Color graphic imager utilizing a liquid crystal display

A display apparatus comprising:

• a liquid crystal cell including
• (i) a supertwisted nematic liquid crystal material having a state of optical retardation variable only within a range between about 0.3 micrometers and 1.6 micrometers,
• (ii) a plurality of electrodes for applying an electric field across said liquid crystal material,
• (iii) a first polarizer at a viewing side of said cell
• (iv) a second polarizer on the side of said cell remote from said first polarizer, and
• (v) said liquid crystal material in said cell responding to different magnitudes of the electric field for the display of various perceived colors the majority of which fall outside an envelope defined by the following coordinates connected by straight lines on a 1931 C.I.E. chromaticity diagram:
• (x.congruent.0.25, y.congruent.0.17), (x.congruent.0.38, y.congruent.0.30), (x.congruent.0.40, y.congruent.0.38), (x.congruent.0.34, y.congruent.0.43), (x.congruent.0.23, y.congruent.0.35), and (x.congruent.0.19, y.congruent.0.18);
• said cell part of a panel positionable on a stage of an overhead projector, said panel having first and second transparent surfaces to establish a light path therethrough and said cell located therebetween;
• and
• means for interfacing said cell with a computer and for converting color display information produced by said computer to drive signals and means for applying said drive signals to said plurality of electrodes wherein different levels of average rms voltage are applied across selected ones of said electrodes to display said perceived color differences.

A display apparatus comprising:

• a liquid crystal cell including
• (i) a supertwisted liquid crystal material having a state of optical retardation variable within a range between about 0.3 micrometers and 1.6 micrometers for the display of at least four perceived color differences,
• (ii) an array of pixels arranged vertically in columns and horizontally in rows for applying an electric field across said liquid crystal material,
• (iii) a first polarizer at a viewing side of said cell,
• (iv) a second polarizer on the side of said cell remote from said first polarizer, and
• (v) said liquid crystal material in said cell responsive to different magnitudes of the electric field for the display of said perceived color differences;
• means for converting color display information produced by a computer and for applying time multiplexed signals to said pixels wherein different levels of average rms voltage are applied across said liquid crystal material by varying an on period relative to a frame period in order to display said perceived color differences;
• and
• said cell part of a panel for use with a projector including means for transmitting a light beam through said cell for forming an enlarged image of a display produced by said cell.

A display apparatus comprising:

• a liquid crystal cell including
• (i) a supertwisted nematic liquid crystal material having a state of optical retardation variable only within a range between about 0.3 microns and 1.6 microns,
• (ii) an array of pixels arranged vertically in columns and horizontally in rows for applying an electric field across said liquid crystal material,
• (iii) a first polarizer at a viewing side of said cell, and
• (iv) a second polarizer on the side of said cell remote from said first polarizer, and
• (v) said liquid crystal material in said cell responsive to different magnitudes of the electric field for the display of perceived color differences;
• means for converting color display information produced by a computer to a plurality of time multiplexed signals;
• and
• means for applying said time multiplexed signals to said array of pixels wherein different levels of average rms voltage are applied across selected ones of said pixels by varying an on period relative to a frame period in order to display said perceived color differences.

A display apparatus comprising:

• a liquid crystal cell including
• (i) a birefringent liquid crystal material having a state of optical retardation variable only within a range between about 0.3 .mu.m and 1.6 .mu.m.
• (ii) an array of pixels arranged vertically in columns and horizontally in rows for applying an electric field across said liquid crystal material,
• (iii) a first polarizer means at a viewing side of said cell, and
• (iv) a second polarizer means on the side of said cell remote from said first polarizer means, and
• (v) said liquid crystal material in said cell responsive to different magnitudes of the electric field for the display of perceived color differences;
• means for converting color display information produced by a computer to a plurality of signals;
• and
• means for applying said signals to said array of pixels wherein different levels of average rms voltage are applied across selected ones of said pixels in order to display said perceived color differences.

A display apparatus comprising:

• a liquid crystal cell including
• (i) a liquid crystal material having a state of optical retardation variable within a range between about 0.3 microns and 1.6 microns for the display of at least four perceived color differences,
• (ii) a plurality of electrodes for applying an electric field across said liquid crystal material,
• (iii) a first polarizer means at a viewing side of said cell,
• (iv) a second polarizer means on the side of said cell remote from said first polarizer means, and
• (v) said liquid crystal material in said cell responsive to different magnitudes of the electric field of the display of said perceived color differences;
• said cell part of a panel positionable on a stage of a projector, said panel having first and second transparent surfaces to establish a light path therethrough and said cell located therebetween;
• and
• means for interfacing said cell with a computer and for converting color display information produced by said computer to drive signals and means for applying said drive signals to said electrodes wherein different levels of average rms voltage are applied across selected ones of said electrodes to display said perceived color differences.