Method and apparatus for multi-mode image display with a liquid crystal light valve

Claim 1

In a method of displaying an image wherein a writing light input image modulates a polarized projection beam with an electric field driven hybrid field effect liquid crystal light valve, said light valve having a nematic liquid crystal structure helically twisted through an acute angle, the multi-mode field effect improvement comprising the steps of : a) orienting the polarization direction of said projection beam incident on said light valve to fall within said acute angle of said liquid crystal structure; and b) adjusting the magnitude of said electric field applied across said liquid crystal layer so that predetermined intensity levels of said input image modulate said projection bean to produce either a simultaneous display of color symbology and achromatic gray scale images or a separate display of either one of them.

Claim 9

The method as in Claims 1, 2, 3 or 4 wherein said projection beam polarization direction bisects said acute angle.

Claim 10

The method as in Claims 1, 2, 3 or 4 wherein said acute angle is 45°.

Claim 11

A system for displaying an image wherein a writing light input image modulates a polarized projection beam with an electric field driven hybrid field effect liquid crystal light valve, said light valve having a nematic liquid crystal structure helically twisted through an acute angle, said system being characterized by improvements for producing either a simultaneous display of color symbology and achromatic gray scale images or a separate display of either one of them, said improvements residing in: a) means for orientinq the polarization direction of said projection light incident on said light valve to fall within said acute angle of said liquid crystal structure; and b) means for adjusting the magnitude of said electric field applied across said liquid crystal layer to at least first and second fixed values, such that 1) the first fixed value produces i) a multicolor output image and, ii) an achromatic gray scale output image, and, 2) the second fixed value produces an achromatic gray scale output image.

Claim 12

A system for displaying an image wherein a writing light input image modulates a polarized projection beam with an electric field driven hybrid field effect liquid crystal light valve, said light valve having a nematic liquid crystal structure helically twisted through an acute angle, said system being characterized by improvements for producing either a simultaneous display of color symbology and achromatic gray scale images or a separate display of either one of them, said improvements residing in: a) means for orientinq the polarization direction of said projection light incident on said light valve to fall within said acute angle of said liquid crystal structure; and b) means for adjusting the magnitude of said electric field applied across said liquid crystal layer to at least first and second fixed values, such that 1) the first fixed value produces i) a multicolor output image and, ii) an achromatic gray scale output image, and, 2) the second fixed value produces an achromatic gray scale output image.

Claim 13

A system for displaying an image wherein a writing light input image modulates a polarized projection beam with an electric field driven hybrid field effect liquid crystal light valve, said light valve having a nematic liquid crystal structure helically twisted through an acute angle, said system being characterized by improvements for producing either a simultaneous display of color symbology and achromatic gray scale images or a separate display of either one of them, said improvements residing in: a) means for orienting the polarization direction of said projection light incident on said light valve to fall within said acute angle of said liquid crystal structure; and b) means for adjusting the magnitude of said electric field applied across said liquid crystal layer to at least first and second fixed values, said second value being greater than said first value, 1) the first fixed value being such that a writing light input image having first and second intensity ranges, wherein the intensity levels of said second range are greater than the intensity levels of said first range, results in said projection beam displaying; i) a multicolor output image whose colors are a function of said first intensity range, and ii) an achromatic gray scale output image whose intensity range is a function of said second intensity range, 2) the second fixed value of said electric field being such that a writing light input image having a given intensity range results in said projection beam displaying an achromatic gray scale output image whose intensity range is a function of said given intensity range.

Claim 14

A system for displaying an image wherein a writing light input image modulates a polarized projection beam with an electric field driven hybrid field effect liquid crystal light valve, said light valve having a nematic liquid crystal structure helically twisted through an acute angle, said system being characterized by improvements for producing either a simultaneous display of color symbology and achromatic gray scale images or a separate display of either one of them, said improvements residing in: a) means for orienting the polarization direction of said projection light incident on said light valve to fall within said acute angle of said liquid crystal structure; and b) means for adjusting the magnitude of said electric field applied across said liquid crystal layer to at least first and second fixed values, said second value being greater than said first value, 1) the first fixed value being such that a writing light input image having first and second intensity ranges, wherein the intensity levels of said second range are greater than the intensity levels of said first range, results in said projection beam displaying; i) a multicolor output image whose colors are a function of said first intensity range, and ii) an achromatic gray scale output image whose intensity range is a function of said second intensity range, 2) the second fixed value of said electric field being such that a writing light input image having a given intensity range results in said projection beam displaying an achromatic gray scale output image whose intensity range is a function of said given intensity range.

Claim 15

A system for displaying an image having: A) an electric field driven liquid crystal light valve of the type having a plurality of adjacent functional layers arranged in the sequential order of; B) a first transparent conductive electrode, a reflective layer, a photoresponsive layer, a first transparent insulating layer, a nematic liquid crystal layer characterized by first and second surfaces, a second transparent insulating layer and a second transparent conductive electrode, %? herein said liquid crystal layer is characterized by a molecular structure such that, in the absence of said electric field, the long axes of the liquid crystal molecules are in spirally twisted alignment with respect to one another, molecules adjacent to said first surface having said axes oriented in a first direction parallel to said first surface, and molecules adjacent to said second surface have said axes oriented in a second direction parallel to said second surface so that said first and second directions intersect at an acute angle when orthogonally projected onto a plane parallel to either of said surfaces; C) means for applying an alternating electric field across said first and second electrodes; D) means for projecting polarized projection light through said second transparent electrode in order to traverse said liquid crystal layer, reflect from said reflecting means, and retraverse said layers; E) means for projecting external writing light images through said first transparent electrode onto said photoresponsive layer, and F) means for transmitting only that component of said protection light exiting said second face of said, liquid crystal layer having a given polarization state in order to form an output image, said system being characterized by improvements permitting it to produce either a simultaneous display of color symbology and achromatic gray scale images or a separate display of either one of them, said improvements residing in: a) means for orienting the polarization direction of said projection light entering said second surface of said liquid crystal layer so that the orthogonal projection of said polarization direction on said plane parallel to either of said surfaces falls within said acute angle between said orientation directions, and; b) means for adjusting the magnitude of said electric field applied across said liquid crystal layer to at least first and second fixed values, said second value being greater than said first value, 1) the first fixed value being such that a writing light input image having first and second intensity ranges, wherein the intensity levels of said second range are greater than the intensity levels of 20 said first range, results in said transmitting means passing: i) a multicolor output image whose colors are a function of said first intensity range, and ii) an achromatic gray scale output image whose intensity range is a function of said second intensity range, 2) the second fixed value of said electric field being such that a writing light input image having a given intensity range results in said transmitting means passing an achromatic gray scale output image whose intensity range is a function of said given intensity range.

Claim 16

A system for displaying an image having: A) an electric field driven liquid crystal light valve of the type having a plurality of adjacent functional layers arranged in the sequential order of; B) a first transparent conductive electrode, a reflective layer, a photoresponsive layer, a first transparent insulating layer, a nematic liquid crystal layer characterized by first and second surfaces, a second transparent insulating layer and a second transparent conductive electrode, %? herein said liquid crystal layer is characterized by a molecular structure such that, in the absence of said electric field, the long axes of the liquid crystal molecules are in spirally twisted alignment with respect to one another, molecules adjacent to said first surface having said axes oriented in a first direction parallel to said first surface, and molecules adjacent to said second surface have said axes oriented in a second direction parallel to said second surface so that said first and second directions intersect at an acute angle when orthogonally projected onto a plane parallel to either of said surfaces; C) means for applying an alternating electric field across said first and second electrodes; D) means for projecting polarized projection light through said second transparent electrode in order to traverse said liquid crystal layer, reflect from said reflecting means, and retraverse said layers; E) means for projecting external writing light images through said first transparent electrode onto said photoresponsive layer, and F) means for transmitting only that component of said protection light exiting said second face of said, liquid crystal layer having a given polarization state in order to form an output image, said system being characterized by improvements permitting it to produce either a simultaneous display of color symbology and achromatic gray scale images or a separate display of either one of them, said improvements residing in: a) means for orienting the polarization direction of said projection light entering said second surface of said liquid crystal layer so that the orthogonal projection of said polarization direction on said plane parallel to either of said surfaces falls within said acute angle between said orientation directions, and; b) means for adjusting the magnitude of said electric field applied across said liquid crystal layer to at least first and second fixed values, said second value being greater than said first value, 1) the first fixed value being such that a writing light input image having first and second intensity ranges, wherein the intensity levels of said second range are greater than the intensity levels of 20 said first range, results in said transmitting means passing: i) a multicolor output image whose colors are a function of said first intensity range, and ii) an achromatic gray scale output image whose intensity range is a function of said second intensity range, 2) the second fixed value of said electric field being such that a writing light input image having a given intensity range results in said transmitting means passing an achromatic gray scale output image whose intensity range is a function of said given intensity range.

Claim 18

A system as in Claims 7, 8 or 9 wherein said acute angle is 45°.

Claim 19

A system as in Claims 7, 8 or 9 wherein said polarized projection light is linearly polarized.