Abstract: A method is disclosed for the visual inspection of electrical circuitry deposited in the layers of a multilayer printed circuit board wherein the dielectric layers of the multilayer board are prepared using a clear, light transparent thermosetting resin having incorporated therein a dye which is permeable to visible light but which absorbs light in the 320-440 nm region.The electrical circuitry in the board can be easily traced by an observer upon illumination of the board by visible light.

Abstract: A banking machine having a single opening for both envelope and individual check or note deposit is disclosed. The entrance to the depository has a deposit item thickness sensor just inside of the deposit gate opening which can detect the difference between a thicker envelope deposit item and a thinner single sheet of paper. A computer is responsive to signals from the thickness sensor to control a deflector which permits envelopes to pass directly through to a sequential stacking deposit bin. Alternately, the thickness sensor causes the computer to control the deflector to divert a single sheet of paper into a read leg of the bifurcated transport. After entering the read path, document alignment rolls placed at a slight angle to the direction of document travel tend to move the document toward a registration edge before the document passes the read head.

Abstract: A system for testing conductor lines in a printed circuit board includes circuitry for the burning out of constricted regions of the printed circuit lines so as to insure that such defects are noticed. The system includes circuitry for measuring the resistance in a path through a printed circuit line under test and including connecting circuitry to a generator of an electrical pulse. A resistor network and switching circuitry is employed for adjusting the resistance of the path through a desired value. The electrical pulse is generated by the discharge of a capacitor previously charged to a predetermined value of voltage, the discharge occurring via a pulsing circuit switch which limits the duration of the pulse through a predetermined value of sufficiently short duration to prevent damage to the circuit board associated with excessive heating.

Abstract: A pel timing clock compensates for the non-linear displacement profile of a resonant galvanometerscanner. A pel time counter is loaded with a count value and outputs a clock pulse after expiration of a delay serial determined by the count value. Each time the clock pulse is produced the pel time counter is reloaded. The various count values are accessed from a memory which is addressed by an address counter whose contents are also altered each time the clock pulse is produced. The memory stores a sequence of count values which, when used to load the pel time counter, produces the desired sequence of clock pulses to compensate for the non-linear displacement profile of the scanner.

Abstract: Repair of defects in a printed circuit board, the defects including a break in a strip conductor and a short between two strip conductors, is accomplished by use of a milling machine cutter which is operated in a direction normal to a surface of the board to bring the cutter to a repair site at the defective conductor. The cutter is then advanced partway into the conductor and translated along the conductor in preparation for soldering of braze repairing a break or, alternatively, the cutter is advanced beyond the depth of shorting material after which translation along the surface serves to rout out shorting material. Transverse movement of the cutter also removes any coating which may be present on the circuit board, which coating need be removed prior to soldering or braze repair, and may be replaced after soldering or braze repair. A microscope and pellicule are positioned for aligning the cutter with the repair site.

Abstract: In an electrophotographic printer or the like, compensation is provided for environmental effects (temperature, humidity, photoconductor aging, etc.) which would otherwise affect print quality. Analyzing print data allows identification of compensation locations; those are locations at which compensation is most critical, such as single pel lines. A series of clock pulses of varying phase displacement are employed, and selected based on environmental variations, so as to modify the print data at the identified compensation locations. The print data comprises a series of pulses. Compensation to control the width of lines perpendicular to the scan direction is effected by selectively advancing the leading edge of pulses defining a white/black transition and delaying the trailing edge of pulses defining the black/white transition. This control then affects the duration of the print pulses.

Abstract: This invention relates to a mechanism for positioning an output member of a mechanical system and in particular a mechanical system that has backlash present. The mechanism has a step motor, regulated by control means, connected to the output member by a mechanical transmission. The control means delivers units of electrical energy to the step motor in response to a number of steps specified to be moved. The control means also has means for detecting whether the step to be performed by the step motor is a single remaining step or single step only. The control means responds to detection of the single remaining step or detection of the single step only by applying a unit of energy to the step motor at a rate that is substantially slower than the rate that would be applied for the other steps.

Abstract: A method of solder leveling in printed circuit boards or other circuitized substrates. Flux is first applied to the surface of the substrate to be soldered. Molten solder is then applied to the fluxed surface after which the soldered substrate is cooled to a temperature below 300.degree. F. Molten solder is then again applied to the previously soldered surface of the substrate. This last step results in leveling the solder first applied to the substrate, including removal of any solder balls which had been formed over recessed pins and flush filling of passage holes formed in the substrate. The method can be performed without regard to the surface condition of the substrate, the composition of flux and solder, whether the substrate is of the thin film type or of the thick film type, nor whether dip soldering or wave soldering techniques are used. The invention also incompasses the end product resulting from use of the method.

Abstract: Code modification circuitry alters the end portion of each block in a sequence of code blocks, and also inserts additional bits at the junction between contiguous blocks. The codes to be processed are run-length limited (RLL) codes having a DC component which is to be removed for certain applications such as magnetic recording. The modification circuitry retains the RLL format. Charge (or the integral of the waveform) accumulated by the sequence of bits of one block is compensated by selecting the sense of charge accumulation in next block to be of opposite sense. This is accomplished by the code modification circuitry using a relatively small set of possible combinations of digital words at the junctions of the blocks.

Abstract: A coding process for a facsimile transmission system employs block coding and dither matrices of black and white picture elements, wherein each matrix represents a portion of a subject. The subject is scanned to provide gray-scale tone-level data, and the data of continuous tone regions of the subject is represented by standardized patterns in matrix form. A run of identical patterns is counted in the scanning direction and a symbol indicating the number of such repetitions is placed in the code in lieu of the succession of code words representing individual ones of the repeating patterns. A second symbol is inserted into the code to indicate a succession of runs of repeating patterns in the same column now positioned in two or more rows. The second symbol is utilized in lieu of a repetition of code words corresponding to each of the repeated patterns.

Abstract: A structure comprising on a substrate successive layers of metal circuitry having therebetween as a dielectric a cured polyimide composition containing a polyimide and aluminum oxide or zinc oxide or mixtures thereof.The structure is produced by a method including the following process steps:blanket screen printing a mixture containing a polyamido carboxylic acid, aluminum oxide or zinc oxide or mixtures thereof and a detackifier with the rest being a solvent on a substrate with a layer of metal circuitry thereon,drying the deposited layer at a temperature between about 25.degree. and about 120.degree. C.,selectively etching holes into the deposited layer where vias between adjacent layers of metal circuitry are needed,curing the deposited layer at a temperature between about 300.degree. and about 400.degree. C. andforming another layer of metal circuitry.

Abstract: A power supply/sink for use with switched inductive loads includes a transformer with a first secondary winding for generating power supply current connected in a circuit with a power supply terminal. A second secondary winding is connected in a circuit to a power sink terminal. The two secondary windings are interconnected with a controlled conduction path which is arranged to supply sink current in response to variations in the voltage at the power sink terminal.

Abstract: An extended error code particularly applicable to a code that can correct any number of errors in one sub-field but can only detect the existence of any number of errors in two sub-fields. If the initial pass of the data through the error correction code indicates an uncorrected error, the data is complemented and restored in the memory and then reread. The retrieved data is recomplemented and again passed through the error correction code. If an uncorrected error persists, then a bit-by-bit comparision is performed between the originally read data and the retrieved complemented data to isolate the hard fails in the memory. The bits in the sub-field associated with the hard fail are then sequentially changed and then the changed data word is passed through the error correction code. A wrong combination is detected by the error correction code.

Abstract: A continuous method for the manufacture of a circuit board wherein a coating of a solvent-free thermosetting resin is applied to the surface of a metal foil. The resin coated foil is advanced into contact with a reinforcing cloth sheet layer to form a foil/cloth assembly. The assembly is continuously conveyed between a pair of endless belts revolving in opposite directions with mutually facing surfaces, the belts being heated to the curing temperature of the resin whereby the belts are pressed against the assembly to continuously compact the assembly and cure the resin to form a composite product which can then be circuitized from a printed circuit board.

Abstract: A failure detector detects breakage in a machine tool cutting element, such as a drill bit, by use of a accelerometer supported against a workpiece being operated on by the cutting element. Vibrations are induced in the workpiece by the cutting operation, the vibrations having spectral components in the audio frequency range which are characteristic of proper operation of the cutting element, the spectral components changing upon a breakage of the cutting element. A voltage produced by a positioning mechanism of the cutting element identifies the location of the cutting element relative to the workpiece. A bandpass filter separates the spectral components associated with proper operation from spectral components associated with faulty operation. Logic circuitry signals the joint occurrence of the spectral components of proper operation with the position of the cutting element at the site of the workpiece so as to permit the signaling of a cutting tool failure during operation on the workpiece.

Abstract: A method and apparatus for laser cutting sheet material and especially for laser cutting composite sheet material. An inert gas shield, preferably of nitrogen, is provided at the cutting zone to minimize charred edges of the cut material and resulting in an extremely accurate and uniform cut line. The gas shield can also be used to accurately position the sheet material so as to lie at the focal point of the laser beam. Alternatively, a vacuum can draw the sheet material against a supporting surface for positioning the sheet material. In a continuous process, one or more stationary lasers operating on an advancing web of the sheet material are positioned to cut in the longitudinal direction and a movable laser is positioned to cut in the transverse direction. Mechanical expedients enable the movable laser to make a cut perpendicular to the cut made by each stationary laser without interrupting the flow of the sheet material.

Abstract: An interrupt interface circuit for interrupt level sharing comprising a pulse generator having an open-collector or tri-state output connected to an external interrupt line shared by other similar circuits. An active internal interrupt signal causes the pulse generator to pulse. The external interrupt line is fed back and latched on a disabling input of the pulse generator so that any pulse on the external interrupt line prevents further pulsing. The software handler of the interrupt, upon servicing an interrupt of the interrupt level, causes the enabling of the pulse generators of that level, thereby permitting active internal interrupt signals to produce a further pulse. By this interrupt level sharing, phantom interrupts are eliminated and servicing overhead is minimized.

Abstract: Electromigration activity is decreased and lifetime is extended in solder stripes employed as conductors and terminals on microelectronic devices by forming an alloy of a solute element, such as copper, with tin in a lead/tin solder and providing a substantially uniform distribution of particles of the intermetallic compound in the solder. The concentration of the solute element is maintained at less than about three times the tin concentration and less than about 10% of the amount of the solder.

Abstract: A multiple mode buckling beam probe is formed by top and bottom mating locating guides interposed between a space transformer die bearing exposed wire contact ends and an underlying substrate having correspondingly positioned conductive pads. Wire probes pass slidingly through aligned holes within the top and bottom mating locating guides. At least one center locating guide having correspondingly aligned holes with the top and bottom locating guides slidably receives the wire probes and is spaced at different distances from the top and bottom locating guides. Interposed between the center locating guide and the top and bottom locating guides are respective slotted guides having elongated slots through which the wire probes pass, which slots are offset relative to the top, bottom and center locating guide holes.

Abstract: A method of radiation induced dry etching of a metallized (e.g. copper) substrate is disclosed wherein the substrate is pattern-wise exposed to a beam of laser radiation in a halogen gas atmosphere which is reactive with the substrate to form a metal halide salt reaction product to accelerate the formation of the metal halide salt without its substantial removal from the substrate. The metal halide salt is removed from the substrate by contact of the substrate with a solvent for the metal halide salt.