Abstract: A projector (100) including an liquid crystal display image source (120), a field lens (126), and a projection lens (128) projects a full-color image by projecting and converging images of multiple liquid crystal displays ("LCDs"). The image is properly positioned without keystoning by tilting the field lens and offsetting the center of the LCD image source from the optical axis (142) of the projection lens. Trapezoidal error is eliminated by maintaining the optical center (156) of the field lens on the optical axis of the projection lens. During focusing, a mounting apparatus (164) adjusts the offset (154) between the center of the LCD and the optical axis of the projection lens for proper convergence of the images and maintains the optical center of the field lens on the optical axis of the projection lens.

Abstract: A flat panel display that is convertible between direct and projection display applications is incorporated in an information processing device of a unitary construction. In preferred embodiment, the information processing device is selectively configurable as a laptop-style personal computer and a projection display panel. The device includes a base section that contains computer circuitry, supports data input keys, and is pivotally coupled to a display panel section having an addressable flat panel display and an opaque backing member in opposed face-to-face relation thereto. The display panel section is selectively positionable between a first position in which the flat panel display is directly observable by a user, a second position in which the backing member covers the flat panel display and the data input keys for storage purposes, and a third position in which the display panel section is generally nonoverlapping and co-planar with the base section.

Abstract: An LCD display system is formed by stacking two or more independently operated LCD elements. By exploiting the birefringent effect of STN nematic liquid crystals a full range of colors may be displayed. Display rows in the stacked panels are preferably interlaced to achieve high display resolution. Optics are desirably included to collimate light, illuminating the stacked elements, to reduce parallax effects and to disperse light exiting the stacked elements to permit wide angle viewing. The contrast between a pixel in the dark state and in the white state of the high resolution display system may be increased by modifying the .DELTA.nd product of the liquid crystal in the passive regions to compensate for the natural birefringence of the liquid crystal in optically aligned active regions.

Abstract: A color display is formed by stacking two or more birefringent elements that are tuned to provide different spectral characteristics, and operating each of the elements independently.

Abstract: A color display system includes two colored LCD panels operated in conjunction with a colored filter. One of the LCDs may be a primary color, such as red, green or blue, and the other LCD may be its complement, i.e. cyan, magenta or yellow, respectively. The color filter may be in mosaic form and desirably comprises pixels of two subtractive primary colors that are chosen to cooperate with the colored panels to yield a full color display. The invention's use of only two stacked panels and two colored filter elements yields a number of performance and design advantages over prior art full color systems that must rely on three stacked panels or three colored filter elements.

Abstract: A high resolution LDC display is fabricated with a plurality of panels. Each panel has active rows and inactive rows. The panels are stacked and aligned so that each active row is in alignment with inactive rows in all the other panels of the stack. The parallax problem inherent with this stacked cell approach is eliminated by a lens system that collimates light illuminating the stacked assembly.

Abstract: A display system is formed by stacking three birefringent LCD panels that are tuned to different substractive primary colors (i.e. yellow, cyan and magenta). Interposed between the panels, and sandwiched about the stack, are polarizers. At least some of the polarizers are colored to improve the resulting brightness. In some embodiments, the assembly is illuminated by a collimated light source and the resulting image is focused onto a projection screen for viewing. In other embodiments, optics on the front and rear surfaces of the assembly permit direct viewing without parallax effects.

Abstract: A preferred display system is formed by stacking three STN birefringent LCD panels that are tuned to different subtractive primary colors (i.e. yellow, cyan and magenta). Interposed between the panels, and sandwiched about the stack, are polarizers. At least some of the polarizers may be colored to enhance the birefringence color characteristics and to improve brightness. In some embodiments, the assembly is illuminated by a collimated light source and the resulting image is focused onto a projection screen for viewing. In other embodiments, optics are provided to permit direct wide angle viewing of the display without parallax effects.

Abstract: A matrix display drive circuit is disclosed which generates multilevel and multiphase, time-variant drive waveforms for driving the rows and columns of a ferrolectric liquid crystal matrix display. The circuit can provide up (write) and down (erase) pulses selectively to each pixel of the display using standard twisted-nematic type liquid crystal display drivers. A complex waveform generator provides multilevel, multiphase control signals to the supply voltage inputs of the drivers. Timing and synchronizing signals are extracted from the graphics data and timing source outputs to allow such multilevel, multiphase signals as may be required for the effective multiplexing of the display matrix.