Light emitting display with light mixing within a film

• US 20110227487A1
• Filed: 04/18/2011
• Published: 09/22/2011
• Est. Priority Date: 10/09/2007
• Status: Active Grant

• Current Assignee: FLEx Lighting II, LLC
• Original Assignee: FLEx Lighting II, LLC
• Inventors: Nichol, Anthony, Coleman, Zane
• Granted Patent: US 8,434,909 B2
• Time in Patent Office: Days
• US Class Current: 315/158
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G02B 6/002 by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/006 to produce indicia, symbols, texts or the like
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0076 Stacked arrangements of multiple light guides of the same or different cross-sectional area
• CPC Class Codes: G02B 6/0078 Side-by-side arrangements, e.g. for large area displays
• CPC Class Codes: G02B 6/0085 Means for removing heat created by the light source from the package heat extraction or cooling elements for semiconductor light sources in general H01L33/64
• CPC Class Codes: Y10T 156/1051 by folding

Abstract

In one embodiment, a light emitting device comprises an array of legs extending from a body of film with the bounding edges of the legs stacked, a first light source emitting light of a first color and a second light source emitting light of a second color into the stacked bounding edges where the light emitting region defined within the body is configured to extract light of a third color. In another embodiment, a light emitting device comprises three light sources positioned to direct light into a stacked array of bounding edges. In one embodiment, a method of generating light of adjustable color exiting a surface of a film is disclosed.

Claims

1. A light emitting device comprising:

a. a light transmitting film having a body with opposing faces with a thickness not greater than 0.5 millimeters therebetween;

b. a first array of legs extending from the body of the film wherein;

i) each leg of the first array of legs comprises a first bounding edge at an end thereof; and

ii) each leg of the first array of legs is folded such that the first bounding edges are stacked;

c. a first light source positioned to emit light of a first color into the stacked first bounding edges;

d. a second light source positioned to emit light of a second color different than the first color into the stacked first bounding edges; and

e. a light emitting region defined within the body configured to extract light of a third color different than the first color and the second color when illuminated by light from the first light source and light from the second light source exiting the first array of legs, the light exiting the first array of legs propagating and mixing within the body in a waveguide condition.

2. The light emitting device of claim 1 wherein the light from the first light source and the light from the second light source mix within each leg.

3. The light emitting device of claim 1 further comprising a third light source positioned to emit light of a fourth color different than the first color and the second color into the stacked first bounding edges.

4. The light emitting device of claim 3 wherein the first color is substantially red, the second color is substantially green, and the fourth color is substantially blue.

5. The light emitting device of claim 1 wherein at least one of a first intensity of light from the first light source and a second intensity of light from the second light source is adjusted to emit light of a third color from the light emitting region.

6. The light emitting device of claim 1 further comprising a photosensitive element positioned to detect ambient light to facilitate adjusting an intensity of the light from the first light source in response to the ambient light detected.

7. A display comprising the light emitting device of claim 1 and a reflective spatial light modulator wherein the light emitting device is a frontlight for the reflective spatial light modulator.

8. The light emitting device of claim 1 further comprising a second array of legs extending from the body wherein:

a. each leg of the second array of legs comprises a second bounding edge at an end thereof;

b. the second array of legs are folded such that the second bounding edges are stacked; and

c. each of the second array of legs and the first array of legs extend from a first side of the body.

9. The light emitting device of claim 8 wherein the second array of legs are in a separate stack than the first array of legs.

10. The light emitting device of claim 8 further comprising a third light source positioned to emit light into the stacked second bounding edges such that the light propagates through the second array of legs and into the body in a waveguide condition.

11. The light emitting device of claim 10 wherein light from the first light source and light from the third light source mix in the body of the film.

12. A light emitting device comprising:

a. a first light source emitting light of substantially a first color;

b. a second light source emitting light of substantially a second color;

c. a third light source emitting light of substantially a third color;

d. a light transmitting film having a body with opposing faces with a thickness not greater than 0.5 millimeters therebetween;

e. at least one array of legs extending from the body of the film, wherein;

i) each leg of the at least one array of legs comprises a bounding edge at an end thereof; and

ii) the at least one array of legs are folded such that the bounding edges are stacked;

f. a light emitting region defined within the body configured to extract light propagating within the body in a waveguide condition,

wherein the first light source, the second light source, and the third light source are positioned to direct light into the stacked bounding edges of the at least one array of legs.

13. The light emitting device of claim 12 wherein the first color is red, the second color is blue, and the third color is green.

14. The light emitting device of claim 12 wherein light from the first light source, light from the second light source, and light from the third light source substantially mix within the at least one array of legs and the body.

15. The light emitting device of claim 12 wherein the relative intensities of the first light source and the second light source are adjusted to achieve light emitting from the light emitting region with a fourth color different from the first color and the second color.

16. A display comprising the light emitting device of claim 12 and a spatial light modulator wherein relative intensities of the light from each of the first light source, the second light source, and the third light source are adjusted to provide illumination for the spatial light modulator in a color sequential mode.

17. The display of claim 16 wherein the spatial light modulator is a reflective spatial light modulator and the light emitting device is a frontlight for the reflective spatial light modulator.

18. The display of claim 16 wherein the spatial light modulator is a transmissive spatial light modulator and the light emitting device is a backlight for the transmissive spatial light modulator.

19. A method of generating light of adjustable color exiting a surface of a film, said method comprising:

a. forming an array of legs extending from a body of the film, each leg of the array of legs forming a bounding edge at an end thereof;

b. folding the array of legs such that the bounding edges are stacked;

c. positioning a first light source and a second light source such that the light from the first light source and the light from the second light source mix within each leg and the body when the first light source and the second light source emit light simultaneously; and

d. adjusting at least one of a first intensity of the light from the first light source and a second intensity of the light from the second light source such that the light emitted from a light emitting region in the body changes color.

20. The method of claim 19 wherein the light from the first light source and the light from the second light source mix within at least one of the array of legs and the body.

21. The method of claim 19 further comprising positioning a third light source such that the third light source emits light into the stacked bounding edges and the light from the third light source mixes with the light from the first light source and the second light source in each leg and the body when the first light source, the second light source, and the third light source emit light simultaneously.

22. The method of claim 21 further comprising adjusting an intensity of the light from the first light source, an intensity of the light from the second light source, and an intensity of the light from the third light source in a color sequential mode.