Multichip on-board LED illumination device

• US 8,198,644 B2
• Filed: 12/05/2008
• Issued: 06/12/2012
• Est. Priority Date: 10/21/2005
• Status: Active Grant

• Current Assignee: Qioptiq Photonics GmbH & Company KG (Excelitas Technologies Holdings LLC)
• Original Assignee: Excelitas Technologies Elcos GmbH (Revvity, Inc.)
• Inventors: Kobilke, Siegmund
• Primary Examiner(s): PERT, EVAN T
• Application Number:
  US12/328,876
• Publication Number:
  US 20090080184A1
• Time in Patent Office: 1,285 Days
• Field of Search: 257/98, 257/89, 257/99, 257/100, 257/E33.056, 362/231, 362/252
• US Class Current: 257/89
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48472 the other connecting portion not on the bonding area also being a wedge bond, i.e. wedge-to-wedge
• 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 33/483 Containers
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/40 Details of LED load circuits

Abstract

An LED-based illumination device can use an array of four LEDs to produce high intensity light over a broad color spectrum and a broad range of color temperature. A high quality white light can be produced by using two green LEDs with a single red and a single blue LED.

Claims

1. A high intensity illumination device, comprising:

a single red light emitting diode (LED);

a single blue LED;

one pair of green LEDs;

a substrate supporting only the red, blue, and pair of green LEDs in a square array; and

a circuit layout configured to receive a desired current level from an external source corresponding to each LED color and pass an appropriate current level to each one of the red, blue, and pair of green LEDs for generating light.

2. The illumination device as recited in claim 1, wherein spacing between the LEDs is on the order of 0.1 mm.

3. The illumination device as recited in claim 1, wherein the four LEDs are packed within an area less than 9 mm².

4. The illumination device as recited in claim 1, wherein said substrate has a hexagonal configuration.

5. The illumination device as recited in claim 1, wherein the illumination pattern created by the LEDs is Lambertian.

6. The illumination device as recited in claim 1, wherein said green LEDs are connected in series and said external source provides selectable drive currents to the red LED, the blue LED chip, and the series-connected LEDs.

7. The illumination device as recited in claim 1, wherein drive current level supplied by the external source to the individual LEDs is variable to produce a selected color output.

8. The illumination device as recited in claim 1, wherein said LEDs are sealed with an encapsulant.

9. An illumination device, comprising:

a substrate;

a circuit layout positioned on the substrate, the circuit layout including a plurality of anode and cathode pad pairs;

a square array of four closely packed LEDs supported by the substrate and electrically connected to the circuit layout in order to allow activation through the application of current to an appropriate pair of the plurality of anode and cathode pads; and

an encapsulant positioned over the square array of four LEDs to prevent external contact with the square array while out coupling light from the square array.

10. The illumination device as recited in claim 9, wherein the four LEDs are packed within an area less than 9 mm².

11. The illumination device as recited in claim 9, wherein spacing between the LEDs is on the order of 0.1 mm.

12. The illumination device as recited in claim 9, wherein said substrate has a hexagonal configuration.

13. The illumination device as recited in claim 9, wherein the illumination pattern created by the LEDs is Lambertian.

14. An illumination device, comprising:

a substrate;

a circuit layout positioned on the substrate, the circuit layout including a plurality of anode and cathode pad pairs;

a square array of four closely packed diodes supported by the substrate and electrically connected to the circuit layout via an associated pair of the plurality of anode and cathode pads, wherein at least three of the diodes are light emitting diodes; and

an encapsulant positioned over the square array of four diodes to prevent external contact with the square array while out coupling light from the square array.

15. The illumination device as recited in claim 14, wherein the four diodes are packed within an area less than 9 mm².

16. The illumination device as recited in claim 14, wherein spacing between the diodes is on the order of 0.1 mm.

17. The illumination device as recited in claim 14, wherein said substrate has a hexagonal configuration.

18. An illumination device comprising:

a substrate;

a set of four LEDs supported by the substrate and arranged in a two by two array in a manner such that the light emitted therefrom is mixed together, said LEDs including at least one red LED, one green LED and one blue LED; and

electrical contacts for individually supplying each of the red, green and blue LEDs with a selected current level, with the particular currents supplied to each LED being selected so that the mixed light corresponds to a particular color output.

19. The illumination device as recited in claim 18 wherein the fourth LED is a green LED.

20. The illumination device as recited in claim 18 wherein the currents supplied to the LEDs are selected so that the mixed light is white.

21. The illumination device as recited in claim 18, wherein spacing between the LEDs is on the order of 0.1 mm.

22. The illumination device as recited in claim 18, wherein the four LEDs are packed within an area less than 9 mm².