the quality and reliability of electronic component products. However, it isimpossible to completely eliminate the probability of failures. Therefore, when using NEC TOKIN’selectronic component products, systems should be carefully designed to ensure redundancy in theevent of an accident which would result in injury or death, fire, or social damage, to ensure theprevention of the spread of fire, and the prevention of faulty operation. (Please refer to pre-cautions to be taken when using multilayer piezoelectric actuators for the details of failures.)

(2) Quality level of various kinds of parts, and equipment in which the parts can be utilizedElectronic components have a standard quality level unless otherwise specified.

NEC TOKIN classifies the level of quality of electronic component products into three levels, inorder from a lower level, a standard quality level, a special quality level, and a custom quality levelin which a customer individually specifies a quality assurance program. Each of the quality levelshas recommended applications.If a user wants to use the electronic parts having a standard quality level in applications other thanthe applications specified for the standard quality level, they should always consult a member ofour company’s sales staff before using the electronic parts.

Standard quality level : Computers, office automation equipment, communications equipment,measuring instruments, AV equipment, household electrical appli-ances, machine tools, personal equipment, industrial robots

Special quality level : Transportation equipment (automobiles, railways, shipping, or thelike), traffic signals, disaster prevention/crime prevention systems, avariety of safety devices, and medical equipment which is not directlyintended for life-support purposes

Custom quality level : Equipment for airplanes, aerospace equipment, nuclear power controlsystems, and medical equipment, apparatus or system for life-supportpurposes

Unless otherwise shown, the quality level of NEC TOKIN’s electronic component products includedin documents such as catalogues, data sheets or data books is the standard quality level.

(3) This manual is subject to change without notice.

The contents of this manual are based on data which is correct as of March 2002, and they maybe changed without notice. If our products are used for mass-production design, please cousultwith a member of our company’s sales staff by way of precaution.

(4) Reprinting and copying of this manual without prior written permission from NEC TOKIN Corpo-ration are not permitted.

(5) Industrial property problems

In the event any problems associated with industrial property of a third party arising as a result ofthe use of our products, NEC TOKIN assumes no responsibility for problems other than problemsdirectly associated with the constitution and manufacturing method of the products.

(6) Should any of these products come under the category of strategic goods or services (accordingto Japan's foreign trade and foreign exchange regulations), the sender must obtain an exportlicense from the Japanese Government before said products can be exported outside Japan.

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PRECAUTIONS TO BE TAKEN WHEN USING MULTILAYERjmaps/research/datasheets/... · 2. The main failures with multilayer piezoelectric actuators are deterioration of insulation resistance,