MULTICHIP ON-BOARD LED ILLUMINATION DEVICE

• US 20090080184A1
• Filed: 12/05/2008
• Published: 03/26/2009
• 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
• Granted Patent: US 8,198,644 B2
• Time in Patent Office: Days
• US Class Current: 362/227
• 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. An illumination device, comprising:

a single red light emitting diode (LED);

a single blue LED;

one pair of green LEDs; and

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

a circuit layout operable to receive current from an external source and pass that current to an appropriate one of the red, blue, and pair of green LEDs for generating light.

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

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

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

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

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

8. An 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 pads;

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. An illumination device as recited in claim 9, wherein the four LED'"'"'s are packed within an area less than 9 mm².

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

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

13. An 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 pads;

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

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

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