Abstract: An image projector has an optical path including, from upstream to downstream, a light source, a light pipe, a polarization conversion prism, a positive lens group and a light valve. The light pipe has an outlet and an inlet, and is constructed to receive light from the light source and to produce a unique projection display format as light is transmitted therethrough. The polarization conversion prism recycles light to optimize the amount of light that is properly polarized in the system. The positive lens group includes at least one positive lens positioned downstream of the polarization conversion prism. The positive lens group images the outlet of the light pipe onto the light valve.

Abstract: A multimedia projector comprises a optical frame that mounts, from back to front, a light source, a back fresnel lens, a back polarizer, an LCD display object, a front polarizer, a front fresnel lens, and a front lens group for projecting images formed by the LCD display object. To provide contrast adjustment, a contrast adjustment mechanism is attached to the back polarizer to permit the manual selective tilting of the back polarizer about an axis extending perpendicular to the front polarizer, in order to optimize contrast of images projected by the front lens group.

Abstract: An image projector is provided with a light source and a light valve positioned downstream of the light source. An optical path is defined between the light source and the light valve. To accommodate various image viewing formats, a plurality of optical integrators is positioned between the light source and the light valve. Each of the plurality of optical integrators is movable laterally of the optical path and is positionable in the optical path. Light from the light source is transmitted to the light valve through the particular optical integrator positioned in the optical path. Each optical integrator is constructed to produce a unique display format for the light transmitted therethrough to the light valve, in order the accommodate different display formats such as standard and letter-box without wasting light.

Abstract: A method for producing a digital video signal from an analog video signal, the analog video signal including an analog video data signal that is raster scanned in lines across a CRT screen to form consecutive frames of video information, the raster scanning controlled by use of a horizontal synchronizing signal (H.sub.snyc) that controls a line scan rate, and a vertical synchronizing signal (V.sub.snyc) that controls a frame refresh rate, to produce consecutive frames of video information, wherein the digital video signal is produced by generating a pixel clock signal with pixel clocks for repetitively sampling instantaneous values of the analog video data signal, and digitizing the analog video data signal based on the pixel clock sampling. An expected width E, measured in number of pixel clocks, of a video image producible by the analog video signal is estimated, and an actual width W, measured in number of pixel clocks, of the video image producible by the analog video signal is calculated.

Abstract: An image projector is provided with a light valve having an upstream side and an downstream side. A light source is disposed on the upstream side of the light valve, and a front lens system with an entrance pupil is disposed on the downstream side of the light valve. A back optical system is disposed between the light source and the light valve. The back optical system has a nonimaging device with an exit aperture that is either imaged into the entrance pupil of the front lens system (Kohler) or imaged onto the light valve (Abbe).

Abstract: The present invention includes a multimedia projection system coupling apparatus having a coupling converter for interconnecting at least one multimedia source and a multimedia projection display system. The coupler system includes at least two source cables that extend from the multimedia source and carry to the coupling converter media signals corresponding to different media, such as video and system control. The coupling converter delivers corresponding media signals to a projector terminal from which a projector cable extends to the projection display system. In the preferred embodiment, the coupling converter includes signal format conversion circuitry for converting each media signal or its component to a differential signal format, and the projector cable preferably includes a separate twisted pair of wires for carrying each of the differential format signals.

Abstract: A method for producing a digital video signal from an analog video signal, the analog video signal including an analog video data signal that is raster scanned in lines across a CRT screen to form consecutive frames of video information, the raster scanning controlled by use of a horizontal synchronizing signal (H.sub.sync) that controls a line scan rate, and a vertical synchronizing signal (V.sub.sync) that controls a frame refresh rate, to produce consecutive frames of video information, wherein the digital video signal is produced by generating a pixel clock signal with pixel clocks for repetitively sampling instantaneous values of the analog video data signal, and digitizing the analog video data signal based on the pixel clock sampling. An expected width E, measured in number of pixel clocks, of a video image producible by the analog video signal is estimated, and an actual width W, measured in number of pixel clocks, of the video image producible by the analog video signal is calculated.

Abstract: A multimedia projector comprises a optical frame that mounts, from back to front, a light source, a back fresnel lens, a back polarizer, an LCD display object, a front polarizer, a front fresnel lens, and a front lens group for projecting images formed by the LCD display object. To provide keystone distortion correction of projected images, the front fresnel lens is manually and selectively tiltable about an axis extending parallel with the plane of the LCD display object. The selective tilting is accomplished by a manually movable fresnel actuator with a cammed surface. A control arm extends between the fresnel actuator and the fresnel lens, and rides on the cammed surface such that a relatively large movement of the fresnel actuator produces a relatively small adjustment in tilt of the fresnel lens in order to permit fine adjustment of the fresnel lens tilt.