Solid-state imaging element having image signal overflow path

Abstract

Since the great number of elements constituting a unit pixel having an amplification function would hinder reduction of pixel size, unit pixel n,m arranged in a matrix form is comprised of a photodiode, a transfer switch for transferring charges stored in the photodiode, a floating diffusion for storing charges transferred by the transfer switch, a reset switch for resetting the floating diffusion, and an amplifying transistor for outputting a signal in accordance with the potential of the floating diffusion to a vertical signal line, and by affording vertical selection pulse .phi.Vn to the drain of the reset switch to control a reset potential thereof, pixels are selected in units of rows.

1 . (canceled) 
     
     
         2 . An imaging device comprising:
 a differential circuit, and   a pixel including
 a photoelectric conversion element, 
 a charge store element, 
 a transfer transistor, 
 a reset transistor, and 
 an amplifying transistor, 
   wherein, during a first time period, the reset transistor is configured to connect a first voltage line to the charge store element,   wherein, during a second time period which is after the first time period, the amplifying transistor is configured to output a first signal as an offset level to a signal line,   wherein, during a third time period which is after the second time period, the transfer transistor is configured to transfer a charge stored in the photoelectric conversion element to the charge store element, and   wherein, during a fourth time period which is after the third time period, the amplifying transistor is configured to output a second signal as a signal level to the signal line.   wherein the differential circuit is configured to output a third signal according to a difference between the offset level and the signal level.   
     
     
         3 . The imaging device according to  claim 2 , wherein a region in which the oxide film is arranged is configured to discharge charge from the photoelectric conversion element to the second voltage line. 
     
     
         4 . The imaging device according to  claim 2 , wherein the first voltage line is configured to supply a first voltage and a second voltage. 
     
     
         5 . The imaging device according to  claim 2 , wherein a potential of the first voltage line is not fixed. 
     
     
         6 . The imaging device according to  claim 2 , wherein the amplifying transistor is directly connected to the signal line. 
     
     
         7 . The imaging device according to  claim 2 , wherein the charge store element is a floating diffusion region. 
     
     
         8 . The imaging device according to  claim 2 , wherein the reset transistor is configured to reset the charge store element. 
     
     
         9 . The imaging device according to  claim 2 , wherein the photoelectric conversion element is configured to convert incident light into a signal charge. 
     
     
         10 . The imaging device according to  claim 2 ,
 wherein the transfer transistor is configured to connect the photoelectric conversion element to the charge store element according to a transfer pulse supplied via a transfer control line,   wherein the reset transistor is configured to connect the first voltage line to the charge store element according to a reset pulse supplied via a reset control line, and   wherein the amplifying transistor is configured to connect the second voltage line to the signal line according to a potential of the charge store element.   
     
     
         11 . The imaging device according to  claim 10 ,
 wherein the signal line extends along a first direction, and   wherein the first voltage line, the second voltage line, and the reset control line extend along a second direction which is different with the first direction.   
     
     
         12 . The imaging device according to  claim 2 , further comprising a vertical scanning circuit and a horizontal scanning circuit. 
     
     
         13 . The imaging device according to  claim 12 , further comprising an output circuit configured to output image signals supplied from the pixel according to the horizontal scanning circuit. 
     
     
         14 . The imaging device according to  claim 2 , wherein the reset transistor is a depletion type transistor. 
     
     
         15 . The imaging device according to  claim 10 , wherein a negative potential is applied to the transfer control line. 
     
     
         16 . An electronic apparatus comprising the imaging device according to  claim 2 .