Liquid crystal display device with liquid crystal dispersed or impregnated in a perfluoro-type polymer of perfluoroalkyl acrylate or methacrylate

#The present invention relates to a liquid crystal display device.

#Conventionally, liquid crystal display devices of the twisted nematic (TN) type and the supertwisted nematic (STN) type have been practically used as display devices utilizing electrooptic effects. As well, display devices using ferro-electric liquid crystals has also been proposed. The liquid crystal display devices as noted above need a polarizer as well as an orientation treatment.

#On the other hand, there have been proposed liquid crystal display devices which do not need a polarizer and which utilize liquid crystal scattering effects such as dynamic scattering (DS) effect and phase change (PC) effect. For instance, there has recently been proposed a display device in which liquid crystal molecules are dispersed in a polymer material to obtain the liquid crystal scattering effects. Such a device does not need a polarizer nor orientation treatment.

#FIGS. 1(a) and 1(b) are views for schematically illustrating a matrix-type liquid crystal display device fabricated in the embodiment of the invention;

#FIG. 2 is a view for schematically illustrating a projection apparatus using the matrix-type liquid crystal display device shown in FIGS. 1(a) and 1(b);

#FIG. 3 is a view for schematically illustrating a system for measuring a voltage holding ratio of liquid crystal;

#In the present invention, the liquid crystal layer has a predetermined amount of the liquid crystal material of positive dielectric anisotropy dispersed in the transparent fluoro-type polymer or copolymer.

#The above fluoro-type polymer or copolymer is preferably hard to polarize and to generate ions while being chemically inert and superior in dielectric properties. The fluoro-type polymers include those derived from fluoroalkyl acrylates of methacrylates, in which the alkyl moiety has 1-16 carbon atoms, preferably 2-12 carbon atoms and is preferably per-fluorated. The fluoro-type copolymers include those derived from the above fluoroalkyl acrylate or methacrylate with alkyl acrylate or methacrylate whose alkyl moiety has 1-16 carbon atoms preferably 2-8 carbon atoms. Specific example of the fluoro-type polymers or copolymers include polyperfluorooctyl methacrylate, poly-.beta.-(perfluorooctyl)ethyl acrylate, polytrifluoroethyl acrylate, poly-2,2,3,3-tetrafluoropropyl acrylate, polyper-fluorooctyl acrylate, perfluoroethyl acrylate.2-ethyl-hexyl acrylate copolymer, 2,2,3,3-tetrafluoropropyl acrylate.2-ethylhexyl acrylate copolymer and perfluorooctyl acrylate.2-ethylhexyl acrylate copolymer, and the like.

#As the above liquid crystal material of positive dielectric anisotropy may be used a known liquid crystal material such as ZLI-3219, ZLI-4718, SLI-4749, ZLI-2792, ZLI-4801-000 and ZLI-4801-001 (products of MERCK and CO., Inc.), E7 or E8 (product of BDH CO.), GR-63 (product of CHISSO CORPORATION) or the like. Such a liquid crystal material is used in an amount of 100-1900 weight parts relative to 100 weight parts of the transparent fluoro-type polymer, preferably 150-900 weight parts relative thereto.