Optical platform to enable efficient LED emission

• US 7,839,062 B2
• Filed: 08/29/2008
• Issued: 11/23/2010
• Est. Priority Date: 08/29/2008
• Status: Active Grant

• Current Assignee: Bridgelux Incorporated
• Original Assignee: Bridgelux Incorporated
• Inventors: Shum, Frank
• Primary Examiner(s): Ward; John A
• Application Number:
  US12/201,936
• Publication Number:
  US 20100053980A1
• Time in Patent Office: 816 Days
• Field of Search: 362/311.02, 313110-112, 313/512, 257/98, 257/E33.073, 257/E33.074, 438/31, 438/32
• US Class Current: 313/110
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

An integrated multi-layer apparatus and method of producing the same is disclosed. The apparatus comprises an LED, a beam shaping layer, and a refracting layer between the beam shaping layer from the LED. The refracting layer may have an index of refraction lower than the index of refraction of the LED and the beam shaping layer.

Claims

1. An integrated multi-layer apparatus, comprising:

an LED configured to emit light having a first portion emitted within an angular range and a second portion emitted outside the angular range;

a beam shaping layer configured to pass the first portion of the emitted light and reflect the second portion of the emitted light back to the LED; and

a refracting layer between the beam shaping layer and the LED, the refracting layer having an index of refraction lower than the index of refraction of the LED and the beam shaping layer;

wherein the LED is further configured to randomly scatter the second portion of the emitted light reflected from the beam shaping layer and redirect the scattered light back to the beam shaping layer.

2. The apparatus of claim 1 wherein the beam shaping layer comprises periodic optical structures.

3. The apparatus of claim 1 wherein the beam shaping layer comprises at least one of a lens, mirror, or prism.

4. The apparatus of claim 1 wherein the beam shaping layer and the LED are arranged to avoid any direct couplings between the two.

5. The apparatus of claim 1 wherein the refracting layer separates the beam shaping layer from the LED by at least 1 λ

/nL.

6. The apparatus of claim 1 wherein the refracting layer comprises air.

7. The apparatus of claim 1 wherein the LED further comprises a roughened surface to randomly scatter the second portion of the emitted light reflected from the beam shaping layer.

8. The apparatus of claim 1 wherein the LED further comprises a back reflector to redirect the scattered light back to the beam shaping layer.

9. An integrated multi-layer apparatus, comprising:

an LED configured to emit light having a first portion emitted within an angular range and a second portion emitted outside the angular range;

a beam shaping layer configured to pass the first portion of the emitted light and reflect the second portion of the emitted light back to the LED; and

a refracting layer between the beam shaping layer and the LED, the refracting layer having an index of refraction lower than the index of refraction of the LED and the beam shaping layer;

wherein the LED further comprises a roughened surface and a back reflector.

10. The apparatus of claim 9 wherein the beam shaping layer comprises periodic optical structures.

11. The apparatus of claim 9 wherein the beam shaping layer comprises at least one of a lens, mirror, or prism.

12. The apparatus of claim 9 wherein the beam shaping layer and the LED are arranged to avoid any direct couplings between the two.

13. The apparatus of claim 9 wherein the refracting layer separates the beam shaping layer from the LED by at least 1 λ

/nL.

14. The apparatus of claim 9 wherein the refracting layer comprises air.

15. An integrated multi-layer apparatus, comprising:

light emitting means for emitting light, wherein the light includes a first portion emitted within an angular range and a second portion emitted outside the angular range;

beam shaping means for passing the first portion of the emitted light and reflecting the second portion of the emitted light back to the light emitting means; and

refracting means for refracting the emitted light, the refracting means having an index of refraction lower than the index of refraction of the light emitting means and the beam shaping means;

wherein the light emitting means comprises means for randomly scattering the second portion of the emitted light reflected by the beam shaping means and means for redirecting the scattered light back to the beam shaping means.

16. The apparatus of claim 15 wherein the beam shaping means comprises periodic optical structures.

17. The apparatus of claim 15 wherein the beam shaping means and the light emitting means are arranged to avoid any direct couplings between the two.

18. The apparatus of claim 15 wherein the refracting means separates the beam shaping means from the light emitting means by at least 1 λ

/nL.

19. The apparatus of claim 15 wherein the light emitting means comprises a light emitting diode (LED) having a roughened surface, and wherein the means for randomly scattering the second portion of the emitted light comprises the roughened surface of the LED.

20. The apparatus of claim 15 wherein the light emitting means comprises a light emitting diode (LED) having a back reflector, and wherein the means for redirecting the scattered light back to the beam shaping means comprises the back reflector.