Abstract: The method for the fabrication of a curved back projection screen includes coating the screen before forming a sheet into the proper curvature. In one embodiment the sheet includes lenticulations to improve the perceived luminous intensity thereof. Through this method a back projection screen is provided that overcomes the manufacturing difficulties associated with previously known methods.

Abstract: A minimum phase shift microwave attenuator circuit, providing very low insertion phase change with changing attenuation levels. Three PIN diodes are biased in parallel from a common node. The PIN diodes are held at zero or reverse bias for the "no attenuation" state, and are made slightly lossy to produce the attenuation state. In the attenuation state, the PIN diodes are utilized as current controlled lossy capacitors which change resistance with applied bias, but maintain constant capacitance, thereby providing low insertion phase deviation across wide attenuation levels.

Abstract: A weapon alerting and cueing system including a weapon terminal responsive to radar track information for radar detected aircraft; a first weapon launcher operated by a first weapon operator; a first weapon pointing sensor for providing azimuth and elevation information about the first weapon launcher; a first cueing sight for providing visual pointing cues to the first weapon operator; a first weapon cueing processor responsive to the radar track information, the weapon terminal, and the first pointing sensor for controlling the first cueing sight such that the first cueing sight provides visual cues for cueing the first weapon launcher to a selected radar detected aircraft target; a second weapon launcher operated by a second weapon operator; a second weapon pointing sensor for providing azimuth and elevation information about the second weapon launcher; a second cueing sight for providing visual pointing cues to the second weapon operator; a second weapon processor responsive to the radar track information

Abstract: A linear predictive ADC employs a fully feed forward design to extend its dynamic range, allow greater speed of operation, achieve stable operation and eliminate a requirement for sample-and-hold circuits. A first quantizer (Qc) converts an input analog signal to a digital format, while a signal predictor (32) predicts a subsequent value of the input signal. After conversion back to analog format, the predicted signal is compared with the actual subsequent value of the input signal to produce an error signal that is converted to a digital format by a second quantizer (Qf). The digital predicted signal is fed forward and combined with the digital error signal to produce a high precision digital output. The analog error signal is preferably amplified prior to digitation to take advantage of the full bit capacity of the second quanitzer (Qf), and then digitally de-amplified back to its original scale.

Abstract: An unregulated D.C. input voltage (V.sub.IN) is processed by a high power chopper (34,36) to produce a first chopped signal having the same voltage as the input (V.sub.IN), and by a low power chopper (56,58) to produce a second chopped signal in synchronism with and having a lower voltage than the first chopped signal. The first and second chopped signals are algebraically combined by transformers (52,54) to produce an A.C. output signal which may be converted to D.C. (V.sub.OUT). The second chopped signal may be controlled to have the same polarity relative to the first chopped signal in which case the voltages add to increase the output voltage (V.sub.OUT), or to have the opposite polarity relative to the first chopped signal in which case the voltages subtract to decrease the output voltage (V.sub.OUT). The periods of addition and subtraction are alternated within the period of the first chopped signal.

Abstract: Discrete solder preforms (28, 14a, 14b, 14c) are quickly and accurately placed on substrates (10) to be soldered by means of a foil sheet (24) apertured (26) with the pattern of preform placement. The foil sheet has a vacuum drawn through its apertures, and a number of discrete solder preforms are randomly projected from a vibratory membrane (38) up against the foil to be attached to the foil at each of its apertures. Then the foil sheet with its vacuum attached solder preforms (28, 14a, 14b, 14c) is moved into registration with the flux pattern (12a, 12b, 12c) pre-printed on the substrate (10), and all of the vacuum attached preforms are simultaneously positioned down upon the flux areas of the substrate where they remain when the vacuum is released. Planarity of the thin foil is maintained by a flat somewhat rigid but porous backing member (32) secured to the foil.

Abstract: An improved target assembly for a projection cathode ray tube is provided wherein the target member is protected from being inadvertently tilted, and thus the tube defocused when subjected to shock loading. The target member is supported by a shaft screw, which in turn is mounted on an adjustment pad for initially tilting the target member to focus the image. The positive locking elements includes external threads on the shaft screw received by inside threads of a center aperture in the adjustment pad. A locking nut is utilized to jam the shaft screw against the pad, and thereby load the cooperating threads. In addition, a threaded mounting stud of the target member engages internal threads of the shaft screw at the opposite end, and a locking set screw inside the shaft engages these internal threads and is tightened against the stud to load these threads.

Abstract: A far-red emitting phosphor for cathode ray tubes used in liquid crystal light valves comprises Y.sub.3-y Gd.sub.y Al.sub.5-x Ga.sub.x O.sub.12 :A, where x ranges from 0 to 5, y ranges from 0 to 3, and A is selected from the group consisting of chromium, iron, vanadium, neodymium, dysprosium, cobalt, nickel, titanium or combination thereof.

Abstract: A stainless steel mandrel (10) is etched with a negative pattern (16) of an electrical circuit that is to be made with the mandrel and then covered with Teflon (20) which is subsequently lapped to provide a coplanar surface of stainless steel and Teflon. A pattern of electrical conductors (30) is then electroformed, as by electrolytic or electroplating, on the exposed surfaces of the mandrel between the embedded Teflon. Surfaces of the electrical conductors of the circuit are then processed, as required for enhanced adhesion to a substrate, and a dielectric substrate of polyamide and acrylic is then laminated upon the surface of the mandrel over the electroformed conductors so that the dielectric substrate adheres to the conductors. The assembly of dielectric substrate and conductors is then separated from the planar surface of the mandrel and its embedded Teflon.

Abstract: Complimentary metal oxide silicon transistors fabricated on silicon-on-insulator substrates are configured to allow separately controllable and independent backgate bias for adjacent complimentary devices on the same substrate. By means of deep implantation of boron, a backgate bias P- well (26,126) is positioned on the N-substrate (17,117) at a front surface of the N- substrate behind the N channel transistor of a complimentary pair. The backgate bias P- well (26,126) is provided with an electrical contact (48,148) at the front of the device, as is the N- silicon substrate to enable independent application of separate bias voltage of different polarities and appropriate magnitude.

Abstract: A field emission device employs an anode in the form of an air bridge spanning the tip of a field emission cathode. The anode is supported only at its opposite ends, leaving the area under the air bridge open. An array of cathode emitters employ a series of parallel, laterally spaced anode air bridges, with each air bridge spanning a line of cathodes. The lateral spacing between the air bridges facilitates both the removal of underlying photo-resist during fabrication, and the establishment of a uniform vacuum if desired. The clearance between the anode and cathode is substantially less than previously obtainable, resulting in a significant reduction in both size and in the anode's operating voltage level. Fabrication of the air bridge anodes can be integrtaed with the remainder of an integrated circuit.

Abstract: An elastomeric member is incorporated between a conductor and a conductive interconnection bridge. This elastomeric member serves as a spring providing compliance to an interconnection so that the flatness requirements of an opposing mating structure may be relaxed. A flat metal mandrel is provided with an enlongated curved depression extending across a predetermined region where a resilient interconnection bridge is to be located. A nonconductive layer of Teflon is bonded to the surface of the mandrel. Grooves are ablated in a predetermined configuration down to the conductive surface of the mandrel using an excimer laser and a computer-controlled x-y table. Fineline electrical circuits are electrodeposited into the ablated grooves. The elongated curved depression is filled with a silicone material. The silicone material is permitted to cure to form a compliant elastomeric member having the shape of the elongated curved depression.

Abstract: A loudspeaker (34,134) excites a quarter wave resonant air column that is folded forward on itself. The column is closed at one end and has an output port located at the other. The output port (20,120) is in line with the speaker so that the one speaker can excite air both at the output port and at the closed end of the resonant column. At resonance, the column loads the speaker, and the speaker regeneratively drives the column output. At other frequencies output from the port is partially from vibration of the air column and partially from the speaker. At resonance the direct speaker output regeneratively reinforces and combines with the output of the resonant column, which has a length of one-quarter of the wavelength of sound propagated in air at the resonant frequency.

Abstract: A far-red emitting phosphor for cathode ray tubes used in liquid crystal light valves comprises lithium aluminum (or gallium) oxide, activated with iron or chromium. Increasing the activator concentration from 0.005 mole (commercially available) to about 0.015 to 0.05 mole increases the phosphor efficiency by about 50% and reduces the decay time from 30 msec (for the commerically available material) to 19 msec. Reducing the particle size to an average of 4 .mu.m or less provides the requisite high resolution for the CRT application.

Abstract: A traveling wave tube (10) includes a coupled cavity type slow wave structure (100) having a driver stage (52) and an output section (101) with a primary section (64) and a velocity taper section (82) which in combinattion produce maximum signal gain at a predetermined frequency. A gain flattening section (104) is preferably disposed between the driver stage (52) and the primary section (64) of the output section (101), and is designed to operate at a reduced phase velocity selected to produce minimum or negative signal gain at approximately the predetermined frequency. The gain characteristics of the driver stage (52), gain flattening section (104), primary section (64), and velocity taper section (82) combine to produce minimum signal gain variation over an operating frequency range which spans the predetermined frequency, and expand the bandwidth of the traveling wave tube (10).

Abstract: Two or more signal interaction structures (16,18), which may be klystron or traveling wave structures (32,50), are axially disposed in series between an electron gun (12) and a collector (14) for selectively velocity modulating an electron beam (20) generated by the gun (12) with a microwave input signal (IN1,IN2) and extracting a resulting amplified microwave output signal (OUT1,OUT2) from the beam (20). The interaction structures (16,18) are designed to operate in different frequency bands, for example the X and Ku bands, with only one of the structures (16,18) having an input signal (IN1,IN2) applied thereto at any given time. The interaction structures (16,18) are further designed such that the structures (16,18) which are not being used do not affect the structure (16,18) which is being used.

Abstract: A pressure type contact (10) for flexible or conventional wire cable terminations is fabricated from electroformed thin metallic wafers in which one wafer is plated with a raised conductive interconnection feature. The raised feature is formed by placing a small lump (44) of electrically conductive resin on a substrate (12) and then electrolytically forming on the substrate a trace (18) having an enlarged connector pad (20) that completely covers the cured projecting resin lump.

Abstract: A gallium arsenide monolithic microwave integrated circuit (MMIC) chip (12) has microelectronic devices (16,18) formed on a frontside surface (12a), and via holes (12c,12d) formed through the chip (12) from the frontside surface (12a) to the backside surface (12b). The backside surface (12b) of the chip (12) is bonded to a molybdenum carrier (14) by an eutectic gold/tin alloy (20). A barrier layer (22) including a refractory metal nitride material (22a) is sputtered onto the backside surface (12b) and into the via holes (12c,12d) of the chip (12) prior to bonding. The barrier layer (22) blocks migration of tin from the eutectic gold/tin alloy (20) through the via holes 12c,-12d) to the frontside surface (12a) of the chip (12) during the bonding operation, thereby preventing migrated tin from adversely affecting the microelectronic devices (16,18 ).

Abstract: Interconnection of densely populated multiple chip integrated hybrid circuits (12) in a manner such that heat can be efficiently extracted therefrom. An integrated circuit die (31) is attached to a flip chip interconnect layer by soldering the connection pads thereto. The interconnect layer is slid off its substrate (11) in the manner of a decal. After the circuit has been tested and found acceptable, the other side of the die (31) is permanently bonded to a thermal conduction plate or heat sink (32). The decal interconnect (33) is made of alternating layers of an insulator (41) and a conductor (42) built on top of an erodible sacrifical layer (48) applied to a substrate. The sacrificial layer (48) is dissolved by a suitable solvent to float the multilayer interconnect off the substrate (11).

Abstract: A reflow solder head has its heater bar (30) mounted so as to cause the heater bar to contact a tilted reflow surface (50) and align itself with the tilted surface without tip skid. The heater bar is mounted to its movable drive ram (40) by two independent pivots (36,42), both nominally positioned on a line normal to and in the center of the heater bar itself. The first pivot (36) closer to the heater bar allows the heater bar to rotate about its first point of contact (54) with the tilted reflow surface. The second pivot (42) allows lateral movement of the first pivot (36) without tip skid during the rotation of the heater bar about its first point of contact. This double pivot mechanism eliminates the tendency of the heater bar to skid along the reflow surface.