Optically compensating film, optical compensator and liquid crys

Optical: systems and elements – Holographic system or element – Using a hologram as an optical element

Patent

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

359 63, G02F 11335

Patent

active

053963555

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

The present invention relates to a optically compensating film and an optical compensator which are capable of providing a liquid crystal display with improved display coloration and contrast ratio.


BACKGROUND ART

As a liquid crystal display device utilizing a supertwisted nematic structure, an STN liquid crystal display of the construction: first polarizer/driver liquid crystal cell/hue compensating liquid crystal cell/second polarizer has been developed [Nikkei Microdevices, August 1987, pp. 36-38 and Nikkei Micro-devices, October 1987, pp. 84-88].
The light incident on and passing through the first polarizer becomes linearly polarized light which, in turn, is converted to elliptically polarized light by birefringence as it passes through the driver liquid crystal cell. The elliptic polarization rate and orientational angle involved are dependent on the wavelength. However, the light emerging from the driver liquid crystal cell is twisted in the reverse direction as it passes through the hue compensating liquid crystal cell, so that the elliptically polarized light is reconverted to linearly polarized light (that is to say the phase difference is cancelled), which is taken out through the second polarizer. In this way, the wavelength dependence of transmitted light is eliminated and a substantially white-and-black display is obtained. Therefore, if necessary, a full-color display can be implemented by adding color filters.
The above STN liquid crystal display incorporating a driver liquid crystal cell and a hue compensating liquid crystal cell is thick and heavy and, as an additional disadvantage, costly to manufacture. There also is the problem that the display is too dark in the reflecting mode.
Therefore, to overcome these disadvantages, a system (hereinafter referred to as Formulated Super Twisted Nematic (FTN) mode) incorporating an optical compensator comprising a monoaxially oriented polymer film laminated with an optically isotropic film on either side thereof in lieu of said hue compensating liquid crystal cell is attracting attention. The basic architecture of this FTN liquid crystal display is: polarizer/liquid crystal cell/optical compensator/polarizer.
Japanese Patent Application Kokai No. 64-519, as filed earlier by one of the inventors of the present invention, discloses that, as the monoaxially oriented film mentioned above, polyvinyl alcohol, polyester, polyetheranide, polyethylene, etc. can be employed.
Japanese Patent Application Kokai No. 1-118805 describes an optical compensator obtainable by orienting a film of polyvinyl alcohol or a derivative thereof in one direction, treating the oriented film with an aqueous boric acid-containing solution and laminating an optically non-oriented polymer film on one or either side of said oriented film. The derivative of polyvinyl alcohol mentioned above means a polyvinylacetal such as polyvinylbutyral, polyvinylformal, etc.
Japanese Patent Application Kokai No. 1-118819 and Japanese Patent Application Kokai No. 1-124821 disclose the use of an optically compensating film comprising an oriented synthetic resin film or an optical compensator comprising said optically compensating film and an optically isotropic amorphous film laminated at least on one side thereof as one of the transparent electrode supporting substrates of a liquid crystal cell. Japanese Patent Application Kokai No. 1-127329 discloses a laminate having an optical compensating function which is obtainable by laminating an optical compensator similar to the above with a release sheet through an adhesive layer. It is disclosed in these patent literature that polycarbonate, phenoxy resin, polyparabanic acid resin, fumaric acid resin, polyamino acid resin, polystyrene, polysulfone, polyether polysulfone, polyarylene ester, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinyl chloride, polymethyl methacrylate, polyester, cellulosic polymer, etc. can be employed. Incidentally, it is to be noted that these patent applications as well as Japanese Patent Applic

REFERENCES:
patent: 5061042 (1991-10-01), Nakamura et al.
patent: 5142393 (1992-08-01), Okumura et al.

LandOfFree

Say what you really think

Search LandOfFree.com for the USA inventors and patents. Rate them and share your experience with other people.

Rating

Optically compensating film, optical compensator and liquid crys does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Optically compensating film, optical compensator and liquid crys, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optically compensating film, optical compensator and liquid crys will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-1410701

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.