System and method for processing light in an electronic display system

• US 6,886,954 B2
• Filed: 12/23/2002
• Issued: 05/03/2005
• Est. Priority Date: 12/23/2002
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Williams, David L, Kardach, James P.
• Primary Examiner(s): O'Shea, Sandra
• Assistant Examiner(s): PAYNE, SHARON E
• Application Number:
  US10/326,162
• Publication Number:
  US 20040120137A1
• Time in Patent Office: 862 Days
• Field of Search: 359/494, 359/487, 359/599, 359/483, 359/485, 362/19, 362/31, 362/558, 362/559, 362/560, 362/561, 362/583, 362/217
• US Class Current: 362/19
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G02B 6/0021 for housing at least a part of the light source, e.g. by forming holes or recesses
• 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: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one

Abstract

Embodiments of the present invention relate to a device for polarizing light in a backlighting system of an electronic display to conserve energy. Embodiments of the invention may comprise an optically transparent material that includes an interface therein to separate randomly polarized light into vertically polarized and horizontally polarized components. The optically transparent material may have a re-polarizing layer thereon to change a polarization of one of the separated components, and a reflective edge disposed at an angle substantially parallel to the interface.

Claims

1. A device comprising:

an elongated pre-polarizing element including an optically transparent material having

an interlace therein to separate randomly polarized light into vertically polarized and horizontally polarized components;

a re-polarizing layer thereon to change a polarization of a first one of the separated components; and

a reflective edge to reflect a second one of the separated components;

the device further comprising a diffuser, wherein the elongated pre-polarizing element is arranged along an edge of the diffuser.

2. The device of claim 1, wherein the reflective edge is disposed at an angle substantially parallel to the interface.

3. The device of claim 1, wherein the optically transparent material is constituted at least in part by a box prism.

4. The device of claim 1, wherein the re-polarizing layer is a half-wave plate.

5. The device of claim 1, wherein the first one of the separated components is the horizontally polarized component, and the second one of the separated components is the vertically polarized component.

6. A device comprising:

an elongated pre-polarizing element including an optically transparent material having;

an interface therein;

a first outer edge, the interface being at a pre-determined angle with respect to the first outer edge;

a second outer edge having a re-polarizing layer thereon; and

a third outer edge having a reflective material thereon;

the device further comprising a diffuser, wherein the elongated pre-polarizing element is arranged along an edge of the diffuser.

7. The device of claim 6, wherein the pre-determined angle is approximately equal to Brewster'"'"'s angle for the material.

8. The device of claim 6, wherein the optically transparent material is constituted at least in part by a box prism.

9. The device of claim 6, wherein the re-polarizing layer is a half-wave plate.

10. An electronic display system comprising:

a light source;

a diffuser; and

a device arranged between the light source and the diffuser, the device including an elongated pre-polarizing element including an optically transparent material having

an interface therein to separate randomly polarized light into vertically polarized and horizontally polarized components;

a re-polarizing layer thereon to change a polarization of one of the separated components; and

a reflective edge to reflect the other separated component;

wherein the elongated pre-polarizing element is arranged along an edge of the diffuser.

11. The electronic display system of claim 10, further comprising a vertical polarizer.

12. The electronic display system of claim 10, further comprising a horizontal polarizer.

13. The electronic display system of claim 10, further comprising liquid crystal.

14. The electronic display system of claim 10, further comprising color absorption filters.

15. A device for polarizing light in an electronic display system, comprising:

diffusing means;

first means to pass horizontally polarized light in randomly polarized light from a light source, while reflecting vertically polarized light in the randomly polarized light;

second means to convert the horizontally polarized light passed by the first means into vertically polarized light; and

third means to direct the vertically polarized light reflected by the first means in a pre-determined direction;

wherein the first, second and third means are formed as an elongated member arranged along an edge of the diffusing means.

16. The device of claim 15, wherein the first means comprises a box prism.

17. The device of claim 15, wherein the second means comprises a half-wave plate.

18. A method for processing light in an electronic display system, comprising:

(i) arranging a diffuser and an elongated pre-polarizing element adjacent to a light source, wherein the elongated pre-polarizing element is disposed along an edge of the diffuser;

(ii) separating randomly polarized light from the light source using the elongated pre-polarizing element into a horizontally polarized component and a vertically polarized component;

(iii) converting the polarization type of a first one of the separated components into the polarization type of a second one of the separated components; and

(iv) directing both the converted component and the component not converted toward the diffuser.

19. The method of claim 18, wherein (ii) comprises passing the randomly polarized light through an optically transparent material of the elongated pre-polarizing element having an interface therein to separate randomly polarized light into vertically polarized and horizontally polarized components.

20. The method of claim 18, wherein (iii) comprises passing the first one of the separated components through a half-wave plate.

21. The method of claim 18, wherein (iv) comprises reflecting the second one of the separated components toward the diffuser.