Abstract: Liquid crystal mixtures are disclosed which contain 30-60% of a Schiff's base nematic liquid crystal compound, 25-65% of a second nematic liquid crystal compound selected from the classes of azoxy, ester and biphenyl, and 5-15% of a triphenyl compound to raise the isotropic transition temperature. This combination results in liquid crystal compositions having unexpectedly wide nematic temperature ranges.

Abstract: A network of two or more microprogrammed digital processors is provided which permits operation of the individual processors independently or as linked processors for transferring real time control information at the micro level to establish microprogram control which is supplied from the processor that is processing the data determining the control sequence, resulting in dynamic master/slave relationships, with high performance, by eliminating the need to transfer data used to influence microprogramming sequencing. Next control memory address source designators within each processor, selectively enable microprogram control memory data sources of either processor when the control memory address busses of each processor are linked together. Upon unlinking of the address busses, each next control memory address source designator selectively enables a source only within its own processor, such as a branch address latch source, operation code mapping memory source, and a microsequencer source.

Abstract: A plurality of circuit boards having male pin connectors are connected to a mother board having female pin receptor connectors, each circuit board being supported by a pair of grooved edge guide means. After the circuit boards are inserted into the device, a cover having a resilient foam pad on the inside surface thereof is closed wherein the foam pad resiliently presses against the upper edges of the circuit boards to hold them into position and maintain good electrical integrity with respect to the aforesaid connectors at the bottom portions of the circuit boards. Edge connectors may be plugged into the sides of the boards for further electrical access, and the heights of the edge guide means are high enough so that lower portions of the edge connectors are blocked and held in position by upper portions of the edge guides to prevent the edge connectors from being dislodged or loosened from the sides of the circuit boards.

Abstract: Transfer apparatus for receiving a printing plate from a first station in a first horizontal orientation and for transferring the plate to a second station in a second orientation which is both vertical and rotated 90.degree. relative to the first orientation. The apparatus comprises a receptor bin for supporting the plate, which receptor bin is, in turn, supported solely by a single rotatable shaft. By mounting the shaft to the receptor bin at a precise angular orientation, rotation of the shaft about its own axis will carry the receptor bin and the plate supported on it from the first orientation to the second orientation to transfer the plate to the second station.

Abstract: A lens carriage is mounted upon a cylindrical way at a left-hand portion thereof, and is supported at a right-hand portion thereof by a single roller which rolls over a flat plate way during translation of the carriage parallel to the optical axis of the phototypesetter. A brake shoe coupled to the carriage is spring biased against the lower surface of the flat plate way, and as a result, there is no play or looseness in the arrangement and yet imprecise positioning of the way elements in space, to save manufacturing costs, results in modest and repeatable shifts of the lens element mounted upon the carriage in directions transverse to the optical axis.

Abstract: An acousto-optic deflector that utilizes second order diffraction in a birefringent crystal provides doubled resolution while maintaining high diffraction efficiency. For the second order birefringent deflector employing a paratellurite crystal, 1200 spot resolution was achieved with a 24 MHz bandwidth and 25 .mu. sec access time. This maximum number of spots is twice that obtainable in a conventional first order acousto-optic deflector.

Abstract: A plurality of outwardly and radially extending font segment support arms are coupled to a central hub which is rotated to sequentially present the letters formed upon the segments to an optical imaging station which selectively projects optical images of the letters upon a photosensitive medium. Vertical shoulder portions are precision machined upon outer portions of the radially extending support members for precisely positioning the arcuate character tracks on the segments with respect to the imaging station. Horizontal plates are affixed to the radially extending support members to support the segments against gravity and centrifugal force is employed to precisely seat the segments against the vertically oriented shoulder portions upon rotation of the hub.

Abstract: A magnification signal of 64 - 100% is applied as an input parameter to a specially designed relaxation oscillator which produces a pulse train wherein the pulses thereof have a duration which vary in linear fashion with respect to the magnification input signal, the relaxation oscillator employing a constant current source in series relationship with an integrating capacitor which produces a saw tooth signal having a slope which is constant regardless of variations in the amplitude of the magnification input signal. The output pulses from the relaxation oscillator are counted to define an exposure control interval which changes linearly with respect to the input magnification signal.

Abstract: Apparatus for recording a serial line of electrical data as a spatial array of optical data. The apparatus employs an acousto-optic device through which the electrical signal to be recorded is passed as a continuous acoustic wave. The device is illuminated by a laser and imaged onto a recording medium to form an image of the acoustic wave passing through the device. By pulsing the laser just as the acoustic wave fills the device, a line of optical data can be recorded which will correspond to the acoustic wave in the device. By indexing the recording medium and reimaging every time a new acoustic wave just fills the device, an entire raster may be recorded.

Abstract: A protective container for font disc segments. The container includes a housing portion for supporting the segment and a cap portion for closing the housing portion and, at the same time, for locking the segment against movement within the housing portion. More particularly, the housing portion includes an inner casing supported within an outer casing with the inner casing being of relatively flexible material and having side wall portions extending beyond the top opening in said outer casing. After insertion of the segment into the inner casing, the cap portion is placed around the extended wall portions of said inner casing and, in doing so, will not only close the container, but will also force the walls of the inner casing inwardly against the segment to positively lock it against movement. Upon removal of the cap portion, the side walls of the inner casing will spring outwardly to release the segment for easy removal from the housing.

Abstract: A linear measuring system for precisely measuring distances along a rather long measurement axis. The apparatus includes an endless measuring cable which is held under tension between a metering drum at one end of the system and an idler drum at the other end. The measuring cable is wrapped around a groove, which has a semicircular cross sectional shape, on the circumference of the measuring drum, and is wrapped similarly around the idler drum. The cable is coupled to an object, the movement of which is to be measured, and movement of the object results in linear movement of the cable and rotational movement of the metering drum. A rotary encoder, which produces a digital output signal, is coupled to the metering drum to measure linear movement of the object. The accuracy of the measurement depends upon maintaining a constant measuring diameter of the metering drum and the measuring cable, and also upon maintaining a tight frictional bond between the measuring cable and the metering drum.

Abstract: A plurality of outwardly and radially extending font segment support arms are coupled to a central hub which is rotated to sequentially present the letters formed upon the segments to an optical imaging station which selectively projects optical images of the letters upon a photosensitive medium. Vertical shoulder portions are precision machined upon outer portions of the radially extending support members for precisely positioning the arcuate character tracks on the segments with respect to the imaging station. Horizontal plates are affixed to the radially extending support members to support the segments against gravity and centrifugal force is employed to precisely seat the segments against the vertically oriented shoulder portions upon rotation of the hub. A stationary stage plate together with a ramp element provide for easy and rapid insertion and removal of font segments from the front of the phototypesetter.

Abstract: Liquid crystal mixtures are disclosed which contain 30-60% of a Schiff's base nematic liquid crystal compound, 25-65% of a second nematic liquid crystal compound selected from the classes of azoxy, ester and biphenyl, and 5-15% of a triphenyl compound to raise the isotropic transition temperature. This combination results in liquid crystal compositions having unexpectedly wide nematic temperature ranges.

Abstract: Apparatus for supporting a sheet of photosensitive material in the image plane of an optical imaging system for exposure thereat. The apparatus includes a first cover plate assembly having a transparent cover plate and a second backing plate assembly including a relatively flexible backing sheet. The cover plate assembly is driven into contact with the backing plate assembly with the photosensitive sheet to be exposed supported therebetween such that an air-tight chamber is defined between the cover plate assembly and the relatively flexible backing sheet. The air-tight chamber is then evacuated through the cover plate assembly, and as it is evacuated, the flexible backing plate will be sucked towards the cover plate assembly and drive the photosensitive sheet into firm contact with the transparent cover plate.By the use of the flexible backing plate, the chamber can be evacuated very rapidly, for example, in two or three seconds.

Abstract: A main programming memory device is coupled to an arithmetic logic unit through controllable gating circuitry which permits the majority of control data within the main memory to be sequentially transmitted to the arithmetic logic unit for control of arithmetic data therein. An instruction designation source controls a main memory address device which in turn is coupled to the main programming memory to initiate data readout to the arithmetic logic unit, through the gating circuitry, such instruction designation source also being coupled to a function memory which contains arithmetic logic data unique to particular instructions to be executed.

Abstract: A contact screen positioning device supports a flexible bowed halftone screen over a vacuum platen having a sheet of film thereon so that as the positioning device moves slowly down over the vacuum platen, central portions of the contact screen initially press against central portions of the platen and less and less centralized portions thereafter sequentially press against less and less centralized portions of said vacuum platen, to produce a rapid sweeping of air toward outer portions of the platen for rapid positioning of said screen over said platen without entrapped air pockets being formed between the screen and the film on the platen.

Abstract: An automatically focusing optical system for copiers, duplicators and other reproduction equipment having a variable magnification capability. The auto-focusing mechanism comprises a camming means for moving a mirror or other component of the optical system to maintain focus throughout the magnification range of the system. The camming means is additionally designed to be adjustable in such a way that it can accommodate imaging lens systems which differ in focal length within the normal manufacturing tolerance band, and thus replace the family of cams utilized in the prior art to accommodate lenses of different focal length.

Abstract: A solar energy collector of low cost and high thermal efficiency is disclosed having a heat trap produced by zigzagging a thin strip of polyethylene terephthalate between opposite sides of the trap while wrapping the strip about rows of dowels positioned at opposite sides of the frame of the solar collector. A window of soda lime glass filters UV radiation to inhibit discoloration of the plastic heat trap walls. An absorber plate having fluid pipes therein is positioned underneath the heat trap and a first layer of fiberglass, and a second layer of polyurethane foam are positioned below the absorber plate. The fiberglass layer prevents overheating of the polyurethane foam layer to in turn inhibit the formation of toxic fluids, which may condense upon the underside of the window to reduce the efficiency of the collector.

Abstract: A hydrophilic copolymer of N,N-(C.sub.1 -C.sub.2 alkyl) acrylamide is disclosed. The copolymer is formed by reacting, based on 100 parts, from 20-80 parts of the C.sub.1 -C.sub.2 alkyl substituted acrylamide, 80-20 parts of C.sub.1 -C.sub.4 alkyl acrylates, methacrylates, or combinations, and small amounts of a cross-linking agent. The resulting copolymerization product can be equilibrated with water or other aqueous solutions to form hydrogels useful in forming shaped hydrogel articles. One particular shaped article which can be formed is a hydrophilic contact lens. A process for forming the hydrogels is also disclosed.