Browse Prior Art Database

LIQUID CRYSTAL DISPLAY

IP.com Disclosure Number: IPCOM000023125D
Original Publication Date: 1976-Oct-31
Included in the Prior Art Database: 2004-Mar-27
Document File: 2 page(s) / 235K

Publishing Venue

Xerox Disclosure Journal

Abstract

The transformation of an optically negative liquid crystalline material to an optically positive state as disclosed in U.S. Patent 3,652,148 to Wysocki et al provides best image contrast when viewed between crossed polarizers,

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XEROX DISCLOSURE JOURNAL

LIQUID CRYSTAL DISPLAY Proposed Classification
Franklin D, Saeva U.S. Cl, 350/16OLC
mt. Ci, G02b 5/23

The transformation of an optically negative liquid
crystalline material to an optically positive state as
disclosed in U.S. Patent 3,652,148 to Wysocki et al
provides best image contrast when viewed between crossed
polarizers,

It is now reported that the addition of dichroic dyes
to the optically negative liquid crystalline material
permits colored contrast between image and background
areas which can be easily seen without the use of
crossed polarizers,

The alignment of the dichroic dye in the cholesteric
mesophase is altered in regions which are transformed
to the uniaxial nematic state, Large optical density
variations are observed between transformed and non~
trans formed regions,

Largest effects are provided by linear dichroic solutes
having electronic transitions polarized along their long
axis and also having their dipole moments along the same
axis, Examples of such solutes include:

o NH2

- -~--- ~

(Magenta) 0 0

o

H

/ \ / /

(Yellow) -\ 0 N=N ~ 0 )~--OH; and

CM
3 /~

(Cyan) -~ 0 =

CM
3'

Volume 1 Numbers 9/10 September/October 1976 61

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(cont~d)

Three color displays comprise three overlapping electro~
optic cells, one cell containing a cyan solute, one cell
containing a magenta solute and the remaining cell con~
taming a yellow solute.

62 XEROX DISCLOSURE JOURNAL

Volume 1 Numbers 9/10 Septe...