LCD with complimentary heterogeneous polarizers for polarization light recycling

• US 7,286,196 B1
• Filed: 12/29/2006
• Issued: 10/23/2007
• Est. Priority Date: 12/29/2006
• Status: Active Grant

• Current Assignee: Viterra Incorporated (Glencore Plc)
• Original Assignee: Viterra Incorporated (Glencore Plc)
• Inventors: Bhalla, Jagmohan
• Primary Examiner(s): Nelms; David
• Assistant Examiner(s): Kim; Richard H
• Application Number:
  US11/618,254
• Time in Patent Office: 298 Days
• Field of Search: 349/96
• US Class Current: 349/96
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133538 with spatial distribution of the polarisation direction
• CPC Class Codes: G02F 1/133757 with different alignment orientations

Abstract

An electro-optical display system includes a rear reflective heterogeneous polarizer having first and second regions. The first region transmits a first polarization state and reflects a second polarization state and the second region transmits the second polarization state and reflects the first polarization state. The system further includes a front heterogeneous polarizer having third and fourth regions. The third region is substantially aligned with and approximately the same size and shape as the first region and the fourth region is substantially aligned with and approximately the same size and shape as the second region.

Claims

1. An electro-optical display system comprising:

a rear reflective heterogeneous polarizer having a first and a second region, wherein said first region transmits a first polarization state and reflects a second polarization state and said second region transmits the second polarization state and reflects the first polarization state;

a front heterogeneous polarizer having a third and a fourth region, wherein said third region is substantially aligned with and approximately the same size and shape as said first region and said fourth region is substantially aligned with and approximately the same size and shape as said second region; and

a light modulation unit coupled to said front and rear polarizers, wherein said modulation unit modifies the polarization state of transmitted light, wherein said light modulation unit is a liquid crystal display layer;

said layer having fifth and sixth regions that are oriented relative to the first and second regions of said rear polarizer and the third and fourth regions of said front polarizer;

wherein said fifth region is substantially aligned with and approximately the same shape and size as said first region and said third region and wherein said sixth region is substantially aligned with and approximately the same shape and size as said second region and said fourth region.

2. The display system of claim 1, wherein said third region transmits the second polarization state and said fourth region transmits the first polarization state.

3. The display system of claim 2, wherein said third region reflects the first polarization state and said fourth region reflects the second polarization state.

4. The display system of claim 1, wherein said third region transmits the first polarization state and said fourth region transmits the second polarization state.

5. The display system of claim 1, further comprising a rear reflector.

6. The display system of claim 1, further comprising a backlight unit.

7. A method of operating an electro-optical display system comprising:

generating unpolarized light;

transmitting the unpolarized light to a rear reflective heterogeneous polarizer having a first and a second region, wherein said first region transmits a first polarizer state and reflects a second polarization state and said second region transmits the second polarization state and reflects the first polarization state;

modifying the polarization of rear polarizer light by a liquid crystal layer, wherein said rear polarizer light is transmitted from said rear polarizer; and

transmitting the modified light to a front heterogeneous polarizer having a third and a fourth region, wherein said third region is substantially aligned with and approximately the same size and shape as said first region and said fourth region is substantially aligned with and approximately the same size and shape as said second region, wherein said liquid crystal layer has a fifth and a sixth region that are oriented relative to the first and second regions of said rear polarizer and the third and fourth regions of said front polarizer;

wherein said fifth region is substantially aligned with and approximately the same shape and size as the first region and the third region, and wherein the sixth region is substantially aligned with and approximately the same shape and size as the second region and the fourth region.

8. The method of claim 7, further comprising:

recycling light reflected by the rear heterogeneous polarizer regions with a reflector and redirecting the reflected light back towards the liquid crystal layer.

9. The method of claim 7, wherein said third region transmits the second polarization state and said fourth region transmits the first polarization state.

10. The method of claim 9, wherein said third region reflects the first polarization state and said fourth region reflects the second polarization state.

11. The method of claim 7 wherein said third region transmits the first polarization state and said fourth region transmits the second polarization state.

12. An electro-optical display system comprising:

a rear reflective heterogeneous polarizer having a first and a second region;

a front heterogeneous polarizer having a third and a fourth region, and a light modulation unit sandwiched between said front and rear polarizers, wherein said first region transmits a first polarization state and reflects a second polarization state and said second region transmits the second polarization state and reflects the first polarization state; and

wherein said third region is substantially aligned with and approximately the same size and shape as said first region and said fourth region is substantially aligned with and approximately the same size and shape as said second region, wherein said light modulation unit is a liquid crystal display layer;

said layer having a fifth and a sixth region that are oriented relative to the first and second regions of said rear polarizer and the third and fourth regions of said front polarizer;

wherein said fifth region is substantially aligned with and approximately the same shape and size as the first region and the third region, and wherein the sixth region is substantially aligned with and approximately the same shape and size as the second region and the fourth region.

13. The system of claim 12, further comprising a rear reflector.

14. The system of claim 12, further comprising a backlight unit.