Pixel drive circuit for an image pickup apparatus
This invention provides an image pickup device comprising a plurality of pixels each including a photoelectric conversion unit, a semiconductor area to which a signal from the photoelectric conversion unit is transferred, a transfer switch for transferring the signal from the photoelectric conversion unit to the semiconductor area, and a read unit for reading out the signal from the semiconductor area, and a drive circuit for outputting a first level at which the transfer switch is set in an OFF state, a second level at which the transfer switch is set in an ON state, and a third level between the first level and the second level, wherein the drive circuit controls to hold the third level for a predetermined time while the transfer switch is changing from the ON state to the OFF state.
1. An image pickup device comprising:
a plurality of pixels each including a photoelectric conversion unit, a floating diffusion region to which a signal from said photoelectric conversion unit is transferred, a transfer switch to transfer the signal from said photoelectric conversion unit to said floating diffusion region, and an amplifying transistor whose gate is connected to said floating diffusion region to read out the signal from said floating diffusion region; and
a drive circuit controlling said transfer switch, wherein the drive circuit supplies said transfer switch with a signal of a first level to set said transfer switch to be in an OFF period by maintaining the signal at the first level for the OFF period, and supplies said transfer switch with a signal of a second level to set said transfer switch to be in an ON period by maintaining the signal at the second level for the ON period. such that a fall speed of changing from the second level to the first level is slower than a rise speed of changing from the first level to the second level,
wherein, during the ON state, charge is transferred from said photoelectric conversion unit to said floating diffusion region.
2. The device according to claim 1 , wherein said photoelectric conversion unit includes an embedded photodiode.
3. The device according to claim 1 , further comprising
an analog/digital conversion circuit adapted to convert a signal from each of said plurality of pixels into a digital signal,
a signal processing circuit adapted to process the signal from said analog/digital conversion circuit, and
a recording circuit adapted to record the signal processed by said signal processing circuit.
4. An image pickup device comprising:
a plurality of pixels each including a photoelectric conversion unit, a floating diffusion region to which a signal from said photoelectric conversion unit is transferred, a transfer switch to transfer the signal from said photoelectric conversion unit to said floating diffusion region, and an amplifying transistor whose gate is connected to said floating diffusion region; and
a drive circuit controlling said transfer switch, wherein the drive circuit supplies said transfer switch with a signal of a first level to set said transfer switch to be in an OFF period by maintaining the signal at the first level for the OFF period, and supplies said transfer switch with a signal of a second level to set said transfer switch to be in an ON period by maintaining the signal at the second level for the ON period, such that a fall speed of changing from the second level to the first level is slower than 10 V/μsec.
5. The device according to claim 4 , wherein said amplification transistor amplifies and outputs the signal in said floating diffusion region.
6. The device according to claim 4 , wherein said photoelectric conversion unit includes an embedded photodiode.
7. The device according to claim 4 , further comprising
an analog/digital conversion circuit adapted to convert a signal from each of said plurality of pixels into a digital signal,
a signal processing circuit adapted to process the signal from said analog/digital conversion circuit, and
a recording circuit adapted to record the signal processed by said signal processing circuit.
8. A drive method for an image pickup device comprising a plurality of pixels each including a photoelectric conversion unit, a floating diffusion region to which a signal from said photoelectric conversion unit is transferred, a transfer switch to transfer the signal from said photoelectric conversion unit to said floating diffusion region, and an amplifying transistor whose gate is connected to said floating diffusion region to read out the signal from said floating diffusion region, the method comprising:
a step of supplying said transfer switch with a signal of a first level to set said transfer switch to be in an OFF period by maintaining the signal at the first level for the OFF period, and supplying said transfer switch with a signal of a second level to set said transfer switch to be in an ON period by maintaining the signal at the second level for the ON period, such that a fall speed of changing from the second level to the first level is slower than a rise speed of changing from the first level to the second level,
wherein, during the ON state, charge is transferred from said photoelectric conversion unit to said floating diffusion region.
9. A drive method for an image pickup device comprising a plurality of pixels each including a photoelectric conversion unit, a floating diffusion region to which a signal from said photoelectric conversion unit is transferred, a transfer switch to transfer the signal from said photoelectric conversion unit to said floating diffusion region, and an amplifying transistor whose gate is connected to said floating diffusion region, the method comprising:
a step of supplying said transfer switch with a signal of a first level to set said transfer switch to be in an OFF period by maintaining the signal at the first level for the OFF period, and supplying said transfer switch with a signal of a second level to set said transfer switch to be in an ON period by maintaining the signal at the second level for the ON period, such that a fall speed of changing from the second level to the first level is slower than 10 V/μsec.