Patent ID: 7327420

Claim:
A reflective liquid crystal projection display device comprising: a transparent first substrate with a first alignment film and a first alignment direction; a second substrate with a second alignment film and a second alignment direction; a liquid crystal layer with positive dielectric constant sandwiched between the first substrate and the second substrate, the liquid crystal layer having a phase retardation value dΔn/λ in the range of approximately 0.4 to approximately 0.8, where d is the thickness of the liquid crystal layer; Δn is the birefringence of liquid crystal materials and λ is the wavelength of incident light; and a linear polarizer placed outside of the first substrate which is opposite to the liquid crystal layer to linearly polarize an unpolarized light passing through the linear polarizer, the linear polarizer having a first linear polarization direction; a reflector on an inner side of the second substrate adjacent to the liquid crystal layer to reflect the linearly polarized light, an analyzer having a second linear polarization direction coupled with the linear polarizer on the outside surface of the first substrate for blocking the reflected linearly polarized light to obtain a dark state, the first linear polarization direction of the linear polarizer is approximately perpendicular to the second linear polarization direction of the analyzer, wherein the liquid crystal layer forms a twist angle φ in the range of approximately 40° to approximately 80° between the second alignment direction on the second substrate and the first alignment direction on the first substrate and the first linear polarization direction of the linear polarizer deviates from the bisector direction of the twist angle of the liquid crystal layer, the liquid crystal layer forming a left-handed twist angle φ and the polarization direction of the linear polarizer forms an angle β with the first alignment polarization of the first substrate, wherein the angle β is larger than φ/2 and less than φ/2+15 degrees.