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Browse Prior Art Database

Illumination of Electrochromic Display

IP.com Disclosure Number: IPCOM000050736D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Bird, CL: AUTHOR [+3]

Abstract

This article concerns a technique for providing even flash illumination of the silicon wafer in an electrochromic display module.

This text was extracted from a PDF file.
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This is the abbreviated version, containing approximately 53% of the total text.

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Illumination of Electrochromic Display

This article concerns a technique for providing even flash illumination of the silicon wafer in an electrochromic display module.

The display module is shown to scale in cross-section in the figure and comprises a rectangular silicon wafer 1, typically having a length of 13.5 mm on its shortest side, a frame 2 of acrylic material sealed to the periphery of the wafer and forming a well containing electrochromic solution 3, and a glass-viewing window 4.

The illumination is provided by two flash tubes 5 disposed symmetrically along each long side of the wafer 1. The light from each tube 5, which may be considered to originate from a notional line source 6 at the center of the tube, enters each side of the frame 2 through a flat inclined face 7. The periphery of each tube 5 is provided with a reflective coating 8 which confines the light to emerge from the tube with an angle of spread which is just sufficient, after refraction at the face 7 and the internal walls 9 of the frame 2, to illuminate the full width of the wafer 1, each face 7 of the frame being disposed perpendicularly to the center ray 10 of each tube.

The principle involved is that the decreasing level of illumination provided across the surface of the wafer 1 by each flash tube 5 is supplemented by the increasing level of illumination provided by the other tube, so that the total illumination is substantially even. In particular we have found that the total illumination is most even and most intense, for a given distance of the sources 6 from the wafer, when the angle Theta which the outermost ray 11 from each tube 5 makes with the wafer 1 is c...