Patent Publication Number: US-10791293-B2

Title: Solid-state imaging device, method for driving solid-state imaging device, and electronic apparatus

Description:
RELATED PATENT APPLICATION 
     This application is based on and claims the benefit of priority from International Application No. PCT/JP2018/012723, filed on Mar. 28, 2018, which claims priority to Japanese Patent Application No. 2017-071682, filed on Mar. 31, 2017, the contents of which are hereby incorporated by reference in their entirety. 
     TECHNICAL FIELD 
     The present invention relates to a solid-state imaging device, a method for driving a solid-state imaging device, and an electronic apparatus. 
     BACKGROUND 
     Solid-state imaging device (image sensors) including photoelectric conversion elements for detecting light and generating charges are embodied as CMOS (complementary metal oxide semiconductor) image sensors, which have been in practical use. The CMOS image sensors have been widely applied as parts of various types of electronic apparatuses such as digital cameras, video cameras, surveillance cameras, medical endoscopes, personal computers (PCs), mobile phones and other portable terminals (mobile devices). 
     The CMOS image sensor includes, for each pixel, a photodiode (a photoelectric conversion element) and a floating diffusion (FD) amplifier having a floating diffusion (FD). The mainstream design of the reading operation in the CMOS image sensor is a column parallel output processing of selecting one of the rows in the pixel array and reading the pixels in the selected row simultaneously in the column output direction. 
     Here, the CMOS image sensor may sequentially scan the pixels or rows one-by-one to read the charges generated by photoelectric conversion and stored in the photo-diodes. When such sequential scan is employed, in other words, an rolling shutter is employed as the electronic shutter, it is not possible to start and end the exposure for storing the charges produced by photoelectric conversion at the same time in all of the pixels. Therefore, the sequential scan has such a problem that, when a moving object is imaged, a captured image may experience distortion. 
     To address this problem, a global shutter is employed as the electronic shutter in a case where image distortion is not acceptable, for example, for the purposes of imaging a fast moving object and sensing that requires simultaneity among the captured images. When the global shutter is employed, the exposure can be started and ended at the same timing in all of the pixels of the pixel array part. 
     In a CMOS image sensor employing a global shutter as the electronic shutter, a pixel has therein a signal retaining part for retaining, in a sample-and-hold capacitor, a signal that is read out from a photoelectric conversion reading part, for example. The CMOS image sensor employing a global shutter stores the charges from the photodiodes in the sample-and-hold capacitors of the signal retaining parts at the same time in the form of voltage signals and subsequently sequentially read the voltage signals. In this way, the simultaneity is reliably achieved among the images (see, for example, Non-patent Literature 1). The CMOS image sensor of this type is provided with a bypass switch to enable the output from the photoelectric conversion reading part to bypass the signal retaining part and be transferred to a signal line, thereby having the rolling shutter function in addition to the global shutter function. 
     The stacked CMOS image sensor disclosed in Non-patent Literature 1 has a stacked structure in which a first substrate (a pixel die) and a second substrate (an ASIC die) are connected through microbumps (connecting parts). The first substrate has photoelectric conversion reading parts for individual pixels formed therein, and the second substrate has signal retaining parts, signal lines, a vertical scanning circuit, a horizontal scanning circuit, a column reading circuit and the like for the individual pixels formed therein. 
     Non-patent Literature 2 discloses an example configuration of a column reading circuit for a CMOS image sensor ( FIG. 5 ). The column reading circuit is configured to provide the rolling shutter function and includes a column amplifier, a correlated double sampling (CDS) circuit and an analog-to-digital converter (ADC). 
     RELEVANT REFERENCES 
     List of Relevant Non-Patent Literature 
     
         
         [Non-patent Literature 1] J. Aoki, et al., “A Rolling-Shutter Distortion-Free 3D Stacked Image Sensor with −160 dB Parasitic Light Sensitivity In-Pixel Storage Node” ISSCC 2013/SESSION 27/IMAGE SENSORS/27.3. 
         [Non-patent literature 2] S. Okura, et al., “A 3.7 M-Pixel 1300-fps CMOS Image Sensor With 5.0 G-Pixel/s High-Speed Readout Circuit,” in IEEE Journal of Solid-State Circuits, vol. 50, no. 4. pp. 1016-1024, April 2015. 
       
    
     SUMMARY 
     A conventional CMOS image sensor having both a rolling shutter function and a global shutter function has the following problem. The column reading circuit is required to have separate capacitors for retaining the reset level and the signal level of the pixel output and to organize different pixel output signals for the different functions for the processing by the ADC. The area occupied by the capacitors and the power consumed to drive the capacitors pose a problem. 
     When the CMOS image sensor is in the rolling shutter mode, a read-out reset signal and a read-out luminance signal are read out in the stated order from the pixels and processed in the column reading circuit. When the CMOS image sensor is in the global shutter mode, on the other hand, the read-out luminance signal and the read-out reset signal are read out in the stated order from the pixels and processed in the column reading circuit. Therefore, at present, the rolling shutter function and the global shutter function inevitably require column reading circuits of different configurations. 
     For the above reasons, a CMOS image sensor having a rolling shutter function and another CMOS image sensor having a global shutter function have difficulties in sharing the same column reading circuit. Likewise, a CMOS image sensor having both a rolling shutter function and a global shutter function has difficulties in using a single column reading circuit and thus requires separate column reading circuits for the respective modes. This results in disadvantages such as increased circuit scale and more complicated control. 
     The read-out signals to be read out from the pixels may be single-ended, differential or other types of signals. To address this issue, it is also necessary to provide separate column reading circuits for the respective signal types, which similarly results in disadvantages such as increased circuit scale and more complicated control. 
     The objective of the present invention is to provide a solid-state imaging device, a method for driving a solid-state imaging device and an electronic apparatus that are capable of using a same reading circuit for different operational modes and read-out signals of different signal types, which can eventually realize reduced circuit scale, less complicated control and lower power consumption. 
     A first aspect of the present invention provides a solid-state imaging device including: a pixel part having a pixel arranged therein, where the pixel performs photoelectric conversion; and a reading circuit having an analog-to-digital (AD) conversion function for analog-to-digital converting a pixel signal read out from the pixel to a signal line. The pixel signal read out from the pixel is at least either one of: a first pixel signal including a read-out reset signal and a read-out luminance signal that are read out in the stated order from the pixel in a first operation; and a second pixel signal including a read-out luminance signal and a read-out reset signal that are read out in the stated order from the pixel in a second operation. The reading circuit includes: an amplifying part for amplifying the pixel signal; and an AD converting part for analog-to-digital converting, in connection with a search signal, the pixel signal amplified by the amplifying part. A first search signal for the first pixel signal and a second search signal for the second pixel signal are configurable such that search levels thereof are inverted. 
     A second aspect of the present invention provides a method for driving a solid-state imaging device. The solid-state imaging device includes: a pixel part having a pixel arranged therein, where the pixel performs photoelectric conversion; and a reading circuit having an analog-to-digital (AD) conversion function for analog-to-digital converting a pixel signal read out from the pixel to a signal line. The reading circuit includes: an amplifying part for amplifying the pixel signal; and an AD converting part for analog-to-digital converting, in connection with a search signal, the pixel signal amplified by the amplifying part. The pixel signal read out from the pixel is at least either one of: a first pixel signal including a read-out reset signal and a read-out luminance signal that are read out in the stated order from the pixel in a first operation; and a second pixel signal including a read-out luminance signal and a read-out reset signal that are read out in the stated order from the pixel in a second operation. The search signal fed to the reading circuit is configured such that a first search signal for the first pixel signal and a second search signal for the second pixel signal are configurable such that search levels thereof are inverted. 
     A third aspect of the present invention provides an electronic apparatus including: a solid-state imaging device; and an optical system for forming a subject image on the solid-state imaging device. The solid-state imaging device includes: a pixel part having a pixel arranged therein, where the pixel performs photoelectric conversion; and a reading circuit having an analog-to-digital (AD) conversion function for analog-to-digital converting a pixel signal read out from the pixel to a signal line. The pixel signal read out from the pixel is at least either one of: a first pixel signal including a read-out reset signal and a read-out luminance signal that are read out in the stated order from the pixel in a first operation; and a second pixel signal including a read-out luminance signal and a read-out reset signal that are read out in the stated order from the pixel in a second operation. The reading circuit includes: an amplifying part for amplifying the pixel signal; and an AD converting part for analog-to-digital converting, in connection with a search signal, the pixel signal amplified by the amplifying part. A first search signal for the first pixel signal and a second search signal for the second pixel signal are configurable such that search levels thereof are inverted. 
     Advantages 
     The present invention makes it possible to use a same reading circuit for different operational modes and read-out signals of different signal types, which can eventually realize reduced circuit scale, less complicated control and lower power consumption. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram showing an example configuration of a solid-state imaging device relating to a first embodiment of the present invention. 
         FIG. 2  is a circuit diagram showing, as one example, a first pixel and a second pixel of the solid-state imaging device relating to the first embodiment of the present invention. 
         FIG. 3  is used to illustrate a pixel array in a pixel part of the solid-state imaging device relating to the first embodiment of the present invention. 
         FIG. 4  is used to illustrate an example configuration of a column output reading system in a pixel part of a solid-state imaging device relating to an embodiment of the present invention. 
         FIG. 5  is a circuit diagram showing an example configuration of a column reading circuit of the solid-state imaging device relating to the first embodiment of the present invention. 
         FIG. 6  is used to illustrate a stacked structure of the solid-state imaging device relating to the first embodiment of the present invention. 
         FIG. 7  is a timing chart including parts (A) to (D) to illustrate a reading operation performed mainly by the pixel part of the solid-state imaging device relating to the first embodiment of the present invention in a rolling shutter mode. 
         FIG. 8  is a timing chart including parts (A) to (L) to illustrate a reading operation performed mainly by the column reading circuit of the solid-state imaging device relating to the first embodiment of the present invention in the rolling shutter mode. 
         FIG. 9  is a timing chart including parts (A) to (G) to illustrate a reading operation performed mainly by the pixel part of the solid-state imaging device relating to the first embodiment of the present invention in a global shutter mode. 
         FIG. 10  is a timing chart including parts (A) to (L) to illustrate a reading operation performed mainly by the column reading circuit of the solid-state imaging device relating to the first embodiment of the present invention in the global shutter mode. 
         FIG. 11  shows an example configuration of a pixel and a column reading circuit of a solid-state imaging device relating to a second embodiment of the present invention. 
         FIG. 12  is a timing chart including parts (A) to (K) to illustrate a reading operation performed mainly by a column reading circuit of the solid-state imaging device relating to the second embodiment of the present invention in a differential rolling shutter mode. 
         FIG. 13  shows an example configuration of a first pixel of a solid-state imaging device relating to a third embodiment of the present invention. 
         FIG. 14  is a timing chart including parts (A) to (F) to illustrate a reading operation performed mainly by a pixel part of the solid-state imaging device relating to the third embodiment of the present invention in a global shutter mode. 
         FIG. 15  is a timing chart including parts (A) to (L) to illustrate a reading operation performed mainly by a column reading circuit of the solid-state imaging device relating to the third embodiment of the present invention in the global shutter mode. 
         FIG. 16  is a circuit diagram showing an example configuration of a first operational amplifier of the column reading circuit relating to the third embodiment of the present invention. 
         FIG. 17  is used to illustrate an example of how to control the input range of the first operational amplifier in a differential global shutter mode. 
         FIG. 18  is a circuit diagram showing an example configuration of a column reading circuit relating to a fourth embodiment of the present invention. 
         FIG. 19  includes parts (A) and (B) and illustrates an example configuration of a search signal input part compatible with inverted binary search, which is employed in an AD conversion part relating to the fourth embodiment of the present invention. 
         FIG. 20  shows an example configuration of an electronic apparatus to which the solid-state imaging devices relating to the embodiments of the present invention can be applied. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Embodiments of the present invention will be hereinafter described with reference to the drawings. 
     First Embodiment 
       FIG. 1  is a block diagram showing an example configuration of a solid-state imaging device according to a first embodiment of the present invention. In this embodiment, the solid-state imaging device  10  is constituted by, for example, a CMOS image sensor. 
     As shown in  FIG. 1 , the solid-state imaging device  10  is constituted mainly by a pixel part  20  serving as an image capturing part, a vertical scanning circuit (a row scanning circuit)  30 , a reading circuit (a column reading circuit)  40 , a horizontal scanning circuit (a column scanning circuit)  50 , and a timing control circuit  60 . Among these components, for example, the vertical scanning circuit  30 , the reading circuit  40 , the horizontal scanning circuit  50 , and the timing control circuit  60  constitute the reading part  70  for reading out pixel signals. 
     In the first embodiment, the pixels constituting the pixel part  20  of the solid-state imaging device  10  include a first pixel that includes a photoelectric conversion reading part and a signal retaining part and a second pixel that includes a photoelectric conversion reading part, as will be described in detail below. With such configuration, the solid-state imaging device  10  is configured, for example, as a stacked CMOS image sensor capable of operating in both of a rolling shutter mode or a first operation and a global shutter mode or a second operation. In the solid-state imaging device  10  relating to the first embodiment, the pixel part  20  includes a first pixel array in which photoelectric conversion reading parts of a plurality of first pixels are arranged in a matrix pattern, a retaining part array in which the signal retaining parts of the plurality of first pixels are arranged in a matrix pattern, and a second pixel array in which the photoelectric conversion reading parts of a plurality of second pixels are arranged in a matrix pattern. In the rolling shutter mode or first operation, the read-out signals of the photoelectric conversion reading parts of the first and second pixels are directly output to first vertical signal lines without traveling through bypass paths. In the global shutter mode or second operation, the retaining signals of the signal retaining parts of the first pixels are output to second vertical signal lines. 
     The column reading circuit  40  then amplifies and AD converts the pixel read-out signals transmitted through the first or second vertical signal lines. In the solid-state imaging device  10  relating to the first embodiment, the column reading circuit  40  is configured such that the single circuit configuration can be compatible with any operational modes and read-out signals of any signal types (whether the read-out signals are single-ended, differential or the like), as will be described in detail below. 
     The following outlines the configurations and functions of the parts of the solid-state imaging device  10 . In particular, the configurations and functions of the pixel part  20  and the column reading circuit  40  and the relating reading operation will be described in detail, and the stacked structure of the pixel part  20  and the reading part  70  and other features will be also described in detail. 
     (The Configurations of the First and Second Pixels and the Pixel Part  20 ) 
       FIG. 2  is a circuit diagram showing, as one example, the first and second pixels of the solid-state imaging device  10  relating to the first embodiment of the present invention. 
     The first pixel  21  arranged in the pixel part  20  includes a photoelectric conversion reading part  211  and a signal retaining part  212 . The second pixel  22  arranged in the pixel part  20  includes a photoelectric conversion part  221 . 
     The photoelectric conversion reading part  211  of the first pixel  21  includes a photodiode (a photoelectric conversion element) and an in-pixel amplifier. More specifically, the photoelectric conversion reading part  211  includes, for example, a photodiode PD 21  serving as a photoelectric converting part. For the photodiode PD 21 , one transfer transistor TG 1 -Tr serving as a transferring element, one reset transistor RST 1 -Tr serving as a resetting element, one source follower transistor SF 1 -Tr serving as a source follower element, and one output node ND 21 , and a selection transistor SEL 1 -Tr serving as a selecting element (a selection switch) are provided. As described above, the photoelectric conversion reading part  211  of the first pixel  21  relating to the first embodiment includes four transistors (4Tr), namely, the transfer transistor TG 1 -Tr, the reset transistor RST 1 -Tr, the source follower transistor SF 1 -Tr, and the selection transistor SEL 1 -Tr. 
     The photoelectric conversion reading part  211  relating to the first embodiment is connected at an output node ND 21  thereof to the input part of the signal retaining part  212  of the first pixel  21  and through the selection transistor SEL 1 -Tr to the first vertical signal line LSGN 11 . In the rolling shutter mode, the photoelectric conversion reading part  211  outputs a first pixel signal pixout 1 , which includes a read-out reset signal (signal voltage) (VRST 1 ) and a read-out luminance signal (signal voltage) (VSIG 1 ), to the first vertical signal line LSGN 11 . In the global shutter mode, the photoelectric conversion reading part  211  outputs a second pixel signal pixout 2 , which includes a read-out luminance signal (signal voltage) (VSIG 1 ) and a read-out reset signal (signal voltage) (VRST 1 ), to the signal retaining part  212 . 
     In the first embodiment, the first vertical signal line LSGN 11  is driven by a constant current source Ibias 1  in the rolling shutter mode, and the second vertical signal line LSGN 12  is driven by the constant current source Ibias 1  in the global shutter mode. The constant current source Ibias 1  is used both in the rolling shutter mode and in the global shutter mode. As shown in  FIG. 2 , a switching part  410  switches the connection target to which the constant current source Ibias 1  is connected depending on the operational mode. In the rolling shutter mode, the first vertical signal line LSGN 11  is connected to the constant current source Ibias 1 , and the second vertical signal line LSGN 12  is connected to a reference potential VSS (for example, the ground). In the global shutter mode, on the other hand, the second vertical signal line LSGN 12  is connected to the constant current source Ibias 1 , and the first vertical signal line LSGN 11  is connected to the reference potential VSS (for example, the ground). 
     The photodiode PD 21  generates signal charges (electrons) in an amount determined by the quantity of the incident light and stores the same. Description will be hereinafter given of a case where the signal charges are electrons and each transistor is an n-type transistor. However, it is also possible that the signal charges are holes or each transistor is a p-type transistor. Further, this embodiment is also applicable to the case where a plurality of photodiodes and transfer transistors share the transistors. 
     The transfer transistor TG 1 -Tr of the photoelectric conversion reading part  211  is connected between the photodiode PD 21  and the floating diffusion FD 21  and controlled by a control signal TG applied to the gate thereof through a control line. The transfer transistor TG 1 -Tr remains selected and in the conduction state during a transfer period in which the control signal TG is high (H) level, to transfer to the floating diffusion FD 21  the charges (electrons) produced by the photoelectric conversion and then stored in the photodiode PD 21 . 
     The reset transistor RST 1 -Tr is connected between a power supply line Vdd of power supply voltage VDD and the floating diffusion FD 21  and controlled by a control signal RST applied to the gate thereof through a control line. The reset transistor RST 1 -Tr remains selected and in the conduction state during a reset period in which the control signal RST is at the H level, to reset the floating diffusion FD 21  to the potential of the power supply line Vdd of the power supply voltage VDD. 
     The source follower transistor SF 1 -Tr and the selection transistor SEL 1 -Tr are connected in series between the power supply line Vdd and the first vertical signal line LSGN 11 , which is to be driven by the constant current source Ibias 1 . The output node ND 21  is formed by the connection point between the source of the source follower transistor SF 1 -Tr and the drain of the selection transistor SEL 1 -Tr. A signal line LSGN 13  between the output node ND 21  and the input part of the signal retaining part  212  is driven by a constant current source Ibias 3 , which is, for example, arranged in the input part of the signal retaining part  212 . The source follower transistor SF 1 -Tr outputs, to the output node ND 21 , a column output generated by converting the charges in the floating diffusion FD 21  to a voltage signal determined by the quantity of the charges. The column output includes a read-out reset signal (VRST 1 ) and a read-out luminance signal (VSIG 1 ), or a read-out luminance signal (VSIG 1 ) and a read-out reset signal (VRST 1 ). 
     The gate of the source follower transistor SF 1 -Tr is connected to the floating diffusion FD  2   1 , and the selection transistor SEL 1 -Tr is controlled by a control signal SEL applied to the gate thereof through a control line. The selection transistor SEL 1 -Tr remains selected and in the conduction state during a selection period in which the control signal SEL is at the H level. In this way, the source follower transistor SF 1 -Tr outputs, to the first vertical signal line LSGN 11 , a read-out reset signal (VRST 1 ) and a read-out luminance signal (VSIG 1 ) generated by converting the charges of the floating diffusion FD 21  to a voltage signal determined by the quantity of the charges. 
     The signal retaining part  212  of the first pixel  21  basically includes an input part  2121  connected to the constant current source Ibias 3 , a sample holding part  2122 , an output part  2123 , and nodes ND 22  to ND 24 . 
     The constant current source Ibias 3  is connected between the node ND 22  and the reference potential VSS and controlled to remain on during a predetermined period of time in a global shutter period, for example. 
     In place of the constant current source Ibias 3 , a switch element may be provided, which is connected between the node ND 22  and the reference potential VSS and controlled to remain on during a predetermined period of time in a global shutter period, for example. 
     The sample holding part  2122  includes a switch element SW 21  that may selectively connects the sample-and-hold capacitors of the sample holding part  2122  to the output node ND 21  of the photoelectric conversion reading part  211  during a global shutter period or second period, sample-and-hold capacitors C 21 , C 22  that are capable of retaining the signal output from the output node ND 21  of the photoelectric conversion reading part  211  of the first pixel  21 , and a reset transistor RST 3 -Tr that may reset the node ND 24 . A terminal a of the switch element SW 21  is connected to the input node ND 22 , which is connected to the third signal line LSGN 13 , and a terminal b of the switch element SW 21  is connected to a node ND 23 , which is connected to the sample holding part  2122 . For example, while the signal sw 1  is at the high level, the terminals a and b of the switch element SW 21  are connected so that the switch element SW 21  is in the conduction state. The sample-and-hold capacitor C 21  is connected between the node ND 23  and the node ND 24 . The sample-and-hold capacitor C 22  is connected between the node ND 24  and the reference potential VSS. 
     The reset transistor RST 3 -Tr is connected between the power supply line Vdd of the power supply voltage VDD and the node ND 24  and controlled by the control signal RST 3  applied to the gate thereof through the control line. The reset transistor RST 3 -Tr remains selected and in the conduction state during a reset period in which the control signal RST 3  is at the H level and resets the node ND 24  (and the capacitors C 21 , C 22 ) to the potential of the power supply line Vdd of the power supply voltage VDD. 
     The output part  2123  includes a source follower transistor SF 3 -Tr for outputting the signals retained in the sample-and-hold capacitors C 21 , C 22  in accordance with the retained voltage in a global shutter period or second period, and selectively outputs the retained signals through the selection transistor SEL 3 -Tr to the second vertical signal line LSGN 12 , which is to be driven by the constant current source Ibias 1 . 
     The source follower transistor SF 3 -Tr and the selection transistor SEL 3 -Tr are connected in series between the power supply line Vdd and the second vertical signal line LSGN 12 , which is to be driven by the constant current source Ibias 1 . 
     The gate of the source follower transistor SF 3 -Tr is connected to the node ND 24 , and the selection transistor SEL 3 -Tr is controlled by a control signal SEL 3  applied to the gate thereof through a control line. The selection transistor SEL 3 -Tr remains selected and in the conduction state during a selection period in which the control signal SEL 3  is at the H level. In this way, the source follower transistor SF 3 -Tr outputs, to the second vertical signal line LSGN 12 , read-out voltages (VRST, VSIG) of a column output corresponding to the voltages retained in the sample-and-hold capacitors C 21 , C 22 . 
     The above describes only one example of the configuration of the signal retaining part  212 , and the signal retaining part  212  can include a circuit of any configuration as long as the signal retaining part  212  can retain, during a global shutter period or second period, the read-out luminance signal (VSIG 1 ) and the read-out reset signal (VRST 1 ) output from the above-described photoelectric conversion reading part  211 . 
     The second pixel  22  arranged in the pixel part  20  includes a photoelectric conversion reading part  221 . The photoelectric conversion reading part  221  of the second pixel  22  has the same configuration as the photoelectric conversion reading part  211  of the first pixel  21  described above. 
     In other words, the photoelectric conversion reading part  221  of the second pixel  22  includes a photodiode (photoelectric conversion element) and an in-pixel amplifier. More specifically, the photoelectric conversion reading part  221  includes, for example, a photodiode PD 22  serving as a photoelectric conversion part. For the photodiode PD 22 , the photoelectric conversion reading part  221  includes one transfer transistor TG 2 -Tr serving as a transferring element, one reset transistor RST 2 -Tr serving as a resetting element, one source follower transistor SF 2 -Tr serving as a source follower element, and one selection transistor SEL 2 -Tr serving as a selecting element (selection switch). As described above, the photoelectric conversion reading part  221  of the second pixel  22  relating to the first embodiment includes four transistors (4Tr), namely, the transfer transistor TG 2 -Tr, the reset transistor RST 2 -Tr, the source follower transistor SF 2 -Tr, and the selection transistor SEL 2 -Tr. 
     In the rolling shutter mode, the photoelectric conversion reading part  221  relating to the first embodiment outputs a read-out reset signal (signal voltage) (VRST 2 ) and a read-out luminance signal (signal voltage) (VSIG 2 ), to the first vertical signal line LSGN 11 . 
     The photodiode PD 22  generates signal charges (electrons) in an amount determined by the quantity of the incident light and stores the same. Description will be given of a case where the signal charges are electrons and each transistor is an n-type transistor. However, it is also possible that the signal charges are holes or each transistor is a p-type transistor. Further, this embodiment is also applicable to the case where a plurality of photodiodes and transfer transistors share the transistors. 
     The transfer transistor TG 2 -Tr of the photoelectric conversion reading part  221  is connected between the photodiode PD 22  and the floating diffusion FD 22  and controlled by a control signal TG applied to the gate thereof through a control line. The transfer transistor TG 2 -Tr remains selected and in the conduction state during a transfer period in which the control signal TG is at the H level, to transfer to the floating diffusion FD 22  the charges (electrons) produced by the photoelectric conversion and then stored in the photodiode PD 22 . 
     The reset transistor RST 2 -Tr is connected between the power supply line Vdd of the power supply voltage VDD and the floating diffusion FD 22  and controlled by the control signal RST applied to the gate thereof through a control line. The reset transistor RST 2 -Tr remains selected and in the conduction state during a reset period in which the control signal RST is at the H level, to reset the floating diffusion FD 22  to the potential of the power supply line Vdd of the power supply voltage VDD. 
     The source follower transistor SF 2 -Tr and the selection transistor SEL 2 -Tr are connected in series between the power supply line Vdd and the first vertical signal line LSGN 11 , which is to be driven by the constant current source Ibias 1 . 
     The gate of the source follower transistor SF 2 -Tr is connected to the floating diffusion FD  2   2 , and the selection transistor SEL 2 -Tr is controlled by the control signal SEL applied to the gate thereof through a control line. The selection transistor SEL 2 -Tr remains selected and in the conduction state during a selection period in which the control signal SEL is at the H level. In this way, the source follower transistor SF 2 -Tr outputs, to the first vertical signal line LSGN 11 , a read-out reset signal (VRST 2 ) and a read-out luminance signal (VSIG 2 ) of a column output obtained by converting the charges in the floating diffusion FD 22  into a voltage signal determined by the quantity of the charges. 
     In the pixel part  20  relating to the first embodiment, the first and second pixels  22  having the above-described configurations are arranged to form a pixel array, for example, as shown in  FIG. 3 , and a plurality of pixel arrays are combined. 
       FIG. 3  is used to illustrate the pixel arrays in the pixel part  20  of the solid-state imaging device  10  relating to the first embodiment of the present invention. 
     The pixel part  20  of the solid-state imaging device  10  relating to the first embodiment includes a first pixel array  230 , a retaining part array  240 , an upper second pixel array  250 - 1  and a lower second pixel array  250 - 2 . 
     In the first pixel array  230 , photoelectric conversion reading parts  211  of a plurality of first pixels  21  are arranged in a two-dimensional matrix of N rows and M columns. In the first pixel array  230 , the photoelectric conversion reading parts  211  of the plurality of first pixels  21  are arranged in a two-dimensional matrix of N rows and M columns, such that an image having an aspect ratio of 16:9 can be output, for example. 
     In the retaining part array  240 , signal retaining parts  212  of the plurality of first pixels  21  are arranged in a two-dimensional matrix of N rows and M columns, correspondingly to the first pixel array  230 . As in the first pixel array  230 , in the retaining part array  240 , the signal retaining parts  212  of the plurality of first pixels  21  are arranged in a two-dimensional matrix of N rows and M columns, such that an image having an aspect ratio of 16:9 can be output, for example. 
     In the upper second pixel array  250 - 1 , photoelectric conversion reading parts  221  of a plurality of second pixels  22  are arranged in a two-dimensional matrix of P (P&lt;N) rows and M columns. 
     Likewise, in the lower second pixel array  250 - 2 , photoelectric conversion reading parts  221  of the plurality of second pixels  22  are arranged in a two-dimensional matrix of P (P&lt;N) rows and M columns. 
     Referring to the example shown in  FIG. 3 , the second pixel arrays  250 - 1 ,  250 - 2  are arranged on both (upper and lower) sides of the first pixel array  230  in the extending direction of the first vertical signal line LSGN 11 . Note that the second pixel array  250  may be arranged at least one of the sides of the first pixel array  230  in the extending direction of the first vertical signal line LSGN 11 . 
     In the second pixel arrays  250 - 1 ,  250 - 2 , the photoelectric conversion reading parts  221  of the plurality of second pixels  22  are arranged in a two-dimensional matrix of P (P&lt;N) rows and M columns, such that, in the rolling shutter mode, the second pixel arrays  250 - 1 ,  250 - 2  are activated, together with the first pixel array  230 , to output an image having an aspect ratio of, for example, 1:1 as a whole. The above-mentioned aspect ratio may be any ratio, for example, 4:3. 
     Note that, in the rolling shutter mode, the first pixel array  230  may be used as the region for electronic image stabilization, and an image having an aspect ratio of 16:9 may be output. 
     Here, the photoelectric conversion reading parts  211  in the same column in the first pixel array  230  and the second pixel arrays  250 - 1 ,  250 - 2  are connected to a common first vertical signal line LSGN 11 . 
     When the solid-state imaging device  10  has a stacked structure made up by a first substrate (an upper substrate) and a second substrate (a lower substrate) as will be described below, the first pixel array  230  and the second pixel arrays  250 - 1 ,  250 - 2  are formed in the first substrate, and the retaining part array  240  is formed in the second substrate so as to face the first pixel array  230 . 
     In the rolling shutter mode or first operation, in the pixel part  20  under the control of the reading part  70 , the first pixel array  230  and the second pixel arrays  250 - 1 ,  250 - 2  are activated so that the pixels are sequentially accessed and the pixel signals are read out in a row-by-row manner. 
     In addition, in the global shutter mode or second operation, in the pixel part  20  under the control of the reading part  70 , the first pixel array  230  and the retaining part array  240  are activated so that the pixel signals are read out with the selection transistors SEL 1 -Tr, SEL 2 -Tr being in the non-selected state (the signal SEL being at the low level) in the photoelectric conversion reading parts  221  of the first pixel array  230  and the second pixel arrays  250 - 1  and  250 - 2 . 
     In the pixel part  20 , the pixel signals are read out simultaneously in parallel from the pixels in each row since, for example, the gates of the transfer transistors TG-Tr, reset transistors RST-Tr, and selection transistors SEL-Tr in each row are connected to each other. 
     Since the pixel part  20  includes the pixels arranged in (N+2P) rows and M columns, the numbers of the control lines LSEL, LRST, LTG are each (N+2P) and the numbers of the first and second vertical signal lines LSGN 11  and LSGN 12  are each M. 
     The vertical scanning circuit  30  drives the photoelectric conversion reading parts  211  and the signal retaining parts  212  of the first pixels  21  and the photoelectric conversion reading parts  221  of the second pixels  22  through row-scanning control lines in shutter and reading rows, under the control of the timing control circuit  60 . Further, the vertical scanning circuit  30  outputs, according to an address signal, row selection signals indicating the row addresses of the reading row from which signals are to be read out and the shutter row in which the charges stored in the photodiodes PD are to be reset. 
     The column reading circuit  40  includes a plurality of column signal processing circuits (not shown) arranged so as to correspond to the column outputs from the pixel part  20 , and the column reading circuit  40  may be configured such that the plurality of column signal processing circuits are capable of processing the columns in parallel. The column reading circuit  40  amplifies and AD converts, in the rolling shutter mode or first operation, first pixel signals pixout 1  (VSL 1 ) that are read out from the photoelectric conversion reading parts  211  of the first pixels  21  and the photoelectric conversion reading parts  221  of the second pixels  22  to the first vertical signal lines LSGN  11  and, in the global shutter mode or the second operation, second pixel signals pixout 2  (VSL 2 ) that are read out from the signal retaining parts  212  of the first pixels  21  to the second vertical signal lines LSGN 12 . 
     Here, the first pixel signal pixout 1  (VSL 1 ) denotes a pixel read-out signal including a read-out reset signal VRST and a read-out luminance signal VSIG that are sequentially read out from the pixel (in the present example, the photoelectric conversion reading part  211  of the first pixel  21  and the photoelectric conversion reading part  221  of the second pixel  22 ) in the rolling shutter mode or the first operation. The second pixel signal pixout 2  (VSL 2 ) denotes a pixel read-out signal including a read-out luminance signal VSIG and a read-out reset signal VRST that are sequentially read out from the pixel (in the present example, the photoelectric conversion reading part  211  and the signal retaining part  212  of the first pixel  21 ) in the global shutter mode or second operation. 
     In the solid-state imaging device  10  relating to the first embodiment, the column reading circuit  40  is configured such that the single circuit configuration can be used in any operational modes and for read-out signals of any signal types (single-ended or differential read-out signals). 
     The column reading circuit  40  includes an amplifier (AMP)  41  and an ADC  42  as shown in  FIG. 4 , for example. With reference to  FIG. 5 , the column reading circuit  40  is constituted by an amplifying part  420  for amplifying the first pixel signal pixout 1  (VSL 1 ) and the second pixel signal pixout 2  (VSL 2 ) and an AD converting part  430  including an ADC for converting, into digital signals, the analog read-out signals VSL 1 , VSL 2  of each column output of the pixel part  20  that have been amplified by the amplifying part  420 . 
     In the first embodiment, the column reading circuit  40  includes a circuit for selecting one of the signal transmitted through the first vertical signal line LSGN 11  and the signal transmitted through the second vertical signal line LSGN 12  depending on the operational mode and inputting the selected signal into the column signal processing circuit of each column. 
       FIG. 5  is a circuit diagram showing an example configuration of the column reading circuit of the solid-state imaging device relating to the first embodiment of the present invention. 
     As shown in  FIG. 5 , the column reading circuit  40  is configured such that the amplifying part  420  for amplifying the first pixel signal pixout 1  (VSL 1 ) and the second pixel signal pixout 2  (VSL 2 ) is cascade-connected to the AD converting part  430  for converting the analog pixel signal that has been amplified by the amplifying part  420 , into a digital signal in connection with a search signal (for example, Vramp). The column reading circuit  40  additionally includes, in the input stage, an input part  440  for selecting one of the pixel read-out signals pixout based on the mode signal MODx (x=1, 2, 3, 4, . . . ) and inputting the selected pixel read-out signal into the two input terminals of the operational amplifier arranged in the amplifying part  420 . 
     The amplifying part  420  includes a first operational amplifier (hereinafter, referred to as the opamp)  421 , a first sampling capacitor (input capacitor) Cs 1 , a first feedback capacitor Cf 1 , a second sampling capacitor Cs 2 , a second feedback capacitor Cf 2 , a first switch part SW 421 , a second switch part SW 422 , a first autozero switch part SW 423 , an output node ND  421 , an offset potential VOS, and a referential potential Vref. 
     The first opamp  421  includes two input terminals, namely, a first input terminal, which is an inversion input terminal (−) in the present embodiment, and a second input terminal, which is a non-inversion input terminal (+) in the present embodiment. The first opamp  421  multiplies (amplifies) the difference between the input voltage Vin 1  input into the first input terminal (−) and the input voltage Vin 2  input into the second input terminal (+) by a gain or AO to obtain an amplified output ampout. If the gain (AO) is sufficiently high, the first input terminal (−) and the second input terminal (+) are virtually grounded when a negative feedback circuit including the first switch part SW 421  or first autozero switch part SW 423  is constituted. The output terminal of the first opamp  421  is connected to the output node ND 421 . 
     The first sampling capacitor Cs 1  is connected between (i) a first output terminal TO 1  of the input part  440 , which serves as the input line end of the first or second pixel signal, and (ii) the first input terminal (−) of the first opamp  421 . 
     The second sampling capacitor Cs 2  is connected between (i) a second output terminal TO 2  of the input part  440 , which serves as the input line end of the first or second pixel signal, and (ii) the second input terminal (+) of the first opamp  421 . 
     The first output terminal TO 1  of the input part  440  feeds one of the following pixel signals (signal voltages), which is determined based on the four mode signals MOD 1  to MOD 4 . In the case of the first mode signal MOD 1 , a single-ended first pixel signal pixout 1  obtained in the rolling shutter mode is fed from the first output terminal TO 1  of the input part  440 . In the case of the second mode signal MOD 2 , a single-ended second pixel signal pixout 2  obtained in the global shutter mode is fed from the first output terminal TO 1  of the input part  440 . In the case of the third mode signal MOD 3 , a first pixel signal pixout 1   d   1 , which is one of the differential signals obtained in the differential rolling shutter mode, is fed from the first output terminal TO 1  of the input part  440 . In the case of the fourth mode signal MOD 4 , a second pixel signal pixout 2   d   1 , which is one of the differential signals obtained in the differential global shutter mode, is fed from the first output terminal TO 1  of the input part  440 . 
     The second output terminal TO 2  of the input part  440  feeds one of the following pixel signals (signal voltages), which is determined based on the four mode signals MOD 1  to MOD 4 . In the case of the first mode signal MOD 1 , no pixel signal is fed from the second output terminal TO 2  of the input part  440 . In the case of the second mode signal MOD 2 , no pixel signal is fed from the second output terminal TO 2  of the input part  440 . In the case of the third mode signal MOD 3 , a first pixel signal pixout 1   d   2 , which is the other of the differential signals obtained in the differential rolling shutter mode, is fed from the second output terminal TO 2  of the input part  440 . In the case of the fourth mode signal MOD 4 , a second pixel signal pixout 2   d   2 , which is the other of the differential signals obtained in the differential global shutter mode, is fed from the second output terminal TO 2  of the input part  440 . 
     The first feedback capacitor Cf 1  is connected at one of the electrode ends thereof to the first input terminal (−) of the first opamp  421  and at the other electrode end thereof to the first switch part SW 421 . 
     The second feedback capacitor Cf 2  is connected at one of the electrode ends thereof to the second input terminal (+) of the first opamp  421  and at the other electrode end thereof to the reference potential VSS (for example, the ground GND). 
     The first switch part SW 421  is connected at a terminal a thereof to the other electrode end of the first sampling capacitor Cf 1 , at a terminal b thereof to the output node ND 421  (the output terminal of the first opamp  421 ) and at a terminal c thereof to an offset potential VOS. In the first switch part SW 421 , the terminals a and b are connected when the control signal CKOS is at the low level (L), and the terminals a and c are connected when the control signal CKOS is at the high level (H), for example. 
     In the present embodiment, the control signal CKOS is fed at the L level when the mode signal fed to the input part  440  is one of the first mode signal MOD 1  (the single-ended rolling shutter mode), the third mode signal MOD 3  (the differential rolling shutter mode) and the fourth mode signal MOD  4  (the differential global shutter mode) and is fed as a clock when the mode signal fed to the input part  440  is the second mode signal MOD 2  (the single-ended global shutter mode). In other words, the first feedback capacitor Cf 1  is connected between the first input terminal (−) of the first opamp  421  and the output node ND 421  when the mode signal fed to the input part  440  is one of the first mode signal MOD 1  (the single-ended rolling shutter mode), the third mode signal MOD 3  (the differential rolling shutter mode) and the fourth mode signal MOD  4  (the differential global shutter mode). The first feedback capacitor Cf 1  transits between (i) the state in which the first feedback capacitor Cf 1  is connected between the first input terminal (−) of the first opamp  421  and the output node ND 421  and (ii) the state in which the first feedback capacitor Cf 1  is connected between the first input terminal (−) of the first opamp  421  and the offset potential VOS, when the mode signal fed to the input part  440  is the second mode signal MOD 2  (the single-ended global shutter mode). 
     In the first embodiment, the offset potential VOS is set to be higher than the referential potential Vref by the voltage Vfs (VOS=Vref+Vfs). 
     The second switch part SW 422  is connected at a terminal a thereof to the second input terminal (+) of the first opamp  421  and at a terminal b thereof to the referential potential Vref. When the control signal VREFSH is fed as a clock to the second switch part SW 422 , the conduction state (ON state) is maintained between the terminals a and b while the clock is at the H level and the non-conduction state (OFF state) is maintained between the terminals a and b while the clock is at the L level. The second switch part SW 422  remains in the conduction state (ON state) between the terminals a and b when the mode signal fed to the input part  440  is one of the first mode signal MOD 1  (the single-ended rolling shutter mode) and the second mode signal MOD 2  (the single-ended global shutter mode) and transits between the conduction state (ON state) and the non-conduction state (OFF state) when the mode signal fed to the input part  440  is one of the third mode signal MOD 3  (the differential rolling shutter mode) and the fourth mode signal MOD 4  (the differential global shutter mode). 
     The autozero switch part SW 423  is connected at a terminal a thereof to the first input terminal (−) of the first opamp  421  and at a terminal b thereof to the output node ND 421  (the output terminal of the first opamp  421 ). The autozero switch part SW 423  remains in the conduction state (ON state) between the terminals a and b when the control signal AZ 1  is at the H level and remains in the non-conduction state (OFF state) between the terminals a and b when the control signal AZ 1  is at the L level. The first opamp  421  is reset when the autozero switch part SW 423  is in the conduction state. 
     The AD converting part  430  includes a second opamp  431 , a search signal input part  432 , a sample holding switch part SW 431 , a third sampling capacitor Cs 3 , a second autozero switch part SW 432 , an input node ND 431  and an output node ND 432 . 
     The second opamp  431  has two input terminals, namely, a first input terminal, which is an inversion input terminal (−) in the present embodiment, and a second input terminal, which is a non-inversion input terminal (+) in the present embodiment. During AD conversion, input signal voltage Vcmp fed into the first input terminal (−) of the second opamp  431  is signal voltage obtained by combining together the voltage retained in the third sampling capacitor Cs 3 , the voltage retained in the fourth sampling capacitor Cs 4  and the search signal Vramp provided by the search signal input part  432 . 
     Here, the search signal Vramp linearly changes at a certain gradient and is a signal having a slope waveform. In the present example, the search signal Vramp is fed as a signal having a negative slope waveform in which the level is high on the left side and low on the right side, for example, a first search signal Vramp 1  shown in  FIG. 5 . As an alternative, in the present example, the search signal Vramp is fed as a signal having a positive slope waveform in which the level is low on the left side and high on the right side, for example, a second search signal Vramp 2  shown in  FIG. 5 . The first search signal Vramp 1  and the second search signal Vramp 2  are related such that their search levels, or the slope waveform levels here, are inverted. 
     In the present embodiment, the first search signal Vramp 1  is fed into the search signal input part  432  as the search signal Vramp when the mode signal fed to the input part  440  is one of the first mode signal MOD 1  (the single-ended rolling shutter mode), the third mode signal MOD 3  (the differential rolling shutter mode) and the fourth mode signal MOD  4  (the differential global shutter mode). In the present embodiment, on the other hand, the second search signal Vramp 2  is fed into the search signal input part  432  as the search signal Vramp when the mode signal fed to the input part  440  is the second mode signal MOD 2  (the single-ended global shutter mode). 
     The search signal input part  432  shown in  FIG. 5  includes a fourth sampling capacitor (input capacitor) Cs 4 . The fourth sampling capacitor Cs 4  is connected between the input node ND 431  and the feeding line of the search signal Vramp. 
     The second opamp  431  compares the input signal voltage Vcmp input into the first input terminal (−) thereof through the third sampling capacitor Cs 3  against the referential potential Vref 2  fed to the second input terminal (+) and switches the level of the comparison output signal cmpout from the L level to the H level, or from the H level to the L level if the input signal voltage Vcmp crosses the referential potential Vref 2 . The time duration until the crossing is measured by a counter, which is not shown, so that the AD conversion is performed. As described above, the second opamp  431  serves as a comparator. 
     The third sampling capacitor (input capacitor) Cs 3  is connected between the input node ND 431  and the first input terminal (−) of the second opamp  431 . 
     The sample holding switch part SW 431  is connected at a terminal a thereof to the output node ND 421  of the amplifying part  420  and at a terminal b thereof to the input node ND 431 . The sample holding switch part SW 431  remains in the conduction state (ON state) between the terminals a and b when the control signal SH is at the H level and remains in the non-conduction state (OFF state) between the terminals a and b when the control signal SH is at the L level, for example. When the sample holding switch part SW 431  remains in the conduction state, the AD converting part  430  allows the amplified output ampout from the amplifying part  420  to be input into the input node ND 431 . 
     The autozero switch part SW 432  is connected at a terminal a thereof to the first input terminal (−) of the second opamp  431  and at a terminal b thereof to the output node ND 432  (the output terminal of the second opamp  431 ), for example. The autozero switch part SW 432  remains in the conduction state (ON state) between the terminals a and b when the control signal AZ 2  is at the H level and remains in the non-conduction state (OFF state) between the terminals a and b when the control signal AZ 2  is at the L level. The second opamp  431  is reset when the autozero switch part SW 432  is in the conduction state. 
     In the column reading circuit  40  having the above-described configuration, when the single-ended first pixel signal pixout 1  (VSL 1 ) corresponding to the first mode signal MOD 1  is input into the first sampling capacitor Cs 1  of the amplifying part  420 , the first feedback capacitor Cf 1  of the amplifying part  420  is connected to the output node ND 421  (the output terminal of the first opamp  421 ) by the first switch part SW 421  and the second input terminal (+) of the first opamp  421  is connected to the referential potential Vref. In this case, the first search signal Vramp 1  having a negative slope waveform is fed to the AD converting part  430  through the search signal input part  432 . 
     Furthermore, in the column reading circuit  40 , when the single-ended second pixel signal pixout 2  (VSL 2 ) corresponding to the second mode signal MOD 2  is input into the first sampling capacitor Cs 1  of the amplifying part  420 , the first feedback capacitor Cf 1  of the amplifying part  420  is connected to the offset potential VOS or the output node ND 421  (the output terminal of the first opamp  421 ) by the first switch part SW 421  and the second input terminal (+) of the first opamp  421  is connected to the referential potential Vref. In this case, the second search signal Vramp 2  having a positive slope waveform, which can be obtained by inverting the level of the first search signal Vramp 1 , is fed to the AD converting part  430  through the search signal input part  432 . 
     Furthermore, in the column reading circuit  40 , when the differential first pixel signals pixout 1   d   1  (VSL 1  D 1 ), pixout 1   d   2  (VSL 1 D 2 ) corresponding to the third mode signal MOD 3  are input into the first sampling capacitor Cs 1  and the second sampling capacitor Cs 2  of the amplifying part  420 , the first feedback capacitor Cf 1  of the amplifying part  420  is connected to the output node ND 421  (the output terminal of the first opamp  421 ) by the first switch part SW 421 . In this case, the first search signal Vramp 1  having a negative slope waveform is fed to the AD converting part  430  through the search signal input part  432 . 
     Furthermore, in the column reading circuit  40 , when the differential second pixel signals pixout 2   d   1  (VSL 2 D 1 ), pixout 2   d   2  (VSL 2 D 2 ) corresponding to the fourth mode signal MOD 4  are input into the first sampling capacitor Cs 1  and the second sampling capacitor Cs 2  of the amplifying part  420 , the first feedback capacitor Cf 1  of the amplifying part  420  is connected to the output node ND 421  (the output terminal of the first opamp  421 ) by the first switch part SW 421 . In this case, the first search signal Vramp 1  having a negative slope waveform is fed to the AD converting part  430  through the search signal input part  432 . 
     As described above, the column reading circuit  40  of the present first embodiment is configured to be capable of processing the pixel signals corresponding to the first mode signal MOD 1 , the second mode signal MOD 2 , the third mode signal MOD 3  and the fourth mode signal MOD 4 . Note that, in the present first embodiment, the pixel part  20  is configured to generate pixel signals corresponding to the first mode signal MOD 1  and the second mode signal MOD 2 . Accordingly, the column reading circuit  40  of the first embodiment is expected to process the single-ended first pixel signal pixout 1  (VSL 1 ) obtained in the rolling shutter mode corresponding to the first mode signal MOD 1  and the single-ended second pixel signal pixout 2  (VSL 2 ) obtained in the global shutter mode corresponding to the second mode signal MOD 2 . 
     The horizontal scanning circuit  50  scans the signals processed in the plurality of column signal processing circuits, for example, ADCs of the column reading circuit  40 , transfers the signals in a horizontal direction, and outputs the signals to a signal processing circuit (not shown). 
     The timing control circuit  60  generates timing signals required for the signal processing in the pixel part  20 , the vertical scanning circuit  30 , the column reading circuit  40 , the horizontal scanning circuit  50 , and the like. 
     In the first embodiment, in the rolling shutter mode or first operation, the reading part  70  activates the first pixel array  230  and the second pixel arrays  250 - 1 ,  250 - 2  to sequentially access the pixels and reads the single-ended first pixel signals pixout 1  in a row-by-row manner. 
     In the first embodiment, in the global shutter mode or second operation, the reading part  70  activates the first pixel array  230  and the retaining part array  240  with the selection transistors SEL 1 -Tr, SEL 2 -Tr being in the non-selected state (the signal SEL being at the low level) in the photoelectric conversion reading parts  221  of the first pixel array  230  and the second pixel arrays  250 - 1 ,  250 - 2 , to read out the single-ended second pixel signals pixout 2 . 
     (The Stacked Structure of the Solid-State Imaging Device  10 ) 
     The following describes the stacked structure of the solid-state imaging device  10  relating to the first embodiment. 
       FIG. 6  is used to illustrate the stacked structure of the solid-state imaging device  10  relating to the first embodiment. 
     The solid-state imaging device  10  relating to the first embodiment has a stacked structure of a first substrate (an upper substrate)  110  and a second substrate (a lower substrate)  120 . The solid-state imaging device  10  is formed as an imaging device having a stacked structure that is obtained, for example, by bonding wafers together and subjecting the bonded wafers to dicing. In the present example, the first substrate  110  is stacked on the second substrate  120 . 
     In the first substrate  110 , the first pixel array  230  is formed and centered around the central portion of the first substrate  110 . In the first pixel array  230 , the photoelectric conversion reading parts  211  of the first pixels  21  of the pixel part  20  are arranged. On both (upper and lower) sides of the first pixel array  230  in the extending direction of the first vertical signal lines LSGN 11 , the second pixel arrays  250 - 1 ,  250 - 2  are formed. Furthermore, in the first substrate  110 , the first vertical signal lines LSGN 11  are formed. 
     As described above, in the first embodiment, the photoelectric conversion reading parts  211  of the first pixels  21  and the photoelectric conversion reading parts  221  of the second pixels  22  are arranged in a matrix pattern in the first substrate  110 . 
     In the second substrate  120 , the retaining part array  240  (region  121 ) is formed and centered around the central portion of the second substrate  120 , and the second vertical signal lines LSGN 12  are also formed. In the retaining part array  240 , the signal retaining parts  212  of the first pixels  21 , which are connected to the output nodes ND 21  of the photoelectric conversion reading parts  211  of the first pixel array  230 , are arranged in a matrix pattern. Around the retaining part array  240 , or on the upper and lower sides in the example shown in  FIG. 6 , regions  122 ,  123  are formed for the column reading circuit  40 . The column reading circuit  40  may be configured such that it can be arranged in one of the regions on the upper and lower sides of the region  121  for the retaining part array  240 . On the lateral side of the retaining part array  240 , a region  124  for the vertical scanning circuit  30  and a region  125  for the digital and output systems are formed. In the second substrate  120 , the vertical scanning circuit  30 , the horizontal scanning circuit  50  and the timing control circuit  60  may be also formed. 
     In the above-described stacked structure, the output nodes ND 21  of the photoelectric conversion reading parts  211  of the first pixel array  230  in the first substrate  110  are electrically connected to the input nodes ND 22  of the signal retaining parts  212  of the first pixels  21  in the second substrate  120  through vias (die-to-die vias), microbumps, or the like as shown in  FIG. 2 , for example. Additionally, the first vertical signal lines LSGN 11  in the first substrate  110  are electrically connected to the input part of the column reading circuit  40  in the second substrate  120  through vias (die-to-die vias), microbumps, or the like as shown in  FIG. 2 , for example. 
     (Reading Operation of the Solid-State Imaging Device  10 ) 
     The above describes the characteristic configurations and functions of the parts of the solid-state imaging device  10 . The following now describes in detail how the solid-state imaging device  10  relating to the first embodiment reads the single-ended first pixel signals in the rolling shutter mode and the single-ended second pixel signals in the global shutter mode. 
     (Reading Operation in the Rolling Shutter Mode) 
     The following describes the reading operation in the rolling shutter mode.  FIG. 7  is a timing chart including parts (A) to (D) to illustrate the reading operation performed mainly by the pixel part of the solid-state imaging device relating to the first embodiment of the present invention in the rolling shutter mode.  FIG. 8  is a timing chart including parts (A) to (L) to illustrate the reading operation performed mainly by the column reading circuit of the solid-state imaging device relating to the first embodiment of the present invention in the rolling shutter mode. 
     In  FIG. 7 , the part (A) shows the control signal SEL for the selection transistor SEL 1 -Tr of the photoelectric conversion reading part  211  of the first pixel  21  and the selection transistor SEL 2 -Tr of the photoelectric conversion reading part  221  of the second pixel  22 . In  FIG. 7 , the part (B) shows the control signal RST for the reset transistor RST 1 -Tr of the photoelectric conversion reading part  211  of the first pixel  21  and the reset transistor RST 2 -Tr of the photoelectric conversion reading part  221  of the second pixel  22 . In  FIG. 7 , the part (C) shows the control signal TG for the transfer transistor TG 1 -Tr of the photoelectric conversion reading part  211  of the first pixel  21  and the transfer transistor TG 2 -Tr of the photoelectric conversion reading part  221  of the second pixel  22 . In  FIG. 7 , the part (D) shows the control signal sw 1  for the switch element SW 21  of the signal retaining part  212  of the first pixel  21  and the control signal SEL 3  for the selection transistor SEL 3 -Tr of the signal retaining part  212  of the first pixel  21 . 
     In  FIG. 8 , the part (A) shows the equivalent circuit of the pixel and the column reading circuit, and the part (B) shows the control signal SEL for the selection transistor SEL 1 -Tr of the photoelectric conversion reading part  211  of the first pixel  21  and the selection transistor SEL 2 -Tr of the photoelectric conversion reading part  221  of the second pixel  22 . In  FIG. 8 , the part (C) shows the control signal RST for the reset transistors RST 1 -Tr, RST 2 -Tr of the photoelectric conversion reading parts  211  and  221  of the first and second pixels  21  and  22 , and the control signal TG for the transfer transistors TG 1 -Tr, TG 2 -Tr. In  FIG. 8 , the part (D) shows the single-ended first pixel signal pixout 1  in the rolling shutter mode, the part (E) shows the control signal AZ 1  for the autozero switch part SW 423 , the part (F) shows the control signal CKOS for the first switch part SW 421 , the part (G) shows the control signal SH for the sample holding switch part SW 431 , and the part (H) shows the control signal AZ 2  for the autozero switch part SW 432 . In  FIG. 8 , the part (I) shows the output signal (amplified output) ampout from the first opamp  421 , the part (J) shows the first search signal Vramp 1 , the part (K) shows the input signal (signal voltage) Vcmp for the second opamp  431 , and the part (L) shows the output signal (comparison output) cmpout from the second opamp  431 . 
     In the rolling shutter mode period, the control signal sw 1  for the switch element SW 21 , which is designed to control the driving of all of the signal retaining parts  212  of the retaining part array  240 , and the control signal SEL 3  for controlling the selection transistor SEL 3 -Tr are set to the L level, so that the switch element SW 21  and the selection transistor SEL 3 -Tr are controlled to remain in the non-conduction state. The constant current source Ibias 3  is controlled to remain in the OFF state. 
     In other words, in the rolling shutter mode period, no access is made to any of the signal retaining parts  212  in the retaining part array  240  formed in the second substrate  120 . In the rolling shutter mode period, sequential access is made to each row in the first pixel array  230  and the second pixel arrays  250 - 1 ,  250 - 2  formed in the first substrate  110 . 
     In the rolling shutter mode period, as shown in the part (A) in  FIG. 7 , in order to select a given row in the first pixel array  230  or second pixel arrays  250 - 1 ,  250 - 2 , the control signal SEL to control (drive) the photoelectric conversion reading parts  211  in the selected row of the first pixel array  230  or the photoelectric conversion reading parts  221  in the selected row of the second pixel arrays  250 - 1 ,  250 - 2  is set to the H level, so that the selection transistors SEL 2 -Tr (or SEL 1 -Tr) in the corresponding pixels are brought into the conduction state. 
     While the above selection is made, in a reset period PR, the reset transistors RST 2 -Tr (or RST 1 -Tr) remain selected and in the conduction state during a period of time in which the control line RST is at the H level, so that the floating diffusions FD are reset to the potential of the power supply line Vdd. After the reset period PR has elapsed (or after the reset transistors RST 2 -Tr or RST 1 -Tr are brought into the non-conduction state), a first reading period starts in which the pixel signals produced during the reset state are read out. The first reading period corresponds to the time duration that starts after the end of the reset period PR, includes the timing t 1 , and ends when the transfer period PT starts. 
     At the timing t 1 , the source follower transistors SF 2 -Tr (or SF 1 -Tr) in the selected row convert the charges in the floating diffusions FD 22  (or FD 21 ) into voltage signals representing the quantity of the charges, the voltage signals are immediately output to the first vertical signal line LSGN 11  as the read-out reset signals VRST of a column output and fed to the column reading circuit  40 . 
     At this point, the first reading period ends and the transfer period PT starts. In the transfer period PT, the transfer transistors TG 2 -Tr (or TG 1 -Tr) remain selected and in the conduction state during the period of time in which the control signal TG is at the high level (H), and the charges (electrons) obtained by the photoelectric conversion and stored in the photodiodes PD 22  (or PD 21 ) are transferred to the floating diffusions FD 22  (or FD 21 ). After the transfer period PT has elapsed (or after the transfer transistors TG 2 -Tr or TG 1 -Tr are brought into the non-conduction state), a second reading period starts, which includes a timing t 2  at which the pixel signals corresponding to the charges obtained by the photoelectric conversion and stored in the photodiodes PD 2  (or PD 21 ) are read out. 
     At the timing t 2  at which the second reading period starts, the source follower transistors SF 2 -Tr (or SF 1 -Tr) in the selected row convert the charges in the flowing diffusions FD 22  (or FD 21 ) into voltage signals corresponding to the quantity of the charges, which are immediately output to the first vertical signal line LSGN 11  as the read-out luminance signals VSIG of the column output and fed to the column reading circuit  40 . 
     Subsequently, the column reading circuit  40 , which constitutes part of, for example, the reading part  70 , amplifies and AD converts the read-out reset signal VRST and the read-out luminance signal VSIG of the first pixel signal pixout 1 , which are sequentially fed, and additionally calculates the difference between the signals {VRST−VSIG} and performs the CDS. 
     More specifically, in the rolling shutter mode period, the first mode signal MOD 1  is fed to the input part  440  of the column reading circuit  40 . In addition, in the rolling shutter mode period, the control signal CKOS at the L level is fed to the first switch part SW 421  of the amplifying part  420  of the column reading circuit  40 . In this way, the terminals a and b of the first switch part SW 421  are connected, so that the first feedback capacitor Cf 1  is connected between the first input terminal (−) of the first opamp  421  and the output node ND 421 . Additionally, in the rolling shutter mode period, the second switch part SW 422  of the amplifying part  420  of the column reading circuit  40  remains in the conduction state, so that the second input terminal (+) of the first opamp  421  is connected to the referential potential Vref. 
     While these states are maintained, the first pixel signal is input into the input part  440 , and the single-ended first pixel signal pixout 1  obtained in the rolling shutter mode is fed from the first output terminal TO 1  of the input part  440  to the first input terminal (−) of the first opamp  421 , which is connected to the first sampling capacitor Cs 1 . To the first input terminal (−) of the first opamp  421 , as shown in the part (D) of  FIG. 8 , the single-ended read-out reset signal VRST and read-out luminance signal VSIG, which are sequentially read out from the photoelectric conversion reading part  211  of the first pixel  21  and the photoelectric conversion reading part  221  of the second pixel  22 , are sequentially fed. 
     Subsequently, during a predetermined period of time after the read-out reset signal VRST is input (during a predetermined period of time after the first reading period for reading the pixel signals produced during the reset state starts), as shown in the parts (E), (G) and (H) in  FIG. 8 , the control signals AZ 1 , SH and AZ 2  are set to the H level. This brings the autozero switch part SW 423  of the amplifying part  420  and the sample holding switch part SW 431  and the autozero switch part SW 432  of the AD converting part  430  into the conduction state. The lengths of the durations in which the control signals AZ 1 , SH and AZ 2  remain at the H level decrease in the order of the control signals SH, AZ 2  and AZ 1 . This resets the first opamp  421  of the amplifying part  420  and the second opamp  431  of the AD converting part  430 . As a result, the output signal (amplified output) ampout of the first opamp  421  of the amplifying part  420  becomes equal in level to the referential potential Vref and is transferred to the AD converting part  430  through the sample holding switch part SW 431  and retained in the third sampling capacitor Cs 3  and the fourth sampling capacitor Cs 4 . 
     Following this, as shown in the part (J) in  FIG. 8 , the first search signal Vramp 1  having a negative slope waveform is fed to the AD converting part  430  through the search signal input part  432 . Then, as shown in the part (K) in  FIG. 8 , the signal voltage Vcmp, which is obtained by combining together the voltage retained in the fourth sampling capacitor Cs 4  and the search signal Vramp 1  provided by the search signal input part  432  is fed into the first input terminal (−) of the second opamp  431 . In the second opamp  431 , comparison is made between the input signal voltage Vcmp, which is input into the first input terminal (−) through the third sampling capacitor Cs 3 , and the referential potential Vref 2 , which is fed to the second input terminal (+), and the comparison output signal cmpout at the H level is output as shown in the part (L) in  FIG. 8  until the input signal voltage Vcmp crosses the referential potential Vref 2 . The time duration in which the H level is kept is retained in a counter, which is not shown, so that AD conversion is performed. 
     When the first reading period ends, the read-out luminance signal VSIG, which has a lower potential than the read-out reset signal VRST, is fed to the amplifying part  420 . The output signal ampout from the first opamp  421  is now the signal (Vref+G*(VRST−VSIG)) obtained by amplifying the referential potential Vref by the result of amplifying the difference between the read-out reset signal VRST and the read-out luminance signal VSIG having a lower potential by the capacitance ratio G. During a predetermined period of time after the transfer period ends, as shown in the part (G) in  FIG. 8 , the control signal SH remains at the H level, so that the sample holding switch part SW 431  of the AD converting part  430  remains in the conduction state. As a result, the output signal (amplified output) ampout from the first opamp  421  of the amplifying part  420  becomes the signal (Vref+G*(VRST−VSIG)), is transferred to the AD converting part  430  through the sample holding switch part SW 431  and is retained in the fourth sampling capacitor Cs 4 . 
     Following this, as shown in the part (J) in  FIG. 8 , the first search signal Vramp 1  having a negative slope waveform is fed to the AD converting part  430  through the search signal input part  432 . Then, as shown in the part (K) in  FIG. 8 , the signal voltage Vcmp, which is obtained by combining together the voltage retained in the fourth sampling capacitor Cs 4  and the search signal Vramp 1  provided by the search signal input part  432  is fed into the first input terminal (−) of the second opamp  431 . In the second opamp  431 , comparison is made between the input signal voltage Vcmp, which is input into the first input terminal (−) through the third sampling capacitor Cs 3 , and the referential potential Vref 2 , which is fed to the second input terminal (+), and the comparison output signal cmpout at the H level is output as shown in the part (L) in  FIG. 8  until the input signal voltage Vcmp crosses the referential potential Vref 2 . The time duration in which the H level is kept is retained in a counter, which is not shown, so that AD conversion is performed. 
     Subsequently, the column reading circuit  40 , which constitutes part of, for example, the reading part  70 , calculates the difference {VRST−VSIG} between the read-out reset signal VRST and the read-out luminance signal VSIG and performs the CDS. 
     As described above, in the rolling shutter mode period, sequential access is made to each row in the first pixel array  230  and the second pixel arrays  250 - 1 ,  250 - 2  formed in the first substrate  110 , and the above-described reading operation is sequentially performed. 
     (Reading Operation in the Global Shutter Mode) 
     The following describes the reading operation in the global shutter mode.  FIG. 9  is a timing chart including parts (A) to (G) to illustrate the reading operation performed mainly by the pixel part of the solid-state imaging device relating to the first embodiment of the present invention in the global shutter mode.  FIG. 10  is a timing chart including parts (A) to (L) to illustrate the reading operation performed mainly by the column reading circuit of the solid-state imaging device relating to the first embodiment of the present invention in the global shutter mode. 
     In  FIG. 9 , the part (A) shows the control signal SEL for the selection transistor SEL 1 -Tr of the photoelectric conversion reading part  211  of the first pixel  21  and the selection transistor SEL 2 -Tr of the photoelectric conversion reading part  221  of the second pixel  22 . In  FIG. 9 , the part (B) shows the control signal RST for the reset transistor RST 1 -Tr of the photoelectric conversion reading part  211  of the first pixel  21  and the reset transistor RST 2 -Tr of the photoelectric conversion reading part  221  of the second pixel  22 . In  FIG. 9 , the part (C) shows the control signal TG for the transfer transistor TG 1 -Tr of the photoelectric conversion reading part  211  of the first pixel  21  and the transfer transistor TG 2 -Tr of the photoelectric conversion reading part  221  of the second pixel  22 . In  FIG. 9 , the part (D) shows the control signal sw 1  for the switch element SW 21  of the signal retaining part  212  of the first pixel  21 . In  FIG. 9 , the part (E) shows the control signal RST 3  for the reset transistor RST 3 -Tr of the signal retaining part  212  of the first pixel  21 . In  FIG. 9 , the part (F) shows the control signal SEL 3  for the selection transistor SEL 3 -Tr of the signal retaining part  212  of the first pixel  21 . In  FIG. 9 , the part (G) shows the state of the constant current source Ibias 3  (ON or OFF) arranged in the signal retaining part  212  of the first pixel  21 . 
     In  FIG. 10 , the part (A) shows the equivalent circuit of the pixel and the column reading circuit, and the part (B) shows the control signal SEL 3  for the selection transistor SEL 3 -Tr of the signal retaining part  212  of the first pixel  21 . In  FIG. 10 , the part (C) shows the control signal RST 3  for the reset transistor RST 3 -Tr of the signal retaining part  212  of the first pixel  21 . In  FIG. 10 , the part (D) shows the single-ended second pixel signal pixout 2  in the global shutter mode, the part (E) shows the control signal AZ 1  for the autozero switch part SW 423 , the part (F) shows the control signal CKOS for the first switch part SW 421 , the part (G) shows the control signal SH for the sample holding switch part SW 431 , and the part (H) shows the control signal AZ 2  for the autozero switch part SW 432 . In  FIG. 10 , the part (I) shows the output signal (amplified output) ampout from the first opamp  421 , the part (J) shows the second search signal Vramp 2 , the part (K) shows the input signal voltage Vcmp for the second opamp  421 , and the part (L) shows the output signal (comparison output) cmpout from the second opamp  431 . 
     In the global shutter mode, as shown in the part (A) of  FIG. 9 , the control signal SEL for the selection transistor SEL 1 -Tr of the photoelectric conversion reading part  211  of the first pixel  21  and the selection transistor SEL 2 -Tr of the photoelectric conversion reading part  221  of the second pixel  22  remains at the low level (L) during the entire duration of the global shutter mode period. This suspends (stops) the voltage signals from being output from the first pixel array  230  and the second pixel arrays  250 - 1 ,  250 - 2  to the first vertical signal line LSGN 11  during the entire global shutter period. Accordingly, the second pixel arrays  250 - 1 ,  250 - 2  are controlled to remain in the non-activated state. On the other hand, the first pixel array  230  is in the activated state, so that the voltage signal can be output from the output node ND 21  to the signal retaining part  212 . 
     Referring to the parts (A) to (G) in  FIG. 9 , in the period of time starting at t 11  and ending at t 12 , the photodiodes PD 21  and the floating diffusions FD 21  in all of the photoelectric conversion reading parts  211  in the first pixel array  230  are reset and charges are stored. 
     In this reset and charge storage period, as shown in the parts (D) to (G) in  FIG. 9 , the control signal sw 1  for the switch element SW 21 , which is designed to control the driving of all of the signal retaining parts  212  of the retaining part array  240 , the control signal RST 3  for controlling the reset transistor RST 3 -Tr, and the control signal SEL 3  for controlling the selection transistor SEL 3 -Tr remain at the L level, so that the switch element SW 21 , the reset transistor RST 3 -Tr and the selection transistor SEL 3 -Tr are controlled to remain in the non-conduction state and the constant current source Ibias 3  is controlled to remain in the off state. 
     While these states are maintained, in the reset period, the reset transistor RST 1 -Tr remains selected and in the conduction state during a period in which the control signal RST is at the H level. While the control signal RST remains at the H level, the transfer transistor TG 1 -Tr remains selected and in the conduction state during the period in which the control signal TG is at the H level, so that the node at which the charges (electrons) obtained by the photoelectric conversion in the photodiode PD 21  are stored is in the conduction state with the floating diffusion FD 21 . This resets the photodiode PD 21  and the floating diffusion FD 21  to the potential of the power supply line Vdd. 
     After the photodiode PD 21  is reset, the control signal TG for the transfer transistor TG 1 -Tr is switched to the L level, so that the transfer transistor TG 1 -Tr is brought into the non-conduction state, and the charges obtained by the photoelectric conversion start to be stored in the photodiode PD 21 . At this point, the control signal RST for the reset transistor RST 1 -Tr is kept at the H level, and the floating diffusion FD 21  is kept being reset to the potential of the power supply line Vdd. Subsequently, to end the reset period, before the timing t 12 , the control signal RST for the reset transistor RST 1 -Tr is switched to the L level, so that the reset transistor RST 1 -Tr is brought into the non-conduction state. After the reset period PR has elapsed (or after the reset transistor RST 1 -Tr is brought into the non-conduction state), a first reading period starts in which the pixel signals obtained during the reset state are read out. The first reading period includes the timing t 12 , and ends when the transfer period PT starts. 
     Likewise, in the signal retaining part  212 , during a predetermined period of time including the timing t 12 , the control signal RST 3  for controlling the reset transistor RST 3 -Tr is switched to and remains at the H level, the reset transistor RST 3 -Tr remains in the conduction state, and the node ND 24  is reset to the potential of the power supply line Vdd of the power supply voltage VDD. During a predetermined period of time including the timings t 12 , t 13  and t 14 , the control signal sw 1  for the switch element SW 21  is kept at the H level, so that the switch element SW 21  remains in the on state (the conduction state). Likewise, during the predetermined period of time including the timings t 12 , t 13  and t 14 , the constant current source Ibias 3  is controlled to remain in the on state. The constant current source Ibias 3  is turned off after the timing t 14  is passed and the control signal sw 1  for the switch element SW 21  is switched to the L level so that the switch element SW 21  is brought into the off state (the non-conduction state). 
     During a predetermined period of time including the timing t 12 , the source follower transistors SF 1 -Tr in all of the pixels convert the charges in the floating diffusions FD 21  into voltage signals representing the quantity of the charges, and the voltage signals are transferred to the signal retaining parts  212  through the third signal line LSGN 13  as the read-out reset signals VRST 0  of the pixels and, through the switch elements SW 21 , retained in the sample-and-hold capacitors C 21 . 
     At this point, the first reading period ends, and a predetermined period of time including the timing t 13  or a transfer period PT starts. During the transfer period PT, the transfer transistor TG 1 -Tr remains selected and in the conduction state in the period in which the control signal TG is at the high (H) level, so that the charges (electrons) produced by the photoelectric conversion and then stored in the photodiode PD 21  are transferred to the floating diffusion FD 21 . After the transfer period PT has elapsed (or after the transfer transistor TG 1 -Tr is brought into the non-conduction state), a second reading period starts, which includes a timing  14  at which the pixel signals corresponding to the charges obtained by the photoelectric conversion and stored in the photodiodes PD 2  are read out. 
     At the timing t 14  at which the second reading period starts, the source follower transistors SF 1 -Tr in all of the pixels convert the charges in the floating diffusions FD 21  into voltage signals representing the quantity of the charges, the voltage signals are transferred to the signal retaining parts  212  through the third signal line LSGN 13  as the read-out luminance signals VSIG 0  of the pixels, and the retaining signals VSIG (=VSIG 0 −VRST 0 ) are retained in the sample-and-hold capacitors C 21  and C 22  through the switch elements SW 21 . This CDS operation can cancel the offset voltage of the source follower transistors SF 1 -Tr. 
     In order to read out the retaining signals VSIG that have been retained in the above manner, a given one of the rows in the retaining part array  240  is selected. To make such a selection, the control signal SEL 3  for the selection transistors SEL 3 -Tr in the selected row is set to the H level, so that these selection transistors SEL 3 -Tr are in the conduction state. At the timing t 15 , the retaining signals VSIG (VSIG−VRST), which are retained in the sample-and-hold capacitors C 21  and C 22 , are read out. To do so, in each signal retaining part  212 , the source follower transistor SF 3 -Tr whose gate is connected to the node ND 24  outputs, to the second vertical signal line LSGN 12 , the read-out luminance signal (VSIG−VRST) of a column out corresponding to the retained voltages in the sample-and-hold capacitors C 21 , C 22  connected to the node ND 24 . The read-out luminance signal (VSIG−VRST) is fed to the column reading circuit  40 . 
     Subsequently, during a predetermined period of time including a timing t 16 , the control signal RST 3  is switched to the H level, the reset transistor RST 3 -Tr is brought into the conduction state, and the node ND 24  is reset. In the predetermined period of time including the timing t 16 , the reset retaining signals (VRST), which are retained in the sample-and-hold capacitors C 21  and C 22  connected to the node ND 24 , are read out. To do so, in each signal retaining part  212 , the source follower transistor SF 3 -Tr whose gate is connected to the node ND 24  outputs, to the second vertical signal line LSGN 12 , the read-out reset signal (VRST) of a column out corresponding to the retained voltages in the sample-and-hold capacitors C 21 , C 22  connected to the node ND 24 . The read-out reset signal (VRST) is fed to the column reading circuit  40 . 
     Subsequently, in the column reading circuit  40 , which constitutes part of, for example, the reading part  70 , the read-out luminance signal (VSIG−VRST) read out in the predetermined period of time including the timing t 15  and the read-out reset signal VRST read out in the predetermined period of time including the timing t 16  are sequentially fed to the amplifying part  420  as the second pixel signal pixout 2 . 
     For example, the column reading circuit  40 , which constitutes part of the reading part  70 , amplifies and AD converts the read-out luminance signal VSIG (CMS) and the read-out reset signal VRST of the second pixel signal pixout 2 , which are sequentially fed through the input part  440 . In addition, the column reading circuit  40  calculates the difference between the signals {VSIG−VRST} and performs the CDS to cancel the offset voltage of the source follower transistors SF 3 -Tr. 
     More specifically, in the single-ended global shutter mode period, the second mode signal MOD 2  is fed to the input part  440  of the column reading circuit  40 . Additionally, in the single-ended global shutter mode period, the second switch part SW 422  of the amplifying part  420  of the column reading circuit  40  remains in the conduction state, so that the second input terminal (+) of the first opamp  421  is connected to the referential potential Vref. 
     While these states are maintained, the second pixel signal is input into the input part  440 , and the single-ended second pixel signal pixout 2  obtained in the global shutter mode is fed from the first output terminal TO 1  of the input part  440  to the first input terminal (−) of the first opamp  421 , which is connected to the first sampling capacitor Cs 1 . To the first input terminal (−) of the first opamp  421 , as shown in the part (D) of  FIG. 10 , the single-ended read-out luminance signal VSIG and read-out reset signal VRST, which are read out from the photoelectric conversion reading part  211  of the first pixel  21  and also from the signal retaining part  212  in the stated order, are fed in the stated order. 
     Subsequently, during a predetermined period of time after the read-out luminance signal VSIG is input, the control signal AZ 1  remains at the H level, as shown in the part (E) in  FIG. 10 . This keeps the autozero switch parts SW 423  of the amplifying part  420  in the conduction state. This resets the first opamp  421  of the amplifying part  420 . As a result, the output signal (amplified output) ampout from the first opamp  421  of the amplifying part  420  becomes equal to the referential potential Vref. 
     After this, in the single-ended global shutter mode period, the control signal CKOS for the first switch part SW 421  of the amplifying part  420  of the column reading circuit  40  transits from the L level to the H level. In this way, connection is made between the terminal a and the terminal c, in place of between the terminal a and the terminal b, in the first switch part SW 421 , and the first feedback capacitor Cf 1  is connected to the output of the first opamp  421 , in place of the offset potential VOS. As a result, the output signal (amplified output) ampout from the first opamp  421  of the amplifying part  420  is shifted by the offset vfs relative to the referential potential Vref, in other words, offset-shifted to the offset potential VOS. This offset-shifting can contribute to maintaining the output range of the first opamp  421  at the same level as in the above-described rolling shutter mode. 
     During a predetermined period of time after the control signal CKOS is switched to the H level, the control signals SH and AZ 2  remain at the H level as shown in the parts (G) and (H) in  FIG. 10 . In this way, the sample holding switch part SW 431  and the autozero switch part SW 432  of the AD converting part  430  remain in the conduction state. The lengths of the durations in which the control signals SH and AZ 2  remain at the H level decrease in the order of the control signals SH and AZ 2 . This resets the second opamp  431  of the AD converting part  430 . As for the output signal (amplified output) ampout of the first opamp  421  of the amplifying part  420 , the component corresponding to the read-out luminance signal VSIG becomes equal in level to the offset potential VOS, is transferred to the AD converting part  430  through the sample holding switch part SW 431  and retained in the third sampling capacitor Cs 3  and the fourth sampling capacitor Cs 4 . 
     Following this, as shown in the part (J) in  FIG. 10 , the second search signal Vramp 2  having a positive slope waveform, which can be obtained by inverting the level of the first search signal Vramp 1  having a negative slope waveform, is fed to the AD converting part  430  through the search signal input part  432 . Then, as shown in the part (K) in  FIG. 8 , the signal voltage Vcmp, which is obtained by combining together the voltage retained in the fourth sampling capacitor Cs 4  and the search signal Vramp 2  provided by the search signal input part  432 , is fed into the first input terminal (−) of the second opamp  431 . In the second opamp  431 , comparison is made between the input signal voltage Vcmp, which is input into the first input terminal (−) through the third sampling capacitor Cs 3 , and the referential potential Vref 2   i , which is fed to the second input terminal (+), and the comparison output signal cmpout at the H level is output as shown in the part (L) in  FIG. 10  until the input signal voltage Vcmp crosses the referential potential Vref 2   i . The time duration until the crossing is measured by a counter, which is not shown, so that AD conversion is performed. 
     The amplifying part  420  receives the read-out reset signal VRST, which has a higher potential than the read-out luminance signal VSIG. The component corresponding to the read-out reset signal VRST has a lower potential (VOS−G*(VRST−VSIG)) than the offset potential VOS by G*(VRST−VSIG) due to the offset-shifting. During a predetermined period of time after the transfer period ends, as shown in the part (G) in  FIG. 10 , the control signal SH remains at the H level, so that the sample holding switch part SW 431  of the AD converting part  430  remains in the conduction state. As a result, the output signal (amplified output) ampout from the first opamp  421  of the amplifying part  420  becomes the signal (VOS−G*(VRST−VSIG)), is transferred to the AD converting part  430  through the sample holding switch part SW 431  and is retained in the fourth sampling capacitor Cs 4 . 
     At this point, as shown in the part (J) in  FIG. 10 , the second search signal Vramp 2  having a positive slope waveform is fed to the AD converting part  430  through the search signal input part  432 . Then, as shown in the part (K) in  FIG. 10 , the signal voltage Vcmp, which is obtained by combining together the voltage retained in the fourth sampling capacitor Cs 4  and the search signal Vramp 2  provided by the search signal input part  432  is fed into the first input terminal (−) of the second opamp  431 . In the second opamp  431 , comparison is made between the input signal voltage Vcmp, which is input into the first input terminal (−) through the third sampling capacitor Cs 3  and the referential potential Vref 2   i , which is fed to the second input terminal (+), and the comparison output signal cmpout at the H level is output as shown in the part (L) in  FIG. 10  until the input signal voltage Vcmp crosses the referential potential Vref. The time duration until the crossing is measured by a counter, which is not shown, so that AD conversion is performed. 
     The comparison output signal cmpout exhibits the same result as in the above-described rolling shutter mode. 
     Additionally, the column reading circuit  40 , which constitutes part of, for example, the reading part  70 , calculates the difference {VSIG−VRST} between the read-out reset signal VRST and the read-out luminance signal VSIG and performs the CDS. 
     As described above, in the first embodiment, the solid-state imaging device  10  includes the pixel part  20  having pixels for performing photoelectric conversion arranged therein and the column reading circuit  40  having AD (analog-to-digital) conversion function for analog-to-digital converting the pixel signals read out from the pixels to the vertical signal lines. In the solid-state imaging device  10 , the pixel signal read out from the pixel is at least either one of the first pixel signal pixout 1  and the second pixel signal pixout 2 . The first pixel signal pixout 1  includes the read-out reset signal VRST and the read-out luminance signal read out in the stated order from the pixels using a rolling shutter or first operation. The second pixel signal pixout 2  includes the read-out luminance signal VSIG and the read-out reset signal VRST read out in the stated order from the pixel using a global shutter or second operation. The column reading circuit  40  includes the amplifying part  420  for amplifying the pixel signal and the AD converting part  430  for analog-to-digital converting the pixel signal amplified by the amplifying part  420 , in connection with the search signal. The first search signal Vramp 1  for the first pixel signal pixout 1  and the second search signal Vramp 2  for the second pixel signal pixout 2  can be configured such that their search levels are inverted. 
     Accordingly, in the first embodiment, the column reading circuit  40  is capable of operating in different operational modes and processing read-out signals of different signal types using a single reading circuit which can eventually realize reduced circuit scale, less complicated control and lower power consumption. The first embodiment is particularly advantageous in that a reduced area can be achieved since it is not necessary to add a sample holding circuit to the pixels that are capable of producing pixel signals in both a low-noise rolling shutter mode, where the reset level is output first, and a global shutter mode, where no distortion is created due to a moving subject, and that the processing can be carried out at low voltage. To be specific, in the first opamp  421 , which is a column amplifier, the first switch part SW 421  and a bias signal line are added. The first switch part SW 421  is capable of switching the connection target of the first feedback capacitor Cf 1  between the output terminal of the first opamp  421  and the offset potential VOS, depending on whether the mode is the single-ended rolling shutter mode and the single-ended global shutter mode. The addition is the only change needed to be made in order to use the single reading circuit for different operational modes and read-out signals of different signal types. 
     Furthermore, in the solid-state imaging device  10  relating to the first embodiment, the pixel part  20  has pixels including a first pixel  21  that has a photoelectric conversion reading part and a signal retaining part and a second pixel  22  that has a photoelectric conversion reading part. With such configuration, the solid-state imaging device  10  is capable of operating both in a rolling shutter mode or a first operation and a global shutter more or a second operation. The solid-state imaging device  10  is configured, for example, as a stacked CMOS image sensor. In the solid-state imaging device  10  relating to the first embodiment, the pixel part  20  includes the first pixel array  230  in which the photoelectric conversion reading parts  211  of the plurality of first pixels  21  are arranged in a matrix pattern, the retaining part array  240  in which the signal retaining parts  212  of the plurality of first pixels  21  are arranged in a matrix pattern, and the second pixel arrays  250 - 1 ,  250 - 2  in which the photoelectric conversion reading parts of the plurality of second pixels are arranged in a matrix pattern. In the rolling shutter mode or first operation, the read-out signals from the photoelectric conversion reading parts  211 ,  221  of the first and second pixels  21  and  22  are directly output to the first vertical signal lines LSGN 11  without traveling through the bypass paths. In the global shutter mode or second operation, the retaining signals of the signal retaining parts  212  of the first pixels  21  are output to the second vertical signal lines LSGN 12 . 
     Accordingly, the solid-state imaging device  10  relating to the first embodiment can prevent the increase in the configuration complexity and the reduction in area efficiency from the perspective of layout. 
     Furthermore, the solid-state imaging device  10  relating to the first embodiment can produce an image signal having a desired aspect ratio, which depends on the operational mode. 
     The solid-state imaging device  10  relating to the first embodiment has a stacked structure of the first substrate (an upper substrate)  110  and the second substrate (a lower substrate)  120 . In the first substrate  110 , the first pixel array  230  is formed and centered around the central portion of the first substrate  110 . In the first pixel array  230 , the photoelectric conversion reading parts  211  of the first pixels  21  of the pixel part  20  are arranged. On both (upper and lower) sides of the first pixel array  230  in the extending direction of the first vertical signal line LSGN 11 , the second pixel arrays  250 - 1 ,  250 - 2  are formed. In the first substrate  110 , the first vertical signal line LSGN 11  is also formed. In the second substrate  120 , the retaining part array  240  (region  121 ) is formed and centered around the central portion of the second substrate  120 , and the second vertical signal line LSGN 12  is also formed. In the retaining part array  240 , the signal retaining parts  212  of the first pixels  21 , which are connected to the output nodes ND 21  of the photoelectric conversion reading parts  211  of the first pixel array  230 , are arranged in a matrix pattern. Around the retaining part array  240 , regions  122 ,  123  are formed for the column reading circuit  40 , for example. 
     Accordingly, the first embodiment can maximize the value per cost since the first substrate  110  is basically formed only with NMOS elements and the first pixel array and the second pixel arrays can increase the effective pixel region to the maximum. 
     Second Embodiment 
       FIG. 11  shows an example configuration of pixels and a column reading circuit of a solid-state imaging device relating to a second embodiment of the present invention. 
     The solid-state imaging device  10 A relating to the second embodiment differs from the solid-state imaging device  10  relating to the above-described first embodiment in the following points. In the solid-state imaging device  10 A relating to the second embodiment, the first pixel signal output to the column reading circuit  40 A in the rolling shutter mode is provided as a differential pixel signal, in place of a single-ended pixel signal. 
     Specifically speaking, the first pixel signal pixout 1  transferred through the first vertical signal line LSGN 11  is fed, through the first sampling capacitor Cs 1 , to the first input terminal (−) of the first opamp  421  of the amplifying part  420  through the input part  440  of the column reading circuit  40 A. The other signal traveling to the connection line between the current source Ibias 1  and the reference potential VSS is fed, through the second sampling capacitor Cs 2 , to the second input terminal (+) of the first opamp  421  of the amplifying part  420  through the input part  440 . 
     The remaining features of the solid-state imaging device  10 A relating to the second embodiment are the same as the counterparts of the solid-state imaging device  10  relating to the first embodiment. 
     More specifically, in the differential rolling shutter mode period, the third mode signal MOD 3  is fed to the input part  440  of the column reading circuit  40 A. In addition, in the rolling shutter mode period, the control signal CKOS at the L level is fed to the first switch part SW 421  of the amplifying part  420  of the column reading circuit  40 A. In this way, the terminals a and b of the first switch part SW 421  are connected, so that the first feedback capacitor Cf 1  is connected between the first input terminal (−) of the first opamp  421  and the output node ND 421 . In addition, in the rolling shutter mode period, the control signal VREFSH is fed to the second switch part SW 422  of the amplifying part  420  of the column reading circuit  40 A as a clock. 
       FIG. 12  is a timing chart including parts (A) to (K) to illustrate the reading operation performed mainly by the column reading circuit of the solid-state imaging device relating to the second embodiment of the present invention in the differential rolling shutter mode. 
     In  FIG. 12 , the part (A) shows the control signal SEL for the selection transistor SEL 1 -Tr of the photoelectric conversion reading part  211  of the first pixel  21  and the selection transistor SEL 2 -Tr of the photoelectric conversion reading part  221  of the second pixel  22 . In  FIG. 12 , the part (B) shows the control signal RST for the reset transistor RST 1 -Tr of the photoelectric conversion reading part  211  of the first pixel  21  and the reset transistor RST 2 -Tr of the photoelectric conversion reading part  221  of the second pixel  22  and the control signal TG for the transfer transistors TG 1 -Tr, TG 2 -Tr. In  FIG. 12 , the part (C) shows the single-ended first pixel signal pixout 1  produced in the global shutter mode, the part (D) shows the control signal AZ 1  for the autozero switch part SW 423  and the control signal VREFSH for the second switch part SW 422 , the part (E) shows the control signal CKOS for the first switch part SW 421 , the part (F) shows the control signal SH for the sample holding switch part SW 431 , and the part (G) shows the control signal AZ 2  for the autozero switch part SW 432 . In  FIG. 12 , the part (H) shows the output signal (amplified output) ampout from the first opamp  421 , the part (I) shows the first search signal Vramp 1 , the part (J) shows the input signal voltage Vcmp into the second opamp  431 , and the part (K) shows the output signal (comparison output) cmpout from the second opamp  431 . 
     The reading operation performed in the pixels and the column reading circuit  40 A in the differential rolling shutter mode is the same as the reading operation performed in the pixels and the column reading circuit  40  in the single-ended rolling shutter mode, which has been described with reference to  FIG. 8  including the parts (A) to (L), except for that the control signal VREFSH transits in a similar manner to the control signal AZ 1 . Therefore, the reading operation is not described in detail here. 
     The second embodiment can not only produce the same effects as the above-described first embodiment but also can cancel the column-wise ground (GND) floating in the rolling shutter pixels and eventually reduce noise such as shading, since one of the signals traveling to the connection line between the current source Ibias 1  and the reference potential VSS is fed, through the second sampling capacitor Cs 2 , to the second input terminal (+) of the first opamp  421  of the amplifying part  420  through the input part  440 . Alternatively, the pixels may operate in the global shutter mode. Specifically speaking, the second pixel signal pixout 2  output from the second vertical signal line LSGN 12  is fed, through the first sampling capacitor Cs 1 , to the first input terminal (−) of the first opamp  421  of the amplifying part  420  through the input part  440  of the column reading circuit  40 A. The other signal traveling to the connection line between the current source Ibias 1  and the reference potential VSS is fed, through the second sampling capacitor Cs 2 , to the second input terminal (+) of the first opamp  421  of the amplifying part  420  through the input part  440 . In this case, noise such as shading can be also reduced in the global shutter pixels. 
     Third Embodiment 
       FIG. 13  shows an example configuration of a first pixel of a solid-state imaging device relating to a third embodiment of the present invention. 
     The solid-state imaging device  10 B relating to the third embodiment differs from the solid-state imaging devices  10 ,  10 A relating to the above-described first and second embodiments in terms of the configurations of the signal retaining part  212 B in the first pixel  21 B. 
     The signal retaining part  212 B of the first pixel  21  basically includes an input part  2121  connected to a constant current source Ibias 3 , a sample holding part  2122 B, an output part  2123 B, and nodes ND 22 , ND 25 -ND 27 . 
     The constant current source Ibias 3  is connected between the node ND 22  and the reference potential VSS and controlled to remain on, for example, during a predetermined period of time within a global shutter period. 
     In place of the constant current source Ibias 3 , a switch element may be provided, which is connected between the node ND 22  and the reference potential VSS and controlled to remain on, for example, during a predetermined period of time within a global shutter period. 
     The sample holding part  2122 B includes switch elements SSW 22  to SW 24 , a reset sample-and-hold capacitor CR 21 , a sample-and-hold capacitor CS 21 , and nodes ND 25  to ND 27 . 
     The switch element SW 22  selectively maintains the connection between the sample-and-hold capacitor CS 21  of the sample holding part  21228  and the output node ND 21  of the photoelectric conversion reading part  211  through the node ND 26  during a global shutter period or second period. The terminal a of the switch element SW 22  is connected to the input node ND 22 , which is connected to a third signal line LSGN 13 , and the terminal b of the switch element SW 22  is connected to the node ND 26 . The terminals a and b of the switch element SW 22  are kept connected and the switch element SW 22  is in the conduction state during the period in which, for example, the control signal GSHS is at the high level. The sample-and-hold capacitor CS 21  is connected between the node ND 26  and the node ND 27  connected to the reference potential VSS. 
     The switch element SW 23  selectively maintains the connection between the reset sample-and-hold capacitor CR 21  of the sample holding part  21228  and the output node ND 21  of the photoelectric conversion reading part  211  through the node ND 25  during a global shutter period or second period. The terminal a of the switch element SW 23  is connected to the input node ND 22 , which is connected to the third signal line LSGN 13 , and the terminal b of the switch element SW 23  is connected to the node ND 25 . The terminals a and b of the switch element SW 23  are kept connected and the switch element SW 22  is in the conduction state during the period in which, for example, the control signal GSHR is at the high level. The reset sample-and-hold capacitor CR 21  is connected between the node ND 25  and the node ND 27  connected to the reference potential VSS. 
     The switch element SW 24  maintains the connection between the node ND 25  connected to the reset sample-and-hold capacitor CR 21  and the node ND 26  connected to the sample-and-hold capacitor CS 21  during the global shutter period or second period. The terminal a of the switch element SW 24  is connected to the node ND 26 , and the terminal b of the switch element SW 24  is connected to the node ND 25 . The terminals a and b of the switch element SW 24  are kept connected and the switch element SW 24  is in the conduction state during the period in which, for example, the control signal CKST is at the high level. This can average the reset level and the signal level of the selected row. 
     The switch elements SW 22  to SW 24  are formed by MOS transistors, for example, n-channel MOS (NMOS) transistors. 
     The output part  2123 B includes a source follower transistor SF 3 S-Tr for basically outputting the signal retained in the sample-and-hold capacitor CS 21  at a level determined by the retained voltage in the global shutter period or second period, and outputs the retained signal selectively through the selection transistor SEL 3 S-Tr, to a second vertical signal line LSGN 12 - 1 , which is to be driven by a constant current source Ibias 1 - 1 . 
     The source follower transistor SF 3 S-Tr and the selection transistor SEL 3 S-Tr are connected in series between the power supply line Vdd and the second vertical signal line LSGN 12 - 1 , which is to be driven by the constant current source Ibias 1 - 1 . 
     The gate of the source follower transistor SF 3 S-Tr is connected to the node ND 26 , and the selection transistor SEL 3 S-Tr is controlled by a control signal SEL 3  applied to the gate through a control line. The selection transistor SEL 3 S-Tr remains selected and in the conduction state during a selection period in which the control signal SEL 3  is at the H level. This causes the source follower transistor SF 3 S-Tr to output, to the second vertical signal line LSGN 12 - 1 , the read-out voltage (VRST, VSIG) of a column output corresponding to the average voltage or the retained voltage in the sample-and-hold capacitor CS 21 . 
     Furthermore, the output part  2123 B includes a source follower transistor SF 3 R-Tr for basically outputting the signal retained in the reset sample-and-hold capacitor CR 21  at a level determined by the retained voltage in the global shutter period or second period, and outputs the retained signal selectively through the selection transistor SEL 3 R-Tr, to the second vertical signal line LSGN 12 - 2 , which is to be driven by a constant current source Ibias 1 - 2 . 
     The source follower transistor SF 3 R-Tr and the selection transistor SEL 3 R-Tr are connected in series between the power supply line Vdd and the second vertical signal line LSGN 12 - 2 , which is to be driven by the constant current source Ibias 1 - 2 . 
     The gate of the source follower transistor SF 3 R-Tr is connected to the node ND 25 , and the selection transistor SEL 3 R-Tr is controlled by a control signal SEL 3  applied to the gate through a control line. The selection transistor SEL 3 R-Tr remains selected and in the conduction state during a selection period in which the control signal SEL 3  is at the H level. This causes the source follower transistor SF 3 R-Tr to output, to the second vertical signal line LSGN 12 - 2 , the read-out voltage (VRST, VSIG) of a column output corresponding to the average voltage or the retained voltage in the reset sample-and-hold capacitor CR 21 . 
     (Reading Operation in the Differential Global Shutter Mode) 
     The following describes the reading operation in the differential global shutter mode.  FIG. 14  is a timing chart including parts (A) to (F) to illustrate the reading operation performed mainly by the pixel part of the solid-state imaging device relating to the third embodiment of the present invention in the global shutter mode.  FIG. 15  is a timing chart including parts (A) to (L) to illustrate the reading operation performed mainly by the column reading circuit of the solid-state imaging device relating to the third embodiment of the present invention in the global shutter mode. 
     In  FIG. 14 , the part (A) shows the control signal TG for the transfer transistor TG 1 -Tr of the photoelectric conversion reading part  211  of the first pixel  21 . In  FIG. 14 , the part (B) shows the control signal RST for the reset transistor RST 1 -Tr of the photoelectric conversion reading part  211  of the first pixel  21 . In  FIG. 14 , the part (C) shows the control signal GSHS for the switch element SW 22  of the signal retaining part  212 B of the first pixel  21 . In  FIG. 14 , the part (D) shows the control signal GSHR for the switch element SW 23  of the signal retaining part  212 B of the first pixel  21 . In  FIG. 14 , the part (E) shows the control signal CKST for the switch element SW 24  of the signal retaining part  212 B of the first pixel  21 . In  FIG. 14 , the part (F) shows the control signal SEL 3  for the selection transistor SEL 3 -Tr of the signal retaining part  212  of the first pixel  21 . 
     In  FIG. 15 , the part (A) shows the equivalent circuit of the pixel and the column reading circuit, and the part (B) shows the control signal SEL 3  for the selection transistors SEL 3 R-Tr, SEL 3 S-Tr of the signal retaining part  212 B of the first pixel  21 . In  FIG. 15 , the part (C) shows the control signal CKST for the switch element SW 24  of the signal retaining part  212 B of the first pixel  21 . In  FIG. 15 , the part (D) shows the differential second pixel signal pixout 2  produced in the global shutter mode, the part (E) shows the control signal AZ 1  for the autozero switch part SW 423  and the control signal VREFSH for the second switch part SW 422 , the part (F) shows the control signal CKOS for the first switch part SW 421 , the part (G) shows the control signal SH for the sample holding switch part SW 431 , and the part (H) shows the control signal AZ 2  for the autozero switch part SW 432 . In  FIG. 15 , the part (I) shows the output signal (amplified output) ampout from the first opamp  421  and the feedback signal ampvst, the part (J) shows the first search signal Vramp 1 , the part (K) shows the input signal voltage Vcmp into the second opamp  431 , and the part (L) shows the output signal (comparison output) cmpout from the second opamp  431 . 
     In the global shutter mode, the control signal SEL for the selection transistor SEL 1 -Tr of the photoelectric conversion reading part  211  of the first pixel  21  and the selection transistor SEL 2 -Tr of the photoelectric conversion reading part  221  of the second pixel  22  remains at the low level (L) during the entire global shutter period. This suspends (stops) the voltage signals from being output from the first pixel array  230  and the second pixel arrays  250 - 1 ,  250 - 2  to the first vertical signal line LSGN 11  during the entire global shutter period. Accordingly, the second pixel arrays  250 - 1 ,  250 - 2  are controlled to remain in the non-activated state. On the other hand, the first pixel array  230  is in the activated state, so that the voltage signal can be output from the output node ND 21  to the signal retaining part  2128 . 
     Referring to the parts (A) to (F) in  FIG. 14 , the period starting at the timing t 21  and ending at the timing t 24  denotes the period Tint of resetting the photodiodes PD 21  and the floating diffusions FD 21  in all of the photoelectric conversion reading parts  211  in the first pixel array  230  and storing the charges. 
     In this reset and charge storage period, the control signals GSHS, GSHR, CKST for the switch elements SW 22  to SW 24 , which are designed to control the driving of all of the signal retaining parts  2128  of the retaining part array  240 , and the control signal SEL 3  for controlling the selection transistor SEL 3 -T remain at the L level, so that the switch elements SW 22  to SW 24 , and the selection transistor SEL 3 -Tr remain in the non-conduction state and the constant current source Ibias 3  is controlled to remain in the off state. 
     While these states are maintained, in the reset period, the reset transistor RST 1 -Tr remains selected and in the conduction state during the period in which the control signal RST is at the H level. While the control signal RST remains at the H level, the transfer transistor TG 1 -Tr remains selected and in the conduction state during the period in which the control signal TG is at the H level, so that the node at which the charges (electrons) obtained by the photoelectric conversion in the photodiode PD 21  are stored is in the conduction state with the floating diffusion FD 21 . This resets the photodiode PD 21  and the floating diffusion FD 21  to the potential of the power supply line Vdd. 
     After the photodiode PD 21  is reset, the control signal TG for the transfer transistor TG 1 -Tr is switched to the L level, so that the transfer transistor TG 1 -Tr is brought into the non-conduction state, and the charges obtained by the photoelectric conversion start to be stored in the photodiode PD 21 . To do so, the control signal RST for the reset transistor RST 1 -Tr is kept at the H level, so that the floating diffusion FD 21  is kept being reset to the potential of the power supply line Vdd. While these states are maintained, at the timing t 22 , the source follower transistor SF 1 -Tr in each photoelectric conversion reading part  211  converts the charges in the floating diffusion FD 21  into a voltage signal representing the quantity of the charges and outputs the voltage signal from the output node ND 21  as the read-out reset signal VRST of a column output. Subsequently, to end the reset period, after the timing t 22  is passed, the control signal RST for the reset transistor RST 1 -Tr is switched to the L level, so that the reset transistor RST 1 -Tr is brought into the non-conduction state. After this, during a predetermined period of time including the timing t 23 , the control signal GSHS for the switch element SW 22  in the signal retaining part  212 B of the first pixel  21  and the control signal GSHR for the switch element SW 23  remain at the H level, so that the sample-and-hold capacitor CS 21  and the reset sample-and-hold capacitor CR 21  are initialized. Additionally, the constant current source Ibias 3  is controlled to remain in the on state. During a predetermined period of time including the timing t 23 , the read-out reset signal VRST output from the output node ND 21  of each photoelectric conversion reading part  211  is transferred to the corresponding signal retaining part  212 B through the third signal line LSGN 13  and retained in the reset sample-and-hold capacitor CR 21  through the switch element SW 23 . After this, the control signal GSHS for the switch element SW 22  in the signal retaining part  212 B of the first pixel  21 B and the control signal GSHR for the switch element SW 23  are switched to the L level, so that the switch elements SW 22  and SW 23  are brought into the non-conduction state. 
     Here, a predetermined period of time including the timing t 24  is referred to as the transfer period. In the transfer period, the transfer transistor TG 1 -Tr in each photoelectric conversion reading part  211  remains selected and in the conduction state during the period in which the control signal TG is at the H level, so that the charges (electrons) produced by the photoelectric conversion and then stored in the photodiode PD 21  are transferred to the floating diffusion FD 21 . After the transfer period ends, the control signal TG for the transfer transistor TG 1 -Tr is switched to the L level, so that the transfer transistor TG 1 -Tr is brought into the non-conduction state. 
     Concurrently with the timing at which the control signal TG for the transfer transistor TG 1 -Tr is switched to the L level in the photoelectric conversion reading part  211  and the transfer period ends, the following control is performed in every signal retaining part  212 B in the retaining part array  240 . In the signal retaining part  212 B, during a predetermined period of time including a timing t 25 , the control signal GSHS remains at the H level and the switch element SW 22  remains in the conduction state, so that the constant current source Ibias 3  is controlled to remain in the on state. 
     In this way, during the predetermined period of time including the timing t 25 , the read-out luminance signal VSIG output from the output node ND 21  of each photoelectric conversion reading part  211  is transferred to the corresponding signal retaining part  212  through the third signal line LSGN 13  and retained in the sample-and-hold capacitor CS 21  through the switch element SW 22 . 
     After the read-out luminance signal VSIG is retained in the sample-and-hold capacitor CS 21 , the control signal GSHS is switched to the L level, so that the switch element SW 22  is brought into the non-conduction state. 
     In order to read the signal that has been retained in the above-described manner, a given one of the rows in the retaining part array  240  is selected. To make such a selection, the control signal SEL 3  for the selection transistors SEL 3 -Tr in the selected row is set to the H level, so that these selection transistors SEL 3 S-Tr and SEL 3 R-Tr are brought into the conduction state. At the timing t 26 , the read-out luminance signal VSIG retained in the sample-and-hold capacitor CS 21  is read, and, at the same time, the read-out reset signal VRST retained in the reset sample-and-hold capacitor CR 21  is read. 
     More specifically, in each signal retaining part  2128 , the source follower transistor SF 3 S-Tr, whose gate is connected to the node ND 26 , outputs the read-out luminance signal VSIG of a column output to the second vertical signal line LSGN 12 - 1  at a level corresponding to the retained voltage in the sample-and-hold capacitor CS 21  connected to the node ND 26 . The read-out luminance signal VSIG is fed to the column reading circuit  40 . Likewise, in each signal retaining part  2128 , the source follower transistor SF 3 R-Tr, whose gate is connected to the node ND 25 , outputs the read-out reset signal VRST of a column output to the second vertical signal line LSGN 12 - 2  at a level corresponding to the retained voltage in the reset sample-and-hold capacitor CR 21  connected to the node ND 25 . The read-out reset signal VRST is fed to the column reading circuit  40 . 
     After this, in the signal retaining part  212 B, during a predetermined period of time including the timing t 27 , the control signal CKST remains at the H level, so that the switch element SW 24  remains in the conduction state. This can average the reset level and the signal level for the selected row. At the timing t 28 , the read-out luminance signal VSIG retained in the sample-and-hold capacitor CS 21  and the read-out reset signal VRST retained in the reset sample-and-hold capacitor CR 21  are averaged and the signals are read out in parallel. 
     More specifically, in each signal retaining part  2128 , the source follower transistor SF 3 S-Tr, whose gate is connected to the node ND 26 , outputs an averaged signal of a column output to the second vertical signal line LSGN 12 - 1  at a level corresponding to the averaged voltage in the node ND 26 . The averaged signal is fed to the column reading circuit  40 . Likewise, in each signal retaining part  2128 , the source follower transistor SF 3 R-Tr, whose gate is connected to the node ND 25 , outputs an averaged signal AVSR of a column output to the second vertical signal line LSGN 12 - 2  at a level corresponding to the averaged voltage in the node ND 25 . The averaged signal AVSR is fed to the column reading circuit  40 . 
     Here, the following expressions can be obtained, where V OS1 , V OS2  respectively denote the offsets of the source follower transistors SF 3 S-Tr, SF 3 R-Tr for outputting the signal level Vs and the reset level V R  that are read out from the signal retaining part  2128 . 
     
       
         
           
             
               
                 
                   
                     
                       
                         
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     Here, V OUTR (t 26 ) denotes the reset signal voltage read out at the timing t 26 , V OUTS (t 26 ) denotes the signal voltage read out at the timing t 26 , V OUTR (t 28 ) denotes the reset signal voltage read out at the timing t 28 , and V OUTS (t 28 ) denotes the signal voltage read out at the timing t 28 . 
     In the above-described manner, the offsets of the source follower transistors SF 3 S-Tr, SF 3 R-Tr can be canceled by the CDS processing performed on the differential signals in the circuit of the later stage. 
     In the column reading circuit  40 , which constitutes part of, for example, the reading part  70 , the read-out luminance signal VSIG and the read-out reset signal VRST that are read out concurrently in parallel at the timing t 26  and the averaged signal AVSR that is read out at the timing t 28  are in parallel fed to the amplifying part  420  as the second pixel signal pixout 2 . 
     In the column reading circuit  40 , which constitutes part of, for example, the reading part  70 , the read-out luminance signal VSIG and the read-out reset signal VRST and the averaged signal AVSR of the second pixel signal pixout 2  that are fed concurrently in parallel through the input part  440  are subjected to amplification and AD conversion, and the difference between the signals {VRST-VSIG-AVSR)} is calculated so that the CDS is performed. 
     More specifically, in the differential global shutter mode period, the fourth mode signal MOD 4  is fed to the input part  440  of the column reading circuit  40 . In addition, in the differential global shutter mode period, the control signal CKOS at the L level is fed to the first switch part SW 421  of the amplifying part  420  of the column reading circuit  40 . In this way, the terminals a and b of the first switch part SW 421  are connected, so that the first feedback capacitor Cf 1  is connected between the first input terminal (−) of the first opamp  421  and the output node ND 421 . In addition, in the differential global shutter mode period, the control signal VREFSH is fed as a clock to the second switch part SW 422  of the amplifying part  420  of the column reading circuit  40 . 
     While these states are maintained, the second pixel signal pixout 2  is input into the input part  440 , and the second pixel signal pixout 2   d   1 , which is one of the differential signals obtained in the global shutter mode, is fed from the first output terminal TO 1  of the input part  440  to the first input terminal (−) of the first opamp  421 , which is connected to the first sampling capacitor Cs 1 . In parallel with this, the second pixel signal pixout 2   d   2 , which is the other of the differential signals obtained in the global shutter mode, is fed from the second output terminal TO 2  of the input part  440  to the second input terminal (+) of the first opamp  421 , which is connected to the second sampling capacitor Cs 2 . 
     During a predetermined period of time after the read-out luminance signal VSIG and the read-out reset signal VRST are input, the control signal AZ 1  and the control signal VREFSH remain at the H level, as shown in the part (E) in  FIG. 15 . In this way, the autozero switch part SW 423  and the switch part SW 422  of the amplifying part  420  remain in the conduction state. This resets the first opamp  421  of the amplifying part  420 . As a result, the output signal (amplified output) ampout from the first opamp  421  of the amplifying part  420  becomes equal to a predetermined DC potential, for example, the referential potential Vref. 
     During a predetermined period of time after the control signal AZ 1  and the control signal VREFSH are switched to the L level, the control signals SH and AZ 2  remain at the H level as shown in the parts (G) and (H) in  FIG. 15 . In this way, the sample holding switch part SW 431  and the autozero switch part SW 432  of the AD converting part  430  remain in the conduction state. The lengths of the durations in which the control signals SH and AZ 2  remain at the H level decrease in the order of the control signals SH and AZ 2 . This resets the second opamp  431  of the AD converting part  430 . 
     As a result, the output signal (amplified output) ampout from the first opamp  421  of the amplifying part  420  becomes equal in level to the referential potential Vref, is transferred to the AD converting part  430  through the sample holding switch part SW 431  and retained in the third sampling capacitor Cs 3  and the fourth sampling capacitor Cs 4 . 
     At this point, as shown in the part (J) in  FIG. 15 , the first search signal Vramp 1  having a negative slope waveform is fed to the AD converting part  430  through the search signal input part  432 . Then, as shown in the part (K) in  FIG. 15 , the signal voltage Vcmp, which is obtained by combining together the voltage retained in the fourth sampling capacitor Cs 4  and the search signal Vramp 1  provided by the search signal input part  432  is fed into the first input terminal (−) of the second opamp  431 . In the second opamp  431 , comparison is made between the input signal voltage Vcmp, which is input into the first input terminal (−) through the third sampling capacitor Cs 3 , and the referential potential Vref 2 , which is fed to the second input terminal (+), and the comparison output signal cmpout at the H level is output as shown in the part (L) in  FIG. 15  until the input signal voltage Vcmp crosses the referential potential Vref 2 . The time duration until the crossing is measured by a counter, which is not shown, so that AD conversion is performed. 
     Subsequently, the averaged signal AVSR, which is obtained by processing the read-out luminance signal VSIG and the read-out reset signal VRST, is fed to the amplifying part  420 . The output signal ampout from the first opamp  4211  is now the signal (Vref+G*(VRST−VSIG)) obtained by amplifying the referential potential Vref by the result of multiplying the difference between the read-out reset signal voltage VRST and the read-out luminance signal VSIG having a lower potential by the capacitance ratio G. The feedback signal ampvst has a potential (Vref+G′*(VRST−VSIG)). During a predetermined period of time after the transfer period ends, as shown in the part (G) in  FIG. 15 , the control signal SH remains at the H level and the sample holding switch part SW 431  of the AD converting part  430  remains in the conduction state. As a result, the output signal (amplified output) ampout from the first opamp  421  of the amplifying part  420  is the signal (Vref+G*(VRST−VSIG)), transferred to the AD converting part  430  through the sample holding switch part SW 431  and retained in the fourth sampling capacitor Cs 4 . 
     At this point, as shown in the part (J) in  FIG. 15 , the first search signal Vramp 1  having a negative slope waveform is fed to the AD converting part  430  through the search signal input part  432 . Then, as shown in the part (K) in  FIG. 15 , the signal voltage Vcmp, which is obtained by combining together the voltage retained in the fourth sampling capacitor Cs 4  and the search signal Vramp 1  provided by the search signal input part  432  is fed into the first input terminal (−) of the second opamp  431 . In the second opamp  431 , comparison is made between the input signal voltage Vcmp, which is input into the first input terminal (−) through the third sampling capacitor Cs 3 , and the referential potential Vref 2 , which is fed to the second input terminal (+), and the comparison output signal cmpout at the H level is output as shown in the part (L) in  FIG. 15  until the input signal voltage Vcmp crosses the referential potential Vref 2 . The time duration until the crossing is measured by a counter, which is not shown, so that AD conversion is performed. 
     Subsequently, the column reading circuit  40 , which constitutes part of, for example, the reading part  70 , calculates the difference {VRST−VSIG−AVSR)} between the read-out reset signal VRST and the read-out luminance signal VSIG and performs digital CDS. 
     The following describes the CDS processing through the column reading circuit relating to the third embodiment with reference to the parts (A) to (L) in  FIG. 15 . Referring to the parts (A) to (L) in  FIG. 15 , an example case is shown where, at the timing t 31 , the read-out luminance signal VSIG and the read-out reset signal VRST are read concurrently in parallel from the signal retaining part  2128  in the first pixel  21  and input into the first opamp  421  in the column reading circuit  40 . Similarly, referring to the parts (A) to (L) in  FIG. 15 , an example case is shown where, at the timing t 32 , the averaged signal AVSR and, the read-out luminance signal VSIG and the read-out reset signal VRST are read concurrently in parallel from the signal retaining part  212 B in the first pixel  21  and input into the column reading circuit  40 . 
     The following expression represents the input signal Vinp(t 31 ) input into the second input terminal (+) of the first opamp  421  at the timing t 31 .
 
 V inp( t 31)= V ref+( Qinj /( Cs+Cf ))≅ V ′ref  [Mathematical Expression 2]
 
     The following expression is given in relation to the input signal Vinn(t 31 ) input into the first input terminal (−) of the first opamp  421  at the timing t 31 .
 
 Cs ×( V ′ref− Vrst )+ Cf× 0 +Qinj=Cs ×( V ′ref− Vrst )+ Cf ×( V ′ref− V out)  [Mathematical Expression 3]
 
     Accordingly, the following expression represents the output Vout(t 31 ) at the timing t 31 .
 
 V out( t 31)= V ′ref− Qinj/Cf   [Mathematical Expression 4]
 
     The following expression is given in relation to the input signal Vinp(t 32 ) input into the second input terminal (+) of the first opamp  421  at the timing t 32 .
 
 Cs ×( V ′ref− Vrst )+ Cf×V ′ref= Cs ×( V inp−( Vrst+Vsig )/2)+ Cf×V inp  [Mathematical Expression 5]
 
     Accordingly, the following expression represents the input signal Vinp(t 32 ) input into the second input terminal (+) of the first opamp  421  at the timing t 32 .
 
 V inp( t 32)= V ′ref+( Cs /( Cs+Cf ))×( Vrst−VsiG )/2  [Mathematical Expression 6]
 
     The following expression is given in relation to the input signal Vinn(t 31 ) input into the first input terminal (−) of the first opamp  421  at the timing t 32 .
 
 Cs ×( V ′ref− Vrst )+ Cf× 0 +Qinj=Cs ×( V inp−( Vrst+Vsig )/2)+ Cf ×( V inp− V out)  [Mathematical Expression 7]
 
     Accordingly, the following expression represents the output Vout(t 32 ) at the timing t 32 .
 
 V out( t 32)= V ′ref−( Qinj/Cf )+( Cs/Cf )×( Vrst−Vsig )  [Mathematical Expression 8]
 
     Accordingly, the following expression represents the differential output resulting from the digital CDS processing.
 
 V out( t 32)− V out( t 31)=( Cs/Cf )×( Vrst−Vsig )  [Mathematical Expression 9]
 
     As described above, subjecting the differential signals to the CDS processing can result in outputting of the difference between the read-out luminance signal VSIG and the read-out reset signal VRST. Although the above-described expressions do not clearly say, subjecting the averaged signal AVSR produced from the read-out luminance signal VSIG and the read-out reset signal VRST to the CDS processing can result in canceling the offsets of the source follower transistors SF 3 S-Tr, SF 3 R-Tr. 
     The following specifically describes an example configuration of the first opamp  421  of the column reading circuit  40 . 
       FIG. 16  is a circuit diagram showing an example configuration of the first opamp of the column reading circuit relating to the third embodiment of the present invention.  FIG. 17  illustrates an example of how to control the input range of the first opamp in the differential global shutter mode. 
     The first opamp  421  can be formed using a high-gain opamp of a source-coupled pair input, which is shown in  FIG. 16 , for example. 
     The opamp  421 B in  FIG. 16  includes PMOS transistors PT 41  to PT 44 , NMOS transistors NT 41  to NT 44 , a switch part SW 41 , a current source  141 , and nodes ND 41 , ND 42 . 
     The PMOS transistors PT 41 , PT 42  and the NMOS transistors NT 41 , NT 42  are cascade-connected between the power supply line Vdd of the power supply voltage VDD and the reference potential VSS, and the PMOS transistors PT 43 , PT 44  and the NMOS transistors NT 43 , NT 44  are cascade-connected between the power supply line Vdd of the power supply voltage VDD and the reference potential VSS. The source of the PMOS transistor PT 41  and the source of the PMOS transistor PT 43  are connected to each other, and the connection node therebetween is connected to the power supply line Vdd of the power supply voltage VDD. The source of the NMOS transistor NT 41  and the source of the NMOS transistor NT 43  are connected to each other, and the connection node therebetween is connected to the reference potential VSS and to the current source  141 . 
     The connection point between the drain of the PMOS transistor PT 42  and the drain of the NMOS transistor NT 42  forms the node ND 41 , and the connection point between the drain of the PMOS transistor PT 44  and the drain of the NMOS transistor NT 44  forms the node ND 42 . The node ND 41  is connected to the gates of the PMOS transistors PT 41 , PT 43 , and the node ND 42  is connected to the output node ND 421 . The gates of the PMOS transistors PT 42 , PT 44  are both connected to a feeding terminal Tvbp of the bias potential Vbp. 
     The terminal a of the switch part SW 41  is connected to the gates of the NMOS transistors NT 42 , NT 44 , the terminal b is connected to the power supply line Vdd of the power supply voltage VDD, and the terminal c is connected to the feeding terminal Tvtr of the telescopic potential Vtr. Referring to the switch part SW 41 , the conduction state is maintained between the terminal a and the terminal b when, for example, the control signal CTL is at the L level, and the conduction state is maintained between the terminal a and the terminal c when the control signal CTL is at the H level. 
     When the gain G is set low, the switch part SW 41  controls the gates of the NMOS transistors NT 42 , NT 44  to be connected to the power supply line Vdd of the power supply voltage VDD, so that the first opamp  421  is controlled not to function as, so-called, a telescopic amplifier. This is for allowing a wide input range. When the gain G is set high, the switch part SW 41  controls the gates of the NMOS transistors NT 42 , NT 44  to be connected to the telescopic potential Vtr, so that the first opamp  421  is controlled to function as, so-called, a telescopic amplifier. This is for reducing gain error. 
     According to the example shown in  FIG. 17 , when the gain is low, for example, ×1 or ×2, the gates of the NMOS transistors NT 42 , NT 44  are connected to the power supply line Vdd of the power supply voltage VDD, so that the first opamp  421  is controlled not to function as a telescopic amplifier, since the photon shot noise is dominant over the gain error in the light-incident state. When the gain is high, for example, ×4 or ×8, on the other hand, the gates of the NMOS transistors NT 42 , NT 44  are connected to the telescopic potential Vtr, so that the first opamp  421  is controlled to function as a high-gain telescopic amplifier to reduce the gain error in the light-incident state. since the input range is small. 
     The third embodiment not only produces the effects of the above-described first and second embodiments but also enables the CDS processing of the differential output signals to be carried out without the need of adding a capacitor or the like to the global shutter pixels of the differential output type, or with keeping the required area small. 
     Fourth Embodiment 
       FIG. 18  is a circuit diagram showing an example configuration of a column reading circuit relating to a fourth embodiment of the present invention.  FIG. 19  includes parts (A) and (B) and illustrates an example configuration of a search signal input part compatible with inverted binary search, which is employed in an AD converting part relating to the fourth embodiment of the present invention. 
     A solid-state imaging device  10 C relating to the fourth embodiment differs from the solid-state imaging devices  10 ,  10 A,  10 B relating to the above-described first, second and third embodiments in terms of the configuration of a search signal input part  432 C of an AD converting part  430 C in the column reading circuit  40 C. 
     In the first to third embodiments, the first search signal Vramp 1  is fed into the search signal input part  432  as the search signal Vramp when the mode signal fed to the input part is one of the first mode signal MOD 1  (the single-ended rolling shutter mode), the third mode signal MOD 3  (the differential rolling shutter mode) and the fourth mode signal MOD 4  (the differential global shutter mode). In the first to third embodiments, the second search signal Vramp 2  is fed into the search signal input part  432  as the search signal Vramp when the mode signal fed to the input part is the second mode signal MOD 2  (single-ended global shutter mode). In other words, in the first to third embodiments, the AD converting part  430  employs the first search signal Vramp 1  and the second search signal Vramp 2 , whose levels are inverted with respect to each other. 
     In the fourth embodiment, on the other hand, the AD converting part  430 C is formed as an SAR (successive approximation register) ADC, and the inverted binary search is employed for the feeding of the search signals. 
     The search signal input part  432 C includes a plurality of (x) fourth sampling capacitors Cs 4 - 1  to Cs 4 - x  and a plurality of switch parts SW 432 - 1  to SW 432 - x . The fourth sampling capacitors Cs 4 - 1  to Cs 4 - x  are connected such that one of the electrodes (terminals) of each fourth sampling capacitor is connected to the input node ND 431  of the AD converting part  430 C and the other electrode (terminal) of each fourth sampling capacitor is connected to the terminal a of a corresponding one of the switch parts SW 432 - 1  to SW 432 - x . The terminals b of the switch parts SW 432 - 1  to SW 432 - x  are connected to the referential potential Vref, and the terminals c of the switch parts SW 432 - 1  to SW 432 - x  are connected to the ground GND. 
     When the first pixel signal pixout 1  including the read-out reset signal VRST and the read-out luminance signal VSIG, which are read out in the stated order, is input into the column reading circuit  40 C, the switch parts SW 432 - 1  to SW 432 - x  are controlled by the control signal CTR_SAR to be switched between the referential potential Vref and the ground GND in the stated order alternately. Since the switch parts SW 432 - 1  to SW 432 - x  are controlled by the control signal CTR_SAR to be switched between the referential potential Vref and the ground GND in the stated order alternately as described above, the first pixel signal pixout 1  including the read-out reset signal VRST and the read-out luminance signal VSIG, which are read out in the stated order, can be AD converted, as shown in the part (A) in  FIG. 19 . 
     When the second pixel signal pixout 2  including the read-out luminance signal VSIG and the read-out reset signal VRST, which are read out in the stated order, is input into the column reading circuit  40 C, the switch parts SW 432 - 1  to SW 432 - x  are controlled by the control signal CTR_SAR to be switched between the ground GND and the referential potential Vref in the stated order alternately. Since the switch parts SW 432 - 1  to SW 432 - x  are controlled by the control signal CTR_SAR to be switched between the ground GND and the referential potential Vref in the stated order alternately as described above, the second pixel signal pixout 2  including the read-out luminance signal VSIG and the read-out reset signal VRST, which are read out in the stated order, can be AD converted, as shown in the part (B) in  FIG. 19 . 
     The fourth embodiment can produce the same effects as the above-described first, second and third embodiments. 
     The solid-state imaging devices  10 ,  10 A to  10 C described above can be applied, as an imaging device, to electronic apparatuses such as digital cameras, video cameras, mobile terminals, surveillance cameras, and medical endoscope cameras. 
       FIG. 20  shows an example of the configuration of an electronic apparatus including a camera system to which the solid-state imaging device according to the embodiments of the present invention is applied. 
     As shown in  FIG. 20 , the electronic apparatus  300  includes a CMOS image sensor  310 , which can be constituted by any of the solid-state imaging devices  10 ,  10 A to  10 C according to the embodiments of the present invention. Further, the electronic apparatus  300  includes an optical system (such as a lens)  320  for guiding the incident light to pixel regions of the CMOS image sensor  310  (forming a subject image). The electronic apparatus  300  includes a signal processing circuit (PRC)  330  for processing the output signals from the CMOS image sensor  310 . 
     The signal processing circuit  330  performs predetermined signal processing on the output signals of the CMOS image sensor  310 . The image signals processed in the signal processing circuit  330  can be handled in various manners. For example, the image signals can be displayed as a video image on a monitor having a liquid crystal display, or the image signals can be printed by a printer or recorded directly on a storage medium such as a memory card. 
     As described above, a high-performance, compact, and low-cost camera system can be provided if any of the solid-state imaging devices  10 ,  10 A to  10 C described above is provided as the CMOS image sensor  310 . Further, it is possible to produce electronic apparatuses such as surveillance cameras and medical endoscope cameras that are used for applications where cameras are required to be installed under restricted conditions such as the installation size, number of connectable cables, cable length, and installation height. 
     LIST OF REFERENCE NUMBERS 
     
         
         
           
               10 ,  10 A- 10 C solid-state imaging device 
               20 ,  20 A,  20 B pixel part 
             PD 21 , PD 22  photodiode 
             TG 1 -Tr, TG 2 -Tr transfer transistor 
             RST 1 -Tr, RST 2 -Tr reset transistor 
             SF 1 -Tr, SF 2 -Tr, SF 3 -Tr source follower transistor 
             SEL 1 -Tr, SEL 2 -Tr, SEL 3 -Tr selection transistor 
             FD 21 , FD 22  floating diffusion 
               21  first pixel 
               211  photoelectric conversion reading part 
               212  signal retaining part 
               22  second pixel 
               221  photoelectric conversion reading part 
               30  vertical scanning circuit 
               40 ,  40 C reading circuit (column reading circuit) 
               420  amplifying part 
               430  AD conversion part 
               440  input part 
               50  horizontal scanning circuit 
               60  timing control circuit 
               70  reading part 
               300  electronic apparatus 
               310  CMOS image sensor 
               320  optical system 
               330  signal processing circuit (PRC)