Back to results
US 7,679,666 B2Granted
Solid-state logarithmic image sensing device
AssigneeMinolta Co., Ltd.
InventorsYoshio Hagihara, Kenji Takada
Life of this patent
Estimating the term…
Abstract
In a solid-state image-sensing device, after completion of image sensing by individual pixels, in each pixel, a signal φVRB fed to a capacitor C1 connected to the gate of a first MOS transistor T1 is turned to a high level to make it easy for a negative electric charge to flow into the MOS transistor T1. This permits quick recombination of the positive electric charges accumulated at the drain and gate of the MOS transistor T1, at the gate of a MOS transistor T2, at the anode of a photodiode, and in a capacitor C2, and thereby makes quick resetting possible.
Claims23
An image-sensing apparatus comprising:
- a photoelectric conversion portion having a photosensitive element producing an electric signal in accordance with amount of incident light and a first transistor having a first electrode connected to the photosensitive element, a second electrode, and a control electrode, the photoelectric conversion portion outputting the electric signal output from the photosensitive element and converted natural-logarithmically by making the first transistor operate in a subthreshold region;
- a lead-out path by way of which the electric signal output from the photoelectric conversion portion is fed to an output signal line;
- and
- a controller that performs image sensing by feeding a first voltage to the second electrode of the first transistor so as to make the first transistor operate in the subthreshold region,
- wherein the controller, by feeding a second voltage to the second electrode of the first transistor, permits a larger current to flow through the first transistor than before feeding the second voltage thereto.
2 more elements
An image-sensing apparatus comprising:
- a plurality of pixels, the pixels each including a photoelectric conversion portion that outputs an electric signal produced in accordance with amount of incident light and converted natural-logarithmically and a lead-out path by way of which the electric signal output from the photoelectric conversion portion is fed to the output signal line, the photoelectric conversion portion comprising:
- a photosensitive element having a first electrode to which a direct-current voltage is applied and a second electrode;
- a first transistor having a first electrode and a control electrode connected to the second electrode of the photosensitive element and a second electrode, the first transistor receiving a current output from the photosensitive element;
- and
- a second transistor having a first electrode to which a direct-current voltage is applied, a second electrode from which an electric signal is output, and a control electrode connected to the first and control electrodes of the first transistor;
- and
- a controller that performs image sensing by feeding a first voltage to the second electrode of the first transistor so as to make the first transistor operate in a subthreshold region below a threshold value thereof,
- wherein the controller resets the individual pixels by, in each pixel, feeding a second voltage to the second electrode of the first transistor so as to permit a larger current to flow through the first transistor than before feeding the second voltage thereto.
5 more elements
An image-sensing apparatus comprising:
- a plurality of pixels, the pixels each including:
- a photodiode, having two electrodes, that produces an electric signal in accordance with amount of incident light;
- a first MOS transistor having a first electrode and a gate electrode connected to one electrode of the photodiode and a second electrode;
- and
- a second MOS transistor having a first electrode, a second electrode, and a gate electrode connected to the first and gate electrodes of the first MOS transistor;
- and
- a controller that makes the individual pixels perform image sensing in such a way that the electric signal output from the photodiode is converted natural-logarithmically by feeding a first voltage to the second electrode of the first MOS transistor so as to make the first MOS transistor operate in a subthreshold region below a threshold value thereof,
- wherein the controller resets the individual pixels by, in each pixel, feeding a second voltage to the second electrode of the first MOS transistor so as to permit a larger current to flow through the first MOS transistor than before feeding the second voltage thereto.
5 more elements
Dependencies are inferred from the claim text.