Image sensor
AssigneeNEC Corporation
InventorsYoshinori Muramatsu, Susumu Kurosawa, Yasutaka Nakashiba, Tsuyoshi Nagata
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Abstract
According to an image sensor disclosed, a pixel circuit includes a photo-diode 14 for generating a photo-electric conversion voltage which corresponds to an input optical level, a transistor 11 which is activated in response to a Reset signal RST, to initialize the photo-diode 14 from a power supply VDD, a transistor 12 which, when connected between the power supply VDD and a bit line BL, amplifies a photo-electric conversion voltage and outputs it onto the bit line BL, and a transistor 13 which is activated by a word-line readout control signal WL, to interconnect the transistor 12 and the bit line BL, in which the transistor 11 is of a depletion type.
Claims11
An image sensor having a pixel circuit which comprises:
- a light-receiving element for generating a photo-electric conversion voltage which corresponds to an input optical level,
- a first transistor disposed between said power supply and said light-receiving element, which is activated in response to a Reset signal, to initialize said light-receiving element from a power supply,
- a second transistor connected between said power supply and a third transistor, which responsive to a control signal from the light-receiving element, amplifies said photo-electric conversion voltage and outputs said voltage onto third transistor source region, and
- the third transistor disposed between said second transistor and a bit line, which is activated by a word-line readout control signal, to interconnect said second transistor and said bit line,
- wherein said first transistor is a depletion-type transistor and said second transistor is an enhancement type transistor.
An image sensor having a pixel circuit which comprises:
- a light-receiving element for generating a photo-electric conversion voltage which corresponds to an input optical level,
- a first transistor disposed between said power supply and said light-receiving element, which is activated in response to a Reset signal, to initialize said light-receiving element from a power supply,
- a second transistor connected between said power supply and a third transistor, which responsive to a control signal, amplifies said photo-electric conversion voltage and outputs said voltage onto the third transistor source region,
- the third transistor disposed between said second transistor and a bit line, which is activated by a word-line readout control signal, to interconnect said second transistor and the bit line, and
- a fourth transistor disposed between said second transistor and said light-receiving element, which is activated in response to a gate signal, to interconnect said first transistor and said light-receiving element,
- wherein said first transistor which is activated in response to a Reset signal and said fourth transistor which is activated in response to a gate signal are depletion-type transistors and said second transistor is an enhancement type transistor.
Dependencies are inferred from the claim text.