Abstract: A polarel panel includes a sheet polarizer in intimate juxtaposition with a layer made up of regions of isotropic material interspersed with regions of liquid crystal material. In one embodiment, optical activity of the liquid crystal material rotates the electric vector of incoming linearly polarized light through 90.degree. in selected areas. In another embodiment, birefringence causes rotation of the electric vector of incoming linearly polarized light through 90.degree. in selected areas.

Abstract: A stereoscopic display system unambiguously tags the perspective view for left and right video fields by encoding at least one of the video fields with a unique code, then detecting the code in order to drive shuttered eyewear in synchrony therewith.

Abstract: A stereoscopic film projection system including one or more electro-optical light modulators used as part of, or in conjunction with, stereoscopic projection optics for the above-and-below film format employed for 35 mm theatrical cinema. The optical state of each modulator is voltage dependent, and the driving voltage therefor is generated in response to signals from a sensor positioned in the projector aperture. The sensor detects the presence or absence of index marks on the film. This arrangement insures that each subframe is maintained in a proper relationship with the optics' polarizers for preventing the projection of pseudostereoscopic motion pictures.

Abstract: Wireless active eyewear includes a frame having a front portion and a rear portion. A gasket and shutter assembly and a circuit board are held between the front and rear portions of the frame. The non-conductive gasket has electro-optical shutters integrally formed therewith and includes conductive plugs extending therefrom which electrically contact each of the electro-optical shutters and the circuit board. The frame includes temple arms hingedly attached thereto and an on/off switch which is actuated by opening and closing the temple arms.

Abstract: A method and apparatus for time multiplexing and demultiplexing two channels of picture information within a standard video channel. The method is specifically designed for field sequential stereoscopic display applications, but may be used for non-stereoscopic applications where conservation of bandwidth is required. The technique is superior to prior art commercially available stereoplexing approaches, and increases vertical resolution while decreasing stair-stepping of diagonal lines. The demultiplexing display controller of the invention can be manufactured at a low cost because its design takes advantage of commercially available integrated circuits.

Abstract: A fast switching liquid crystal device, a method for making such a device, and eyewear incorporating the device for use in a stereoscopic viewing system. The device achieves a fast response time and high contrast by increasing the twist of the nematic material to 270 degrees and orienting the tilt angle of the material to be consistent throughout the twist. The liquid crystal device is constructed to have two transparent, essentially parallel substrates which are spaced apart by a desired cell gap distance, and on which are deposited electrodes. The electrode surfaces are coated with a polymer material which is conditioned to provide a means of aligning the director axes of the liquid crystal material, and to maintain a desired tilt angle between the director axes and the electrode surfaces. A chiral dopant is added to the nematic liquid crystal material so that the pitch of the material is approximately twice the gap distance of the cell.

Abstract: A method and apparatus for reducing color shift resulting from the stereoscopic display of two polarized images by a pair of polarizing projectors each having a polarizing filter, or increasing the transmission of light which comprises the stereoscopic display, by placing a specially aligned retarder in the optical path between each polarizing projector and the corresponding polarizing filter.

Abstract: A method and apparatus for time multiplexing and demultiplexing two channels of picture information within a standard video channel. The method is specifically designed for field sequential stereoscopic display applications, but may be used for non-stereoscopic applications where conservation of bandwidth is required. The technique is superior to prior art commercially available stereoplexing approaches, and increases vertical resolution while decreasing stair-stepping of diagonal lines. The demultiplexing display controller of the invention can be manufactured at a low cost because its design takes advantage of commercially available integrated circuits.

Abstract: A method for overcoming optical artifacts which are an intrinsic part of the performance of twisted nematic liquid crystal shutter devices. When power is shut off from a conventional shutter device of this type, the device exhibits a brief periodic flickering called "bounce". When the power is turned on, the device exhibits a similar flickering effect, known as "stumble." When a pair of such devices are used as lenses in a stereoscopic selection apparatus, these artifacts, which contribute nothing to the device's performance, are obtrusive and disturbing to the user. By carefully controlling the voltage to each shutter in accordance with the invention while turning the shutter on or off, these artifacts are eliminated or substantially reduced.

Abstract: An electronic stereoscopic video camera for capture and playback of still or moving images. The camera of the invention employs a signal processing means to process the video output of left and right image sensors in order to locate the positions of left and right images in the camera's left and right image fields, respectively. As a result of comparison of the left and right image locations, control signals are generated for adjusting the effective position of one or both of the sensors in relation to a set of fixedly mounted camera lenses. The invention permits rapid and accurate control of a variety of video camera parameters by employing a self-correcting closed loop servo means in which the unmodified output of the left and right image sensors of a camera serves as feedback for generating control signals.

Abstract: A high dynamic range electro-optical shutter for stereoscopic and other applications, and a method for increasing the dynamic range of an electro-optical shutter system. The shutter of the invention is derived from an existing electro-optical shutter by adjusting the tilt angle of the plane of the shutter's surface in the optical path of the apparatus in which it is employed. The invention is based upon the finding that light rays transversing an electro-optical shutter which are not perpendicularly to the plane in which a surface of the shutter lies, can have a significantly higher dynamic range than axial rays. In accordance with the invention, the angle at which the shutter is mounted in an apparatus is adjusted to produce a dynamic range which is high enough for the intended application. By mapping the pattern of spatial distribution of dynamic range, it is possible to design and produce shutters which are low in manufacturing cost, yet have performance which equals that of more costly shutters.

Abstract: A still or moving image electronic stereoscopic video camera for image capture and playback, with image sensors having variable effective position to avoid inherent geometric distortions which would otherwise cause undesirable vertical parallax. Horizontal shifting of the effective image sensor position is used to correctly converge the image without the introduction of distortion, and optionally also to control recentration of zoom optics, and to achieve interdigitated lenticular stereoscopic displays. In some embodiments, simple mechanical elements are provided for physically moving the imaging sensor.

Abstract: A liquid crystal shutter system for selecting fields of a field-sequential image, by transmitting the field-sequential image, with a synchronization signal, to one or more remote liquid crystal cell shutter assemblies. Each shutter assembly transmits selected fields of the field-sequential image in response to a drive signal, and includes a drive circuit for receiving the synchronization signal and generating each drive signal in response to the synchronization signal so that each drive signal has transitions synchronized with image fields. The drive circuit is capable of rapidly processing short duration synchronization signals with very low power consumption. In one embodiment, two liquid crystal cell assemblies are mounted in an eyeglass frame and used as a wireless selection device for a field-sequential stereoscopic image.

Abstract: An achromatic liquid-crystal shutter with high dynamic range, good transmission, and high speed. The inventive shutter reduces the phenomenon of "ghosting" (image doubling) that typically occurs in conventional plano-stereoscopic CRT displays due to the low dynamic range of surface mode liquid crystal electro-optical shutters included within such displays. The inventive shutter reduces crosstalk, thus allowing comfortable fusion to take place. In one preferred embodiment, the inventive shutter system is driven by a carrier-less voltage signal having time-averaged voltage substantially equal to zero, so that a simple, low power driving circuit suffices to drive the shutter. A pair of the inventive achromatic shutters may be employed in a wireless mode as a selection device for a field-sequential stereoscopic electronic display system.

Abstract: An achromatic liquid-crystal shutter with high dynamic range, good transmission, and high speed. The inventive shutter reduces the phenomenon of "ghosting" (image doubling) that typically occurs in conventional plano-stereoscopic CRT displays due to the low dynamic range of surface mode liquid crystal electro-optical shutters included within such displays. The inventive shutter reduces crosstalk, thus allowing comfortable fusion to take place. In one preferred embodiment, the inventive shutter system is driven by a carrier-less voltage signal having time-average voltage substantially equal to zero, so that a simple, low power driving circuit suffices to drive the shutter. A pair of the inventive achromatic shutters may be employed in a wireless mode as a selection device for a field-sequential stereoscopic electronic display system.

Abstract: A stereoscopic camera system is disclosed for producing an "over-and-under" format suitable for stereoscopic video transmission and presentation. The stereoscopic camera system utilizes conventional 60 Hz cameras which are slightly modified in order to utilize only half of the horizontal sweep lines to form the respective left and right subfields in the over-and-under format fields.

Abstract: A stereoscopic television system comprising single or double camera designs adapted to televise twin perspective points of view, which are the source for encoding alternate odd and even fields with right and left images, and a television receiver for displaying such images with either passive or infra-red signaled or internally clock controlled active selection devices. The receiver and the preferred embodiment of the camera use field storage devices to record and playback picture information in an appropriate sequence in such a manner to eliminate flicker and to overcome spurious temporal parallax effects. The receiver uses monochromatic or color television tubes, like those of present manufacture, but employs means to double the scan rate so that, for example, an effective 60 fields for each eye for domestic receivers, and 50 fields for each eye, for certain foreign receivers, is achieved. Field storage or buffer circuits allow the doubling of the number of fields without doubling of the bandwidth.

Abstract: An improved stereoscopic television system is disclosed, having a great deal of compatibility with the existing commercial television infrastructure. Flicker is eliminated while preserving the existing bandwidth allowing the stereoscopic video signals to be handled with conventional apparatus such as video tape recorders, video disks, or broadcast equipment. In the present invention the number of fields per second is twice that of he standard field rate. When displayed on an unmodified receiver or monitor, each subfield image appears to be anamorphically compressed in the vertical direction by a factor of two. A blanking area and/or vertical sync pulse separates the two subfields.

Abstract: Right and left projected image fields of stereoscopic images must have even illumination. If audiences are subjected to uneven illumination intensity of right and left pairs of stereoscopic images, the result for most people will be discomfort. Complimentary colored filters are used in the optical paths of the right and left projected fields, and the resultant additive color mixture is used for evaluation of symmetrical illumination. A means is thus presented for quickly, accurately, and inexpensively calibrating right and left image fields for both equal and even illumination intensity.

Abstract: Paired movie cameras, each having synchronized movements and in phase shutters, are provided with focus and zoom optics of identical, but conventional and commercial manufacture. The paired lenses are first rotated relative to one another to obtain a coincidence between the centration vector for each lens for either zoom or focus. Once the centration vectors are aligned identically on a polar basis, mounting to the camera with provision for synchronous zoom between the respective cameras thereafter occurs. Typically, and before each stereo shooting, the zoom optics are set to a maximum magnification and registered to the appropriate distance with the lens finders and reticules. Upon change of the focus and/or zoom setting, a variable prism affixed to one camera is moved relative to the remaining camera to maintain identical centration between the respective lens cameras.