Illumination assembly including wavelength converting material having spatially varying density

• US 8,436,388 B2
• Filed: 08/24/2011
• Issued: 05/07/2013
• Est. Priority Date: 07/31/2007
• Status: Expired due to Fees

• Current Assignee: Rambus Delaware LLC (Rambus Inc.)
• Original Assignee: Rambus International Ltd (Rambus Inc.)
• Inventors: Lim, Michael, Doyle, David, Pokrovskiy, Alexander L, Taraschi, Gianni, Erchak, Alexei A, Nemchuk, Nikolay I
• Primary Examiner(s): Pizarro, Marcos D.
• Assistant Examiner(s): SKYLES, TIFNEY L
• Application Number:
  US13/216,837
• Publication Number:
  US 20110305002A1
• Time in Patent Office: 622 Days
• Field of Search: 257/98, 257/229, 257/294, 257/436, 257/440, 257/99
• US Class Current: 257/98
• 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 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources

Abstract

Illumination assemblies, components, and related methods are described. An illumination assembly can include at least one solid state light-emitting device, an emission surface through which light is emitted, and a wavelength converting material that wavelength converts at least some light emitted by the solid state light-emitting device. The wavelength converting material can have a first density per unit area of the emission surface at a first location and a second density per unit area of the emission surface at a second location, wherein the second density is substantially different from the first density, and wherein the density per unit area is defined with a 1×1 cm² averaging area. Another illumination assembly can include a light guide configured to receive light emitted by a solid state light-emitting device. The light guide can have a length along which received light propagates and an emission surface substantially parallel to the length of the light guide and through which light is emitted. A wavelength converting material can have a density per unit area of the emission surface that substantially increases along the length of the light guide.

Claims

1. A display assembly, comprising:

pixel light valves arranged in a layer;

a solid-state light-emitting device that outputs a primary light having a primary spectrum;

a light guide configured to receive the primary light emitted by the solid-state light-emitting device, the primary light propagating within the light guide and the light guide comprising a light emission surface juxtaposed with the layer of pixel light valves; and

first wavelength converting material regions and second wavelength converting material regions at the emission surface, the first wavelength converting material regions configured to convert the primary light incident thereon to a first converted light having a first converted wavelength spectrum and the second wavelength converting material regions configured to convert the primary light incident thereon to a second converted light having a second converted wavelength spectrum different from the first converted wavelength spectrum, each wavelength converting material region aligned with a respective pixel light valve and having a size approximately equal to a size of the respective pixel light valve so that the first converted light from the first wavelength converting material regions and the second converted light from the second wavelength converting material regions individually illuminate the respective pixel light valves.

2. The display assembly of claim 1, wherein the first converted light has a lower energy than the second converted light, and the second converted light has a lower energy than the primary light.

3. The display assembly of claim 2, wherein:

the first wavelength converting material regions comprise a first wavelength converting material that converts the primary light to red light;

the second wavelength converting material regions comprise a second wavelength converting material that converts the primary light to green light;

each first wavelength converting material region is aligned with a respective red pixel light valve of the pixel light valves; and

each second wavelength converting material region is aligned with a respective green pixel light valve of the pixel light valves.

4. The display assembly of claim 3, wherein the primary light is blue light, and the illumination assembly further includes light scattering features at the emission surface, the light scattering features aligned with and illuminating blue pixel light valves.

5. The display assembly of claim 1, wherein the primary light is ultraviolet light or blue light.

6. The display assembly of claim 1, additionally comprising third wavelength converting material regions at the emission surface, the third wavelength converting material regions configured to convert the primary light incident thereon to a third converted light having a third converted wavelength spectrum different from the first converted wavelength spectrum and different from the second converted wavelength spectrum, each third wavelength converting material region aligned with a respective pixel light valve and having a size approximately equal to a size of the respective pixel light valve so that the third converted light from the third wavelength converting material regions individually illuminate the respective pixel light valves.

7. The display assembly of claim 6, wherein the first converted light has a lower energy than the second converted light, the second converted light has a lower energy than the third converted light, and the third converted light has a lower energy than the primary light.

8. The display assembly of claim 7, wherein:

the first wavelength converting material regions comprise a first wavelength converting material that converts the primary light to red light;

the second wavelength converting material regions comprise a second wavelength converting material that converts the primary light to green light;

the third wavelength converting material regions comprise a third wavelength converting material that converts the primary light to blue light;

each first wavelength converting material region is aligned with a respective red pixel light valve of the pixel light valves;

each second wavelength converting material region is aligned with a respective green pixel light valve of the pixel light valves; and

each third wavelength converting material region is aligned with a respective blue pixel light valve of the pixel light valves.

9. The display assembly of claim 8, wherein the primary light is ultraviolet light.

10. The display assembly of claim 1, wherein the pixel light valves are liquid crystal light valves.

11. The display assembly of claim 10, wherein the display assembly does not include color filters.

12. The display assembly of claim 1, wherein at least one of the first wavelength converting material regions or the second wavelength converting material regions comprise quantum dots.

13. The display assembly of claim 1, wherein at least one of the first wavelength converting material regions or and the second wavelength converting material regions comprise a phosphor.

14. The display assembly of claim 1, wherein the solid-state light-emitting device comprises a light-emitting diode.

15. The display assembly of claim 1, wherein the solid-state light-emitting device comprises a laser diode.

16. The display assembly of claim 1, wherein at least some of the wavelength converting material regions are embodied as dots.

17. The display assembly of claim 1, wherein the light guide is generally rectangular in a plane parallel to the light emission surface and the light guide comprises a light input edge at a corner portion of the light guide through which the primary light emitted by the solid-state light-emitting device is received.

18. The display assembly of claim 17, wherein the light guide further comprises a light input edge at each corner and the illumination assembly further comprises a solid-state light-emitting device at each corner to input primary light into the light guide through each light input edge.