Photodetector array
AssigneeInternational Business Machines Corporation
InventorHon-Sum Philip Wong
Life of this patent
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Abstract
A photodetector array for sensing radiant energy is described incorporating photodetectors, a respective semiconductor region for holding charge and two transistors coupled in series at each pixel, and a column load transistor. An amplifier at the load transistor may provide gain while providing dynamic range compression and a reduction in signal noise due to resetting of the voltage at the semiconductor regions. The invention overcomes the problem of CMOS manufacturing of photodetector arrays and for a simplified circuit per pixel to enable denser arrays and reduced noise.
Claims5
An apparatus for sensing radiant energy comprising:
- an array of photodetectors for generating charge in response to radiant energy and for transferring said charge to a respective semiconductor region on a semiconductor substrate,
- each photodetector having said semiconductor region coupled to the gate of a first field effect transistor, the drain of said first field effect transistor coupled to a first power supply lead, the source of said first field effect transistor coupled to the drain of a second field effect transistor, the gate of said second field effect transistor coupled to a first control signal for selecting said respective photodetector,
- the sources of a plurality of said second field effect transistors coupled together and to one side of a resistive load to provide an output, said other side of said resistive load coupled to a power supply lead.
Dependencies are inferred from the claim text.