Abstract: A compound infrared detector, having a thermopile detector which is constructed on one face of a pyroelectric insulating thin film and a pyroelectric detector which is constructed by installing electrodes on both faces of the insulating thin film in opposite relationship to an infrared ray responsive portion thereof.The compound infrared detector of the present invention can function both as a pyroelectric detector and as a thermopile detector. In addition, the pyroelectric detector and the thermopile detector can be installed on the identical focus of the identical optical system because they have a common infrared ray responsive portion and as a result thereof, the number of detectors and also the number of optical adjusting means and optical parts can be reduced relative to those used in the prior case when two detectors are used; that is, the mutual compensation effect of both kinds of detectors can be inexpensively attained.

Abstract: A dual pyroelectric crystal sensor suitable for infrared intruder alarms and the like having two separate closely spaced identical pyroelectric crystal detectors connected in parallel opposition. The sensor includes a single ended field effect transistor amplifier with the entire sensor encapsulated in a TO-5 can. The two crystals each have one end cemented to a ceramic substrate in a cantilevered fashion, permitting shock or vibration to affect each crystal equally. Therefore, voltages due to the piezoelectric responses of the crystals are equal and cancel. If both crystals are irradiated by a common heat source, the pyroelectric generated voltages will cancel. If either crystal is irradiated separately, an output voltage will be produced.

Abstract: A shield for limiting the radiation received by individual detectors within a detector array of an electromagnetic radiation detection system to the radiation provided to the detectors by the optics of the system. The shield comprises a member of etchable glass having apertures formed therein, the position of the aperture edges being in predetermined relation to the edges of the detectors for shielding the detectors from electromagnetic radiation generated outside the field of view of the optics.

Abstract: In order to reduce microphony due to the piezoelectric nature of a pyroelectric element (9) in a pyroelectric detector, the detector comprises one or more flexible films resiliently supporting the element (9) and two electrical connections thereto each comprising an electrically conductive layer (6,8) on the film(s). There are suitably two films with the element (9) therebetween. The films are secured to one another around the element (9) by an adhesive, thereby urging the films against the element (9) to hold it in position and maintain the electrical connections.

Abstract: A fire or explosion detection system for discriminating between radiation produced by a source of fire or explosion to be detected (e.g. a hydrocarbon fire) and radiation produced by a source not to be detected (e.g. an incendiary ammunition and or pyrophoric reaction between an aircraft skin and an inert round) is disclosed. The radiation detectors are respectively responsive to the intensity of radiation in narrow wavelength bands at 0.96 and 4.4 microns. Two threshold units produce respective electrical signals only when the outputs of the detectors exceed respective predetermined values. In addition, a rate of rise unit produces an electrical signal only when the rate of rise of the output of one of the detectors exceeds a predetermined value. An output gate receives these three electrical signals and produces an output to a delay unit which in turn produces a fire or explosion indicating output only when the output of the gate continuously exists for at least a predetermined period of time.

Abstract: A pyrodetector is disclosed which has a sharply limited directional range of detection sensitivity for the detection of a body entering into its directional range at a distance from the detector, the body having a temperature which is different from that of its environment. A concave mirror for focusing thermal radiation emanating from the body is provided and a pyroelectric sensor positioned at a focus of the mirror is also provided and formed as a flat body consisting of an electrically non-conductive material and with a pair of electrodes. A cover transmissive to the incident thermal radiation is provided for protecting the sensor element against damage and air drafts. At least one further sensor element similar to the first sensor element and with essentially the same heating time constant is also provided and arranged adjacent to the first sensor element but beyond the mirror focus.

Abstract: The thermal gain sensor detects, by a simplified method, the direction of net energy flow through a fluid-separation barrier (window). In particular, the sensor determines a balance point above which the radiant energy (solar, microwave, X-ray, etc.) gained through the barrier exceeds the energy lost through the barrier from the combined effects of convection and conduction.One application of the thermal gain sensor pertains to a solar energy collector or solar heated room. The sensor controls movable insulation panels or curtains which reduce the energy flow through the collector window (barrier) when the energy flow is in the wrong direction. The sensor may be used to either maximize or minimize the energy in the collector or room.The sensor simulates the absorptivity and convection loss of the controlled environment by means of an insulated, darkened disk slightly spaced from the barrier surface.

Abstract: A pyroelectric detector comprising a body of pyroelectric material having a front surface for receiving radiation, a rear surface, a relatively thin coating of radiation absorbing and transmitting and electrically conducting material applied to the entire front surface, and a pair of relatively thicker areas of radiation reflecting and electrically conducting material applied to the rear surface in spaced-apart relation. Two heat sensitive charge generators are defined in the two regions of the pyroelectric body between the coating on the front surface and the two areas on the rear surface, and output electrical leads are attached to the two areas on the rear surface. When radiation is absorbed by either of the heat sensitive charge generators, an electrical current flows in a circuit connected to the output leads thereby providing an indication of the radiation.

Abstract: A system for discriminating between radiation produced by a source of fire or explosion to be detected and that produced by a source not to be detected, comprises two radiation detectors 10, 12 respectively responsive to the intensity of radiation in different and spaced apart narrow wavelength bands. A rate of rise unit 22 and a threshold unit 24 responsive to detector 12 produce signals of a first binary type when the rate of, and the value of, the radiation intensity exceed predetermined values. A ratio unit 16 measures the ratio of the intensities of the radiation received by the two detectors and produces a signal of the opposite binary type when the ratio indicates that the source of radiation is a fire or explosion to which the system is not to respond. An AND gate 36 produces a fire and explosion indicating output only when the signals of the first type exist in the absence of the signal of the opposite type.

Abstract: An infrared charge transfer device (CTD) imaging system is disclosed which includes an optic system for focusing infrared energy emanating from a scene, a detector matrix for receiving the focused infrared energy and converting it to electrical signals representative of the intensity of the infrared energy, and a video processor for processing the electrical signals into video signals. The detector matrix of the system is a plurality of IR detector cells arranged in rows and columns. Each detector cell includes a substrate of semiconductor material, an integrating electrode, a drain electrode, a transfer electrode and insulating layers. The integrating electrode is centrally disposed with respect to the drain and transfer electrodes with the integrating electrode in a spaced relationship with the drain electrode. The integrating and drain electrodes form first level MIS electrodes on the semiconductor substrate.

Abstract: A system for discriminating between radiation produced by a source of fire or explosion to be detected and radiation produced by a source not to be detected comprises two radiation detectors respectively responsive to the intensity of radiation in different wavelength bands to product respective electrical outputs, one band being relatively broad and including the other which is relatively narrow. A rate of rise unit and a threshold unit responsive to the broad band detector produce signals of one binary type when the rate of rise of, and the value of, the intensity of the radiation received by that detector exceed predetermined values. A ratio unit measures the ratio of the intensities of the radiation respectively received by both detectors and produces a signal of the opposite binary type when the ratio indicates that the source of the radiation is a fire or explosion to which the system is not to respond.

Abstract: A mounting means for apparatus useful for processing infrared signals including a pyroelectric detector array with a plurality of detector elements, a plurality of electrically conductive epoxy polymer mounting means having two ends and attached at one end to the detector array to provide individual electrical contact for each of the detector elements. The apparatus further includes circuit means attached to the other end of the mounting means for processing electrical signals from the array.

Abstract: A monolithic imager utilizing a plurality of detector cells for detecting the presence of radiation and producing a two dimensional mapping thereof. The detector cells are arrayed in a matrix having a square center surrounded by a number of polygonal rings so that a relatively high resolution mapping of detected radiation is achieved at the center of the imager.

Abstract: As CCD circuit for restoring to a common DC level, data received from a plurality of detector channels of a scanned array so as to overcome the effect of variations in detector parameters and other non-uniformities in the circuit. The DC correction value is established during retrace time by storing a representative time integrated data charge packet when energy from a cold reference surface is being applied to the detectors. During the scan time of the field of view by the detectors the representative charge packet is utilized to provide a DC restoration or correction charge to each data charge packet received from the detectors. The system thus standardizes to a common DC level, the output data from a plurality of channels.

Abstract: An infrared charge transfer device (CTD) imager system is disclosed which includes an optic system, a charge transfer device detector matrix and a signal processor. The optic system focuses infrared energy from a scene onto the detector matrix. The detector matrix produces electrical signals representative of the impinging energy and the signal processor processes the electrical signals into video signals. The CTD detector matrix comprises a plurality of charge injection devices (CID). Each CID has an IR sensitive area, and two metal/insulator/semiconductor gate electrodes surrounded by a field plate. One, a column gate electrode, is centrally located within the IR sensitive area and the other, a row gate electrode, surrounds the column gate electrode.

Abstract: The target board has an array of discs calorineters spread around the surface to receive the laser energy. The energy striking a disc is sensed by a pair of thermal leads connected to the back side of the disc and the voltage cross the lead is amplified and sent to a recording system.

Abstract: A circuit for use with sensors for providing background subtraction of signals below a predetermined frequency is described incorporating a first transistor for providing a zero to low frequency path and a second transistor or charge coupled device for providing a desired signal path wherein the g.sub.m of the first transistor is large compared to the g.sub.m of the second transistor or CCD device and the first transistor transconductance decreases at frequencies above the time constant determined by the gate capacitance of the first transistor and a resistor in series with the gate.The invention overcomes the problem of large signals in relation to a desired signal during sensing of radiant energy such as infrared. In particular, large background signals tend to saturate signal storage shift registers during time delay integration or just time integration.

Abstract: Electrical signals delivered by detectors at the surface of a first high-capacitance insulating layer which provides a separation between a first array of metallic electrodes and the detectors are collected by the electrodes by capacitive coupling. The first array of electrodes is electrically connected to a second array of electrodes having smaller dimensions. The two arrays are separated by a second insulating layer and the second array is located at the interface between the second insulating layer and the oxide layer which covers the semiconductor readout substrate.

Abstract: Disclosed is a parallel/series infrared scanner for detecting thermal images. "N" infrared detecting elements are arranged in series to scan a single portion of an I.R. image. Adjacent portions of the I.R. image are scanned by additional elements also arranged in series but parallel to the "N" series of elements. The specific detector elements can be selectively activated in order to compensate for disuniformity among detectors in the series. Thus, it is unnecessary to utilize precisely identical infrared detector elements because the number of activated elements in a single series can be adjusted to provide a uniform output which is precisely matched to the output of the other series of detectors.

Abstract: A physical quantity such as temperature, infrared radiation or smoke is detected by means of a conversion device for emitting an alarm signal whose amplitude is representative of the intensity of the physical quantity. The detector comprises a unit for measuring relative variations of the signal in time, for comparing them with a preset threshold level and for actuating the alarm when they exceed the threshold level.

Abstract: Automatic responsivity control for an array of infrared photodetectors is provided without additional hardware such as a beam chopper or a reference object of known irradiance. The requisite modulated reference signal is provided instead by uniformly modulating the bias voltage applied to each of the plurality of photodetectors in the array. Photodetectors having different responsivities respond to the same bias modulation differently to produce a superimposed sinusoidal component in the photodetector output current which is used to compensate for differences in responsivities of the individual photodetectors.

Abstract: A shield or opaque covering for reducing blooming at low input levels in -dimensional charge-injection devices. Two-dimensional charge-injection devices include X-Y aligned detector elements in which each detector element includes a y-electrode portion and a x-electrode portion, each in the same alignment. Each of the y-electrode portions in the same vertical column is connected to a common conductor to form separate y-electrode column conductors, one for each column of elements. Each of the x-electrode portions in the same horizontal row is connected to a common conductor thereby forming separate rows of x-electrode conductors, one for each row of elements. During fabrication each of the rows of y-electrode portions is permanently covered with a covering which is opaque to the radiation to be detected whereas each of the x-electrode areas is exposed to the radiations to be detected.

Abstract: An infrared detector assembly comprising a substrate of suitable material such as sapphire, an infrared detector array attached to the substrate, a cold shield attached to the detector array, and an optical microphonics filter attached to the cold shield is disclosed. The optical microphonics filter includes a substrate of material having its major surfaces coated with layers of thin film coatings for passing a preselected frequency band, and a metalization for reflecting spurious energy impinging thereon thereby shielding the filter's substrate and coatings therefrom.

Abstract: The invention provides a surveillance system comprising a number of infra-red detectors in an array, each of which is arranged to view a different portion of a field of view in order to discriminate between targets of different veiwed sizes at a target range. Each infra-red detector has in its output a threshold detector, the threshold level of which is determined by the mean output levels of adjacent detectors in the array. In a preferred example, for a given threshold detector in the output of a given infra-red detector the mean output level of two adjacent, but not immediately adjacent, infra-red detectors on one side and two adjacent, but not immediately adjacent detectors, on the other side are summed and the result divided by four to provide the reference level for the threshold detector concerned.

Abstract: An infrared analyzer is described which analyzes constituents of a sample. The sample and/or reference signals are synchronously averaged to provide unisonous sample and reference values. This processing eliminates drift and signal noise from the measurements, thus providing a more sensitive and accurate characterization of the constituents of the sample.

Abstract: An infrared radiation intruder detection system is disclosed which employs a unique pyroelectric detector array. The array comprises a pyroelectric plastic film having electrodes arranged on opposing surfaces to define a plurality of heat-sensitive capacitors connected in parallel. According to a preferred embodiment, the film of selected detector elements is poled to a polarity opposite that of the other elements to cause internal cancellation of signals due to events which affect an even number of detectors simultaneously.

Abstract: An optical system for infrared detection in the 3 to 14 micrometer region comprising: a viewing aspheric corrector, a spherical mirror having a focal length, said spherical mirror being positioned to receive the light passed by said viewing aspheric corrector, a plurality of detector cells comprising an array thereof sufficient to vertically scan an image to provide high resolution and positioned to lie at the focal length of said optical system behind a narrow pass spectral filter, said detector cells being adapted to produce an electrical signal responsive to the infrared radiation detected thereby, means for moving the system field of view in azimuth, a multiplexer to scan the array of cells and deliver their signals sequentially to an image display, and a cryogenic cooling system for cooling the filter and the cells.

Abstract: An attitude reference system which uses microwave radiometry to sense the orientation of a vehicle. A fundamental fact of microwave radiometry is that more natural energy emanates from the earth than from the sky. The difference in energy, which is directly proportional to temperature, can be used to estimate attitudinal position. Microwave antennas mounted on an escape vehicle, such as an aircraft ejection seat, receive energy from different directions in a base plane and from a direction perpendicular to the base plane. Vehicle orientation relative to the earth is discerned by comparing the sensed radiometric temperature received from each antenna direction, and seat guidance equipment is programmed to steer the seat in a predefined direction based upon the radiometrically sensed orientation.

Abstract: An improved Dewar assembly for infrared detectors is disclosed. Vacuum tight feed-throughs are partially embedded in the inner flask with exposed portions on both sides of a vacuum seal.

Abstract: An optical scanning system wherein infrared energy radiating from an object is directed to a Porro prism, such Porro prism being rotatable about the boresight axis of the optical scanning system so that the image of the object rotates, in the image plane of such system about its boresight axis, at an angular rate twice that of the Porro prism. A linear array of infrared detector elements is disposed in the image plane radially from the boresight axis of the scanning system. The angular deviation of the object from the boresight axis of the scanning system is measured by determining: (1) the angular position of the Porro prism when one, or more, of the infrared detector elements in the linear array is energized; and (2) which one, or ones, of such elements is energized.

Abstract: An illustrative embodiment shows infrared radiation divided into two beams which impinge on respective detectors via respective stationary filters, so as to provide measures of two constituents of a mixture of gases used for mixed anaesthesia. The same angled mirrors which provide the measurement beams may also be reflective on their sides toward the infrared source to provide reference beams to the filters and detectors such that the detectors may alternately sense the measurement and reference beams with the aid of beam interrupters.

Abstract: A circuit for an infrared intrusion detector comprising a plurality of receiving directions or regions which are separated from one another and a radiation receiver, at the output of which there appears an electrical signal corresponding to the infrared radiation which is absorbed by all of the receiving directions or regions. The circuit is structured such that an alarm signal is delivered when the received infrared radiation both ascends in a predetermined manner as well as descends in a predetermined manner within a given delay time.

Abstract: A radiation detector having at least one radiation sensitive element with more than two electrical contacts. The effects of noise occurring between pairs of contacts are substantially eliminated by multiplying at least two partial signals appearing between two of the contacts. The detector is particularly suitable for use as a passive infrared detector and as a flame detector.

Abstract: A radiation scanning-detecting and processing system having a composite detector arrangement including detector elements having mutually different sensitive areas. An information processing system coupled to such detector arrangement is effective in response to certain operational parameters to selectively vary the relative contributions of detector elements having different sensitive areas to the overall signal derived from all detector elements in combination.

Abstract: A secondary detection system for utilization with a security validation apparatus wherein a sensing is made of the amount of light reflected from a given area of a paper security. Fundamentally, the invention consists of an infrared lamp or other emission source casting light through a tunnel and upon a highly reflective but partially transmissive surface. The reflective surface directs a large portion of the light onto the paper security. A first solar cell is provided in juxtaposition to the reflective surface for sensing the amount of light reflected onto the paper while a second solar cell is provided for receiving and sensing that quantity of light reflected back from the paper. A comparator circuit is interconnected between the two solar cells to determine the validity of the paper security on the basis of the percentage of light incident to the paper which is reflected therefrom.

Abstract: Temperature profiles of objects having large areas are measured and displayed by providing a plurality of radiometric sensors, each sensor having an established field of view and being directed toward the object whose temperature is being measured. Outputs of the sensors are processed to provide maximum sensitivity within a specified temperature range and little or no sensitivity outside of the specified range. Within a specified temperature range the temperature scale is divided into a number of increments, the number of said increments dependent on the desired degree of resolution of measurement. The processed and expanded output of each of the radiometric sensors is electronically compared and categorized into the selected divisions of the specified temperature range. Electrical signals derived from this comparison are provided to columnar displays associated with each radiometric sensor whereby the range of temperature is displayed and the output of each radiometric sensor is indicated.

Abstract: An infrared acquisition device is described which surveys a relatively large field of view in which an emissive target is likely to appear. An optical system focuses an image of the target onto a mosaic of separate detectors arranged in concentric fields and so arranged that the appearance of the target image on the outer or peripheral field will reposition the optical system so as to move the image onto the inner or central field. Chopper means are provided for modulating the signal for processing into servo control signals and also for discriminating against background radiation.

Abstract: A discriminating fire sensor includes detecting means which discriminates between hydrocarbon fires desired to be detected and high-energy exploding rounds of ammunition without causing a hydrocarbon fire. Also, the system distinguishes between a hydrocarbon fire desired to be detected and ambient radiation in order to prevent false alarms. Circuit means coupled to the detecting means provide an output control signal for the activation of a fire suppressant only when a hydrocarbon fire is detected having predetermined properties to exclude false alarms.

Abstract: A two-dimensional, AC-coupled, wide dynamic range, mosaic infrared sensor is realized by apparatus that divides incoming infrared radiation into two equal beams. Each beam is received with or without optical concentration by an infrared detector array consisting of a multiplicity of spaced, parallel columns of electrically insulated, independently wired infrared detector elements. The detector element column widths of each detector array are substantially equal to the intercolumn spaces of the other detector array and the columns of each are optically aligned with the intercolumn spaces of the other.

Abstract: A system for eliminating background signals in chopped infrared measuring systems employs operational amplifier principles for subtracting a reference signal of proper amplitude, phase and frequency from the background-plus-signal radiation. The output is converted to a dc voltage level directly related to incident flux.

Abstract: This invention relates to an improved infrared analyzer, wherein the total radiant energy reaching the detector is maintained at a constant value independently from the aging of the source of radiant energy or the soiling of the sample cell. According to the invention, the improved infrared analyzer comprises a comparator, whose outlet feeds the radiant energy source and whose inlets receive a reference signal of constant value and, respectively, a signal which varies as a function of the total radiant energy received and measured by the detector.

Abstract: A device for controlling the level in a container of a liquid which will emit infra-red rays and particularly molten metal is described. The device comprises a housing, at least one longitudinal window at one end of the housing and arranged so that when in use it will overlook an edge of a container containing the liquid, the level of which is to be controlled; and at least one photo-element for sending out an electrical signal through said window to said liquid; at least one second window which is substantially punctiform and which overlooks a substantially constant portion of the liquid in the container and within the vertical field of adjustment; and a second photo-element in cooperation with the second window for sending out a pilot signal, and circuitry to correct the signal indicating the liquid level of the container by means of the pilot signal and for amplifying and comparing the signal coming from the correction circuit.

Abstract: A method and apparatus are disclosed for monitoring parameters of a film or coating by directing a beam of optical radiation at a film supported on a metal substrate at an angle to the film so as to plane polarize any radiation transmitted through the film, reflecting a portion of the radiation from the interface between the film and substrate, transmitting the radiation through a polarizing medium before and/or after it has been transmitted through the film to block any component of radiation other than that which is or will be transmitted through the film, and transducing the radiation reflected from the interface to provide an output signal which is a function of a parameter of the film.

Abstract: Scanning apparatus for scanning a field of view having a multidetector array which traverses the field of view, the detectors of which are sensitive to variations in electromagnetic radiation wherein each detector is a.c. coupled to an amplifier in a respective video channel and at the end of each scan the gains of the amplifiers in the said channels are equalized one with another.

Abstract: The present invention relates to an accumulation mode charge injection device utilizing the extrinsic photoconductivity of a doped semiconductor material to sense infrared radiation. The device is operated at cryostatic temperatures to preclude thermal ionization of the impurity sites and majority carriers are produced by IR photons interacting with these sites. The device utilizes a metal-oxide-semiconductor structure to accumulate the IR photon induced majority carriers at the semiconductor oxide interface under a first bias condition. When the bias is reversed the accumulated charges are injected into an output electrode. The sensor may be used singly or in arrays of similar sensors.

Abstract: An eye-motion operable keyboard-accessory includes light source means for directing a light ray at an eye of an operator, for obtaining a light reflection therefrom, and a plurality of light-responsive sensors selectively actuable by the operator-reflected light ray. The sensors are connected to electrically operable key means disposed on a keyboard for actuation of the former upon the operator-reflected light ray striking one of the light-responsive sensors.

Abstract: Apparatus and method for inspecting hot glass containers by sensing the heat radiation from the bottles. Newly formed glass containers are moved past the apparatus of this invention in a single file immediately after leaving the bottle forming machines. A series of four heat-sensing probes register the heat radiation pattern of containers as they pass by. A logic unit determines if the container is of the proper diameter, standing upright, and has a neck portion that is not significantly inclined from the vertical. Containers which are lying down, two containers stuck together, or containers which have a bent neck portion are rejected.

Abstract: An atomspheric turbulence detection system for use in an aircraft comprising a scanning radiometer for continuously providing a plurality of independent and distinct temperature measurement signals within a given field of view ahead of the aircraft; means for deriving consecutive first signals indicative of the average of all of the temperature measurement signals within the field of view; means for deriving consecutive second signals indicative of the difference between the temperature measurement signals in two vertically displaced regions within the field of view; means for combining the first and second signals to derive consecutive third signals; means for storing consecutively derived third signals for a predetermined period of time and for continuously deriving a fourth signal indicative of the average of the stored third signals; and means for comparing each newly derived third signal with the fourth signal and generating a turbulence warning upon the occurrence of a predetermined difference therebetw

Abstract: An apparatus for detecting the feeding of piled sheets along a sheet feeding path. The apparatus includes a first reflection plate of high reflectivity and a second reflection plate of low reflectivity. Means are provided for irradiating each of the plates with radiant rays. Means are provided for detecting the quantity of radiant rays reflected from each of the plates. Means are coupled to the detecting means for generating a signal indicating piled sheets being fed when the difference between the quantity of reflective rays from the first plate and the quantity of reflective rays from the second plate are below a predetermined level.

Abstract: Disclosed is a fire and explosion detection system wherein long wavelength radiant energy responsive signals are processed in one channel and compared to short wavelength radiant energy responsive signals which are processed in a second channel. When these signals are coincident in response to a fire or explosion of a predetermined threshold magnitude, an output fire suppression signal is generated.