Fractional coverage louver device for a light guide screen

• US 20070097690A1
• Filed: 11/01/2005
• Published: 05/03/2007
• Est. Priority Date: 11/01/2005
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Kuo, Huei, Hubby, Lawrence
• Granted Patent: US 7,535,638 B2
• Time in Patent Office: Days
• US Class Current: 362/290
• CPC Class Codes: G02B 6/08 with fibre bundle in form of plate
• CPC Class Codes: G03B 21/625 Lenticular translucent screens
• CPC Class Codes: H04N 5/7408 Direct viewing projectors, e.g. an image displayed on a video CRT or LCD display being projected on a screen
• CPC Class Codes: H04N 9/3141 Constructional details thereof details not peculiar to the presence of an electronic spatial light modulator G03B21/14
• CPC Class Codes: Y10S 385/901 Illuminating or display apparatus

Abstract

In a particular embodiment, the fractional coverage louver device includes a transparent layer of material having a first surface and a second surface parallel thereto. A plurality of louver members disposed within the transparent layer of material provide fractional reflective coverage across the width of the transparent material. The louver members are aligned to receive light entering the first surface at a shallow angle relative to the first surface and direct the light out the second surface at a high angle relative to the second surface, thereby increasing the angular viewing range. Transparent areas between louver members allow a portion of incident ambient light to pass through the louver device without being reflected back to a viewer. As such, the louver device has advantageous contrast properties.

Claims

1. A fractional coverage louver device for a light guide screen, comprising:

a transparent layer of material having a first surface and, parallel thereto, a second surface, and a width therebetween; and

a plurality of louver members disposed within the transparent layer of material, each louver member having a first end and a second end, the first end adjacent to the first surface, the second end proximate to the second surface and defining a space between the second end and the second surface.

2. The louver device of claim 1, wherein the louver members provide fractional reflective coverage across the width of the transparent layer.

3. The louver device of claim 1, wherein the transparent layer has a length, each louver member having a length less than the transparent layer length, such that the louver members provide fractional reflective coverage across the length of the transparent layer.

4. The louver device of claim 1, wherein the louver members present a fractional reflective area relative to a high angle of approach to the second surface.

5. The louver device of claim 1, wherein the louver members present a continuous reflective area relative to a low angle of approach to the first surface.

6. The louver device of claim 1, wherein the louver members are aligned to receive light entering the first surface at a shallow angle relative to the first surface and direct the light out the second surface at a high angle relative to the second surface.

7. The louver device of claim 1, wherein the louver members are physically reflective surfaces.

8. The louver device of claim 1, wherein the louver members are arranged in parallel rows.

9. The louver device of claim 1, wherein the louver members are shaped.

10. The louver device of claim 1, wherein each louver members is a cylindrical or elliptical mirror segment.

11. A fractional coverage louver device for a light guide screen, comprising:

a transparent layer of material having a first surface and, parallel thereto, a second surface, and a width therebetween;

a plurality of louver members disposed within the transparent layer of material adjacent to the first surface and extending toward the second surface across a fraction of the width of the transparent layer.

12. The louver device of claim 11, wherein the louver members present a fractional reflective area relative to a high angle of approach to the second surface.

13. The louver device of claim 11, wherein the transparent layer has a length, each louver member having a length less than the transparent layer length, such that the louver members provide fractional reflective coverage across the length of the transparent layer.

14. The louver device of claim 11, wherein the louver members present a continuous reflective area relative to a low angle of approach to the first surface.

15. The louver device of claim 11, wherein the louver members are aligned to receive light entering the first surface at a shallow angle relative to the first surface and direct the light out the second surface at a high angle relative to the second surface.

16. The louver device of claim 11, wherein the louver members are physically reflective surfaces.

17. The louver device of claim 11, wherein the louver members are arranged in parallel rows.

18. The louver device of claim 11, wherein the louver members are shaped.

19. The louver device of claim 11, wherein each louver member is a cylindrical or elliptical mirror segment.

20. The louver device of claim 11, wherein each louver member has a first end and a second end, the first end adjacent to the first surface, the second end defining a space between the second end and the second surface.

21. A fractional coverage louver device for a light guide screen, comprising:

a transparent layer of material having a first surface and, parallel thereto, a second surface, and a width therebetween;

a light redirection means for receiving light presented through the first surface at a first angle with a low angular range and increasing the angular range as the light is directed through the second surface at a plurality of angles relative to the second surface, the light redirection means disposed within the transparent layer adjacent to the first surface and occupying a fraction of the width.

22. The louver device of claim 21, wherein the means for receiving light and increasing angular range is a louver member.

23. A light guide display comprising:

a case;

a plurality of aligned magnifying layers within the case, each magnifying layer including a plurality of light guides, each light guide having a light transmitting core and an index of refraction, each light guide having an input end and an output end, the plurality of output ends collective grouped as an output location, the plurality of input ends collectively grouped as an input surface;

a transparent layer of material having a first surface adjacent to the output location and parallel thereto a second surface, and a width therebetween, the transparent layer of material having an index of refraction matched to the index of refraction of the light guide core;

a plurality of louver members disposed within the transparent layer of material, each louver member having a first end and a second end, the first end adjacent to the first surface, the second end proximate to the second surface and defining a space between the second end and the second surface; and

at least one image source proximate to the input surface.

24. The light guide display of claim 23, wherein each louver member is structured and arranged to accept light entering from the first surface with a narrow angular viewing range and provide the light through the second surface with an increased angular viewing range.

25. The light guide display of claim 23, wherein the louver members present a fractional reflective area relative to a high angle of approach to the second surface.

26. The light guide display of claim 23, wherein the louver members present a continuous reflective area relative to a low angle of approach to the first surface.

27. The light guide display of claim 23, wherein the louver members provide fractional reflective coverage across the width of the transparent layer.

28. The light guide display of claim 23, wherein the transparent layer has a length, each louver member having a length sufficient to transversely cross the output end adjacent to the louver, such that the louver members provide fractional reflective coverage across the length of the transparent layer.