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Liquid Crystal Cell Having Nonuniform Thickness

IP.com Disclosure Number: IPCOM000077814D
Original Publication Date: 1972-Sep-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Ludeman, CP: AUTHOR [+2]

Abstract

A nonuniform thickness for liquid-crystal cells permit a variation of contrast across the face of the cell and also enhances apparent resolution in certain applications.

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Liquid Crystal Cell Having Nonuniform Thickness

A nonuniform thickness for liquid-crystal cells permit a variation of contrast across the face of the cell and also enhances apparent resolution in certain applications.

The degree of opaqueness (transmission mode) or the contrast ratio (reflective mode) of a liquid-crystal cell, is a function of the applied voltage and cell thickness. As the cell thickness varies the applied voltage gradient is changed, which alters the contrast ratio across the cell face. Depending upon cell design a wide variety of applications are available.

In Figs. 1A and 1B a rectangular cell comprises an electrically conductive, optically transparent plate 10, an electrically conductive plate 12 that is optically reflective for reflection mode or optically transparent for transmission mode, a spacer/insulator member 14 and liquid-crystal material, typically nematic. The rectangular cell provides maximum opaqueness at one end and decreases to 0 at the other end. Possible application would be as an analog indicating device, for example, a voltmeter, speedometer and the like. Several adjacent independent elements may be used as a histogram display.

A circular cell shown in Figs. 2A and 2B comprises the same elements as described in Figs. 1A and 1B. The opaqueness is maximum at the periphery of the cell and decreases to zero at the center. Possible application would be as a light intensity controller for electrical camera apertures and as a variable int...