Back lit cholesteric liquid crystal display

A bistable, backlit cholesteric liquid crystal display, comprising:

• a) a cholesteric liquid crystal material located between first and second substrates, said cholesteric liquid crystal material including a planar texture having a circular polarization of a predetermined handedness and a focal conic texture that are stable in an absence of an electric field, said second substrate being closer to an exterior of the display than said first substrate;
• b) drive electronics adapted to electrically address regions of the cholesteric liquid crystal material effective to cause said cholesteric liquid crystal material to exhibit the focal conic and planar textures resulting in an image;
• c) a first quarter wave retarder;
• d) a second quarter wave retarder;
• e) a linear polarizer located between said first quarter waver retarder and said second quarter wave retarder;
• f) a transflector having a light reflective side and a light transmitting side, the light reflective side being adapted to reflect light received from said second quarter wave retarder, wherein said first quarter wave retarder, said linear polarizer and said second quarter wave retarder are located between said transflector and said first substrate;
• and
• g) a light source adapted to be selectively energizable to emit light, said light passing through said transflector from said light transmitting side toward said light reflecting side.

A bistable, backlit cholesteric liquid crystal display, comprising:

• a) a cholesteric liquid crystal material located between first and second substrates, said cholesteric liquid crystal material including focal conic and reflective planar textures that are stable in an absence of an electric field, an alignment material on at least one of said first and second substrates, said alignment material being adapted to orient molecules of said cholesteric liquid crystal material effective to enable light reflected from said display to have an S3 stokes parameter greater than 0.75, said second substrate being closer to an exterior of the display than said first substrate;
• b) drive electronics adapted to electrically address regions of the cholesteric liquid crystal material effective to cause said cholesteric liquid crystal material to exhibit the focal conic and planar textures resulting in an image;
• c) a bi-directional circular polarizer having opposing sides, wherein said bi-directional circular polarizer is adapted to circularly polarize light incident from either of said opposing sides including passing circularly polarized light to said layer of cholesteric liquid crystal material;
• d) a transflector having a light reflective side and a light transmitting side, the light reflective side being adapted to reflect light received from said bi-directional circular polarizer, said bi-directional circular polarizer being located between said transflector and said first substrate;
• and
• e) a light source adapted to be selectively energizable to emit light, said light passing through said transflector from said light transmitting side toward said light reflecting side.

A bistable, backlit cholesteric liquid crystal display device, comprising:

• a layer of cholesteric liquid crystal material including focal conic and reflective planar textures that are stable in an absence of an electric field, said layer having a first side and a second side, the second side being closer to an exterior of the display device than said first side;
• means for selectively addressing regions of the cholesteric liquid crystal material effective to cause said cholesteric liquid crystal material to exhibit the focal conic and reflective planar textures resulting in an image;
• a bi-directional circular polarizer comprising a first quarter wave retarder, a second quarter wave retarder and a linear polarizer located between said first quarter wave retarder and said second quarter wave retarder;
• a transflector having a light reflective side and a light transmitting side, said bi-directional circular polarizer being located between said transflector and said first side of said cholesteric liquid crystal material, the light reflective side being adapted to reflect light received from said bi-directional circular polarizer;
• and
• a light source adapted to be selectively energizeable to emit light, said light passing through said transflector from said light transmitting side toward said light reflecting side.

A bistable, backlit cholesteric liquid crystal display comprising:

• a layer of cholesteric liquid crystal material including focal conic and reflective planar textures that are stable in an absence of an electric field, said layer having a first side and a second side, the second side being closer to an exterior of the display than the first side;
• drive electronics adapted to electrically address regions of the cholesteric liquid crystal material effective to cause said cholesteric liquid crystal material to exhibit the focal conic and planar textures resulting in an image;
• polarizing means for circularly polarizing light in two opposite directions and for passing circularly polarized light to said layer of cholesteric liquid crystal material;
• a transflector having a light reflective side and a light transmitting side, said bi-directional circular polarizer being located between said transflector and said first side of said layer of cholesteric liquid crystal material, the light reflective side being adapted to reflect light received from said polarizing means;
• and
• a light source adapted to be selectively energizable to emit light, said light passing through said transflector from said light transmitting side toward said light reflecting side.

A bistable, backlit cholesteric liquid crystal display comprising:

• a layer of cholesteric liquid crystal material including focal conic and reflective planar textures that are stable in an absence of an electric field, said layer having a first side and a second side, the second side being closer to an exterior of the display than the first side, an alignment material on at least one of said first and second substrates, said alignment material being adapted to orient molecules of said cholesteric liquid crystal material effective to enable light reflected from said display to have an S3 stokes parameter greater than 0.75;
• drive electronics adapted to electrically address regions of the cholesteric liquid crystal material effective to cause said cholesteric liquid crystal material to exhibit the focal conic and planar textures resulting in an image;
• a bi-directional circular polarizer;
• a transflector having a light reflective side and a light transmitting side, said bi-directional circular polarizer being located between said transflector and said first side of said layer of cholesteric liquid crystal material, the light reflective side being adapted to reflect light received from said bi-directional circular polarizer;
• and
• a light source selectively energizeable to emit light, said light passing through said transflector from said light transmitting side toward said light reflecting side.

A bistable, backlit cholesteric liquid crystal display comprising:

• a layer of cholesteric liquid crystal material including focal conic and reflective planar textures that are stable in an absence of an electric field, said layer having a first side and a second side, the second side being closer to an exterior of the display than the first side, a substrate having one side in contact with said second side of said layer of cholesteric liquid crystal display material and another side forming an external surface of said display;
• drive electronics adapted to electrically address regions of the cholesteric liquid crystal material effective to cause said cholesteric liquid crystal material to exhibit the focal conic and planar textures resulting in an image;
• a bi-directional circular polarizer;
• a transflector having a light reflective side and a light transmitting side, said bi-directional circular polarizer being located between said transflector and said cholesteric liquid crystal material, the light reflective side being adapted to reflect light received from said bi-directional circular polarizer;
• and
• a light source adapted to be selectively energizable to emit light, said light passing through said transflector from said light transmitting side toward said light reflecting side.

A bistable, backlit cholesteric liquid crystal display comprising:

• a layer of cholesteric liquid crystal material including focal conic and reflective planar textures that are stable in an absence of an electric field, said layer having a first side and a second side, the second side being closer to an exterior of the display than the first side;
• electrical addressing means for electrically addressing regions of the cholesteric liquid crystal material effective to cause said cholesteric liquid crystal material to exhibit the focal conic and planar textures resulting in an image;
• polarizing means for circularly polarizing light in two opposite directions including passing circularly polarized light to said layer of cholesteric liquid crystal material;
• transflector means for reflecting light incident on one side of the transflector and transmitting light incident on the other side of the transflector, said polarizing means being located between said transflector and said first side of said layer of cholesteric liquid crystal material;
• and
• means for emitting light from said light transmitting side of said transflector toward said light reflecting side of said transflector.

A bistable, backlit cholesteric liquid crystal display comprising:

• a layer of cholesteric liquid crystal material including focal conic and reflective planar textures that are stable in an absence of an electric field, said layer having a first side and a second side, the second side being closer to an exterior of the display than the first side;
• drive electronics adapted to electrically address regions of the cholesteric liquid crystal material effective to cause said cholesteric liquid crystal material to exhibit the focal conic and planar textures resulting in an image;
• a bi-directional circular polarizer;
• a transflector having a light reflective side proximal to said bi-directional circular polarizer and a light transmitting side distal from said bi-directional circular polarizer, said bi-directional circular polarizer being located between said transflector and said first side of said layer of chiral nematic liquid crystal material;
• and
• a light source located behind said transflector proximal to said light transmitting side and distal to said light reflecting side.