Method for driving solid-state image sensor

Claim 2

In a solid-state image sensor of the type comprising (a) an array of photosensors disposed over one major surface of a semiconductor substrate, (b) an array of transistor switches disposed in one-to-one correspondence relationship with said photosensors, (c) a plurality of vertical signal lines for reading out the signal charges generated at said array of photosensors, (d) a horizontal readout charge-coupled device (CCD) shift register, and (e) a plurality of transfer gates equal in number to said plurality of vertical signal lines and interconnected between the stages of said horizontal readout CCD shift register and said plurality of vertical singal lines, a driving method comprising the steps of (A) injecting the bias charges of the same amount into the stages, respectively, of said horizontal readout CCD shift register, (B) transferring the signal charges from said array of photosensors to said vertical signal lines, respectively, (C) transferring said bias charges from said horizontal readout CCD shift register through said transfer gates to said vertical signal lines, respectively, thereby adding them to said signal charges, respectively, (D) transferring the sum of said signal and bias charges into said horizontal readout CCD shift register, and (E) driving said horizontal readout CCD shift register, thereby deriving the contents of said horizontal readout CCD shift register from an output terminal.

Claim 3

A driving method as set forth in Claim 1 further comprising the step of controlling the amount of said bias charge to be injected into said horizontal readout CCD shift register in response to the output therefrom.

Claim 4

A driving method as set forth in Claim 1 further comprising the step of employing the two-phase driving system for causing the shift of the contents through said horizontal readout CCD shift register.

Claim 5

A driving method as set forth in Claim 1 further comprising the step of maintaining the gate voltage of said transfer gates higher than the gate voltage when said signal and bias charges are transferred into said horizontal readout CCD shift register when said bias charges are transferred into said vertical signal lines.

Claim 6

In a solid-state image sensor of the type comprising (a) an array of photosensors disposed upon one major surface of a semiconductor substrate, (b) an array of transistor switches disposed in one-to-one correspondence relationships with said photosensors, respectively, (c) a plurality of vertical signal lines for reading out the signal charges generated at said array of photosensors, (d) a horizontal readout charge-coupled device (CCD) shift register, and (e) a transfer gate section interconnected between the transfer stages of said horizontal readout CCD shift register and said plurality of vertical signal lines, said transfer gate section comprising a first array of gates, a second array of gates, and an array of charge storage means, a driving method comprising the steps of (A) transferring first bias charges of the equal amount into the stages, respectively, of said horizontal readout CCD shift register, , (B) transferring the signal charges generated at said array of photosensors into said plurality of vertical signal lines, respectively, (C-l) adding said signal charges on said vertical signal lines to second bias charges, respectively, which are stored in said charge storage means, respectively, and transferring said signal charges plus said second bias charges to said charge storage means, respectively, (C-2) transferring said first bias charges from said horizontal readout CCD shift register into said charge storage means, respectively, in each of which are stored said signal charge plus said second bias charge, (D) transferring into said horizontal readout CCD shift register said signal and first bias charges out of said charge storage means in which said signal and first and second bias charge have been stored, and (E) driving said horizontal readout CCD shift register, thereby deriving the contents thereof from an output terminal.

Claim 7

In a solid-state image sensor of the type comprising (a) an array of photosensors disposed upon one major surface of a semiconductor substrate, (b) an array of transistor switches disposed in one-to-one correspondence relationships with said photosensors, respectively, (c) a plurality of vertical signal lines for reading out the signal charges generated at said array of photosensors, (d) a horizontal readout charge-coupled device (CCD) shift register, and (e) a transfer gate section interconnected between the transfer stages of said horizontal readout CCD shift register and said plurality of vertical signal lines, said transfer gate section comprising a first array of gates, a second array of gates, and an array of charge storage means, a driving method comprising the steps of (A) transferring first bias charges of the equal amount into the stages, respectively, of said horizontal readout CCD shift register, , (B) transferring the signal charges generated at said array of photosensors into said plurality of vertical signal lines, respectively, (C-l) adding said signal charges on said vertical signal lines to second bias charges, respectively, which are stored in said charge storage means, respectively, and transferring said signal charges plus said second bias charges to said charge storage means, respectively, (C-2) transferring said first bias charges from said horizontal readout CCD shift register into said charge storage means, respectively, in each of which are stored said signal charge plus said second bias charge, (D) transferring into said horizontal readout CCD shift register said signal and first bias charges out of said charge storage means in which said signal and first and second bias charge have been stored, and (E) driving said horizontal readout CCD shift register, thereby deriving the contents thereof from an output terminal.