Light emitting device and fabrication method thereof

• US 20050184651A1
• Filed: 02/17/2005
• Published: 08/25/2005
• Est. Priority Date: 02/19/2004
• Status: Active Grant

• Current Assignee: HY-Tech Diode, LLC (Hong-Yuan Technology Co., Ltd.)
• Original Assignee: Hong-Yuan Technology Co., Ltd.
• Inventors: Cheng, Wei-Yuan, Wu, Yu-Chao
• Granted Patent: US 7,749,038 B2
• Time in Patent Office: Days
• US Class Current: 313/503
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/32257 the layer connector connecting to a bonding area disposed in a recess of the surface of the item
• 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 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 33/502 Wavelength conversion materials

Abstract

A light emitting device fabrication method. The fabrication method of the light emitting device comprises providing a light emitting semiconductor device; positioning a plurality of luminescent particles at the optical path of the light emitting semiconductor device; and reducing the distance between the luminescent particles to enhance the molecular attraction between the luminescent particles, than the luminescent particles is coagulated to a luminescent powder layer by the molecular attraction.

Claims

1. A light emitting device, comprising:

a light emitting semiconductor device; and

a luminescent powder layer which is adhesive material free, disposed on an optical path of the light emitting semiconductor device, wherein at least a part of the luminescent powder layer is coagulated.

2. The light emitting device as claimed in claim 1, wherein the luminescent powder layer comprises a plurality of luminescent particles, and the luminescent particles are coagulated by attraction of molecular interaction.

3. The light emitting device as claimed in claim 1, wherein the luminescent particles comprise powder phosphors.

4. The light emitting device as claimed in claim 2, wherein the luminescent powder layer is adhered to the light emitting semiconductor device.

5. A light emitting device fabrication method, comprising:

dispersing a plurality of luminescent particles in a liquid to form a mixture, wherein the liquid is adhesive material free;

positioning a substrate into the mixture for a period of time such that the luminescent particles precipitate on the substrate; and

removing the liquid to coagulate the luminescent particles as a luminescent powder layer adhering to the substrate.

6. The light emitting device fabrication method as claimed in claim 5, wherein the liquid comprise water or volatile solvent, which are free of epoxy resin and glue.

7. The light emitting device fabrication method as claimed in claim 6, wherein the volatile solvent comprises ethers, alcohols, ketones or combinations thereof.

8. The light emitting device fabrication method as claimed in claim 5, wherein the liquid is removed by a baking step, the baking step controlled at a temperature such that a perturbation of the liquid caused by the baking does not affect the arrangement of the luminescent particles on the substrate.

9. The light emitting device fabrication method as claimed in claim 5, wherein the method further comprises:

forming a first passivation layer at least cover a top surface of the luminescent powder layer; and

forming a second passivation layer at least cover the first passivation layer and the substrate.

10. The light emitting device fabrication method as claimed in claim 5, wherein the substrate comprises a light emitting diode.

11. A fabrication system of the light emitting device, comprising:

a container;

a disposal device for disposing a substrate to the container;

a liquid supply device for injecting a liquid into the container to a level higher than the substrate, wherein the liquid is free of adhesive;

a stirring device for uniformly dispersing a plurality of the luminescent particles in the liquid to form a mixture; and

a liquid removing device for removing the liquid after the luminescent particles precipitate on the substrate, thereby coagulating the luminescent particles adhering to the substrate.