Infocus Systems, Inc.

Clarity Visual Systems, Inc.

Paul E Gulick

Arlie R Conner

Steven R Hix

Benjamin R Clifton

John P Fogarty

Robert E Haas

Sohrab Vossoughi

Christopher A Alviar

Jonathon R Biles

Greg A Sorenson

Bruce Sandmeyer

David B Kubeja

Ultra-thin projection system for use in professional and signage applications

Color gamut and luminance matching techniques for image display systems

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. The LCD projection unit achieves a uniform luminance and color balance that renders it suitable for use in a multiscreen display system (10).

Color and luminance control system for liquid crystal projection displays

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. Fasteners are passed through aligned holes in the legs and U-brackets to secure the vertically stacked packages. To stack multiple packages horizontally, the same fasteners that pass through aligned holes in the legs and U-brackets of the vertically stacked packages are also passed through the corresponding aligned holes in the legs and U-brackets of horizontally adjacent packages.

Stairstep interlock mounting package for multiscreen projection displays

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. A multiscreen projection display (70) further matches the luminance and color of adjacent projection displays (86) by employing a single projection light source (24,26) and a fiber optic homogenizer (72) that has an input end shaped and arranged as before, but with a bundle (74) further subdivided into subbundles (76) each terminating in an output end (78) having a shape matched to a light valve (80) in an associated one of the projection displays. The optical fibers are interwoven and routed to provide a subdivision and random redistribution of the fibers across the rectangular cross-sectional shape of each of the output ends.

Fiber optic light homogenizer for use in projection displays

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.

Electronic transparency method and apparatus

Electronic transparency with data storage medium

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.

Convertible flat panel display system

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.

Case for overhead projection display panel

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.

LCD system having improved contrast ratio

Electronic data display panel for use with an overhead projector

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.

Color display using supertwisted nematic liquid crystal material

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.

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Tualatin, OR, United States of America

Paul E Gulick