Transflective LCD display device comprising a patterned polarizer, display having the same, and method having the same
View Patent ↗The invention relates to a transflective LCD incorporating a partial mirror ( 224 ) as the transflector. In the transmissive display mode, light from a backlight system ( 240 ) passes apertures ( 226 ) in the transflector ( 224 ). According to the invention, recycling of light to the backlight system ( 240 ) is improved by substantially only polarizing light that passes an aperture. This is achieved by means of a patterned polarizer ( 222 ) extending over the apertures in the partial mirror.
1. A transflective liquid crystal display (LCD) device, comprising:
a liquid crystal display cell including an active layer;
a backlight system to provide backlight to the display cell;
a partial mirror for reflecting ambient light, provided with apertures for passing light originating from the backlight system; and
polarizing means comprising a patterned polarizer between the active layer and the backlight system, said patterned polarizer extending substantially over an area of said apertures in said partial mirror, the patterned polarizer being patterned to expose a portion of the partial mirror.
2. The transflective LCD device of claim 1 , wherein the patterned polarizer is essentially confined within the area of the apertures of the partial mirror.
3. The transflective LCD device of claim 1 , wherein the patterned polarizer comprises a polarizing foil and a further partial mirror having its apertures aligned with the apertures in the partial mirror, the polarizing foil being essentially sandwiched between the two partial mirrors.
4. The transflective LCD device of claim 1 , wherein the patterned polarizer is a linear polarizer.
5. The transflective LCD device of claim 3 , wherein the polarizing means further includes a quarterwave retarder between the active layer and the backlight system.
6. The transflective LCD device of claim 1 , wherein the partial mirror is arranged for recycling light to the backlight system.
7. The transflective LCD device of claim 1 , wherein the polarizing means includes a reflective polarizer.
8. The transflective LCD device of claim 2 in which the polarizing means comprises an absorbing patterned polarizer and a reflective patterned polarizer.
9. The transflective LCD device of claim 2 in which the patterned polarizer does not substantially extend outside of the area of the apertures of the partial mirror.
10. The transflective LCD device of claim 2 in which the patterned polarizer is disposed between the partial mirror and the backlight system, and the pattern of the polarizer is configured to polarize a first portion of backlight from the backlight system that passes the apertures in the partial mirror and to allow a second portion of the backlight to be reflected by the partial mirror without being polarized by the polarizer.
11. The transflective LCD device of claim 2 , comprising a quarterwave retarder that is also essentially confined within the area of the apertures of the partial mirror.
12. The transflective LCD device of claim 7 in which the reflective polarizer comprises a wire-grid polarizer.
13. A display comprising:
a liquid crystal layer;
an at least partially reflective layer to reflect ambient light, the at least partially reflective layer disposed between the liquid crystal layer and a backlight module, the partially reflective layer having apertures to pass backlight from the backlight module to the liquid crystal layer; and
a patterned polarizer disposed between the liquid crystal layer and the backlight module, the patterned polarizer extending substantially over an area of the apertures in the partially reflective layer, the patterned polarizer being patterned to expose a portion of the partially reflective layer.
14. The display of claim 13 in which the patterned polarizer is substantially confined within the area of the apertures of the at least partially reflective layer.
15. The display of claim 14 , comprising a quarterwave retarder also substantially confined within the area of the apertures of the at least partially reflective layer.
16. The display of claim 13 in which the patterned polarizer is disposed between the partially reflective layer and the backlight module, and the pattern of the polarizer is configured to polarize a first portion of backlight from the backlight module that passes the apertures in the partially reflective layer and to allow a second portion of the backlight to be reflected by the partially reflective layer without being polarized by the polarizer.
17. The display of claim 13 in which the polarizer comprises a reflective polarizer.
18. A method of operating a liquid crystal display, the method comprising:
providing backlight from a backlight module;
passing a first portion of the backlight through apertures in an at least partially reflective layer positioned between the backlight module and a liquid crystal layer;
passing the first portion of the backlight through a patterned polarizer that extends substantially over the apertures, the patterned polarizer being patterned to expose the partially reflective layer; and
transmitting a second portion of the backlight from the backlight module to the partially reflective layer, and reflecting the second portion of the backlight by using the exposed portion of the partially reflective layer without passing the second portion of the backlight through the patterned polarizer.
19. The method of claim 18 in which the patterned polarizer has an area that is substantially equal to an area of the apertures of the partially reflective layer.
20. The method of claim 18 in which the patterned polarizer is disposed between the partially reflective layer and the backlight module, the patterned polarizer having openings that expose the partially reflective layer to allow the second portion of the backlight to be reflected by the partially reflective layer without being polarized by the polarizer.