Kaiser Aerospace & Electronics Corp.

Rockwell Collins, Inc.

Kaiser Aerospace & Electronics Co.

Kaiser Aerospace and Electronics Coporation

Michael H Kalmanash

Sushil Krishnamurthy

James L Fergason

Arthur Louis Berman

Vijay M Sethna

Gayathri Sundaresan

The projection screen assembly minimizes speckle while preserving high ambient viewability. The screen assembly, having a light-source side and a viewing side, includes a screen layer, a polarizing contrast filter, and a speckle contrast reducing layer. The screen layer disperses light passing through the screen assembly from the light-source side. The polarizing contrast filter is disposed on the viewing side of the screen layer and reduces ambient glare. The speckle contrast reducing layer is disposed on the light-source side of the screen layer and reduces speckle formed in projected images on the viewing side of the screen assembly.

Projection screen with reduced speckle

A secondary image suppression system (SISS) for minimizing secondary ghost images in a screen assembly for a rear projection system. The secondary image suppression system includes a circular polarizing assembly positioned to receive light from a rear projection lens of a rear projection system. The circular polarizing assembly includes a linear polarizer and a quarter wave retarder. The linear polarizer and the quarter wave retarder are serially positioned relative to each other and are assembled with a high power Fresnel lens using index matching media such that internal reflections are minimized. The high power Fresnel lens is positioned to receive output from the circular polarizing assembly. During use, light from a projection lens of a rear projection system is introduced through the circular polarizing assembly and through the high power Fresnel lens toward a viewing screen. Any significant secondary ghost images are eliminated by the circular polarizing assembly. The SISS may be combined with a high contrast screen assembly to improve high ambient contrast while avoiding the necessity for beaded films or other structured screens that could cause viewing artifacts.

System for eliminating secondary images in rear projection systems

An integrated dual day night backlight includes a flat channel light source with an auxiliary night light source suitably filtered to remove infrared components from the illumination. In alternative embodiments, the night light can be a separate bulb or it can be separate light channels within the flat channel source. The night illumination is directed through the edge of the light transmissive face plate that covers the main or day channel. The light directing means can be an inner reflecting surface of the face plate or can be a separate reflective element that redirects the illumination from the night channel through the edge of the transmissive face plate.

Integrated dual mode flat backlight

An active matrix portion of an active matrix liquid crystal display is created by a process that fabricates silicon wafers containing a plurality of transistors in an array necessary for the display. A plurality of these wafers are aligned and affixed to a transparent substrate. All silicon other than the active circuits is removed. Transparent and conductive pads as well as vertical and horizontal driver lines are added directly onto the substrate and interconnect with the individual transistors. The resulting pixels are slightly undersize but will be in perfect alignment in rows and columns.

Quasi-tiled active matrix display

An electrically activated infrared filter utilizes a mixture of infrared absorbing dyes in liquid crystal which normally presents a substantial cross section of dye to absorb the infrared component of impinging light. Polarizing light to be parallel to the direction of liquid crystal alignment enhances the absorption of infrared components. In an alternative embodiment, a chiral additive to the liquid crystal solution increases the dye cross section density which, by absorption, attenuates a higher proportion of the infrared wavelengths. A predetermined voltage differential across the cell aligns the liquid crystal and dye molecules to the voltage gradient, presenting a substantially non-absorptive path to the infrared components of impinging light.

Nightvision compatible display with electrically activated infrared

A liquid crystal display assembly includes an untwisted nematic liquid crystal cell structure. The light transmittance of each pixel element of the assembly is a function of the pixel drive voltage. A phase compensating plate reduces the voltage necessary to permit switching, permitting compatibility with conventional thin film transistor (TFT) arrays but capable of greatly shortened response times. The configuration includes a combination linear polarizer and quarter wave plate which functions as a circular polarizer for blocking reflections from internal specularly reflecting surfaces within the liquid crystal display, thereby enhancing high ambient viewability.

High speed, high ambient viewability liquid crystal display assembly

The efficiency of LC displays is improved by the use of a polymeric chiral nematic liquid crystal rear polarizer and reflective backlight housing which increases the net transmission of light and, at the same time, reduces the weight of the assemblage and increases battery life by utilizing lower levels of illumination. The polymeric chiral nematic liquid crystal can be a freestanding film or films, or can be supported by a single glass substrate. The liquid crystal polarizer can have a bandwidth sufficient to transmit electromagnetic radiation across the entire visible spectrum.

High efficiency chiral nematic liquid crystal rear polarizer for liquid

A backlight system for liquid crystal device display is equipped with a dual lighting system for day viewing and night viewing. The day lighting system uses conventional fluorescent or incandescent lamps for full color display during daytime use. The night lighting system uses a lower intensity light source. The day lighting system is disabled while the night system is in use. The dual lighting system provides an extended dimming range compared to what would otherwise be available.

Wide dimming range backlight for liquid crystal devices

A backlight system for liquid crystal device display is equipped with a dual lighting system for day viewing and compatible with night vision systems. The day lighting system uses conventional fluorescent or incandescent lamps for full color display during daytime use. The night lighting system uses a light source which is either filtered to remove infrared and near infrared wavelengths or which is chosen from a class of sources which does not emit such wavelengths. The day lighting system is disabled while the night system is in use.

Backlight for liquid crystal devices

An apparatus and method for providing optical switching or color selection capability uses cholesteric liquid crystals which reflect and transmit circularly polarized light and a variable wave retarder element together with phase reversing mirrors which recapture and recombine the reflected circularly polarized light. With the retarder element in a first state, first orientation circularly polarized light is completely transmitted and second orientation circularly polarized light is redirected. Alternatively, a color selection assembly is provided through the use of a combination of cholesteric light crystals in which light of a first color is given a first polarization orientation and light of a second color is given a second polarization orientation. Depending upon the state of the retarder either the first or second color is transmitted to a desired target.

Optical switch and color selection assembly

A high precision optical filter includes a wideband filter element and a cholesteric liquid crystal notch filter element. In one embodiment, a wideband infrared filter blocks infrared wavelengths beginning at a nearly visible corner wavelength and a cholesteric liquid crystal filter blocks transmission of infrared wavelengths in a precise narrow band that includes the corner wavelength and that extends down to visible wavelengths. The liquid crystal filter may include a polymer for maintaining maximum reflectivity of the filter near the corner wavelength over an anticipated operating temperature range. The combined optical filter may be fabricated by depositing a matched pair of liquid crystal cholesteric films on a glass infrared filter element. In another embodiment, an optical filter according to the invention forms an eyepiece in a night vision goggles assembly for blocking visible light. The filter may also be mounted on a display device to block the transmission of undesirable infrared emissions at the source.

Infrared filter using cholesteric liquids

A field sequential color shutter display system including a light source emitting light rays having substantially first and second different primary colors. First and second light polarizing filters are included. The filters are aligned in optical communication with the source. Each filter includes a color selective polarizing filter having substantially orthogonally oriented absorption axes. The first absorption axis of each light polarizing filter passes linearly polarized light of the first color and a uniform first polarization. The second absorption axis of each light polarizing filter passes linearly polarized light of both the first and second colors and a uniform second polarization. Variable optical retarding filters are disposed between the first and second light polarizing filters. Switching filters are in communication with the variable optical retarding filters to selectively provide first and second switching states to produce respective first and second amounts of optical retardation to develop, over a relatively broad range of viewing angles, a light output through the second light polarizing filter of either the first color, or, a composite light output containing both the first color, having both the first and second polarizations, and the second color having only the second polarization.

Method and apparatus for multi-color display

A stereoscopic display capable of displaying monochromatic or colored views of moving, three dimensional scenes comprises means for sequentially projecting alternate ones of successive pairs of substantially monochromatic images corresponding to right-eye and left-eye perspectives of the scene at a display rate sufficient to avoid a perception of flicker in the images. A variable polarizer is used to circularly polarize alternate ones of the images in respectively opposite senses synchronously at their projection rate. The images are analyzed by highly-transmissive eyewear comprising at least one pair of oppositely-sensed cholesteric liquid crystal circular polarizers tuned to the particular color wavelength of the images and disposed, one over each eye, to transmit appropriately-polarized images to corresponding eyes and to reflect inappropriately-polarized images away therefrom.

Stereoscopic display

An apparatus and method for producing a color display from a substantially monochromatic source utilizes a liquid crystal cell combination together with a plechroic filter to differentially polarize the light components comprising the light emitted from the source. The liquid crystal cells are connected in push-pull fashion to individually retard light by one fourth of a wave as a function of the control signal applied to them. A fourth wave plate followed by a linear polarizer completes the optical combination. A signal at a first level applied to the cells causes transmission of one component color and blocks the other. A signal at a second level blocks the one component color and transmits the other. An intermediate level signal transmits both colors, resulting in a third, combination color.

Growing community of inventors

Los Altos, CA, United States of America

Michael H Kalmanash