Liquid crystal cell using the electrically controlled birefringence effect and a uniaxial medium of negative optical anisotropy usable therein

  • US 4,889,412 A
  • Filed: 02/17/1987
  • Issued: 12/26/1989
  • Est. Priority Date: 02/28/1986
  • Status: Expired due to Term
First Claim
Patent Images

1. A liquid crystal cell assembly using the electrically controlled birefringence effect and having spaced apart sides, one of which is exposed to an incident light, said assembly comprising:

  • a nematic liquid crystal molecular layer of positive optical anisotropy;

    at least two electrodes, one on either side of said liquid crystal layer, with the electrode located on said one side exposed to incident light being transparent;

    the molecules of said liquid crystal layer being substantially oriented in a homeotropic direction in the absence of a voltage between said electrodes;

    at least one means for polarizing said incident light located on said one side exposed to said incident light; and

    at least one layer of medium for compensating the birefringence of said nematic liquid crystal layer in its homeotropic structure for improving oblique observation of said cell, said medium having three principal optical indices each corresponding to an axis, one of said indices being weaker than the other two indices, and that axis which corresponds to said weak index being parallel to said homeotropic direction.

View all claims
    ×
    ×

    Thank you for your feedback

    ×
    ×