Abstract: 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.

Abstract: 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.

Abstract: A dual lamp light source utilizes a polarizing beam splitter to provide an output beam from one or the other or both sources. One lamp is positioned adjacent a face whose plane is parallel to the optical axis of the beam splitter and whose output is internally reflected. The other lamp is positioned adjacent a rear face of the beam splitter so that its output is the output of the beam splitter.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A high voltage color switch for a beam penetration CRT includes a constant current driver which provides a bias current to the high voltage transformer in the first color write period when the baseline color is being displayed. One or more secondary colors can be displayed during a second color write period during which a switch connects the transformer to a conventional voltage driver that provides the needed voltage swing. At the end of a secondary color write period the constant current driver is again connected to reset the flux level in the transformer to one end of its dynamic range. During a core reset interval only a small voltage offset appears on the anode of the CRT so that color information written in the baseline color appears without any perceivable change to a viewer. At the end of the core reset period the constant current source continues to supply a constant bias current to the primary winding of the transformer to maintain the flux level at one end of its dynamic range.

Abstract: A high voltage color switch for a beam penetration CRT is well suited to generating a color write in one or more random colors during the retrace interval of a TV raster scan, or the like. The scanning period of the TV raster is in the baseline color for maximum resolution and brightness. A driver connected to the high voltage transformer includes a low voltage power supply which has one portion controlled by a switch. During the color write period the switch is closed so that the driver can provide a suitable waveform to the transformer to obtain the required swing. During the raster scan, the switch is open so that the magnetizing current in the transformer can be reset over the entire TV raster scan interval causing only a slight offset in the baseline color.

Abstract: A color switch for a beam penetration CRT can display a randomly selected color in a first color write period, and immediately after the first color write period the magnetizing current in the high voltage transformer is reset during a second write period in a complementary color. A high voltage power supply has an output voltage selected to provide a baseline color whose voltage level is intermediate the voltage range of the CRT anode. A pair of drivers are connected to either end of the primary winding of the high voltage transformer and generate a voltage differentially across the primary winding that drives the voltage level either upwardly or downwardly from the baseline level. Immediately after the first color write period, a second color write period is formed in a complementary color by transitioning a pair of input switches.

Abstract: A color switch for a beam penetration CRT includes a return path through a pair of reverse biased diodes to recapture a substantial amount of the energy associated with changing the voltage on the anode of the CRT for a write period in a non-baseline color. A driver circuit, which includes the low voltage power supply, is connected through a switch to one end of the primary winding of a transformer. The primary winding is also connected through one of two diodes to each half of the low voltage power supply for the driver. By opening the switch at the end of a color write period in a non-baseline color, the rapid decrease in the current through the primary winding of the transformer to restore DC balance of the magnetizing current in the transformer core forms a reverse voltage which is returned to the low voltage power supply through the diodes.

Abstract: A high voltage color switch for beam penetration CRT has two operating modes, the first of which is well suited to displaying a sequential group of colors on the faceplate of a CRT, and the second mode of which is well suited to displaying a random color that varies from a preselected baseline color. A high voltage power supply has an output voltage level which is selected to provide a predetermined baseline color when presented through the secondary winding of a transformer to the anode of a CRT. The primary winding of the transformer is connected through a first switch to the output of a driver. A feedback loop from the output of the driver senses the DC voltage level associated with the input waveform and biases the input of the driver to force the level of DC voltage presented to the primary winding of the transformer to zero.

Abstract: An improved sequential color switch for a beam penetration CRT includes a high voltage power supply and a high voltage transformer. A feedback circuit senses the DC level in the signal waveform applied to the transformer and feeds it back to the input of a driver. A low-pass filter connected to the input of the driver also senses the DC level in the signal waveform applied to the driver and adjusts the reference input of the high voltage power supply to correspondingly change its DC high voltage output level. Essentially, this removes any DC level from the primary winding of the high voltage transformer while at the same time adjusting the output level of the high voltage power supply connected to the secondary winding of the transformer by an amount which is proportional to the average DC level of the input signal waveform.