Pyroelectric detector circuits and devices
First Claim
1. A circuit arrangement comprising a radiation detector element of pyroelectric material, field effect transistor amplifier means connected to the detector element to receive an input signal therefrom, said field effect transistor having a gate electrode, at least one ultra-low leakage non-linear device connected in a part of the circuit including the gate electrode of the field effect transistor amplifier means and the detector element, said non-linear device serving to limit the excursion in one direction of the input signal to the field effect transistor amplifier means and thereby inhibit saturation under conditions of large transients in radiation input or under conditions of progressive changes in radiation input of low magnitude.
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Abstract
A radiation detector circuit including a pyroelectric detector element and field effect transistor amplifier means. In order to inhibit saturation of the amplifier means under conditions of large transients in the radiation input or progressive changes in radiation input of low magnitude, at least one ultra-low leakage non-linear device is connected in the part of the circuit including the gate electrode of the amplifier means and the detector element. In one embodiment a pair of picoampere diodes are reverse parallel connected across the detector element and the circuit is formed as a hybrid microcircuit device having three external terminal connections. In another embodiment the non-linear device is incorporated in a feedback path between the output side of an amplification stage and the detector element.
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Citations
14 Claims
- 1. A circuit arrangement comprising a radiation detector element of pyroelectric material, field effect transistor amplifier means connected to the detector element to receive an input signal therefrom, said field effect transistor having a gate electrode, at least one ultra-low leakage non-linear device connected in a part of the circuit including the gate electrode of the field effect transistor amplifier means and the detector element, said non-linear device serving to limit the excursion in one direction of the input signal to the field effect transistor amplifier means and thereby inhibit saturation under conditions of large transients in radiation input or under conditions of progressive changes in radiation input of low magnitude.
- 7. A radiation detector device comprising an envelope, an element of pyroelectric material located within the envelope so as to receive the radiation to be detected, said pyroelectric element having first and second electrodes, a junction field effect transistor element situated in the envelope and having a gate electrode connected to the first electrode of the element of pyroelectric material, at least one ultra-low leakage non-linear device located within the envelope and electrically connected between said first electrode of the pyroelectric element and a terminal connection extending from the envelope, the field effect transistor having source and drain electrodes connected to first and second terminal connections extending from the envelope, and means connecting the second electrode of the element of pyroelectric material to a third terminal connection extending from the envelope.
- 13. A radiation detector device comprising a pyroelectric element having first and second electrodes, an FET amplifier having a gate electrode connected to said pyroelectric element first electrode, and asymmetrical ultra-low leakage non-linear device means connected across said pyroelectric element first and second electrodes so as to limit the signal excursion in one direction of a signal supplied by the pyroelectric element to the gate electrode of the FET amplifier in a sense to oppose saturation of said FET amplifier.
Specification