Solid-state image pickup element including a thinning method to discharge unnecessary image data

Abstract

In a case where a thinning operation is implemented at the point when signal charges are read out from each of pixels to thin out pixel information by lines (row), the thinning may be performed only in the vertical direction, but not in the horizontal direction. In an all-pixel-read-out type CCD image pickup element, a discharge controlling section is provided in each of VH transfer stage sections transferring signal charges from vertical CCDs to a horizontal CCD, and where a thinning mode is selected, among those signal charges transferred from a plurality of the vertical CCDs, those of a given set of columns are stopped and discharged at the respective discharge controlling sections, and those of the rest of columns are transferred to the horizontal CCD, and at the same time, those of a given set of lines (rows) are stopped and discharged for all columns, thereby performing the thinning operation over the pixel information in both the vertical and horizontal directions at the VH transfer stage.

1 .- 6 . (canceled) 
     
     
         7 . A driving method of a solid-state image pickup element comprising a plurality of sensor sections arranged in a matrix of rows and columns for performing photoelectric conversion, a first charge transfer section for transferring signal charges read out from said sensor sections in a vertical direction in which the rows are arranged, second charge transfer section for transferring the signal charges transferred from said first charge transfer section in a horizontal direction in which the columns are arranged, a discharge controlling section for selectively discharging signal charges from said first charge transfer section according to a thinning rate, and a timing generator for generating various control signals for driving said solid-state image pick-up element, said method comprising a step of:
 applying to a plurality of said discharge controlling sections at least two control signals combined in a repetitive manner along said horizontal direction, the ratio of said different control signals being equal within each combination and being configured according to said thinning rate of the horizontal direction.   
     
     
         8 . The driving method of a solid-state image pickup element according to  claim 7  further comprises:
 selecting the generation timing of the low-level pulse of one said control signals according to said thinning rate of the vertical direction. 
 
     
     
         9 . The driving method of a solid-state image pickup element as claimed in  claim 7 , wherein the three steps of
 1) transferring signal charges of a given row to said second charge transfer section;   2) driving said second charge transfer section to perform a transfer by one transfer stage; and   3) driving said first charge transfer section to transfer signal charges of a subsequent row to be transferred, to said second charge transfer section;   are repeated until the signal charges of two rows or more are accommodated in said second charge transfer section; and thereafter,   performing a step of driving said second charge transfer section to transfer and output all the signal charges.   
     
     
         10 . The driving method of a solid-state image pickup element according to  claim 7 , further comprising:
 selectively applying said control signals to a gate electrode formed over an embedded channel in order stop the transfer of, and instead discharge, those signal charges of a given set of columns selectively on a column-by-column basis, and signal charges of the remaining columns selectively on a row-by-row basis.   
     
     
         11 . The driving method of a solid-state image pickup element according to  claim 7 , wherein said embedded channel is provided adjacent a column in a direction in which the columns are arranged. 
     
     
         12 . A solid-state image pickup element comprising:
 a plurality of sensors arranged in a matrix of rows and columns for performing photoelectric conversion;   a first charge transfer section for transferring signal charges read out from said plurality of sensors vertically;   a second charge transfer section for transferring the signal charges transferred from said first charge transfer section horizontally; and   a discharge controlling section which transfers the signal charges from said first charge transfer section to the second charge transfer section, said discharge controlling section comprises a drain offset from a transfer channel and a discharging gate provided between said transfer channel and said drain, said discharging gate comprises a buried channel, formed in a same level as said transfer channel, and a gate electrode disposed over said buried channel.