Abstract: A photopolymerizable composition includes a water-insoluble olefinic compound that is polymerizable with free-radical initiators, an oil-soluble phenothiazine dye that is soluble in water-immiscible organic solvents, and a reducing agent operable to react with the dye to form reactive free radicals only when the dye is in an excited state induced by exposure to light. The reducing agent and the dye are reacted together under the influence of light, and particularly red light. The resulting reactive free radicals cause the olefinic compound to polymerize to a polymer that is substantially unaffected by the presence of moisture.

Abstract: A new type of semiconductor material is disclosed which consists of a .beta.-SiC:metal carbide alloy having the general formula Si.sub.w (metal 1).sub.x (metal 2).sub.y (metal 3).sub.z C, where w+x+y+z=1 and 1>w>0. The metals are selected from the group consisting of Ti, Hf, Zr, V, Ta, Mo, W and Nb, with Ti, Hf, and Zr preferred. By selecting appropriate proportions of metal carbide and SiC, the alloy's bandgap may be tailored to any desired level between the bandgaps of the metal carbide and SiC. Semiconductor devices are preferably formed by epitaxially growing a layer of the new alloy upon a substrate having a .beta.-SiC or TiC type crystal structure. In addition to retaining the benefits of single-bandgap .beta.-SiC with certain advantages, the new alloys make it possible to implement various electrical devices that cannot be achieved with .beta.-SiC, and also have a potential for bandfolded superlattices for infrared detectors and lasers.

Abstract: A superconducting oxide precursor material is prepared by dissolving soluble compounds containing the non-oxygen elements of the oxide in concentrated nitric acid, in which a decomposing agent for the nitrate of the nitric acid selected from urea and sucrose and an oxidizing/reducing agent selected from hydrogen peroxide and ammonium nitrate have also been dissolved. The acid solution is concentrated by heating until the liquid component is pyrolyzed, leaving a superconducting oxide precursor material residue. The precursor material is produced with a relatively high oxidation state, but is normally further oxidized to reach a superconducting state.

Abstract: A molecular beam epitaxy (MBE) growth method and apparatus is disclosed which achieves a significantly improved sticking coefficient for materials like Hg upon a substrate, and thus a higher efficiency. A highly ionized, low pressure plasma is formed consisting of a mixture of ions of one substance of a compound to be epitaxially grown, neutral particles of the substance and electrons, and also preferably both ionization and excitation radiation. The plasma is directed onto a substrate together with a flux of the other substance in the compound; the flux can be in the form of either a vapor, or a second plasma. Radiation assisted epitaxial growth for Hg compounds in which ionization and excitation radiation are formed from Hg vapor and used to assist epitaxial growth with neutral Hg particles is also described. The plasma is formed in a special discharge chamber having a hollow cathode with an emissive-mix-free cathode insert.

Abstract: A precision sigma-delta A/D converter having a desired number of cascaded stages is disclosed herein. The multi-stage sigma-delta analog-to-digital converter (10) of the present invention is operative to convert an analog input signal X(z) to an output sequence of digital words. The converter (10) of the present invention includes a first sigma-delta converter stage (14) for generating a first sequence of digital words and a quantization error signal in response to the analog input signal X(z). An interstage amplifier (34) then amplifies the quantization error signal by a first gain factor G. The present invention further includes a second sigma-delta converter stage (18) for generating a second sequence of digital words in response to the amplified quantization error signal. The first and second sequences are next filtered by a digital noise cancellation network (31, 32) and the filtered second sequence is divided by the first gain factor G via a divider circuit (38).

Abstract: An optically phased conformal antenna and photonic interconnect therefor that may be used in such microwave systems. Rows of microwave circuits are disposed on top of a cooling arrangement disposed on a curved surface. An optical ribbon cable disposed on top of the microwave circuits is employed to couple signals to the microwave circuits. Microwave antennas are disposed on top of the optical ribbon cable which has windows therein that permit welding of the antennas to the appropriate microwave circuits. Optical coupling of signals from the optical cable to the microwave circuits is achieved through the use of diffraction gratings, and the like, formed in the optical cable, in conjunction with laser diodes and detectors disposed on the chips.

Abstract: A miniature electrostatically actuated switch and process for fabricating it in which the switch is operable to connect and disconnect one or more transmission lines laid down on a dielectric substrate of an integrated circuit wafer. The switch is fabricated on the integrated circuit wafer using integrated circuit fabrication processes including thin films of conductive materials and photoresist and selective removal of these films. the switch includes a rotating switch blade which rotates about a hub formed on the dielectric substrate under the influence of electrostatic fields created by control pads and other switch elements formed on the dielectric substrate, whereupon a microwave signal can be switchably transmitted along the transmission line formed on the substrate.

Abstract: A signal generator 16 is disclosed. The invention is adapted for use with industrial positioning systems and includes an integrating circuit 22 for integrating an input error signal to provide an output error signal and a limiting circuit 24, connected between the input and output of the integrating circuit 22 for limiting the output error signal. The output error signal is then used in a conventional manner to control a work piece or an implement. The integration of the low level input error signal rapidly increases the power delivered to the positioning system to overcome initial static friction. When the amplitude of the error signal indicates that the industrial apparatus is within a predetermined tolerance, the amplitude of output error signal decreases exponentially to diminish rapidly the power delivered to the positioning system. The apparatus will therefore be positioned within a given tolerance range.

Abstract: A solid electrolyte ion source has an emitting tip which is small enough to concentrate an elecric field from an extraction plate and thereby significantly increase the extracted current density compared to prior solid electrolyte sources. The source is heated to a temperature sufficient to induce a thermionic ion emission from the tip. The ion emission can be varied independent of the extraction field by varying the degree of heating, thereby preserving a constant focused ion beam spot size during changes of beam brightness. The tip preferably has a radius in the approximate range of 1-10 microns. The source can be used for ion-microprobe surface analysis and micro-circuit fabrication applications previously unavailable with solid electrolyte sources.

Abstract: A high voltage stable pulse power supply 10 which includes a first power supply 11, ; a first capacitor 12 ; connected in parallel with the first power supply, a first switch 13 mounted in parallel with the first capacitor 12. The switch 13 selectively connects the first capacitor 12 to a load 14 so that the first capacitor 12 may discharge therethrough. An anti-droop network 15 is connected in series with the first capacitor 12. The anti-droop network 15 cancels droop in the output of the first capacitor 12 as it discharges into the load 14.In a specific embodiment, the anti-droop network 15 includes an inductive element 42 connected in series with the first capacitor 12 which is charged just prior to the activation of the first switch 13. The inductor 42 provides energy to compensate for the droop in the energy supplied by the first capacitor 12.

Abstract: A light emitting panel is formed of a transparent plastic substrate doped with fluorescent dye which absorbs incident light through a relatively large surface area and emits light of a longer wavelength out through one edge. The incident light may be ambient or produced by a fluorescent light source. The edge emitted light is optically coupled into an edge of a display panel, which may be a polymer dispersed liquid crystal display or a plastic panel having a display surface formed with an etched or printed pattern, grating or hologram. The substrate materials of the emitting and display panels, as well as an optical adhesive which joins the edges thereof, preferably have an essentially similar index of refraction which is larger than that of air causing light propagating through the panels to be internally reflected and exit the structure only through the pattern on the display surface.

Abstract: A photodetector produces an output signal in response to irradiation by an optical beam from a pulsed laser. A delay unit delays the output signal for a period corresponding to one-half of one cycle of a beat frequency generated by interaction of two frequency components in the optical beam corresponding to two predetermined longitudinal modes of operation of the laser. A differential mixer subtractively combines the output of the photodetector with the output of the delay unit, to produce an output signal having the main profile of the laser pulses suppressed, and the beat frequency component, if present, amplified. A resonant circuit and amplifier may be provided to further amplify the beat frequency component. The output of the amplifier is integrated to produce a DC signal having a magnitude which corresponds to the amplitude of the beat frequency component. The DC signal is compared with a threshold value to discriminate between single and multimode operation of the laser.

Abstract: A plasma wave tube and associated operating method are described in which a pair of cold-cathode electron beam generators discharge counterpropagating electron beams into an ionizable gas, preferably hydrogen or a noble gas, within a waveguide housing. A voltage within the approximate range of 4-20 kV relative to the waveguide housing is applied to the cathodes to produce electron beams with current densities of at least about 1 amp/cm.sup.2. The beams form a plasma within the gas and couple with the plasma to produce electron plasma waves, which are non-linearly coupled to radiate electromagnetic energy in the microwave to mm-wave region. A magnetic field is established within the waveguide between the cathodes to confine the plasma, and to control the beam discharge impedance. The gas pressure is held within the approximate range of 1-100 mTorr, preferably about 10-30 mTorr, to damp plasma instabilities and sustain the beam voltages, while the magnetic field is within the approximate range of 100-500 Gauss.

Abstract: A spatial light modulator includes a photosensor diode and a photoemitting diode array, each having two semiconductive layers of opposite electrical polarities, and which are sandwiched together with layers of the same polarity (P or N) in electrical contact with each other. Transparent electrode layers are formed on the opposite surfaces of the photosensor diode and photoemitting diode array respectively, in electrical contact with the layers of the opposite polarity. The individual photoemitting diodes are electrically and optically isolated from each other. With a voltage applied across the electrodes which causes the photosensor diode to be reverse biased and the photoemitting diodes to be forward biased, the photoemitting diode array generates a visual display which is a reproduction of a light image incident on the photosensor diode. The photosensor diode may be replaced by a single layer of a photoconductive material.

Abstract: A plasma generator 10 which includes an rf driven cathode 40 capable of using reactive gases and having a cathode housing 54. A gas feed system 20 introduces gas into an antechamber 42 defined by the cathode housing 54. An electric field is generated within the antechamber 42 by an antenna 46. A grid 50 mounted within the antechamber 42 defines first R1 and second R2 regions therein, a first region R1 between the antenna 46 and the grid 50, and a second region R2. The grid 50 confines the electric field generated by the antenna 46 to the first region R1 of the antechamber 42 to induce a discharge of electrons from the gas therein. The grid 50 further allows at least a portion of the discharged electrons to migrate to the second region R2 to ionize the gas therein into a cathode plasma 60. In one embodiment, the plasma 60 is then induced to flow into a discharge chamber 70 defined by an anode shell 72.

Abstract: Disclosed herein is an arrangement for shielding individual electronic units from undesired microwave or millimeter wave radiation while providing a means of transferring input and output signals and operating power through the shield wall. A metal box encapsulates an electronic unit. Input and output signals are fed into and transferred from the electronics unit through the shield wall using optical links and photo transmitting and receiving components. Power is transferred through the shield box wall using piezo crystals secured to the outside and inside of the shield box wall and a dielectric rod connected between the two piezo crystals through a hole in the wall. Electrical energy therefore can be transferred into mechanical energy transferred through the box wall to the piezo crystal within where it is received and transferred back into electrical energy. Accordingly, metal feedthroughs are not needed, eliminating any paths for radiation to enter the shield box.

Abstract: A reflective matrix mirror visible to infrared converter light valve (5) includes a liquid crystal medium (60) for spatially modulating an incident infrared beam by polarization rotation, a photosubstrate (30) for receiving an incident visible wavelength image (115) and for controlling the polarization rotation of the liquid crystal medium (60) responsively to the visible image (115), and a reflective matrix mirror (40). The reflective matrix mirror (40) is positioned between the liquid crystal medium (60) and the photosubstrate (30) and reflects the incident infrared beam (125) back through the liquid crystal medium (60) such that the infrared beam (125) passes through the liquid crystal medium twice and is polarization rotated responsively to the visible wavelength image (115). A polarizer (90) positioned exteriorly of the liquid crystal medium (60) converts the polarization rotation of the infrared beam (125) into output intensity modulation to produce an infrared image (130).

Abstract: An orientation independent ignitron (OII) has an anode, a cathode with a plurality of spaced grooves facing the anode, and a cooling mechanism which causes liquid metal vapor to condense as a film which is retained on the grooved cathode surface by surface tension and forms reservoirs within the grooves. The cathode and anode are preferably cylindrical and coaxial, with the inner surface of the cathode having parallel annular grooves facing the outer anode surface. Igniters are preferably introduced into convex areas between adjacent grooves along radial lines, with individual igniters providing ignition for a pair of adjacent grooves. The igniters can be operated simultaneously or in sequence, depending upon the desired repetition rate and current capacity. A liquid metal film is initially formed by placing the OII on its side, introducing liquid metal into the lower ends of the grooves, and causing arcing between the anode and liquid metal to flow the liquid metal and wet the adjacent groove surface.

Abstract: An array of processing element nodes are provided on a semiconductor wafer. A mixed redundancy approach is preferably employed wherein two spare core logic circuit modules 52, 58 are available for use at each node. Each spare core logic module can be connected to one of four different nodes. An H-net 94 interconnects adjacent nodes in such manner that faults in the circuit modules can be easily tested and repaired.

Abstract: An apparatus for maintaining a crystal at a precisely controlled operating temperature over extended periods of time without significant thermal degradation of the crystal. The apparatus has thermally conducting walls. The walls define an inner hermetically sealed chamber for the crystal. Input and output windows are hermetically sealed to the input and output ends of the chamber. The inner surfaces of these windows are maintained at the operating temperature of the crystal to prevent fogging of the windows. Flexible thermal conducting layers are used between the crystal surfaces and the walls of the chamber to achieve uniform and continuous thermal contact therebetween, without mechanical stress to the crystal. The structure provides fast thermal response, controlled temperature in the crystal interaction region and stability of operation over extended periods of time. In one preferred embodiment, the crystal is held in suspended position within the chamber between a pair of spring-loaded plungers.