LED SOURCE WITH HOLLOW COLLECTION LENS

• US 20080048553A1
• Filed: 07/31/2007
• Published: 02/28/2008
• Est. Priority Date: 07/31/2006
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Company (3M Company)
• Inventors: Willett, Stephen, Destain, Patrick
• Granted Patent: US 8,115,384 B2
• Time in Patent Office: Days
• US Class Current: 313/499
• CPC Class Codes: G02B 19/0014 at least one surface having optical power
• CPC Class Codes: G02B 19/0061 the light source comprising a LED semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission H01L33/00
• CPC Class Codes: G02B 3/08 with discontinuous faces, e.g. Fresnel lens diffractive Fresnel lenses G02B5/1876
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A light source, includes an LED emitter and a meniscus lens having a hollow cavity in which the LED emitter is disposed. The meniscus lens is in exemplary embodiments hyperhemispheric, and it produces a high quality optical image of the LED emitter. The cavity of the lens is filled with air, such as terrestrial atmosphere, inert gas, or vacuum.

Claims

1. A light source, comprising:

an LED emitter; and

a meniscus lens having a hollow cavity;

wherein the LED emitter is disposed in the cavity.

2. The light source of claim 1, wherein the meniscus lens is hyperhemispheric.

3. The light source of claim 2, wherein the meniscus lens provides a virtual image of the LED emitter with little distortion.

4. The light source of claim 2, wherein the meniscus lens is composed of a material whose refractive index is at least 1.8.

5. The light source of claim 4, wherein the refractive index is at least 1.9.

6. The light source of claim 2, wherein the cavity is filled with a medium selected from the group of terrestrial atmosphere, an inert gas, or vacuum.

7. The light source of claim 2, further comprising a substrate on which the LED emitter is mounted, and wherein the meniscus lens is bonded to the substrate so that the cavity is sealed.

8. The light source of claim 2, wherein the LED emitter comprises a light extraction structure on an emitting surface thereof.

9. The light source of claim 8, wherein the light extraction structure comprises a photonic crystal structure or a wire grid extraction component.

10. The light source of claim 1, wherein the meniscus lens is composed of a material whose refractive index is at least 1.8.

11. The light source of claim 10, wherein the refractive index is at least 1.9.

12. The light source of claim 1, wherein the cavity is filled with a medium selected from the group of terrestrial atmosphere, an inert gas, or vacuum.

13. The light source of claim 1, further comprising a substrate on which the LED emitter is mounted, and wherein the meniscus lens is bonded to the substrate so that the cavity is sealed.

14. The light source of claim 1, wherein the LED emitter comprises a light extraction structure on an emitting surface thereof.

15. The light source of claim 14, wherein the light extraction structure comprises a photonic crystal structure or a wire grid extraction component.

16. The light source of claim 1, and further comprising:

a collimating lens positioned to receive light from the LED emitter through the meniscus lens;

a reflective polarizer positioned to receive light from the LED emitter through the collimating lens, the reflective polarizer transmitting therethrough collimated light having a first polarity, the reflective polarizer reflecting light having a second polarity back toward the LED emitter for light recycling.

17. The light source of claim 16, and further comprising a quarter wave plate positioned between the collimating lens and the reflective polarizer.

18. A projector comprising:

a light engine that provides a light beam, the light engine comprising an LED emitter and a meniscus lens having a hollow cavity, wherein the LED emitter is disposed in the cavity;

an image-forming device that receives image data and that receives at least a component of the light beam, the image-forming device providing an image; and

a projection lens assembly that receives the image and that provides an image projection beam.