Image sensing apparatus and imaging system
An image sensing apparatus includes a pixel array including a light-shielded area where light-shielded pixels are arranged, and an effective area where non-light-shielded pixels are arranged. Each of the light-shielded pixels includes a first photoelectric conversion unit, a first charge-voltage converter which converts charges generated in the first photoelectric conversion unit into a voltage, and a first amplification transistor functioning as a MOS transistor which receives, at the gate, the voltage converted by the first charge-voltage converter. Each of the non-light-shielded pixels includes a second photoelectric conversion unit, a second charge-voltage converter which converts charges generated in the second photoelectric conversion unit into a voltage, and a second amplification transistor functioning as a MOS transistor which receives, at the gate, the voltage converted by the second charge-voltage converter. The gate capacitance of the first amplification transistor is larger than that of the second amplification transistor.
1. An image sensing apparatus comprising a pixel array including a light-shielded area where light-shielded pixels are arranged, and an effective area where non-light-shielded pixels are arranged,
each of the light-shielded pixels including
a first photoelectric conversion unit,
a first charge-voltage converter which converts charges generated in the first photoelectric conversion unit into a voltage, and
a first amplification transistor functioning as a MOS transistor which receives, at a gate, the voltage converted by the first charge-voltage converter, and
each of the non-light-shielded pixels including
a second photoelectric conversion unit,
a second charge-voltage converter which converts charges generated in the second photoelectric conversion unit into a voltage, and
a second amplification transistor functioning as a MOS transistor which receives, at a gate, the voltage converted by the second charge-voltage converter,
wherein a gate capacitance of the first amplification transistor is larger than a gate capacitance of the second amplification transistor.
2. The apparatus according to claim 1 , wherein
a gate area of the first amplification transistor is larger than a gate area of the second amplification transistor.
3. The apparatus according to claim 2 , wherein
a gate length of the first amplification transistor is larger than a gate length of the second amplification transistor.
4. The apparatus according to claim 2 , wherein
a gate width of the first amplification transistor is larger than a gate width of the second amplification transistor.
5. The apparatus according to claim 1 , wherein
a gate capacitance per unit area in the first amplification transistor is larger than a gate capacitance per unit area in the second amplification transistor.
6. The apparatus according to claim 5 , wherein
a thickness of a gate insulating film of the first amplification transistor is smaller than a thickness of a gate insulating film of the second amplification transistor.
7. An image sensing apparatus comprising a pixel array including a light-shielded area where light-shielded pixels are arranged, and an effective area where non-light-shielded pixels are arranged,
each of the light-shielded pixels including
a first photoelectric conversion unit,
a first charge-voltage converter which converts charges generated in the first photoelectric conversion unit into a voltage, and
a first amplification transistor functioning as a MOS transistor which receives, at a gate, the voltage converted by the first charge-voltage converter, and
each of the non-light-shielded pixels including
a second photoelectric conversion unit,
a second charge-voltage converter which converts charges generated in the second photoelectric conversion unit into a voltage, and
a second amplification transistor functioning as a MOS transistor which receives, at a gate, the voltage converted by the second charge-voltage converter,
wherein the first amplification transistor is a buried-channel MOS transistor, and
the second amplification transistor is a surface-channel MOS transistor.
8. An imaging system comprising:
an image sensing apparatus according to claim 1 ;
an optical system which forms an image on an image sensing surface of the image sensing apparatus; and
a signal processing unit which processes a signal output from the image sensing apparatus to generate image data.