Light emitting diode arrays with improved light extraction

a technology of light extraction and led arrays, applied in the direction of discharge tubes, luminescnet screens, identification means, etc., can solve the problems of significant heat generated by dense concentrations of leds, illumination efficiency, and self-heating by absorption, and achieve the effect of improving illumination efficiency and reducing thermal problems

Inactive Publication Date: 2005-10-13
LAMINA CERAMICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

One problem with LED arrays is the significant heat generated by dense concentrations of LEDs.
Another problem in LED arrays concerns illumination efficiency.
Self-heating by absorption contributes to thermal problems.

Method used

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  • Light emitting diode arrays with improved light extraction
  • Light emitting diode arrays with improved light extraction
  • Light emitting diode arrays with improved light extraction

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Embodiment Construction

[0016] This description is divided into two parts. Part I describes the structure and features of light emitting diodes (LEDs) packaged in an array for high illumination efficiency in accordance with the invention and illustrate exemplary embodiments. Part II provides further details of the LTCC-M packaging technology as applicable to LED arrays.

I. LEDs Packaged for High Illumination Efficiency

[0017]FIG. 4 illustrates, a tapered barrier reflector 40 fabricated as a periodic array of troughs 41 and tapered reflective ridges 42. This accordion-like structure is a particularly cost effective to manufacture. Metal reflective material can be folded in an accordion-like manner to form the tapered reflective barriers 42. LED dies 12 can be affixed in the troughs 43 between reflective barriers 42.

[0018] The barrier reflector 40 can provide a connection to the anode or cathode of LED dies 12. The barrier 40 also serves a thermal cooling function. Heat from the LED die 12 can be channeled...

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PUM

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Abstract

In accordance with the invention, an illumination device comprises a highly thermally conductive substrate having a surface, a plurality of light emitting diodes (LEDs) supported by the surface and arranged in an array to provide illumination. At least one reflective barrier at least partially surrounds each LED. The reflective barrier is shaped to reflect away from the LED light emitted by other LEDs in the array. Advantageously the substrate and reflective barrier are thermally coupled to a heat spreader to dissipate heat generated by the LEDs. The substrate preferably comprises an LTTC-M heat spreader, and the reflective thermal barriers preferably comprise metal ridges or cups.

Description

FIELD OF THE INVENTION [0001] This invention relates to light emitting diode (LED) arrays and, in particular, to LED arrays with integral reflective barriers and methods for making same. BACKGROUND OF THE INVENTION [0002] Light emitting diodes (LEDs) are being used as light sources in an increasing variety of applications extending from communications and instrumentation to household, automotive and other visual displays. LED arrays comprise a plurality of LEDs arranged on a common substrate. One problem with LED arrays is the significant heat generated by dense concentrations of LEDs. Solutions to the thermal problems associated with LED arrays are the subject of a related application entitled, “Light Emitting Diodes Packaged For High Temperature Operation” U.S. patent application Ser. No. 10 / 638,579, filed Aug. 11, 2003. The Ser. No. 10 / 630,579 application is incorporated herein by reference. [0003] Another problem in LED arrays concerns illumination efficiency. Illumination effic...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): F21K99/00H01J1/62H01L33/60H01L33/62
CPCG09F9/33H01L33/60H01L33/62H01L2224/32225H01L2224/48091H01L2224/48227H01L2224/48472H01L2224/73265H01L2924/01004H01L2924/01012H01L2924/0102H01L2924/01025H01L2924/01057H01L2924/01079H01L2924/09701H01L2924/19041H01L2924/00014H01L2924/12041H01L2924/00F21K9/68
Inventor MAZZOCHETTE, JOSEPHAMAYA, EDMAR
Owner LAMINA CERAMICS
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