Abstract: A laser diode driver chip is disclosed which has a circuit to substantially reduce a ringing on a laser diode driving current generated by the laser diode driver chip. This invention identifies that the ringing on the laser diode driving current is caused by three different resonances which are coupled together. This invention also suggests a model for the sources of these three different resonances and identifies the three main nodes which are common between the sources of resonances. Finally, this invention places a damping circuit between the three main nodes of the laser diode driver to substantially reduce the ringing on the laser diode driving current.

Abstract: A high voltage switch in which an extended SCR is built in an insulated polysilicon layer for providing a single structure high voltage switch. The high voltage SCR is built by building unit SCRs comprising a cathode, a gate, an anode and a voltage sustaining area. The unit SCRs are built as horizontal linear devices. The unit SCRs can then be combined to form a large SCR by building each unit SCR so that the anode of one SCR is at least partially contiguous with the cathode of the next unit SCR.

Abstract: There is disclosed a layout of a high voltage Darlington pair in which a circular field plate is utilized for both high voltage transistors in order to reduce the layout area. In this layout, both transistors of a Darlington pair are circular transistors and they both have a common center. This enables both high voltage transistors to share one field plate ring and one collector ring.

Abstract: An electrostatic voltmeter suitable for use in a non-contacting, positive or negative potential sensing, type electrostatic voltmeter. The invention enables a flexible, low cost electrostatic voltmeter to be produced using high-voltage field-effect transistors in the circuit design. The invention further includes input conditioning components that enable high-voltage sensing and high-voltage feedback in such a manner that processing of the input signal from the sensor is accomplished without producing a variation in the current passing through the field-effect transistor in response to voltage variations. Elimination of this variation further reduces the susceptibility of the remaining signal processing circuitry to transient direct current signals. A differential cascode as the input stage is the preferred configuration for the input conditioning components.

Abstract: An electronic compensation circuit in which a simulation of a laser's thermal droop characteristics is used to adjust input to the laser and thereby compensate for the laser's thermal droop effects. The simulation circuit is connected to the laser either as an open loop circuit to provide a once only correction or as a closed loop feedback circuit to provide a continuous correction of the laser droop effects. The simulation circuit is designed using either analog or digital circuitry and is adjustable to provide compensation for lasers having different time constants of droop or different values of droop.

Abstract: A vertical transistor which is built in a substrate of a given first carrier type utilizing standard processes but which has a unique layout which facilitates high voltage, high current operation while still conserving space. The transistor is built utilizing a repeatable combination gate/source area that is built in the upper area of the substrate such that the remaining lower portion of the substrate underneath the combination gate/source area is the drain area of the transistor.

Abstract: A semiconductor circuit integrated with CMOS circuits for receiving a TTL input voltage and generating a large negative and positive voltage swing with respect to p-type or n-type substrate is disclosed. This invention is based on elimination of the electro-static discharge (ESD) protection circuit which is a requirement for any integrated circuit. Eliminating the ESD protection circuit also eliminates the clamping feature of the ESD protection circuit and therefore the circuit can be driven to negative voltages for PMOS circuits and to positive voltages for NMOS circuits. This provides the possibility of connecting the drain of a a P-channel type metal oxide silicon field effect (PMOS) transistor, which is fabricated on a p-type substrate within an n-well, to a voltage below the the substrate voltage. Also, in a n-channel type metal oxide silicon field effect (NMOS) transistor which is fabricated on a n-type substrate within a P-well, the drain can be connected to voltages higher than the substrate voltage.

Abstract: An apparatus and method for detecting and reducing image transfer smear is provided. A pattern consisting of a sequence of toner characters or marks separated by spaces is written and developed on a photoreceptive member and then transferred to an intermediate medium. As the pattern is transferred to the intermediate medium, the velocity of the photoreceptor is varied. A photodetector is used to detect the transferred pattern on the intermediate medium and generate a signal indicative thereof. As the detector senses the absence of toner, the signal generated is greater when the space between the toner characters is largest. By monitoring when the signal is greatest and determining the corresponding velocity of the photoreceptor at that time, the best velocity match between the photoreceptor and intermediate transfer medium can be determined and set.

Abstract: A layout of a MOSFET current driver is disclosed which improves the fabrication yield and the current drive capability over that of the prior art while keeping the layout area the same as the prior art. In this design, the gate is laid out to have a lateral serpentine pattern rather than a vertical serpentine pattern to create a larger gate in order to improve the current drive capability. In addition, the contacts for the drain and the contacts for the source are removed from the gate layout area which facilitates condensing the gate layout and increasing the size of the gate. Also, this design has only two metal strips: one for the drain and one for the source of the MOSFET current driver. The two metal strips substantially overlap the serpentine patterned gate. Having only two metal strips reduces the spaces between the metal strips to one space thereby reducing the probability of having a short or a defect and improving the fabrication yield.

Abstract: The present invention provides an ink jet printhead that is provided a bias voltage and that includes at least one ink channel, a heating element, and an interconnect. The ink channel has an open end that serves as a nozzle, and the heating element is positioned in the channel for ejecting ink droplets from the nozzle by selective application of current pulses along the interconnect to the heating element. The printhead further includes a conductive protective region that is positioned adjacent the heating element and that has a portion thereof exposed to the ink channel for protecting the heating element from ink. Positioned between the conductive protective region and the heating element is a dielectric region for insulating the heating element from the conductive protective region. The printhead also includes a bus for connecting the bias voltage to the conductive protective region.

Abstract: A method of manufacturing a semiconductor device having a bipolar transistor for ordinary logic operation, as well as a high voltage MOS transistor which are provided in a single semiconductor substrate. The process includes the steps of making high voltage MOS transistors which comprises the steps of n-well fabrication, first drift region fabrication, second drift region fabrication, source and drain contact region fabrication and making bipolar transistors within the same silicon substrate as the high voltage MOS transistors which includes the step of base region fabrication where the steps for fabricating the second drift region of the high voltage MOS transistor and the base region of the bipolar transistor are combined so that both regions are created simultaneously.

Abstract: A plurality of binary diffractive optic lenses are formed in the surface of one substrate and a corresponding plurality of recesses are formed in the surface of another substrate. The binary diffractive optic lenses on one substrate are aligned with the recesses on the other substrate and the two substrates are bonded together. A plurality of individual binary diffractive optic lens cover assemblies are obtained by dicing the two bonded substrates.

Abstract: A thermal ink jet printhead with a plurality of newly designed bubble containment chambers for reducing a spattering effect which is the ejection of unwanted small aerosol type droplets after the ejection of an ink drop. The printhead has one or more ink channels each having an opening at one end, known as nozzle, and also having a bubble containment chamber for each channel at a predetermined distance from the nozzle. The new bubble containment chamber is designed to absorb or redirect undesired acoustic waves produced from the collapse of a bubble in the bubble containment chamber which in turn causes the ejection of unwanted small aerosol type droplets after the ejection of an ink drop. The bubble containment chamber of this design absorbs or redirects the acoustic energy by having four different kinds of wedges on its walls.

Abstract: A plurality of binary diffractive optic lenses are formed within a corresponding plurality of recesses in the surface of one substrate. The substrate with the binary diffractive optic lenses in the recess are bonded to another flat substrate. A plurality of individual binary diffractive optic lens cover assemblies are obtained by dicing the two bonded substrates.

Abstract: A position detector for a scanning beam comprising a plurality of rows of spaced apart sensors. Each row of sensors includes a plurality of logic zero sensors and a plurality of logic one sensors which are arranged in alternating logic order. Each row is arranged such that it is symmetrical about its center. Equal areas of logic zero sensors on each side of the center are equal distances away from the center and equal areas of logic one sensors on each side of the center are equal distances away from the center to substantially cancel out any background light effects on the sensors.

Abstract: A new and improved semiconductor thermoelectric device which could be used either as a thermoelectric cooler or as a thermopile heat sensor with high output voltage. This invention comprises an array of thermocouples fabricated on a semiconductor substrate. The thermocouples comprise segments of tantalum and segments of conductively doped polysilicon as two electric conductor materials of different thermoelectric properties which are buried between two layers of oxide. A layer of metal as a heat collector covers the surface of the thermopile and distributes heat from a nearby heat source.

Abstract: A new and improved flip chip combination of a laser diode chip and a carrier chip with built-in thermoelectric cooler. This invention comprises an array of laser stripes, each having a separate cooling strip bonded to it. Each cooling strip could be controlled either separately or by a common source, permitting cooling of each laser stripe at a different rate or at the same rate respectively, to thereby maintain the laser stripes at the same or different operating temperatures.

Abstract: A thermal ink jet printer utilizes a printhead whose electrical connections to the heating elements used to expel the ink droplets has been modified to reduce the effects of parasitic resistance of a first power bus when a number of resistors are simultaneously addressed. The first power bus has been modified by forming and interconnecting to it a second power bus using a low resistance connection which is formed to crossover, or under, a common return. The second power bus is connected at each end to a predetermined voltage, while the first power bus is connected at each end through a series ballast resistor to the same predetermined voltage.

Abstract: This bubblejet device has integrated into it a number of heater resistors and a temperature sensor which operate in conjunction with a temperature regulating circuit to heat the chip to its optimum operating temperature within seconds of turn-on, and thereafter maintain that temperature regardless of local temperature variations. The precise temperature regulation of the array improves print quality.

Abstract: The ink in an ink jet is sensed by a capacitor, one plate of which is coupled to ground through the ink. The absence of ink will appear as a decreased amount of capacitance. In this case the charge of the capacitor will leak off faster, and a sample and hold circuit can sense this to output a signal indicating the absence of ink. The charging signal can either be generated on the chip, which is made from silicon, or can be supplied to the chip. The number of pins on the chip taken for this sensing function can be minimized by multplexing the states of signals supplied to the chip for other purposes to generate the necessary signals to control and operate this sensor.