Abstract: A cleanroom facility is provided with an air shower in which gasper jets are used to direct air in a preferred manner against persons entering the cleanroom facility. The gasper jets are combined with a downward air flow and with air curtains which limit the escape of dust particles from the air shower to remaining portions of the cleanroom facility. Primary and secondary air showers are provided to first remove excess particles from the person's street clothes, and then remove any loose particles which may be on the person's cleanroom clothing. A third air shower is provided as a separate secondary air shower for a second cleanroom facility area.

Abstract: A semiconductor package having a gull-wing, zig-zag, inline-lead configuration and end-of-package anchoring devices for rigidly affixing the package to a circuit board such that each lead is in compressibe contact with its associated mounting pad on the board. The anchoring devices of a first embodiment comprise anchoring pins having fish-hook-type barbs which lock against the under side of the board when the pegs are inserted through holes in the board; a second embodiment utilizes anchoring pins which are adhesively bonded in recesses that have been drilled or molded into the board; a third embodiment utilizes anchoring pins, the ends of which can be bonded directly to planar peg-bonding regions on the surface of the board; and a fourth utilizes tapered anchoring ping which may be inserted with an interference fit into holes in the board. The invention eliminates the need for mechanical support of the packages during solder reflow operations used during board assembly and repair.

Abstract: An underhood includes a helmet portion and a mask portion. The helmet portion consists of a loosely fitted bonnet which is attached to an elastic lower section. The elastic fabric (two-way stretch) substantially surrounds the bottom of the headdress in the manner of a headband, but is open below that location. A face mask secures the lower section around the user's face. The face mask is made of highly breathable fabric and relies on the elasticity of the stretch fabric in the lower part of the helmet portion for elastic fit around the user's face. Therefore, the face mask is relatively inelastic, while permitting elastic fit around the face.

Abstract: A voltage level conversion circuit which may be used on CMOS integrated circuit semiconductor devices uses a regulated power supply to drive an internal array and periphery logic. The voltage converter includes a first inverter (31), an isolating transistor (Q3), and an output inverter (35). An isolating transistor (Q3) admits current to the output inverter (35) until the output inverter (35) switches its output level. An active biasing circuit, including transistor Q4, causes inverter (35) to remain at a low state after the isolating transistor (Q3) gates off, thereby allowing the output inverter to continue to provide its output in isolation from the first inverter's output voltage.

Abstract: An improved interdigitized leadframe strip having a pair of rail stubs coextensive with the exposed pins of the leadframes at either end of the strip, which can still be stamped from a continuous strip without any waste of material between the individual strips. The split rail stubs are still considerably wider than the exposed pins of the end leadframes and hence, offer considerable protection to the exposed pins from mechanical damage.

Abstract: A method and apparatus for feeding preform wire into a preform dispenser, cutting a piece of preform, transferring the preform to a location over an integrated circuit ceramic package, and placing the preform in the package prior to placing and attaching a die in the ceramic package.

Abstract: A holder for positioning silicon wafers on a microscope stage for uniform and repeatable viewing under the microscope. The holder comprises a circumferential rib having an arc of from about 60.degree.-180.degree. diametrically opposed to a radially aligned slit within which a bracket member is positioned. Actuation of the bracket member pushes against a major flat on the silicon wafer, causing the leading edge of the wafer to bear against the abutment. The holder, or platen, is provided with calibration standards on a circumferential edge portion, and is also provided with at least one access port permitting access to the underside of the wafer with vacuum wands.

Abstract: A circuit having both p-channel and n-channel transistors is made programmable by providing the p-channel transistor with a floating gate which is in electrical continuity with a floating gate which is in electrical continuity with a floating gate on the n-channel transistor. In order to compensate for over-deprogramming, the circuit includes transistor which shunt the programmable transistors when the transistors are over-deprogrammed.

Abstract: A voltage sensing circuit is used to rapidly pull up a high potential node of a reference array to a value of a high potential source reduced by a threshold voltage (V.sub.CC -V.sub.T). During an enable cycle, the high potential node is precharged to a potential of V.sub.CC -V.sub.T, which turns on a transistor gated to the V.sub.CC potential. This pulls the high potential node as rapidly as possible to a high level in order to speed up the sensing process. A potential maintenance circuit provides sufficient current from the high potential source to maintain a desired potential at the high potential node.

Abstract: A memory array (e.g., DRAM) is provided with a potential maintenance circuit which provides sufficient current to maintain a high potential node of the memory array at a predetermined potential. The potential maintenance circuit is gated ON after receipt of a clock signal and gated OFF at the predetermined potential. This permits the high voltage node to be maintained, while reducing current requirements. The invention is particularly useful when used in conjunction with a circuit which rapidly pulls up the high node to a value of V.sub.CC -V.sub.T (where VT is a threshold voltage of a transistor).

Abstract: A reusable burn-in/test fixture for discrete TAB die consists of two halves. The first half of the test fixture is a die cavity plate for receiving semiconductor dice, and contains cavities in which die are inserted. The second half establishes electrical contact with the dice and with a burn-in oven. The test fixture need not be opened until the burn-in and electrical test are completed. After burn-in stress and electrical test, the die are removed from the test fixture and depositioned accordingly. The technique will allow all elements of the burn-in/test fixture to 100% reusable.

Abstract: A decoupling capacitor system for improving the reliability of digital logic circuit boards such as single inline memory modules which use surface-mount decoupling capacitors. The system comprises one or more units of two or more series-connected capacitors connected between the chip supply voltage (Vcc) input and the chip ground (Vss) connection. Given no change in the reliability of the individual capacitors, the reliability of a circuit board can typically be improved by several order of magnitude.

Abstract: A direct current (DC) powered gyroscope (41) utilizes an alternating current (AC) subsystem in which electrolytic switches (49, 50) control torquer motors (45, 46). The alternating current is obtained from commutation circuitry (21-23) in the gyroscope spin motor, so that the spin motor performs an inverter function. Advantages include reduced costs and the ability to operate the gyroscope (41) without an AC power supply.

Abstract: A gas gyroscope 11 is provided with an aspirator pump 71 in order to evacuate gas from the main chamber 19 of the gyroscope 11. The evacuation of gas reduces windage and other air friction encountered by the gyroscope's rotor 21 and thereby extends the rundown time of the gyroscope. The aspirator 71 may be energized by a dedicated compressed gas source such as a compressed gas chamber 91. Alternatively, the aspirator 71 may be provided with ram air or bleed perpellant gases.

Abstract: Liquid bearing two degree of freedom inertial sensor apparatus is disclosed. A single liquid bearing sensor is configured in a two degree of freedom rate gyro mode, or two of the liquid bearing sensors are made pendulous along their spin axes and configured in a two degree of freedom rate gyro and accelerometer mode.

Abstract: Apparatus is disclosed which is controlled via computer interface logic for converting digital signals corresponding to predetermined synchro/resolver shaft angles into analog signals for stimulus purposes, and for converting the analog signals into digital words for measurement purposes. External synchro/resolver shaft angle signals may be converted into digital words for like purposes. The apparatus has a plurality of converter channels, each of which is controlled by the computer interface logic for operation independent of the other channels. The apparatus so configured is particularly adaptable for providing stimuli and measurements which are useful in test systems applications.

Abstract: A shaft assembly (11) having a spline (16) with an anti-backlash device operable due to centrifugal force to engage both sides of internal spline teeth during rotation. The spline (16) includes a main force transmitting portion (18) and a moveable spline sleeve (22) which during operation engages the side of teeth opposite the side engaged by the main force transmitting spline. Spline sleeve (22) rides on helix member to move slightly circumferentially as it is moved axially by a centrifugal force actuated member. A bar which is pinned to the spline (16) has one end which moves radially outward due to centrifugal force as the spline (16) is rotated and another end which engages and moves the spline sleeve (22) axially. When the spline sleeve (22) is moved, the splined end on the shaft assembly (11) is locked or wedged into engagement with the mating internal spline (14).

Abstract: Gyrocompassing apparatus for stationary equipment is disclosed which provides heading and two-axis tilt information while utilizing a minimum complement of relatively low cost components. The apparatus features a single degree of freedom gyroscope mounted to a mechanical levelling and indexing arrangement for implementing a gyrocompassing routine. Tilt information is provided with relatively high accuracy via a two-axis pendulum mechanization. A microprocessor with associated peripherals provides required control, compensation and computational functions.

Abstract: A serial to parallel bus converter (11) enables a slave computer (13), having a parallel bus input (19) to be controlled by a master computer (15) via a serial bus connection (14). The converter (11) interprets commands from the master computer (15) to provide appropriate control commands for the slave computer (13). Instructions received from the master computer (15) are provided to the slave computer (13) when complete commands from the master computer (15) are received by the converter (11). The converter (11) uses an intermediate bus (29), which is connected to the RAMs (27), ports (41-44) and a control register (45) for communicating with the slave computer (13), a UART port (31) for communicating with the master computer (15), a microprocessor (25) and a programmable read only memory (PROM) (33) for the microprocessor (25).

Abstract: An electronic device, such as a bubble memory (21), which has a narrow temperature band of operation, is maintained within the narrow temperature band by a Peltier circuit (30). The Peltier circuit (30) includes a Peltier junction (31) which is placed in a heat conducting relationship with the bubble memory (21). The Peltier circuit (30) has the advantage of being able to alternately heat or chill the bubble memory device (21) in order to maintain the bubble memory device (21) within its recommended temperature range.