Bring polarizing film

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Bring polarizing film

Palffy – Muhorray, “The Diverse World of Liquid Crystals”, Physics Today, Sept. 2007

Some slides need re-organizing and tighter message.

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LC = a misnomer.

These systems are not crystals….and the study is not necessarily confined to liquids either.

First related observations: Myelin 1700s –1850

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Discovery due to Reinitzer & Lehman = Botanist & Physicist

Irridescent beetle colors may Trace to “liquid” “crystal”behavior. (from a beetle wiki)See also Srinivasarao Science 2009

Discovery is usually associated with the behavior of cholesteryl benzoate, which by ~1888 was known to have two melting points.

Note the rather extended shape!

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1949 Onsager f > 4/x (x = L/d) kind of a pure packing argument, logs in a river photo.

1959 Maier Saupe extend to temperature; anisotropic polarizability below some crit temperature

1965 Kent State Glenn Brown

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classifications

Nematic smectic (a,c), chiral

Thermotropic, lyotropic

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The "Great Raft," a huge mass of timber that formed a logjam, dammed up the Red River and flooded the surrounding area. Photo by R. B. Taylor, courtesy Louisiana State University, Shreveport, Noel Memorial Library Archives.

http://www.texasbeyondhistory.net/timberhill/images/greatraft.html

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http://farm1.static.flickr.com/57/220279395_26a24ae64f.jpg

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Biaxial nematic

http://www.thehockeyshop.com/hockey-sticks.htm

http://the2manadvantage.blogspot.com/2007/10/nhl-is-opening-flagship-store-in-nyc.html

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LC’s as displays. Why do we need something besides the CRT?

Vacuum! How heavy does a CRT have to be to be strong enough to maintain vacuum, since the e-beam has to travel from gun to phosphor screen? This is a fundamental limitation.

By contrast, the limiting size of LCD’s = production yields of large, defect-free films. There is no fundamental limitation, merely a matter of engineering.

The problem is CRTs have a heart of glass!

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Casio Hybrid ProjectorActually, this isn’t an LCD display.Doesn’t use a lamp either….$800 gets you a “hybrid” light source with DLP technology. Animated GIF of how it works.

LG HS201 SlimSort of 6” x 6” sizeNot an LCDNo lamp$550

Even so, very huge LCD displays are not with us yet; we use projection. For now.

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DIY LCD Projector Videos

http://www.youtube.com/watch?v=FKrKHtdXroo

http://www.youtube.com/watch#!v=KZ_KpQV1Vmo&feature=related

Heart of Glass doesn’t cut it in the plastics world:

Cracker box:

http://www.youtube.com/watch?v=NWlsPfPZTdc OHP

http://www.youtube.com/watch?v=n6n6jW0XIV0&feature=related DIY LCD Projector >500000 views

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The idea of using LCs for light display goes back to simple rubbing of glass experiments. 1911 It is found that rubbing glass can align the LC molecules; crossed

rubbing leads to no transmission of light through the objects.

1922 word mesomorphic coined

1935 Freedericksz finds E field can align LCs

1936 patent (British) to Marconi for “light valves….for use in television, facsimile telegraph and other systems”

Postwar: synthesis of mesogens

By 1950s, a thriving subject

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Twisted nematic LC (Saupe 1969, KSU)

How to twist it? How to switch it?

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From PC World ~2000 (I think)

18http://www.maxi-pedia.com/tft+lcd+display+monitor+panel

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The invention of the TFT made this practical in large arrays.

http://en.wikipedia.org/wiki/TFT_LCD

The TFT was invented in 1973 by Westinghouse (120 x 120 pixels in 6” x 6” array = 0.05”/pixel).

By this time, the USA had already ceded other videotechnology, such as video tape recording, to theJapanese.

TFT/LCD panels met the same fate.

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About 40% of Corning’s $4.6B revenues in 2006 came from LCD glass.

So…how do you make a perfectly flat, bubble-free piece of glass?

Plastics’ role: under 30” the sandwich can be made from plastic.

From some website: The liquid crystal is placed between the two sheets in a patterned plastic sheet that divides the liquid into individual shutters and keeps the sheets at a precise distance from each other.

There are opportunities for polymers in this game.

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Plasma….its days probably also numbered. Probably better quality than LCD, though.

Plasma http://electronics.howstuffworks.com/plasma-display2.htm

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Research continues. This Fabry-Perot interferometer device requires poly(ethylene napthalate) which deflects to create a light gate at a particular color.

http://spie.org/x8775.xml?ArticleID=x8775

This color display isflexible!

Harry Potter-Style Newspapers a Reality http://www.dailymail.co.uk/news/worldnews/article-1207944/Harry-Potter-meets-Minority-Report-video-adverts-magazines-reality.html

PEN, even better barrier properties than PET

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The future is probably with these technologies: OLED FED SED

The LCD is limited by energy cost—tosses away an awful lot of light; 40” display about 250 W, same as CRT.

Organic LEDs will light up just where/when you need.

FED/SED display = array of nanotubes that makes electrons for phosphors just where/when you need them.

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Even others can be considered.

Electronic paper Wiki

Palfy-Muhorray review article

50 mm