Abstract: An optical radiation detector utilizes a unitary V-shaped or conical reflector element located within an internal cavity of an optically transmissive capped housing to provide a 180.degree. cylindrical swath or 2.pi. steradian hemispherical field-of-view in a compact package. Radiation from a central portion of the field-of-view received into the open top of the reflector is directed by internal reflective surfaces through an apex aperture onto a central sensing element. Radiation from peripheral points of the field-of-view received outside the open top is directed by external reflective surfaces outside the apex aperture onto outer sensing elements. Bandwidth filtering of the sensed radiation is provided either by selection of material for the cap, or by adding an optical filter plate between the reflector and sensing elements. The reflector is attached either to the undersurface of the cap top, or above the filter plate.

Abstract: A medical diagnostic method and apparatus employs differential radiation detection apparatus for remotely detecting temperature differentials between a plurlity of areas on the surface of an object having a plurality of lenses which each focus a beam of radiation from a corresponding area of the body onto a radiation detector in such a way that not more than one field of view reaches the detector at any time.

Abstract: A radiation detector comprising a first pair of flat reflective surfces parallel to one another and connected by a second pair of flat rectangular reflective surfaces converging toward one another so as to form a reflective chamber having a relatively wide opening for the entrance of radiation and a relatively narrow opening defining a region for receiving radiaiton, there being a radiation sensor positioned in the receiving region for detecting fluctuations in levels of radiation received from a plurality of detection zones.

Abstract: An improved optical assembly which provides a panoramic field of view for infrared motion detection. In one form of the invention the optical assembly comprises a spherical section having an inner surface and an outer spherical surface, the outer spherical surface having a radius of curvature centered in a focal region which is suitable for placement of an infrared detector. The inner surface of the spherical section comprises a plurality of circular convex lenses, each lens having an optical axis passing through the focal region. The combination of the outer spherical surface with each circular convex lens forms a biconvex lens having a focal point in the focal region. Radiation received by each biconvex lens from a zone in the field of view is focused in the focal region for sensing by the infrared detector.

Abstract: A pyroelectric sensor circuit arrangement for reducing noise and increasing sensitivity has a main current amplifier with a high feedback resistor connected to receive input from an electrode of a pyroelectric element, and includes a compensation amplifier in a unity gain amplifier configuration connected to a common power source with the main amplifier. The compensation amplifier is connected to discharge transients from the pyroelectric element when electrode voltage exceeds the positive voltage or goes below the negative voltage of the power source. A pair of anti-parallel diode or similar component is connected between the main amplifier input and the compensation amplifier output.

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 dual pyroelectric crystal sensor, connected electrically in series opposition to provide ambient temperature compensation, drives a single ended amplifier. The load resistor for the sensor is a center tapped high megohm resistor with the center tap connected to the common electrode connections between the dual crystals to bleed off static charges that build up on the sensor due to the very high impedance of the crystal material.

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 pyroelectric detector comprising a wafer of pyroelectric material, means for collecting electrical charge indicative of energy absorbed by the wafer, electrical means for removing and processing the collected charge, a base defining at least one supporting surface, and a flexible suspension for supporting the wafer in spaced relation to the supporting surface. The suspension includes a plurality of link elements each in the form of a thin metal wire fixed to the supporting surface and to a surface of the wafer and located around the periphery of the wafer. Each link preferably has a shape like an arch with both ends fixed to the supporting surface and the wafer surface fixed to the arch between the ends thereof. The link elements have sufficient strength to hold the wafer in spaced relation to the supporting surface, and the links have sufficient flexibility to absorb shock and vibration forces and to compensate for different coefficients of thermal expansion of said wafer and said supporting surface.

Abstract: A pyroelectric detector comprising a wafer of pyroelectric material, means for collecting electrical charge indicative of energy absorbed by the wafer, electrical means for removing and processing the collected charge, a base defining at least one supporting surface, and a flexible suspension for supporting the wafer in spaced relation to the supporting surface. The suspension includes a plurality of link elements each in the form of a thin metal wire fixed to the supporting surface and to a surface of the wafer and located around the periphery of the wafer. Each link preferably has a shape like an arch with both ends fixed to the supporting surface and the wafer surface fixed to the arch between the ends thereof. The link elements have sufficient strength to hold the wafer in spaced relation to the supporting surface, and the links have sufficient flexibility to absorb shock and vibration forces and to compensate for different coefficients of thermal expansion of said wafer and said supporting surface.