Abstract: Single cell gap transflective liquid crystal display which provides that the backlight traverses the reflective pixel portion twice and thereby follows a path similar to that of the ambient light. A slant reflector is built on the path of the back light to reflect the transmitted light to the reflective portion so that the back light and ambient light follow similar paths.

Abstract: Transflective twisted nematic (TN) liquid crystal displays(LCDs) having enhanced transmission efficiencies. Due to the use of circularly polarized light, the novel TN transflective LCD uses a new operation mode between the conventional First and Second Minimums, which alters the retardation value of the reflection and the transmission portions, where the retardation values each include a cell gap spacing. This results in the cell gap spacing in the transmission portion of the transflective LCD to be approximately triple the cell gap spacing in the reflection portion of the transflective LCD whereby the transmission efficiency increases to approximately 90 percent.

Abstract: A high reflection and transmission transflective liquid crystal display (TLCD) that requires only a single cell gap. Instead of reducing the cell gap of the R sub-pixel region, the invention reduces the birefringence change &Dgr;n of reflective pixels(R) so that the total retardation change &Dgr;nd of R is equal to that of the transmissive pixels (T). This is realized by a partial switching of the pixels of approximately 45 degrees which occurs in the reflective pixel(R) region of the single cell gap by applying fringing fields, generated by a discontinuous electrode, to the molecules in the reflective pixel(R) region of the cell gap.

Abstract: A high contrast ratio reflective STN LCD structure including an glass substrate panel, a liquid crystal layer and a lower glass substrate panel. The upper glass substrate panel includes only one optical deflector. The phase compensating film disposed under the optical deflector has a quarter of wavelength. The liquid crystal molecules of the liquid crystal layer have torsion angle within 180° to 210°. The retardation value of the liquid crystal molecules is within 580 nm to 650 nm.

Abstract: A tuneable impedance surface for steering and/or focusing a radio frequency beam. The tunable surface comprises a ground plane; a plurality of elements disposed a distance from the ground plane, the distance being less than a wavelength of the radio frequency beam; and a capacitor arrangement for controllably varying the capacitance of adjacent top plates, the capacitor arrangement including a dielectric material which locally changes its dielectric constant in response to an external stimulus.

Abstract: A high contrast ratio reflective STN LCD structure including an glass substrate panel, a liquid crystal layer and a lower glass substrate panel. The upper glass substrate panel includes only one optical deflector. The phase compensating film disposed under the optical deflector has a quarter of wavelength. The liquid crystal molecules of the liquid crystal layer have torsion angle within 180° to 210°. The retardation value of the liquid crystal molecules is within 580 nm to 650 nm.

Abstract: Specific dopants are provided that protect high birefringence liquid crystals from UV and thermal degradation. These dopants are called “amino-tolane” compounds and have a structure given by: where Rm and Rn are each independently an alkyl group or an alkoxy group having from 1 to 12 carbon atoms or an alkenyl group or an alkenyloxy group having from 2 to 12 carbon atoms, X is selected from the group consisting of NO2, CN, NCS, F, CF3, and OCF3, and Y1 and Y2 are each independently H or F. The advantages of the use of the amino-tolanes are numerous, including the fact that a simple process is used to form them, they are low cost, they maintain high birefringence and large dielectric anisotropy of the liquid crystal, and the viscosity of the mixture of the dopants with the liquid crystal is low.

Abstract: A colorless dopant is provided that has a viscosities approximately the same as that of liquid crystal compositions and supports low voltage operation. The dopants have one of three structures: (1) biphenyl; (2) diphenyl-diacetylene; and (3) double tolane, and in each case, have an amino group (secondary or tertiary) attached at one end of the molecule, with at least one polar group at the other end of the molecule. Schematically, the generic structure may be illustrated as: where R1 is an alkyl having from 1 to 12 carbon atoms, R2 is hydrogen or, independently of R1, an alkyl having from 1 to 12 carbon atoms, M is a polar group, X and Y are independently hydrogen or a polar group not necessarily the same as M, and (A) is (1) a single bond (biphenyl); (2) —C≡C—C≡C— (diphenyl-diacetylene); or (3) (double tolane), where Z is hydrogen, F, or alkyl.

Abstract: A new class of asymmetric polar diphenyldiacetylene liquid crystal compounds and method for preparation are disclosed. The new class of liquid crystal compounds comprises the basic structure: Wherein R1 is an alkenyl group having the general formula (C2H2n−1), X is a cyano group, a fluoro group, CF3, OCF3, or a chloro group, Y1 is unsubstituted, a fluoro group, a chloro group or a methyl group, Y2 is unsubstituted, a fluoro group, a chloro group, or a methyl group, Z1 is unsubstituted, a fluoro group, or a methyl group, and Z2 is unsubstituted, a fluoro group, or a methyl group. The compounds disclosed exhibit high birefringence, low rotational viscosity, and have unexpectedly broad nematic ranges. Also disclosed are eutectic mixtures comprising at least one polar diphenyldiacetylene having the general structure described above. The eutectic mixtures also have unexpectedly broad nematic ranges.

Abstract: An optical display employs a liquid crystal cell with a d.DELTA.n/.lambda. of approximately 0.2-0.8, allowing the cell's optical transmissivity to be modulated by an applied electric field through a dominant non-polarization rotation effect. For visible wavelengths, d.DELTA.n is approximately 0.1-0.4 microns, with a preferred value of about 0.25 microns. Applications include a reflective projection display in which input light is polarized at a greater than 0.degree. and less than 90.degree. angle, preferably about 20.degree., to the input LC directors of a twisted nematic cell; a reflective direct view system in which a quarter-wave plate is substituted for a polarization analyzer; and both a reflective and a transmissive guest-host system in which optical absorption by dye molecules is the dominant modulation mechanism.

Abstract: An optical display employs a liquid crystal cell with a d.DELTA.n/.lambda. of approximately 0.2-0.8, allowing the cell's optical transmissivity to be modulated by an applied electric field through a dominant non-polarization rotation effect. For visible wavelengths, d.DELTA.n is approximately 0.1-0.4 microns, with a preferred value of about 0.25 microns. Applications include a reflective projection display in which input light is polarized at a greater than 0.degree. and less than 90.degree. angle, preferably about 20.degree., to the input LC directors of a twisted nematic cell; a reflective direct view system in which a quarter-wave plate is substituted for a polarization analyzer; and both a reflective and a transmissive guest-host system in which optical absorption by dye molecules is the dominant modulation mechanism.

Abstract: An optical display employs a liquid crystal cell with a d.DELTA.n/.lambda. of approximately 0.2-0.8, allowing the cell's optical transmissivity to be modulated by an applied electric field through a dominant non-polarization rotation effect. For visible wavelengths, d.DELTA.n is approximately 0.1-0.4 microns, with a preferred value of about 0.25 microns. Applications include a reflective projection display in which input light is polarized at a greater than 0.degree. and less than 90.degree. angle, preferably about 20.degree., to the input LC directors of a twisted nematic cell; a reflective direct view system in which a quarter-wave plate is substituted for a polarization analyzer; and both a reflective and a transmissive guest-host system in which optical absorption by dye molecules is the dominant modulation mechanism.

Abstract: An imaging system that can tolerate high intensity optical beams without a reduction in the system's field-of-view, comprises an imager, a fiber array positioned at the image plane of the imager, a sensor array positioned at the output end of the fiber array, a panel display positioned in proximity of the fiber array and an image processor for electronically processing the information from the sensor array.

Abstract: A focal-plane detector imaging system that can tolerate higher intensity optical beams than prior systems, without a reduction in the system's field-of-view, comprises an imaging lens, a fiber optic array positioned at the image plane of the imaging lens and an image detector positioned at the output end of the fiber optic array. The optical fibers that make up the fiber array have core diameters that are larger than the focal spot of an incoming optical beam. In operation, the fiber array transfers the imaged scene to the image detector at its output end. The focused optical beam is also transferred to the image detector at the array's output end, but its diameter is enlarged due to its angular divergence. In a preferred embodiment, the f-number of the imaging lens, diameter of the fiber cores, and the lengths of the fibers in the array are designed so that, as the power of an incoming optical beam increases, the optical damage threshold of the fiber array is reached before that of the image detector.

Abstract: A new class of asymmetrical diphenyl-diacetylene liquid crystal compounds exhibit ideal properties for formulating eutectic mixtures suitable for infrared and microwave applications. The new class of liquid crystal compounds comprise asymmetrical nonpolar end groups. These compounds exhibit low melting points, wide nematic temperature range and low heat fusion enthalpy. Eutectic mixtures containing entirely diphenyl-diacetylene homologs using the new compounds have high birefringence, low viscosity and wide nematic range. These unique properties are especially advantageous when these mixtures are used in infrared spatial light modulators, high speed liquid crystal modulators and polymer dispersed liquid crystals shutters. The new asymmetrical diphenyl-diacetylene liquid crystal compounds comprise the following basic structure:R.sub.1 --C.sub.6 H.sub.4 --C.tbd.C--C.tbd.C--C.sub.6 H.sub.4 --R.sub.2wherein R.sub.1 and R.sub.2 are nonpolar end groups and R.sub.1 does not equal R.sub.2. R.sub.

Abstract: A liquid crystal (LC) display method and apparatus applies respective active LC bias voltages to both a master LC cell, and a phase compensation LC cell for the master cell. The bias voltages are selected to reduce the response time of the master cell, and to establish a common multicolor dark state for that cell. With a proper selection of the bias voltages, the products of the liquid crystal thickness and birefringence for each cell are substantially equal and mutually cancel. A bias voltage is first established for one cell, and the bias voltage for the other cell is then scanned to locate the point of mutual cancellation. A range of different bias voltages are possible, and a suitable bias is selected to balance response time against the required operating voltage range. A multicolor display system using only a single light valve can be realized.

Abstract: An eye protection device 10 comprising a liquid crystal light valve 20 for providing an image of a scene. The light valve images the field of view under observation in a spectral range which matches the human eye. It will automatically reject a laser threat by simply absorbing the energy therefrom in the photoconductive layer thereof. Thus, the invention 10 provides a broad spectrum, zero response time, angle and polarization independent, sensitive eye protection device having a fast recovery time, high extinction coefficient and a high damage threshold. Hence, the invention is expected to be of significant utility to personnel operating in hostile environments.

Abstract: A spatial light modulator includes a photosensor diode and a photoemitting diode array, each having two semiconductive layers of opposite electrical polarities, and which are sandwiched together with layers of the same polarity (P or N) in electrical contact with each other. Transparent electrode layers are formed on the opposite surfaces of the photosensor diode and photoemitting diode array respectively, in electrical contact with the layers of the opposite polarity. The individual photoemitting diodes are electrically and optically isolated from each other. With a voltage applied across the electrodes which causes the photosensor diode to be reverse biased and the photoemitting diodes to be forward biased, the photoemitting diode array generates a visual display which is a reproduction of a light image incident on the photosensor diode. The photosensor diode may be replaced by a single layer of a photoconductive material.

Abstract: A broad-band optical light detector having a detector cell, a system for focusing light on the cell, and a liquid crystal positioned in the light path, the liquid crystal being prepared so that it passes light along the light path in the normal operating range of the detector cell and directs light away from the light path when a threshold intensity of light is reached.

Abstract: A light detector (10) comprising a detector cell (12); a system for focusing light (14, 16, 18) on the cell; a liquid crystal (22) positioned in the light path; the liquid crystal (22) being prepared so that it passes light along the light path in the normal operating range of the detector cell (12) and directs light away from the light path when a threshold intensity of light is reached; and source of bias (24) across the crystal to enhance the recovery of the crystal (22).