Browse Prior Art Database

Laser Diode Liquid Crystal Video Display

IP.com Disclosure Number: IPCOM000086997D
Original Publication Date: 1976-Nov-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Johnson, DH: AUTHOR [+2]

Abstract

This display device (Fig. 1) incorporates a row of closely spaced laser diodes 10 aimed at a moving opaque surface comprised of liquid crystal material 12 sandwiched between two coated pieces of glass 14 and 16. The purpose of this configuration is to produce a flat, electronic video display that will be less expensive to build and require less circuitry to operate than present matrix addressable flat display designs.

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Laser Diode Liquid Crystal Video Display

This display device (Fig. 1) incorporates a row of closely spaced laser diodes 10 aimed at a moving opaque surface comprised of liquid crystal material 12 sandwiched between two coated pieces of glass 14 and 16. The purpose of this configuration is to produce a flat, electronic video display that will be less expensive to build and require less circuitry to operate than present matrix addressable flat display designs.

As shown in the side view of Fig. 2, the underside of the top sheet of glass 14 is coated with a high-resistivity, transparent metallic film 18, with low-resistance edge contacts brought out to two opposite edges 20 and 22 to which voltage va is applied. The topside of the bottom sheet of glass 16 is similarly coated, but with a low-resistivity metallic film 24 that is electrically grounded.

Voltage va, applied across the high resistivity coating 18, is a high-voltage ramp 26 (Fig. 4). Referring to Fig. 4, at any point in time, part 28 of the liquid crystal material will appear opaque and the remaining part 30 will appear transparent due to the voltage drop across the high resistivity coating and the resulting linear gradient in electric potential between points 20 and 22. Since liquid crystal material has a definite threshold at which an applied electric field will cause opacity, any applied va, which is large enough, will cause a fairly sharply defined edge or boundary 32 between the opaque and transparent ...