WAVELENGTH-CONVERTED SEMICONDUCTOR LIGHT EMITTING DEVICE

• US 20110062472A1
• Filed: 09/17/2009
• Published: 03/17/2011
• Est. Priority Date: 09/17/2009
• Status: Abandoned Application

• Current Assignee: Philips Lumileds Lighting Company LLC (Apollo Global Management, Inc.), Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Philips Lumileds Lighting Company LLC (Apollo Global Management, Inc.), Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: SHCHEKIN, Oleg B.
• Application Number:
  US12/561,759
• Publication Number:
  US 20110062472A1
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 33/02 characterised by the semiconductor bodies
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil

Abstract

A light emitting diode includes a semiconductor structure comprising a light emitting layer disposed between an n-type region and a p-type region, and n- and p-contacts disposed on the n- and p-type regions. The light emitting layer is configured to emit light of a first peak wavelength. A wavelength converting material is positioned in a path of light emitted by the light emitting layer. The wavelength converting material is configured to absorb light of the first peak wavelength and emit light of a second peak wavelength. The light emitting diode is configured such that a light emission pattern from the light emitting diode complements a light emission pattern from the wavelength converting material.

Claims

1. A device comprising:

a light emitting diode comprising;

semiconductor structure comprising a light emitting layer disposed between an n-type region and a p-type region, the light emitting layer being configured to emit light of a first peak wavelength; and

n- and p-contacts disposed on the n- and p-type regions; and

a wavelength converting material positioned in a path of light emitted by the light emitting layer, the wavelength converting material being configured to absorb light of the first peak wavelength and emit light of a second peak wavelength;

wherein the light emitting diode is configured such that a light emission pattern from the light emitting diode complements a light emission pattern from the wavelength converting material.

2. The device of claim 1 wherein the light emitting diode is configured such that at emission angles relative to a normal to a top surface of the device between 0°

and 50°

, a ratio of light emitted by the wavelength converting material normalized to a value at 0°

to unconverted light emitted by the light emitting layer normalized to a value at 0°

varies less than 15%.

3. The device of claim 1 wherein the light emitting diode is configured such that at emission angles relative to a normal to a top surface of the device between 0°

and 50°

, a ratio of light emitted by the wavelength converting material normalized to a value at 0°

to unconverted light emitted by the light emitting layer normalized to a value at 0°

varies less than 10%.

4. The device of claim 1 wherein the light emitting diode is configured such that at emission angles relative to a normal to a top surface of the device between 0°

and 50°

, a ratio of light emitted by the wavelength converting material normalized to a value at 0°

to unconverted light emitted by the light emitting layer normalized to a value at 0°

is less than 1.2.

5. The device of claim 1 wherein the light emitting diode is configured such that at emission angles relative to a normal to a top surface of the device between 0°

and 80°

, a ratio of light emitted by the wavelength converting material normalized to a value at 0°

to unconverted light emitted by the light emitting layer normalized to a value at 0°

varies less than 50%.

6. The device of claim 1 wherein the light emitting diode is configured such that at emission angles relative to a normal to a top surface of the device between 0°

and 80°

, a ratio of light emitted by the wavelength converting material normalized to a value at 0°

to unconverted light emitted by the light emitting layer normalized to a value at 0°

is less than 1.5.

7. The device of claim 1 wherein the n- and p-contacts are formed on a bottom surface of the semiconductor structure, the light emitting diode further comprising a photonic crystal formed in a top surface of the semiconductor structure.

8. The device of claim 7 wherein the photonic crystal is configured such that a light emission pattern from the light emitting diode complements a light emission pattern from the wavelength converting material.

9. The device of claim 1 wherein:

the light emitting diode further comprises a reflective surface; and

a spacing between the reflective surface and a center of the light emitting layer is configured such that a light emission pattern from the light emitting diode complements a light emission pattern from the wavelength converting material.

10. The device of claim 1 wherein:

the p-contact comprises silver; and

a spacing between a physical center of the light emitting layer and an interface between the p-contact and the p-type region is between 0.75λ and

0.85λ

, where λ

is the first peak wavelength in the light emitting diode.

11. The device of claim 1 wherein the wavelength converting material comprises a ceramic phosphor.

12. The device of claim 1 wherein the wavelength converting material comprises a powder phosphor disposed in a transparent material.