Package for multiple light emitting diodes

• US 8,716,725 B2
• Filed: 02/22/2013
• Issued: 05/06/2014
• Est. Priority Date: 04/08/2009
• Status: Active Grant

• Current Assignee: Ledengin, Inc. (Ams-Osram AG)
• Original Assignee: Ledengin, Inc. (Ams-Osram AG)
• Inventors: Yan, Xiantao
• Primary Examiner(s): ARORA, AJAY
• Application Number:
  US13/774,414
• Publication Number:
  US 20140049958A1
• Time in Patent Office: 438 Days
• Field of Search: 257/98, 257/88
• US Class Current: 257/88
• 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: H01L 2224/48091 Arched
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• 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 2924/19107 off-chip wires
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H01L 33/64 Heat extraction or cooling elements
• CPC Class Codes: H05K 1/0271 Arrangements for reducing stress or warp in rigid printed circuit boards, e.g. caused by loads, vibrations or differences in thermal expansion
• CPC Class Codes: H05K 1/0313 Organic insulating material
• CPC Class Codes: H05K 1/112 directly combined with via connections
• CPC Class Codes: H05K 1/181 associated with surface mounted components
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]
• CPC Class Codes: H05K 2201/2054 Light-reflecting surface, e.g. conductors, substrates, coatings, dielectrics

Abstract

Substrates and packages for LED-based light devices can significantly improve thermal performance and provide separate electrical and thermal paths through the substrate. One substrate includes multiple electrically insulating base layers. On a top one of these layers are disposed top-side electrical contacts, including light device pads to accommodate a plurality of light devices. External electrical contacts are disposed on an exterior surface of the substrate. Electrical paths connect the top-side electrical contacts to the external electrical contacts. At least portions of some of the electrical paths are disposed between the electrically insulating base layers. The electrical paths can be arranged such that different subsets of the light device pads are addressable independently of each other. A heat dissipation plate can be formed on the bottom surface of a bottom one of the base layers.

Claims

1. A lighting apparatus comprising:

a substrate having;

a plurality of electrically insulating base layers;

a plurality of external electrical contacts disposed on an exterior surface of the substrate;

a plurality of top-side pads including a plurality of light device pads and a plurality of auxiliary electrical bond pads, each light device bond pad being sized and positioned to accommodate a light device, each auxiliary electrical bond pad being sized and positioned to accommodate a wire bond; and

a plurality of electrical paths connecting at least some of the top-side pads to the external electrical contacts, wherein at least a portion of the plurality of electrical paths is disposed between the electrically insulating base layers; and

a plurality of light devices, each light device disposed on one of the light device pads, at least one of the light devices being connected via a wire bond to one of the auxiliary electrical contacts,

wherein the light devices are connected by the plurality of electrical paths in a plurality of independently addressable groups.

2. The lighting apparatus of claim 1 wherein at least one of the independently addressable groups includes at least two of the light devices.

3. The lighting apparatus of claim 1 wherein the number of auxiliary electrical bond pads is less than the number of light device bond pads.

4. The lighting apparatus of claim 1 wherein the number of auxiliary electrical bond pads is equal to the number of light device bond pads.

5. The lighting apparatus of claim 1 wherein the plurality of light devices includes a plurality of light-emitting diodes.

6. The lighting apparatus of claim 1 wherein the plurality of light devices includes at least twelve light-emitting diodes.

7. The lighting apparatus of claim 6 wherein the at least twelve light-emitting diodes are connected in two independently addressable groups.

8. The lighting apparatus of claim 1 wherein the light devices in a first one of the independently addressable groups are light devices that emit warm white light when operated and the light devices in a second one of the independently addressable groups are light devices that emit cool white light when operated.

9. The lighting apparatus of claim 1 wherein the plurality of top-side pads includes at least one pad that is sized and positioned to accommodate both a first one of the light devices and a wire bond to connect to a second one of the light devices.

10. The lighting apparatus of claim 1 further comprising a metal heat dissipation plate disposed on a bottom surface of the substrate, wherein the metal heat dissipation plate is electrically isolated from the plurality of electrical paths.

11. The lighting apparatus of claim 1 wherein an area of each of the light device pads is maximized subject to constraints of total area available for the light device pads and a minimum spacing between the light device pads to provide electrical isolation from each other.

12. The lighting apparatus of claim 1 further comprising at least one electrically insulating upper layer overlying the top one of the electrically insulating base layers, wherein each upper layer has an opening therethrough, the opening being sized and shaped such that at least a portion of each of the light device pads.

13. The lighting apparatus of claim 1 further comprising a primary lens overlying the plurality of light devices.