Sensor including an array of sensor elements and circuitry for individually adapting the sensor elements
First Claim
1. A photo-conductive infrared sensor comprising:
- an array of sensor elements each varying in conductivity in response both to temperature (thermic variation), and to incident photons of infrared light (photonic variation) which is to be measured;
plural adaptation circuits each individually conducting a variable bias current from a source thereof through the respective one of said plural sensor elements, said adaptation circuits each including a resistive element in parallel with a variable-conductance element, said variable-conductance element varying in conductivity in response to a feed back signal to provide a first portion of said bias current resulting from variation of conductivity of said sensor element in response to thermic variation, said resistive element providing a second portion of said bias current resulting from variation of conductivity of said sensor element in response to said photonic variation, and said resistive element also providing a first signal in response to voltage drop there across, each adaptation circuit including a multi-position switch in one position thereof supplying said first signal to said variable-conductance element as said feed back signal.
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Accused Products
Abstract
An infrared sensor includes a linear array of plural photoconductive sensor elements, and a similarly linear multiplexing circuit arranged in side-by-side relation with the linear array of sensor elements. The multiplexing circuit includes a matching plurality of signal input ports, and a wirebond of plural conductors substantially in parallel conducts signals from the plural sensor elements of the array to the respective signal input ports of the multiplexer circuit. The multiplexer circuit includes a matching plurality of adaptation circuits or cells interposed between the respective sensor elements of the array and the input ports of the multiplexing circuit. Each adaptation cell includes a multi-position switch which by its position varies the transfer function of a feed back circuit of the adaptation cell. Plural modes of signal processing for each individual sensor element of the array are provided according to the positions of the multi-position switches of the plural adaptation cells. The sensor includes a microprocessor which allows each sensor element of the array to be operated in a selected one of the plural modes of operation according to the position of the multi-position switch commanded by the microprocessor.
47 Citations
19 Claims
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1. A photo-conductive infrared sensor comprising:
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an array of sensor elements each varying in conductivity in response both to temperature (thermic variation), and to incident photons of infrared light (photonic variation) which is to be measured; plural adaptation circuits each individually conducting a variable bias current from a source thereof through the respective one of said plural sensor elements, said adaptation circuits each including a resistive element in parallel with a variable-conductance element, said variable-conductance element varying in conductivity in response to a feed back signal to provide a first portion of said bias current resulting from variation of conductivity of said sensor element in response to thermic variation, said resistive element providing a second portion of said bias current resulting from variation of conductivity of said sensor element in response to said photonic variation, and said resistive element also providing a first signal in response to voltage drop there across, each adaptation circuit including a multi-position switch in one position thereof supplying said first signal to said variable-conductance element as said feed back signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An infrared sensor comprising:
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an array of photoconductive infrared sensor elements each providing a corresponding one of plural electrical signals indicative of infrared radiation falling thereon; a multiplexing circuit having a like plurality of signal input ports each receiving a respective one of said plural electrical signals and sequentially connecting corresponding signals to an output conductor; and a like plurality of adaptation input cells each conducting an electrical signal from a respective sensor element of said array to a respective one of said input ports of said multiplexer circuit, each adaptation input cell providing a variably-conductive circuit element conducting a bias current flow through the respective sensor element, and an externally-controllable switch which by its position effects a selective variation in the conductivity of said variably-conductive circuit element. - View Dependent Claims (8, 9)
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10. An infrared sensor including an adaptation circuit for extracting an output signal from a variably-conductive infrared sensor element, which infrared sensor element varies in conductivity in response both to changes in temperature and in response to an external infrared electromagnetic radiation stimulus which is to be sensed, said adaptation circuit of said infrared sensor comprising:
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a resistor, a first transistor, and a capacitor mutually connected in parallel between a source of bias current and said sensor element; a second transistor connected in series with said sensor element, and with the parallel combination of said resistor, said first transistor and said capacitor between said bias current source and a ground; a feedback conductor connecting a voltage drop signal from said resistor to a gate of said first transistor and externally of said adaptation circuit as said output signal; a multiposition switch in a first closed position connecting said voltage drop signal from said resistor to said gate of said first transistor. - View Dependent Claims (11, 12, 13, 14)
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15. A photoconductive infrared sensor comprising:
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an array of photoconductive sensor elements each providing a respective output signal in response to infrared light incident thereon; a multiplexer circuit having a like plurality of signal input ports; a like plurality of adaptation cell circuits connecting individual output signals from respective sensor elements of said plurality of sensor elements to respective ones of said plurality of input ports; each adaptation cell circuit of said plurality of adaptation cells including a respective variable feedback loop variation of which varies said output signal from said sensor element, and an externally-controllable multi-position switch varying said feedback loop in dependence upon the position of said switch. - View Dependent Claims (16, 17, 18, 19)
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Specification