Compact High-Intensity LED Based Light Source

• US 20080158886A1
• Filed: 12/29/2006
• Published: 07/03/2008
• Est. Priority Date: 12/29/2006
• Status: Abandoned Application

• Current Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Chettiar, Shanmugam, Mok, Thye Linn, Pang, Siew It
• Application Number:
  US11/618,459
• Publication Number:
  US 20080158886A1
• Time in Patent Office: Days
• US Class Current: 362/294
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: H01L 2224/48091 Arched
• 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

Abstract

A light source having a plurality of dies, an LED carrier, and a cover. Each die includes an LED. The LED carrier includes a metallic core having a top and a bottom surface, the dies are bonded to a circuit layer on the top surface of the core. The cover is bonded to the LED carrier and includes an opening having reflective sides that allows light from the LEDs to leave the cover. A dome-shaped encapsulant layer covers each of the dies. The encapsulant layer is spaced from the sides of the opening such that there is an air gap between the encapsulant layers and the sides. The air gap is positioned such that light leaving the side surfaces of the dies passes through the air gap before being reflected by one of the sides.

Claims

1. A light source comprising:

a plurality of dies, each die comprising an LED, each die having a top surface, a bottom surface, and one or more side surfaces;

an LED carrier comprising a metallic core having a top and a bottom surface, said top surface being bonded to a circuit layer, said dies being bonded to said circuit layer;

a cover bonded to said LED carrier, said cover comprising a cavity therein, said metallic core of said LED carrier being at least partially positioned within said cavity, said cover further comprising a first opening that allows light from said LEDs to leave said cover, said opening having sides that slant inward such that light leaving a side surface of one of said dies is reflected by one of said sides out of said opening, said metallic core further comprising at least a portion thereof which is in direct contact with at least part of said cover; and

a dome-shaped encapsulant layer over each of said dies, said encapsulant layer being spaced from said sides of said opening such that there is an air gap between said encapsulant layer and said sides, said air gap being positioned such that light leaving said side surfaces of said dies passes through said air gap before being reflected by one of said sides.

2. The light source of claim 1 wherein said bottom surface of said metallic core comprises an external surface of said light source.

3. The light source of claim 1 wherein said circuit layer comprises mounting pads to which said dies are bonded and wherein said light source further comprises a connector that provides connections to circuit conductors connected to said mounting pads;

and a second opening in said cover that provides access to said connector.

4. The light source of claim 1 wherein said metallic core has a thermal conductivity greater than 10 W/m.K at 25 degrees Centigrade.

5. The light source of claim 1 wherein said cover comprises aluminum plated with nickel on a surface of said first opening.

6. The light source of claim 3 wherein said circuit layer comprises a thermally conductive insulator having a thickness of less than 4 mils having a first surface bonded to said metallic core and a second surface bonded to said circuit conductors.

7. The light source of claim 1 wherein said dome-shaped encapsulant comprises a first encapsulant having a material that converts light emitted by said LED encapsulated by said first encapsulant to light of a different wavelength and a second clear encapsulant overlying said first encapsulant.

8. The light source of claim 2 further comprising first and second holes in said cover and said LED carrier, said first and second holes in said cover being aligned with said first and second holes in said LED carrier such that said external surface of said light source is bonded to an external object when fasteners are connected through said holes and said external object.

9. The light source of claim 1 wherein said dies are arranged in a linear array having at least one row of LEDs that is parallel to one side of said first opening.