Solid-state image sensor and camera with charge-voltage converter
An image sensor including a photoelectric converter, a charge-voltage converter, a transfer transistor to transfer a charge from the photoelectric converter to the charge-voltage converter whereby potential of the charge-voltage converter changes to a first direction, an amplifier transistor to output a signal corresponding to potential of the charge-voltage converter to a column signal line, the amplifier transistor sequentially outputting, to the column signal line, noise level and light signal level, a capacitance between a control signal line and the charge-voltage converter, and a control unit to change a potential of the control signal line so that the potential of the charge-voltage converter changes to a second direction opposite to the first direction in a period in which the charge-voltage converter is in floating and which is prior to outputting the noise level.
1. A solid-state image sensor comprising:
a photoelectric converter;
a charge-voltage converter;
a transfer transistor configured to transfer a charge generated in the photoelectric converter to the charge-voltage converter, wherein a potential of the charge-voltage converter changes to a first direction by a transferred charge;
an amplifier transistor configured to output a signal corresponding to the potential of the charge-voltage converter to a column signal line, the amplifier transistor being configured to sequentially output, to the column signal line, a noise level before the transfer transistor transfers the charge to the charge-voltage converter and a light signal level after the transfer transistor transfers the charge to the charge-voltage converter;
a capacitance between a control signal line and the charge-voltage converter; and
a control unit configured to change a potential of the control signal line so that the potential of the charge-voltage converter changes to a second direction which is opposite to the first direction in a period in which the charge-voltage converter is in a floating state and which is prior to outputting the noise level to the column signal line,
wherein the charge-voltage converter includes a semiconductor region, the capacitance includes a capacitance component between the semiconductor region and an electrode electrically connected to the control signal line,
at least a part of the charge-voltage converter is formed in a semiconductor substrate,
the electrode is arranged on an insulating layer on the semiconductor substrate,
a second semiconductor region having the same conductivity type as that of the semiconductor region is included in the semiconductor substrate, and
the electrode is arranged on the insulating layer on a region between the semiconductor region and the second semiconductor region.
2. The sensor according to claim 1 , further comprising a second photoelectric converter, a second charge-voltage converter, and a second transfer transistor configured to transfer a charge generated in the second photoelectric converter to the second charge-voltage converter,
wherein the capacitance includes a capacitance component between the charge-voltage converter and a gate of a transistor arranged to be able to form a current path between the charge-voltage converter and the second charge-voltage converter.
3. The sensor according to claim 2 , wherein the control unit changes the potential of the control signal line to change the direction of the potential of the charge-voltage converter to the second direction, thereby transiting the transistor from off to on.
4. The sensor according to claim 1 , further comprising a reset transistor configured to reset the potential of the charge-voltage converter,
wherein the control unit changes the potential of the control signal line to change the direction of the potential of the charge-voltage converter to the second direction after the potential of the charge-voltage converter is reset by turning on the reset transistor and then the charge-voltage converter is set in the floating state by turning off the reset transistor, and in the period before the noise level is output to the column signal line.
5. A camera comprising:
a solid-state image sensor defined in claim 1 ; and
a processing unit configured to process a signal output from the solid-state image sensor.
6. A solid-state image sensor comprising:
a photoelectric converter;
a charge-voltage converter;
a transfer transistor configured to transfer a charge generated in the photoelectric converter to the charge-voltage converter, wherein a potential of the charge-voltage converter changes to a first direction by a transferred charge;
an amplifier transistor configured to output a signal corresponding to the potential of the charge-voltage converter to a column signal line, the amplifier transistor being configured to sequentially output, to the column signal line, a noise level before the transfer transistor transfers the charge to the charge-voltage converter and a light signal level after the transfer transistor transfers the charge to the charge-voltage converter;
a capacitance between a control signal line and the charge-voltage converter; and
a control unit configured to change a potential of the control signal line so that the potential of the charge-voltage converter changes to a second direction which is opposite to the first direction in a period in which the charge-voltage converter is in a floating state and which is prior to outputting the noise level to the column signal line,
wherein the charge-voltage converter includes a semiconductor region, the capacitance includes a capacitance component between the semiconductor region and an electrode electrically connected to the control signal line,
at least a part of the charge-voltage converter is formed in a semiconductor substrate,
the electrode is arranged on an insulating layer on the semiconductor substrate,
a second semiconductor region having a different conductivity type from that of the semiconductor region is included in the semiconductor substrate, and
the electrode is arranged on the insulating layer on a region between the semiconductor region and the second semiconductor region.
7. A camera comprising:
a solid-state image sensor defined in claim 6 ; and
a processing unit configured to process a signal output from the solid-state image sensor.
8. The sensor according to claim 6 , further comprising a second photoelectric converter, a second charge-voltage converter, and a second transfer transistor configured to transfer a charge generated in the second photoelectric converter to the second charge-voltage converter,
wherein the capacitance includes a capacitance component between the charge-voltage converter and a gate of a transistor arranged to be able to form a current path between the charge-voltage converter and the second charge-voltage converter.
9. The sensor according to claim 8 , wherein the control unit changes the potential of the control signal line to change the direction of the potential of the charge-voltage converter to the second direction, thereby transiting the transistor from off to on.
10. The sensor according to claim 6 , further comprising a reset transistor configured to reset the potential of the charge-voltage converter,
wherein the control unit changes the potential of the control signal line to change the direction of the potential of the charge-voltage converter to the second direction after the potential of the charge-voltage converter is reset by turning on the reset transistor and then the charge-voltage converter is set in the floating state by turning off the reset transistor, and in the period before the noise level is output to the column signal line.
11. A solid-state image sensor comprising:
a photoelectric converter;
a charge-voltage converter;
a transfer transistor configured to transfer a charge generated in the photoelectric converter to the charge-voltage converter, wherein a potential of the charge-voltage converter changes to a first direction by a transferred charge;
an amplifier transistor configured to output a signal corresponding to the potential of the charge-voltage converter to a column signal line, the amplifier transistor being configured to sequentially output, to the column signal line, a noise level before the transfer transistor transfers the charge to the charge-voltage converter and a light signal level after the transfer transistor transfers the charge to the charge-voltage converter;
a capacitance between a control signal line and the charge-voltage converter; and
a control unit configured to change a potential of the control signal line so that the potential of the charge-voltage converter changes to a second direction which is opposite to the first direction in a period in which the charge-voltage converter is in a floating state and which is prior to outputting the noise level to the column signal line,
wherein the charge-voltage converter includes a semiconductor region, the capacitance includes a capacitance component between the semiconductor region and an electrode electrically connected to the control signal line,
at least a part of the charge-voltage converter is formed in a semiconductor substrate,
the electrode is arranged on an insulating layer on the semiconductor substrate,
an element isolation is included in the semiconductor substrate, and
the electrode is arranged on the insulating layer on a region between the semiconductor region and the element isolation.
12. A camera comprising:
a solid-state image sensor defined in claim 11 ; and
a processing unit configured to process a signal output from the solid-state image sensor.
13. The sensor according to claim 11 , further comprising a second photoelectric converter, a second charge-voltage converter, and a second transfer transistor configured to transfer a charge generated in the second photoelectric converter to the second charge-voltage converter,
wherein the capacitance includes a capacitance component between the charge-voltage converter and a gate of a transistor arranged to be able to form a current path between the charge-voltage converter and the second charge-voltage converter.
14. The sensor according to claim 13 , wherein the control unit changes the potential of the control signal line to change the direction of the potential of the charge-voltage converter to the second direction, thereby transiting the transistor from off to on.
15. The sensor according to claim 11 , further comprising a reset transistor configured to reset the potential of the charge-voltage converter,
wherein the control unit changes the potential of the control signal line to change the direction of the potential of the charge-voltage converter to the second direction after the potential of the charge-voltage converter is reset by turning on the reset transistor and then the charge-voltage converter is set in the floating state by turning off the reset transistor, and in the period before the noise level is output to the column signal line.
16. A solid-state image sensor comprising:
a photoelectric converter;
a charge-voltage converter;
a transfer transistor configured to transfer a charge generated in the photoelectric converter to the charge-voltage converter, wherein a potential of the charge-voltage converter changes to a first direction by a transferred charge;
an amplifier transistor configured to output a signal corresponding to the potential of the charge-voltage converter to a column signal line, the amplifier transistor being configured to sequentially output, to the column signal line, a noise level before the transfer transistor transfers the charge to the charge-voltage converter and a light signal level after the transfer transistor transfers the charge to the charge-voltage converter;
a capacitance between a control signal line and the charge-voltage converter;
a control unit configured to change a potential of the control signal line so that the potential of the charge-voltage converter changes to a second direction which is opposite to the first direction in a period in which the charge-voltage converter is in a floating state and which is prior to outputting the noise level to the column signal line; and
an additional capacitance,
wherein the capacitance includes a capacitance component between the charge-voltage converter and a gate of a transistor arranged to be able to form a current path between the additional capacitance and the charge-voltage converter.
17. The sensor according to claim 16 , wherein the control unit changes the direction of the potential of the control signal line to change the potential of the charge-voltage converter to the second direction, thereby transiting the transistor from off to on.
18. The sensor according to claim 16 , further comprising a reset transistor configured to reset the potential of the charge-voltage converter,
wherein the control unit changes the potential of the control signal line to change the direction of the potential of the charge-voltage converter to the second direction after the potential of the charge-voltage converter is reset by turning on the reset transistor and then the charge-voltage converter is set in the floating state by turning off the reset transistor, and in the period before the noise level is output to the column signal line, and
the control unit resets the additional capacitance by turning on the transistor in at least a part of a period in which the reset transistor resets the potential of the charge-voltage converter.
19. The sensor according to claim 16 , further comprising a reset transistor configured to reset the potential of the charge-voltage converter,
wherein the control unit changes the potential of the control signal line to change the direction of the potential of the charge-voltage converter to the second direction after the potential of the charge-voltage converter is reset by turning on the reset transistor and then the charge-voltage converter is set in the floating state by turning off the reset transistor, and in the period before the noise level is output to the column signal line.