Abstract: A method and apparatus for measuring very low light signals including integrating a signal from a photo diode, avalanche photo diode, photomultiplier tube or the like, digitally sampling the integrator output more than two times during each integration period, fitting a curve to the multiple digitized readings to calculate the integration slope for each integration period and determining the original signal from the calculated integration slope.

Abstract: A light sensing apparatus for different control systems includes a photosensitive element which generates a light current depending on light incident thereto. A pre-circuit connected to the photosensitive element is operative for generating separate basic signals in response to the light current generated by the photosensitive element. Processing circuits connected to the pre-circuit are active simultaneously for converting the basic signals generated by the pre-circuit into conversion-resultant signals having different forms respectively. The conversion-resultant signals are outputted to the control systems respectively. At least one of the processing circuits may include an oscillation circuit which oscillates at a frequency depending on related one of the basic signals generated by the pre-circuit.

Abstract: A self adjusting tuned resonant photodiode input circuit wherein an active feedback signal adjusts a reverse bias voltage across a photodiode to tune a resonant frequency to a center frequency. This results in a stable improved passband of the receiver front end.

Abstract: A night vision device includes an improved power supply which operates the image intensifier tube of the device according to a variable duty cycle either at a design voltage level for the tube or at a voltage level simulating a dark-field. This duty cycle variation is effected as a function of the current flow in the image intensifier tube in order to provide automatic brightness control and bright source protection.

Abstract: A converter for providing an electrical signal according to the status of a light spot applied thereto, comprises: a sensor for sensing the light spot and generating a position current according to the position of the light spot sensed thereat; and an operating circuit for providing the sensor with an operating current when the light spot is sensed by the sensor and for outputting a status current corresponding to the operating current. The sensor comprises two electrodes each providing a current with magnitude determined according to the distance between it and the position of the light spot sensed thereat. The position current is obtained by subtracting the first electrode current from the second electrode current.

Abstract: A capacitor coupled bipolar phototransistor having an integrated electronic shutter for reducing the overflow and blooming problems associated with the imaging of strong images. Overflow control and an anti-blooming mechanism are obtained by use of a second emitter (the "shutter") which is used to remove excess image generated charge. This prevents the base-emitter junction potential from becoming forward biased during image integration when the phototransistor is exposed to a strong image. The shutter is biased slightly lower than the first emitter of the phototransistor so that the base-shutter junction is forward biased sooner than the base-emitter junction when the imaging element is exposed to a strong image. The overflow current of the generated holes is then drained to the shutter, rather than into the emitter where it would produce noise on the column sense line.

Abstract: The invention is a circuit for eliminating or reducing unwanted components from an optical output signal. The circuit employs a photodetector for converting a portion of the output signal to an electrical signal, and a feedback loop which passes only the second harmonic band or the frequency difference band for combining with the input biasing signal.

Abstract: A pair of interleaved finger-like electrodes are positioned over a pyro-electric sheet of polyvinylidine fluoride and a pair of coatings are formed upon the electrodes having different optical reflectance, and as a result, a light beam energy absorption differential will be produced between the coatings and the resulting change in temperature in the sheet material under the electrodes will cause a voltage to be generated. A differential amplifier is connected across the electrodes to sense this voltage, indicative of the detection of an incoming laser light beam. A light chopper is positioned to interrupt the light beam directed at a portion of the pyro-electric sheet.

Abstract: A system and method for optimizing the signal range of a photocell for all ambient lighting conditions. A switched resistor circuit is serially connected to the photocell. The duty cycle of the switched resistor circuit is controlled to provide an optimal signal range for the photocell in both light and dark ambient light conditions.

Abstract: A multi-channel electromagnetically transparent voltage probe transmission link system for monitoring a plurality of voltage signals at a plurality of test points of a device under test that is subjected to a radiation field. Each channel includes two voltage probes, an electrical to optical signal transmitter, an optical signal transmission line and a receiver located out of the radiation field. The voltage probes contact and sense the voltage signals at the test point. The electrical to optical transmitters are removably mounted in a common base and are powered by either a common (or shared) power supply and/or by dedicated power supplies, such as rechargeable batteries. The receivers process the optical signals and provide display signals corresponding to the sensed voltage signal at the plurality test points for evaluating the effect of the test radiation field.

Abstract: Luminous energy of a light-emitting element in an optical device is adjusted to a desired level by a light adjusting circuit including a light-receiving element adapted to detect the level of luminous energy of light emitted from the light-emitting element, an up/down counter circuit for counting clock signals up or down according to the level detected by the light-receiving element, and a current adjusting circuit for resetting the current intensity supplied to the light-emitting element according to output data from the up/down counter circuit.

Abstract: A light chopper periodically transmits and blocks light, and first a dark current cancelling circuit determines an approximate mean value of the dark current from a photodiode when the light is blocked and cancels thus the mean value from the current signal fed into the integrated circuit, add to this, a differential arithmetic circuit that subtracts the remaining dark current component from the output of the integration circuit, thus the remaining signal indicates only the signal current component.

Abstract: A photoconductor-based electrical switch comprises an element made of photoconductor material possessing two electrodes located. on either side of an active zone, at least one light source emitting at least one light beam illuminating the active zone, the beam having a wavelength corresponding to a level of photon energy lower than the bandgap energy of the photoconductor material, the intensity of the light beam being such that there is a combination of the energy of at least two photons in the photoconductor material, in such a way that a mechanism of two-photon absorption in the photoconductor material contributes to the creation of carriers enabling the photoconductor material to be made conductive.

Abstract: A multi-function day/night observation, ranging, and sighting device includes a single objective lens and a single eyepiece lens and provides an image of a scene. The single objective lens leads to a visible-light first optical path and to an invisible-light second optical path. The invisible-light second optical path includes an image intensifier tube providing a visible image. The first-and second optical paths converge with visible images provided by each pathway being overlaid at a reticule plane. A single light path leads from the reticule plane to the eyepiece lens. A laser provides a pulse of laser light projected into the scene via the single objective lens, and the image intensifier tube is used as a detector for a portion of the laser light pulse reflected from an object in the scene in order to provide a laser range finding function.

Abstract: An active pixel sensor implemented with CMOS technology that employs a plurality of photocells, each including a photodiode to sense illumination and a separate storage node with a stored charge that is discharged during an integration period by the photocurrent generated by the photodiode. Each photocell includes a switching network that couples the photocurrent to the storage node only during the integration period while ensuring that a relatively constant voltage is maintained across the photodiode during integration and non-integration periods. The transistors in the switching network operate in a forward active subthreshold region, ensuring linear operation and the diode voltage is clamped to a small positive voltage so that the diode is always reverse-biased. A source-follower generates a output signal correlated to the charge on the storage node that is coupled to column output circuitry that samples the signal.

Abstract: The invention provides an imaging system for the detection and sorting of objects in a work space. The invention uses a modulated electromagnetic signal and then filters each received signal. The received modulated signals by an array of photosites are used to create an image of an object.

Abstract: A feedback element for a two beam smart pixel receiver having at least one pair of electron devices of opposite electrical conductivity type, such as an NFET and a PFET, with input electrodes electrically connected and output electrodes electrically connected. The devices of a pair have opposing differential resistance characteristics in response to the same input signal so that the resistances of the devices of the pair add to become more linear.

Abstract: An optical communication device is provided. One or more pairs of matched diode lasers are located at first and second stations and are connected by a fiberoptic cable. A bit stream is applied to the output beam of the laser or lasers at the first station. The output beam carrying the bit stream passes through the fiberoptic cable to the matched laser or lasers at the second station and combine with the output beam of the receiving laser cavity at the second station to form a combined output beam. The power of the combined output beam is measured and time-dependent changes in the measured output power of the combined output beam is used to read the bit stream. Multiple pairs of matched lasers using different wavelengths may be positioned at the first and second stations. In yet another form of the invention, a frequency injection technique is utilized to modulate the output beam and a deconvolution system is provided to read the bit stream or streams.

Abstract: A device and method capable of converting a position signal into a frequency signal using a photoelectric position sensitive detector is provided. The device capable of converting a position signal into a frequency signal comprises: a PSD, two current mirrors, a variable optimum constant current source, and a converter. The method capable of converting a position signal into a frequency signal comprises: providing a PSD, providing two current mirrors, providing a variable optimum constant current source, and providing a converter to convert a position signal into a frequency via a relationship.

Abstract: An optical pickup is provided which detects information contained in an optical disk. The optical disk includes a light source, a hologram device, an objective lens, a photodetector, and a single chip. The light source is formed of a first vertical cavity surface-emitting laser (VCSEL) diode and emits a light beam. The hologram device converts the light beam emitted from said light source into a polarized parallel light beam and diffracts a reflected parallel light beam reflected from said optical disk to produce a diffracted beam. The objective lens focuses the polarized parallel light beam on said optical disk and converts a corresponding reflected beam into the parallel reflected beam. The photodetector is formed of a second VCSEL diode and detects various characteristics of the diffracted beam. Finally, the light source and the photodetector are integrated on the chip.

Abstract: A photosensor circuit comprises a photoelectric transducer, an n-channel MOS transistor and an initial setting unit for precluding the occurrence of a residual image phenomenon. When an optical signal is generated by the photoelectric transducer, the initial setting unit sets the gate voltage of the n-channel MOS transistor at a high value for a predetermined time to lower the drain-source impedance of the n-channel MOS transistor to thereby control charge or discharge of a capacitor connected to a source terminal.

Abstract: The invention relates to a method as well as to apparatus for testing the function of microstructure elements, wherein the microstructure element is driven for testing the emission and/or mechanical properties and the corpuscles emitted or reflected by it are detected and evaluated.

Abstract: A wide-band tuned photodiode input circuit comprising: a photodiode; an step up double tuned network having an input and an output. The double tuned network is responsive to the photodiode. The input is capacitively coupled to the photodiode.

Abstract: There is provided a measuring board, in which an I/O switch is formed in the vicinity of an I/O terminal on the board and no deformation occurs in the wave form of an input signal. In the vicinity of the I/O terminal on the measuring board, on which a device to be measured (DUT) is mounted and in which testing is performed for the I/O terminal, there are provided a plurality of optically driven switches, each of which is composed of a photoconductive switch having electrodes with an electrode gap of a specified width on a semi-insulating semiconductor substrate and a semiconductor laser provided so as to irradiate the electrode gap. By these optically driven switches, input and output switching is performed for the I/O terminal.

Abstract: The present invention includes two photodiodes in parallel connected to some transistors and an adjustable current source. The photocurrent difference from the two photodiodes combines with the current form the current source to be a positive value. This current then charges a capacitor. An automatic comparator circuit detects voltage of the charging capacitor. The Q output of the RS flip-flop is low and the transistor is off to charge the capacitor if the voltage of the capacitor is below a preset value. The buffer output is at low voltage in this case; The Q output of the RS flip-flop is high and the transistor is on to force discharging of the capacitor and the buffer output is at high level when the capacitor voltage reaches a preset value. By repeating these conditions, frequency modulated output can be obtained. The frequency value is related to the two light intensities difference and the current source combined current. When light intensity varies, the frequency varies accordingly.

Abstract: An integrated photonics device is described. The integrated photonics device includes a photo detector having an active area. A substrate has a side surface intersecting a top surface of the substrate at a predetermined angle. The side surface is reflective. The photo detector is bonded onto the top surface of the substrate with the active area of the photo detector facing the side surface such that light traveling parallel to the top surface of the substrate can be reflected onto the active area of the photo detector via the side surface. A method of fabricating the integrated photonics device is also described.

Abstract: A device and a method for eliminating interference signals in a light barrier. The device includes, having a transmitter, a receiver and an evaluation unit that is connected to the receiver. The transmitter periodically emits light pulse trains with a defined pulse length T.sub.P and a defined period length T.sub.s. In the evaluation unit, the received signals present at the receiver are evaluated only during activation intervals that are limited in time. The length of the activation intervals depends on whether light pulses are recorded during these activation intervals.

Abstract: A pre-biasing technique for a transistor-based avalanche circuit which improves the initial rate of rise in the current applied through a laser diode or other light emitting device in a laser based distance measurement and ranging instrument and, therefore, the sharpness of the leading edge of the laser pulse produced. Since the timing of the flight time of a laser pulse to a target and back to the ranging instrument is determined with reference to the leading edge of the emitted laser pulse, the inherent precision obtainable is enhanced by the production of a sharper leading edge pulse. Through the use of the pre-biasing technique disclosed, the very rapid rise time pulse which may be achieved also allows for the substitution of a much cheaper light emitting diode in lieu of a conventional laser diode in an alternative implementation of a light pulsed-based distance measuring and ranging instrument.

Abstract: A timed photocell switching circuit is disclosed which senses a light-to-dark transition and applies power to a lamp load for a preset period of time. After the preset period has expired the timed photocell circuit turns the lamp load off for the remainder of the night until a dark-to-light transition resets the circuit after which it can be triggered for another timing cycle. Once the light-to-dark transition triggers the timing cycle the ambient light level cannot disrupt the circuit. In addition, the circuit can be reset regardless of its timing position by momentarily cycling power to the circuit.

Abstract: A circuit is provided for adjusting an operating point of an opto-electronic element having a saturation voltage and which constitutes a component of a receiver for alternating light useful signals and which generates current during a short-circuit operation and voltage during a no-load operation. The circuit comprises a resistive circuit connected in parallel with the opto-electronic element for adjusting the operating point of the opto-electronic element below the saturation voltage for the compensation of constant light signals. The resistive circuit includes an automatic control resistor which changes its resistance as a function of voltage when a specific voltage below the saturation voltage is exceeded for loading the opto-electronic element until the specific voltage is essentially reached.

Abstract: A boosting circuit comprises a power supply terminal, an output terminal a one-way element and a one-way element for charging. The one-way element comprises a plurality of stages connected in series across the power supply terminal and the output terminal in a forward direction going from the power supply terminal to the output terminal, with clock pulses being applied between each of the one-way element stages. The one-way element for charging is connected in parallel with the one-way element in the forward direction. It is therefore possible to provide a boosting circuit with an improved boosting voltage rise characteristic without having to change the size of the circuit elements.

Abstract: An improved photodetector integrator circuit is provided having a photodetector, such as a photodiode, which produces photocurrent responsive to incident illumination. The photodetector is coupled to an integrator stage which converts the photocurrent into voltage and integrates the voltage over an integration period to provide an output signal. A window comparator in the circuit receives the output signal from the integrator stage and compares the output signal to a first threshold and a second threshold to provide, as a measurement signal, a pulse having a width which corresponds to the time interval over which the output signal increases from the first threshold to the second threshold. In the window comparator, the second threshold is greater than the first threshold.

Abstract: A pulse generator is provided with a photoconductor in which first to third transmission lines composed of conductive film are formed on a semi-insulating substrate and the transmission lines are separated by first and second narrow gaps, and provides short pulses from short electrical pulses generated on these transmission lines in accordance with short optical pulses irradiated upon each narrow gap. Semiconductor lasers effect the irradiation of short optical pulses upon the first and second narrow gaps. A delay is conferred upon short optical pulses irradiated upon one of the first and second narrow gaps such that pulse height of short electrical pulses generated on the first to third transmission lines is maximized.

Abstract: An electro-optic detector senses induced photovoltages in a semiconductor structure through use of an electro-optic sensing material. The sensing material is closely positioned to the surface of a semiconductor structure so as to be locally affected by electric field changes which occur as a result of induced photovoltages. An interrogating optical beam is directed at the semiconductor structure so as to induce locally positioned photovoltages at a surface thereof. An optical sensing beam is directed at the electro-optic sensing material and a detector senses reflections of the optical sensing beam from the electro-optic layer both in regions affected by the local photovoltage field changes and in regions not affected by the local photovoltage field changes. Characteristics of the semiconductor structure are deduced from reflection data derived from the optical sensing beam.

Abstract: A light sensing device including at least one light sensor is provided. The at least one light sensor is configured to be exposed to a light image. In response to the light image, the at least one light sensor is configured to generate a first signal. The light sensing device further includes a measuring device coupled to the at least one light sensor. The light sensing device also includes a sampling generator configured to generate a sampling signal to the measuring device. The sampling signal is inhibited when the first signal is lesser than or equal to a predetermined value. Upon inhibition of the sampling signal, the measuring device retains a measure of the first signal.

Abstract: A method for preventing laser jamming of night vision goggles having a gated image intensifier device and a display for displaying an intensified image of a scene. The method includes the steps of detecting laser pulses from a jamming laser source and producing respective electrical pulses in response thereto, and gating off the gated image intensifier device in synchronism with the electrical pulses in order to thereby prevent the laser pulses from affecting the intensified image of the scene displayed by the display.

Abstract: Devices for measuring one or more properties of a light signal is disclosed. More particularly the invention relates to devices for wavelength and power demodulation based on the use of quantum well electroabsorption photodiodes. In one aspect the invention provides and power and wavelength demodulation system based on a quantum well electroabsorption (QWEA) filtering detector. The input optical signal passes through an optical beam splitter with part of the signal input into a filtering detector which is a multiple quantum well electroabsorption (MQW EA) photodiode having a tunable bandgap and the other part into a reference detector. The input light signal is impinged on the QW diode perpendicular to the plane of the quantum wells. The output of filtering detector is amplified by an amplifier and the output of the reference detector is input into another amplifier. The output from reference detector amplifier serves as a measurement of the power of the input optical signal.

Abstract: A light sensing array device including an array of photoelectric light sensing elements (10) individually addressable via sets of address conductors (12, 14) for use, for example, in image sensing or data input using a light pen, which is operable also in a power generating mode in which sensing elements in the array produce electrical power in the manner of a solar cell. To this end, the sets of address conductors are selectively connected via switching means (20, 21, 37, 38) to power output terminals (42, 43). The generated power may be used to supplement a power supply, e.g. using a battery pack, of the device or of electronic apparatus, such as a notebook computer, incorporating the device.

Abstract: An imager using an array of photodiodes that does not require non-standard voltages nor multiphase clocking schemes and retains good linearity with low fixed pattern and random noise generation while requiring a minimum of silicon area is described.

Abstract: An input device for a Programmable Logic Controller is taught. Briefly stated, an incoming input voltage is rectified with an input impedance being principally capacitive in order to avoid heat dissipation. This rectified power in turn cooperates with a current source such that once a set point is reached the current source current does not increase with increasing input voltage. The current source is also utilized prevent off-state leakage current from turning on an input optocoupler by allowing most of the input current to be drawn through the current source until a turn-on threshold which is set by a zener diode is met.

Abstract: During the collection operation for the imaging data of the optical image supplied to the light receiving unit in which the vertical light receiving sections are horizontally arranged, each vertical light receiving section having the light receiving devices arranged vertically therein, among the integration circuit, the buffer circuit, and horizontal reading-out section, which are arranged in each horizontal signal processing section, the integration circuit and the buffer circuit are rendered at non-operation state during the horizontal reading-out operation controlled by the timing control section, so that power is not consumed substantially during the horizontal reading-out operation. As a result, the image picking-up of the optical image supplied to the light receiving unit can be executed with a high S/N ratio and low power consumption, thereby providing a solid-state imaging apparatus which is capable of picking-up the image with a high S/N ratio and achieving a reduction in power consumption.

Abstract: A method for generating quasi-sinusoidal signals includes illuminating an object capable of diffusely scattering Eight, focusing a portion of the scattered light on a multi-element sensor to form an image, and matching the image size to the size of the sensor elements.

Abstract: Pairs of signal input leads with a low level signal imposed across them usually have noise induced by stray coupling capacitance which is typically unequal. This results in an unfavorable signal to noise ratio. Adding enough capacitance to the lead having the least capacitance, thereby equalizing the coupling capacitances to the noise services thereof, tends to reduces the noise effect considerably. This is accomplished by changing the relative sizes of the anode and/or cathode of a corresponding sensor device. The noise effect is further reduced by a negative feedback process which comprises extracting the induced noise component from the leads, inverting the noise component, and coupling the inverted noise component back to the input leads.

Abstract: An photodetector circuit comprising an avalanche photodiode having a signal input for receiving an input optical signal to be converted to an electrical signal. The photodetector circuit further includes biasing circuitry, coupled to the avalanche photodiode, for applying a bias voltage to the avalanche diode. The bias circuitry includes: (1) a dc bias circuit for providing a dc component to the bias voltage for maintaining the avalanche diode in a stable avalanche gain condition when receiving the input optical signal; and (2) a modulating circuit for providing a high frequency modulating component to the bias voltage for modulating the bias voltage in a manner that enhances the operational characteristics of the avalanche photodiode. In particular, the modulating component to the bias voltage decrease the noise of the signal output of the avalanche photodiode for a given average gain, and increases the bandwidth of the signal output of the avalanche photodiode for a given average gain.

Abstract: A double four-quadrant angle position detector is disclosed. The angle position detector comprises a first orientation detector, a second orientation detector, and a detecting means. The first orientation detector is composed of two pairs of photo-detecting means, arranged on opposite sides along vertical and horizontal directions, respectively, to generate output currents according to the brightness level. Similarly, the second orientation detector can also generate output currents according to brightness level. The detecting means determines a first angle and a second angle according to these output currents and then compares the difference of the first angle and the second angle with a preset threshold. When the difference is greater than the preset threshold, it indicates that an image angle is passing through the sensor.

Abstract: A solid state imaging device includes a light receiving portion having a first photodiode and a second photodiode whose potential well is deeper and whose photosensitivity is lower than that of the first photodiode, and a transmitting portion having a first transmitting gate for transmitting charges accumulated in the first photodiode to a transmission device and a second transmitting gate for transmitting charges accumulated in the second photodiode to the transmission device. Thus, the dynamic range of the solid state imaging device becomes wider.

Abstract: A light receiving circuit provided with an amplifier for amplifying an output signal of a semiconductor light receiving element is disclosed. The amplified electrical signal is first inputted to the inverting input terminal of a comparator. An output voltage of the comparator is divided by resistors connected in series with each other. The difference voltage between the voltage applied to the inverting input terminal and a voltage being present at a connection point between the resistors is divided by means of resistors, and a voltage obtained by this voltage division is then applied to the non-inverting input terminal of the comparator. The amplitude of an output voltage of the comparator is reduced by dividing this output voltage. Moreover, the mean value of this output voltage thereof can be made to be closer to the ground potential. Therefore, when the output of the comparator has a high level, a threshold voltage to be applied to the non-inverting input terminal becomes lower.

Abstract: An improved electrophoresis and fluorescence detection apparatus has an electromagnetic radiation sensor juxtaposed with a sensing region. The output signal from the electromagnetic radiation sensor is a current signal, and the current signal is converted to a voltage signal. The voltage signal is summed with a programmable offset generated by an inexpensive eight-bit D/A converter. The offset signal is selected to establish a lower starting point for the dynamic range of the A/D conversion, and is selected to null some or all of the background electromagnetic radiation level. The summed signal is amplified and integrated in an integrator. The integrator is switchable under program control. The integrator is switched on for long and short intervals. The short intervals permit sensing over a dynamic range accommodating very high levels of fluorescence; very high peaks may be measured and features of the peaks distinguished.

Abstract: Circuitry and method for transferring signals from a photoreceiver array to computational circuitry includes parallel transfer amplifiers that receive periodic offset correction and includes DC removal amplifiers. In a first embodiment, each transfer amplifier has a differential circuit that can be switched from a reset mode to a readout mode. In the readout mode, the voltage state at the output is responsive to first and second inputs, with the second input being connected to a source of a reference voltage. In the reset mode, the inputs are both connected to the reference voltage and the output is temporarily connected to a source of a fixed reset voltage. An offset adjustment signal is generated in response to detection of a voltage difference between the reset voltage and the actual voltage state at the output after the output has been disconnected from the source of the reset voltage. A single offset circuit is used to periodically and sequentially refresh the various transfer amplifiers.

Abstract: A solid-state image sensing device has an inverting-amplifier constructed with MOS transistors, which is provided with electrical power through a common output line, and inputs and outputs signals through the common output line. With this configuration, a supply line conventionally used exclusively for supplying electrical power does not pass through a pixel of a solid-state image sensing device, thereby reducing difficulty of manufacturing a fine pixel and making a large aperture area. The inverting-amplifier of this solid-state image sensing device is reset to the same voltage as that of the common output line, and an offset voltage is read out. Thereafter, the electric charge inputted into the inverting-amplifier from a photo-electric converter is inverted and amplified, and the resultant signal is read out. Finally, a difference between the inverted and amplified signal and the offset voltage is obtained and outputted as an image signal.