Solid-state image pickup device in which charges overflowing a memory during a charge transfer period are directed to a floating diffusion and method of driving same
First Claim
1. A solid-state image pickup device comprising:
- (1) a plurality of pixels, each pixel including at least (a) a photoelectric transducer, (b) a charge holder configured to hold a charge that has been transferred from said photoelectric transducer, (c) a charge-voltage converter configured to convert the charge into a voltage, (d) a first transfer element configured to transfer the charge from said photoelectric transducer to said charge holder by setting a first potential barrier at a boundary between said photoelectric transducer and said charge holder, (e) a second transfer element configured to transfer the charge from said charge holder to said charge-voltage converter by setting a second potential barrier at a boundary between said charge holder and said charge-voltage converter, and (f) a resetter configured to reset the charge in said charge-voltage converter; and
(2) a drive controller configured to control driving of the plurality of pixels, wherein,the drive controller is configured such that during a charge transfer period between exposure periods, said drive controller (a) first effects a reset of said charge-voltage converter and said charge holder by applying a reset voltage to said charge-voltage converter while applying a first transfer voltage to the second transfer element to cause the second potential barrier to allow all charges in the charge holder to flow into the charge-voltage converter, and (b) then effects a transfer of charge from said photoelectric transducer to said charge-voltage converter by applying a second transfer voltage to the first transfer element to set the first potential barrier to a level allowing all of the charges to flow from the photoelectric transducer to the charge holder while also applying to said second transfer element a third transfer voltage which sets the second potential barrier to a level such that some, but not all, of the charges flowing into the charge holder can overflow into the charge-voltage converter, andthe drive controller is configured such that, during the charge transfer period, the drive controller applies the second transfer voltage for a period of time that is shorter in duration than a period of time in which the drive controller applies the third transfer voltage.
2 Assignments
0 Petitions
Accused Products
Abstract
A CMOS image sensor has an image array as a matrix of unit pixels each including at least a photodiode, a memory for holding a charge stored in the photodiode, a floating diffusion region for converting the charge in the memory into a voltage, a first transfer gate for transferring the charge from the photodiode to the memory, a second transfer gate for transferring the charge from the memory to the floating diffusion region, and a resetting transistor for resetting the charge in the floating diffusion region. The unit pixels are driven to set the potential of a potential barrier at a boundary between the memory and the floating diffusion region to a potential such that a charge overflowing the memory is transferred to the floating diffusion region, when the first transfer gate is turned on. The CMOS image sensor operates in a global shutter mode for capturing moving images.
-
Citations
10 Claims
-
1. A solid-state image pickup device comprising:
-
(1) a plurality of pixels, each pixel including at least (a) a photoelectric transducer, (b) a charge holder configured to hold a charge that has been transferred from said photoelectric transducer, (c) a charge-voltage converter configured to convert the charge into a voltage, (d) a first transfer element configured to transfer the charge from said photoelectric transducer to said charge holder by setting a first potential barrier at a boundary between said photoelectric transducer and said charge holder, (e) a second transfer element configured to transfer the charge from said charge holder to said charge-voltage converter by setting a second potential barrier at a boundary between said charge holder and said charge-voltage converter, and (f) a resetter configured to reset the charge in said charge-voltage converter; and (2) a drive controller configured to control driving of the plurality of pixels, wherein, the drive controller is configured such that during a charge transfer period between exposure periods, said drive controller (a) first effects a reset of said charge-voltage converter and said charge holder by applying a reset voltage to said charge-voltage converter while applying a first transfer voltage to the second transfer element to cause the second potential barrier to allow all charges in the charge holder to flow into the charge-voltage converter, and (b) then effects a transfer of charge from said photoelectric transducer to said charge-voltage converter by applying a second transfer voltage to the first transfer element to set the first potential barrier to a level allowing all of the charges to flow from the photoelectric transducer to the charge holder while also applying to said second transfer element a third transfer voltage which sets the second potential barrier to a level such that some, but not all, of the charges flowing into the charge holder can overflow into the charge-voltage converter, and the drive controller is configured such that, during the charge transfer period, the drive controller applies the second transfer voltage for a period of time that is shorter in duration than a period of time in which the drive controller applies the third transfer voltage. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A method of driving a solid-state image pickup device including (1) a plurality of pixels each including at least (a) a photoelectric transducer, (b) a charge configured to hold a charge stored in said photoelectric transducer, (c) a charge-voltage converter configured to convert the charge held by said charge holder into a voltage, (d) a first transfer element configured to transfer the charge from said photoelectric transducer to said charge holder by setting a first potential barrier at a boundary between said photoelectric transducer and said charge holder, and (e) a second transfer element configured to transfer the charge from said charge holder to said charge-voltage converter by setting a second potential barrier at a boundary between said charge holder and said charge-voltage converter, and (f) a resetter configured to reset the charge in said charge-voltage converter;
- and (2) a drive controller which controls driving of the plurality of pixels, wherein said method comprises;
the drive controller is configured such that during a charge transfer period between exposure periods, the drive controller (a) first effects a reset of said charge-voltage converter and said charge holder by applying a reset voltage to said charge-voltage converter while applying a first transfer voltage to the second transfer element to cause the second potential barrier to allow all charges in the charge holder to flow into the charge-voltage converter, and (b) then effects a transfer of charge from said photoelectric transducer to said charge-voltage converter by applying a second transfer voltage to the first transfer element to set the first potential barrier to a level allowing all of the charges to flow from the photoelectric transducer to the charge holder while also applying to said second transfer element a third transfer voltage which sets the second potential barrier to a level such that some, but not all, of the charges flowing into the charge holder can overflow into the charge-voltage converter, and the drive controller is configured such that, during the charge transfer period, the drive controller applies the second transfer voltage for a period of time that is shorter in duration than a period of time in which the drive controller applies the third transfer voltage.
- and (2) a drive controller which controls driving of the plurality of pixels, wherein said method comprises;
-
8. An electronic instrument comprising:
-
(1) a solid-state image pickup device including a plurality of pixels, each pixel including at least (a) a photoelectric transducer, (b) a charge holder configured to hold a charge that has been transferred from said photoelectric transducer, (c) a charge-voltage converter configured to convert the charge held by said charge holder into a voltage, (d) a first transfer element configured to transfer the charge from said photoelectric transducer to said charge holder by setting a first potential barrier at a boundary between said photoelectric transducer and said charge holder, (e) a second transfer element configured to transfer the charge from said charge holder to said charge voltage converter by setting a second potential barrier at a boundary between said charge holder and said charge voltage converter, and (f) a resetter configured to reset the charge in said charge voltage converter; and (2) a drive controller configured to control driving of the plurality of pixels, wherein, the drive controller is configured such that, during a charge transfer period between exposure periods, the drive controller (a) first effects a reset of said charge-voltage converter and said charge holder by applying a reset voltage to said charge-voltage converter while applying a first transfer voltage to the second transfer element to cause the second potential barrier to allow all charges in the charge holder to flow into the charge-voltage converter, and (b) then effects a transfer of charge from said photoelectric transducer to said charge voltage-converter by applying a second transfer voltage to the first transfer element to set the first potential barrier to a level allowing all of the charges to flow from the photoelectric transducer to the charge holder while also applying to said second transfer element a third transfer voltage which sets the second potential barrier to a level such that some, but not all, of the charges flowing into the charge holder can overflow into the charge-voltage converter, and the drive controller is configured such that, during the charge transfer period, the drive controller applies the second transfer voltage for a period of time that is shorter in duration than a period of time in which the drive controller applies the third transfer voltage.
-
-
9. A solid-state image pickup device comprising:
-
at least one pixel including a photoelectric transducer, a charge holder, a charge-voltage converter, a first transfer element configured to effect transfer of charge from the photoelectric transducer to the charge holder by setting a first potential barrier at a first boundary between the photoelectric transducer and the charge holder, a second transfer element configured to effect transfer of charge from the charge holder to the charge-voltage converter by setting a second potential barrier at a second boundary between the charge holder and the charge-voltage converter, and a reset element configured to reset the charge-voltage converter; and a drive controller configured to control the driving of the at least one pixel, wherein, the drive controller is configured such that, during a charge transfer period between exposure periods, the drive controller (a) first effects a reset of said charge-voltage converter and said charge holder by applying a reset voltage to said charge-voltage converter while applying a first transfer voltage to the second transfer element to cause the second potential barrier to allow all charges in the charge holder to flow into the charge-voltage converter, and (b) then effects a transfer of charge from said photoelectric transducer to said charge-voltage converter by applying a second transfer voltage to the first transfer element to set the first potential barrier to a level allowing all of the charges to flow from the photoelectric transducer to the charge holder while also applying to said second transfer element a third transfer voltage which sets the second potential barrier to a level such that some, but not all, of the charges flowing into the charge holder can overflow into the charge-voltage converter, and the drive controller is configured such that, during the charge transfer period, the drive controller applies the second transfer voltage for a period of time that is shorter in duration than a period of time in which the drive controller applies the third transfer voltage. - View Dependent Claims (10)
-
Specification