Special Photocell Or Electron Tube Circuits Patents (Class 250/214R)
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Patent number: 5693934Abstract: Photocurrents outputted by photo detecting circuits (1.sub.1 to 1.sub.n) disposed in first current paths (2.sub.1 to 2.sub.n) are amplified by current amplifying means (3.sub.1 to 3.sub.n) disposed in the first current paths (2.sub.1 to 2.sub.n), respectively. The output currents from the plurality of current amplifying means (3.sub.1 to 3.sub.n) are converted into voltage all by one current-voltage converting means (5). The current amplifying means (3.sub.1 to 3.sub.n) are turned on or off by control signals (3.sub.1S to 3.sub.nS), and therefore the luminance detecting circuit amplifies the current of the required photo detecting element only, and outputs into the current-voltage converting means (5).Type: GrantFiled: December 27, 1995Date of Patent: December 2, 1997Assignees: Mitsubishi Denki Kabushiki Kaisha, Mitsubishi Electric Engineering Co., Ltd.Inventors: Tatsuya Hohmoto, Hiroshi Murakami, Kunihiko Karasawa, Hideo Hara
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Patent number: 5691532Abstract: A means and method of photonic heterodyning wherein at least one photonic beam set having fundamental frequencies to be heterodyned is used to produce a dynamic interference image that is projected onto an image component separator. Energy from selected portions of the dynamic image is separated into at least one output. Energy components within the dynamic image move relative to the separating locations as determined by the fundamental input frequencies. This causes intermodulation of the input signals and the development of energy at the sideband frequencies in the output(s). Special Interference is also used to provide amplified photonic heterodyning.Type: GrantFiled: September 17, 1996Date of Patent: November 25, 1997Inventor: John N. Hait
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Patent number: 5684295Abstract: A solid state image pickup device which performs optical measurement achieving high signal to noise ratio by separating light to be measured from unnecessary noise components comprises a photosensitive unit comprising a photoelectric converting function, a first integrator for either integrating or not integrating a signal generated on the photosensitive unit in a first capacitor connected between an input and output thereof by a first reset signal, a second integrator for either integrating or not integrating a signal in a third capacitor by a second reset signal, a switching device and a second capacitor connected in series between an output of the first integrator and an input of the second integrator, a counter circuit comprising a counting up function and a counting down function, and a timing control circuit for prior to the measurement of the light to be measured, making the first integrator to perform integration by controlling the first reset signal, setting the second integrator in non-integration sType: GrantFiled: April 11, 1995Date of Patent: November 4, 1997Assignee: Hamamatsu Photonics K.K.Inventor: Seiichiro Mizuno
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Patent number: 5656806Abstract: Disclosed is a photodetector comprising at least one photosensitive diode and at least one read circuit enabling the charges generated by photoelectric effect in said diode to be converted into a voltage information element sampled by a switch, wherein said photosensitive diode has a first terminal connected to the gate and to the drain of a first transistor and a second terminal connected to the source of said first transistor and to the ground of said photodetector, wherein a second transistor with dimensions proportional to those of said first transistor is mounted as a current mirror with respect to said first transistor and wherein an integration capacitor is connected to the drain of said second transistor so as to collect said voltage information element at its terminals.Type: GrantFiled: July 10, 1995Date of Patent: August 12, 1997Assignee: Thomson-CSF Semiconducteurs SpecifiquesInventor: Pierre Dautriche
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Patent number: 5654538Abstract: An array of pairs of photodetector elements is provided, where each pair intercepts a set of angularly separated light beams for each pixel, and an array of electrical logic circuits coupled to the photodetector elements, each change the polarization state of liquid crystal pixel SLM portions adjacent thereto, depending upon the intensity and presence of the light beams in each set of light beams. Thus, various Boolean logic functions may be performed at very high speeds without the need for numerous input and output electrical data transmission connections to and from the processor board supporting the SLM. This operation is facilitated by an array of microlenses affixed to the SLM for maintaining the separation of the write beams and readout beam of each set of light beams for each pixel.Type: GrantFiled: October 27, 1995Date of Patent: August 5, 1997Assignee: The United States of America as represented by the Secretary of the Air ForceInventor: Jonathan S. Kane
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Patent number: 5654794Abstract: A portable flash tube intensity monitoring system which includes: an internal power supply; a human eye spectral response photodiode for producing analog signals, each of which is directly proportional to the intensity of each flash from the flash tube; electronics for converting each of the analog signals to a digital time function proportional to the intensity of the corresponding flash; electronics, including a microprocessor, for monitoring the digital time function, for flagging a time function which is below a preselected minimum, for communicating status signals to a localized operator display when the time function is below the preselected minimum, and for testing of an internal power source; a fixed distance indicator which allows accurate measurement from a remote coordinate location; and an operator display. The monitoring system is preferably integrally formed for ease of use and portability.Type: GrantFiled: January 13, 1995Date of Patent: August 5, 1997Assignee: Devore AviationInventors: Robert E. Rutter, Timothy Towne Hewit
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Patent number: 5633492Abstract: The invention relates to non-contact methods of examining parameters of external actions on various media or objects. Such an action could be of various types, e.g., physical (pressure, heating, electric or magnetic field etc.), chemical (action of various chemical substances and associated reactions: binding, replacement, catalysis etc.), biological (action of microorganisms or viruses on a nutrient medium). The invention can be used in scientific research, technology and environmental monitoring.Type: GrantFiled: April 17, 1995Date of Patent: May 27, 1997Assignee: Ceram Optec Industries, Inc.Inventors: Petr Nikitin, Anatolii Beloglazov
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Patent number: 5625182Abstract: A light sensor comprises two light sensitive areas that are shaped to physically compensate for the decrease in light intensity resulting from movement of a movable object in which an aperture is formed. Movement of the aperture causes the light passing through the aperture to have a decreased circumscribed angle that results in a decrease of light intensity impinging on a light sensitive component. In order to avoid the nonlinearity that can result from the decrease in light intensity as a function of the physical position of a movable object being sensed, the light sensitive areas are tapered by selecting the width of the light sensitive area as a function of the distance from a reference line. The light sensitive areas are tapered by arranging the edges of the areas so that the minimum width of each of two light sensitive areas are abutting each other at the reference line and the edges of both light sensitive areas are tapered outward away from each other at positions farther from the reference line.Type: GrantFiled: December 21, 1995Date of Patent: April 29, 1997Assignee: Honeywell Inc.Inventor: James K. Guenter
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Patent number: 5623140Abstract: Disclosed is a nonbiased bistable optical device and a method for fabricating the device, which has a semi-insulating GaAs substrate; a lower mirror having a plurality of reflecting layers which are repeatedly formed on said substrate at least more than twelve times, each of said reflecting layers having a first reflecting film having a first refractive index on said substrate and a second reflecting film a second refractive index different from the first refractive index; a first contact layer formed on the lower mirror; a first buffer layer formed on the first contact layer; a multiple quantum well(MQW) having a plurality of shallow layers which are repeatedly formed, each of said shallow layers having a barrier and a shallow quantum well; a second buffer layer grown on said MQW; and a second contact layer formed on said second buffer layer. The device has an excellent bistablity even without an external applied voltage.Type: GrantFiled: May 25, 1995Date of Patent: April 22, 1997Assignee: Electronics and Telecommunications Research InstituteInventors: Young-Wan Choi, O-Kyun Kwon, El-Hang Lee
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Patent number: 5602385Abstract: A radiation detector which senses two wave bands and a process for making this detector. A first substrate includes a first photodetection element sensitive to a first wave band. A second substrate contains a second photodetection element which is sensitive to a second wave band. The second substrate is transparent to at least the first wave band. The two photodetection elements are positioned facing each other. The substrates are interconnected by conductive spheres.Type: GrantFiled: November 17, 1994Date of Patent: February 11, 1997Assignee: Commissariat a l'Energie AtomiqueInventors: Lydie Mathieu, Francois Marion, Christian Lucas
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Patent number: 5594256Abstract: A high voltage switch for discharging a storage capacitor to increase the voltage across a pockels cell includes a plurality of semi-conductor devices conducted in series with the pockels cell and the capacitor, each of the semiconductor devices having a control input; a plurality of fast, light responsive devices connected to the control input of each semiconductor device of the plurality of semiconductive devices respectively for switching the respective device from a non-conducting state to a conducting state; and a controlled, fast rise time light source optically coupled to all of the fast light responsive devices for simultaneously triggering all of the semi-conductor devices.Type: GrantFiled: January 13, 1995Date of Patent: January 14, 1997Assignee: Clark-MXR, Inc.Inventor: Larry D. Siebert
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Patent number: 5591962Abstract: A photoconductive photodetector to which a modulation voltage signal having a predetermined frequency is applied receives a signal to be measured (I.sub.I) while adjusting the phase of a modulation signal by a phase shifter. A current-to-voltage conversion unit extracts a DC component of a current signal generated at the photoconductive photodetector in correspondence with the intensity of a predetermined frequency component of the signal to be measured (I.sub.I) as a voltage signal. The maximum value of DC voltage values (V.sub.O) obtained in every setting operation of a phase adjustment value is identified. The maximum value corresponds a case in which the modulation voltage signal and the predetermined frequency component of the signal to be measured (I.sub.I) are in phase. The intensity of the predetermined frequency component of the signal to be measured (I.sub.I) is calculated. As a result, a high-speed phenomenon can be measured with a high precision.Type: GrantFiled: July 6, 1995Date of Patent: January 7, 1997Assignee: Hamamatsu Photonics K.K.Inventors: Musubu Koishi, Akira Takeshima, Mitsunori Nishizawa
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Patent number: 5589683Abstract: An optical signal receiver apparatus contains: a photoelectric conversion circuit for receiving an optical signal conveying cyclic timing information, and converting the optical signal into an electrical signal conveying the cyclic timing information; a receiving clock signal extraction circuit for extracting a receiving clock signal indicating the cyclic timing information, from the electrical signal; and a loss-of-clock digital-detection circuit for detecting absence of a change in a digital level of the receiving clock signal.Type: GrantFiled: September 19, 1994Date of Patent: December 31, 1996Assignee: Fujitsu LimitedInventor: Yukako Nakai
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Patent number: 5585623Abstract: An apparatus for detecting a light signal is provided which includes a first frequency source for generating a clock signal having a fixed frequency, a light emitting portion constituted of at least a light emitting element which is driven based on the clock signal of the first frequency source and emits a light signal, and a light receiving portion disposed apart from the light emitting portion.Type: GrantFiled: February 28, 1995Date of Patent: December 17, 1996Assignee: Kabushiki Kaisha TopconInventors: Fumio Ohtomo, Kenichiro Yoshino
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Patent number: 5581077Abstract: The present invention provides a high impedance optical receiver circuit for use in integrated circuits. The receiver circuit consists of an optical detecting device connected to the gate of an FET device and further connected to a diode providing a load impedance. The FET device is connected to a biasing voltage through a biasing resistive element and to a conditioning stage output. The use of a diode to provide a load impedance allows for a smaller and easier to manufacture receiver circuit than would be possible using either a load resistor or a load FET. According to one aspect of the present invention, a digital integrated circuit employing SEED technology incorporates a plurality of diode-loaded receiver in an array of optical receiver circuits to reduce the footprint of the overall SEED circuit array.Type: GrantFiled: July 5, 1994Date of Patent: December 3, 1996Assignee: Lucent Technologies Inc.Inventors: Leo M. Chirovsky, Robert A. Novotny, Ted K. Woodward
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Patent number: 5578815Abstract: A bias circuit for applying a bias voltage to an avalanche photodiode APD2 for detecting light comprises a first diode APD1, a power supply V.sub.H connected to the first diode APD1, for applying a voltage to make the diode in breakdown between an anode and a cathode of the first diode APD1, and a constant voltage circuit V2 connected to the avalanche photodiode APD2 for detecting light, for applying a voltage difference of a breakdown voltage generated between the anode and the cathode of the first diode APD1 minus a constant voltage to the avalanche photodiode. The constant voltage is substantially independent from current flowing in the avalanche photodiode APD2 for detecting light to the avalanche photodiode.Type: GrantFiled: July 8, 1994Date of Patent: November 26, 1996Assignee: Hamamatsu Photonics K.K.Inventors: Shigeki Nakase, Shigeyuki Nakamura, Tsuyoshi Ohta
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Patent number: 5576533Abstract: A circuit for converting solar energy into ac power for supplementary household power has a number of solar photovoltaic cells connected in parallel in groups, with the various groups connected in series (30), and a bridge arrangement of four switching devices (31, 32, 33, 34) each operated to pass current in one direction, with the series-connected groups of cells (30) connected between positive and negative bridge terminals (1, 2), and means for connecting the bridge arms (3, 4) across the primary coils of a transformer (312), with the secondary coils thereof connected to the switching devices to control the phase of passed current, the output at the bridge arms (3, 4) being connectable to the household ac.Type: GrantFiled: October 17, 1994Date of Patent: November 19, 1996Assignee: Premier Global Corporation Ltd.Inventor: Wirojana Tantraporn
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Patent number: 5572074Abstract: A compact photosensor circuit provides automatic intensity range control for machine vision systems. The circuit may be implemented with standard CMOS integrated circuit technology to provide high sensitivity, fully static operation, and automatic exposure control with no moving parts. For each pixel of an imaging array, a photodetector provides an input photocurrent to a corresponding photosensor circuit. The photodetector is connected to provide an output voltage and an input to the gates of a pair of series-connected FETs that act as an attenuator. The attenuator is connected to a biasing source that provides a floor bias voltage. An output of the attenuator is connected to the gate of a third FET connected to the input photocurrent. The output voltage responds as a function of the light intensity at the photodetector while the bias voltage determines the range of light intensity for normal operation of the photosensor circuit.Type: GrantFiled: June 6, 1995Date of Patent: November 5, 1996Assignee: Rockwell International CorporationInventor: David L. Standley
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Patent number: 5565672Abstract: An apparatus and method is provided that improves the dynamic range of an optical transimpedance receiver. The receiver includes a photodetector, a transimpedance front end amplifier and a non-liner feedback. The non-linear feedback means consists of a Schottky diode and shunting the transimpedance resistor with a parasitic capacitor. A lead compensation network is further included in the feedback circuitry to provide stability to the non-linear circuit by advancing the phase shifting of the transimpedance front end by 45 degrees. By stabilizing the frequency off the circuit, the dynamic range is increased from 26.6 dB to 40 dB.Type: GrantFiled: December 30, 1994Date of Patent: October 15, 1996Assignee: Lucent Technologies Inc.Inventors: Stefan A. Siegel, Michael L. Snodgrass
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Patent number: 5563653Abstract: A microchannel plate for an image intensifier tube, the microchannel plate comprising a substrate having an input surface and an output surface and a plurality of channels extending therebetween, each of the channels defining a channel wall, wherein the microchannel plate operates as an electron multiplier, whereby each of the channel walls emits a cascade of electrons in response to an electron entering a respective one of the channels, and a focusing element formed on an output of at least one of the channels for preventing spatial dispersion of the cascade of electrons exiting the output thereof.Type: GrantFiled: April 17, 1995Date of Patent: October 8, 1996Assignee: ITT CorporationInventor: Richard F. Floryan
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Patent number: 5561287Abstract: A semiconductor device comprising a dual photodetector for use in an array to locate points of peak intensities incident upon the array. Each pixel in the array is comprised of a dual photodetector element. An n-type well is located within a p-substrate with highly doped p-contact areas located along the periphery of the n-well at the surface. A metal or polysilicon gate electrode covers the surface between the p-contacts and an applied gate voltage creates an inverted p-channel to form a lateral effect phototransistor. A second photodetector is formed at the junction of the n-well and p-substrate. The second photodetector from each pixel produces a current which is connected to a processing circuit to determine which pixel is the brightest above a designated threshold. All pixels above the threshold are sequentially identified.Type: GrantFiled: September 30, 1994Date of Patent: October 1, 1996Assignee: Board of Regents of the University of ColoradoInventors: Richard M. Turner, Kristina T. Johnson, David A. Jared
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Patent number: 5559331Abstract: A resonant, photoconductive detector for infrared radiation in which a reduced-volume pattern of the photoconductor permits impedance-matching to free space. The photoconductor pattern is a split-ring pattern, typically made of HgCdTe, which is virtually cylindrically symmetric, yielding a non-polarization-sensitive response. The region below the patterned photoconductor is a quarter-wavelength resonant cavity type structure. The ohmic contacts are conductively distanced from one another by use of the split-ring pattern. Spacing dimensions are slightly less than a wavelength for the infrared wavelengths to be absorbed; but ring-width dimensions of the photoconductor are substantially less to effect the volume reduction and the corresponding detectivity and radiation-hardness improvements. The essentially cylindrical isotropic pattern eases fabrication by averaging etching nonuniformities.Type: GrantFiled: December 24, 1990Date of Patent: September 24, 1996Assignee: Northrop Grumman CorporationInventor: Richard C. McKee
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Patent number: 5559340Abstract: A photocoupler includes: a first chip formed with a light emitting element emitting light in response to an input current; and a second chip formed with a light receiving element outputting a current having a magnitude in association with the intensity of the light from the light emitting element, a capacitor formed of a PN-junction for storing charges from the output current from the light receiving element, and a Darlington circuit having the capacitor interposed between the base and emitter thereof, The first and second chips are sealed to form a single photocoupler which is capable of solely effecting phase control.Type: GrantFiled: April 24, 1995Date of Patent: September 24, 1996Assignee: Sharp Kabushiki KaishaInventors: Hideyuki Nakamura, Atsushi Murayama
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Patent number: 5557440Abstract: A method of detecting quadrature signals in a computer input device allows a microprocessor in the input device to perform comparator functions, thus eliminating the need for external comparator circuitry. At least one light-emitting element in the input device emits light pulses, and these light pulses are selectively received by a light-detecting element. A notched encoder wheel separates the light-emitting element from the light-detecting element, allowing various amounts of light to be received by the light-detecting element depending on whether a notch separates the two elements. The microprocessor loads a sample of the output from the light-detecting element: a first sample taken at a selected time value and a second sample taken at twice the selected time value. The second sample is used for quadrature calculations used in determining cursor movement on a video display device. The first sample is retrieved by the microprocessor and determined if it is a digital "1" signal.Type: GrantFiled: January 5, 1994Date of Patent: September 17, 1996Assignee: Microsoft CorporationInventors: Mark T. Hanson, Glade B. Bacon
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Patent number: 5548112Abstract: A photodetecting circuit using an avalanche photodiode of the present invention has an avalanche photodiode, and a bias control means for applying a bias voltage to the avalanche photodiode to drive the avalanche photodiode at a high multiplication factor. The bias control means has a diode having the same temperature dependence of a breakdown voltage as that of the avalanche photodiode, and a control circuit for applying positive and negative potentials with respect to the ground potential between the anode and the cathode of the diode such that the diode is set in a breakdown state at a predetermined current. A positive or negative potential is applied from one of the anode and the cathode of the avalanche photodiode as a bias voltage, and a photocurrent is output from the other terminal of the avalanche photodiode.Type: GrantFiled: December 20, 1994Date of Patent: August 20, 1996Assignee: Hamamatsu Photonics K.K.Inventors: Shigeki Nakase, Shigeyuki Nakamura, Tsuyoshi Ohta
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Patent number: 5532474Abstract: An active quench circuit for interrupting the current flow in an avalanche photodiode (APD) operating in Geiger mode and for resetting the APD. The invention increases the speed of quenching and reduces the time required to bring the APD voltage back to its operating voltage above the breakdown voltage. The circuit includes a small inductor which isolates the reset circuit from the APD during the initial discharge and which provides a current pulse into the APD immediately after the end of the quenching operation to recharge the diode. The reset circuit also includes a diode assembly that increases the speed of the avalanche current pulse and that prevents the circuit from oscillating or latching under certain operating conditions. The circuit presents a low impedance to the APD during during reset, and is much less sensitive to the APD capacitance than prior art circuits.Type: GrantFiled: September 22, 1995Date of Patent: July 2, 1996Assignee: EG&G LimitedInventors: Henri P. E. G. Dautet, Joseph D. P. DesChamps
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Patent number: 5523555Abstract: A photodetector device includes a semiconductive conjugated polymer, such as PPV, arranged between first and second electrode layers having different work functions, a bias circuitry connected to apply a bias voltage between the first and second electrode layers, and a sensing circuitry connected to detect a photocurrent flowing between the first and second electrode layers across the polymer layer as a result of radiation incident on the polymer layer while the bias voltage is applied. The bias voltage is selected in relation to the thickness of the polymer layer.Type: GrantFiled: September 14, 1994Date of Patent: June 4, 1996Assignee: Cambridge Display TechnologyInventors: Richard H. Friend, Andrew B. Holmes, Donal D. C. Bradley, Robert N. Marks
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Patent number: 5519389Abstract: A digital frequency discriminator processes input pulses including first and second time separated input pulses to determine if the frequency of any two sequential pulses lie within a predetermined frequency band with upper and lower frequency limits and that they are received for at least a predetermined period of time. A delay timer is coupled to sense the input pulse stream and operates in a pulse sensing standby mode prior to receipt of the first input pulse. Upon receipt of the first input pulse, the delay timer switches into a time-limited active mode to define a fixed duration delay interval having a duration equal to the period of the upper frequency limit of the frequency band. The delay timer switches back into the pulse sensing standby mode upon completion of the delay interval. A gate timer is coupled to the output of the delay timer and switches from a standby mode into a time-limited active mode upon completion of the delay interval to define a fixed duration bandwidth interval.Type: GrantFiled: March 30, 1992Date of Patent: May 21, 1996Assignee: Tomar Electronics, Inc.Inventors: Richard DeGunther, Thomas R. Sikora
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Patent number: 5498931Abstract: The invention relates to a method for automatic switching and control of lighting to a localized area, the switching of the lighting being dependent on the presence or absence of a person in that localized area and the control of the lighting intensity being dependent on the sensed background level of lighting in that localized area. The invention also relates to a lamp fitting and to an automatic control device for controlling the light output of a light source in a "self managed" and "self controlled" energy saving luminaire.Type: GrantFiled: October 3, 1994Date of Patent: March 12, 1996Assignee: TLG plcInventor: Lou Bedocs
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Patent number: 5495100Abstract: In phase difference detecting method, circuit, and apparatus of the present invention, a voltage signal having a predetermined frequency is applied to a photoconductive light-receiving device, and an optical signal is received by this photoconductive light-receiving device. A current generated upon reception of light and flowing in the photoconductive light-receiving device reflects a product value of the voltage signal and the optical signal, and contains a DC component according to a phase difference between the voltage signal and the component of the optical signal having the same intensity modulation frequency as that of the voltage signal.Type: GrantFiled: July 26, 1994Date of Patent: February 27, 1996Assignee: Hamamatsu Photonics, K.K.Inventor: Akira Takeshima
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Patent number: 5481118Abstract: A brightness sensing circuit for providing a binary electrical signal for indicating whether incident light exceeds a certain brightness. The circuit's light detector is a photodiode, whose output is amplified by a first current mirror. The circuit has a reference current source, whose output is amplified by a second current mirror. Both currents are delivered to a common node, whose voltage level transitions from low to high when the amplified input current exceeds the amplified reference current. This node is connected to the gate input of a CMOS inverter, which provides a binary output.Type: GrantFiled: January 26, 1995Date of Patent: January 2, 1996Assignee: Texas Instruments IncorporatedInventor: Claude E. Tew
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Patent number: 5479208Abstract: An image sensor of charge storage type and a driving method of the image sensor. A light signal from a photosensitive element is read by an amplifier and the read signal is held in a sample hold circuit of a signal detector. Next, a voltage is given from a variable power source to the amplifier and a signal output from the amplifier is compared with the previously held signal in a comparator in the signal detector. The voltage of the variable power source at an equal point where the two signals are coincident with each other in the comparison is read as a true value. Hence, irrespective of dispersion of characteristics of amplifiers, the correct value can be always detected. The influences of the dispersion of the amplifiers, a temperature change and a time-drift of TFT characteristics are removed to improve S/N.Type: GrantFiled: March 22, 1994Date of Patent: December 26, 1995Assignee: NEC CorporationInventor: Fujio Okumura
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Patent number: 5477047Abstract: A direct-contact type image sensor device according to the present invention includes: a light-transmitting substrate having an upper surface and a lower surface; a patterned conductor layer formed over the upper surface of the light-transmitting substrate; a transparent electrically conductive layer formed on the lower surface of the light-transmitting substrate; an image sensor chip mounted face-down on the upper surface of the light-transmitting substrate, with an insulating resin layer being interposed between the image sensor chip and the upper surface of the light-transmitting substrate, the image sensor chip being mounted by a flip-chip-bonding method, a light-interrupting layer provided between the patterned conductor layer and the upper surface of the light-transmitting substrate; and a light-interrupting portion for interrupting a portion of a light beam, the light beam being radiated on an original through the light-transmitting substrate by a light source disposed above the light-transmitting subsType: GrantFiled: October 21, 1993Date of Patent: December 19, 1995Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Masahiro Nakagawa, Tetsuro Nakamura, Shinji Fujiwara, Eiichiro Tanaka
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Patent number: 5466944Abstract: An optically-coupled line receiver that handles multiple-state signals on data communications lines by using a differential circuit at the input.Type: GrantFiled: September 30, 1993Date of Patent: November 14, 1995Assignee: Siemens Components, Inc.Inventor: Robert Krause
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Patent number: 5461225Abstract: In novel sampling methods and apparatus, a repetitive waveform is sampled at a sampling phase which alternates at a phase alternation frequency between a fixed reference phase and a variable phase while changing the variable phase progressively and periodically. The amplitude of a component of the resulting signal at the phase alternation frequency is detected to derive a lower frequency analog of the sampled waveform. The sampling methods and apparatus are particularly useful for electro-optic sampling of very high frequency waveforms in semiconductor devices.Type: GrantFiled: April 29, 1993Date of Patent: October 24, 1995Assignee: Northern Telecom LimitedInventor: Richard D. Clayton
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Patent number: 5451768Abstract: A test system for a photosensitive array includes an on-board test circuit with a single input terminal, wherein the output of the test circuit directly affects the value of a bias charge placed on a selected photodiode. The test circuit enables a quick test for the presence of a desired bias charge when a digital-high voltage is entered on the single input terminal, and also enables a more precise test of photodiode response linearity by application of a predetermined analog voltage to the single input terminal.Type: GrantFiled: November 14, 1994Date of Patent: September 19, 1995Assignee: Xerox CorporationInventors: Paul A. Hosier, Scott L. Tewinkle
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Patent number: 5446277Abstract: Flash tube and lamp monitoring systems. The flash tube intensity monitoring system includes: a human eye spectral response photodiode for producing analog signals, each of which is directly proportional to the intensity of each flash from the flash tube; electronics for converting each of the analog signals to a digital time function proportional to the intensity of the corresponding flash; and electronics, including a microprocessor, for monitoring each of the digital time functions, for flagging those time functions which are below a preselected minimum, and for sending a fault signal when a preselected number of consecutive time functions are below the pre-selected minimum. The monitoring system and flash tube are, preferably, incorporated into single unit for easy installation in the fuselage of an aircraft.Type: GrantFiled: December 27, 1993Date of Patent: August 29, 1995Inventor: Robert E. Rutter
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Patent number: 5432470Abstract: There is disclosed on optoelectronic integrated circuit comprising, a plurality of channels each including an optical receiving device for converting a received optical signal to an electric signal, and an amplifier for amplifying an output signal of the optical receiving device, the channels being integrated on the same semiconductor substrate, electric power source nodes of at least two of the amplifiers of the respective channels being connected to a common electric power source node, and the common electric power source node being connected through a resistor element to an electric source power supply terminal for supplying an electric source power to the channels.Type: GrantFiled: July 29, 1992Date of Patent: July 11, 1995Assignee: Sumitomo Electric Industries, Ltd.Inventor: Goro Sasaki
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Patent number: 5424530Abstract: A solid image pickup device for optical measurement with a high signal to noise ratio. A photosensitive unit includes a first integrator that integrates a signal in a first capacitor connected between an input and output thereof triggered by a first reset signal, a second integrator that integrates a signal in a third capacitor triggered by a second reset signal, a switching device and a second capacitor connecting the output of the first integrator to the input of the second integrator, an up/down counter and a timing control circuit for operating the other elements to achieve proper integration.Type: GrantFiled: March 15, 1994Date of Patent: June 13, 1995Assignee: Hamamatsu Photonics K.K.Inventor: Seiichiro Mizuno
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Patent number: 5401955Abstract: Known optical noise sources are equipped with a light source and an interference filter, optically coupled thereto and based on path length difference, for generating an optical composition signal. If the spectrum of a photodiode to be illuminated with the optical composition signal is to be as flat as possible, said path length difference must be considerably greater than the coherence length of the light source which in present practice leads to disadvantageously large path length differences. By feeding, according to the invention, a noise signal to the light source, the coherence length of the light source decreases, as a result of which it is sufficient to use considerably smaller path length differences.Type: GrantFiled: February 4, 1994Date of Patent: March 28, 1995Assignee: Koninklijke PTT Nederland N.V.Inventor: Robertus F. M. Van Den Brink
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Patent number: 5389778Abstract: A photoelectric conversion circuit which can detect only signal light from applied light, to avoid influence by disturbance light. An anode of a photodiode (1) is grounded and an input end of a tuning circuit (5) is connected to its cathode through an input terminal (3). An output end of the tuning circuit (5) is connected to an output terminal (4) through an amplifier (6). The output terminal (4) is grounded through a load resistor (7). The tuning circuit (5) is tuned with the frequency of signal light included in light (2) which is applied to the photodiode (1). A photoelectric conversion current caused by disturbance light is removed in the tuning circuit (5), so that only a photoelectric conversion current caused by signal light is detected. Switching devices are connected to the photodiode for providing current from the photodiode to the input terminals of the amplifier.Type: GrantFiled: June 17, 1993Date of Patent: February 14, 1995Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Kohji Shinomiya
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Patent number: 5386109Abstract: The present invention relates to an optical receiving pre-amplifier and an optical receiver using the same. The object of the invention is to provide an optical receiving pre-amplifier having an enlarged dynamic range to a large output swing, and an optical receiver having a simplified circuit configuration and a sufficient eye aperture and suitable for a parallel transmission. The optical receiving pre-amplifier includes an input FET 10 with a gate terminal 10a to receive a current signal from a light receiving element and an output FET 12 with the gate terminal 12a connected to the signal terminal 10b of the input FET 10 to amplify and output the current signal to a predetermined voltage signal. A feedback resistor 14 is connected between the gate terminal 10a of the input FET 10 and the output terminal 19 of the output FET 12.Type: GrantFiled: August 17, 1993Date of Patent: January 31, 1995Assignee: Fujitsu LimitedInventors: Tadashi Ikeuchi, Kazuyuki Mori, Nobuhiro Fujimoto
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Patent number: 5384457Abstract: Methods and devices are disclosed for selectively varying the load to a photodetector such as a phototransistor which forms part of a photosource/photodetector pair and for selectively using to advantage or compensating for the parasitic capacitance of the photodetector to permit reductions in power, conversion of fixed signal thresholds to software controlled digital hysteresis, automatic adjustment and compensation for unmatched photosources and associated photodetectors, and adjustment of fixed voltage thresholds.Type: GrantFiled: August 10, 1992Date of Patent: January 24, 1995Assignee: Logitech, Inc.Inventor: Rene Sommer
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Patent number: 5378902Abstract: A number of light sensitive/generating devices are arranged in rows and columns to thereby form an X-Y pixel matrix. All devices are interconnected to a source of operating voltage such that the first device to turn on, i.e., the first device to receive an actuating intensity of light is actuated to thereafter emit light. The current flow through this one activated device causes a voltage drop that prevents any other light sensitive/generating device from turning on. In this way, the pixel that receives the maximum light intensity is identified by its position in the X-Y matrix. Both optical and electrical means are provided to locate the X-Y matrix position of the activated light sensitive/generating device. In an optical embodiment, two orthogonal cylindrical lenses are placed in front of two linear CCDs in order to find the X-Y coordinates of the active light sensitive/generating device.Type: GrantFiled: September 2, 1993Date of Patent: January 3, 1995Assignee: The Regents of the University of ColoradoInventors: Jacques I. Pankove, Christian V. Radehaus
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Patent number: 5365055Abstract: A pulsed-laser radar detection apparatus includes a decision network coupled to a photodetector. The decision network generates an output pulse when a signal detected by the photodetector is a valid signal according to predefined criteria which are implemented in the decision network. An indicator provides an audible or visual indication that a valid signal has been detected. According to the present invention, a Q-switched modulator is provided in the field of view of the photodetector to generate a simulated valid signal. A test switch is connected in series with the modulator such that closing the test switch causes a simulated valid signal to be generated by the modulator.Type: GrantFiled: April 27, 1993Date of Patent: November 15, 1994Assignee: Cincinnati Microwave, Inc.Inventors: Lawrence G. Decker, Janet R. Poston, Edward F. Hume
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Patent number: 5354981Abstract: The disclosure describes one unit cell of a PNPN photoswitch array for an image sensor, including a PNPN light-activated thyristor (LAT), in the form of a two-terminal device, and a load FET. The FET functions as a load and as an on-off switch in series. The output of is a voltage at a first n node that controls the FET switch that connect a voltage-ramp input line to a capacitor and a diode that are connected in parallel. The other side of the diode is the input source of the unit cell that feeds charge into a vertical CCD analog shift register. At the start of a cycle of operation, such as the beginning of a sweep of a radiation beam and prior to a pulse of a target reflection pulse, being directed onto the pnpn photoswitch, the voltage level at the first node is high. At the time when a pulse of radiation is directed onto the photoswitch the first node goes low turning the switching transistor off.Type: GrantFiled: July 14, 1993Date of Patent: October 11, 1994Assignee: Loral Fairchild CorporationInventor: Rudolph H. Dyck
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Patent number: 5352885Abstract: An input signal of a frequency f.sub.0 is supplied to one end of a photodiode. Optical signals of frequencies F.sub.0 and F.sub.0 +.DELTA.F from two light sources are combined by a semitransparent mirror and the resulting interference light is applied to the photodiode. The interference light is converted by the photodiode to an electrical local signal of a frequency .DELTA.F. The electrical local signal and the input signal are frequency mixed in accordance with the nonlinear characteristic of the photodiode and an intermediate-frequency signal of a frequency corresponding to the frequency difference between them is provided at an output terminal.Type: GrantFiled: February 24, 1993Date of Patent: October 4, 1994Assignee: Advantest CorporationInventor: Shoji Niki
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Patent number: 5347120Abstract: A method and apparatus for determining the strength and proximity of a pulsed-laser radar signal is provided. A photodetector detects signals and provides the signals to a decision network. The decision network evaluates the signals and generates an output pulse when a detected signal is a valid signal according to predetermined criteria implemented in the decision network. A processor is coupled to the decision network for counting output pulses. A threat indicator is driven by the processor in proportion to the output pulse count.Type: GrantFiled: April 27, 1993Date of Patent: September 13, 1994Assignee: Cincinnati Microwave, Inc.Inventors: Lawrence G. Decker, Janet R. Poston, Edward F. Hume
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Patent number: 5343032Abstract: An optical receiver, e.g., receiver 10 (FIG. 1), has differential optical input beams and generates an electrical output. The voltage at an electrical node between series-connected optical detector diodes is clamped within a predefined voltage range by series-connected clamping diodes, to prevent the voltage from increasing when consecutive logic one optical input beams are received. Variable bandwidth and low energy dissipation are achieved since the resistors of high input impedance and transimpedance receivers are not required. A second optical receiver, e.g., receiver 20 (FIG. 2) is a monolithic, diode-clamped S-SEED with complementary optical input beams and complementary optical output beams.Type: GrantFiled: April 8, 1993Date of Patent: August 30, 1994Assignee: AT&T Bell LaboratoriesInventors: Leo M. F. Chirovsky, Anthony L. Lentine
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Patent number: H1426Abstract: An apparatus and method for determining the optical power transmitted through an optical fiber. The invention is based on measuring the intensity of the fluorescence produced by a doped segment of an optical fiber. The dopant is selected so that it emits light at a different wavelength than that responsible for producing the fluorescence. The doped segment is of sufficient length and dopant concentration to provide a detectable signal, but short enough to prevent the doped segment from serving as a gain medium, resulting in amplified spontaneous emission and excess fluorescence traveling along the optical fiber. The dopant material is excited by the optical signal carried by the fiber, causing a fluorescence. In the preferred embodiment the intensity of the fluorescence is proportional to the intensity of the propagating light. The signal power is then determined from the intensity of the fluorescence.Type: GrantFiled: October 28, 1992Date of Patent: April 4, 1995Assignee: The United States of America as represented by the United States Department of EnergyInventor: John S. Toeppen