TRANSPARENT MIRRORLESS LIGHT EMITTING DIODE

• US 20100283078A1
• Filed: 07/14/2010
• Published: 11/11/2010
• Est. Priority Date: 11/15/2006
• Status: Abandoned Application

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Speck, James S., DenBaars, Steven P., Nakamura, Shuji
• Application Number:
  US12/836,348
• Publication Number:
  US 20100283078A1
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/16245 the item being metallic
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/49109 outside the semiconductor or solid-state body
• 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 2924/00014 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 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

An (Al, Ga, In)N light emitting diode (LED) in which multi-directional light can be extracted from one or more surfaces of the LED before entering a shaped optical element and subsequently being extracted to air. In particular, the (Al, Ga, In)N and transparent contact layers (such as ITO or ZnO) are embedded in or combined with a shaped optical element, which may be an epoxy, glass, silicon or other material molded into a sphere or inverted cone shape, wherein most of the light entering the inverted cone shape lies within a critical angle and is extracted. The present invention also minimizes internal reflections within the LED by eliminating mirrors and/or mirrored surfaces, in order to minimize re-absorption of the LED'"'"'s light by the emitting layer (or the active layer) of the LED. To assist in minimizing internal reflections, transparent electrodes, such as ITO or ZnO, may be used. Surface roughening by patterning or anisotropically etching (i.e., creating microcones) may also assist in light extraction, as well as minimizing internal reflections.

Claims

1. An opto-electronic device, comprising:

a light emitting diode (LED) chip that emits light out of the LED chip from two or more sides of the LED chip.

2. The device of claim 1, wherein the light is emitted out of the LED chip from front and back or top and bottom sides of the LED chip.

3. The device of claim 1, wherein one or more layers of the LED chip are shaped, patterned, textured or roughened to increase the light extraction.

4. The device of claim 1, wherein the LED chip is comprised of multiple emitting layers to generate the light at multiple wavelengths.

5. The device of claim 1, wherein the LED chip is embedded within a shaped optical element.

6. The device of claim 5, wherein the shaped optical element is shaped, patterned, textured or roughened to increase the light extraction.

7. The device of claim 5, wherein the shaped optical element is an inverted cone shape, and the light is reflected to a front surface of the inverted cone shape by side walls of the inverted cone shape positioned at a critical angle, so that the light is emitted through the front surface of the inverted cone shape.

8. The device of claim 5, wherein a phosphor layer is located on top of the shaped optical element, and the phosphor layer is shaped, patterned, textured or roughened to increase the light extraction.

9. The device of claim 1, wherein the LED chip resides in a lead frame that allows the light to be extracted from the two or more sides of the LED chip.

10. The device of claim 1, wherein the LED chip is mirrorless.

11. A method of fabricating an opto-electronic device, comprising:

creating a light emitting diode (LED) chip that emits light out of the LED chip from two more sides of the LED chip.

12. The method of claim 11, wherein the light is emitted out of the LED chip from front and back or top and bottom sides of the LED chip.

13. The method of claim 11, wherein one or more layers of the LED chip are shaped, patterned, textured or roughened to increase the light extraction.

14. The method of claim 11, wherein the LED chip is comprised of multiple emitting layers to generate the light at multiple wavelengths.

15. The method of claim 11, wherein the LED chip is embedded within a shaped optical element.

16. The method of claim 15, wherein the shaped optical element is shaped, patterned, textured or roughened to increase the light extraction.

17. The method of claim 15, wherein the shaped optical element is an inverted cone shape, and the light is reflected to a front surface of the inverted cone shape by side walls of the inverted cone shape positioned at a critical angle, so that the light is emitted through the front surface of the inverted cone shape.

18. The method of claim 15, wherein a phosphor layer is located on top of the shaped optical element, and the phosphor layer is shaped, patterned, textured or roughened to increase the light extraction.

19. The method of claim 11, wherein the LED chip resides in a lead frame that allows the light to be extracted from the two or more sides of the LED chip.

20. The method of claim 11, wherein the LED chip is mirrorless.