Liquid crystal display device with compensation layers

A liquid crystal display device comprising:

• first and second substrates spaced a predetermined distance from each other and having electrodes formed thereon;
• a nematic liquid crystal layer having an optically active material added thereto, said nematic liquid crystal layer having a positive dielectric anisotropy, said nematic liquid crystal layer being sandwiched between the first and second substrates such that the liquid crystal molecules thereof exhibit a helical structure in which they are twisted a predetermined twist angle in a direction across the thickness of the liquid crystal layer, said liquid crystal layer exhibiting an anisotropic differential index of refraction .DELTA.n and a layer thickness d, the value of .DELTA.n.multidot.d being 0.65 .mu.m;
• a light detecting element positioned on one side of the first substrate remote from the liquid crystal layer;
• a polarizing element positioned on one side of the second substrate remote from the liquid crystal layer;
• and
• a film-like sheet having a birefringence and disposed between the light detecting element and the second substrate, said film-like sheet exhibiting an anisotropic differential index of refraction .DELTA.n' and a layer thickness d', the value of .DELTA.n'.multidot.d' being 0.24 .mu.m.

A liquid crystal display device comprising:

• first and second substrates spaced a predetermined distance from each other and having electrodes formed thereon;
• a nematic liquid crystal layer having an optically active material added thereto, said nematic liquid crystal layer having a positive dielectric anisotropy, said nematic liquid crystal layer being sandwiched between the first and second substrates such that the liquid crystal molecules thereof exhibit a helical structure in which they are twisted a predetermined twist angle in a direction across the thickness of the liquid crystal layer, said liquid crystal layer exhibiting an anisotropic differential index of refraction .DELTA.n and a layer thickness d, the value of .DELTA.n.multidot.d being 0.65 .mu.m;
• a light detecting element positioned on one side of the first substrate remote from the liquid crystal layer;
• a polarizing element positioned on one side of the second substrate remote from the liquid crystal layer;
• and
• a first film-like sheet having a birefringence and disposed between the light detecting element and the first substrate, said first film-like sheet exhibiting an anisotropic differential index of refractive .DELTA.n' and a layer thickness d', the value of .DELTA.n'.multidot.d' being within the range of 0.1 to 0.9 .mu.m;
• a second film-like sheet having a birefringence and disposed between the light detecting element and the second substrate, said second film-like sheet exhibiting an anisotropic differential index of refraction .DELTA.n'and a layer thickness d', the value of .DELTA.n.multidot.d' being 0.24 .mu.m.

A liquid crystal display device comprising:

• first and second substrates spaced a predetermined distance from each other and having electrodes formed thereon;
• a nematic liquid crystal layer having a positive dielectric anisotropy, said nematic liquid crystal layer being sandwiched between the first and second substrates such that the liquid crystal molecules thereof exhibit a helical structure in which they are twisted a predetermined twist angle in a direction across the thickness of the liquid crystal layer, said liquid crystal layer exhibiting an anisotropic differential index of refraction .DELTA.n and a layer thickness d, the value of .DELTA.n.multidot.d being 0.65 .mu.m;
• a light detecting element positioned on one side of the first substrate remote from the liquid crystal layer;
• a polarizing element positioned on one side of the second substrate remote from the liquid crystal layer;
• and
• wavelength-dependent contrast variation compensation means for inhibiting the transmission of wavelength-dependent contrast variation, including a film-like sheet having a birefringence and disposed adjacent one of said substrates opposite said nematic liquid crystal layer.