Patent Publication Number: US-2022216249-A1

Title: Image pick-up apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation U.S. patent application Ser. No. 16/924,010 filed on Jul. 8, 2020, which is a continuation U.S. patent application Ser. No. 15/768,378 filed Apr. 13, 2018, now U.S. Pat. No. 10,741,599, which is a national stage application under 35 U.S.C. 371 and claims the benefit of PCT Application No. PCT/JP2016/080220 having an international filing date of Oct. 12, 2016, which designated the United States, which PCT application claimed the benefit of Japanese Priority Patent Application JP 2015-209533 filed on Oct. 26, 2015, the disclosures of each of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present technology relates to an image pick-up apparatus. In detail, the present technology relates to an image pick-up apparatus capable of extending the dynamic range of the image pick-up apparatus. 
     BACKGROUND ART 
     There are technologies to extend the dynamic range of image pick-up apparatuses in various methods. For example, a time-division method in which images are taken with different sensitivities at different times so that the images taken at the different times are synthesized is known. 
     Additionally, for example, a space-division method in which light receiving elements with different sensitivities are provided in an image pick-up apparatus so that synthesizing a plurality of images taken with the light receiving elements, respectively, extends the dynamic range of the image pick-up apparatus is known (for example, see Patent Literature 1 and 2). 
     Furthermore, for example, an in-pixel memory method in which a memory in which the charge overflowing from a photodiode is accumulated is provided on each pixel in an image pick-up apparatus so that the amount of charge accumulated in an exposure period is increased and the increase extends the dynamic range of the image pick-up apparatus (for example, see Patent Literature 3). 
     CITATION LIST 
     Patent Literature 
     
         
         [PTL 1] 
         Japanese Patent No. 3071891 
         [PTL 2] 
         Japanese Patent Application Laid-open No. 2006-253876 
         [PTL 3] 
         Japanese Patent No. 4317115 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     Increasing the number of divided times in the time division method or increasing the number of divided spaces in the space division method can extend the dynamic range of an image pick-up apparatus. On the other hand, however, the increase in number of divided times or divided spaces degrades the quality of images, for example, due to the occurrence of an artifact or the decrease in resolution. 
     Additionally, the limit of the memory capacity limits the extension of the dynamic range in the in-pixel memory method. 
     In light of the foregoing, it is desirable to extend the dynamic range of an image pick-up apparatus without degrading the quality of images. 
     Solution to Problem 
     An image pick-up apparatus according to an aspect of the present technology includes: a pixel array unit, a plurality of unit pixels being arranged in the pixel array unit, the unit pixels including a first opto-electronic converter, and a second opto-electronic converter having a sensitivity lower than a sensitivity of the first opto-electronic converter, the second opto-electronic converter including a light-blocking film formed on a side of the second opto-electronic converter from which light enters the second opto-electronic converter. 
     A lens used to collect light entering the second opto-electronic converter may not be formed on the second opto-electronic converter. 
     A light-blocking wall used to prevent light from leaking from an opto-electronic converter into opto-electronic converters next to the opto-electronic converter may be provided between the opto-electronic converters. 
     The light-blocking film may have a slit. 
     The directions in which slits are formed on light-blocking films formed on the adjacent second opto-electronic converters may be different. 
     The image pick-up apparatus may be a backside-illumination image sensor. 
     The image pick-up apparatus may be a front-side-illumination image sensor. 
     The light-blocking film may be formed on a lower or upper side of a wiring layer formed on the second opto-electronic converter. 
     The light-blocking film may be an amorphous silicon film, a polysilicon film, a Ge film, a GaN film, a CdTe film, a GaAs film, an InP film, a CuInSe2 film, Cu2S, a CIGS film, a non-conductive carbon film, a black resist film, an organic opto-electronic conversion film, or a metal film. 
     In the image pick-up apparatus according to an aspect of the present technology, a unit pixel on a pixel array unit on which a plurality of unit pixels is arranged includes a first opto-electronic converter and a second opto-electronic converter having a sensitivity lower than the sensitivity of the first opto-electronic converter. A light-blocking film is formed on a side of the second opto-electronic converter from which light enters the second opto-electronic converter. 
     Advantageous Effects of Invention 
     According to an aspect of the present technology, the dynamic range of an image pick-up apparatus can be extended without the degradation of the quality of images. 
     According to embodiments of the present disclosure, an imaging device is provided. The imaging device can include a substrate, a first opto-electronic converter having a first area formed in the substrate, and a second opto-electronic converter having a second area formed in the substrate, wherein the first area is larger than the second area. In addition, a trench extends from a first surface of the substrate, such that at least a portion of the trench is between the first opto-electronic converter and the second opto-electronic converter. 
     In accordance with further embodiments of the present disclosure, an imaging device is provided. The imaging device includes a substrate, a first opto-electronic converter, and a second opto-electronic converter. The second opto-electronic converter has a sensitivity that is lower than a sensitivity of the first opto-electronic converter. In addition, a trench extends from a first surface of the substrate such that at least a portion of the trench is between the first opto-electronic converter and the second opto-electronic converter. 
     In accordance with still further embodiments of the present disclosure, an electronic apparatus is provided. The apparatus includes an optical system, an image pick-up element that receives light from the optical system, and a digital signal processor that processes signals received from the imagine pick-up element. The image pick-up element includes a substrate, a first opto-electronic converter having a first area formed in the substrate, and a second opto-electronic converter having a second area formed in the substrate, wherein the first area is larger than the second area. The image pick-up element also includes a light-blocking wall that extends from a first surface of the substrate, wherein at least a portion of the light-blocking wall is between the first opto-electronic converter and the second opto-electronic converter. 
     Note that the effects of the present disclosure are not necessary limited to the effects described above and can be any one of the effects described herein. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic system configuration diagram of a CMOS image sensor using an embodiment of the present technology. 
         FIG. 2  is a circuit diagram of an exemplary configuration of a unit pixel. 
         FIG. 3  is an explanatory timing diagram of the operation when the exposure of a unit pixel starts. 
         FIG. 4  is an explanatory timing diagram of the operation when the unit pixel is read. 
         FIG. 5  is an explanatory diagram of the property of the amount of light and the output describing a signal process. 
         FIG. 6  is an explanatory diagram of a first configuration of a pixel. 
         FIG. 7  is an explanatory diagram of a second configuration of a pixel. 
         FIG. 8  is an explanatory diagram of a third configuration of a pixel. 
         FIG. 9  is an explanatory diagram of a fourth configuration of a pixel. 
         FIG. 10  is an explanatory diagram of a fifth configuration of a pixel. 
         FIG. 11  is an explanatory diagram of a sixth configuration of a pixel. 
         FIG. 12  is an explanatory diagram of a seventh configuration of a pixel. 
         FIG. 13  is an explanatory diagram of an eighth configuration of a pixel. 
         FIG. 14  is an explanatory diagram of a ninth configuration of a pixel. 
         FIG. 15  is an explanatory diagram of a tenth configuration of a pixel. 
         FIG. 16  is an explanatory diagram of an eleventh configuration of a pixel. 
         FIG. 17  is an explanatory diagram of a twelfth configuration of a pixel. 
         FIG. 18  is an explanatory diagram of a thirteenth configuration of a pixel. 
         FIG. 19  is an explanatory diagram of a fourteenth configuration of a pixel. 
         FIG. 20  is an explanatory diagram of a fifteenth configuration of a pixel. 
         FIG. 21  is an explanatory diagram of a sixteenth configuration of a pixel. 
         FIG. 22  is an explanatory diagram of an arrangement of pixels having different sensitivities. 
         FIGS. 23A-B  are an explanatory diagram of an arrangement of colors. 
         FIGS. 24A-C  are an explanatory diagram of an arrangement of light-blocking films. 
         FIG. 25  is a diagram of exemplary uses of the image pick-up apparatus. 
         FIG. 26  is a diagram of a configuration of the image pick-up apparatus. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The modes for carrying out the present technology (hereinafter, referred to as embodiments) will be described hereinafter. Note that the embodiments will be described in the following order. 
     1. Image Pick-up Apparatus Using Present Technology 
     2. Configuration of Unit Pixel (First to Sixteenth Configurations) 
     3. Arrangement of First and Second Opto-electronic Converters 
     4. Exemplary Variations 
     5. Exemplary uses of Image Pick-up Apparatus 
     Image Pick-Up Apparatus Using Present Technology 
       FIG. 1  is a schematic system configuration diagram of a CMOS image sensor that is an image pick-up apparatus using the present technology, for example, a pick-up apparatus using an X-Y address system. In this example, the CMOS image sensor is an image sensor applying or partially using a CMOS process. 
     A CMOS image sensor  10  according to the present exemplary application includes a pixel array unit  11  formed on a semiconductor substrate (chip) (not illustrated), and a peripheral circuit unit integrated with the pixel array unit  11  on the same semiconductor substrate. The peripheral circuit unit includes, for example, a vertical drive unit  12 , a column processing unit  13 , a horizontal drive unit  14 , and a system control unit  15 . 
     The CMOS image sensor  10  further includes a signal processing unit  18 , and a data storage unit  19 . The signal processing unit  18  and the data storage unit  19  can be mounted on the same substrate on which the CMOS image sensor  10  is mounted, or can be placed on a different substrate from the substrate on which the CMOS image sensor  10  is mounted. Additionally, the process that each of the signal processing unit  18  and the data storage unit  19  performs can be processed by an external signal processing unit provided on a different substrate from the substrate on which the CMOS image sensor  10  is mounted, such as a Digital Signal Processor (DSP) circuit or by software. 
     In the pixel array unit  11 , unit pixels (hereinafter, sometimes referred to merely as “pixels”) are arranged in a row direction and a column direction, in other words, two-dimensionally arranged in rows and columns. The unit pixel includes an opto-electronic converter that generates and accumulates the charge corresponding to the amount of light that the opto-electronic converter receives. In this example, the row direction is a direction in which pixels are arranged in a pixel row (namely, a horizontal direction), and the column direction is a direction in which pixels are arranged in a pixel column (namely, a vertical direction). The concrete configuration of the circuit of the unit pixel and the detailed configuration of the unit pixel will be described below. 
     In the pixel array unit  11 , pixel drive lines  16  are distributed to the pixel rows in the row direction, respectively, and vertical signal lines  17  are distributed to pixel columns in the column direction, respectively, in the pixel arrangement in rows and columns. The pixel drive line  16  transmits a drive signal used for the drive to read a signal from a pixel.  FIG. 1  illustrates the pixel drive line  16  as a wire. However, the number of wires is not limited to one. First ends of the pixel drive lines  16  are connected to output terminals of the vertical drive unit  12  that corresponds to the rows, respectively. 
     The vertical drive unit  12  includes a shift register or an address decoder, and drives the pixels in the pixel array unit  11 , for example, simultaneously or row by row. In other words, the vertical drive unit  12  cooperates with a system control unit  15  that controls the vertical drive unit  12  so as to work as a drive unit that controls the operation of each pixel in the pixel array unit  11 . The illustration of the concrete configuration of the vertical drive unit  12  is omitted. However, the vertical drive unit  12  generally includes two scanning systems; a readout scanning system, and a discharge scanning system. 
     The readout scanning system sequentially selects and scans the unit pixels in the pixel array unit  11  row by row so as to read signals from the unit pixels. The signal read from a unit pixel is an analog signal. The discharge scanning system scans a row in discharge scanning the exposure period earlier than the time when the readout scanning system reads and scans the row in readout scanning. 
     The discharge scanning by the discharge scanning system discharges unnecessary charge from the opto-electronic converters of the unit pixels in the read row. This discharge resets the opto-electronic converters. Then, the discharge of the unnecessary charge (the resetting) by the discharge scanning system causes so-called electronic shutter operation. In this example, the electronic shutter operation is the operation in which the charge in the opto-electronic converter is discharged and exposure is newly started (the accumulation of charge is started). 
     The signal read in a readout operation by the readout scanning system corresponds to the amount of light received in and after the readout operation or electronic shutter operation immediately before the readout operation. Then, the period between the readout timing by the readout operation immediately before the current readout operation or the discharge timing by the electronic shutter operation immediately before the current readout operation and the readout timing by the current readout operation is the period of exposure of charge in the unit pixel. 
     A signal is output from each unit pixel in the pixel row selected and scanned by the vertical drive unit  12 . The signal is input via each vertical signal line  17  pixel column by pixel column to the column processing unit  13 . The column processing unit  13  processes the signals output via the vertical signal line  17  from the pixels in the selected row in the pixel array unit  11  pixel column by pixel column in a predetermined signal process, and temporarily stores the pixel signals after the signal process. 
     Specifically, the column processing unit  13  performs at least a noise removal process, for example, a Correlated Double Sampling (CDS) process, or a Double Data Sampling (DDS) process as the signal process. For example, the CDS process removes reset noise or fixed pattern noise specific to a pixel such as the variations in the threshold of the amplification transistor in the pixel. In addition to the noise removal process, the column processing unit  13  can have, for example, an analog-digital (AD) conversion function so that the column processing unit  13  can convert an analog pixel signal into a digital signal and output the digital signal. 
     The horizontal drive unit  14  includes, for example, a shift register and an address decoder so as to sequentially select a unit circuit corresponding to the pixel column of the column processing unit  13 . This selection and scanning by the horizontal drive unit  14  sequentially outputs the pixel signals processed unit circuit by unit circuit in the signal process by the column processing unit  13 . 
     The system control unit  15  includes, for example, a timing generator that generates various timing signals so as to control the drive, for example, of the vertical drive unit  12 , the column processing unit  13 , and the horizontal drive unit  14  on the basis of various times generated by the timing generator. 
     The signal processing unit  18  includes at least an arithmetic process function so as to process the pixel signal output from the column processing unit  13  in various signal processes including the arithmetic process. The data storage unit  19  temporarily stores the data necessary for a signal process so that the signal processing unit  18  performs the signal process. 
     Configuration of Circuit of Unit Pixel  100   
       FIG. 2  is a circuit diagram illustrating the configuration of the unit pixel  100  placed in the pixel array unit  11  in  FIG. 1 . 
     The unit pixel  100  includes a first opto-electronic converter  101 , a first transfer gate unit  102 , a second opto-electronic converter  103 , a second transfer gate unit  104 , a third transfer gate unit  105 , a charge accumulation unit  106 , a reset gate unit  107 , a floating diffusion (FD) unit  108 , an amplification transistor  109 , and a selection transistor  110 . 
     Additionally, the unit pixel  100  is wired with a plurality of drive lines as the pixel drive lines  16  illustrated in  FIG. 1 , for example pixel row by pixel row. Then, various drive signals TGL, TGS, FCG, RST, and SEL are supplied via the drive lines from the vertical drive unit  12  illustrated in  FIG. 1 . These drive signals are a pulse signal that is in an active state at a high level (for example, the power-supply voltage VDD) and is in a non-active state at a low level (for example, negative potential) because each transistor of the unit pixel  100  is an NMOS transistor. 
     The first opto-electronic converter  101  includes, for example, a PN-junction photodiode. The first opto-electronic converter  101  generates and accumulates charge corresponding to the amount of light that the first opto-electronic converter  101  receives. 
     The first transfer gate unit  102  is connected between the first opto-electronic converter  101  and the FD unit  108 . The drive signal TGL is applied to the gate electrode of the first transfer gate unit  102 . When the drive signal TGL is turned into the active state, the first transfer gate unit  102  becomes conductive so that the charge accumulated in the first opto-electronic converter  101  is transferred to the FD unit  108  via the first transfer gate unit  102 . 
     The second opto-electronic converter  103  includes, for example, a PN-junction photodiode, similarly to the first opto-electronic converter  101 . The second opto-electronic converter  103  generates and accumulates the charge corresponding to the amount of light that the second opto-electronic converter  103  receives. 
     In comparison between the first opto-electronic converter  101  and the second opto-electronic converter  103 , the light-receiving surface of the first opto-electronic converter  101  has a larger area and a higher sensitivity than the area and sensitivity of the second opto-electronic converter  103 . As described above, the unit pixel  100  includes two opto-electronic converters having different sensitivities. In other words, the first opto-electronic converter  101  works as a high-sensitivity pixel while the second opto-electronic converter  103  works as a low-sensitivity pixel. 
     The second transfer gate unit  104  is connected between the charge accumulation unit  106  and the FD unit  108 . The drive signal FCG is applied to the gate electrode of the second transfer gate unit  104 . When the drive signal FCG is turned into the active state, the second transfer gate unit  104  becomes conductive so that the potential well of the charge accumulation unit  106  and the potential well of the FD unit  108  are bound or electrically connected to one another. 
     The third transfer gate unit  105  is connected between the second opto-electronic converter  103  and the charge accumulation unit  106 . The drive signal TGS is applied to the gate electrode of the third transfer gate unit  105 . When the drive signal TGS is turned into the active state, the third transfer gate unit  105  becomes conductive so that the charge accumulated in the second opto-electronic converter  103  is transferred via the third transfer gate unit  105  to the charge accumulation unit  106  or a region in which the potential well of the charge accumulation unit  106  and the potential well of the FD unit  108  are bound or electrically connected to one another. 
     Additionally, the potential well is slightly deeper at the lower part of the gate electrode of the third transfer gate unit  105  so as to form an overflow path through which the charge exceeding the amount of charge with which the second opto-electronic converter  103  is saturated and overflowing from the second opto-electronic converter  103  is transferred to the charge accumulation unit  106 . Note that the overflow path formed on the lower part of the gate electrode of the third transfer gate unit  105  is referred to merely as the overflow path of the third transfer gate unit  105 . 
     The charge accumulation unit  106  includes, for example, a capacitor, and is connected between the second transfer gate unit  104  and the third transfer gate unit  105 . The counter electrode of the charge accumulation unit  106  is connected between the charge accumulation unit  106  and the power-supply source VDD that supplies a power-supply voltage VDD. The charge accumulation unit  106  accumulates the charge transferred from the second opto-electronic converter  103 . 
     The reset gate unit  107  is connected between the power-supply source VDD and the FD unit  108 . The drive signal RST is applied to the gate electrode of the reset gate unit  107 . When the drive signal RST is turned into the active state, the reset gate unit  107  becomes conductive so that the potential of the FD unit  108  is reset into the level of the power-supply voltage VDD. 
     The FD unit  108  converts the charge into a voltage signal in charge-voltage conversion and outputs the voltage signal. 
     The gate electrode of the amplification transistor  109  is connected to the FD unit  108  while the drain electrode of the amplification transistor  109  is connected to the power-supply source VDD. The gate electrode and the drain electrode work as an input unit of the readout circuit that reads the charge retained in the FD unit  108 , namely, a so-called source follower circuit. In other words, the source electrode of the amplification transistor  109  is connected via the selection transistor  110  to the vertical signal line  17 , and thus the amplification transistor  109  forms the source follower circuit together with the constant current source  111  connected to a first end of the vertical signal line  17 . 
     The selection transistor  110  is connected between the source electrode of the amplification transistor  109  and the vertical signal line  17 . The selection signal SEL is applied to the gate electrode of the selection transistor  110 . When the selection signal SEL is turned into the active state, the selection transistor  110  is conductive so that the unit pixel  100  is selected. Thus, the pixel signal is output from the amplification transistor  109  via the selection transistor  110  to the vertical signal line  17 . 
     Note that the fact that each drive signal is turned into the active state is referred to also as “each drive signal is turned on” and the fact that each drive signal is turned into the non-active state is referred to also as “each drive signal is turned off”. Additionally, the fact that each gate unit or each transistor becomes conductive is referred to also as “each gate unit or each transistor is turned on” and the fact that each gate unit or each transistor becomes non-conductive is referred to also as “each gate unit or each transistor is turned off”. 
     Operation of Unit Pixel  100   
     Next, the operation of the unit pixel  100  will be described with reference to the timing diagrams of  FIGS. 3 and 4 . First, the operation of the unit pixel  100  at the start of exposure will be described with reference to the timing diagram of  FIG. 3 . This process is performed, for example, by pixel row or by a plurality of pixel rows in the pixel array unit  11  in predetermined scanning order. Note that  FIG. 3  illustrates the timing diagram of the horizontal synchronization signal XHS and the drive signals SEL, RST, TGS, FCG, and TGL. 
     First, the horizontal synchronization signal XHS is input and the process for exposure of the unit pixel  100  is started at a time t 1 . 
     Next, the drive signal RST is turned on and the reset gate unit  107  is turned on at a time t 2 . This resets the potential of the FD unit  108  into the level of the power-supply voltage VDD. 
     Next, the drive signals TGL, FCG, and TGS are turned on and the first transfer gate unit  102 , the second transfer gate unit  104 , and the third transfer gate unit  105  are turned on at a time t 3 . This binds the potential well of the charge accumulation unit  106  with the potential well of the FD unit  108 . Additionally, the charge accumulated in the first opto-electronic converter  101  is transferred via the first transfer gate unit  102  to the bound region in which the potential wells are bound. The charge accumulated in the second opto-electronic converter  103  transferred via the third transfer gate unit  105  to the bound region. Then, the bound region is reset. 
     Next, the drive signals TGL and TGS are turned off and the first transfer gate unit  102  and the third transfer gate unit  105  are turned off at a time t 4 . This starts the accumulation of the charge into the first opto-electronic converter  101  and the second opto-electronic converter  103  and an exposure period starts. 
     Next, the drive signal RST is turned off and the reset gate unit  107  is turned off at a time t 5 . 
     Next, the drive signal FCG is turned off and the second transfer gate unit  104  is turned off at a time t 6 . This causes the charge accumulation unit  106  to start accumulation of the charge overflowing from the second opto-electronic converter  103  and transferred through the overflow path of the third transfer gate unit  105 . 
     Then, the horizontal synchronization signal XHS is input at a time t 7 . 
     (Operation of Unit Pixel  100  for Readout) 
     Next, the operation of the unit pixel  100  for reading a pixel signal will be described with reference to the timing diagram of  FIG. 4 . This process is performed, for example, by pixel row or by a plurality of pixel rows in the pixel array unit  11  in predetermined scanning order after a predetermined period of time has elapsed since the process illustrated  FIG. 3  has been performed. Note that  FIG. 4  illustrates the timing diagram of the horizontal synchronization signal XHS and the drive signals SEL, RST, TGS, FCG, and TGL. 
     First, the horizontal synchronization signal XHS is input and the period of readout of the unit pixel  100  starts at a time t 21 . 
     The selection signal SEL is turned on and the selection transistor  110  is turned on at a time t 22 . Thus, the unit pixel  100  is selected. 
     Next, the drive signal RST is turned on and the reset gate unit  107  is turned on at a time t 23 . Thus, the potential of the FD unit  108  is reset into the level of the power-supply voltage VDD. 
     Next, the drive signal RST is turned off and the reset gate unit  107  is turned off at a time t 24 . 
     Next, the drive signals FCG and TGS are turned on and the second transfer gate unit  104  and the third transfer gate unit  105  are turned on at a time t 25 . This binds the potential well of the charge accumulation unit  106  and the potential well of the FD unit  108  and transfers the charge accumulated in the second opto-electronic converter  103  to the bound region in which the potential wells are bound. Thus, the charge accumulated in the second opto-electronic converter  103  and the charge accumulation unit  106  during the exposure period are accumulated in the bound region. 
     At the time t 25 , the readout of the pixel signal is started and the exposure period is completed. 
     Next, the drive signal TGS is turned off and the third transfer gate unit  105  is turned off at a time t 26 . This stops the transfer of the charge from the second opto-electronic converter  103 . 
     Next, the signal SL based on the potential in the region in which the potential well of the charge accumulation unit  106  and the potential well of the FD unit  108  are bound is output via the amplification transistor  109  and the selection transistor  110  to the vertical signal line  17  at a time to between the time t 26  and the time t 27 . The signal SL is a signal based on the charge generated in the second opto-electronic converter  103  and accumulated in the second opto-electronic converter  103  and the charge accumulation unit  106  during the exposure period. 
     Additionally, the signal SL is a signal based on the potential in the bound region in which the potential well of the charge accumulation unit  106  and the potential well of the FD unit  108  are bound when the charge accumulated in the second opto-electronic converter  103  and the charge accumulation unit  106  during the exposure period is accumulated in the bound region. Thus, the amount of charge converted in charge-voltage conversion when the signal SL is read is the total amount of charge in the charge accumulation unit  106  and the charge of the FD unit  108 . 
     Note that the signal SL is referred to also as a low-sensitivity data signal SL hereinafter. 
     Next, the drive signal RST is turned on and the reset gate unit  107  is turned on at a time t 27 . This resets the region in which the potential well of the charge accumulation unit  106  and the potential well of the FD unit  108  are bound. 
     Next, the selection signal SEL is turned off and the selection transistor  110  is turned off at a time t 28 . Thus, the unit pixel  100  is not selected. 
     Next, the drive signal RST is turned off and the reset gate unit  107  is turned off at a time t 29 . 
     Next, the selection signal SEL is turned on and the selection transistor  110  is turned on at a time t 30 . Thus, the unit pixel  100  is selected. 
     Next, the signal NL based on the potential in the region in which the potential well of the charge accumulation unit  106  and the potential well of the FD unit  108  are bound is output via the amplification transistor  109  and the selection transistor  110  to the vertical signal line  17  at a time tb between the time t 30  and the time t 31 . The signal NL is a signal based on the potential in the bound region in which the potential well of the charge accumulation unit  106  and the potential well of the FD unit  108  are bound when the bound region is reset. 
     Note that the signal NL is referred to also as a low-sensitivity reset signal NL hereinafter. 
     Next, the drive signal FCG is turned off and the second transfer gate unit  104  is turned off at a time t 31 . 
     Next, the signal NH based on the potential of the FD unit  108  is output via the amplification transistor  109  and the selection transistor  110  to the vertical signal line  17  at a time tc between the time t 31  and the time t 32 . The signal NH is a signal based on the potential of the FD unit  108  when the FD unit  108  is reset. 
     Note that the signal NH is referred to also as a high-sensitivity reset signal NH hereinafter. 
     Next, the drive signal TGL is turned on and the first transfer gate unit  102  is turned on at a time t 32 . Thus, the charge generated and accumulated in the first opto-electronic converter  101  during the exposure period is transferred via the first transfer gate unit  102  to the FD unit  108 . 
     Next, the drive signal TGL is turned off and the first transfer gate unit  102  is turned off at a time t 33 . This stops the transfer of the charge from the first opto-electronic converter  101  to the FD unit  108 . 
     Next, the signal SH based on the potential of the FD unit  108  is output via the amplification transistor  109  and the selection transistor  110  to the vertical signal line  17  at a time td between the time t 33  and the time t 34 . The signal SH is a signal based on the charge generated and accumulated in the first opto-electronic converter  101  during the exposure period. 
     Additionally, the signal SH is based on the potential in the FD unit  108  when the charge accumulated in the first opto-electronic converter  101  during the exposure period is accumulated in the FD unit  108 . Thus, the amount of the charge converted in charge-voltage conversion when the signal SH is read is the amount of charge in the FD unit  108 . The amount of charge is smaller than the amount of charge when the low-sensitivity data signal SL is read at the time ta. 
     Note that the signal SH is referred to also as a high-sensitivity data signal SH hereinafter. 
     Next, the selection signal SEL is turned off and the selection transistor  110  is turned off at a time t 34 . Thus, the unit pixel  100  is not selected. 
     Next, the horizontal synchronization signal XHS is input and the readout period in which the pixel signal of the unit pixel  100  is read is completed at a time t 35 . 
     (Description of Noise Removal Process and Arithmetic Process) 
     The low-sensitivity data signal SL, the low-sensitivity reset signal NL, the high-sensitivity reset signal NH, and the high-sensitivity data signal SH are output from the unit pixel  100  to the vertical signal line  17  in this order. Then, in signal processing units placed downstream, for example, the column processing unit  13  and signal processing unit  18  illustrated in  FIG. 1 , the low-sensitivity data signal SL, the low-sensitivity reset signal NL, the high-sensitivity reset signal NH, and the high-sensitivity data signal SH are processed in predetermined noise removal process and signal process. An exemplary noise removal process performed in the column processing unit  13  placed downstream and an exemplary arithmetic process performed in the signal processing unit  18  placed downstream will be described hereinafter. 
     (Noise Removal Process) 
     First, a noise removal process that the column processing unit  13  performs will be described. 
     (Exemplary Noise Removal Process) 
     First, an exemplary noise removal process will be described. 
     The column processing unit  13  generates a low-sensitivity differential signal SNL by taking the difference between the low-sensitivity data signal SL and the low-sensitivity reset signal NL. Thus, the low-sensitivity differential signal SNL=the low-sensitivity data signal SL−the low-sensitivity reset signal NL holds. 
     Next, the column processing unit  13  generates a high-sensitivity differential signal SNH by taking the difference between the high-sensitivity data signal SH and the high-sensitivity reset signal NH. Thus, the high-sensitivity differential signal SNH=the high-sensitivity data signal SH−the high-sensitivity reset signal NH holds. 
     As described above, the low-sensitivity signals SL and NL are processed in a DDS process in which fixed pattern noise specific to a pixel, for example, the variations in the threshold of the amplification transistor in the pixel is removed but reset noise is not removed. The high-sensitivity signals SH and NH is processed in a CDS process in which reset noise and fixed pattern noise specific to a pixel, for example, the variations in the threshold of the amplification transistor in the pixel are removed. 
     (Exemplary Arithmetic Process of Pixel Signal) 
     An exemplary arithmetic process of a pixel signal will be described hereinafter. 
     When the low-sensitivity differential signal SNL is in a predetermined range, the signal processing unit  18  calculates the proportion of the low-sensitivity differential signal SNL to the high-sensitivity differential signal SNH as gain by pixel, by a plurality of pixels, by color, by specific pixel in a shared pixel unit, or evenly in all pixels, and generates a gain table. Then, the signal processing unit  18  calculates the product of the low-sensitivity differential signal SNL and the gain table as the correction value of the low-sensitivity differential signal SNL. 
     In this example, the gain is G and the value of the corrected low-sensitivity differential signal SNL (hereinafter, referred to as a corrected low-sensitivity differential signal) is SNL′. The gain G and the corrected low-sensitivity differential signal SNL′ can be found with the following expressions (1) and (2). 
         G=SNH/SNL =( Cfd+Cfc )/ Cfd   (1)
 
         SNL′=G×SNL   (2)
 
     In this example, Cfd is the value of the capacity of the FD unit  108 , and Cfc is the value of the capacity of the charge accumulation unit  106 . Thus, the gain G is equivalent to the proportion of the capacity of the FD unit  108  to the capacity of the charge accumulation unit  106 . 
       FIG. 5  illustrates the relationship between the amount of incident light and each of the low-sensitivity differential signal SNL, the high-sensitivity differential signal SNH, and the corrected low-sensitivity differential signal SNL′. 
     Next, the signal processing unit  18  uses a predetermined threshold Vt illustrated in  FIG. 5 . In terms of a photo-response characteristic, the threshold Vt is set in a region before the signal processing unit  18  is saturated with the high-sensitivity differential signal SNH and in which the photo-response characteristic is linear. 
     Then, when the high-sensitivity differential signal SNH does not exceed the predetermined threshold Vt, the signal processing unit  18  outputs the high-sensitivity differential signal SNH as the pixel signal SN of the pixel to be processed. In other words, when SNH&lt;Vt holds, the pixel signal SN=the high-sensitivity differential signal SNH holds. 
     On the other hand, when the high-sensitivity differential signal SNH exceeds the predetermined threshold Vt, the signal processing unit  18  outputs the corrected low-sensitivity differential signal SNL′ of the low-sensitivity differential signal SNL as the pixel signal SN of the pixel to be processed. In other words, when Vt&lt;SNH holds, the pixel signal SN=the corrected low-sensitivity differential signal SNL′ holds. 
     By the arithmetic process described above, the signal at a low light condition can smoothly be switched to the signal at a high light condition. 
     Additionally, providing the charge accumulation unit  106  in the low-sensitivity second opto-electronic converter  103  in the CMOS image sensor  10  can raise the level at which the second opto-electronic converter  103  is saturated with the low-sensitivity data signal SL. Thus, while the minimum value of the dynamic range is maintained, the maximum value of the dynamic range can be increased. This can extend the dynamic range. 
     For example, LED flicker sometimes occurs in an in-vehicle image sensor. The LED flicker is a phenomenon in which an image of an object flickering such as an LED light source is not captured depending on the time when the object flickers. The LED flicker occurs, for example, because the dynamic range of an image sensor in the past is narrow and it is necessary to adjust the exposure period for each object. 
     In other words, to deal with objects in various light conditions, an image sensor in the past increases the exposure period for an object in a low light condition and decreases the exposure period for an object in a high light condition. This enables the image sensor in the past to deal with objects in various light conditions even when the dynamic range of the image sensor is narrow. On the other hand, the image sensor reads the signal at a constant rate regardless of the length of the exposure period. Thus, when the exposure period is set at a unit shorter than the period in which the signal is read, the light entering the opto-electronic converter outside the exposure period is converted into charge in opto-electronic conversion and is destroyed without readout. 
     On the other hand, the CMOS image sensor  10  can extend the dynamic range as described above, and can increase the exposure period. This prevents LED flicker from occurring. Additionally, using the CMOS image sensor  10  can prevent an artifact occurring when the number of divided times in a time division scheme or the number of divided spaces in a space division scheme increases, or can prevent the reduction in resolution. 
     Configuration of Unit Pixel 
     Next, the configuration of the unit pixel  100  including the high-sensitivity first opto-electronic converter  101  and the low-sensitivity second opto-electronic converter  103  as described above will additionally be described. Hereinafter, with reference to cross-sectional views of the unit pixel  100 , the configuration of the unit pixel  100  will additionally be described. 
     (First Configuration of Unit Pixel) 
       FIG. 6  is a cross-sectional view of the unit pixel  100  when the CMOS image sensor  10  is a backside-illumination image sensor. The unit pixel  100  illustrated in  FIG. 6  will be referred to as a unit pixel  100 - 1  hereinafter to indicate that the unit pixel  100  illustrated in  FIG. 6  has a first configuration. 
     In the unit pixel  100 - 1 , an on-chip lens  201 , a colored filter  202 , a light-blocking film  203 , and a silicon substrate  204  are layered from the upper part of the drawing. The first opto-electronic converter  101  and the second opto-electronic converter  103  are formed in the silicon substrate  204 . 
     Note that, although not illustrated, for example, a glass cover is layered on the on-chip lens  201 , and a wiring layer or a supporting substrate is layered under the silicon substrate  204 . The parts necessary for the description will be properly illustrated and described while the illustration and description of the other parts will properly be omitted hereinafter. 
       FIG. 6  illustrates the first opto-electronic converter  101 - 1 , the first opto-electronic converter  101 - 2 , and the second opto-electronic converter  103 . Additionally, the on-chip lenses  201 - 1  to  201 - 3  are formed on the three opto-electronic converters, respectively. 
     The light-blocking film  203  is formed only on the second opto-electronic converter  103 . The light-blocking film  203  has a function to absorb or reflect light. The light-blocking film  203  can be made of a metal film so that the light-blocking film  203  works as a film that reflects light. The light-blocking film  203  can be a film that absorbs a part of light and allows a part of the light to pass through the film. Alternatively, the light-blocking film  203  can be an optical absorption film that absorbs light. 
     The light-blocking film  203  is, for example, an amorphous silicon film, a polysilicon film, a germanium (Ge) film, a gallium nitride (GaN) film, a cadmium telluride (CdTe) film, a gallium arsenide (GaAs) film, an indium phosphide (InP) film, a CuInSe2 film, a Cu2S film, a CIGS film, a non-conductive carbon film, a black resist film, or an organic opto-electronic conversion film. 
     Note that the light-blocking film is formed on the second opto-electronic converter  103  and the light-blocking film can be made of the materials described above also in second to sixteenth configurations described below. Note that the materials of which the light-blocking film is made are examples. The material of which the light-blocking film is made is not limited to the example materials. 
     Forming the light-blocking film  203  on the low-sensitivity second opto-electronic converter  103  as described above causes the light-blocking film  203  to absorb the light passing through the on-chip lens  201 - 3  and reduces the light entering the second opto-electronic converter  103 . This further reduces the sensitivity of the second opto-electronic converter  103 . This increases the performance of the second opto-electronic converter  103  as the low-sensitivity opto-electronic converter. Thus, the dynamic range can be extended. 
     (Second Configuration of Unit Pixel) 
     Next, the second configuration of the unit pixel  100  will be described.  FIG. 7  is a cross-sectional view of a unit pixel  100 - 2  when the CMOS image sensor  10  is a backside-illumination image sensor, similarly to the unit pixel  100 - 1  illustrated in  FIG. 6 . 
     In comparison between the unit pixel  100 - 2  illustrated in  FIG. 7  and the unit pixel  100 - 1  illustrated in  FIG. 6 , the unit pixel  100 - 2  has a configuration in which the on-chip lens  201 - 3  formed on the second opto-electronic converter  103  in the unit pixel  100 - 1  is removed, differently from the unit pixel  100 - 1 , and the other parts in the unit pixel  100 - 2  are the same as the parts in the unit pixel  100 - 1 . Hereinafter, the description of the parts similar to the parts of the unit pixel  100 - 1  will be put with similar reference signs and the descriptions will properly be omitted. Similarly, the descriptions of the other parts will properly be omitted when the other parts are similar to the parts of the unit pixel  100 - 1 . 
     The unit pixel  100 - 2  has a configuration in which the on-chip lens  201 - 3  is not formed on the second opto-electronic converter  103 . Thus, the light is not collected on the second opto-electronic converter  103  and enters the second opto-electronic converter  103  and the light entering the second opto-electronic converter  103  is reduced. This further reduces the sensitivity of the second opto-electronic converter  103  and can extend the dynamic range of the low-sensitivity opto-electronic converter. 
     (Third Configuration of Unit Pixel) 
     Next, the third configuration of the unit pixel  100  will be described.  FIG. 8  is a cross-sectional view of a unit pixel  100 - 3  when the CMOS image sensor  10  is a backside-illumination image sensor, similarly to the unit pixel  100 - 1  illustrated in  FIG. 6 . 
     In comparison between the unit pixel  100 - 3  illustrated in  FIG. 8  and the unit pixel  100 - 1  illustrated in  FIG. 6 , the unit pixel  100 - 3  has a configuration in which a light-blocking wall  231  is added to the configuration of the unit pixel  100 - 1 , differently from the unit pixel  100 - 1 , and the other parts of the unit pixel  100 - 3  are the same as the parts of the unit pixel  100 - 1 . 
     The light-blocking wall  231  is provided between pixels. In the unit pixel  100 - 3  illustrated in  FIG. 8 , the light-blocking walls  231  are provided between the first opto-electronic converter  101 - 1  and the second opto-electronic converter  103 , and between the first opto-electronic converter  101 - 2  and the second opto-electronic converter  103 . As describe above, the light-blocking wall  231  is provided in a pixel separation region in which the pixels are separate from each other. The light-blocking wall  231  can be formed in a trench or groove and can include one or more insulating films extending from the light receiving surface. 
     The light-blocking walls  231  can be formed in trenches from a combination of a negative fixed charge film and an oxide film. The combination can be a combination of a negative fixed charge film, an oxide film, and a metal. Examples of a negative fixed charge film include hafnium oxide and tantalum oxide. 
     The light-blocking wall  231  is used to prevent light leaking from an opto-electronic converter into the opto-electronic converters next to the opto-electronic converter. Providing the light-blocking wall  231  can reduce, for example, the occurrence of mixture of colors. In addition, the light-blocking wall  231  can prevent light from leaking into a low sensitivity pixel  103  from other pixels, and can therefore_help to maintain the accuracy of the unit pixel output. 
     Also in this configuration, forming a light-blocking film  203  on the low-sensitivity second opto-electronic converter  103  causes the light-blocking film  203  to absorb the light passing through the on-chip lens  201 - 3  and reduces the light entering the second opto-electronic converter  103 . This further reduces the sensitivity of the second opto-electronic converter  103 . Thus, the dynamic range can be extended. Providing the light-blocking wall  231  can reduce, for example, the occurrence of mixture of colors. 
     (Fourth Configuration of Unit Pixel) 
     Next, the fourth configuration of the unit pixel  100  will be described.  FIG. 9  is a cross-sectional view of a unit pixel  100 - 4  when the CMOS image sensor  10  is a backside-illumination image sensor, similarly to the unit pixel  100 - 2  illustrated in  FIG. 7 . 
     In comparison between the unit pixel  100 - 4  illustrated in  FIG. 9  and the unit pixel  100 - 2  illustrated in  FIG. 7 , the unit pixel  100 - 4  has a configuration in which a light-blocking wall  231  is added to the configuration of the unit pixel  100 - 2 , differently from the unit pixel  100 - 2 , and the other parts, for example, the second opto-electronic converter  103  without the on-chip lens  201 - 3  in the unit pixel  100 - 4  are the same as the parts of the unit pixel  100 - 2 . Additionally, the configuration to which the light-blocking wall  231  is added is the same as the configuration of the unit pixel  100 - 3  illustrated in  FIG. 8 . 
     Also in this configuration, forming a light-blocking film  203  on the low-sensitivity second opto-electronic converter  103  causes the light-blocking film  203  to absorb the light entering the light-blocking film  203  and reduces the light entering the second opto-electronic converter  103 . Additionally, an on-chip lens is not formed. This further reduces the amount of light entering the second opto-electronic converter  103 . This further reduces the sensitivity of the second opto-electronic converter  103 . Thus, the dynamic range of the low-sensitivity opto-electronic converter can be extended. Providing the light-blocking wall  231  can reduce, for example, the occurrence of mixture of colors. 
     (Fifth Configuration of Unit Pixel) 
     Next, the fifth configuration of the unit pixel  100  will be described.  FIG. 10  is a cross-sectional view of a unit pixel  100 - 5  when the CMOS image sensor  10  is a backside-illumination image sensor, similarly to the unit pixel  100 - 1  illustrated in  FIG. 6 . 
     In comparison between the unit pixel  100 - 5  illustrated in  FIG. 10  and the unit pixel  100 - 1  illustrated in  FIG. 6 , the unit pixel  100 - 5  has a configuration in which a light-blocking film  251  of the unit pixel  100 - 5  has a different shape from the light-blocking film  203  of the unit pixel  100 - 1 , differently from the unit pixel  100 - 1 , and the other parts are the same as the parts of the unit pixel  100 - 1 . The light-blocking film  251  of the unit pixel  100 - 5  has a slit. The light-blocking film  251  is not necessarily formed on the slit of the light-blocking film  251 . Alternatively, the light-blocking film  251  at the slit can be thinner than light-blocking film  251  at parts other than the slit. 
     Forming a slit on the light-blocking film  251  can cause the second opto-electronic converter  103  to work as a polarization pixel. 
     For example, when the second opto-electronic converter  103  is installed on a vehicle and captures an image including the surface of a road, the light reflected on the surface of the road is a polarized light in parallel to the surface of the road. To capture an image from which such a polarized light is removed, a slit is formed on the light-blocking film  251  in a direction parallel to the surface of the road. This can selectively block the light reflected on the surface of the road and can receive the light from the other objects. 
     Forming a slit on the light-blocking film  251  as described above can reduce the light entering the second opto-electronic converter  103  and also can remove unnecessary light. 
     When the light-blocking film  251  is used also as a polarizer as described above, the light-blocking film  251  can be made of metal in addition to the materials described above. Note that using the light-blocking film as the polarizer can effectively reduce the direct or indirect light in comparison with using a polarizer made of metal. 
     Also in this configuration, forming the light-blocking film  251  on the low-sensitivity second opto-electronic converter  103  reduces the amount of light entering the second opto-electronic converter  103 . Thus, lowering the sensitivity can extend the dynamic range. Additionally, forming a slit on the light-blocking film  251  can cause the light-blocking film  251  to work as a polarizer so as to remove the effect of unnecessary light such as the reflected light. 
     (Sixth Configuration of Unit Pixel) 
     Next, the sixth configuration of the unit pixel  100  will be described.  FIG. 11  is a cross-sectional view of a unit pixel  100 - 6  when the CMOS image sensor  10  is a backside-illumination image sensor, similarly to the unit pixel  100 - 2  illustrated in  FIG. 7 . 
     In comparison between the unit pixel  100 - 6  illustrated in  FIG. 11  and the unit pixel  100 - 2  illustrated in  FIG. 7 , the unit pixel  100 - 6  has a configuration in which the light-blocking film  251  of the unit pixel  100 - 6  has a different shape from the light-blocking film  203  of the unit pixel  100 - 2 , differently from the unit pixel  100 - 2 , and the other parts, for example, the second opto-electronic converter  103  without the on-chip lens  201 - 3  in the unit pixel  100 - 6  are the same as the parts of the unit pixel  100 - 2 . The light-blocking film  251  of the unit pixel  100 - 6  has a slit, similarly to the unit pixel  100 - 5  illustrated in  FIG. 10 . 
     Forming a slit on the light-blocking film  251  can reduce the light entering the second opto-electronic converter  103  and also can remove unnecessary light, similarly to the unit pixel  100 - 5  ( FIG. 10 ). 
     Also in this configuration, forming the light-blocking film  251  on the low-sensitivity second opto-electronic converter  103  reduces the amount of light entering the second opto-electronic converter  103 . Thus, lowering the sensitivity can extend the dynamic range. Additionally, an on-chip lens is not formed on the second opto-electronic converter  103 . This further reduces the amount of light entering the second opto-electronic converter  103 . Thus, lowering the sensitivity can extend the dynamic range. Additionally, forming a slit on the light-blocking film  251  can cause the light-blocking film  251  to work as a polarizer so as to remove the effect of unnecessary light such as the reflected light. 
     (Seventh Configuration of Unit Pixel) 
     Next, the seventh configuration of the unit pixel  100  will be described.  FIG. 12  is a cross-sectional view of a unit pixel  100 - 7  when the CMOS image sensor  10  is a backside-illumination image sensor, similarly to the unit pixel  100 - 3  illustrated in  FIG. 8 . 
     In comparison between the unit pixel  100 - 7  illustrated in  FIG. 12  and the unit pixel  100 - 3  illustrated in  FIG. 8 , the unit pixel  100 - 7  has a configuration in which the light-blocking film  251  has a slit, differently from the unit pixel  100 - 3 , and the other parts, for example, the light-blocking film  231  provided between pixels in the unit pixel  100 - 7  are the same as the parts of the unit pixel  100 - 3 . 
     Also in this configuration, forming the light-blocking film  251  on the low-sensitivity second opto-electronic converter  103  reduces the light entering the second opto-electronic converter  103 . Thus, lowering the sensitivity can extend the dynamic range. Additionally, forming a slit on the light-blocking film  251  can cause the light-blocking film  251  to work as a polarizer so as to remove the effect of unnecessary light such as the reflected light. Providing the light-blocking wall  231  can reduce, for example, the occurrence of mixture of colors. 
     (Eighth Configuration of Unit Pixel) 
     Next, the eighth configuration of the unit pixel  100  will be described.  FIG. 13  is a cross-sectional view of a unit pixel  100 - 8  when the CMOS image sensor  10  is a backside-illumination image sensor, similarly to the unit pixel  100 - 4  illustrated in  FIG. 9 . 
     In comparison between the unit pixel  100 - 8  illustrated in  FIG. 13  and the unit pixel  100 - 4  illustrated in  FIG. 9 , the unit pixel  100 - 8  has a configuration in which the light-blocking film  251  has a slit, differently from the unit pixel  100 - 4 , and the other parts, for example, the light-blocking film  231  provided between pixels in the unit pixel  100 - 8  and the second opto-electronic converter  103  without an on-chip lens are the same as the parts of the unit pixel  100 - 4 . 
     Also in this configuration, forming the light-blocking film  251  on the low-sensitivity second opto-electronic converter  103  reduces the light entering the second opto-electronic converter  103 . Thus, lowering the sensitivity can extend the dynamic range. Additionally, an on-chip lens is not formed on the second opto-electronic converter  103 . This further reduces the light entering the second opto-electronic converter  103 . Thus, lowering the sensitivity can extend the dynamic range. 
     Additionally, forming a slit on the light-blocking film  251  can cause the light-blocking film  251  to work as a polarizer so as to remove the effect of unnecessary light such as the reflected light. Providing the light-blocking wall  231  can reduce, for example, the occurrence of mixture of colors. 
     (Ninth Configuration of Unit Pixel) 
       FIG. 14  is a cross-sectional view of a unit pixel  100 - 9  when the CMOS image sensor  10  is a front-side-illumination image sensor. 
     In the unit pixel  100 - 9  illustrated in  FIG. 14 , an on-chip lens  301 , a colored filter  302 , a light-blocking film  303 , a wiring layer  304 , and a silicon substrate  305  are layered from the upper part of the drawing. A first opto-electronic converter  101  and a second opto-electronic converter  103  are formed in the silicon substrate  305 . 
     Note that, although not illustrated in the drawing, for example, a glass cover is layered on the on-chip lens  201 . The parts necessary for the description will properly be illustrated and additionally described while the illustration and description of the other parts will properly be omitted. 
       FIG. 14  illustrates the first opto-electronic converter  101 - 1 , the first opto-electronic converter  101 - 2 , and the second opto-electronic converter  103 . Additionally, on-chip lenses  301 - 1  to  301 - 3  are formed on the three opto-electronic converters, respectively. 
     The light-blocking film  303  is formed only on the second opto-electronic converter  103 . The light-blocking film  303  is, for example, an amorphous silicon film, a polysilicon film, a Ge film, a GaN film, a CdTe film, a GaAs film, an InP film, a CuInSe2 film, Cu2S, a CIGS film, a non-conductive carbon film, a black resist film, or an organic opto-electronic conversion film. Additionally, when the light-blocking film  303  has a slit as described below, the light-blocking film  303  can be made of metal. Note that the materials of which the light-blocking film is made are examples and the material of which the light-blocking film is made is not limited to the example materials. 
     Also in the front-side illumination image sensor as described above, forming the light-blocking film  303  on the low-sensitivity second opto-electronic converter  103  causes the light-blocking film  303  to absorb the light passing through the on-chip lens  301 - 3  and reduces the light entering the second opto-electronic converter  103 . This further reduces the sensitivity of the second opto-electronic converter  103 . Thus, the dynamic range can be extended. 
     (Tenth Configuration of Unit Pixel) 
     Next, the tenth configuration of the unit pixel  100  will be described.  FIG. 15  is a cross-sectional view of a unit pixel  100 - 10  when the CMOS image sensor  10  is a front-side-illumination image sensor, similarly to the unit pixel  100 - 9  illustrated in  FIG. 14 . 
     In comparison between the unit pixel  100 - 10  illustrated in  FIG. 15  and the unit pixel  100 - 9  illustrated in  FIG. 14 , the unit pixel  100 - 10  has a configuration in which the on-chip lens  301 - 3  formed on the second opto-electronic converter  103  in the unit pixel  100 - 9  is removed, differently from the unit pixel  100 - 9 , and the other parts in the unit pixel  100 - 10  are the same as the parts in the unit pixel  100 - 9 . 
     The on-chip lens  301 - 3  is not formed on the second opto-electronic converter  103 . This causes the light to enter the second opto-electronic converter  103  without being collected. This reduces the light entering the second opto-electronic converter  103 . Thus, lowering the sensitivity of the second opto-electronic converter  103  can extend the dynamic range. 
     (Eleventh Configuration of Unit Pixel) 
     Next, the eleventh configuration of the unit pixel  100  will be described.  FIG. 16  is a cross-sectional view of a unit pixel  100 - 11  when the CMOS image sensor  10  is a front-side-illumination image sensor, similarly to the unit pixel  100 - 9  illustrated in  FIG. 14 . 
     In comparison between the unit pixel  100 - 11  illustrated in  FIG. 16  and the unit pixel  100 - 9  illustrated in  FIG. 14 , the light-blocking film  303  is formed on the upper side of the wiring layer  304  (the side facing the on-chip  301 ) in the drawing in the unit pixel  100 - 9  while the light-blocking film is formed on the lower side of the wiring layer  304  (the side facing the silicon substrate  305 ) in the drawing in the unit pixel  100 - 11 . The other parts in the unit pixel  100 - 11  are the same as the parts in the unit pixel  100 - 9 . 
     With reference to  FIG. 14  again, the light-blocking film  303  of the unit pixel  100 - 9  is formed on the upper side of the wiring layer  304  and in the colored filter  302 . On the other hand, the light-blocking film  331  of the unit pixel  100 - 11  illustrated in  FIG. 15  is formed on the lower side of the wiring layer  304  and in the wiring layer  304  on the silicon substrate  305 . As described above, the light-blocking film can be formed on the upper or lower side of the wiring layer  304 . 
     As described above, also in a front-side illumination image sensor, the light-blocking film  303  is formed on the low-sensitivity second opto-electronic converter  103 . This causes the light-blocking film  303  to absorb the light passing through the on-chip lens  301 - 3  and reduces the light entering the second opto-electronic converter  103 . This further reduces the sensitivity of the second opto-electronic converter  103 . Thus, the dynamic range can be extended. 
     (Twelfth Configuration of Unit Pixel) 
     Next, the twelfth configuration of the unit pixel  100  will be described.  FIG. 17  is a cross-sectional view of a unit pixel  100 - 12  when the CMOS image sensor  10  is a front-side-illumination image sensor, similarly to the unit pixel  100 - 11  illustrated in  FIG. 16 . 
     In comparison between the unit pixel  100 - 12  illustrated in  FIG. 17  and the unit pixel  100 - 11  illustrated in  FIG. 16 , the unit pixel  100 - 12  has a configuration in which the on-chip lens  301 - 3  formed on the second opto-electronic converter  103  in the unit pixel  100 - 11  is removed, differently from the unit pixel  100 - 11  and the other parts in the unit pixel  100 - 12  are the same as the parts in the unit pixel  100 - 11 . 
     The on-chip lens  301 - 3  is not formed on the second opto-electronic converter  103 . Thus, light is not collected on the second opto-electronic converter  103  and enters the second opto-electronic converter  103 . This reduces the light entering the second opto-electronic converter  103 . Thus lowering the sensitivity of the second opto-electronic converter  103  and extending the dynamic range. 
     (Thirteenth Configuration of Unit Pixel) 
     Next, the thirteenth configuration of the unit pixel  100  will be described.  FIG. 18  is a cross-sectional view of a unit pixel  100 - 13  when the CMOS image sensor  10  is a front-side-illumination image sensor, similarly to the unit pixel  100 - 9  illustrated in  FIG. 14 . 
     In comparison between the unit pixel  100 - 13  illustrated in  FIG. 18  and the unit pixel  100 - 9  illustrated in  FIG. 14 , the unit pixel  100 - 13  has a configuration in which the light-blocking film  351  of the unit pixel  100 - 13  has a different shape from the light-blocking film  303  of the unit pixel  100 - 9 , differently from the unit pixel  100 - 9 , and the other parts of the unit pixel  100 - 13  are the same as the parts of the unit pixel  100 - 9 . The light-blocking film  351  of the unit pixel  100 - 13  has a slit shape and formed in the layer of the colored filter  302 . 
     Forming a slit on the light-blocking film  351  can cause the light-blocking film  351  to work as a polarizer and the second opto-electronic converter  103  to a polarization pixel. 
     Also in this configuration, forming the light-blocking film  351  on the low-sensitivity second opto-electronic converter  103  reduces the light entering the second opto-electronic converter  103 . Thus lowering the sensitivity, which can extend the dynamic range. Additionally, forming a slit on the light-blocking film  351  can cause the light-blocking film  351  to work as a polarizer so as to remove the effect of unnecessary light such as the reflected light. 
     (Fourteenth Configuration of Unit Pixel) 
     Next, the fourteenth configuration of the unit pixel  100  will be described.  FIG. 19  is a cross-sectional view of a unit pixel  100 - 14  when the CMOS image sensor  10  is a front-side-illumination image sensor, similarly to the unit pixel  100 - 13  illustrated in  FIG. 18 . 
     In comparison between the unit pixel  100 - 14  illustrated in  FIG. 19  and the unit pixel  100 - 13  illustrated in  FIG. 18 , the unit pixel  100 - 14  has a configuration in which the on-chip lens  301 - 3  formed on the second opto-electronic converter  103  in the unit pixel  100 - 13  is removed, differently from the unit pixel  100 - 13  and the other parts in the unit pixel  100 - 14  are the same as the parts in the unit pixel  100 - 13 . The light-blocking film  351  of the unit pixel  100 - 14  has a slit, and formed in the layer of the colored filter  302 . 
     The on-chip lens  301 - 3  is not formed on the second opto-electronic converter  103 . Thus, light is not collected on the second opto-electronic converter  103  and enters the second opto-electronic converter  103 . This reduces the light entering the second opto-electronic converter  103 . This further reduces the sensitivity of the second opto-electronic converter  103 . Thus, the dynamic range can be extended. Additionally, forming a slit on the light-blocking film  351  can cause the light-blocking film  351  to work as a polarizer so as to remove the effect of unnecessary light such as the reflected light. 
     (Fifteenth Configuration of Unit Pixel) 
     Next, the fifteenth configuration of the unit pixel  100  will be described.  FIG. 20  is a cross-sectional view of a unit pixel  100 - 15  when the CMOS image sensor  10  is a front-side-illumination image sensor, similarly to the unit pixel  100 - 13  illustrated in  FIG. 18 . 
     In comparison between the unit pixel  100 - 15  illustrated in  FIG. 20  and the unit pixel  100 - 13  illustrated in  FIG. 18 , the light-blocking film  351  is formed on the upper side of the wiring layer  304  in the drawing in the unit pixel  100 - 13  while the light-blocking film  381  is formed on the lower side of the wiring layer  304  in the drawing in the unit pixel  100 - 15 . The other parts in the unit pixel  100 - 15  are the same as the parts in the unit pixel  100 - 13 . In other words, the light-blocking film  381  of the unit pixel  100 - 15  has a slit, and is formed on the lower side of the wiring layer  304  in the drawing in the unit pixel  100 - 15 . 
     Also in the front-side illumination image sensor having this configuration, forming the light-blocking film  381  on the low-sensitivity second opto-electronic converter  103  causes the light-blocking film  381  to absorb the light passing through the on-chip lens  301 - 3  and reduces the light entering the second opto-electronic converter  103 . Thus lowering the sensitivity of the second opto-electronic converter  103 , which can extend the dynamic range. Additionally, forming a slit on the light-blocking film  381  can cause the light-blocking film  351  to work as a polarizer so as to remove the effect of unnecessary light such as the reflected light. 
     (Sixteenth Configuration of Unit Pixel) 
     Next, the sixteenth configuration in the unit pixel  100  will be described.  FIG. 21  is a cross-sectional view of a unit pixel  100 - 16  when the CMOS image sensor  10  is a front-side-illumination image sensor, similarly to the unit pixel  100 - 15  illustrated in  FIG. 20 . 
     In comparison between the unit pixel  100 - 16  illustrated in  FIG. 21  and the unit pixel  100 - 15  illustrated in  FIG. 20 , the unit pixel  100 - 16  has a configuration in which the on-chip lens  301 - 3  formed on the second opto-electronic converter  103  in the unit pixel  100 - 15  is removed, differently from the unit pixel  100 - 15  and the other parts in the unit pixel  100 - 16  are the same as the parts in the unit pixel  100 - 15 . In other words, the light-blocking film  381  of the unit pixel  100 - 16  has a slit and is formed on the lower side of the wiring layer  304 . 
     The on-chip lens  301 - 3  is not formed on the second opto-electronic converter  103 . Thus, light is not collected on the second opto-electronic converter  103  and enters the second opto-electronic converter  103 . This reduces the light entering the second opto-electronic converter  103 . Thus lowering the sensitivity of the second opto-electronic converter  103 , which can extend the dynamic range. Additionally, forming a slit on the light-blocking film  381  can cause the light-blocking film  381  to work as a polarizer so as to remove the effect of unnecessary light such as the reflected light. 
     As described in the first to sixteenth configurations, a film having a function to absorb light is formed on the low-sensitivity second opto-electronic converter  103 . This reduces the amount of light entering the second opto-electronic converter  103 . Thus, lowering the sensitivity can extend the dynamic range. 
     Additionally, forming a slit on the light-blocking film can cause the light-blocking film to work as a polarizer. Providing the polarizer removes the effect of the reflected light (the effect of unnecessary light) and simultaneously, lowering the sensitivity, which can extend the dynamic range. 
     Using the light-blocking film as the polarizer can effectively reduce the direct or indirect light in comparison with using a polarizer made of metal. 
     Arrangement of First and Second Opto-Electronic Converters 
     The unit pixels  100 , each of which includes a first opto-electronic converter  101  and a second opto-electronic converter  103 , are arranged, for example, as illustrated in  FIG. 22 . In  FIG. 22 , the unit pixels are referred to as unit pixels  500 . A unit pixel  500  will be described as one of the unit pixels  100 - 1  to  100 - 18 . 
       FIG. 22  illustrates an example in which (four by four) 16 unit pixels  500 - 1  to  500 - 16  are arranged. Each unit pixel  500  includes a first opto-electronic converter  101  and a second opto-electronic converter  103 . For example, the unit pixel  500 - 1  includes a first opto-electronic converter  101 - 1  and a second opto-electronic converter  103 - 1 . 
     The first opto-electronic converter  101  and the second opto-electronic converter  103  have different sensitivities depending on the size of the light-receiving surface. In other words, as illustrated in  FIG. 22 , the light-receiving surface of the first opto-electronic converter  101  is larger than the light-receiving surface of the second opto-electronic converter  103 . 
     In the example of  FIG. 22 , for example, the second opto-electronic converter  103 - 1  of a unit pixel is placed on the right and obliquely lower side of the first opto-electronic converter  101 - 1  of that unit pixel. Although not illustrated, the second opto-electronic converter  103 - 1  can be placed on the right side of the first opto-electronic converter  101 - 1 . Alternatively, the positional relationship between the second opto-electronic converter  103 - 1  and the first opto-electronic converter  101 - 1  can be different from the above. For example, at least a portion of a side of the second opto-electronic converter  103 - 1  can coincide with or can be adjacent to a portion of a side of the first opto-electronic converter  101 - 1 . 
     In the unit pixel  500 , for example, a signal process circuit can be placed at a part at which the first opto-electronic converter  101  and the second opto-electronic converter  103  are not arranged. In other words, arranging the first opto-electronic converter  101  and second opto-electronic converter  103  with different light-receiving areas causes an excessive region in the unit pixel  500 . However, placing, for example, a signal process circuit in the excessive region can effectively use the excessive region. 
     The colors of the colored filters  202  ( 302 ) placed on the unit pixels  500  can be arranged, for example, in Bayer arrangement. As illustrated in  FIG. 23A , the unit pixel  500 - 1  can be red (R), the unit pixel  500 - 2  can be green (G), the unit pixel  500 - 5  can be green (G), and the unit pixel  500 - 6  can be blue (B). 
     In the color arrangement described above, with reference to  FIGS. 22 and 23A  again, for example, the first opto-electronic converter  101 - 1  and the second opto-electronic converter  103 - 1  are arranged and the color of the colored filter  202  (or  302 , hereinafter, the colored filter  202  is cited as an example for the description) is red (R) in the unit pixel  500 - 1 . As described above, the first opto-electronic converter  101  and second opto-electronic converter  103  arranged in the same unit pixel  500  have the color of the same colored filter  202 . 
     As illustrated in  FIG. 23B , the colors can be arranged in Bayer arrangement in which four pixels have the same color. In  FIG. 23B , the unit pixel  500 - 1 , the unit pixel  500 - 2 , the unit pixel  500 - 5 , and the unit pixel  500 - 6  are red (R); the unit pixel  500 - 3 , the unit pixel  500 - 4 , the unit pixel  500 - 7 , and the unit pixel  500 - 8  are green (G); the unit pixel  500 - 9 , the unit pixel  500 - 10 , the unit pixel  500 - 13 , and the unit pixel  500 - 14  are green (G); and the unit pixel  500 - 11 , the unit pixel  500 - 12 , the unit pixel  500 - 15 , and the unit pixel  500 - 16  are green (G). 
     In this example, Bayer arrangement is cited as an example of the color arrangement. However, the present technology can be used for another color arrangement. 
     A light-blocking film is formed on the second opto-electronic converter  103  as described above. The light-blocking film is the light-blocking film  203  without a slit illustrated, for example, in  FIG. 6  (hereinafter, referred to as a solid light-blocking film  203 ), or the light-blocking film  251  with a slit illustrated, for example, in  FIG. 10 . 
     Note that, although the light-blocking film  203  ( FIG. 6 ) will be cited as an example of the solid light-blocking film for the description hereinafter, the description can be applied to the light-blocking film  303  ( FIG. 14 ) and the light-blocking film  331  ( FIG. 16 ). Additionally, the light-blocking film  251  ( FIG. 10 ) will be cited as an example of the slit light-blocking film for the description hereinafter. However, the description can be applied to the light-blocking film  351  ( FIG. 18 ) and the light-blocking film  381  ( FIG. 20 ). 
     When the solid light-blocking films  203  are formed on the unit pixel, the light-blocking film  203  are formed, for example, as illustrated in  FIG. 24A .  FIG. 24A  only illustrates left and upper four pixels among the (four by four) 16 unit pixels  500 - 1  to  500 - 16  illustrated in  FIG. 22 . However, the light-blocking films  203  are similarly formed on the other pixels. 
     As illustrated in  FIG. 24A , the solid light-blocking films  203  are formed on the second opto-electronic converters  103  in the unit pixels  500 . For example, the second opto-electronic converter  103  is formed on the right and lower side of the unit pixel  500 - 1  illustrated in  FIG. 24A , and a light-blocking film  203 - 1  is formed in the region in which the second opto-electronic converter  103 - 1  is formed. 
     Note that, as illustrated in  FIG. 24A , the light-blocking film  203  can be formed so that the light-blocking film  203  is connected to a well (WELL) in an outer peripheral region of the pixel. 
     When the slit light-blocking films  251  are formed on the unit pixels, the light-blocking film  251  are formed, for example, as illustrated in  FIG. 24B . As illustrated in  FIG. 24B , the slit light-blocking films  251  are formed on the second opto-electronic converters  103  in the unit pixels  500 , respectively. 
     The slits illustrated in  FIG. 24B  extend in the lateral direction of the drawing and all the four pixels have slits extending in the same direction. As described above, the slits on the light-blocking films  251  provided on the second opto-electronic converters  103  can be formed in the same direction. 
     The direction in which the slits are arranged on the light-blocking films  251  can be varied depending on the pixel.  FIG. 24C  illustrates that the light-blocking films  251  are formed on the second opto-electronic converters  103  in the unit pixels  500 , respectively, and the slits of the light-blocking films  251  with slits are formed in different directions depending on the pixel. 
     The slits on the light-blocking film  251 - 1  formed on the second opto-electronic converter  103 - 1  in the unit pixel  500 - 1  illustrated in  FIG. 24C  are formed in the lateral direction of the drawing. The slits on the light-blocking film  251 - 2  formed on the second opto-electronic converter  103 - 2  in the unit pixel  500 - 2  are formed in a direction toward the left and obliquely toward the lower side of the drawing. 
     The slits on the light-blocking film  251 - 5  formed on the second opto-electronic converter  103 - 5  in the unit pixel  500 - 5  are formed in a direction toward the right and obliquely toward the lower side of the drawing. The slits on the light-blocking film  251 - 6  formed on the second opto-electronic converter  103 - 6  in the unit pixel  500 - 6  are formed in the longitudinal direction of the drawing. 
     In the example illustrated in  FIG. 24C , the slits are formed in the four directions. Similarly, in the other pixels (not illustrated), the slits are formed on the light-blocking films  251  so that the slits are formed in four different directions in (two by two) four pixels depending on the pixel. Note that, although the four directions are cited as an example in this example, another direction can be added or, for example, the slits can be formed in two or three directions. The number of directions in which the slits are formed on the light-blocking films  251  are not limited to four. 
     Forming the slits in different directions pixel by pixel as described above, in other words, varying the directions in which the slits are formed on the light-blocking films  251  formed on the adjacent second opto-electronic converters  103  pixel by pixel can block the polarized light from different directions. 
     Additionally, when the direction in which the slits are formed varies depending on the pixel as described above, for example, when the slits are formed in different directions in the four pixels illustrated in  FIG. 24C , respectively, the four unit pixels can have the same color. In other words, the colors can be arranged in Bayer arrangement in which the four pixels have the same color as illustrated in  FIG. 23B , and the slits can be formed in different directions in the four pixels having the same color, respectively. 
     Exemplary Variation 
     An example in which two opto-electronic converters with different sensitivities are arranged in a pixel has been described above. However, three or more opto-electronic converters with different sensitivities can be arranged in a pixel. The difference of the sensitivities can be adjusted by changing the material or thickness of the light-blocking film. 
     Additionally, an example in which the present technology is applied to a CMOS image sensor having unit pixels arranged in rows and columns has been described in the embodiments. However, the application of the present technology is not limited to the application to a CMOS image sensor. In other words, the present technology can be applied to all of image pick-up apparatuses in which unit pixels are two-dimensionally in rows and columns in an X-Y address scheme. 
     Furthermore, the present technology can be applied not only to an image pick-up apparatus that detects the distribution of visible incident lights and captures the lights as an image but also to all the image pick-up apparatuses that capture the distribution of incoming infrared rays, X-rays, or particles as an image. 
     Note that the image pick-up apparatus can be formed as a chip, or can be formed as a module having an image pick-up function in which an image pick-up unit and a signal processing unit or an optical system are packaged. 
     Exemplary Usage of Image Pick-Up Apparatus 
       FIG. 25  is a diagram of exemplary uses of the image pick-up apparatus. 
     The image pick-up apparatus can be used for various purposes in which lights including visible lights, infrared rays, ultraviolet lights, or X rays are sensed as described below.
         An apparatus that captures an image for appreciation, such as a digital camera, or a mobile phone with a camera function.   An apparatus used for traffic purposes, such an in-vehicle sensor that captures an image of the view in front of, around, behind, or in the car for safe driving including automatic stop and recognition of the driver&#39;s condition, a monitoring camera that monitors running vehicles, or roads, or a distance measurement sensor that measures the distance between the vehicle and another vehicle.   An apparatus used for home electrical appliances including a TV, a refrigerator, and an air conditioner. The apparatus captures an image of the user&#39;s gesture to control the appliance in accordance with the gesture.   An apparatus used for medical care or health care, such as an endoscope or a device that captures an image of vessels by receiving infrared lights.   An apparatus used for security, such as a monitoring camera for security or a camera used for personal verification.   An apparatus used for cosmetic purposes, such as a skin condition measurement device that captures an image of skin, or a microscope takes an image of the scalp.   An apparatus used for sport, such as an action camera or a wearable camera for sports.   An apparatus used for agricultural purposes, such as a camera that monitors fields and crops.       

       FIG. 26  is a block diagram of an exemplary configuration of an image pick-up apparatus (camera device)  1001  that is an exemplary electronic device using the present technology. 
     As illustrated in  FIG. 26 , the image pick-up apparatus  1001  includes, for example, an optical system including a lens group  1011 , an image pick-up element  1012 , a DSP  1013  that is a camera signal processing unit, a frame memory  1014 , a display device  1015 , a recording device  1016 , an operation system  1017 , and a power-supply system  1018 . The DSP  1013 , the frame memory  1014 , the display device  1015 , the recording device  1016 , the operation system  1017 , and the power-supply system  1018  are connected to each other via a bus line  1019 . 
     The lens group  1011  captures the incident light (image light) from an object and forms an image on the image pick-up surface of the image pick-up element  1012 . The image pick-up element  1012  converts the amount of incident light with which the lens group  1011  forms an image on the image pick-up surface into electric signals pixel by pixel so as to output the electric signals as pixel signals. 
     The display device  1015  includes a panel display device such as a liquid crystal display device or an organic electro luminescence (EL) display device so as to display the video or still image captured by the image pick-up element  1012 . The recording device  1016  records the video or still image captured by the image pick-up element  1012  onto a recording medium such as a memory card, a videotape, or a Digital Versatile Disk (DVD). 
     The operation system  1017  issues instructions for the operation of various functions of the image pick-up apparatus  1001  under the control by the user. The power-supply system  1018  properly supplies various power sources as the power sources of the operation of the DSP  1013 , the frame memory  1014 , the display device  1015 , the recording device  1016 , and the operation system  1017 . 
     The image pick-up apparatus  1001  described above is applied to a video camera, or a digital still camera, additionally, to a camera module for a mobile device such as a smartphone, or a mobile phone. The image pick-up apparatus  1001  can use the image pick-up apparatus described in each of the embodiments described above as the image pick-up element  1012 . This can improve the image quality of images captured by the image pick-up apparatus  1001 . 
     Herein, the system means the whole of an apparatus including a plurality of devices. 
     Note that the effects described herein are merely examples. The effects of the present technology are not limited to the described effects and can include another effect. 
     Note that the embodiments of the present technology are not limited to the embodiments described above and can variously be changed without departing from the gist of the present technology. 
     Note that the present technology can have the following configurations. 
     (1) 
     An image pick-up apparatus including: 
     a pixel array unit, a plurality of unit pixels being arranged in the pixel array unit, the unit pixel including 
     a first opto-electronic converter, and 
     a second opto-electronic converter having a sensitivity lower than a sensitivity of the first opto-electronic converter, 
     the second opto-electronic converter including a light-blocking film formed on a side of the second opto-electronic converter from which light enters the second opto-electronic converter. 
     (2) 
     The image pick-up apparatus according to (1), wherein a lens used to collect light entering the second opto-electronic converter is not formed on the second opto-electronic converter. 
     (3) 
     The image pick-up apparatus according to (1) or (2), wherein a light-blocking wall used to prevent light from leaking from an opto-electronic converter into opto-electronic converters next to the opto-electronic converter is provided between the opto-electronic converters. 
     (4) 
     The image pick-up apparatus according to any of (1) to (3), wherein the light-blocking film has a slit. 
     (5) 
     The image pick-up apparatus according to (4), wherein directions in which slits are formed on light-blocking films formed on the adjacent second opto-electronic converters are different. 
     (6) 
     The image pick-up apparatus according to any of (1) to (5), being a backside-illumination image sensor. 
     (7) 
     The image pick-up apparatus according to any of (1) to (5), being a front-side-illumination image sensor. 
     (8) 
     The image pick-up apparatus according to (7), wherein the light-blocking film is formed on a lower or upper side of a wiring layer formed on the second opto-electronic converter. 
     (9) 
     The image pick-up apparatus according to any of (1) to (8), wherein the light-blocking film is an amorphous silicon film, a polysilicon film, a Ge film, a GaN film, a CdTe film, a GaAs film, an InP film, a CuInSe2 film, Cu2S, a CIGS film, a non-conductive carbon film, a black resist film, an organic opto-electronic conversion film, or a metal film. 
     (10) 
     An imaging device, comprising: 
     a substrate; 
     a first opto-electronic converter having a first area formed in the substrate; 
     a second opto-electronic converter having a second area formed in the substrate, wherein the first area is larger than the second area; 
     a trench extending from a first surface of the substrate, wherein at least a portion of the trench is between the first opto-electronic converter and the second opto-electronic converter. 
     (11) 
     The imaging device according to (10), wherein the first and second areas are parallel to the first surface of the substrate. 
     (12) 
     The imaging device according to (10) or (11), wherein the first and second areas correspond to light-receiving surfaces of the first and second opto-electronic converters respectively. 
     (13) 
     The imaging device according to any of (10) to (12), wherein the first opto-electronic converter has a higher sensitivity than the second opto-electronic converter. 
     (14) 
     The imaging device according to any of (10) to (13), further comprising a pixel separation region between the first and second opto-electronic converters, wherein the trench is formed in the pixel separation region. 
     (15) 
     The imaging device according to any of (10) to (14), wherein a light-blocking wall is formed in the trench and includes an insulating film extending from the first surface of the substrate. 
     (16) 
     The imaging device according to any of (10) to (15), wherein a light-blocking wall is formed in the trench, and wherein the light-blocking wall includes at least one of a negative fixed charge film, an oxide film, and a metal. 
     (17) 
     The imaging device according to any of (10) to (16), further comprising a light-blocking film, wherein the light-blocking film is formed over at least a portion of the second area of the second opto-electronic converter, wherein the light-blocking film absorbs a portion of light incident on the imaging device. 
     (18) 
     The imaging device according to any of (10) to (17), wherein the light-blocking film overlaps the trench. 
     (19) 
     The imaging device according to any of (10) to (18), wherein the light-blocking film overlaps a portion of the first opto-electronic converter. 
     (20) 
     The imaging device according to any of (10) to (19), further comprising an on-chip lens formed over the first area of the opto-electronic converter, wherein no on-chip lens is formed over the second area of the second opto-electronic converter. 
     (21) 
     The imaging device according to any of (10) to (20), further comprising a color filter, wherein the color filter extends across at least a portion of the first area of the first opto-electronic converter. 
     (22) 
     The imaging device according to any of (10) to (21), wherein the color filter extends across the light-blocking film. 
     (23) 
     The imaging device according to any of (10) to (22), wherein the light-blocking film includes a slit. 
     (24) 
     The imaging device according to any of (10) to (23), wherein the light-blocking film forms a polarizer. 
     (25) 
     The imaging device according to any of (10) to (24) further comprising a plurality of light-blocking walls, wherein the first opto-electronic converter extends from a first light-blocking wall to a second light-blocking wall to a third light-blocking wall. 
     (26) 
     The imaging device according to any of (10) to (25) further comprising a plurality of first opto-electronic converters, wherein the first opto-electronic converters are disposed in a plurality of rows and a plurality if columns; 
     a plurality of second opto-electronic converters, wherein the second opto-electronic converters are disposed in a plurality of rows and a plurality of columns, wherein a centerline of at least one of the rows of the plurality of first opto-electronic converters does not intersect any of the second optoelectronic converters, wherein a centerline of at least one of the rows of the plurality of second opto-electronic converters does not intersect any of the first optoelectronic converters, and wherein a line diagonal to at least one of the rows intersects at least one of the first opto-electronic converters and at least one of the second opto-electronic converters. 
     (27) 
     An imaging device, comprising: 
     a substrate; 
     a first opto-electronic converter; 
     a second opto-electronic converter having a sensitivity lower than a sensitivity of the first opto-electronic converter; 
     a trench extending from a first surface of the substrate, wherein at least a portion of the trench is between the first opto-electronic converter and the second opto-electronic converter. 
     (28) 
     An electronic apparatus, comprising: 
     an optical system; 
     an image pick-up element that receives light from the optical system, the image pick-up element, including: 
     a substrate; 
     a first opto-electronic converter having a first area formed in the substrate; 
     a second opto-electronic converter having a second area formed in the substrate, wherein the first area is larger than the second area; 
     a light-blocking wall extending from a first surface of the substrate, wherein at least a portion of the light-blocking wall is between the first opto-electronic converter and the second opto-electronic converter; 
     a digital signal processor that processes signals received from the image pick-up element. 
     (29) 
     The electronic apparatus according to (28), wherein the electronic apparatus is included in a vehicle. 
     REFERENCE SIGNS LIST 
     
         
           10  CMOS image sensor 
           11  Pixel array unit 
           12  Vertical drive unit 
           13  Column processing unit 
           14  Horizontal drive unit 
           15  System control unit 
           16  Pixel drive line 
           17  Vertical signal line 
           18  Signal processing unit 
           19  Data storage unit 
           100  Unit pixel 
           101  First opto-electronic converter 
           102  First transfer gate unit 
           103  Second opto-electronic converter 
           104  Second transfer gate unit 
           105  Third transfer gate unit 
           106  Charge accumulation unit 
           107  Reset gate unit 
           108  FD unit 
           109  Amplification transistor 
           110  Selection transistor 
           151  Fourth transfer gate unit 
           203 ,  251 ,  303 ,  331 ,  351 , and  381  Light-blocking film