Semiconductor Image Sensing Device
First Claim
1. A semiconductor image sensing device comprising:
- a plurality of pixel circuits divided into a plurality of pixel groups; and
an accumulated charge exhaust circuit provided corresponding to each said pixel group, whereineach of said pixel groups includes a plurality of said pixel circuits,each of said pixel circuits includes;
a first photodetection element for generating a signal charge corresponding to an incident light quantity to the pixel circuit;
a first node having predetermined capacitance and being accumulated said signal charge generated by said first photodetection element; and
a first initialization circuit for clearing said signal charge accumulated in said first node in response to switching of a frame period,said accumulated charge exhaust circuit is configured to execute a signal charge exhaust operation for exhausting said signal charge from said first node, based on an incident light quantity to the corresponding pixel group, during a charge exhaust period previously set at a predetermined timing during each said frame period,said signal charge exhaust operation is executed such that a signal charge quantity exhausted from said first node per unit time is relatively increased as the incident light quantity to said corresponding pixel group is increased, andsaid semiconductor image sensing device further comprises a readout circuit configured to output an electric signal corresponding to said signal charge quantity accumulated in said first node, at an output timing set at a predetermined timing after said charge exhaust period during each said frame period, from each of said pixel circuits.
2 Assignments
0 Petitions
Accused Products
Abstract
A signal charge corresponding to an incident light quantity is accumulated in a first node of each pixel circuit. An accumulated charge exhaust circuit includes each of first nodes of the plurality of pixel circuits belonging to the same pixel group, and a second node connected through discharge gates functioning as variable resistance elements. Second node functions as a floating drain during an ON period of a control switch, while accumulating the signal charge overflowing from each pixel circuit, in a capacitor during an OFF period of control switch provided at an intermediate timing in one frame period. When the incident light to the pixel group is intense, a resistance value of each discharge gate is lowered in response to an increase of the signal charge accumulated in capacitor, so that the signal charge accumulated in each pixel circuit can be exhausted once at the above intermediate timing.
55 Citations
10 Claims
-
1. A semiconductor image sensing device comprising:
-
a plurality of pixel circuits divided into a plurality of pixel groups; and an accumulated charge exhaust circuit provided corresponding to each said pixel group, wherein each of said pixel groups includes a plurality of said pixel circuits, each of said pixel circuits includes; a first photodetection element for generating a signal charge corresponding to an incident light quantity to the pixel circuit; a first node having predetermined capacitance and being accumulated said signal charge generated by said first photodetection element; and a first initialization circuit for clearing said signal charge accumulated in said first node in response to switching of a frame period, said accumulated charge exhaust circuit is configured to execute a signal charge exhaust operation for exhausting said signal charge from said first node, based on an incident light quantity to the corresponding pixel group, during a charge exhaust period previously set at a predetermined timing during each said frame period, said signal charge exhaust operation is executed such that a signal charge quantity exhausted from said first node per unit time is relatively increased as the incident light quantity to said corresponding pixel group is increased, and said semiconductor image sensing device further comprises a readout circuit configured to output an electric signal corresponding to said signal charge quantity accumulated in said first node, at an output timing set at a predetermined timing after said charge exhaust period during each said frame period, from each of said pixel circuits. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
Specification