Abstract: In a slab laser, the optical pumping lamps extend transversely to the mean direction of the laser beam with the spatial period of the lamps being harmonically related to the spatial period of the zig-zag laser beam path within the slab, preferably with equal periods. In addition, the lamps are preferably positioned in registration over the lines of intersection of the central ray of the laser beam with respective broad face of the laser slab. A planar flashlamp reflector is employed for economy of fabrication. Directional lamp reflectors are employed for increasing laser efficiency and performance by discriminating against amplified surface waves.

Abstract: A thermally insulative buoyant swimming pool cover floats on the surface of the pool for covering the pool and for retaining the heat within the pool. Sinking means, such as weights or a mechanical pull-down structure, may be secured to the pool cover along certain predetermined action lines such as fold lines. In one embodiment, an inflatable and deflatable bladder is coupled to the weights. The bladder is dimensioned relative to the weights such that when inflated it overcomes the negative buoyancy of the weights to retain the pool cover in the fully covered position. However, when the bladder is deflated, the weights overcome the positive buoyancy of the cover along the certain fold lines causing the cover to be at least partially pulled below the surface of the pool and folded while at the same time being retracted against one of the side walls of the pool. Pool water is circulated over or through channels of the pool cover to provide solar heating.

Abstract: An etch stopped layer portion overlying a (100) or (110) major face of a diamond cubic semiconductor material is undercut anisotropically etched by orienting a side edge of the etch stopped layer portion which is to be undercut, at an angle to the most nearly parallel {111} trace on the (100) or (110) face. The etch time is further reduced by slotting through the etch stopped layer with slots oriented at an angle to the {111} traces on the underlying (100) or (110) face. Undercut bridge structures are formed by undercutting quadrilateral etch stopped layer portions from opposite sides of the quadrilateral or from the sides plus slots forming diagonals of {111} trace quadrilaterals having combined areas coextensive with the area to be undercut.

Abstract: Three dimensional single crystalline structures, such as folded cantilever beams supported from a frame and supporting a central structure free to move relative to the frame, are fabricated by anisotropically etching through openings in etch stop layers on opposite sides of the substrate wafer. The openings are patterned and aligned so that the etch stop layers are undercut to define etch stop portions interconnected by unetched substrate material.

Abstract: In an automatic wafer prober, the prober steps through a certain predetermined sequence of die on the wafer. After a certain predetermined number of die have been probed, the prober automatically interrupts the probing sequence and steps the prober off of the wafer onto an abrasive element for scrubbing clean the probe tips. Thereafter, the prober returns to its predetermined probing sequence. The abrasive element is preferably fixidly secured to the wafer chuck. A flat of the abrasive element serves as an alignment flat for registration with a flat of the wafer.

Abstract: In a miniature valve, a valve seat is formed by aperturing a plate. A cantilever leaf spring is disposed overlying the apertured plate for controlling the flow of fluid therethrough. An electrostatic potential applied between the cantilever leaf spring and the valve plate pulls the leaf spring over the apertured plate for variably controlling flow through the valve in accordance with the magnitude of the applied potential. In a preferred embodiment, the cantilever leaf springs are made in batch form by etching a silicon wafer. A flow controller is provided by measuring the electrical capacitance of the valve, comparing it with a reference voltage and deriving a feedback voltage applied to the valve for controlling flow therethrough. In one embodiment, the width of the cantilever leaf spring valve member is narrowed toward its free end for finer control of flow.

Abstract: Displacement of a movable transducer element is measured by exciting a capacitive gap (preferably differential capacitive gaps) with triangular waves of voltage to obtain a square current wave output into a zero input impedance amplifier. The square wave output is amplified and synchronously detected to produce a d.c. output signal proportional to displacement. The d.c. output signal is fed back to force rebalance electrodes to electrostatically rebalance the movable transducer element. The feedback signal is a measure of the force being transduced. Initial offsets in the position of the transducer element and capacitances of the capacitive gaps are compensated by signals derived from the capacitive gap excitation waveforms.

Abstract: In a high average power slab laser, heat generated in the laser slab is conducted through a thin layer of thermally conductive gas, such as hydrogen, helium or air, and then through an optically transparent window into a flow of liquid coolant. In a preferred embodiment, a second flow of liquid coolant is employed for cooling of the pumping lamps such lamp liquid coolant flow being partitioned from the slab liquid coolant flow by means of an optically transparent partition through which the pump radiation is directed from the lamps to the slab. In another embodiment, the slab coolant flow is controlled so as to operate the laser slab in a self-annealing temperature regime, whereby thermal stresses are annealed out in use and higher average output beam power is obtained.

Abstract: A kilowatt average power solid state laser employs a reciprocating slab of Nd:glass to effectively average the thermal loading thereof.

Abstract: A magnetic rotator lens for rotating the momenta of particles transverse to the direction of the beam is disclosed. The rotator lens includes a solenoid axially aligned with the beam and employs a magnetic permeable flux return structure surrounding the solenoid. The flux return structure includes beam entrance and exit plates with magnetic permeable and charged particle permeable portions forming the beam entrance and exit ports of the magnetic lens. In a typical example, the beam entrance magnetic permeable and beam permeable portion of the pole piece structure is formed by a grid of magnetic permeable members. The magnetic permeable and beam permeable portions of the pole structures terminate the axial magnetic field without introducing any substantial transverse components to the magnetic field which would otherwise produce undesired rotation of the beam shape.

Abstract: A sputter coating machine includes a rectilinearly translatable load-lock door closing off one end of an evacuable chamber. Wafers to be coated are loaded and unloaded by an elevator blade onto a chuck carried from the inside surface of the door. A clamping ring clamps the wafer to the chuck and advances the wafer through the open throat of a gate-valve portion of the chamber into position opposite a magnetron sputter gun carried from a second door closing off the other end of the chamber. The second door is movable away from the chamber on guide rails and pivotable about an axis for ease of maintenance.

Abstract: A sputter coating machine (11) includes a rectilinearly translatable load-lock door (16) closing off one end of a vacuumable chamber (12). Wafers (21) to be coated are loaded and unloaded by an elevated blade (24) onto a chuck (57) carried from the inside surface of the door (16). A clamping ring (85) clamps the wafer (21) to the chuck (57) and advances the wafer (21) to the open throat of a gate-valve portion (15) of the chamber (12) into position opposite a magnetron-sputter gun (105) carried from a second door end of the chamber (12). The second door (13) is moveable away from the chamber (12) on guide rails (141) and pivotable about an axis (138) for ease of maintenance.

Abstract: An automatic wafer prober is interfaced with any one of a number of different die testers by storing in memory associated with the wafer prober a plurality of sets of data there being one set of data for each of a plurality of different die testers to be interfaced to the prober. Each set of data defines at least the sense (polarity) of a plurality of test result output signals derived from the particular die tester to be interfaced with the prober. The proper set of stored data is selected by the operator, such as by a digital switch, and a microprocessor employs the selected set of data for modifying the sense of the test result output signals derived from the die tester as fed into the wafer prober so that the die tester output signals as fed into the wafer prober are the same for any one of the plurality of different die tester. In a preferred embodiment, the microprocessor generates a test start signal which is outputted from the prober to the die tester.

Abstract: Semiconductive wafers are processed, i.e., etched or layers deposited thereon, by means of a plasma enhanced chemical vapor processing system wherein the plasma is generated by a train of R.F. power pulses. The pulse repetition rate, pulse length and peak power level of the individual pulses are independently variably controlled to variably control the uniformity of the processing of the semiconductive wafers within the processing gaps.

Abstract: In an extraction method and apparatus for extracting low biomass solid materials from a pneumatic transport line, the stream of gas having the solids entrained therein is caused to flow over a toothed extractor wheel. The toothed wheel picks out of the stream the solid materials which are then doffed from the tooth extractor wheel by the vanes of a rotating valve which seals the pressure of the pneumatic transport line from the ambient. The material doffed from the extractor wheel falls into the region between the vanes of the rotary valve and is then removed from the system as the vanes of the valve rotate. The air stream which is inducted into the extractor is first caused to pass through a diffuser which slows the velocity of the air stream and then the air stream is cause to flow along a curved duct section toward the extractor wheel causing the solid materials to flow to the outside of the curved duct section and into the extractor wheel to facilitate extraction.

Abstract: An electromechanical braille cell is disclosed wherein each cell includes six braille indicia formed by the free ends of six rods protruding through six openings in braille reading surface. The six rods are raised and lowered by six piezoelectric reeds. Applying an operating potential to a respective reed causes the reed to bend about a fulcrum at the supported root end of the reed causing the free end to deflect in such a manner as to cause the indicia rod to be raised and to protrude through an opening in the reading surface of the braille cell. Simultaneous energization of one or more of the six reeds defines a given braille character sensed by the braille reader. Modulating the voltage applied to a given reed serves to vibrate the respective rod for sensing by the braille reader for indicating information, such as upper case, to the reader in addition to the braille character information represented by merely elevating a pattern of rods above the braille reading surface.

Abstract: A memory tester is disclosed for testing a matrix of memory elements, such matrix having spare rows and columns of memory elements to be used for repair of the memory under test. The memory tester tests the memory matrix under address control of a programmable pattern generator to derive failure data and stores the failure data in corresponding rows and columns in a second memory matrix. Failure data in the second memory is scanned by an error analysis circuit, under control of the pattern generator, first by row and when the number of failures in any row exceed the number of spare columns that row is flagged for replacement. Next, the columns of failure data are scanned and when the number of failures in any column exceeds the number of spare rows, that column is flagged for replacement. During the scan of the columns, previously flagged rows are masked such that failures which are to be repaired are not counted.

Abstract: A memory tester is disclosed for testing a matrix of memory elements, such matrix having spare rows and columns of memory elements to be used for repair of the memory under test. The memory tester tests the memory matrix to derive failure data and stores the failure data in corresponding rows and columns in a second memory matrix. Failure data in the second memory is scanned first by row and when the number of failures in any row exceeds the number of spare columns that row is flagged for replacement. Next, the columns of failure data are scanned and when the number of failures in any column exceeds the number of spare rows, that column is flagged for replacement. During the scan of the columns, previously flagged rows are masked such that failures which are to be repaired are not counted.

Abstract: In an X-Y addressable workpiece positioner, the workpiece to be positioned, such as a semiconductive wafer to be sequentially exposed at different regions thereof in accordance with a pattern of a mask, is disposed for movement with a work stage along coordinate X and Y axes. The work stage has a two-dimensional array of X and Y coordinate addressing indicia enclosed within a border and affixed to the work stage for movement therewith. A portion of an enlarged image of the array of addressing indicia is projected onto a sensor stage to derive an output indicative of the X and Y coordinates of the array of addressing indicia relative to the position of the sensor stage. The X and Y coordinates of the array of addressing indicia are sensed through addressing indicia recognition windows of the sensor stage and are differentially compared to remove unwanted background effects.

Abstract: A field effect liquid crystal display is disclosed wherein an composite alternating voltage is successively produced across a matrix of pixels formed by crossed arrays of row and column electrodes of the display. The composite alternating voltage consists of a row driving alternating voltage component and a column driving alternating component voltage. The phases of the row and column alternating voltage components are relatively phased so as to produce the composite alternating voltage across the individual pixels. The column alternating voltage component includes a gray scale component having an (root mean square) RMS value variable in accordance with the gray scale of the image to be displayed on the liquid crystal display. Two systems are disclosed for deriving the composite RMS voltage having the gray scale component.