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Staggered dual sided flood LED Illumination architecture

IP.com Disclosure Number: IPCOM000188420D
Publication Date: 2009-Oct-06
Document File: 2 page(s) / 92K

Publishing Venue

The IP.com Prior Art Database

Abstract

Illumination uniformity is an important performance metric when designing an illumination system. This idea describes an illumination system for illuminating small areas on a surface, such as for scanning images on sheets or optical inspection of surfaces. In such a flood illumination system utilizing LEDs (Light Emitting Diode), this is generally achieved by increasing the device density. Due to physical considerations of device size, there is a limit to the density that can be achieved. In addition, increasing device density increases the thermal load and cost. This idea proposes an LED illumination system with two LED arrays arranged symmetrically with respect to the point to be illuminated. One bar is shifted in its long direction by one-half the spacing of adjacent LED's. The claimed benefit of this arrangement is to reduce the illumination non-uniformity by filling in valleys in one illumination profile with peaks in the other. A second advantage of using two arrays is lower power operation of the component arrays.

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Staggered dual sided flood LED Illumination architecture

Illumination uniformity is an important performance metric when designing an illumination system.  This idea describes an illumination system for illuminating small areas on a surface, such as for scanning images on sheets or optical inspection of surfaces.  In such a flood illumination system utilizing LEDs (Light Emitting Diode), this is generally achieved by increasing the device density. Due to physical considerations of device size, there is a limit to the density that can be achieved. In addition, increasing device density increases the thermal load and cost. This idea proposes an LED illumination system with two LED arrays arranged symmetrically with respect to the point to be illuminated. One bar is shifted in its long direction by one-half the spacing of adjacent LED's. The claimed benefit of this arrangement is to reduce the illumination non-uniformity by filling in valleys in one illumination profile with peaks in the other. A second advantage of using two arrays is lower power operation of the component arrays.

For purposes of illustration, a system utilizing the Seoul MWT801S package device will be discussed. The Seoul MWT801S is a fairly typical packaged white LED. It consists of a blue die which pumps a “white” phosphor. The device measures 3.2mmx2.8mm (W x L). A c...