Abstract: A liquid crystal display device includes a substrate, a liquid crystal layer, a liquid crystal alignment layer between the substrate and the liquid crystal layer, a barrier layer between the liquid crystal alignment layer and the liquid crystal layer, and a gasket formed around the perimeter of the liquid crystal layer and abutting the barrier layer. The gasket has a width less than or equal to 400 micrometers. A second substrate also includes a liquid crystal alignment layer and a barrier layer formed over the liquid crystal alignment layer. The gasket also abuts the barrier layer of the second substrate. In a particular embodiment, the substrate is a reflective display backplane, and the second substrate is a transparent substrate having a transparent electrode layer. The gasket of the present invention is much narrower than gaskets of the prior art, which enables LCD devices to be made smaller and cheaper because more LCD devices can be produced per wafer.

Abstract: A method for synchronizing a light source control signal with modulation of a display includes the steps of receiving a video signal including a synchronization signal (e.g., a Vsync signal) and using the synchronization signal to generate a light source control signals at high and low values. The light source control signal is pulsed between its high and low values between subsequent synchronization signals to cause a light source to produce light pulses at the same time over each frame of the display. Optionally, the low and/or high time periods are adjustable. A novel display driver is also disclosed and includes an input terminal for receiving the synchronization signal, a light source driver for generating the light source control signal in response to the synchronization signal, and an output terminal for providing the light source control signal to a light source control unit.

Abstract: An electro-optical projection system includes a polarizer, a reflective light modulator, an analyzer, and a compensation element. The polarizer polarizes an illumination beam to form a polarized illumination beam. The reflective light modulator receives the polarized illumination beam along a first optical path, modulates the polarized illumination beam to form an imaging beam, and reflects the imaging beam along a second optical path. The compensation element is disposed in the polarized illumination beam and the imaging beam to compensate for polarization aberrations resulting from the birefringent property of the material of the reflective light modulator. The compensation plate has a retardation generally equal in magnitude and opposite in sign as compared to the retardation of the liquid crystal material of the reflective light modulator.

Abstract: A method for synchronizing a light source control signal with modulation of a display includes the steps of receiving a video signal including a synchronization signal (e.g., a Vsync signal) and using the synchronization signal to generate a light source control signals at high and low values. The light source control signal is pulsed between its high and low values between subsequent synchronization signals to cause a light source to produce light pulses at the same time over each frame of the display. Optionally, the low and/or high time periods are adjustable. A novel display driver is also disclosed and includes an input terminal for receiving the synchronization signal, a light source driver for generating the light source control signal in response to the synchronization signal, and an output terminal for providing the light source control signal to a light source control unit.

Abstract: An electro-optical projection system includes a polarizer, a reflective light modulator, an analyzer, and a compensation element. The polarizer polarizes an illumination beam to form a polarized illumination beam. The reflective light modulator receives the polarized illumination beam along a first optical path, modulates the polarized illumination beam to form an imaging beam, and reflects the imaging beam along a second optical path. The compensation element is disposed in the polarized illumination beam and the imaging beam to compensate for polarization aberrations resulting from the birefringent property of the material of the reflective light modulator. The compensation plate has a retardation generally equal in magnitude and opposite in sign as compared to the retardation of the liquid crystal material of the reflective light modulator.

Abstract: A system and method for reducing the intensity output response time of a liquid crystal display is disclosed. A display driver circuit selectively substitutes compensation data words for data words in a data stream, in order to reduce the intensity output rise time of a liquid crystal display. In one embodiment, the display driver circuit includes a buffer and a rise time compensator. The buffer receives and stores a first data word intended to be written to a particular pixel. The rise time compensator, upon receipt of a second data word intended for the same pixel, retrieves the first data word from the buffer, compares the value of the second data word to the value of the first data word, and selectively outputs either the second data word or a compensation data word, depending on the relative values of the first and second data words.

Abstract: A novel projection system includes an illumination source for emitting an illumination beam, a reflective display device for modulating the illumination beam to form a reflected imaging beam, a projection lens group having an optical axis, and a field lens group. The field lens group is de-centered with respect to the optical axis of the projection lens group and is disposed to redirect the illumination beam to illuminate the display device at a non-zero angle of incidence, and to redirect the reflected imaging beam along an optical path parallel to the optical path of the projection lens group. In a particular embodiment the display device is disposed on the optical axis of the projection lens group. In a more particular embodiment, the redirected portion of the optical path of the reflected imaging beam is coincident with the optical axis of the projection lens group.

Abstract: The mechanism of and a solution to the problem of vertical banding in projection systems is disclosed. An offset lens array includes a plurality of lens elements arranged in a plurality of rows that are offset with respect to one another. The offset lens array is incorporated in an illuminator for a projection system. The asymmetrical arrangement of the rows of lens elements in the array with respect to a seam in a color separation element of the projection system substantially reduces the vertical banding in the projected image.

Abstract: A system and method for reducing the intensity output response time of a liquid crystal display is disclosed. A display driver circuit selectively substitutes compensation data words for data words in a data stream, in order to reduce the intensity output rise time of a liquid crystal display. In one embodiment, the display driver circuit includes a buffer and a rise time compensator. The buffer receives and stores a first data word intended to be written to a particular pixel. The rise time compensator, upon receipt of a second data word intended for the same pixel, retrieves the first data word from the buffer, compares the value of the second data word to the value of the first data word, and selectively outputs either the second data word or a compensation data word, depending on the relative values of the first and second data words.

Abstract: An off-axis projection system includes a polarizer, a reflective light modulator, an analyzer, and an aberration compensation element. The polarizer polarizes an illumination beam to form a polarized illumination beam. The reflective light modulator receives the polarized illumination beam along a first optical path, modulates the polarized illumination beam to form an imaging beam, and reflects the imaging beam along a second optical path not parallel to the first optical path. The aberration compensation element is disposed in either or both of the polarized illumination beam and the imaging beam. The separation of the illumination beam and the imaging beam provided by the off-axis architecture facilitates the use single-pass aberration compensation elements, including liquid crystal compensation films and wave retarders. A multi-color projection system is also disclosed.

Abstract: An off-axis projection system includes a polarizer, a reflective light modulator, an analyzer, and an aberration compensation element. The polarizer polarizes an illumination beam to form a polarized illumination beam. The reflective light modulator receives the polarized illumination beam along a first optical path, modulates the polarized illumination beam to form an imaging beam, and reflects the imaging beam along a second optical path not parallel to the first optical path. The aberration compensation element is disposed in either or both of the polarized illumination beam and the imaging beam. The separation of the illumination beam and the imaging beam provided by the off-axis architecture facilitates the use single-pass aberration compensation elements, including liquid crystal compensation films and wave retarders. A multi-color projection system is also disclosed.

Abstract: The mechanism of and a solution to the problem of vertical banding in projection systems is disclosed. An offset lens array includes a plurality of lens elements arranged in a plurality of rows that are offset with respect to one another. The offset lens array is incorporated in an illuminator for a projection system. The asymmetrical arrangement of the rows of lens elements in the array with respect to a seam in a color separation element of the projection system substantially reduces the vertical banding in the projected image.

Abstract: A novel projection system includes an illumination source for emitting an illumination beam, a reflective display device for modulating the illumination beam to form a reflected imaging beam, a projection lens group having an optical axis, and a field lens group. The field lens group is de-centered with respect to the optical axis of the projection lens group and is disposed to redirect the illumination beam to illuminate the display device at a non-zero angle of incidence, and to redirect the reflected imaging beam along an optical path parallel to the optical path of the projection lens group. In a particular embodiment the display device is disposed on the optical axis of the projection lens group. In a more particular embodiment, the redirected portion of the optical path of the reflected imaging beam is coincident with the optical axis of the projection lens group.

Abstract: A projection system includes a collimating lens group for collimating an imaging beam. The collimating lens group has an optical axis that is de-centered with respect to the axis of the imaging beam. Further, the optical axis of the collimating lens group forms a non-zero angle with the axis of the imaging beam. The de-centered collimating lens group enables the use of more conventional projection optics, without the unacceptable displacement of the projected image.

Abstract: A method is disclosed for addressing a matrix-array type liquid crystal layer. The cell has a plurality of pixels which are defined by regions of overlap between two sets of electrodes which sandwich a liquid crystal layer, each pixel having two states. The response time for switching between the two states is dependent upon the voltage across the liquid crystal layer, with a minimum occurring at a particular voltage. The method includes applying a strobe waveform to a selected member of a first set of the electrodes while a data waveform is applied to each member of the second set of electrodes. A waveform for switching a pixel defined by the selected member comprises a switching pulse of a given voltage magnitude and given duration. A waveform for not switching a pixel defined by the selected member comprises a non-switching pulse of a voltage magnitude greater than the given voltage magnitude of the switching pulse and a duration less than the given duration of the switching pulse.

Abstract: A ferroelectric liquid crystal cell is provided with one alignment layer (14) constituted by rubbed nylon which promotes planar alignment in a specific azimuthal direction and the other alignment layer (15) constituted by a polymer with flexible side chains which promotes planar alignment without any preferred azimuthal direction.

Abstract: Bistable switching between clear and scattering states is provided by a liquid crystal cell whose liquid crystal layer is constituted by a random orientation planar aligned ferroelectric smectic exhibiting a pitch length comparable with the wavelength of visible light.

Abstract: Bistable operation of ferroelectric liquid crystal smectic I* or smectic F* display cells is disclosed which uses a greater liquid crystal layer thickness than is achievable with smectic C* material while yet retaining bistability of operation.

Abstract: Novel derivatives of cyclic and acyclic terpenoid alcohols, having general formula (I) X--(CO).sub.n --O--T.sub.1, where n=O or l, T.sub.1 is a terpenoid group and X is a combination of cyclic groups, e.g. phenyl, cyclohexyl and pyrimidyl, X preferably contains up to three cyclic groups. Preferred derivatives are esters of cyclic terpenoid alcohols, e.g. menthol, borneol and isopineocampheol, e.g. formula (II) (-)-menthol. Ferroelectric smectic liquid crystal mixtures and devices containing these derivatives as chiral dopants in a tilted smectic host are also described. The properties of various other derivatives of terpenoid alcohols of formula (I) are also described, e.g. those of neomenthol, isolongifolol, fenchol, carveol, myrthenol, nopol, citronellol, perilla alcohol and dihydrocitronellol.