Solid state image sensor transferring charges with high efficiency and decreased power consumption, and method of driving the same
First Claim
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1. A solid state image sensor comprising:
- a photodetector array wherein photodetectors are arranged in two-dimension vertically and horizontally;
vertical charge transfer elements each connected to a line of photodetectors aligned vertically in said photodetector array;
a pixel line selection circuit which selects a horizontal line or a group of horizontal lines of photodetectors among said photodetectors in a horizontal blanking period and transfers signal charges stored in the photodetectors in the selected line or lines to the vertical charge transfer elements;
a driver means for supplying signals to said vertical charge transfer elements for driving the signal charges in said vertical charge transfer elements; and
a horizontal charge transfer element connected to said vertical charge transfer elements, the horizontal charge transfer element transferring signal charges transferred from said vertical charge transfer elements to the external in a next horizontal period subsequent to the horizontal blanking period;
wherein said driver means comprises shift registers of a plurality of stages each corresponding to a horizontal line of said photodetector array; and
each stage of said shift registers comprises;
transfer gates operated by clock signals and inverters connected to the transfer gates;
connection lines connecting an output of the shift register in a stage to an input of the shift register in a next stage; and
a circulation loop line connecting an output of the shift registers of the last stage in said shift registers to an input of the shift register of a first stage in said shift registers.
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Abstract
A solid state image sensor of charge sweep architecture comprises photodetectors in two-dimension, vertical charge transfer elements and a horizontal charge transfer element. A driver circuit for the vertical charge transfer elements mounted in the solid state image sensor comprises a circuit for setting initial states of shift registers and a circulation loop line connecting an output of the shift register at the last stage to an input of the shift register at a first stage. Thus, a lower consumption power and high efficiency charge transfer are provided in the solid state image sensor.
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Citations
20 Claims
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1. A solid state image sensor comprising:
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a photodetector array wherein photodetectors are arranged in two-dimension vertically and horizontally; vertical charge transfer elements each connected to a line of photodetectors aligned vertically in said photodetector array; a pixel line selection circuit which selects a horizontal line or a group of horizontal lines of photodetectors among said photodetectors in a horizontal blanking period and transfers signal charges stored in the photodetectors in the selected line or lines to the vertical charge transfer elements; a driver means for supplying signals to said vertical charge transfer elements for driving the signal charges in said vertical charge transfer elements; and a horizontal charge transfer element connected to said vertical charge transfer elements, the horizontal charge transfer element transferring signal charges transferred from said vertical charge transfer elements to the external in a next horizontal period subsequent to the horizontal blanking period; wherein said driver means comprises shift registers of a plurality of stages each corresponding to a horizontal line of said photodetector array; and each stage of said shift registers comprises; transfer gates operated by clock signals and inverters connected to the transfer gates;
connection lines connecting an output of the shift register in a stage to an input of the shift register in a next stage; and
a circulation loop line connecting an output of the shift registers of the last stage in said shift registers to an input of the shift register of a first stage in said shift registers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A solid state image sensor comprising;
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a photodetector array wherein photodetectors are arranged in two-dimension vertically and horizontally; vertical charge transfer elements each connected to a line of photodetectors aligned vertically in said photodetectors array; a pixel line selection circuit which selects a horizontal line or a group of horizontal lines of photodetectors among said photodetectors in a horizontal blanking period and transfers signal charges stored in the photodetectors in the selected line or lines to the vertical charge transfer elements; a driver means for supplying signals to said vertical charge transfer elements for driving the signal charges in said vertical charge transfer elements; and a horizontal charge transfer element connected to said vertical charge transfer elements, the horizontal charge transfer element transferring signal charges transferred from said vertical charge transfer elements to the external in a next horizontal period subsequent to the horizontal blanking period; wherein said driver means comprises shift registers of a plurality of stages each corresponding to a horizontal line of said photodetector array; and each stage of said shift registers comprises;
transfer gate operated by clock signal and inverters connected to the transfer gates; and
a means for generating clock signals for driving said vertical charge transfer elements, the clock signals being of a circulating clock pattern and of a number necessary to read signal charges stored in two-dimension in a horizontal period, the number being at least twice a number of the photodetectors arranged vertically. - View Dependent Claims (15, 16)
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17. A method for driving a solid state image sensor comprising:
- a photodetector array wherein photodetectors are arranged in two-dimension vertically and horizontally;
vertical charge transfer elements each connected to a line of photodetectors aligned vertically in said photodetector array;
a pixel line selection circuit which selects a horizontal line or a group of horizontal lines of photodetectors among said photodetectors in a horizontal blanking period and transfers signal charges stored in the photodetectors in the selected line or lines to the vertical charge transfer elements;
a driver means for supplying signals to said vertical charge transfer elements for driving the signal charges in said vertical charge transfer elements; and
a horizontal charge transfer element connected to said vertical charge transfer elements, the horizontal charge transfer element transferring signal charges transferred from said vertical charge transfer elements to the external in a next horizontal period subsequent to the horizontal blanking period;
wherein said driver means comprises shift registers of a plurality of stages each corresponding to a horizontal line of said photodetector array; and
each stage of said shift registers comprises;
transfer gates operated by clock signals and inverters connected to the transfer gates;
connection lines connecting an output of the shift register in a next stage; and
a circulation loop line connecting an output of the shift registers of the last stage in said shift registers to an input of the shift register of a first stage in said shift registers;
the method comprises;a first step of resetting an input stage of the shift registers of each stage in the vertical charges transfer elements by external clocks at predetermined electrical potentials; a second step of providing outputs of the shift registers to the vertical charge transfer elements for transfer signal charge along the vertical charge transfer elements; and a third step of inputting the output of the shift register of a stage to an input of the shift register at a next stage and inputting the output of the shift register of the last stage to an input of the shift register at the first stage; wherein the second and third steps are iterated. - View Dependent Claims (18, 19, 20)
- a photodetector array wherein photodetectors are arranged in two-dimension vertically and horizontally;
Specification