Reflective liquid crystal display device

Claim 2

A reflective liquid crystal display device comprising: a reflector; a liquid crystal cell formed by laminating upper and lower orientation layers, upper and lower electrodes, upper and lower substrates, and upper and lower polarizers arranged in order above and below a liquid crystal layer, respectively; said liquid crystal cell is provided with a viewing angle dependence so that a transmission ratio of a dark display section to a bright display section for light incident upon said liquid crystal cell is less than 2 at a viewing angle range which includes a direction which is normal to a plane of a surface of said reflector; wherein the direction of the viewing angle range is aligned with the normal with respect to said liquid crystal cell; wherein a dark display shadow is substantially extinguished; and wherein the surface tilt angle of said reflector with respect to the plane of extension of said reflector is within a range of 10° to 35°.

Claim 3

A reflective liquid crystal display device according to claim 1, wherein said upper and lower substrates are first and second transparent substrates sandwiching said liquid crystal layer, said first substrate being disposed on a front surface side and said second substrate being disposed on a rear surface side of the liquid crystal layer; wherein a phase plate is disposed on the outer surface of said first transparent substrate; said upper polarizer being a first polarizer disposed on the outer surface of said phase plate; said lower polarizer being a second polarizer disposed on the outer side of said second transparent substrate; and said reflector being a directional reflector disposed on the outer side of said second polarizer; and wherein when refractive indices of said phase plate in the directions of two electro-optical principal axes which perpendicularly cross in a plane of said phase plate are set to n x and n y (n x >n y ) and a refractive index in the direction of the thickness of said phase plate is set to n z , refractive index characteristics of said phase plate satisfy the following expression: 0.3≧(n.sub.Z -n.sub.X)/(n.sub.y -n.sub.X); when a retardation of said phase plate lies within a range from 320 nm to 420 nm, and the direction which halves the direction of an orientating process of said upper and lower orientation layers which are first and second orientation layers disposed on the facing surfaces of said first and second transparent substrates, is set to an azimuth of 0° and the azimuth is defined counterclockwise when viewed from outside of said first transparent substrate, an azimuth of an absorption axis of said second polarizer lies within a range from 140° to 185°; an azimuth of a slow axis of said phase plate lies within a range from 45° to 80°; and an azimuth of an absorption axis of said first polarizer lies within a range from -10° to 35°.

Claim 4

A reflective liquid crystal display device according to claim 1, wherein said upper and lower substrates are first and second transparent substrates sandwiching said liquid crystal layer, said first substrate being disposed on a front surface side and said second substrate being disposed on a rear surface side of said liquid crystal layer; wherein a phase plate is disposed on the outer surface of said first transparent substrate; said first polarizer being a first polarizer disposed on the outer surface of said phase plate; said lower polarizer being a second polarizer disposed on the outer side of said second transparent substrate; and said reflector being a directional reflector disposed on the outer side of said second polarizer; and wherein when refractive indices of said phase plate in the directions of two electro-optical principal axes which perpendicularly cross in a plane of said phase plate are set to n x and n y (n x >n y ) and a refractive index in the direction of the thickness of said phase plate is set to n z , refractive index characteristics of said phase plate satisfy the following expression: 0.3≧(n.sub.Z -n.sub.X)/(n.sub.y -n.sub.X); when a retardation of said phase plate lies within a range from 540 nm to 680 nm, and the direction which halves the direction of an orientating process of said upper and lower orientation layers which are first and second orientation layers disposed on the facing surfaces of said first and second transparent substrates, is set to an azimuth of 0° and the azimuth is defined counterclockwise when viewed from outside of said first transparent substrate, an azimuth of an absorption axis of said second polarizer lies within a range from 140° to 185°; an azimuth of a slow axis of said phase plate lies within a range from 45° to 80°; and an azimuth of an absorption axis of said first polarizer lies within a range from 90° to 35°.

Claim 5

A reflective liquid crystal display device comprising: a reflector; a liquid crystal cell formed by laminating upper and lower orientation layers, upper and lower electrodes, upper and lower substrates, and upper and lower polarizers arranged in order above and below a liquid crystal layer, respectively; said liquid crystal cell is provided with a viewing angle dependence so that a transmission ratio of a dark display section to a bright display section for light incident upon said liquid crystal cell is less than 2 at a viewing angle range which includes a direction which is normal to a plane of a surface of said reflector; wherein the direction of the viewing angle range is aligned with the normal with respect to said liquid crystal cell; wherein a dark display shadow is substantially extinguished; wherein the surface tilt angle of said reflector with respect to the plane of extension of said reflector is within a range of 10° to 35°, wherein a polarization change Δ defined by the following formula is at a minimum value in the direction of a user's azimuth angle of 90° and is at a value greater than 0.5 at a direction normal to a plane of the display device Δ=C(1-S.sub.1B S.sub.1D -S.sub.2B S.sub.2D -S.sub.3B S.sub.3D), wherein C is a predetermined value, S 1B , S 2B and S 3B are stokes parameters for indicating the polarization light condition of a transmission polarization light at the bright display section, and S 1D , S 2D , and S 3D are stokes parameters for indicating a polarization light condition of a transmission polarization light at the dark display section.

Claim 6

A reflective liquid crystal display device comprising: a reflector; a liquid crystal cell formed by laminating upper and lower orientation layers, upper and lower electrodes, upper and lower substrates, and upper and lower polarizers arranged in order above and below a liquid crystal layer, respectively; said liquid crystal cell is provided with a viewing angle dependence so that a transmission ratio of a dark display section to a bright display section for light incident upon said liquid crystal cell is less than 2 at a viewing angle range which includes a direction which is normal to a plane of a surface of said reflector; wherein the direction of the viewing angle range is aligned with the normal with respect to said liquid crystal cell; wherein a dark display shadow is substantially extinguished; wherein the surface tilt angle of said reflector with respect to the plane of extension of said reflector is within a range of 10° to 35°, wherein a polarization change Δ defined by the following formula is at a minimum value in the direction of a user's azimuth angle of 90° and is at a value greater than 0.5 at a direction normal to a plane of the display device Δ=C(1-S.sub.1B S.sub.1D -S.sub.2B S.sub.2D -S.sub.3B S.sub.3D), wherein C is a predetermined value, S 1B , S 2B and S 3B are stokes parameters for indicating the polarization light condition of a transmission polarization light at the bright display section, and S 1D , S 2D , and S 3D are stokes parameters for indicating a polarization light condition of a transmission polarization light at the dark display section.

Claim 7

A reflective liquid crystal display device according to claim 4, wherein said upper and lower substrates are first and second transparent substrates sandwiching said liquid crystal layer, said first substrate being disposed on a front surface side and said second substrate being disposed on a rear surface side of the liquid crystal layer; wherein a phase plate is disposed on the outer surface of said first transparent substrate; said upper polarizer being a first polarizer disposed on the outer surface of said phase plate; said lower polarizer being a second polarizer disposed on the outer side of said second transparent substrate; and said reflector being a directional reflector disposed on the outer side of said second polarizer; and wherein when refractive indices of said phase plate in the directions of two electro-optical principal axes which perpendicularly cross in a plane of said phase plate are set to n x and n y (n x >n y ) and a refractive index in the direction of the thickness of said phase plate is set to n Z , refractive index characteristics of said phase plate satisfy the following expression: 0.3≧(n.sub.Z -n.sub.X)/(n.sub.y -n.sub.x); when a retardation of said phase plate lies within a range from 320 nm to 420 nm, and the direction which halves the direction of an orientating process of said upper and lower orientation layers which are first and second orientation layers disposed on the facing surfaces of said first and second transparent substrates, is set to an azimuth of 0° and the azimuth is defined counterclockwise when viewed from outside of said first transparent substrate, an azimuth of an absorption axis of said second polarizer lies within a range from 140° to 185°; an azimuth of a slow axis of said phase plate lies within a range from 45° to 80°; and an azimuth of an absorption axis of said first polarizer lies within a range from -10° to 35°.

Claim 8

A reflective liquid crystal display device according to claim 4, wherein said upper and lower substrates are first and second transparent substrates sandwiching said liquid crystal layer, said first substrate being disposed on a front surface side and said second substrate being disposed on a rear surface side of said liquid crystal layer; wherein a phase plate is disposed on the outer surface of said first transparent substrate; said first polarizer being a first polarizer disposed on the outer surface of said phase plate; said lower polarizer being a second polarizer disposed on the outer side of said second transparent substrate; and said reflector being a directional reflector disposed on the outer side of said second polarizer; and wherein when refractive indices of said phase plate in the directions of two electro-optical principal axes which perpendicularly cross in a plane of said phase plate are set to n x and n y (n x >n y ) and a refractive index in the direction of the thickness of said phase plate is set to n z , refractive index characteristics of said phase plate satisfy the following expression: 0.3≧(n.sub.Z -n.sub.X)/(n.sub.y -n.sub.x); when a retardation of said phase plate lies within a range from 540 nm to 680 nm, and the direction which halves the direction of an orientating process of said upper and lower orientation layers which are first and second orientation layers disposed on the facing surfaces of said first and second transparent substrates, is set to an azimuth of 0° and the azimuth is defined counterclockwise when viewed from outside of said first transparent substrate, an azimuth of an absorption axis of said second polarizer lies within a range from 140° to 185°; an azimuth of a slow axis of said phase plate lies within a range from 45° to 80°; and an azimuth of an absorption axis of said first polarizer lies within a range from 90° to 35°.