Abstract: An LCD projection unit employs a luminance and color balance system employing an LCD array characterization lookup table storing multiple sets of luminance and gamma correction values that are user selectable to control luminance and color balance. The lookup table values are determined by measuring the transfer function of the LCD array in the projection unit for each of a set of red (“R”), green (“G”), and blue (“B”) input data values, converting the resulting S-curve responses to corresponding sets of gamma responses and scaling the gamma responses to generate multiple R, G, and B families of luminance and gamma corrected values. Color balance is adjusted by selecting the particular R, G, and B families of luminance and gamma corrected values that cause the LCD projection unit to match a predetermined ratio of R, G, and B luminance values.

Abstract: A liquid crystal display ("LCD") projection unit (12) employs a luminance and color balance system having a lookup table (100) storing multiple sets of gain and/or gamma corrected responses (92-99) for color balance and luminance control. The lookup table values are determined by measuring an S-curve response (90) of an LCD array (40) for each of a set of R, G, and B input data values, converting the S-curve responses to a corresponding set of gamma responses, and scaling the gamma responses to generate red ("R"), green ("G"), and blue ("B") families of gain and gamma corrected values. Color balance is adjusted by selecting the particular R, G, and B families of gain and gamma corrected values that cause the LCD projection unit to match a predetermined ratio of maximum R, G, and B luminance values. Luminance is adjusted by selecting families of lookup table values that adjust the transmittance of the LCD while maintaining the color balance.

Abstract: A mechanical package for an LCD projector includes approximately equally sized tower and enclosure portions. The tower portion is supported on forward protruding legs and contains optical and electronic modules that slide into its rear and are also accessible from the front of the enclosure portion. The enclosure portion supports on its front a removable projection screen and is mounted vertically offset on the tower portion. A triply folded optical axis provides a suitably long light pathway for projecting a large image on the projection screen without requiring the package to have an undue depth. To stack multiple packages vertically, side margins of the tower portion top surface include L-channels that receive the legs of a package stacked above. The enclosure portion further includes openings that receive the legs protruding from the tower portion stacked above. The legs are supported within the enclosure portion by sliding into U-brackets that are attached to the inner surfaces of the enclosure portion.

Abstract: A projection display (12) employs a fiber optic homogenizer (32) that includes a bundle (60) of optical fibers arranged such that an input end (64) has a substantially round cross-sectional shape that receives nonuniform illumination generated by a projection light source (24,26). The fiber optic homogenizer contains optical fibers that are interwoven and rerouted through the length of the bundle to terminate in an output end (66) having the same shape as a light valve (40) that generates the image projected by the display. The interweaving and rerouting provides a substantially random redistribution of fibers across the shape of the output end to propagate a uniform, rectangular illumination beam onto the light valve with very little light loss.

Abstract: An electronic transparency device is provided with a memory in which a plurality of frames of video data ("slides") can be stored. The apparatus includes a control microprocessor which can cause predefined sequences of slides to be presented on the LCD panel automatically. These slide "shows" are defined by the user using a hand held remote control unit in conjuntion with menus displayed on the LCD panel in window fashion by the microprocessor. The user can specify the duration that each slide in a sequence is to be shown, the video transition by which it is to be introduced, the degree of "windowshading" with which it is to be displayed, etc. Once a show is defined, it can be instituted and controlled from the remote control unit. Among other numerous features, the transparency also includes a pointer that can be superimposed on the display and controlled by the remote control unit. This pointer can be used to define certain portions of the screen that are to be displayed in highlighted fashion.

Abstract: An electronic transparency device is provided with a memory in which a plurality of frames of video data ("slides") can be stored. The apparatus includes a control microprocessor which can cause predefined sequences of slides to be presented on the LCD panel automatically. These slide "shows" are defined by the user using a hand held remote control unit in conjuntion with menus displayed on the LCD panel in window fashion by the microprocessor. The user can specify the duration that each slide in a sequence is to be shown, the video transition by which it is to be introduced, the degree of "windowshading" with which it is to be displayed, etc. Once a show is defined, it can be instituted and controlled from the remote control unit. Among other numerous features, the transparency also includes a pointer that can be superimposed on the display and controlled by the remote control unit. This pointer can be used to define certain portions of the screen that are to be displayed in highlighted fashion.

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: The present invention includes a case (54) for an overhead projection display panel (50) used with an overhead projector light source (52). The case supports a light modulating element (60) such as, for example, a liquid crystal device, and encases modulation control circuitry (32) for controlling the light modulating element. The case includes an annular case element (56) for supporting the light modulating element along its side margin so that it can modulate light transmitted from the overhead projector light source. The case also includes an occluding panel (58) connected to and extendable from the annular case element for selectably occluding a portion of the overhead projector light source. At least one of the annular case elements and the occluding panel encasing the modulation control circuitry of the display panel.

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: An electronic transparency device is provided with a memory in which a plurality of frames of video data ("slides") can be stored. The apparatus includes a control microprocessor which can cause predefined sequences of slides to be presented on the LCD panel automatically. These slide "shows" are defined by the user using a hand held remote control unit in conjuntion with menus displayed on the LCD panel in window fashion by the microprocessor. The user can specify the duration that each slide in a sequence is to be shown, the video transition by which it is to be introduced, the degree of "windowshading" with which it is to be displayed, etc. Once a show is defined, it can be instituted and controlled from the remote control unit. Among other numerous features, the transparency also includes a pointer that can be superimposed on the display and controlled by the remote control unit. This pointer can be used to define certain portions of the screen that are to be displayed in highlighted fashion.

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 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 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 TFEL panel includes orthogonally disposed sets of scanning and data electrodes. The scanning electrodes are strobed with a preconditioning voltage and data is provided to selected data electrodes simultaneously with the line by line strobing of the scanning electrodes. A refresh pulse is applied to the screen once per frame of data at times which vary from frame to frame. This may be accomplished either by varying the time of occurrence of the refresh pulse within each frame or by holding the time of occurrence of the refresh pulse constant and varying the strobing sequence of the scanning electrodes. This technique prevents certain portions of the screen from generating a latent image due to charge accumulation which would otherwise result from the timing asymmetry between the scanning of certain electrodes and the fixed timing of the refresh pulse.

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.