Abstract: A polarization modulator for time-multiplexed stereoscopic 3D applications rapidly switches between two polarization states in alternate subframes. The polarization modulator uses two liquid crystal devices arranged in optical series and driven such that the second device compensates a change the first device makes to an input polarization state of incident light during alternate subframes. The compensating liquid crystal devices are characterized in that, if the same voltage is applied to both of them, the second device compensates the change that the first device makes to the input polarization state, regardless of the applied voltage level. If the applied voltage is changed from one level to another and the liquid crystal material in the liquid crystal devices relaxes to the new voltage level, polarization state compensation will take place throughout the duration of the relaxation so that the slow, unpowered transition does not manifest itself as a change in polarization state.

Abstract: A polarization modulator for time-multiplexed stereoscopic 3D applications rapidly switches between two polarization states in alternate subframes. The polarization modulator uses two liquid crystal devices arranged in optical series and driven such that the second device compensates a change the first device makes to an input polarization state of incident light during alternate subframes. The compensating liquid crystal devices are characterized in that, if the same voltage is applied to both of them, the second device compensates the change that the first device makes to the input polarization state, regardless of the applied voltage level. If the applied voltage is changed from one level to another and the liquid crystal material in the liquid crystal devices relaxes to the new voltage level, polarization state compensation will take place throughout the duration of the relaxation so that the slow, unpowered transition does not manifest itself as a change in polarization state.

Abstract: Self-compensating, quasi-homeotropic liquid crystal devices overcome the contrast reducing effects of smaller pretilt angles. The devices exhibit extremely high contrast ratio but at the same time suppress fringe field-induced disclination lines in high pixel density and small pixel size quasi-homeotropic displays. The surface pretilt and cell twist angles are set at values that, in combination, contribute to establishing a cuspate singularity in the contrast ratio for normally incident light in response to a drive signal switching the liquid crystal device to the OFF director field state that provides nearly 0% optical efficiency. The OFF director field state corresponds to a subthreshold drive level that provides for the liquid crystal device self-compensation for in-plane optical retardation.

Abstract: Self-compensating, quasi-homeotropic liquid crystal devices overcome the contrast reducing effects of smaller pretilt angles. The devices exhibit extremely high contrast ratio but at the same time suppress fringe field-induced disclination lines in high pixel density and small pixel size quasi-homeotropic displays. The surface pretilt and cell twist angles are set at values that, in combination, contribute to establishing a cuspate singularity in the contrast ratio for normally incident light in response to a drive signal switching the liquid crystal device to the OFF director field state that provides nearly 0% optical efficiency. The OFF director field state corresponds to a subthreshold drive level that provides for the liquid crystal device self-compensation for in-plane optical retardation.

Abstract: A polarization modulator for time-multiplexed stereoscopic 3D applications rapidly switches between two polarization states in alternate subframes. The polarization modulator uses two liquid crystal devices arranged in optical series and driven such that the second device compensates a change the first device makes to an input polarization state of incident light during alternate subframes. The compensating liquid crystal devices are characterized in that, if the same voltage is applied to both of them, the second device compensates the change that the first device makes to the input polarization state, regardless of the applied voltage level. If the applied voltage is changed from one level to another and the liquid crystal material in the liquid crystal devices relaxes to the new voltage level, polarization state compensation will take place throughout the duration of the relaxation so that the slow, unpowered transition does not manifest itself as a change in polarization state.

Abstract: An optically addressed, photoconductive spatial light modulator (SLM) operates in a transmissive mode and is capable of modulating a wide spectrum of visible light. There is no pixel structure or native pixel resolution in the SLM. The SLM has no photodiodes and does not rectify. A light projection system (100) in which one or more SLMs (128, 130, 132) are placed includes a write (image definition) UV light path (102) and a read (illumination) visible light path (104) to form a color image projection display. The write UV light propagates from an image display pattern source (120) and either sequentially or continuously writes image patterns on the photoconductive SLMs. The read visible light propagates through the SLM and is modulated by an electro-optical material, the optical properties of which change in response to the image structure carried by the write light. The result is a high efficiency display system that delivers high resolution color images through a projection lens (190) onto a display screen.

Abstract: Self-compensating, quasi-homeotropic liquid crystal devices (100, 200, 300, 400) overcome the contrast reducing effects of smaller pretilt angles. The devices exhibit extremely high contrast ratio but at the same time suppress fringe field-induced disclination lines in high pixel density and small pixel size quasi-homeotropic displays. The surface pretilt (520, 540) and cell twist (570) angles are set at values that, in combination, contribute to establishing a cuspate singularity in the contrast ratio for normally incident light in response to a drive signal switching the liquid crystal device to the OFF director field state that provides nearly 0% optical efficiency. The OFF director field state corresponds to a subthreshold drive level that provides for the liquid crystal device self-compensation for in plane optical retardation.

Abstract: Self-compensating, quasi-homeotropic liquid crystal devices (100, 200, 300, 400) overcome the contrast reducing effects of smaller pretilt angles. The devices exhibit extremely high contrast ratio but at the same time suppress fringe field-induced disclination lines in high pixel density and small pixel size quasi-homeotropic displays. The surface pretilt (520, 540) and cell twist (570) angles are set at values that, in combination, contribute to establishing a cuspate singularity in the contrast ratio for normally incident light in response to a drive signal switching the liquid crystal device to the OFF director field state that provides nearly 0% optical efficiency. The OFF director field state corresponds to a subthreshold drive level that provides for the liquid crystal device self-compensation for in plane optical retardation.

Abstract: The methods and apparatuses of the invention relate to liquid crystal displays. In one exemplary embodiment, a liquid crystal display includes a liquid crystal layer which has a twist angle in a range of about 60° to about 90° and includes a polarizer positioned to polarize light from a light source to create polarized light such that an angle &bgr; exists between a vector of the polarized light and a first alignment direction of the liquid crystal layer. The angle &bgr; is in a range of about −13° to about +13° and a value of &Dgr;nd is in a range of about 0.1 &mgr;m to about 0.2 &mgr;m where &Dgr;n is a birefringence of the liquid crystal layer and d is a thickness of the liquid crystal layer. Other features of the invention will be apparent from the accompanying drawings and description.

Abstract: Method and apparatus for providing gray level addressing for passive liquid crystal display (LCD) panels having overlapping row and column electrodes defining pixels are disclosed. Depending upon whether the rows are being addressed by "standard" or "Swift" addressing, the signals for applying to the column electrodes are determined by different calculations, in all of which modes the amplitudes of the column signals are related to the gray level desired to be displayed by the individual pixels. For a split interval system, column signals of appropriate amplitude and polarity are applied during different subintervals of a characteristic time interval of the display panel depending upon the method of addressing the rows. In the full interval mode, the column signals applied over a full time interval are based on the desired gray level of all the pixels in the column, adjusted to provide the proper rms voltage across all the pixels so that they display the desired gray levels.

Abstract: An addressing method and apparatus addresses faster responding liquid crystal display panels (LCDs) so that video rate, high information content LCDs having time constants on the order of 50 ms or less are perceived as having improved contrast by limiting peak voltage levels across the pixels. In a preferred embodiment, a first set of LCD electrodes is continuously driven with signals each comprising a train of pulses that are periodic in time, have a common period T, are independent of the information to be displayed, and are preferably orthonormal. Plural column signals are generated from the collective information states of the pixels defined by the overlap with a second electrode pattern. Each column signal is proportional to the sum, obtained by considering each pixel in the column, of the exclusive-or (XOR) products of the logic level of the amplitude of each row signal times the logic level of the information state of the pixel corresponding to that row.

Abstract: Method and apparatus for providing gray level addressing for passive liquid crystal display (LCD) panels having overlapping row and column electrodes defining pixels are disclosed. Depending upon whether the rows are being addressed by "standard" or "Swift" addressing, the signals for applying to the column electrodes are determined by different calculations, in all of which modes the amplitudes of the column signals are related to the gray level desired to be displayed by the individual pixels. For a split interval system, column signals of appropriate amplitude and polarity are applied during different subintervals of a characteristic time interval of the display panel depending upon the method of addressing the rows. In the full interval mode, the column signals applied over a full time interval are based on the desired gray level of all the pixels in the column, adjusted to provide the proper rms voltage across all the pixels so that they display the desired gray levels.

Abstract: Method and apparatus are disclosed for providing gray level addressing for passive matrix liquid crystal display (LCD) panels having pixels defined by overlapping row and column electrodes. The pixels have optical states determined by the rms voltage appearing across the pixels during a frame period. The frame period is divided into characteristic time intervals, which are further divided into sub-intervals. The amplitude of the column signals during each of the sub-intervals is determined from the desired gray level of the pixel or pixels defined by the corresponding column electrode and selected one or ones of the row electrodes.

Abstract: Different gray shades or hues may be displayed in accordance with an active addressing technique that addresses faster responding passive matrix liquid crystal display panels (LCDs) so that video rate, high information content LCDs are perceived as having improved contrast by limiting peak voltage levels across the pixels. A preferred embodiment of the active addressing technique is implemented such that a first set of LCD electrodes is continuously driven with signals each comprising a train of pulses that are periodic in time, have a common period T, are independent of the information to be displayed, and are preferably orthonormal. Multiple column signals are generated from the collective information states of the pixels defined by the overlap with a second electrode pattern.

Abstract: An optical notch filter component in a color LCD display comprises an electronically controllable variable retarder interposed between circularly polarizing elements. Entering light in a particular spectral region is circularly polarized by a first of the circularly polarizing elements, and selectively retarded by zero or a half wavelength by the retarder so as to controllably yield right or left handed circular polarization. The second circular polarizer transmits only one of the circular polarizations of the light. By controlling the circular polarization of the light with the retarder, the light is either transmitted or attenuated. More uniform stopband attenuation is provided when the optical notch filter component comprises oppositely handed circular polarizing elements and a variable retarder which applies zero retardation in one of its states.

Abstract: Integrated driver circuitry including row and column signal generators addresses faster responding liquid crystal display panels (LCDs) so that video rate, high information content LCDs having time constants on the order of 50 ms or less are perceived as having improved contrast by limiting peak voltage levels across the pixels. In a preferred embodiment, a row signal generator includes a row signal function generator and row driver circuitry including a level shifter that delivers to each of the row electrodes a signal level corresponding to the row signal value at a time interval of a frame period. A column signal generator applies to each of the column electrodes a column signal having an amplitude that is determined by the row signals causing selections at a particular time interval and by pixel input data components of corresponding pixels defined by the overlap of the row and column electrodes.

Abstract: A method and an apparatus for addressing a liquid crystal display (10) groups together row electrodes (28) and applies the same row addressing signal to all row electrodes in the group (48). The groupings are cyclically changed in successive addressing cycles. An image data conditioner (54) determines for use in calculating the column signals a pixel information value based upon the information values of one or more of the pixels in the selected group of row. Grouping the row electrodes reduces the effective multiplex ratio, thereby increasing the selection ratio and producing a faster responding display having higher contrast and a wider viewing angle.

Abstract: An addressing method and apparatus addresses faster responding liquid crystal display panels (LCDs) so that video rate, high information content LCDs having time constants on the order of 50 ms or less are perceived as having improved contrast by limiting peak voltage levels across the pixels. In a preferred embodiment, a first set of LCD electrodes is continuously driven with signals each comprising a train of pulses that are periodic in time, have a common period T, are independent of the information to be displayed, and are preferably orthonormal. Plural column signals are generated from the collective information states of the pixels defined by the overlap with a second electrode pattern. Each column signal is proportional to the sum, obtained by considering each pixel in the column, of the exclusive-or (XOR) products of the logic level of the amplitude of each row signal times the logic level of the information state of the pixel corresponding to that row.

Abstract: The optical response of the pixels of many flat panel display devices, such as liquid crystal displays (2), depends upon the spectral components, as well as the rms value, of the pixel voltage waveform during a frame period. Because each row and column electrode (10 and 11) addresses multiple pixels (14), the spectral voltage components of the voltage across any pixel during a frame period will depend upon the optical state of other pixels in the same column (11). This crosstalk phenomena can be greatly reduced by modifying the addressing signals. One method of modifying the addressing signals is to modulate them so that the spectral components of all pixel voltage waveforms fall primarily in a frequency band (54) in which the optical response is nearly independent of the frequency.

Abstract: Method and apparatus for providing gray level addressing for passive liquid crystal display (LCD) panels having overlapping row and column electrodes defining pixels are disclosed. Depending upon whether the rows are being addressed by "standard" or "Swift" addressing, the signals for applying to the column electrodes are determined by different calculations, in all of which modes the amplitudes of the column signals are related to the gray level desired to be displayed by the individual pixels. For a split interval system, column signals of appropriate amplitude and polarity are applied during different subintervals of a characteristic time interval of the display panel depending upon the method of addressing the rows. In the full interval mode, the column signals applied over a full time interval are based on the desired gray level of all the pixels in the column, adjusted to provide the proper rms voltage across all the pixels so that they display the desired gray levels.