Solid-state image sensing device with image pick-up bolometers for noise containing image signal and reference bolometers for estimating noise and read-out circuit for producing noise-free image signal
AssigneeNEC Corporation
InventorTsutomu Endoh
Life of this patent
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Abstract
A solid-state infrared image sensing device has an image pick-up pixel array having respective bolometers sequentially connected to a read-out circuit for producing an image carrying signal: However, the image carrying signal contains a fixed pattern noise due to the pattern of the bolometers: In order to produce a first reference signal representative of the standard magnitude of fixed pattern noise and a second reference signal representative of a deviation from the standard magnitude to the magnitude of fixed pattern noise at a selected image pick-up pixel, reference pixels are provided around the image pick-up pixel array.
Claims17
A solid-state image sensing device comprising:
- a plurality of image pick-up pixels respectively including bolometers varying the resistivity thereof depending upon the magnitude of an electromagnetic power incident thereon, and connected to a first constant voltage source;
- a first signal output node for outputting an output data signal containing a noise component due to a pattern of said plurality of image pick-up pixels and representative of said resistivity of a selected image pick-up pixel sequentially selected from said plurality of image pick-up pixels;
- a second signal output node for outputting a reference signal representative of the magnitude of said noise component of said selected image pick-up pixel;
- a selector associated with said plurality of image pick-up pixels, and sequentially connecting said first signal output node through the bolometer of said selected image pick-up pixel to said first constant voltage source for producing said output data signal;
- and
- a plurality of reference pixels located in the vicinity of said plurality of image pick-up pixels so as to produce said reference signal.
A read-out circuit connected to a solid-state image sensing device including a plurality of image pick-up pixels each having a bolometer, comprising:
- a first bipolar transistor connected between a common node and a first constant voltage source through the bolometer of a selected image pick-up pixel sequentially selected from said plurality of image pick-up pixels, and flowing a first branch current of a main current between said common node and said first constant voltage source, said bolometer of said selected image pick-up pixel having a resistivity representative of the intensity of a part of an electro-magnetic radiation and a noise component;
- a second bipolar transistor connected between a second constant voltage source different in voltage level from said first constant voltage source and said common node through bolometers of first reference pixels incorporated in said solid-state image sensing device, and flowing said main current between said second constant voltage source and said common node, said first reference pixels having a resistivity representative of a deviation of said noise component from a standard noise component of one of said plurality of image pick-up pixels;
- a third bipolar transistor connected between said common node and said first constant voltage source through bolometers of second reference pixels incorporated in said solid-state image sensing device, and flowing a second branch current of said main current between said common node and said first constant voltage source, said second reference pixels having a resistivity representative of said standard noise component;
- an integrating capacitor connected between said first constant voltage source and said common node;
- and
- a reset circuit connected between a source of reset level and said common node for periodically resetting said integrating capacitor to said reset level.
Dependencies are inferred from the claim text.