Transflective layer for displays

• US 6,975,455 B1
• Filed: 04/18/2000
• Issued: 12/13/2005
• Est. Priority Date: 04/18/2000
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Bennet, Robert, Watson, Philip E., Kotchick, Keith M.
• Primary Examiner(s): Shafer, Ricky D.
• Application Number:
  US09/551,111
• Time in Patent Office: 2,065 Days
• Field of Search: 359/487, 359/488, 359/495, 359/497, 359/500, 359/494, 359/502, 359/599, 349/96, 349/97, 349/98
• US Class Current: 359/485.03
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G02B 5/305 including organic materials, e.g. polymeric layers
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one

Abstract

A transflective assembly includes an absorbing polarizer and a first reflective polarizer disposed to reflect at least a portion of light transmitted through the absorbing polarizer. A second reflective polarizer is disposed between the absorbing polarizer and the first reflective polarizer. The second reflective polarizer reflects light transmitted through the first reflective polarizer having a polarization absorbable in the absorbing polarizer, and transmits light transmitted through the absorbing polarizer towards the first reflective polarizer.

Claims

1. A passive transflective assembly for use in a display between a display module and a light source, the assembly comprising:

an absorbing polarizer on a display side of the assembly, defining an absorbing polarizer transmission polarization state;

a first reflective polarizer disposed to receive light transmitted through the absorbing polarizer from the display side of the assembly, the first reflective polarizer defining a first reflective polarizer transmission polarization state in a preselected relationship with the absorbing polarizer transmission polarization state; and

a second reflective polarizer layer disposed on a light source side of the assembly to receive light transmitted through the first reflective polarizing layer from the absorbing polarizer, the second reflective polarizer defining a second reflective polarizer transmission polarization state different from the absorbing polarizer transmission polarization state.

2. An assembly as recited in claim 1, wherein the first reflective polarizer transmission polarization state is substantially similar to the absorbing polarizer transmission polarization state.

3. An assembly as recited in claim 1, wherein the absorbing polarizer transmission polarization state is a linear polarization state and the first reflective polarizer transmission polarization state is a linear polarization state oriented within about 15°

of the absorbing polarizer transmission polarization state.

4. An assembly as recited in claim 1, wherein the first reflective polarizer includes a reflective linear polarizer.

5. An assembly as recited in claim 1, wherein the first reflective polarizer includes a reflective circular polarizer and a retarder layer disposed between the reflective circular polarizer and the absorbing polarizer.

6. An assembly as recited in claim 5, wherein the retarding layer is a quarter wave retarder.

7. An assembly as recited in claim 1, wherein the second reflective polarizer includes a reflective linear polarizer.

8. An assembly as recited in claim 7, wherein the absorbing polarizer transmission polarization state is a linear polarization state and the second reflective polarizer transmission polarization state is a linear polarization state non-parallel with the absorbing polarizer transmission polarization state.

9. An assembly as recited in claim 7, the second reflective polarizer including a passive polarization rotating layer between the reflective linear polarizer and the first reflective polarizer, the reflective linear polarizer defining a reflective linear polarizer transmission polarization state substantially parallel with the absorbing polarizer transmission polarization state.

10. An assembly as recited in claim 1, wherein the second reflective polarizer includes a reflective circular polarizer and a retarder layer disposed between the reflective circular polarizer and the first reflective polarizer.

11. An assembly as recited in claim 10, wherein the retarder layer is a quarter wave retarder.

12. An assembly as recited in claim 1, wherein the second reflective polarizer is a reflective elliptical polarizer.

13. An assembly as recited in claim 12, wherein the reflective elliptical polarizer includes an elliptical polarizer film having a film plane and helical cholesteric material aligned substantially non-perpendicular to the film plane.

14. An assembly as recited in claim 12, wherein the reflective elliptical polarizer includes an elliptical polarizer film having a film plane and helical cholesteric material aligned substantially perpendicular to the film plane, the elliptical polarizer film having first and second surfaces provided with light refracting layers to deviate light incident on the light refracting layers in a direction substantially perpendicular to the film plane into a direction passing through the elliptical polarizer film substantially non-perpendicular to the film plane.

15. An assembly as recited in claim 1, wherein at least one of the first and second reflective polarizers includes a diffusely reflecting polarizer.

16. An assembly as recited in claim 1, wherein the first and second reflective polarizers are linear reflective polarizers, a transmission polarization axis of the second reflective polarizer being oriented at an angle in the range 60°

to 90°

relative to a transmission polarization axis of the first reflective polarizer.

17. An assembly as recited in claim 1, further including an adhesive layer between at least one of i) the absorbing polarizer and the first reflective polarizer and ii) the first and second reflective polarizers.

18. An assembly as recited in claim 1, further including a diffusive layer between at least one of i) the absorbing polarizer and the first reflective polarizer and ii) the first and second reflective polarizers.

19. An assembly as recited in claim 1, further including a light steering layer disposed to steer light passing through the first reflective polarizer to the absorbing polarizer.

20. An assembly as recited in claim 1, further including a color filter layer disposed to absorb light of one wavelength passing through the absorbing polarizer and transmitting light at a different wavelength passing through the absorbing polarizer.

21. A passive transflective assembly for use in a display between a light modulator and a light source, the assembly comprising:

an absorbing polarizer disposed on a display side of the assembly;

a first reflective polarizer disposed on a light source side of the assembly to reflect at least a portion of light transmitted through the absorbing polarizer; and

a second reflective polarizer disposed between the absorbing polarizer and the first reflective polarizer, the second reflective polarizer reflecting light transmitted through the first reflective polarizer from the light source side of the assembly having a polarization absorbable in the absorbing polarizer, and the second reflective polarizer transmitting light transmitted through the absorbing polarizer towards the first reflective polarizer.

22. An assembly as recited in claim 21, wherein the second reflective polarizer is a linear reflecting polarizer having a polarization transmission axis oriented within 15°

of a polarization transmission axis of the absorbing polarizer.

23. An assembly as recited in claim 21, wherein the second reflective polarizer is a linear reflective polarizer having a polarization transmission axis oriented substantially parallel to a polarization transmission axis of the absorbing polarizer.

24. An assembly as recited in claim 21, wherein the second reflective polarizer reflects substantially all the light transmitted through the first reflective polarizer having a polarization absorbable in the absorbing polarizer.

25. An assembly as recited in claim 21, further comprising at least one diffusing layer disposed between the absorbing polarizer and the second reflective polarizer or between the first and second reflective polarizers.

26. An assembly as recited in claim 21, wherein the second reflective polarizer includes a cholesteric polarizer and a retarding layer between the cholesteric polarizer and the absorbing polarizer disposed to substantially minimize reflection by the cholesteric polarizer of light transmitted through the absorbing polarizer towards the second reflective polarizer.

27. An assembly as recited in claim 21, wherein the second reflective polarizer is a reflecting linear polarizer oriented to transmit substantially all light received from the absorbing polarizer.

28. An assembly as recited in claim 21, wherein the first reflective polarizer is a linear polarizer.

29. An assembly as recited in claim 28, wherein the first reflective polarizer is oriented to permit transmission, through the first reflective polarizer, of a portion of light received by the first reflective polarizer from the absorbing polarizer.

30. An assembly as recited in claim 28, wherein the first reflective polarizer is a linear reflective polarizer having a transmission polarization axis substantially parallel with a transmission polarization axis of the absorbing polarizer, and further comprising a passive birefringent retarding layer disposed between the first and second reflective polarizers, the birefringent retarding layer being oriented to rotate polarization of light propagating between the first and second reflective polarizers.

31. An assembly as recited in claim 21, wherein the first reflective polarizer includes a cholesteric polarizer.

32. An assembly as recited in claim 31, wherein the cholesteric polarizer is a reflective circular polarizer, and the first reflective polarizer further includes a retarding layer disposed between the cholesteric polarizer and the second reflective polarizer oriented to allow transmission, through the first reflective polarizer, of a portion of light received by the first reflective polarizer from the absorbing polarizer.

33. An assembly as recited in claim 31, wherein the cholesteric polarizer is a reflective elliptical polarizer oriented to allow transmission, through the first reflective polarizer, of a portion of light received by the first reflective polarizer from the absorbing polarizer.

34. An assembly as recited in claim 21, further comprising a light steering layer for steering light passing through the absorbing polarizer from the second reflective polarizer.

35. An assembly as recited in claim 21, further comprising a color filter layer disposed to absorb light at a first wavelength transmitted by the absorbing polarizer and to transmit light at a second wavelength transmitted by the absorbing polarizer.