OPTICAL DEVICES USING REFLECTING POLARIZING MATERIALS

• US 20080013174A1
• Filed: 09/28/2007
• Published: 01/17/2008
• Est. Priority Date: 04/22/1999
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Allen, Richard, Ouderkirk, Andrew
• Application Number:
  US11/863,380
• Publication Number:
  US 20080013174A1
• Time in Patent Office: Days
• US Class Current: 359/487
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G02B 5/0236 the diffusion taking place within the volume of the element
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 5/0284 used in reflection
• CPC Class Codes: G02B 5/3033 in the form of a thin sheet or foil, e.g. Polaroid
• CPC Class Codes: G02B 5/3041 comprising multiple thin layers, e.g. multilayer stacks
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: Y10S 385/901 Illuminating or display apparatus

Abstract

Optical devices using reflective polarizers and, in particular, diffusely reflective polarizers are provided. Many of the optical devices utilize the diffusely reflecting and specularly transmitting properties of diffusely reflecting polarizers to enhance their optical characteristics. The optical devices include a lighting system which uses a reflector formed from a diffusely reflecting polarizer attached to a specular reflector. Another optical device is a display apparatus which uses a diffusely reflecting polarizer layer in combination with a turning lens which folds shallow angle light toward a light modulating layer. Other optical devices exploit the depolarizing characteristics of a diffusely reflecting polarizer when reflecting light. Still other optical devices use diffusely reflecting polarizers to recycle light and improve display illumination.

Claims

1. An optical device, comprising:

an information display comprising at least two emissive elements excitable in an addressable matrix to form an image; and

a contrast enhancing filter comprising a reflective polarizer disposed to receive light from the information display.

2. The device of claim 1, wherein the reflective polarizer is a diffusely reflective polarizer.

3. The device of claim 1, wherein the reflective polarizer is a multilayer reflective polarizer.

4. The device of claim 1, wherein the reflective polarizer is a cholesteric reflective polarizer.

5. The device of claim 1, wherein the contrast enhancing filter further comprises an absorbing polarizer.

6. The device of claim 5, wherein the absorbing polarizer is aligned with the reflective polarizer.

7. The device of claim 5, wherein the absorbing polarizer is laminated to the reflective polarizer.

8. The device of claim 1, wherein the reflective polarizer is attached to the information display.

9. The device of claim 1, wherein the reflective polarizer is attached to the at least two emissive elements.

10. The device of claim 1, wherein the at least two emissive elements are built directly onto the reflective polarizer.

11. The device of claim 1, further comprising a tinted layer.

12. The device of claim 1, wherein the at least two emissive elements comprise phosphor.

13. The device of claim 1, wherein the at least two emissive elements comprise light emitting diodes.

14. The device of claim 1, wherein the at least two emissive elements comprise fluorescent material.

15. The device of claim 1, wherein the information display is an electroluminescent display.

16. The device of claim 1, wherein the information display is a field emissive display.

17. The device of claim 1, wherein the information display is a plasma display.

18. The device of claim 1, wherein the information display is a light emitting diode display.