Abstract: A multiple element lens system for projecting images generated from curved surfaces. A spherical projection lens is provided along a projection axis. An aspheric plate follows the spherical lens, which is followed by a second spherical projection lens. Parfocalizing separate curved image surfaces of different primary colors permits a narrow spectral bandwidth lens system, having an improved speed and resolution, providing combined full color projected images.

Abstract: Disclosed are systems and techniques for image generation applicable in general to any long persistence display device, particularly one in which contrast builds over a number of frames. The display device disclosed in detail by way of example herein is a high resolution cathodochromic CRT (CCRT) in a projection system. The system includes a deflection generator for the display device capable of writing to at least individual image lines in any order and, in some embodiments, to individually-addressed pixels. In raster-scanned embodiments, an image memory is included, capable of storing pixel data on a line-by-line basis. An image controller serves to read particular lines from the image memory and to write corresponding image lines on the display device. In one embodiment, those scan lines which have no picture information (e.g.

Abstract: An aplanatic image combiner. At least two image generating cathode ray tubes are provided having curved concave phosphor image generating surfaces. A set of dichroic mirrors are provided to combine images from each of the curved surfaces into a single combined image. A lens is positioned to transmit the combined image to an image magnification system. The lens has a curved surface forming an exit aperture for the image combiner. The radius of curvature of the lens is configured to be substantially the same as the radius of curvature of each of the concave image generating surfaces of the cathode ray tube. An image is generated to an image magnification system without generating any field aberration or astigmatic and chromatic aberration requiring correction in the magnification system.

Abstract: Disclosed are systems and techniques for alignment of CRT-based display systems, particularly those employing a high resolution cathodochromic projection CRT. The disclosed techniques permit all major CRT-related alignment to be performed at a factory or other centralized facility, with automatic precision alignment in the field of the overall display system, including a CRT assembly as one element. A replaceable, standardized CRT subsystem includes a CRT assembly, itself subject to sample variations, and a non-volatile personality memory, such as an EEPROM, having stored parameters specifically applicable to the CRT assembly on an individual basis. The CRT assembly has no field adjustable parts, but does include elements for electron beam control, such as electromagnetic coils for focus and deflection permanently affixed to the CRT. Thus at the factory, a skilled operator having appropriate equipment available performs an electronic alignment procedure with reference to a particular CRT.

Abstract: A multiple tube projection television system. At least two image generating cathode ray tubes are provided, having an image generating surface which is concave. The radius of curvature of the image generating tubes is selected to be between 1.2 and 2 times the image diagonal of each tube. Dichroic mirror means are provided to combine the images produced from each tube. A projection lens system is positioned at an optical distance from each tube which is substantially equal to the radius of curvature of the concave phosphor surface. The combination provides for an optimum amount of light to the entrance aperture of the projection lens system.

Abstract: An improved method for erasure of an image target in a CCRT projection system includes the steps of projecting a defocused electron beam onto the target forming a scan line, establishing an energy level below the erase threshold to prevent erasure of any portion of the target within the single line, scanning multiple lines across the full target, and overlapping the scan lines sufficiently to provide integrated heat energy to cause erasure. The energy level is established at about 75% of the erase threshold or about 0.3 joule/cm.sup.2. The power is preferably set at 30 kv and 400 microamps with a single scan line being established at 0.056 inch. Preferably, the scan line is set to overlap 5-12 times to cause erasure, with the optimum being approximately 8 overlaps. In the related CCRT set up of the erasure mode, after overlapping the scan lines, the energy level is gradually increased until the integrated heat energy is sufficient to cause erasure.

Abstract: An elongate elastomeric seal member including a first portion to be partially received in an elongate groove of a selected element where the groove has opposite sides and a base connecting the sides and a second portion extending outwardly from the opposite edges of the groove to sealably engage a sealing surface adjacent the element where fluid pressure is selectively applied to at least one side of the seal and where the seal, in cross section, includes a central body with first and second spaced feet extending outwardly therefrom to be received in the groove and engage the sides and base of the groove and third and fourth feet extending outwardly from the central element to slidably engage the sealing surface wherein fluid can be applied to at least one of the third and fourth feet to urge one of said third and fourth feet to sealing relation with said sealing surface.

Abstract: A monitor for a vapor compression refrigerant system using halocarbon refrigerants that accumulates contaminant gases present or generated in an operating system and provides a readout indicative of the presence of significant amounts of contaminant gases which readout serves to provide an indication of an incipient malfunction of the refrigerant system. Embodiments of the monitor are disclosed which provide continuous and automatice purging of the contaminant gases from the system using perm-selective membranes with or without provision for providing indicia of the presence or build-up of contaminant gases in the monitor.

Abstract: A sheet metal attachment system and method for the installation of underground mine brattices of the type in which a gas impervious barrier of malleable sheet metal is retained on a peripheral framework of slotted beams. The fastening system involves pre-mounting a plurality of bolts projecting from one face of the framework as piercing pins so that the sheet metal may be initially applied by forcing it over the pins. The pierced sheet metal is then drawn against the framework by a multi-apertured washer plate and barrier mounting nut threaded onto the bolts.

Abstract: Molten slag is introduced through the lower portion of a crucible device into the bottom of the remelting zone in an electroslag remelting process using single or plural consumable electrodes in an amount sufficient to achieve a predetermined depth in the remelting zone. The achievement of the predetermined depth is signalled when current flows as a result of the slag level contacting and closing a circuit through an energized electrode disposed in the remelting zone. The crucible has a bottom plate at its lower end, the bottom plate has a recess in its top side and a piece of metal is inserted in the recess to provide electrical contact between the piece of metal and the bottom plate the piece of metal in the recess in the bottom plate is connected by a center tap line to an electric current source which passes through the electrode(s), the slag and the piece of metal during initial remelting.