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BIREFRINGENT FILTER TO IMPROVE UNIFORMITY OF A WRITE BAR

IP.com Disclosure Number: IPCOM000025993D
Original Publication Date: 1989-Aug-31
Included in the Prior Art Database: 2004-Apr-05
Document File: 2 page(s) / 52K

Publishing Venue

Xerox Disclosure Journal

Abstract

High resolution (300 to 600 pixeldinch) LED write bars exhibit a "ripple" in their axial profile due to the physical separation of the light-emitting elements. This ri ple can be significantly reduced by use of a thin layer of

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XEROX DISCLOSURE JOURNAL

BIREFRINGENT FILTER TO Proposed Classification IMPROVE UNIFORMITY OF A
WRITE BAR
Ronald E. Godlove

U.S. C1.346/160 Int. C1. Gold 15/14

High resolution (300 to 600 pixeldinch) LED write bars exhibit a "ripple" in their axial profile due to the physical separation of the light-emitting elements. This ri ple can be significantly reduced by use of a thin layer of

Selection of the proper thickness of this filter will result in superposition of the peaks of the extraordinary out ut rays over the valleys of the ordinary output

a uniform output. As one example, assuming that the LED pixels are 50 microns wide and spaced apart by 35 microns, the thickness of the birefringent material must be such as to provide a 35 micron displacement of the ordinary rays. This will reduce the ripple effect to as low as 25% with little loss in exposure. The ri le can be completely eliminated if the displacement is made equal to one harrof the period of the LED (85 microns) but some loss of resolution will be experienced.

transparent bire P ringent material placed over the LED bar structure.

rays and vice versa thus cance

P ling out the peaks and valleys and resulting in

Volume 14 Number 4 July/August 1989 179

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180 XEROX DISCLOSURE JOURNAL

Volume 14 Number 4 July/August 1989

[This page contains 1 picture or other non-text object]