Light emitting diode and method of making the same

• US 20040089864A1
• Filed: 03/26/2003
• Published: 05/13/2004
• Est. Priority Date: 11/08/2002
• Status: Abandoned Application

• Current Assignee: United Epitaxy Company (Epistar Corporation)
• Original Assignee: United Epitaxy Company (Epistar Corporation)
• Inventors: Tsai, Tzong-Liang, Chang, Chih-Sung, Chen, Tzer-Perng, Chi, Wu-Sheng
• Application Number:
  US10/396,821
• Publication Number:
  US 20040089864A1
• Time in Patent Office: Days
• US Class Current: 257/79
• CPC Class Codes: H01L 25/075 the devices being of a type provided for in group H01L33/00
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

The present invention provides a structure of white light-emitting diode (LED) and a method of making the same. The structure according to the present invention comprises two LED chips that have light-emitting layers of multi-layer epitaxial structure and emit the lights of one or more colors. The structure comprises an LED emitting the visible light of short wavelength, and another LED emitting the visible light of long wavelength. Wherein, at least one chip in the present invention has two or more transition energy levels used for emitting two or more colored lights. With the use of the present invention, multiple colored lights emitted by the LED can be mixed into full-spectral white light source having excellent color rendering property and high light emitting efficiency. The white LED in the present invention is an ideal light source for general-purpose illumination applications

Claims

1. A light emitting diode (LED), comprising:

a first LED chip, used for emitting a first visible light having a first light spectrum; and

a second LED chip, used for emitting a second visible light having a second light spectrum, wherein said first visible light is mixed with said second visible light to form a white light source;

wherein said first LED chip and/or said second LED chip have at least two transition energy levels, thereby emitting at least two colored lights.

2. The LED of claim 1, wherein said first LED chip is an AlInGaN LED chip.

3. The LED of claim 1, wherein said first LED chip is a ZnSe LED chip.

4. The LED of claim 1, wherein said second LED chip is an AlInGaP LED chip.

5. The LED of claim 1, wherein said second LED chip is an AlGaAs LED chip.

6. The LED of claim 1, wherein an active layer of said first LED chip and/or an active layer of said second LED chip are the structure of multiple quantum wells (MQWs).

7. The LED of claim 1, wherein an active layer of said first LED chip and/or an active layer of said second LED chip are formed by changing material composition to generate at least two transition energy levels, thereby emitting said at least two colored lights.

8. The LED of claim 1, wherein an active layer of said first LED chip and/or an active layer of said second LED chip are formed by changing quantum well width to generate at least two transition energy levels, thereby emitting said at least two colored lights.

9. The LED of claim 1, wherein an active layer of said first LED chip and/or an active layer of said second LED chip are formed by changing strain in the material to generate at least two transition energy levels, thereby emitting said at least two colored lights.

10. A method for making a LED, comprising:

providing a first LED chip, used for emitting a first visible light having a first light spectrum; and

providing a second LED chip, used for emitting a second visible light having a second light spectrum, wherein said first visible light is mixed with said second visible light to form a white light source;

wherein said first LED chip and/or said second LED chip have at least two transition energy levels, thereby emitting at least two colored lights.

11. The method for making the LED according to claim 10, wherein said first LED chip is an AlInGaN LED chip.

12. The method for making the LED according to claim 10, wherein said first LED chip is a ZnSe LED chip.

13. The method for making the LED according to claim 10, wherein said second LED chip is an AlInGaP LED chip.

14. The method for making the LED according to claim 10, wherein said second LED chip is an AlGaAs LED chip.

15. The method for making the LED according to claim 10, wherein an active layer of said first LED chip and/or an active layer of said second LED chip are the structure of multiple quantum wells (MQWs).

16. The method for making the LED according to claim 10, wherein an active layer of said first LED chip and/or an active layer of said second LED chip are formed by changing material composition to generate at least two transition energy levels, thereby emitting said at least two colored lights.

17. The method for making the LED according to claim 10, wherein an active layer of said first LED chip and/or an active layer of said second LED chip are formed by changing quantum well width to generate at least two transition energy levels, thereby emitting said at least two colored lights.

18. The method for making the LED according to claim 10, wherein an active layer of said first LED chip and/or an active layer of said second LED chip are formed by changing strain in the material to generate at least two transition energy levels, thereby emitting said at least two colored lights.