Abstract: A voltage to frequency converter controls the successive charge-discharge of an integrating circuit charging capacitor between low and high voltage levels to produce through a reference voltage controlled pulse generating circuit, a pulse output in which the ratio of input voltage to reference voltage equals the ratio of output pulse duration coincident with capacitor discharging, to period duration.

Abstract: A solid state device such as a liquid crystal display (LCD 11) is provided with fast warm up characteristics by using an internal heater (31). The internal heater (31) preferably is located on a backplane, (13) and is used during warmup to supplement a conventional heater (41). The external heater (41) permits the LCD heater system to operate continuously at a selected temperature and not cause deterioration of the LCD (11). The internal heater (31) is electrically isolated from the device's backplane electrodes (17), for example, by the use of a thin oxide layer (33) between the internal heater (31) and the backplane electrodes (17).

Abstract: In a liquid crystal display apparatus employing a ferroelectric liquid crystal cell, two or more pulse voltages are applied to the liquid crystal cell during selected time periods within 1 frame period to drive the liquid crystal cell. These pulse voltages can maintain the display condition of the liquid crystal cell.

Abstract: A digital clip and gain circuit compares an input waveform with a clip level to produce a difference waveform. The difference waveform is shifted by an exponent representing a power of two portion of a gain value, and is then multiplied by a mantissa representing a fractional portion of the gain value. The resulting product is input to a lookup table which provides level shifting and limiting to output a control waveform. A parallel overflow logic circuit processes the difference waveform and the exponent portion of the gain value to determine if the resulting product is out of range. If the resulting product is out of range, the lookup table outputs either a maximum or a minimum value for the control waveform according to the sign of the difference waveform.

Abstract: A switchable current source is provided for providing a relatively high frequency pulsed current to a load. The current source comprises six MOS transistors responsive to an enable signal and an input comprising a pulsating digital signal provide a pulsating digital output signal substantially similar to the input signal.

Abstract: This tone decoder utilizes three correlators for detecting the presence of a desired tone signal. A main correlator correlates to the desired tone frequency, while two side correlators are used to correlate to frequencies above and below the desired tone frequency. Tone detection is indicated by correlation of the main correlation and absence of correlation by the side correlators. Improved bandwidth and/or correlation time is achieved as compared to utilizing a single correlator.

Abstract: In contrast to existing light addressed light valves for projection displays which use a homogeneous CdS or Se photoconductive layer as the control element for a liquid crystal cell, a silicon photo-diode array is disclosed which makes an effective control element capable of applying a spatially varying AC voltage across a liquid crystal light valve. Writing may be done with a miniature CRT in an optical or electron excitation mode. It is shown that for a video mode the ratio of diode capacitance to liquid crystal cell capacitance associated with the diode, and the frequency of the applied square wave voltage, define the buildup or decay time of the liquid crystal cell voltage. Thus, the frequency of the applied AC voltage can be used to control sensitivity and transient response and there is no lag. The dynamic range of the cell voltage is shown to depend on the ratio of diode capacitance to liquid crystal cell capacitance.

Abstract: A variable timing sequencer for producing sets of data which correspond to different current states of the sequencer, wherein the interval of each such set of data corresponds to said current state and user input, and said current state is determined by a previous state and input data. This separation of the time domain sequencing from the functional sequencing allows operation of functional components at lower frequencies than the timing components and the increase of effective memory density. The ability to affect both current state and interval by means of an input permits the sequencer to be used in a variety of conditions and applications with a minimum amount of reprogramming.

Abstract: A sense amplifier circuit for single-ended data characterized by the responsiveness of the reference voltage to variations in processing parameters and tolerance for noise. Matching of the dataline voltage to the reference voltage enables the comparison of data with the reference to operate with greater accuracy. Isolation of the reference voltage preserves its integrity as a high logic state from subsequent variations in the dataline.

Abstract: A clock generator for CMOS circuits for producing two non-overlapping internal clocks or timing cycles at two clock outputs, the clock generator having a frequency divider energized by an oscillator and having an output side, and a bistable multivibrator connected to the output side of the frequency divider and having complementary outputs includes an equal number of inverter-driver stages connected to each of the complementary outputs and being controllable thereby, the driver stages being dimensioned asymmetrically.

Abstract: A temperature compensation system for semiconductor digital or analog circuits where the temperature compensation is accomplished by two depletion mode MESFETs. A first MESFET is adapted to operate as a level shifter in the linear region of operation only in combination with a second MESFET adapted to operate in the saturation region of operation.

Abstract: A process for the sequential control of a liquid crystal display means having different optical responses in alternating and steady fields. This process consists of applying to one side of a first electrode an a.c. potential V.sub.1 and to the other side an a.c. potential V.sub.2, with V.sub.2 -V.sub.1 constant, so that only line Y parallel to the sides of the first electrode is exposed to a reference potential V.sub.0 ; applying to one side of a second electrode an a.c. potential V.sub.3 and to the other side an a.c. potential V.sub.4, with V.sub.4 -V.sub.3 constant, so that only the line X parallel to the sides of the second electrode, intersecting the first, is exposed to V.sub.0 ; and applying a d.c. potential V.sub.5 to the two sides of one electrode, so that liquid crystal zone XY defined by the intersection of lines X and Y is only subject to potential V.sub.5 and that outside the zone the liquid crystal is subject to an a.c.

Abstract: The invention is relative to a method of statically (non-multiplexed) actuating a liquid crystal display which comprises several segments and a common back electrode, using a microprocessor which serially outputs the data to be displayed, and using a serial/parallel converter which statically makes the data to be displayed available for each segment of the liquid crystal display. The invention has the task of achieving recognition of functional error as follows: The data to be displayed is outputted approximately every 0.1 second by the microprocessor and the data for the individual segments and for the back electrode is inverted at every second data output. The failure of components then results in a blinking of the particular segment and is conspicuously indicated in this manner. In the case of alternating voltage actuation of the liquid crystal display, it is advantageous if the clock pulse of the alternating voltage actuation is also inverted at every second data output.

Abstract: A liquid crystal spectacle includes a pair of liquid crystal lenses and a frame holding the lenses. The frame has a pair of temples and a pair of ear pieces attached individually to the temples. Each ear piece houses a battery for supplying the voltage to the corresponding lens. Each temple houses a regulator circuit for regulating the voltage supplied from the battery to the lens, thereby controlling the refractive index of the lens.

Abstract: There is disclosed a liquid crystal display device having very uniform contrast ratio for use with such a projector as an overhead projector. The liquid crystal display device comprises a liquid crystal display cell having a thin film of liquid crystal material sandwiched between transparent electrodes formed on opposing transparent substrates and a Fresnel collimating lens disposed before the cell in the direction of light traveling through the cell and for collimating the light in parallel light beams from a condenser lens in the projector.

Abstract: A sample clock signal generator is implemented to output a signal that is phase-synchronized with an external signal having a frequency that is significantly lower than that of the output signal. The output signal is obtained by generating a series of time-separated signals each having the desired frequency and selecting as the output signal that one of the series having a falling edge occurring after a predetermined transition of the external signal.

Abstract: Apparatus for providing automatic clock de-skewing for a plurality of circuit boards of a data processing system. In a preferred embodiment, each circuit board is of multi-layer construction and contains a clock distribution chip which includes on-chip automatic clock de-skewing circuitry for providing de-skewed clocks to other chips on the circuit board. In a preferred implementation of the clock de-skewing circuitry, feedback circuitry including a multi-tapped delay line and an accurate reference delay are employed in conjunction with a phase comparator for automatically providing de-skewed clocks at the clock outputs of the clock distribution chip. The accurate reference delay is advantageously provided by a strip transmission line formed in a conductive layer of the multi-layer board containing the chips.

Abstract: A display assembly for an LCD device is disclosed wherein the LCD essentially comprises an elongated horizontal plate. The LCD is mounted in a recessed portion of the top surface of a carrier made of light transmitting material with preferably the back surface of the LCD contacting the carrier top surface. Beneath the LCD, the carrier has an effective wedge-shaped portion, or at least an inclined planar surface of the carrier, and a light source is effectively positioned adjacent the carrier. At least one retainer member is utilized to mount the LCD to the carrier with edges of the carrier top surface recessed portion laterally surrounding and thereby laterally locating the LCD device with respect to the carrier. The preceding configuration allows the carrier to provide for backlighting of the LCD since the carrier serves as a light pipe in addition to providing mounting structure for the LCD.

Abstract: Integrated control, active matrix display means comprising two groups of row electrodes and two groups of column electrodes per image point and the control process for the same. This means comprises a display material inserted between two walls on the inner faces of which are arranged n parallel row conductors and two groups, each formed from m parallel columns, one of the two groups being raised to reference potential and each row conductor being connected to m switches, themselves connected to two conductor blocks of first and second groups facing column conductors of first and second groups. An image point is defined by the overlap zone of two column conductors and two conductor blocks respectively of a first and second groups.

Abstract: A method of providing automatic clock de-skewing for integrated circuit chips carried by a multi-layer circuit board. In a preferred implementation of the method, a clock distribution chip includes on-chip automatic clock de-skewing circuitry requiring an accurate reference delay which is advantageously provided by a strip transmission line formed on one of the conductive planes of the multi-layer circuit board containing the chips.