Device for reading out quantities of electrical charge supplied by photodiodes having a semiconductor substrate

Claim 1

A device for reading out quantities of electrical charge supplied by photodiodes (1) having a semiconductor substrate and located at the intersections of rows and columns (4,5) in a matrix array, comprising an assembly (6), storage means (8) for creating storage potential wells in the substrate (2), each said storage potential well corresponding to a respective row or column and serving to store successively, row by row or column by column, charges coming from the respective photodiodes of each row or each column, a charge-coupled device shift register (10) having a semiconductor substrate (9) as well as control means for creating potential wells and transfer potentials in said shift register's substrate to convey electrical charges inside said register up to an output end (12) of said shift register, said end being coupled to means (13) for reading out quantities of charge, and, for each storage means (8), charge transfer means (16) having a semiconductor substrate (9), said charge transfer means having control means (18) for creating, in said substrate, transfer potentials and a receiving potential well for receiving charges contained in the corresponding storage potential well, said receiving potential wells of said transfer means (16) corresponding to the different storage potential wells that are also the potential wells of said shift register (10), and means (20) for injecting bias charges into said receiving potential wells, said control means of each transfer means (16) causing the transfer of bias charges contained in the receiving potential well of said transfer means to the corresponding storage potential well, and then the transfer of said bias charges and at least a part of said stored charges into the receiving potential well, characterized in that said shift register (10) has n successive stages for each photodiode (1), n-1 of these stages forming n-1 intermediate potential wells between, on the one hand, said receiving potential well corresponding to said photodiode and its neighboring photodiode in the same row or column, and on the other, a stage common to both the shift register (10) and said transfer means (16) corresponding to said photodiode and creating the said receiving potential well, the quantity of charge contained in each storage potential well being accounted for by said shift register (10) after n transfers of stored charges and bias charges towards said shift register, and n-1 shift operations, said charge injection means injecting bias charges into all of said shift register's receiving potential wells before each transfer of charge into said receiving potential wells, the quantity of charge to be read out for each photodiode being read after n transfers of stored charge.

Claim 2

A device for reading out quantities of electrical charge supplied by photodiodes (1) having a semiconductor substrate and located at the intersections of rows and columns (4,5) in a matrix array, comprising an assembly (6), storage means (8) for creating storage potential wells in the substrate (2), each said storage potential well corresponding to a respective row or column and serving to store successively, row by row or column by column, charges coming from the respective photodiodes of each row or each column, a charge-coupled device shift register (10) having a semiconductor substrate (9) as well as control means for creating potential wells and transfer potentials in said shift register's substrate to convey electrical charges inside said register up to an output end (12) of said shift register, said end being coupled to means (13) for reading out quantities of charge, and, for each storage means (8), charge transfer means (16) having a semiconductor substrate (9), said charge transfer means having control means (18) for creating, in said substrate, transfer potentials and a receiving potential well for receiving charges contained in the corresponding storage potential well, said receiving potential wells of said transfer means (16) corresponding to the different storage potential wells that are also the potential wells of said shift register (10), and means (20) for injecting bias charges into said receiving potential wells, said control means of each transfer means (16) causing the transfer of bias charges contained in the receiving potential well of said transfer means to the corresponding storage potential well, and then the transfer of said bias charges and at least a part of said stored charges into the receiving potential well, characterized in that said shift register (10) has n successive stages for each photodiode (1), n-1 of these stages forming n-1 intermediate potential wells between, on the one hand, said receiving potential well corresponding to said photodiode and its neighboring photodiode in the same row or column, and on the other, a stage common to both the shift register (10) and said transfer means (16) corresponding to said photodiode and creating the said receiving potential well, the quantity of charge contained in each storage potential well being accounted for by said shift register (10) after n transfers of stored charges and bias charges towards said shift register, and n-1 shift operations, said charge injection means injecting bias charges into all of said shift register's receiving potential wells before each transfer of charge into said receiving potential wells, the quantity of charge to be read out for each photodiode being read after n transfers of stored charge.