Clarity Visual Systems, Inc.

Microsoft Technology Licensing, LLC

John P Fogarty

Benjamin R Clifton

Paul E Gulick

Kari Jussi Ropo

Nobuyuki Suzuki

Greg A Sorenson

Aaron Gilbert Moo

David B Kubeja

A backlight control system is provided. A modulation value register is included in memory of the system. A display backlight is included in the system, the display backlight including a light emitting diode (LED) light source configured to illuminate a liquid crystal display (LCD). Processing circuitry included in the system is configured to execute a clock timer and a temporal dither pattern generator. The temporal dither pattern generator is configured to receive a modulation value from the modulation value register, and apply a temporal dither according to a signal from the clock timer to the modulation value to generate a dithered modulation value. A modulator executed by the processing circuitry is configured to receive the dithered modulation value and modulate a power signal according to the dithered modulation value to drive the display backlight.

LCD display backlight control system

Embodiments of collaborative presentation systems are provided. An example collaborative presentation system includes a display device, an image sensor, a network interface, a logic device, and a storage device holding instructions executable by the logic device to retrieve a presentation file that is executed to display a presentation on the display device, receive image frames from the image sensor, the image frames including the display device, the displayed presentation, and a presenter, and extract the presenter from the image frames to generate an extracted presenter image. The instructions are further executable to adjust an appearance of the extracted presenter image to form an adjusted presenter image, generate an updated presentation file, the updated presentation file being executable to display the presentation overlaid with the adjusted presenter image, and transmit, via the network interface, the updated presentation file to a remote presentation participant device.

Collaborative presentation system

A projector (N) of this invention employs a 380 mm diagonal, amorphous silicon LCD () for receiving light rays from a light source (), which achieves a small source size by employing four lamps () with small arc gaps () and a 'pinwheel' mirror () that overlaps light rays from each of the arc lamps into a single collimated light bundle. The small source size produces a small cone angle () of light through the LCD. A lens () directs the narrow cone of light though the LCD at an optimal angle for achieving a 1,500:1 contrast ratio. Only a 4&#xd7; magnification ratio is required to achieve a 170 cm (67 inch) diagonal projected image, which ratio enables projecting SXGA or greater resolution images with a five element projection lens (). The LCD achieves an operational life of at least 50,000 hours before projected images display color degradation.

Image projection system with multiple arc lamps and flyseye lens array light homogenizer directing polychromatic light on a liquid crystal display

Color gamut and luminance matching techniques for image display systems

An LCD projection display (,) houses a projection module (,) in which light propagates through an LCD module (,) at a shallow angle (,) that improves the contrast ration of and intentionally Keystones the image bearing light. The Keystoned light is reflected by a fold mirror (,) that is mounted at a 52&deg; upward angle, which introduces more intentional Keystoning. A projection lens (,) is mounted coaxial to a tilted optical axis (,), but the Keystoned image bearing light is refracted about 10&deg; off the optical axis and follows a Keystoning axis (,) through the projection lens. The light propagating from the projection lens is reflected by a main fold mirror (,) that is mounted at a 57&deg; angle from the vertical to project the image bearing light onto a 10&deg; slanted projection screen (,). Central light rays (,), image margin light rays (,), and the axial light rays (,) propagate unequal distances from the projection lens to the projection screen and are, therefore, unequally magnified to compensate for the Keystoning introduced by the LCD module. The steep mounting angle of the main fold mirror allows positioning it higher and more forward in the display, which reduces first surface reflections from ambient lighting and allows a significantly reduced depth dimension for the display.

Compact light path and package for liquid crystal projection displays

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.

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West Linn, OR, United States of America

John P Fogarty