Light emitting device having integrated rectifier circuit in substrate

• US 7,148,515 B1
• Filed: 01/07/2006
• Issued: 12/12/2006
• Est. Priority Date: 01/07/2006
• Status: Active Grant

• Current Assignee: Tyntek Corporation
• Original Assignee: Tyntek Corporation
• Inventors: Chou, Wen-Long, Huang, Kuo-Jui, Sung, Chia-Pin
• Primary Examiner(s): Vo, Tuyet Thi
• Application Number:
  US11/326,706
• Time in Patent Office: 339 Days
• Field of Search: None
• US Class Current: 257/84
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• 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

A LED-based light emitting device having integrated rectifier circuit driven directly by an AC voltage and a related fabrication method is provided herein. The light emitting mainly contains a lower substrate and an upper substrate. The lower substrate has a built-in rectifier circuit and appropriate electrical contacts of the rectifier circuit are exposed on the top surface of the lower substrate. The upper substrate contains multiple LEDs arranged in an N×M array and the LEDs are all electrically insulated from each other. Metallic plating techniques are applied to establish electrical connection between these LEDs so that they jointly form a circuit matching the rectifier circuit on the lower substrate. The two substrates are faced towards each other and metallic bumps are applied to connect the LED circuit on the upper substrate to the rectifier circuit on the lower substrate, completing a fully function light emitting device.

Claims

1. A light emitting device integrating a rectifier circuit and a plurality of LEDs driven directly by an AC voltage, comprising:

a lower substrate having said rectifier circuit, said rectifier circuit having a plurality of first electrical contacts configured on the top surface of said lower substrate; and

an upper substrate having said LEDs mutually insulated and arranged in an N×

M (N, M≧

1) array, said LEDs being forward-connected in an appropriate topology by a plurality of electrical connections so as to form a load circuit matching to said rectifier circuit on said lower substrate, said load circuit having a plurality of second electrical contacts configured correspondingly to said first electrical contacts;

wherein said array of said LEDs are faced downward towards the top surface of said lower substrate; and

an appropriate electrical connection is established between corresponding pairs of said first electrical contacts and said second electrical contacts so as to complete the full circuit of said light emitting device.

2. The light emitting device according to claim 1, wherein said rectifying circuit is one of a bridge rectifying circuit, a full-wave rectifying circuit, and a half-wave rectifying circuit.

3. The light emitting device according to claim 1, wherein said appropriate topology of said LEDs is one of a series connection, a parallel connection, and a combination of series connections and parallel connections.

4. The light emitting device according to claim 1, wherein said lower substrate is a submount for said light emitting device in a subsequent packaging process.

5. The light emitting device according to claim 1, wherein said lower substrate further comprises a voltage reduction device located at an input end of said rectifier circuit.

6. The light emitting device according to claim 1, wherein said lower substrate further comprises a metallic thin layer configured on the bottom surface of said lower substrate.

7. The light emitting device according to claim 1, wherein said appropriate electrical connection between corresponding pairs of said first electrical contacts and said second electrical contacts is a metallic bump.

8. A fabrication method of a light emitting device integrating a rectifier circuit and a plurality of LEDs driven directly by an AC voltage, said fabrication method comprising the steps of:

(a) providing a lower substrate and an upper substrate wherein said rectifier circuit is formed in said lower substrate and a plurality of first electrical contacts of said rectifier circuit is configured on the top surface of said lower substrate using common integrated manufacturing methods, said LEDs are mutually insulated and arranged in an N×

M (N, M≧

1) array using common integrated circuit manufacturing methods, said LEDs are forward-connected in an appropriate topology by a plurality of electrical connections so as to form a load circuit, and said load circuit has a plurality of second electrical contacts configured correspondingly to said first electrical contacts; and

(b) joining each corresponding pairs of said first electrical contacts and said second electrical contacts by an appropriate electrical connection after facing said array of said LEDs downward towards the top surface of said lower substrate so as to complete the full circuit of said light emitting device.

9. The fabrication method to claim 8, wherein said rectifying circuit is one of a bridge rectifying circuit, a full-wave rectifying circuit, and a half-wave rectifying circuit.

10. The fabrication method according to claim 8, wherein said appropriate topology of said LEDs is one of a series connection, a parallel connection, and a combination of series connections and parallel connections.

11. The fabrication method according to claim 8, wherein said lower substrate is a submount for said light emitting device in a subsequent packaging process.

12. The fabrication method according to claim 8, wherein said step (a) further comprising:

forming a thin layer of highly thermal conductive material.

13. The fabrication method according to claim 8, wherein said appropriate electrical connection between corresponding pairs of said first electrical contacts and said second electrical contacts is a metallic bump.

14. The fabrication method according to claim 8, wherein said plurality of electrical connections between said LEDs are formed by one of the metallic evaporation method and the metallic sputtering method.

15. The fabrication method according to claim 13, wherein said first electrical contact and said second electrical contact are joined by said metallic bump by one of the supersonic method and the thermal eutectic method.

16. The fabrication method according to claim 12, wherein said thin layer of highly thermal conductive material is a metallic thin layer formed by one of the metallic evaporation method and the metallic sputtering method.