Xerox Corporation

John B Flannery

Joel M Pollack

Andras I Lakatos

Anita C Van Laeken

An imaging method which is comprised of a spatially varying imagewise output intensity for a corresponding imaging input. An imaging member comprising between two electrodes a photoconductor in contact with an about 1 to about 6 micron thick layer of nematic liquid crystalline material, which in the absence of an electrical field is in the homogeneous texture, and having negative dielectric anisotropy is utilized. A d.c. voltage above the parallel variable grating mode threshold for the nematic liquid crystalline material is applied between the two electrodes of the imaging member and, while the voltage is applied, the photoconductor is exposed to imagewise configured actinic electromagnetic radiation from a first radiation source. The actinic radiation causes the voltage to increase across portions of the nematic liquid crystalline layer in electrical contact with regions of the photoconductor exposed to the actinic radiation. The increase in voltage across these portions of the liquid crystalline material is sufficient to cause cylindrical, vortical domains of molecules of the nematic liquid crystalline material to form with their long axes parallel to the initial direction of homogeneous alignment (a parallel variable grating mode). The spatial frequency of the vortical domains varies dynamically with the intensity of the actinic electromagnetic radiation. From a second radiation source, electromagnetic radiation which is non-actinic to the photoconductor by virtue of either the photoconductor or imaging member structure, is modified by the imagewise configured liquid crystalline texture resulting in a projection image of second source radiation corresponding to the imagewise configured first source electromagnetic radiation.

Imaging method

Bistable deflection of a beam of light into and out from a layer of nematic liquid crystalline material having negative dielectric anisotropy and having a thickness of from about 1 micron to about 6 microns is achieved by providing the nematic liquid crystalline material in the parallel variable grating mode between two electrodes, the nematic being under an applied voltage between the two electrodes at a voltage level above the threshold voltage level for parallel variable diffraction mode for said nematic liquid crystalline material, and increasing and decreasing the applied voltage so that light diffracted by the parallel variable grating mode nematic is deflected at an angle which either exceeds or is less than the critical angle between the layer of nematic liquid crystalline material and one of the electrodes. When the deflection of diffracted light is increased in excess of the critical angle, the incident light is totally reflected within the nematic layer; and, when the deflection angle of the diffracted light is decreased below the critical angle, the incident light is diffracted through the nematic layer and the one electrode. The bistable deflection can be utilized in a reproduction device which converts a data chain of electrical signals into an image and in integrated optics.

Bistable deflection system

Disclosed are novel imaging imaging comprising photochromic compounds of the formula: ##SPC1## Wherein X is selected from the group consisting of oxygen, sulfur and selenium; and wherein R.sub.1 and R.sub.2 are individually selected from the group consisting of a substituted or unsubstituted lower alkyl of 1-8 carbon atoms or a substituted or unsubstituted phenyl group. The photochromic compounds are responsive to light in the visible and ultraviolet region of the spectrum.

Photochromic composition containing a diphenyl dibenzochrom-3-ene

There is disclosed an imaging system for forming a plurality of images on the same surface. The imaging system includes an electro-optic imaging member comprising a voltage or current-sensitive light modulating layer, a layer of photoconductive material which exhibits persistent photoconduction properties and a layer of material capable of generating photoinjection currents when struck by radiation which it absorbs.

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Webster, NY, United States of America

John B Flannery