Active pixel sensor having intra-pixel charge transfer with analog-to-digital converter
First Claim
1. An imaging device, comprising:
- a semiconductor substrate defining a plurality of pixel cell areas, and a signal handling area;
each said pixel cell area comprising;
a) a photogate overlying said substrate, accumulating photo-generated charge in an underlying portion of said substrate;
b) a charge transfer section, receiving the accumulated photo-generated charge from the photogate; and
c) a coupling section, formed on said substrate adjacent said charge transfer section, having a sensing node connected to said photogate through said charge transfer section, wherein said charge transfer section transfers stored charge from said photogate to said sensing node;
d) a buffer transistor, operating to buffer signal from said sensing node, and a selection transistor, having a gate, operated to select said pixel; and
e) an output node which receives signal only when said selection transistor is operated;
a focal plane array including a plurality of logic units, each unit of said focal plane array including a plurality of said pixel cells, each unit having said output nodes of all of said pixels connected together, and further comprising;
a readout controller, formed in said substrate, which controls readout of said pixel cells to read out one pixel cell from each of the plurality of units, substantially at the same time; and
a plurality of analog to digital converters, formed in said substrate, and each connected to an output node of a unit to read out information from said pixel cells from multiple said units in parallel.
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Accused Products
Abstract
An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node and an analog-to-digital converter formed in the substrate connected to the output of the readout circuit.
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Citations
12 Claims
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1. An imaging device, comprising:
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a semiconductor substrate defining a plurality of pixel cell areas, and a signal handling area;
each said pixel cell area comprising;
a) a photogate overlying said substrate, accumulating photo-generated charge in an underlying portion of said substrate;
b) a charge transfer section, receiving the accumulated photo-generated charge from the photogate; and
c) a coupling section, formed on said substrate adjacent said charge transfer section, having a sensing node connected to said photogate through said charge transfer section, wherein said charge transfer section transfers stored charge from said photogate to said sensing node;
d) a buffer transistor, operating to buffer signal from said sensing node, and a selection transistor, having a gate, operated to select said pixel; and
e) an output node which receives signal only when said selection transistor is operated;
a focal plane array including a plurality of logic units, each unit of said focal plane array including a plurality of said pixel cells, each unit having said output nodes of all of said pixels connected together, and further comprising;
a readout controller, formed in said substrate, which controls readout of said pixel cells to read out one pixel cell from each of the plurality of units, substantially at the same time; and
a plurality of analog to digital converters, formed in said substrate, and each connected to an output node of a unit to read out information from said pixel cells from multiple said units in parallel. - View Dependent Claims (2)
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3. An imaging device, comprising:
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a semiconductor substrate defining a plurality of pixel cell areas, and a signal handling area;
each said pixel cell area comprising;
a) a photogate; and
b) a coupling section formed on said substrate adjacent said photogate, having a sensing node connected to receive a signal indicative of photogenerated charge from said photogate and at least one coupling stage, operating to transfer charge from said underlying portion of said substrate to said sensing node;
d) a buffer transistor, operating to buffer signal from said sensing node, and a selection transistor, having a gate, operated to select said pixel; and
e) an output node which receives signal only when said selection transistor is operated.
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4. An imaging device comprising a focal plane array of pixel cells, each of said pixel cells including a monolithic semiconductor integrated circuit substrate, each of said pixel cells comprising:
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a) a photogate overlying a first portion of said substrate and operating to accumulate photo-generated charge in a first portion of said substrate that underlies said photogate;
b) a charge transfer section, formed in said substrate adjacent said photogate, having a sensing node adjacent said photogate and at least one charge coupling stage, operating to transfer charge from said first portion of said substrate to said sensing node;
c) an output node; and
d) a transistor which selectively connects said sensing node to said output node, and further comprising a plurality of A/D converters, connected to said output nodes of a plurality of said pixel cells, but less than all of said pixel cells, so that less than all of said pixel cells are attached to said A/D converter. - View Dependent Claims (5, 6, 7, 8, 9, 10)
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11. A method of forming and using an imaging device, comprising:
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defining a plurality of pixel areas, each said pixel area covering a specified area of a charge accumulating substrate;
configuring each of said plurality of pixel areas as a portion of said substrate, providing a photogate controlling a characteristic of each said portion of said charge accumulating substrate;
providing a sensing node which senses charge in said portion of said charge accumulating substrate;
selectively passing a value in said sensing node to an output node associating an A/D converter circuit with each of a plurality of unit groups of said output nodes of each pixel areas; and
connecting each output node within each said unit group to each other and passing only one output therefrom to said A/D converter to thereby read a plurality of said unit groups in parallel. - View Dependent Claims (12)
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Specification