Abstract:
An infrared ray detector includes an array of pixels each including an infrared ray sensitive section having a first thermo-sensitive resistor and an infrared ray non-sensitive section having a second thermo-sensitive resistor. The second thermo-sensitive resistor is covered by an infrared ray reflector film. A pair of visors extending from the first thermo-sensitive resistor overhang the adjacent second thermo-sensitive resistor. A difference between the output signals from the first and second thermo-sensitive resistors is delivered as an output signal which cancels the fluctuation caused by the ambient temperature or Joule heat of the bias current.
Abstract:
The present invention is directed to an uncooled, infrared detector which includes a sensor having an amorphous surface layer containing organic carbon and a high dopant concentration which possesses an improved temperature coefficient of resistivity, as well as improved responsivity, and which may be patterned to form a focal plane array by means of common microlithographic techniques. The present invention is additionally directed to an “ion beam mixing” process for preparing the present infrared sensor.
Abstract:
Visible-blind UV detectors are disclosed comprising an active layer of ZnSTe alloy. The Te composition can be varied to provide good lattice matching depending on the nature of the substrate (eg Si, GaP or GaAs) and a novel structure is provided to give high quantum efficiency. The invention also discloses UV detectors with an active layer of pure ZnS and with an active layer of ZnSSe.
Abstract:
A tuned antenna-coupled infrared detector is made possible by application of a bias voltage in the range of a few hundred millivolts. The use of first and second antenna arms connected to the detector makes possible polarization tuning which eliminates the need for bulk-optical polarization filters. An alternative tuned detector is one in which the antenna is frequency tuned by a capacitative device to make the detector particularly responsive to 8 um to 12 um infrared radiation. When integrated into focal plane arrays, these detectors can be used in remote-sensing systems to facilitate enhanced image recognition, feature extraction and image-clutter removal. One preferred version of the polarization tuned antenna has longitudinal metal antenna arms extending outward from an infrared(IR) sensor in a spiral pattern, with polarization tuning devices connected between the antenna arms, and a voltage for controlling the polarization tuning devices, wherein the polarization tuning devices enable real-time control of current distribution in the arms. For the frequency tuned sensors, the embodiment is preferably a microstrip antenna coupled to a bolometer wherein the sensor has a tunable response accomplished by use of a single substrate voltage on a separate capacitative device. The infrared(IR) sensors can be tunnel diodes, schottky diodes, photovoltaics, photoconductors, bolometers and pyroelectrics. Application areas can include earth-resource mapping, pollution monitoring, and general surveillance.
Abstract:
Methods and apparatus for compensating a radiation sensor for temperature variations of the sensor. In one example, the radiation sensor is a thermal sensor having at least one property that varies as a function of temperature. The thermal sensor outputs signals based on thermal radiation of interest from a particular radiating body in its view. These signals may contain significant undesirable components due in part to changes in temperature of the sensor itself. Methods and apparatus of the invention compensate the sensor for temperature variations of the sensor that are not due to the radiation of interest, so as to significantly reduce undesirable components in the instantaneous signals output by the sensor. In one example, this is accomplished without thermally stabilizing the sensor itself (i.e., dynamic temperature compensation). In another example, the sensor is thermally stabilized selectively at various predetermined temperatures as a function of the ambient temperature in the proximity of the sensor.
Abstract:
A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector comprising a plurality of closely-packed detection modules. Each detection module comprises a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold. The fall-through circuit searches for the next detection element and associated channel having a valid event. The signal processor performs diagnostics, gain normalization, and response efficiency normalization functions. The data acquisition system controls the acquisition and processing of data received from the conditioning and processing channels, produces image data based upon the data in a format that is compatible with existing imaging cameras, and transmits the data to the image processing computer. The image processing computer formulates images based upon the processed signals and displays the formulated images on a display device.
Abstract:
Radiation detector arrays are provided that include one or more thermal-type displaceable elements having reduced thickness without compromising mechanical strength or sensitivity of the displaceable elements to incident radiation. An exemplary displaceable element includes first and second membrane layers made of materials having different coefficients of thermal expansion. The layers are supported relative to a substrate by a leg. The displaceable element can also serve as an absorbing member for the incident radiation to be detected. Each element can also include a reflector of signal light. When the displaceable element incident radiation (such as infrared radiation) to be detected, it undergoes heating which bends the element. Displacement of the element is detected as a change in signal light or as a change in capacitance. If the displaceable member includes a signal-light reflector, the reflector includes a planar portion including “dropped” edges serving to strengthen the planar portion and allow the thickness of the planar portion to be reduced.
Abstract:
Infrared solid-state imaging elements include an infrared absorbing section formed as to correspond to each pixel aligned in a two-dimensional pattern for absorbing incident infrared radiation and converting the same into heat. A temperature detector section is formed as to correspond to each pixel on a semiconductor substrate and are arranged of a plurality of serially connected silicon pn junction diodes that are biased in a forward direction. A hollow section is formed on each region on which the temperature detector section is formed on the semiconductor substrate. Supporting mechanisms are arranged of materials exhibiting large thermal resistance and which support the temperature detector portion above the hollow section on the semiconductor substrate. A joint column thermally couples the infrared absorbing section and the temperature detector section.
Abstract:
A small array of antenna-coupled infrared bolometer detectors is connected in parallel. This small array is suitable as an individual area-receiving pixel of an infrared focal plane array. These pixels will have better coupling efficiency to extended sources than are possible with individual antenna-coupled sensors, which have a spatial response on the order of one wavelength in dimension. This pixel can be used to provide the advantages of antenna-coupled IR sensors (e.g., fast response, wavelength tuning, and polarization tuning) while increasing the collection efficiency of the sensors to non-laser sources. When integrated into focal plane arrays, these detectors can be used in remote-sensing systems to facilitate enhanced image recognition, feature extraction and image-clutter removal. A preferred version of the pixel forming the focal plane array antenna has a plurality of two parallel longitudinal metal antenna arms extending outward and opposite from an infrared (IR) bolometer sensor to separate parallel contact pads connected in turn to a means for receiving the output from said antenna. Application areas can include earth-resource mapping, pollution monitoring, and general surveillance.
Abstract:
An infrared photosensitive area is constituted by an infrared ray absorbing part that is heated by infrared rays, a thermal detector that detects the temperature change of the infrared ray absorbing part, and electrodes that are electrically connected to the thermal detector. The infrared photosensitive area is held up above one surface of a substrate by supports. The electrodes of the infrared photosensitive area are electrically connected to contact pads on the substrate by wiring material that constitutes the support. A shield projects from portions of the infrared ray absorbing part other than portions that correspond to the electrodes. The contact pads of the substrate and the surfaces of the electrodes and the supports that are directed away from the substrate are covered by the shield with an interposed space. This configuration enables an increase in the fill factor of the picture elements of the thermal infrared detector and enables greater absorption of infrared light.