Browse Prior Art Database

High Luminance Display Using a Large Area Light Amplifying Screen

IP.com Disclosure Number: IPCOM000123954D
Original Publication Date: 1999-Aug-01
Included in the Prior Art Database: 2005-Apr-05
Document File: 3 page(s) / 103K

Publishing Venue

IBM

Related People

Dove, DB: AUTHOR

Abstract

A new large screen display is described, having particularly high luminous efficiency, color, video capability and simple structure. The display consists of a large area flat panel containing on one side a layer of photoconducting material, a light blocking layer and on the other side, a layer of liquid crystal material that responds optically to an impressed voltage. An optical image is written onto the photoconductor side by means of a CRT or alternate method. When a voltage is applied between the 2 sides of the panel a distribution of voltage is transferred to the liquid crystal layer by virtue of the photoconductivity of the photoconducting input side layer.

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High Luminance Display Using a Large Area Light Amplifying Screen

   A new large screen display is described, having
particularly high luminous efficiency, color, video capability and
simple structure.  The display consists of a large area flat panel
containing on one side a layer of photoconducting material, a light
blocking layer and on the other side, a layer of liquid crystal
material that responds optically to an impressed voltage.  An optical
image is written onto the photoconductor side by means of a CRT or
alternate method.  When a voltage is applied between the 2 sides of
the panel a distribution of voltage is transferred to the liquid
crystal layer by virtue of the photoconductivity of the
photoconducting input side layer.  It can be noted that this
arrangement is that already well known as in the Hughes light valve,
but as previously conceived, consists of small devices typically of
one or several inches across, to be employed with a complicated
optical system that projects an image onto a distant screen with
attendant losses and problems.

   In the present display,  the device itself forms the
display screen and is of size several feet in diameter.  The display
is viewed from the liquid crystal layer side with illumination from
an external light source as illustrated in figure 1.  The liquid
crystal layer may be, for example, of the scattering type that
becomes clear in the presence of voltage.  When the layer is in the
scattering mode the screen appears to be white and is very bright
since it is illuminated directly by the external lamp.  The resulting
arrangement is therefore highly efficient and exceeds that achieved
for presently known methods.  When the liquid crystal is in the clear
state the incident light is absorbed by the black layer of the
display and
the display appears dark.   Other...