Patent Publication Number: US-11659724-B2

Title: Solid-state imaging apparatus and electronic apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. Serial application Ser. No. 17/069,610 filed Oct. 13, 2021, which is a continuation application of U.S. Serial application Ser. No. 16/301,105 filed Nov. 13, 2018, now U.S. Pat. No. 10,847,581, which is a national stage application under 35 U.S.C. 371 and claims the benefit of PCT Application No. PCT/JP2017/017281 having an international filing date of May 2, 2017, which designated the United States, which PCT application claimed the benefit of Japanese Patent Application No. 2016-101076 filed May 20, 2016, the entire disclosures of each of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present technology relates to a solid-state imaging apparatus and an electronic apparatus, and particularly to a solid-state imaging apparatus capable of generating a high-resolution IR image while keeping high quality of a visible light image, and an electronic apparatus. 
     BACKGROUND ART 
     An image sensor shoots an image obtained by visible lights (denoted as visible light image below) by use of R (read), G (green), and B (blue) color filters. Further, an image sensor shoots an image obtained by infrared rays (IR) (denoted as IR image below) by detecting from a visible light to an infrared ray without the use of color filters in order to improve a night-vision sensitivity and to acquire object information which cannot be shot by a visible light in addition to a visible light image. 
     On the other hand, not acquiring either a visible light image or an IR image at one time, a demand to acquire both a visible light image and an IR image at the same time has increased. For example, there is known, as a pixel layout pattern, a configuration in which IR pixels corresponding to the IR component are two-dimensionally arranged in addition to R pixels corresponding to the R component, G pixels corresponding to the G component, and B pixels corresponding to the B component thereby to acquire a visible light image and an IR image at the same time. 
     Further, there is disclosed a configuration in which an infrared photoelectric conversion layer configured to absorb a light in an infrared region is formed above a semiconductor substrate in which photodiodes configured to detect lights of R component, G component, and B component are formed thereby to acquire a visible light image and an IR image at the same time (see Patent Document 1, for example). 
     CITATION LIST 
     Patent Document 
     Patent Document 1: Japanese Patent Application Laid-Open No. 2009-27063 
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     In the pixel structure disclosed in Patent Document 1, the infrared photoelectric conversion layer configured to absorb a light in an infrared region is provided for all the pixels, and an IR image using IR signals obtained from all the IR pixels can be acquired. 
     On the other hand, in the pixel structure disclosed in Patent Document 1, an inorganic filter (filter including an inorganic material) formed below the infrared photoelectric conversion layer disperses the color components without providing color filters configured to disperse the color components of lights detected by the photodiodes above the infrared photoelectric conversion layer. 
     Here, the spectroscopic shape of a light obtained by the inorganic filter is inferior to the spectroscopic shape of a light obtained by the color filters, and thus the quality of a visible light image using RGB signals obtained from R pixels, G pixels, and B pixels is lower in using the inorganic filter than in using the color filters. Therefore, a technology for generating a high-resolution IR image while keeping high quality of a visible light image has been required. 
     The present technology has been made in terms of such situations, and is directed to generating a high-resolution IR image while keeping high quality of a visible light image. 
     Solutions to Problems 
     A solid-state imaging apparatus according to an aspect of the present technology is a solid-state imaging apparatus including: a pixel array part in which pixels each having a first photoelectric conversion region formed above a semiconductor layer and a second photoelectric conversion region formed in the semiconductor layer are two-dimensionally arranged, in which each of the pixels further has: a first filter configured to transmit a light in a predetermined wavelength region corresponding to a color component; and a second filter having different transmission characteristics from the first filter, one photoelectric conversion region out of the first photoelectric conversion region and the second photoelectric conversion region photoelectrically converts a light in a visible light region and the other photoelectric conversion region photoelectrically converts a light in an infrared region, the first filter is formed above the first photoelectric conversion region, and the second filter has transmission characteristics of making wavelengths of lights in an infrared region absorbed in the other photoelectric conversion region formed below the first filter the same. 
     In a solid-state imaging apparatus according to one aspect of the present technology, each of pixels two-dimensionally arranged in a pixel array part has a first photoelectric conversion region formed above a semiconductor layer, a second photoelectric conversion region formed in the semiconductor layer, a first filter configured to transmit a light in a predetermined wavelength region corresponding to a color component, and a second filter having different transmission characteristics from the first filter. Then, one photoelectric conversion region out of the first photoelectric conversion region and the second photoelectric conversion region photoelectrically converts a light in a visible light region, and the other photoelectric conversion region photoelectrically converts a light in an infrared region. Further, the second filter uniforms wavelengths of lights in an infrared region absorbed in the other photoelectric conversion region formed below the first filter. 
     An electronic apparatus according to an aspect of the present technology is an electronic apparatus mounting a solid-state imaging apparatus thereon, the solid-state imaging apparatus including: a pixel array part in which pixels each having a first photoelectric conversion region formed above a semiconductor layer and a second photoelectric conversion region formed in the semiconductor layer are two-dimensionally arranged, in which each of the pixels further has: a first filter configured to transmit a light in a predetermined wavelength region corresponding to a color component; and a second filter having different transmission characteristics from the first filter, one photoelectric conversion region out of the first photoelectric conversion region and the second photoelectric conversion region photoelectrically converts a light in a visible light region, and the other photoelectric conversion region photoelectrically converts a light in an infrared region, the first filter is formed above the first photoelectric conversion region, and the second filter has characteristics of making wavelengths of lights in an infrared region absorbed in the other photoelectric conversion region formed below the first filter the same. 
     In an electronic apparatus according to one aspect of the present technology, each of pixels two-dimensionally arranged in a pixel array part in a solid-state imaging apparatus mounted thereon has a first photoelectric conversion region formed above a semiconductor layer, a second photoelectric conversion region formed in the semiconductor layer, a first filter configured to transmit a light in a predetermined wavelength region corresponding to a color component, and a second filter having different transmission characteristics from the first filter. Then, one photoelectric conversion region out of the first photoelectric conversion region and the second photoelectric conversion region photoelectrically converts a light in a visible light region, and the other photoelectric conversion region photoelectrically converts a light in an infrared region. Further, the second filter uniforms wavelengths of lights in an infrared region absorbed in the other photoelectric conversion region formed below the first filter. 
     Additionally, each of the solid-state imaging apparatus and the electronic apparatus according to one aspect of the present technology may be an independent apparatus, or may be an internal block configuring one apparatus. 
     Effects of the Invention 
     According to one aspect of the present technology, it is possible to generate a high-resolution IR image while keeping high quality of a visible light image. 
     Additionally, the effects described herein are not necessarily restrictive, and any effect described in the present disclosure may be obtained. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a diagram illustrating one embodiment of a solid-state imaging apparatus according to the present technology. 
         FIG.  2    is a cross-section view illustrating a structure of pixels. 
         FIG.  3    is a diagram illustrating transmissivity of color filters in each wavelength band. 
         FIG.  4    is a diagram illustrating an absorption rate of an organic photoelectric conversion layer in each wavelength band. 
         FIG.  5    is a diagram illustrating absorption rates of an R pixel, a G pixel, and a B pixel in each wavelength band. 
         FIG.  6    is a diagram illustrating transmissivity of an R filter, a G filter, and a B filter in each wavelength band. 
         FIG.  7    is a diagram for explaining that a light spectrum detected per IR pixel is different. 
         FIG.  8    is a cross-section view illustrating a structure of pixels according to a first embodiment. 
         FIG.  9    is a diagram illustrating transmissivity of a dual-bandpass filter in each wavelength band. 
         FIG.  10    is a diagram illustrating characteristics of each pixel before the dual-bandpass filter is inserted. 
         FIG.  11    is a diagram illustrating characteristics of each pixel after the dual-bandpass filter is inserted. 
         FIG.  12    is a diagram for explaining that a light spectrum detected per IR pixel is the same. 
         FIG.  13    is a cross-section view of a structure of pixels according to a second embodiment. 
         FIG.  14    is a diagram illustrating a structure of a multilayered filter. 
         FIG.  15    is a diagram illustrating transmissivity of the multilayered filter in each wavelength band. 
         FIG.  16    is a diagram illustrating characteristics of each pixel before the multilayered filter is inserted. 
         FIG.  17    is a diagram illustrating characteristics of each pixel after the multilayered filter is inserted. 
         FIG.  18    is a cross-section view illustrating a structure of pixels according to a third embodiment. 
         FIG.  19    is a diagram illustrating a structure of a plasmon filter. 
         FIG.  20    is a cross-section view illustrating a structure of pixels according to a fourth embodiment. 
         FIG.  21    is a diagram illustrating transmissivity of a dual-bandpass filter in each wavelength band. 
         FIG.  22    is a diagram illustrating characteristics of each pixel before the dual-bandpass filter is inserted. 
         FIG.  23    is a diagram illustrating characteristics of each pixel after the dual-bandpass filter is inserted. 
         FIG.  24    is a cross-section view illustrating a structure of pixels according to a fifth embodiment. 
         FIG.  25    is a diagram illustrating transmissivity of a multilayered filter in each wavelength band. 
         FIG.  26    is a diagram illustrating a readout circuit for an organic photoelectric conversion layer. 
         FIG.  27    is a diagram illustrating a readout circuit for a photodiode. 
         FIG.  28    is a cross-section view illustrating other structure of the pixels according to the first embodiment. 
         FIG.  29    is a cross-section view illustrating other structure of the pixels according to the second embodiment. 
         FIG.  30    is a cross-section view illustrating other structure of the pixels according to the third embodiment. 
         FIG.  31    is a cross-section view illustrating other structure of the pixels according to the fourth embodiment. 
         FIG.  32    is a cross-section view illustrating other structure of the pixels according to the fifth embodiment. 
         FIG.  33    is a diagram illustrating an exemplary configuration of an electronic apparatus having a solid-state imaging apparatus. 
         FIG.  34    is a diagram illustrating exemplary use of the solid-state imaging apparatus. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     Embodiments of the present technology will be described below with reference to the drawings. Additionally, the description will be made in the following order. 
     1. Configuration of solid-state imaging apparatus 
     2. First embodiment: structure using dual-bandpass filter (OPC: RGB pixels, PD: IR pixels) 
     3. Second embodiment: structure using multilayered filter (OPC: RGB pixels, PD: IR pixels) 
     4. Third embodiment: structure using plasmon filter (OPC: RGB pixels, PD: IR pixels) 
     5. Fourth embodiment: structure using dual-bandpass filter (OPC: IR pixels, PD: RGB pixels) 
     6. Fifth embodiment: structure using multilayered filter (OPC: IR pixels, PD: RGB pixels) 
     7. Readout circuit 
     8. Variant 
     9. Configuration of electronic apparatus 
     10. Exemplary use of solid-state imaging apparatus 
     1. Configuration of Solid-State Imaging Apparatus 
     (Exemplary Configuration of Solid-State Imaging Apparatus) 
       FIG.  1    is a diagram illustrating one embodiment of a solid-state imaging apparatus according to the present technology. 
     A CMOS image sensor  10  of  FIG.  1    is a solid-state imaging apparatus using complementary metal oxide semiconductor (CMOS). The CMOS image sensor  10  takes in an incident light (image light) from an object via an optical lens system (not illustrated), converts the amount of the incident light formed on the imaging surface into electric signals in units of pixel, and outputs the electric signals as pixel signals. 
     In  FIG.  1   , the CMOS image sensor  10  is configured of a pixel array part  11 , a vertical drive circuit  12 , column signal processing circuits  13 , a horizontal drive circuit  14 , an output circuit  15 , a control circuit  16 , and an I/O terminal  17 . 
     A plurality of pixels  100  are two-dimensionally arranged in the pixel array part  11 . A pixel  100  is configured of an organic photoelectric conversion layer (OPC) as a photoelectric conversion region and a photodiode (PD) as well as a plurality of pixel transistors. 
     The vertical drive circuit  12  is configured of a shift register, for example, selects a predetermined pixel drive line  21 , supplies the selected pixel drive line  21  with a pulse for driving the pixels  100 , and drives the pixels  100  in units of row. That is, the vertical drive circuit  12  selects and scans the respective pixels  100  in the pixel array part  11  in units of row sequentially in the vertical direction, and supplies the pixel signals based on signal charges (charges) generated depending on the amount of received light in the organic photoelectric conversion layer or the photodiodes in the respective pixels  100  to the column signal processing circuits  13  via vertical signal lines  22 . 
     The column signal processing circuits  13  are arranged in units of column of the pixels  100 , and perform a signal processing such as noise cancellation on the signals output from one row of pixels  100  per column of pixels. For example, the column signal processing circuits  13  perform a signal processing such as correlated double sampling (CDS) for canceling a pixel-specific fixed pattern noise and analog/digital (A/D) conversion. 
     The horizontal drive circuit  14  is configured of a shift register, for example, sequentially outputs a horizontal scanning pulse, selects each of the column signal processing circuits  13  in turn, and causes pixel signals to be output from each of the column signal processing circuits  13  to a horizontal signal line  23 . 
     The output circuit  15  performs a signal processing on and outputs the signals sequentially supplied from each of the column signal processing circuits  13  via the horizontal signal line  23 . Additionally, the output circuit  15  may perform only buffering, for example, or may perform black level adjustment, column variation correction, various digital signal processings, and the like. 
     The control circuit  16  controls the operations of each part in the CMOS image sensor  10 . For example, the control circuit  16  receives an input clock signal and data for giving an instruction on an operation mode or the like, and outputs data such as internal information of the CMOS image sensor  10 . That is, the control circuit  16  generates clock signals or control signals as the references of the operations of the vertical drive circuit  12 , the column signal processing circuits  13 , the horizontal drive circuit  14 , and the like on the basis of a vertical synchronization signal, a horizontal synchronization signal, and a master clock signal. The control circuit  16  outputs the generated clock signals or control signals to the vertical drive circuit  12 , the column signal processing circuits  13 , the horizontal drive circuit  14 , and the like. 
     The I/O terminal  17  exchanges signals with the outside. 
     The thus-configured CMOS image sensor  10  of  FIG.  1    is assumed as a CMOS image sensor in a column AD system in which the column signal processing circuits  13  configured to perform the CDS processing and the A/D conversion processing are arranged per column of pixels. Further, the CMOS image sensor  10  of  FIG.  1    may be assumed as a CMOS image sensor of backside irradiation type or surface irradiation type. Additionally, the configuration illustrated in  FIG.  1    is exemplary, and may be different depending on a configuration of a readout circuit (for the organic photoelectric conversion layer and the photodiode) of a pixel  100 , for example. For example, in a case where the readout circuit for the organic photoelectric conversion layer employs a system in which a memory part for reducing noises is provided, not the above CDS processing but an external memory part is used to cancel noises. 
     Incidentally, the structure of the pixels  100  two-dimensionally arranged in the pixel array part  11  in the CMOS image sensor  10  may employ the structures of pixels according to a first embodiment to a fifth embodiment described below. The structures of pixels according to the first embodiment to the fifth embodiment arranged in the pixel array part  11  will be described below. 
     Additionally, the pixels according to the first embodiment are denoted as pixels  100  and are discriminated from the pixels according to the other embodiments in the following description for convenient description. Similarly, the pixels according to the second embodiment to the fifth embodiment are denoted as pixels  200 , pixel  300 , pixels  400 , and pixels  500 , respectively, but the pixels are also two-dimensionally arranged in the pixel array part  11  in the CMOS image sensor  10  ( FIG.  1   ). 
     2. First Embodiment: Structure Using Dual-Bandpass Filter (OPC: RGB Pixels, PD: IR Pixels) 
     A structure of the pixels  100  according to the first embodiment will be first described with reference to  FIG.  2    to  FIG.  12   . 
     (Structure of Pixels) 
       FIG.  2    is a cross-section view illustrating a structure of the pixels  100 .  FIG.  2    illustrates three pixels  100 - 1  to  100 - 3  arranged at arbitrary positions among a plurality of pixels  100  two-dimensionally arranged in the pixel array part  11  by way of example. However, the pixels  100 - 1  to  100 - 3  employ a structure of backside irradiation type. 
     Photodiodes  115 - 1  to  115 - 3  and charge holding parts  124 - 1  to  124 - 3  are formed in a semiconductor layer  114  including silicon (Si) or the like in the pixels  100 - 1  to  100 - 3 , respectively. A wiring layer  116  is assumed below the semiconductor layer  114 , where a plurality of wirings  131  are formed. Further, an interlayer insulative film  113  and an organic photoelectric conversion layer  112  are laminated on the semiconductor layer  114 . 
     The organic photoelectric conversion layer  112  absorbs only lights in the visible light region, and generates signal charges (charge) corresponding to lights of the respective color components of R (red) component, G (green) component, and B (blue) component. A transparent electrode  121  configured to read out a signal charge generated in the organic photoelectric conversion layer  112 , and transparent electrodes  122 - 1  to  122 - 3  are formed on the top and back of the organic photoelectric conversion layer  112 , respectively. 
     Additionally, the transparent electrode  121  is formed on the entire surface of the organic photoelectric conversion layer  112 . Further, the transparent electrodes  122 - 1  to  122 - 3  are formed depending on a pixel pitch. The transparent electrode  122 - 1  is connected to the charge holding part  124 - 1  via an electrode  123 - 1 . Similarly, the transparent electrodes  122 - 2  and  122 - 3  are connected to the charge holding parts  124 - 2  and  124 - 3  via electrodes  123 - 2  and  123 - 3 , respectively. 
     An R color filter  111 - 1  configured to transmit an R-component light is formed on the side in which a light is incident of the pixel  100 - 1  among the pixels  100 - 1  to  100 - 3 . Similarly, a G color filter  111 - 2  configured to transmit a G-component light is formed on the side in which a light is incident of the pixel  100 - 2 . Further, a B color filter  111 - 3  configured to transmit a B-component light is formed on the side in which a light is incident of the pixel  100 - 3 . 
     That is, in the pixel  100 - 1 , an R-component light in the visible light region among the lights transmitting through the R color filter  111 - 1  is absorbed in the organic photoelectric conversion layer  112  while an IR-component light in the infrared region transmits through the organic photoelectric conversion layer  112 . Thus, a signal charge corresponding to the R-component light is generated in the organic photoelectric conversion layer  112  in the pixel  100 - 1 . On the other hand, a signal charge corresponding to the IR-component light is generated in the photodiode  115 - 1 . 
     Further, in the pixel  100 - 2 , a G-component light in the visible light region among the lights transmitting through the G color filter  111 - 2  is absorbed in the organic photoelectric conversion layer  112  while an IR-component light in the infrared region transmits through the organic photoelectric conversion layer  112 . Thus, a signal charge corresponding to the G-component light is generated in the organic photoelectric conversion layer  112  in the pixel  100 - 2 . On the other hand, a signal charge corresponding to the IR-component light is generated in the photodiode  115 - 2 . 
     Further, in the pixel  100 - 3 , a B-component light in the visible light region among the lights transmitting through the B color filter  111 - 3  is absorbed in the organic photoelectric conversion layer  112  while an IR-component light in the infrared region transmits through the organic photoelectric conversion layer  112 . Thus, a signal charge corresponding to the B-component light is generated in the organic photoelectric conversion layer  112  in the pixel  100 - 3 . On the other hand, a signal charge corresponding to the IR-component light is generated in the photodiode  115 - 3 . 
     An R signal and an IR signal are generated in the pixel  100 - 1  in this way. Further, a G signal and an IR signal are generated in the pixel  100 - 2 , and a B signal and an IR signal are generated in the pixel  100 - 3 . That is, in the respective pixels  100  two-dimensionally arranged in the pixel array part  11 , the IR-component signals are acquired in addition to the signals of color components depending on the type of a color filter, thereby generating a visible light image and an IR image at the same time. 
     Additionally, the configuration including the organic photoelectric conversion layer  112  configured to generate an R signal is denoted as R pixel  100 - 1 -R and the configuration including the photodiode  115 - 1  configured to generate an IR signal is denoted as IR pixel  100 - 1 -IR in the pixel  100 - 1  in the following description for convenient description. That is, the pixel  100 - 1  may be both the R pixel  100 - 1 -R and the IR pixel  100 - 1 -IR R . 
     Similarly, the configuration including the organic photoelectric conversion layer  112  configured to generate a G signal is denoted as G pixel  100 - 2 -G and the configuration including the photodiode  115 - 2  configured to generate an IR signal is denoted as IR pixel  100 - 2 -IR G  in the pixel  100 - 2 . That is, the pixel  100 - 2  may be both the G-pixel  100 - 2 -G and the IR pixel  100 - 2 -IR G . 
     Further, the configuration including the organic photoelectric conversion layer  112  configured to generate a B signal is denoted as B pixel  100 - 3 -B and the configuration including the photodiode  115 - 3  configured to generate an IR signal is denoted as IR pixel  100 - 3 -IR B  in the pixel  100 - 3 . That is, the pixel  100 - 3  may be both the B pixel  100 - 3 -B and the IR pixel  100 - 3 -IR B . 
     Further, in a case where the R color filter  111 - 1 , the G color filter  111 - 2 , and the B color filter  111 - 3  do not need to be particularly discriminated, they will be simply denoted as color filters  111  in the following description. Further, in a case where the photodiode  115 - 1 , the photodiode  115 - 2 , and the photodiode  115 - 3  do not need to be particularly discriminated, they will be simply denoted as photodiodes  115 . Additionally, the relationships are similarly applied also in the other embodiments described below. 
     The pixels  100  of  FIG.  2    have the above structure, but a spectroscopic shape (spectroscopic characteristics) of an IR pixel in each pixel  100  is different depending on the type of a color filter  111  provided in the upper layer, and thus an IR image using the IR signals obtained from all the IR pixels cannot be generated. The reason will be described below. 
     (Transmissivity of Color Filters) 
     Here,  FIG.  3    illustrates transmissivity of the color filters  111  of  FIG.  2    in each wavelength band. In  FIG.  3   , the horizontal axis indicates wavelength (nm), the value of which is higher from the left side toward the right side in the Figure. Further, the vertical axis indicates transmissivity of each color filter  111 , the value of which is within a range of 0 to 1.0. 
     As illustrated in  FIG.  3   , the R color filter  111 - 1  has transmissivity corresponding to a wavelength region (a range of 600 to 650 nm, 550 to 650 nm, or the like, for example) of an R-component light in order to extract the R-component light. Further, the G color filter  111 - 2  has transmissivity corresponding to a wavelength region (a range of 500 to 600 nm, or the like, for example) of a G-component light in order to extract the G-component light. Further, the B color filter  111 - 3  has transmissivity corresponding to a wavelength region (a range of 450 to 500 nm, 400 to 500 nm, or the like, for example) of a B-component light in order to extract the B-component light. 
     Further, as illustrated in  FIG.  3   , each color filter  111  transmits lights in the regions other than the visible light region, but the R color filter  111 - 1 , the G color filter  111 - 2 , and the B color filter  111 - 3  are different in transmissivity at a wavelength of 700 nm or more, and their transmissivity varies. 
     (Absorption Rate of Organic Photoelectric Conversion Layer) 
       FIG.  4    illustrates an absorption rate of the organic photoelectric conversion layer  112  of  FIG.  2    in each wavelength band. The horizontal axis indicates wavelength (nm) and the vertical axis indicates absorption rate in  FIG.  4   . 
     In  FIG.  4   , the organic photoelectric conversion layer  112  has an absorption rate corresponding to a wavelength region (a range of 400 nm to 760 nm, or the like, for example) of lights in the visible light region. Additionally, the organic photoelectric conversion layer  112  may employ a bulk-hetero structure using P3HT or PCBM, and the like, for example. 
     (Absorption Rates of R, G, and B Pixels) 
       FIG.  5    illustrates absorption rates of the pixels of the respective color components such as the R pixel  100 - 1 -R, the G pixel  100 - 2 -G, and the B pixel  100 - 3 -B of  FIG.  2    in each wavelength band. The horizontal axis indicates wavelength (nm) and the vertical axis indicates absorption rate in  FIG.  5   . 
     In  FIG.  5   , the absorption rate of the R pixel  100 - 1 -R configured of the organic photoelectric conversion layer  112  corresponds to a spectroscopic shape obtained by multiplying the transmissivity of the R color filter  111 - 1  of  FIG.  3    by the absorption rate of the organic photoelectric conversion layer  112  of  FIG.  4   . That is, the R pixel  100 - 1 -R has an absorption rate corresponding to the wavelength region (a range of 600 to 650 nm, 550 to 650 nm, or the like, for example) of the R-component light, but does not absorb and transmits lights (infrared rays) with a wavelength outside the wavelength region of the R-component light. 
     Similarly, the absorption rate of the G pixel  100 - 2 -G configured of the organic photoelectric conversion layer  112  corresponds to a spectroscopic shape obtained by multiplying the transmissivity of the G color filter  111 - 2  of  FIG.  3    by the absorption rate of the organic photoelectric conversion layer  112  of  FIG.  4   . That is, the G pixel  100 - 2 -G has an absorption rate corresponding to the wavelength region (a range of 500 to 600 nm, or the like, for example) of the G-component light, but transmits lights (infrared rays) with a wavelength outside the wavelength region of the G-component light. 
     Further, the absorption rate of the B pixel  100 - 3 -B configured of the organic photoelectric conversion layer  112  corresponds to a spectroscopic shape obtained by multiplying the transmissivity of the B color filter  111 - 3  of  FIG.  3    by the absorption rate of the organic photoelectric conversion layer  112  of  FIG.  4   . That is, the B pixel  100 - 3 -B has an absorption rate corresponding to the wavelength region (a range of 450 to 500 nm, 400 to 500 nm, or the like, for example) of the B-component light, but transmits lights with a wavelength outside the wavelength region of the B-component light. 
     (Transmissivity into IR Pixels) 
       FIG.  6    illustrates transmissivity into the respective IR pixels of the IR pixel  100 - 1 -IR R , the IR pixel  100 - 2 -IR G , and the IR pixel  100 - 3 -IR B  arranged below the color filters  111  of  FIG.  2   , respectively. The horizontal axis indicates wavelength (nm) and the vertical axis indicates transmissivity in  FIG.  6   . 
     In  FIG.  6   , a light which transmits through the R color filter  111 - 1  and the organic photoelectric conversion layer  112  and is detected by (absorbed in) the IR pixel  100 - 1 -IR configured of the photodiode  115 - 1  is indicated in a wave pattern with “IR R ”. 
     Similarly, in  FIG.  6   , a light which transmits through the G color filter  111 - 2  and the organic photoelectric conversion layer  112  and is detected by (absorbed in) the IR pixel  100 - 2 -IR G  configured of the photodiode  115 - 2  is indicated in a wave pattern with “JR”. Further, a light which transmits through the B color filter  111 - 3  and the organic photoelectric conversion layer  112  and is detected by (absorbed in) the IR pixel  100 - 3 -IR B  configured of the photodiode  115 - 3  is indicated in a wave pattern with “IR B ”. 
     As illustrated in  FIG.  6   , a spectrum of the IR-component light absorbed in the IR pixel  100 - 1 -IR R , a spectrum of the IR-component light absorbed in the IR pixel  100 - 2 -IR C , and a spectrum of the IR-component light absorbed in the IR pixel  100 - 3 -IR B  are different. Thus, the IR pixel  100 - 1 -IR R , the IR pixel  100 - 2 -IR G , and the IR pixel  100 - 3 -IR B  are different in sensitivity per IR pixel, and cannot be used as IR pixels for generating the same IR image. 
     Here, for example, in a case where the pixels  100  illustrated in  FIG.  2    are two-dimensionally arranged in the Bayer layout in the pixel array part  11 , they can be expressed as the respective pixels illustrated in  FIG.  7   . A of  FIG.  7    illustrates an R pixel  100 - 1 -R, G pixels  100 - 2 -G, and a B pixel  100 - 3 -B which are configured of the organic photoelectric conversion layer  112  ( FIG.  2   ). That is, the G pixels  100 - 2 -G are checkerwise arranged and the R pixel  100 - 1 -R and the B pixel  100 - 3 -B are alternately arranged every column in the remaining parts in the pixel array part  11 . 
     Further, B of  FIG.  7    illustrates an IR pixel  100 - 1 -IR R , IR pixels  100 - 2 -IR G , and an IR pixel  100 - 3 -IR B  which are configured of the photodiodes  115  ( FIG.  2   ) embedded in the semiconductor layer  114  below the organic photoelectric conversion layer  112  ( FIG.  2   ). In B of  FIG.  7   , the spectra of the IR-component lights detected by (absorbed in) the IR pixel  100 - 1 -IR R , the IR pixels  100 - 2 -IR G , and the IR pixel  100 - 3 -IR B  are different as expressed in contrasting density of the respective IR pixels, and the sensitivity of the respective IR pixels is not the same. 
     In a case where the structure of the pixels  100  of  FIG.  2    is employed in this way, the spectrum (spectroscopic shape) of a light detected by (absorbed in) each IR pixel is different depending on the type of a color filter  111  provided thereon (varies due to a difference in transmissivity of a color filter  111 ), and thus each IR pixel substantially functions as a pixel for detecting other IR-component light. Consequently, an IR image using the IR signals obtained from all the IR pixels cannot be acquired and a high-resolution IR image cannot be acquired. 
     Thus, according to the present technology, a filter functioning as a spectroscopic adjustment layer is provided in order to uniform the spectra (spectroscopic shapes) of the lights detected by (absorbed in) the respective IR pixels provided below the color filters  111  so that the spectra of the lights detected by (absorbed in) the respective IR pixels are the same for all the IR pixels. With this arrangement, a high-quality visible light image using the RGB signals obtained from the R pixels, the G pixels, and the B pixels and a high-resolution IR image using the IR signals obtained from the IR pixels can be acquired at the same time. 
     (Structure of Pixels According to First Embodiment) 
       FIG.  8    is a cross-section view illustrating a structure of the pixels  100  according to the first embodiment. 
     The parts in the pixels  100  of  FIG.  8    corresponding to those in the pixels  100  of  FIG.  2    are denoted with the same reference numerals, and the description thereof will be omitted as needed. That is, the structure of the pixels  100  of  FIG.  8    is different from that of the pixels  100  of  FIG.  2    in that a dual-bandpass filter  141  is provided above the R color filter  111 - 1 , the G color filter  111 - 2 , and the B color filter  111 - 3 . 
     The dual-bandpass filter  141  has the transmission bands in the visible light region and the infrared region, respectively. 
     Here,  FIG.  9    illustrates transmissivity of the dual-bandpass filter  141  in each wavelength band. The horizontal axis indicates wavelength (nm) and the vertical axis indicates transmissivity in  FIG.  9   . As illustrated in  FIG.  9   , the dual-bandpass filter  141  has the transmission bands in a wavelength region (a range of 400 to 650 nm, or the like, for example) of the visible light region and in a wavelength region (a range of 800 to 900 nm, or the like, for example) of the infrared region, respectively, and transmits lights with a wavelength included in the transmission bands. 
     The dual-bandpass filter  141  is provided for the pixels  100  so that the spectrum of a light detected by (absorbed in) each IR pixel can be the same for all the IR pixels by the transmission band in the infrared region. A difference in transmissivity into each IR pixel before and after the dual-bandpass filter  141  is inserted will be described here with reference to  FIG.  10    and  FIG.  11   . 
     (Characteristics of Each Pixel Before Dual-Bandpass Filter is Inserted) 
       FIG.  10    is a diagram illustrating characteristics of each pixel before the dual-bandpass filter  141  is inserted. Additionally, the characteristics of the pixels illustrated in  FIG.  10    are the characteristics of the pixels before the dual-bandpass filter  141  is inserted, and correspond to the characteristics of the pixels  100  illustrated in  FIG.  2   . 
     A of  FIG.  10    illustrates absorption rates of the pixels of the respective color components configured of the organic photoelectric conversion layer  112  in each wavelength band. As illustrated in A of  FIG.  10   , the R pixel  100 - 1 -R can absorb a light (visible light) corresponding to the wavelength region of the R-component light. Further, the G pixel  100 - 2 -G can absorb a light corresponding to the wavelength region of the G-component light, and the B pixel  100 - 3 -B can absorb a light corresponding to the wavelength region of the B-component light. 
     Further, B of  FIG.  10    illustrates transmissivity into the IR pixels configured of the photodiodes  115  arranged below the color filters  111  of the respective color components. As illustrated in B of  FIG.  10   , the spectra of the IR-component lights detected by (absorbed in) the IR pixel  100 - 1 -IR R , the IR pixel  100 - 2 -IR G , and the IR pixel  100 - 3 -IR B  are different. That is, the sensitivity is different per IR pixel in the IR pixels, and as described above, the IR pixels cannot be used for generating the same IR image. 
     Additionally,  FIG.  10    illustrates the spectroscopic shapes before the dual-bandpass filter  141  is inserted, and thus A of  FIG.  10    illustrates that the absorption rates of the R pixel  100 - 1 -R, the G pixel  100 - 2 -G, and the B pixel  100 - 3 -B are similar to the absorption rates of the R, G, and B pixels illustrated in  FIG.  5   . Further, the transmissivity into the IR pixel  100 - 1 -IR R , the IR pixel  100 - 2 -IR G , and the IR pixel  100 - 3 -IR B  in B of  FIG.  10    is also similar to the transmissivity into the IR pixels illustrated in  FIG.  6   . 
     (Characteristics of Each Pixel after Dual-Bandpass Filter is Inserted) 
       FIG.  11    is a diagram illustrating characteristics of each pixel after the dual-bandpass filter  141  is inserted. Additionally, the characteristics of the pixels illustrated in  FIG.  11    are the characteristics of the pixels after the dual-bandpass filter  141  is inserted, and thus correspond to the characteristics of the pixels  100  illustrated in  FIG.  8   . 
     A of  FIG.  11    illustrates absorption rates of the pixels of the respective color components configured of the organic photoelectric conversion layer  112  in each wavelength band. 
     Here, in a case where the dual-bandpass filter  141  is provided above the color filters  111 , the dual-bandpass filter  141  has a transmission band in a wavelength region (a range of 400 to 650 nm, or the like, for example) of the visible light region, and thus the organic photoelectric conversion layer  112  can absorb lights in the visible light region transmitting through the dual-bandpass filter  141  and the color filters  111 . 
     As illustrated in A of  FIG.  11   , the R pixel  100 - 1 -R can absorb a light (visible light) corresponding to the wavelength region of the R-component light. Further, the G pixel  100 - 2 -G can absorb a light corresponding to the wavelength region of the G-component light, and the B pixel  100 - 3 -B can absorb a light corresponding to the wavelength region of the B-component light. 
     Here, with a comparison between A of  FIG.  10    and A of  FIG.  11   , the dual-bandpass filter  141  has a transmission band in the visible light region, and thus the organic photoelectric conversion layer  112  which absorbs a light in the visible light region can absorb the lights of the respective color components of R component, G component, and B component irrespective of the presence of the inserted dual-bandpass filter  141 . 
     Further, B of  FIG.  11    illustrates transmissivity into the IR pixels configured of the photodiodes  115  arranged below the color filters  111  of the respective color components. 
     Here, in a case where the dual-bandpass filter  141  is provided above the color filters  111 , the dual-bandpass filter  141  has a transmission hand in a wavelength region (a range of 800 to 900 nm, or the like, for example) of the infrared region, and thus only lights (infrared rays) in the wavelength region with the transmission band in the infrared region reach the IR pixel  100 - 1 -IR R , the IR pixel  100 - 2 -IR C , and the IR pixel  100 - 3 -IR B . 
     Then, the IR-component lights detected by (absorbed in) the IR pixel  100 - 1 -IR R , the IR pixel  100 - 2 -IR G , and the IR pixel  100 - 3 -IR B , respectively, correspond to the lights in the wavelength region with the transmission band in the infrared region of the dual-bandpass filter  141 . Thus, as illustrated in B of  FIG.  11   , the spectra of the IR-component lights detected by (absorbed in) the IR pixel  100 - 1 -IR R , the IR pixel  100 - 2 -IR G , and the IR pixel  100 - 3 -IR B  can be uniformed. 
     With a comparison between B of  FIG.  10    and B of  FIG.  11   , in a case where the dual-bandpass filter  141  is not inserted, the spectra of the IR-component lights detected by (absorbed in) the respective IR pixels vary, but the dual-bandpass filter  141  is inserted so that the spectra of the IR-component lights detected by (absorbed in) the respective IR pixels can be uniformed due to the transmission band in the infrared region. Consequently, the sensitivity can be uniformed per IR pixel, and the IR pixels can be used for generating the same IR image. 
     Here, for example, in a case where the pixels  100  illustrated in  FIG.  8    are two-dimensionally arranged in the Bayer layout in the pixel array part  11 , they can be expressed as the respective pixels illustrated in  FIG.  12   . That is, A of  FIG.  12    illustrates an R pixel  100 - 1 -R, G pixels  100 - 2 -G, and a B pixel  100 - 3 -B configured of the organic photoelectric conversion layer  112  ( FIG.  8   ). Further, B of  FIG.  12    illustrates an IR pixel  100 - 1 -IR R , IR pixels  100 - 2 -IR G , and an IR pixel  100 - 3 -IR B  configured of the photodiodes  115  ( FIG.  8   ) embedded in the semiconductor layer  114  below the organic photoelectric conversion layer  112  ( FIG.  8   ). 
     As illustrated in contrasting density of the respective IR pixels in B of  FIG.  12   , the spectra of the IR-component lights detected by (absorbed in) the IR pixel  100 - 1 -IR R , the IR pixels  100 - 2 -IR G , and the IR pixel  100 - 3 -IR B  are the same and the sensitivity of the respective IR pixels are the same. 
     In a case where the structure of the pixels  100  of  FIG.  8    is employed in this way, the lights (visible lights) transmitting through the transmission band in the visible light region of the dual-bandpass filter  141  are absorbed in the R pixel  100 - 1 -R, the G pixel  100 - 2 -G, and the B pixel  100 - 3 -B configured of the organic photoelectric conversion layer  112  as a photoelectric conversion region. On the other hand, the lights (infrared rays) transmitting through the transmission band in the infrared region of the dual-bandpass filter  141  are detected by (absorbed in) the IR pixel  100 - 1 -IR R , the IR pixel  100 - 2 -IR G , and the IR pixel  100 - 3 -IR B  configured of the photodiodes  115 - 1  to  115 - 3  as photoelectric conversion regions. 
     At this time, a light (infrared ray) detected by (absorbed in) each photodiode  115  is a light in the wavelength region with the transmission band in the infrared region of the dual-bandpass filter  141 . Thus, the spectra of the lights detected by (absorbed in) the respective IR pixels are the same. Consequently, an IR image using the IR signals obtained from the IR pixels in all the pixels  100  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) can be acquired and a high-resolution IR image can be acquired. 
     In addition, a plurality of pixels  100  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) are pixels of any color component such as R pixel  100 - 1 -R, G pixel  100 - 2 -G, or B pixel  100 - 3 -B depending on a layout pattern such as Bayer layout, and generates any of R signals, G signals, and B signals. Further, at the same time, all the plurality of pixels  100  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) are IR pixels with the same sensitivity (IR pixel  100 - 1 -IR R , IR pixel  100 - 2 -IR G , or IR pixel  100 - 3 -IR B ), and generates IR signals. 
     As described above, the CMOS image sensor  10  ( FIG.  1   ) having the pixels  100  ( FIG.  8   ) according to the first embodiment can acquire a visible light image using R signals, G signal, or B signals obtained for a plurality of pixels  100  two-dimensionally arranged in a predetermined layout pattern, and a high-resolution IR image using the IR signals obtained from all the plurality of pixels  100  at the same time. 
     Further, at this time, the R pixel  100 - 1 -R, the G pixel  100 - 2 -G, or the B pixel  100 - 3 -B which generates an R signal, a G signal, or a B signal photoelectrically converts a light (visible light) transmitting through the organic photoelectric conversion layer  112  and the color filter  111  formed above the photodiode  115 , and thus can acquire a higher-quality visible light image (can keep image quality of a visible light image in using a conventional Bayer layout, for example) than in a case where an inorganic filter or the like is employed. Consequently, the structure of the pixels  100  according to the first embodiment is employed thereby to generate a high-resolution IR image while keeping high quality of a visible light image. 
     Additionally, the above description has been made by use of the Bayer layout as a layout pattern of a plurality of pixels  100  two-dimensionally arranged in the pixel array part  11  by way of example, but other layout pattern repeated at a predetermined cycle may be employed. Further, though not illustrated, on-chip lenses configured to condense an incident light are actually formed on top of the color filters  111  in the structures of the pixels  100  illustrated in  FIG.  2    and  FIG.  8   . 
     3. Second Embodiment: Structure Using Multilayered Film (OPC: RGB Pixels, PD: IR Pixels) 
     A structure of pixels  200  according to the second embodiment will be described below with reference to  FIG.  13    to  FIG.  17   . 
     (Structure of Pixels) 
       FIG.  13    is a cross-section view illustrating a structure of the pixels  200  according to the second embodiment. 
       FIG.  13    illustrates three pixels  200 - 1  to  200 - 3  arranged at arbitrary positions among a plurality of pixels  200  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ). However, the pixels  200 - 1  to  200 - 3  employ a structure of backside irradiation type. 
     Additionally, color filters  211  to a wiring layer  216 , a transparent electrode  221  to charge holding parts  224 , and wirings  231  in the pixels  200  of  FIG.  13    correspond to the color filters  111  to the wiring layer  116 , the transparent electrode  121  to the charge holding parts  124 , and the wirings  131  in the pixels  100  of  FIG.  2   , respectively. 
     That is, an organic photoelectric conversion layer  212  which absorbs only lights in the visible light region is formed above a semiconductor layer  214  in which photodiodes  215  configured to absorb a light in the infrared region are formed, and color filters  211  are further formed thereon in the pixels  200  of  FIG.  13   . 
     The pixels  200  has the structure illustrated in  FIG.  13   , and thus an R pixel  200 - 1 -R, a G pixel  200 - 2 -G, and a B pixel  200 - 3 -B are configured of the organic photoelectric conversion layer  212 . Further, an IR pixel  200 - 1 -IR R  is configured of a photodiode  215 - 1  in a pixel  200 . Similarly, an IR pixel  200 - 2 -IR G  is configured of a photodiode  215 - 2 , and an IR pixel  200 - 3 -IR B  is configured of a photodiode  215 - 3 . 
     Further, in the pixels  200 , a multilayered filter  241  is formed between the organic photoelectric conversion layer  212  and an interlayer insulative film  213 . The multilayered filter  241  includes an inorganic material, and has a transmission band at least in the infrared region.  FIG.  14    illustrates a cross-section structure of the multilayered filter  241 . 
     In  FIG.  14   , the multilayered filter  241  is formed in a laminated structure of a high refractive index material  241 A which is an inorganic material with a high refractive index and a low refractive index material  241 B which is a material with a low refractive index, for example. The high refractive index material  241 A can employ silicon nitride (Si 3 N 4 ), titanium oxide (TiO 2 ), or the like, for example. Further, the low refractive index material  241 B can employ silicon oxide (SiO) or the like, for example. 
     In  FIG.  14   , the high refractive index material  241 A and the low refractive index material  241 B are periodically and alternately laminated thereby to form the multilayered filter  241 . For example, in the multilayered filter  241 , a transmission band can be determined depending on the thickness of a low refractive index material  241 B formed as an intermediate layer thicker than the other layers. 
     Here,  FIG.  15    illustrates transmissivity of the multilayered filter  241  in each wavelength band. The horizontal axis indicates wavelength (nm) and the vertical axis indicates transmissivity in  FIG.  15   . As illustrated in  FIG.  15   , the multilayered filter  241  has the transmission bands in a wavelength region (a range of 400 to 650 nm, or the like, for example) of the visible light region and in a wavelength region (a range of 800 to 900 nm, or the like, for example) of the infrared region, respectively, and transmits lights with a wavelength included in the transmission bands. 
     The multilayered filter  241  is provided in the pixels  200  so that the spectrum of a light absorbed in each IR pixel can be uniformed for all the IR pixels by the transmission band in the infrared region. A difference in transmissivity into each IR pixel before and after the multilayered filter  241  is inserted will be described here with reference to  FIG.  16    and  FIG.  17   . 
     (Characteristics of Each Pixel Before Multilayered Filter is Inserted) 
       FIG.  16    is a diagram illustrating characteristics of each pixel before the multilayered filter  241  is inserted. Additionally, the characteristics of the pixels illustrated in  FIG.  16    are the characteristics of the pixels before the multilayered filter  241  is inserted, and thus correspond to the characteristics of the pixels  100  illustrated in  FIG.  2   . 
     A of  FIG.  16    illustrates absorption rates of pixels of each color component configured of the organic photoelectric conversion layer  212  in each wavelength band. As illustrated in A of  FIG.  16   , the R pixel  200 - 1 -R can absorb a light (visible light) corresponding to the wavelength region of the R-component light. Further, the G pixel  200 - 2 -G can absorb a light corresponding to the wavelength region of the G-component light, and the B pixel  200 - 3 -B can absorb a light corresponding to the wavelength region of the B-component light. 
     Further, B of  FIG.  16    illustrates transmissivity into the IR pixels arranged below the color filters  211  of the respective color components. As illustrated in B of  FIG.  16   , the spectra of the IR-component lights absorbed in the IR pixel  200 - 1 -IR R , the IR pixel  200 - 2 -IR G , and the IR pixel  200 - 3 -IR B  are different. That is, as described above, the IR pixels are different in sensitivity per IR pixel, and thus the IR pixels cannot be used to generate the same IR image. 
     (Characteristics of Each Pixel after Multilayered Filter is Inserted) 
       FIG.  17    is a diagram illustrating characteristics of each pixel after the multilayered filter  241  is inserted. Additionally, the characteristics of the pixels illustrated in  FIG.  17    are the characteristics of the pixels after the multilayered filter  241  is inserted, and thus correspond to the characteristics of the pixels  200  illustrated in  FIG.  13   . 
     A of  FIG.  17    illustrates absorption rates of pixels of each color component configured of the organic photoelectric conversion layer  212  in each wavelength band. The multilayered filter  241  is formed below the organic photoelectric conversion layer  212  in the pixels  200  so that the lights absorbed in the R pixel  200 - 1 -R, the G pixel  200 - 2 -G, and the B pixel  200 - 3 -B do not change before and after the multilayered filter  241  is inserted. That is, the waveforms of the absorption rates of the R, G, and B pixels illustrated in A of  FIG.  16    are the same as the waveforms of the absorption rates of the R, G, and B pixels illustrated in A of  FIG.  17   . 
     Further, B of  FIG.  17    illustrates transmissivity into the IR pixels arranged below the color filters  211  of the respective color components. 
     Here, in a case where the multilayered filter  241  is provided below the organic photoelectric conversion layer  212 , the multilayered filter  241  has a transmission band in a wavelength region (a range of 800 to 900 nm, or the like, for example) of the infrared region, and thus only lights (infrared rays) in the wavelength region with the transmission band in the infrared region reach the IR pixel  200 - 1 -IR R , the IR pixel  200 - 2 -IR G , and the IR pixel  200 - 3 -IR B . 
     In addition, the IR-component lights absorbed in the IR pixel  200 - 1 -IR R , the IR pixel  200 - 2 -IR G , and the IR pixel  200 - 3 -IR B , respectively, correspond to the lights in the wavelength region with the transmission band in the infrared region of the multilayered filter  241 . Thus, as illustrated in B of  FIG.  17   , the spectra of the IR-component lights detected by the IR pixel  200 - 1 -IR R , the IR pixel  200 - 2 -IR G , and the IR pixel  200 - 3 -IR B , respectively, can be uniformed. 
     With a comparison between B of  FIG.  16    and B of  FIG.  17   , in a case where the multilayered filter  241  is not inserted, the spectra of the IR-component lights absorbed in the respective IR pixels vary, but the multilayered filter  241  is inserted so that the spectra of the IR-component lights absorbed in the respective IR pixels can be uniformed by the transmission band in the infrared region. Consequently, the sensitivity per IR pixel can be uniformed, and the IR pixels can be used to generate the same IR image. 
     Additionally, the description has been made assuming that the multilayered filter  241  is characterized in that the transmission bands are provided in both the visible light region and the infrared region in  FIG.  15   , but a transmission band may be provided only in the infrared region. That is, the multilayered filter  241  is provided below the organic photoelectric conversion layer  212  in the pixels  200  so that the lights in the visible light region are sufficiently absorbed in the organic photoelectric conversion layer  212 . Thus, if a transmission band is not provided in the visible light region in the multilayered filter  241  below the organic photoelectric conversion layer  212 , a light in the visible light region does not have an effect on the photodiodes  215  below the multilayered filter  241 . 
     Further, the multilayered filter  241  may be characterized in that a transmission band is provided in the infrared region and a light in the visible light region can be reflected. In this case, in a case where a light in the visible light region which cannot be absorbed in the organic photoelectric conversion layer  212  reaches the multilayered filter  241 , the light in the visible light region can reflect toward the organic photoelectric conversion layer  212  by the multilayered filter  241 . 
     Consequently, the organic photoelectric conversion layer  212  can absorb not only lights in the visible light region above it but also lights in the visible light region from the multilayered filter  241  below it, and thus the amount of absorbed light in the visible light region can be increased in the organic photoelectric conversion layer  212 . Further, the organic photoelectric conversion layer  212  can increase the amount of absorbed light in the visible light region, and thus can decrease the thickness thereof. 
     In a case where the structure of the pixels  200  of  FIG.  13    is employed in this way, lights (visible lights) transmitting through the respective color filters  211  are absorbed in the R pixel  200 - 1 -R, the G pixel  200 - 2 -G, and the B pixel  200 - 3 -B configured of the organic photoelectric conversion layer  212  as a photoelectric conversion region. On the other hand, lights (infrared rays) transmitting through the transmission band in the infrared region of the multilayered filter  241  are absorbed in the IR pixel  200 - 1 -IR R , the IR pixel  200 - 2 -IR R , and the IR pixel  200 - 3 -IR B  configured of the photodiodes  215 - 1  to  215 - 3  as photoelectric conversion regions. 
     At this time, a light (infrared ray) absorbed in each photodiode  215  is a light in the wavelength region with the transmission band in the infrared region of the multilayered filter  241 . Thus, the spectra of the lights absorbed in the respective IR pixels are uniformed. Consequently, an IR image using the IR signals obtained from the IR pixels in all the pixels  200  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) can be acquired, and a high-resolution IR image can be acquired. 
     Then, a plurality of pixels  200  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) are pixels of any color component such as R pixel  200 - 1 -R, G pixel  200 - 2 -G, or B pixel  200 - 3 -B depending on a layout pattern such as Bayer layout, thereby generating any of R signals, G signals, and B signals. Further, at the same time, all the plurality of pixels  200  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) are IR pixels with the same sensitivity (IR pixel  200 - 1 -IR R , IR pixel  200 - 2 -IR G , or IR pixel  200 - 3 -IR B ) thereby to generate IR signals. 
     As described above, the CMOS image sensor  10  ( FIG.  1   ) having the pixels  200  ( FIG.  13   ) according to the second embodiment can acquire a visible light image using R signals, G signals, or B signals obtained for a plurality of pixels  200  two-dimensionally arranged in a predetermined layout pattern, and a high-resolution IR image using the IR signals obtained from all the plurality of pixels  200  at the same time. 
     Further, at this time, the R pixel  200 - 1 -R, the G pixel  200 - 2 -G, or the B pixel  200 - 3 -B which generates an R signal, a G signal, or a B signal photoelectrically converts a light (visible light) transmitting through the organic photoelectric conversion layer  212  and the color filter  211  formed above the photodiode  215 , thereby acquiring a high-quality visible light image. Consequently, the structure of the pixels  200  according to the second embodiment is employed thereby to generate a high-resolution IR image while keeping high quality of a visible light image. 
     4. Third Embodiment: Structure Using Plasmon Filter (OPC: RGB Pixels, PD: IR Pixels) 
     A structure of pixels  300  according to the third embodiment will be described below with reference to  FIG.  18    and  FIG.  19   . 
     (Structure of Pixels) 
       FIG.  18    is a cross-section view illustrating a structure of the pixels  300  according to the third embodiment. 
       FIG.  18    illustrates three pixels  300 - 1  to  300 - 3  arranged at arbitrary positions among a plurality of pixels  300  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) by way of example. However, the pixels  300 - 1  to  300 - 3  employ a structure of backside irradiation type. 
     Additionally, color filters  311  to a wiring layer  316 , a transparent electrode  321  to charge holding parts  324 , and wirings  331  in the pixels  300  of  FIG.  18    correspond to the color filters  111  to the wiring layer  116 , the transparent electrode  121  to the charge holding parts  124 , and the wirings  131  in the pixels  100  of  FIG.  2   , respectively. 
     That is, in the pixels  300  of  FIG.  18   , an organic photoelectric conversion layer  312  configured to absorb only lights in the visible light region is formed above a semiconductor layer  314  in which photodiodes  315  as photoelectric conversion regions are formed, and the color filters  311  are further formed thereon. 
     The pixels  300  employ the structure illustrated in  FIG.  18    so that an R pixel  300 - 1 -R, a G pixel  300 - 2 -G, and a B pixel  300 - 3 -B are configured of the organic photoelectric conversion layer  312 . Further, an IR pixel  300 - 1 -IR R  is configured of a photodiode  315 - 1  in a pixel  300 . Similarly, an IR pixel  300 - 2 -IR G  is configured of a photodiode  315 - 2  and an IR pixel  300 - 3 -IR B  is configured of a photodiode  315 - 3 . 
     Further, a plasmon filter  341  is formed between the organic photoelectric conversion layer  312  and the semiconductor layer  314  in the pixels  300 . The plasmon filter  341  is a metal thin-film filter using surface plasmon polariton (SPP), and has a transmission band at least in the infrared region.  FIG.  19    illustrates a structure of the plasmon filter  341 . 
     In  FIG.  19   , the plasmon filter  341  is configured in which holes  341 B having an opening with a predetermined diameter are arranged for a metal thin-film  341 A in a honeycomb structure. The metal thin-film  341 A includes a metal such as aluminum (Al), gold (Au), or silver (Ag), an alloy, or the like, for example. Further, the diameter of the opening of the hole  341 B is as large as a photodiode  315  formed in the semiconductor layer  314  can detect a light within a certain wavelength region in the infrared region. Additionally, a material such as silicon nitride (SiN) can be embedded inside the holes  341 B. 
     Additionally, the arrangement of the holes  341 B in the plasmon filter  341  is not limited to the honeycomb structure illustrated in  FIG.  19   , but may be any periodic arrangement such as arrangement having an orthogonal matrix (square matrix) structure, and the like. Further, the microstructural pattern of the plasmon filter  341  may be a ring-shaped, dot-shaped pattern, or the like, for example, in addition to a structure in which the holes  341 B are arranged illustrated in  FIG.  19   . That is, the plasmon filter  341  can be a metal thin-film filter in which at least one periodic microstructural pattern is formed for the metal thin-film. 
     In a case where the structure of the pixels  300  of  FIG.  18    is employed in this way, lights (visible lights) transmitting through the respective color filters  311  are absorbed in the R pixel  300 - 1 -R, the G pixel  300 - 2 -G, and the B pixel  300 - 3 -B configured of the organic photoelectric conversion layer  312  as a photoelectric conversion region. On the other hand, lights (infrared rays) transmitting through the plasmon filter  341  are absorbed in the IR pixel  300 - 1 -IR R , the IR pixel  300 - 2 -IR G , and the IR pixel  300 - 3 -IR B  configured of the photodiodes  315 - 1  to  315 - 3  as photoelectric conversion regions, respectively. 
     At this time, a light (infrared ray) absorbed in each IR pixel configure of each photodiode  315  is a light in a certain wavelength region in the infrared region transmitting through the plasmon filter  341 . Thus, the spectra of the lights absorbed in the respective IR pixels are the same. Consequently, an IR image using the IR signals obtained from the IR pixels in all the pixels  300  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) can be acquired, and a high-resolution IR image can be acquired. 
     Then, a plurality of pixels  300  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) are pixels of any color component such as R pixel  300 - 1 -R, G pixel  300 - 2 -G, or B pixel  300 - 3 -B depending on a layout pattern such as Bayer layout thereby to generate any of R signals, G signals, and B signals. Further, at the same time, all the plurality of pixels  300  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) are IR pixels with the same sensitivity (IR pixel  300 - 1 -IR R , IR pixel  300 - 2 -IR G , or IR pixel  300 - 3 -IR B ) thereby to generate IR signals. 
     As described above, the CMOS image sensor  10  ( FIG.  1   ) having the pixels  300  (FIG.  18 ) according to the third embodiment can acquire a visible light image using R signals, G signals, or B signals obtained for a plurality of pixels  300  two-dimensionally arranged in a predetermined layout pattern and a high-resolution IR image using the IR signals obtained from all the plurality of pixels  300  at the same time. 
     Further, at this time, the R pixel  300 - 1 -R, the G pixel  300 - 2 -G, or the B pixel  300 - 3 -B configured to generate an R signal, a G signal, or a B signal photoelectrically converts a light (visible light) transmitting through the organic photoelectric conversion layer  312  and the color filter  311  formed above the photodiode  315 , thereby acquiring a high-quality visible light image. Consequently, the structure of the pixels  300  according to the third embodiment is employed thereby to generate a high-resolution IR image while keeping high quality of a visible light image. 
     Additionally, the plasmon filter  341  is employed as a filter having a transmission band at least in the infrared region according to the third embodiment, and is advantageous in that the manufacturing steps are easier than in a case where the multilayered filter  241  having the similar characteristics is employed. That is, in a case where the multilayered filter  241  is employed, a step of manufacturing a multilayered film with different refractive indexes is required on manufacture, while the step is not required on manufacture in a case where the plasmon filter  341  is employed, and thus the manufacturing steps are easier in terms of the point. 
     5. Fourth Embodiment: Structure Using Dual-Bandpass Filter (OPC: IR Pixels, PD: RGB Pixels) 
     A structure of pixels  400  according to the fourth embodiment will be described below with reference to  FIG.  20    to  FIG.  23   . 
     (Structure of Pixels) 
       FIG.  20    is a cross-section view illustrating a structure of the pixels  400  according to the fourth embodiment. 
       FIG.  20    illustrates three pixels  400 - 1  to  400 - 3  arranged at arbitrary positions among a plurality of pixels  400  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) by way of example. However, the pixels  400 - 1  to  400 - 3  employ a structure of backside irradiation type. 
     Additionally, color filters  411  to a wiring layer  416 , a transparent electrode  421  to charge holding parts  424 , and wirings  431  in the pixels  400  of  FIG.  20    correspond to the color filters  111  to the wiring layer  116 , the transparent electrode  121  to the charge holding parts  124 , and the wirings  131  in the pixels  100  of  FIG.  2   , respectively. 
     That is, in the pixels  400  of  FIG.  20   , an organic photoelectric conversion layer  412  configured to absorb only lights in the infrared region is formed above a semiconductor layer  414  in which photodiodes  415  as photoelectric conversion regions are formed, and the color filters  411  are further formed thereon. Additionally, a photoelectric conversion material in the infrared region of the organic photoelectric conversion layer  412  can employ a bulk-hetero structure in a combination of chloroaluminum phthalocyanine (ClAlPc) absorbent in the infrared region and transparent organic semiconductor, for example. 
     The pixels  400  have the structure illustrated in  FIG.  20   , and thus an IR pixel  400 - 1 -IR R , an IR pixel  400 - 2 -IR G , and an IR pixel  400 - 3 -IR B  are configured of the organic photoelectric conversion layer  412 . Further, in the pixels  400 , an R pixel  400 - 1 -R is configured of a photodiode  415 - 1 . Similarly, a G pixel  400 - 2 -G is configured of a photodiode  415 - 2 , and a B pixel  400 - 3 -B is configured of a photodiode  415 - 3 . 
     Further, in the pixels  400 , a dual-bandpass filter  441  is formed above the color filters  411 . The dual-bandpass filter  441  has transmission bands in the visible light region and in the infrared region, respectively, similarly to the dual-bandpass filter  141  of  FIG.  8   . As illustrated in  FIG.  21   , the dual-bandpass filter  441  has the transmission bands in a wavelength region (a range of 400 to 650 nm, or the like, for example) of the visible light region and in a wavelength region (a range of 800 to 900 nm, or the like, for example) of the infrared region, respectively. 
     The dual-bandpass filter  441  is provided in the pixels  400  so that the spectrum of a light absorbed in each IR pixel can be the same for all the IR pixels due to the transmission band in the infrared region. A difference in transmissivity into each IR pixel before and after the dual-bandpass filter  441  is inserted will be described here with reference to  FIG.  22    and  FIG.  23   . 
     (Characteristics of Each Pixel Before Dual-Bandpass Filter is Inserted) 
       FIG.  22    is a diagram for explaining characteristics of each pixel before the dual-bandpass filter  441  is inserted. 
     A of  FIG.  22    illustrates an absorption rate of the organic photoelectric conversion layer  412  in each wavelength band. As illustrated in A of  FIG.  22   , the organic photoelectric conversion layer  412  absorbs lights (infrared rays) corresponding to a wavelength region (wavelength region with a certain width) of an IR-component light, and thus infrared rays in the wavelength region with a certain width are absorbed in the IR pixel  400 - 1 -IR R , the IR pixel  400 - 2 -IR G , and the IR pixel  400 - 3 -IR B . 
     Further, B of  FIG.  22    illustrates transmissivity of the color filters  411  of the respective color components in each wavelength band. The transmissivity into the R, G, and B pixels configured of the photodiodes  415  arranged below the color filters  411  corresponds to the lights transmitting through the color filters  411  having the characteristics of B of  FIG.  22    and the organic photoelectric conversion layer  412  having the characteristics of A of  FIG.  22   . The transmitted lights (visible lights) are then absorbed in the R pixel  400 - 1 -R, the G pixel  400 - 2 -G, and the B pixel  400 - 3 -B. 
     (Characteristics of Each Pixel after Dual-Bandpass Filter is Inserted) 
       FIG.  23    is a diagram illustrating characteristics of each pixel after the dual-bandpass filter  441  is inserted. Additionally, the characteristics of the pixels illustrated in  FIG.  23    are the characteristics of the pixels after the dual-bandpass filter  441  is inserted, and thus correspond to the characteristics of the pixels  400  illustrated in  FIG.  20   . 
     A of  FIG.  23    illustrates an absorption rate of the IR pixels configured of the organic photoelectric conversion layer  412  in each wavelength band. 
     Here, in a case where the dual-bandpass filter  441  is provided above the color filters  411 , the dual-bandpass filter  441  has a transmission band in a wavelength region (a range of 800 to 900 nm, or the like, for example) of the infrared region, and thus only lights (infrared rays) in the wavelength region with the transmission band in the infrared region are absorbed in the IR pixel  400 - 1 -IR R , the IR pixel  400 - 2 -IR G , and the IR pixel  400 - 3 -IR B . 
     Further, B of  FIG.  23    illustrates transmissivity into the R, G, and B pixels configured of the photodiodes  415  arranged below the color filters  411  of the respective color components. 
     Here, in a case where the dual-bandpass filter  441  is provided above the color filters  411 , the dual-bandpass filter  441  has a transmission band in a wavelength region (a range of 400 to 650 nm, or the like, for example) of the visible light region, and thus lights (visible lights) transmitting through the dual-bandpass filter  441  and the organic photoelectric conversion layer  412  are absorbed in the R pixel  400 - 1 -R, the G pixel  400 - 2 -G, and the B pixel  400 - 3 -B. 
     As illustrated in B of  FIG.  23   , the R pixel  400 - 1 -R can absorb a light (visible light) corresponding to the wavelength region of the R-component light. Further, the G pixel  400 - 2 -G can absorb a light corresponding to the wavelength region of the G-component light, and the B pixel  400 - 3 -B can absorb a light corresponding to the wavelength region of the B-component light. 
     In a case where the structure of the pixels  400  of  FIG.  20    is employed in this way, lights (infrared rays) transmitting through the transmission band in the infrared region of the dual-bandpass filter  441  are absorbed in the IR pixel  400 - 1 -IR R , the IR pixel  400 - 2 -IR G , and the IR pixel  400 - 3 -IR B  configured of the organic photoelectric conversion layer  412  as a photoelectric conversion region. On the other hand, lights (visible lights) transmitting through the transmission band in the visible light region of the dual-bandpass filter  441  are absorbed in the R pixel  400 - 1 -R, the G pixel  400 - 2 -G, and the B pixel  400 - 3 -B configured of the photodiodes  415 - 1  to  415 - 3  as photoelectric conversion regions. 
     At this time, a light (infrared ray) absorbed in each IR pixel configured of the organic photoelectric conversion layer  412  is a light in the wavelength region with the transmission band in the infrared region of the dual-bandpass filter  441 . Thus, the spectra of the lights absorbed in the respective IR pixels are the same. Consequently, an IR image using the IR signals obtained from the IR pixels in all the pixels  400  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) can be acquired, and a high-resolution IR image can be acquired. 
     A plurality of pixels  400  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) are then pixels of any color component such as R pixel  400 - 1 -R, G pixel  400 - 2 -G, or B pixel  400 - 3 -B depending on a layout pattern such as Bayer layout thereby to generate any of R signals, G signal, and B signals. Further, at the same time, all the plurality of pixels  400  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) are IR pixels with the same sensitivity (IR pixel  400 - 1 -IR R , IR pixel  400 - 2 -IR G , or IR pixel  400 - 3 -IR B ) thereby to generate IR signals. 
     As described above, the CMOS image sensor  10  ( FIG.  1   ) having the pixels  400  ( FIG.  20   ) according to the fourth embodiment can acquire a visible light image using R signals, G signals, or B signals obtained for a plurality of pixels  400  two-dimensionally arranged in a predetermined layout pattern, and a high-resolution IR image using the IR signals obtained from all the plurality of pixels  400  at the same time. 
     Further, at this time, the R pixel  400 - 1 -R, the G pixel  400 - 2 -G, or the B pixel  400 - 3 -B which generates an R signal, a G signal, or a B signal photoelectrically converts a light (visible light) transmitting through the organic photoelectric conversion layer  412  and the color filter  411  formed above the photodiode  415 , thereby acquiring a high-quality visible light image. Consequently, the structure of the pixels  400  according to the fourth embodiment is employed thereby to generate a high-resolution IR image while keeping high quality of a visible light image. 
     6. Fifth Embodiment: Structure Using Multilayered Filter (OPC: IR Pixels, PD: RGB Pixels) 
     A structure of pixels  500  according to the fifth embodiment will be finally described with reference to  FIG.  24    and  FIG.  25   . 
     (Structure of Pixels) 
       FIG.  24    is a cross-section view illustrating a structure of the pixels  500  according to the fifth embodiment. 
       FIG.  24    illustrates three pixels  500 - 1  to  500 - 3  arranged at arbitrary positions among a plurality of pixels  500  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) by way of example. However, the pixels  500 - 1  to  500 - 3  employ a structure of backside irradiation type. 
     Additionally, color filters  511  to a wiring layer  516 , a transparent electrode  521  to charge holding parts  524 , and wirings  531  in the pixels  500  of  FIG.  24    correspond to the color filters  111  to the wiring layer  116 , the transparent electrode  121  to the charge holding parts  124 , and the wirings  131  in the pixels  100  of  FIG.  2   , respectively. 
     That is, in the pixels  500  of  FIG.  24   , an organic photoelectric conversion layer  512  which absorbs only lights in the infrared regions is formed above a semiconductor layer  514  in which photodiodes  515  as photoelectric conversion regions are formed, and the color filters  511  are further formed thereon. Additionally, a photoelectric conversion material of the infrared region of the organic photoelectric conversion layer  512  can employ a bulk-hetero structure similarly to the organic photoelectric conversion layer  412  of  FIG.  20   . 
     The pixels  500  have the structure illustrated in  FIG.  24   , and thus an IR pixel  500 - 1 -IR R , an IR pixel  500 - 2 -IR G , and an IR pixel  500 - 3 -IR B  are configured of the organic photoelectric conversion layer  512 . Further, in the pixels  500 , an R pixel  500 - 1 -R is configured of a photodiode  515 - 1 . Similarly, a G pixel  500 - 2 -G is configured of a photodiode  515 - 2 , and a B pixel  500 - 3 -B is configured of a photodiode  515 - 3 . 
     Further, a multilayered filter  541  is formed between the color filters  511  and the organic photoelectric conversion layer  512  in the pixels  500 . The multilayered filter  541  has transmission bands in the visible light region and the infrared region, respectively, similarly to the multilayered filter  241  of  FIG.  13   . As illustrated in  FIG.  25   , the multilayered filter  541  has the transmission bands in a wavelength region (a range of 400 to 650 nm, or the like, for example) of the visible light region and in a wavelength region (a range of 800 to 900 nm, or the like, for example) of the infrared region, respectively. 
     In a case where the structure of the pixels  500  of  FIG.  24    is employed in this way, lights (infrared rays) transmitting through the transmission band in the infrared region of the multilayered filter  541  are absorbed in the IR pixel  500 - 1 -IR R , the IR pixel  500 - 2 -IR R , and the IR pixel  500 - 3 -IR B  configured of the organic photoelectric conversion layer  512  as a photoelectric conversion region. On the other hand, lights (visible lights) transmitting through the transmission band in the visible light region of the multilayered filter  541  are absorbed in the R pixel  500 - 1 -R, the G pixel  500 - 2 -G, and the B pixel  500 - 3 -B configured of the photodiodes  515 - 1  to  515 - 3  as photoelectric conversion regions, respectively. 
     At this time, a light (infrared ray) absorbed in each IR pixel configured of the organic photoelectric conversion layer  512  is a light in the wavelength region with the transmission band in the infrared region of the multilayered filter  541 . Thus, the spectra of the lights absorbed in the respective IR pixels are the same. Consequently, an IR image using the IR signals obtained from the IR pixels in all the pixels  500  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) can be acquired, and a high-resolution IR image can be acquired. 
     A plurality of pixels  500  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) are then pixels of any color component such as R pixel  500 - 1 -R, G pixel  500 - 2 -G, or B pixel  500 - 3 -B depending on a layout pattern such as Bayer layout thereby to generate any of R signals, G signals, and B signals. Further, at the same time, all the plurality of pixels  500  two-dimensionally arranged in the pixel array part  11  ( FIG.  1   ) are IR pixels with the same sensitivity (IR pixel  500 - 1 -IR R , IR pixel  500 - 2 -IR G , or IR pixel  500 - 3 -IR B ) thereby to generate IR signals. 
     As described above, the CMOS image sensor  10  ( FIG.  1   ) having the pixels  500  ( FIG.  24   ) according to the fifth embodiment can acquire a visible light image using R signals, G signals, or B signals obtained for a plurality of pixels  500  two-dimensionally arranged in a predetermined layout pattern, and a high-resolution IR image using the IR signals obtained from all the plurality of pixels  500  at the same time. 
     Further, at this time, the R pixel  500 - 1 -R, the G pixel  500 - 2 -G, or the B pixel  500 - 3 -B which generates an R signal, a G signal, or a B signal photoelectrically converts a light (visible light) transmitting through the organic photoelectric conversion layer  512  and the color filter  511  formed above the photodiode  515  thereby to acquire a high-quality visible light image. Consequently, the structure of the pixels  500  according to the fifth embodiment is employed thereby to generate a high-resolution IR image while keeping high quality of a visible light image. 
     7. Readout Circuit 
     A readout circuit in a pixel according to the first embodiment to the fifth embodiment will be described below with reference to  FIG.  26    and  FIG.  27   . A circuit for reading out signal charges obtained by the organic photoelectric conversion layer  112  and a circuit for reading out signal charges obtained by the photodiode  115  in a pixel  100  ( FIG.  8   ) according to the first embodiment will be described here by way of example. 
     However, a readout circuit for the organic photoelectric conversion layer  112  employs a system in which a memory part is provided for reducing noises and a system in which a feedback amplifier is provided to feed back a signal. A readout circuit employing the latter feedback system will be described here. 
     (Readout Circuit for Organic Photoelectric Conversion Layer) 
       FIG.  26    is a diagram illustrating a readout circuit for the organic photoelectric conversion layer  112  in a pixel  100  ( FIG.  8   ). 
     In  FIG.  26   , a pixel  100  has a pixel circuit (readout circuit) configured of a FD part  171 , a reset transistor  172 , an amplification transistor  173 , and a select transistor  174  in addition to the organic photoelectric conversion layer  112 . The pixel  100  is further provided with a feedback amplifier  175  for feeding back a readout signal to a reset signal for the pixel circuit. 
     Further, a plurality of drive lines as pixel drive lines  21  ( FIG.  1   ) are wired per row of pixels, for example, for the pixels  100 . Various drive signals SEL and RST are then supplied via a plurality of drive lines from the vertical drive circuit  12  ( FIG.  1   ). 
     The organic photoelectric conversion layer  112  is a photoelectric conversion region which absorbs only lights in the visible light region and generates signal charges (charges) corresponding to a light of each color component such as R component, G component, or B component. 
     The FD part  171  is connected between the organic photoelectric conversion layer  112  and the amplification transistor  173 . The FD part  171  is floating diffusion (FD), charge/voltage-converts signal charges generated by the organic photoelectric conversion layer  112  into a voltage signal, and outputs the voltage signal to the amplification transistor  173 . 
     The amplification transistor  173  is connected at its gate electrode to the FD part  171 , is connected at its drain electrode to the power supply part, and serves as an input part of a circuit for reading out a voltage signal held in the FD part  171  or a source follower circuit. That is, the amplification transistor  173  is connected at its source electrode to a vertical signal line  22  ( FIG.  1   ) via the select transistor  174  thereby to configure a constant current source connected to one end of the vertical signal line  22 , and a source follower circuit. 
     The select transistor  174  is connected between the source electrode of the amplification transistor  173  and the vertical signal line  22  ( FIG.  1   ). A drive signal SEL is applied to the gate electrode of the select transistor  174 . When the drive signal SEL enters the active state, the select transistor  174  enters the conducted state and the pixel  100  is in the selected state. With this arrangement, a readout signal (pixel signal) output from the amplification transistor  173  is output to the vertical signal line  22  ( FIG.  1   ) via the select transistor  174 . 
     The reset transistor  172  is connected between the FD part  171  and the power supply part. A drive signal RST is applied to the gate electrode of the reset transistor  172 . When the drive signal RST enters the active state, the reset gate of the reset transistor  172  enters the conducted state and a reset signal for resetting the FD part  171  is supplied to the FD part  171 . 
     The feedback amplifier  175  is connected at one input terminal (−) to the vertical signal line  22  connected to the select transistor  174 , and is connected at the other input terminal (+) to a reference voltage part (Vref). Further, the output terminal of the feedback amplifier  175  is connected between the reset transistor  172  and the power supply part. The feedback amplifier  175  feeds back a readout signal (pixel signal) from the pixel  100  to a reset signal by the reset transistor  172 . 
     Specifically, in a case where the reset transistor  172  resets the FD part  171 , the drive signal RST enters the active state and the reset gate enters the conducted state. At this time, the feedback amplifier  175  gives a necessary gain to and feeds back an output signal of the select transistor  174  and feeds back thereby to cancel noises at the input part of the amplification transistor  173 . 
     The readout circuit for the organic photoelectric conversion layer  112  in the pixel  100  is configured as described above. 
     Additionally,  FIG.  26    illustrates the readout circuit for the organic photoelectric conversion layer  112  in the pixel  100  ( FIG.  8   ) according to the first embodiment by way of example, but a readout circuit for the organic photoelectric conversion layers  212  to  512  can be configured similarly also in a pixel  200  to a pixel  500  according to the other embodiments. However, according to the fourth embodiment or the fifth embodiment, the organic photoelectric conversion layer  412  or  512  absorbs only lights in the infrared region and generates signal charges. 
     (Readout Circuit for Photodiode) 
       FIG.  27    is a diagram illustrating a readout circuit for a photodiode  115  in a pixel  100  ( FIG.  8   ). 
     In  FIG.  27   , a pixel  100  has a pixel circuit (readout circuit) configured of a transfer transistor  181 , a FD part  182 , a reset transistor  183 , an amplification transistor  184 , and a select transistor  185  in addition to the photodiode  115 . Further, a plurality of drive lines as pixel drive lines  21  ( FIG.  1   ) are wired per row of pixels, for example, in the pixels  100 . Various drive signals TG, SEL, and RST are then supplied via a plurality of drive lines from the vertical drive circuit  12  ( FIG.  1   ). 
     The photodiode  115  is a photoelectric conversion region including a pn-junction photodiode, for example. The photodiode  115  generates and accumulates signal charges (charges) depending on the amount of received light. 
     The transfer transistor  181  is connected between the photodiode  115  and the FD part  182 . A drive signal TG is applied to the gate electrode of the transfer transistor  181 . When the drive signal TG enters the active state, the transfer gate of the transfer transistor  181  enters the conducted state, and the signal charges accumulated in the photodiode  115  are transferred to the FD part  182  via the transfer transistor  181 . 
     The FD part  182  is connected between the transfer transistor  181  and the amplification transistor  184 . The FD part  182  is floating diffusion (FD), charge/voltage-converts the signal charges transferred by the transfer transistor  181  into a voltage signal, and outputs the voltage signal to the amplification transistor  184 . 
     The reset transistor  183  is connected between the FD part  182  and the power supply part. A drive signal RST is applied to the gate electrode of the reset transistor  183 . When the drive signal RST enters the active state, the reset gate of the reset transistor  183  enters the conducted state, and the potential of the FD part  182  is reset at a level of the power supply part. 
     The amplification transistor  184  is connected at its gate electrode to the FD part  182 , is connected at its drain electrode to the power supply part, and serves as an input part of a circuit for reading out a voltage signal held in the FD part  182  or a source follower circuit. That is, the amplification transistor  184  is connected at its source electrode to the vertical signal line  22  ( FIG.  1   ) via the select transistor  185  thereby to configure a constant current source connected to one end of the vertical signal line  22 , and a source follower circuit. 
     The select transistor  185  is connected between the source electrode of the amplification transistor  184  and the vertical signal line  22  ( FIG.  1   ). A drive signal SEL is applied to the gate electrode of the select transistor  185 . When the drive signal SEL enters the active state, the select transistor  185  enters the conducted state and the pixel  100  is in the selected state. With this arrangement, a readout signal (pixel signal) output from the amplification transistor  184  is output to the vertical signal line  22  ( FIG.  1   ) via the select transistor  185 . 
     The readout circuit for the photodiode  115  in the pixel  100  is configured as described above. 
     Additionally,  FIG.  27    illustrates the readout circuit for the photodiode  115  in the pixel  100  ( FIG.  8   ) according to the first embodiment by way of example, but a readout circuit for the photodiodes  215  to  515  can be configured similarly also in a pixel  200  to a pixel  500  according to the other embodiments. However, according to the first embodiment to the third embodiment, the photodiodes  115  to  315  are IR pixels. Further, according to the fourth embodiment and the fifth embodiment, the photodiodes  415  to  515  are pixels corresponding to each color component. 
     The readout circuits in a pixel according to the first embodiment to the fifth embodiment have been described above, but in a case where the readout circuit for the organic photoelectric conversion layer employs the feedback system as illustrated in  FIG.  26   , a memory part does not need to be provided, but the feedback system is disadvantageous in readout speed and is characterized in that reset noises (kTC noises) cannot be completely removed. 
     On the other hand, a limited readout speed or reset noises may be further permitted in generating an IR image than in generating a visible light image. For example, a light (IR light) in the infrared region is applied on an object by use of an external IR light source in generating an IR image thereby to secure sufficient sensitivity, and thus the problem is eliminated even if reset noises cannot be completely removed. Further, limited fast readout may be permitted depending on an application of an IR image. 
     With this arrangement, in a case where the organic photoelectric conversion layer absorbs only lights in the infrared region and generates signal charges, a readout circuit for the organic photoelectric conversion layer can employ the readout circuit in the feedback system illustrated in  FIG.  26   . In this case, a readout circuit for a photodiode employs the readout circuit illustrated in  FIG.  27    thereby to read out RGB signals at a high speed and at low noises. 
     That is, a combination of the readout circuit for the organic photoelectric conversion layer illustrated in  FIG.  26    and the readout circuit for the photodiode illustrated in  FIG.  27    is preferably applied to pixels in which IR pixels are configured of an organic photoelectric conversion layer and RGB pixels are configured of photodiodes. Thus, the pixels  400  according to the fourth embodiment and the pixels  500  according to the fifth embodiment among the pixels according to the first embodiment to the fifth embodiment have the structure suitable for the combination of the readout circuits illustrated in  FIG.  26    and  FIG.  27   . 
     However, the combination of the readout circuits illustrated in  FIG.  26    and  FIG.  27    is exemplary, and, for example, a readout circuit for an organic photoelectric conversion layer which absorbs only lights in the visible light region in the pixels  100  to  300  according to the first embodiment to the third embodiment employs a readout circuit provided with a memory part for reducing noises, for example, thereby reading out RGB signals at low noises. Additionally, the readout circuit for the organic photoelectric conversion layer illustrated in  FIG.  26    may be of course employed for the pixels  100  to  300  according to the first embodiment to the third embodiment. 
     That is, the combination of the readout circuits illustrated in  FIG.  26    and  FIG.  27    is exemplary, and any combination of a readout circuit capable of reading out signal charges photoelectrically converted by an organic photoelectric conversion layer and a readout circuit capable of reading out signal charges photoelectrically converted by a photodiode may be employed. Additionally, a readout circuit for an organic photoelectric conversion layer may be the same as a readout circuit for a photodiode. 
     8. Variant 
     (Other Structure of Pixels) 
     The description has been made assuming that the pixels according to the first embodiment to the fifth embodiment are in a structure of backside irradiation type, but a structure of surface irradiation type may be employed.  FIG.  28    illustrates that the pixels  100  ( FIG.  8   ) according to the first embodiment are in a structure of surface irradiation type. The wiring layer  116  is formed on the semiconductor layer  114  in the pixels  100  of surface irradiation type in  FIG.  28   . 
     Similarly,  FIG.  29    to  FIG.  32    illustrate that the pixels  200  ( FIG.  13   ) according to the second embodiment, the pixels  300  ( FIG.  18   ) according to the third embodiment, the pixels  400  ( FIG.  20   ) according to the fourth embodiment, and the pixels  500  ( FIG.  24   ) according to the fifth embodiment are in the structure of surface irradiation type. 
     (Other Exemplary Filter) 
     The description has been made by way of the dual-bandpass filter  141  ( FIG.  8   ), the multilayered filter  241  ( FIG.  13   ), the plasmon filter  341  ( FIG.  18   ), the dual-bandpass filter  441  ( FIG.  20   ), and the multilayered filter  541  ( FIG.  24   ) as a filter functioning as a spectroscopic adjustment layer in the pixels according to the first embodiment to the fifth embodiment, but the filters are exemplary and other filter having a similar spectroscopic adjustment function may be employed. 
     For example, an anti-UV filter which transmits a light in a predetermined wavelength region may be employed instead of the dual-bandpass filter  141  or the dual-bandpass filter  441 . Further, for example, the multilayered filter  241 , the plasmon filter  341 , and the multilayered filter  541  are exemplary filters having a transmission band at least in the infrared region, and other filter having a transmission band in the infrared region may be employed. 
     9. Configuration of Electronic Apparatus 
       FIG.  33    is a diagram illustrating an exemplary configuration of an electronic apparatus having a solid-state imaging apparatus. 
     An electronic apparatus  1000  of  FIG.  33    is, for example, an imaging apparatus such as digital still camera or video camera, a portable terminal apparatus having an imaging function such as Smartphone or tablet terminal, or the like. 
     In  FIG.  33   , the electronic apparatus  1000  is configured of a solid-state imaging apparatus  1001 , a digital signal processor (DSP) circuit  1002 , a frame memory  1003 , a display part  1004 , a recording part  1005 , an operation part  1006 , and a power supply part  1007 . Further, the DSP circuit  1002 , the frame memory  1003 , the display part  1004 , the recording part  1005 , the operation part  1006 , and the power supply part  1007  are mutually connected via a bus line  1008  in the electronic apparatus  1000 . 
     The solid-state imaging apparatus  1001  corresponds to the CMOS image sensor  10  of  FIG.  1   , and a structure of the pixels two-dimensionally arranged in the pixel array part  11  therein employs a structure of pixels corresponding to any of the first embodiment to the fifth embodiment, for example. 
     The DSP circuit  1002  is a signal processing circuit configured to process a signal supplied from the solid-state imaging apparatus  1001 . The DSP circuit  1002  outputs image data obtained by processing the signal from the solid-state imaging apparatus  1001 . The frame memory  1003  temporarily holds the image data processed by the DSP circuit  1002  in units of frame. 
     The display part  1004  is configured of, for example, a panel-type display apparatus such as liquid crystal panel or organic electro luminescence (EL) panel, and displays a moving picture or still image shot by the solid-state imaging apparatus  1001 . The recording part  1005  records image data on a moving picture or still image shot by the solid-state imaging apparatus  1001  in a recording medium such as semiconductor memory or hard disc. 
     The operation part  1006  outputs operation commands for various functions of the electronic apparatus  1000  in response to user&#39;s operations. The power supply part  1007  supplies power to various power supplies as operation power supplies of the DSP circuit  1002 , the frame memory  1003 , the display part  1004 , the recording part  1005 , and the operation part  1006  as needed. 
     The electronic apparatus  1000  is configured as described above. 
     10. Exemplary Use of Solid-State Imaging Apparatus 
       FIG.  34    is a diagram illustrating exemplary use of the CMOS image sensor  10  as an image sensor. 
     The CMOS image sensor  10  ( FIG.  1   ) can be used in various cases for sensing lights such as visible light, infrared ray, ultraviolet ray, and X ray as described below, for example. That is, as illustrated in  FIG.  34   , the CMOS image sensor  10  can be used not only in the field of shooting images to be viewed but also in the field of traffics, in the field of home electronics, in the field of medical care and healthcare, in the field of security, in the field of beauty care, in the field of sports, in the field of agriculture, or the like, for example. 
     Specifically, as described above, the CMOS image sensor  10  can be used in apparatuses (such as the electronic apparatus  1000  of  FIG.  33   ) configured to shoot an image to be viewed, such as digital camera, Smartphone, or camera-equipped cell phone, for example, in the field of viewing. 
     The CMOS image sensor  10  can be used in apparatuses for traffics such as vehicle-mounted sensor configured to shoot in front of, behind, around, inside, and the like of an automobile, monitoring camera configured to monitor a traveling vehicle or a road, or distance measurement sensor configured to measure an inter-vehicle distance or the like in order to achieve safe driving such as automatic stop or to recognize a driver&#39;s state or the like, for example, in the field of traffics. 
     The CMOS image sensor  10  can be used in apparatuses for home electronics such as TV receiver, refrigerator, and air conditioner in order to shoot a user&#39;s gesture and to operate a device according to the gesture, for example, in the field of home electronics. Further, the CMOS image sensor  10  can be used in apparatuses for medical care or healthcare such as endoscope, or angiographic apparatus using received infrared ray, for example, in the field of medical care/healthcare. 
     The CMOS image sensor  10  can be used in apparatuses for security such as monitoring camera for crime prevention or camera for person authentication, for example, in the field of security. Further, the CMOS image sensor  10  can be used in apparatuses for beauty care such as skin measurement device configured to shoot the skin or microscope configured to shoot the scalp, for example, in the field of beauty care. 
     The CMOS image sensor  10  can be used in apparatuses for sports such as action camera or wearable camera for sports or the like, for example, in the field of sports. Further, the CMOS image sensor  10  can be used in apparatuses for agriculture such as camera configured to monitor the states of field or crops, for example, in the field of agriculture. 
     Additionally, embodiments of the present technology are not limited to the above embodiments, and may be variously changed without departing from the spirit of the present technology. 
     Further, the present technology can take the following configurations. 
     (1) 
     A solid-state imaging apparatus including: 
     a pixel array part in which pixels each having a first photoelectric conversion region formed above a semiconductor layer and a second photoelectric conversion region formed in the semiconductor layer are two-dimensionally arranged, 
     in which each of the pixels further has: 
     a first filter configured to transmit a light in a predetermined wavelength region corresponding to a color component; and 
     a second filter having different transmission characteristics from the first filter, 
     one photoelectric conversion region out of the first photoelectric conversion region and the second photoelectric conversion region photoelectrically converts a light in a visible light region and the other photoelectric conversion region photoelectrically converts a light in an infrared region, 
     the first filter is formed above the first photoelectric conversion region, and 
     the second filter has transmission characteristics of making wavelengths of lights in an infrared region absorbed in the other photoelectric conversion region formed below the first filter the same. 
     (2) 
     The solid-state imaging apparatus according to (1), 
     in which the first filter is a color filter. 
     (3) 
     The solid-state imaging apparatus according to (2), 
     in which the first photoelectric conversion region is a photoelectric conversion region configured to absorb and photoelectrically convert a light in a visible light region, and 
     the second photoelectric conversion region is a photoelectric conversion region configured to photoelectrically convert a light in an infrared region. 
     (4) 
     The solid-state imaging apparatus according to (3), 
     in which the second filter is formed above the first filter, and 
     has characteristics of transmitting through at least two wavelength regions including a wavelength region of lights in a visible light region and a wavelength region of lights in an infrared region. 
     (5) 
     The solid-state imaging apparatus according to (3), 
     in which the second filter is formed between the first photoelectric conversion region and the second photoelectric conversion region, and 
     has characteristics of transmitting through a wavelength region of lights at least in an infrared region. 
     (6) 
     The solid-state imaging apparatus according to (5), 
     in which the second filter includes an inorganic film. 
     (7) 
     The solid-state imaging apparatus according to (5) or (6), 
     in which the second filter is a multilayered filter formed by laminating a plurality of materials with different refractive indexes. 
     (8) 
     The solid-state imaging apparatus according to (5), 
     in which the second filter is a metal thin-film filter in which a predetermined microstructural pattern is formed for a metal thin-film. 
     (9) 
     The solid-state imaging apparatus according to (2), 
     in which the first photoelectric conversion region is a photoelectric conversion region configured to absorb and photoelectrically convert a light in an infrared region, and 
     the second photoelectric conversion region is a photoelectric conversion region configured to photoelectrically convert a light in a visible light region. 
     (10) 
     The solid-state imaging apparatus according to (9), 
     in which the second filter is formed above the first filter, and 
     has characteristics of transmitting through at least two wavelength regions including a wavelength region of lights in a visible light region and a wavelength region of lights in an infrared region. 
     (11) 
     The solid-state imaging apparatus according to (9), 
     in which the second filter is a multilayered filter formed by laminating a plurality of materials with different refractive indexes, and 
     has characteristics of transmitting through a wavelength region of lights at least in an infrared region. 
     (12) 
     The solid-state imaging apparatus according to any of (1) to (11), 
     in which each of the pixels has: 
     a first pixel circuit configured of:
         a first charge/voltage conversion part configured to convert a charge photoelectrically converted in the first photoelectric conversion region into a voltage signal;   a first reset transistor configured to reset the first charge/voltage conversion part;   a first amplification transistor configured to amplify the voltage signal from the first charge/voltage conversion part; and   a first select transistor configured to select and output the signal voltage amplified in the first amplification transistor; and       

     a second pixel circuit configured of:
         a second charge/voltage conversion part configured to convert a charge photoelectrically converted in the second photoelectric conversion region into a voltage signal;   a transfer transistor configured to transfer the charge from the second photoelectric conversion region to the second charge/voltage conversion part;   a second reset transistor configured to reset the second charge/voltage conversion part;   a second amplification transistor configured to amplify the voltage signal from the second charge/voltage conversion part; and   a second select transistor configured to select and output the signal voltage amplified in the second amplification transistor, and       

     a feedback amplifier configured to feed back a readout signal from the first pixel circuit to a reset signal of the first reset transistor is provided for the first pixel circuit. 
     (13) 
     An electronic apparatus mounting a solid-state imaging apparatus thereon, the solid-state imaging apparatus including: 
     a pixel array part in which pixels each having a first photoelectric conversion region formed above a semiconductor layer and a second photoelectric conversion region formed in the semiconductor layer are two-dimensionally arranged, 
     in which each of the pixels further has: 
     a first filter configured to transmit a light in a predetermined wavelength region corresponding to a color component; and 
     a second filter having different transmission characteristics from the first filter, 
     one photoelectric conversion region out of the first photoelectric conversion region and the second photoelectric conversion region photoelectrically converts a light in a visible light region, and the other photoelectric conversion region photoelectrically converts a light in an infrared region, 
     the first filter is formed above the first photoelectric conversion region, and 
     the second filter has transmission characteristics of making wavelengths of lights in an infrared region absorbed in the other photoelectric conversion region formed below the first filter the same. 
     REFERENCE SIGNS LIST 
     
         
           10  CMOS image sensor 
           11  Pixel array part 
           12  Vertical drive circuit 
           13  Column processing circuit 
           14  Horizontal drive circuit 
           15  Output circuit 
           16  Control circuit 
           17  I/O terminal 
           100  Pixel 
           111 - 1  R color filter 
           111 - 2  G color filter 
           111 - 3  B color filter 
           112  Organic photoelectric conversion layer 
           115 - 1 ,  115 - 2 ,  115 - 3  Photodiode 
           141  Dual-bandpass filter 
           171  FD part 
           172  Reset transistor 
           173  Amplification transistor 
           174  Select transistor 
           175  Feedback amplifier 
           181  Transfer transistor 
           182  FD part 
           183  Reset transistor 
           184  Amplification transistor 
           185  Select transistor 
           200  Pixel 
           211 - 1  R color filter 
           211 - 2  G color filter 
           211 - 3  B color filter 
           212  Organic photoelectric conversion layer 
           215 - 1 ,  215 - 2 ,  215 - 3  Photodiode 
           241  Multilayered filter 
           300  Pixel 
           311 - 1  R color filter 
           311 - 2  G color filter 
           311 - 3  B color filter 
           312  Organic photoelectric conversion layer 
           315 - 1 ,  315 - 2 ,  315 - 3  Photodiode 
           341  Plasmon filter 
           400  Pixel 
           411 - 1  R color filter 
           411 - 2  G color filter 
           411 - 3  B color filter 
           412  Organic photoelectric conversion layer 
           415 - 1 ,  415 - 2 ,  415 - 3  Photodiode 
           441  Dual-bandpass filter 
           500  Pixel 
           511 - 1  R color filter 
           511 - 2  G color filter 
           511 - 3  B color filter 
           512  Organic photoelectric conversion layer 
           515 - 1 ,  515 - 2 ,  515 - 3  Photodiode 
           541  Multilayered filter 
           1000  Electronic apparatus 
           1001  Solid-state imaging apparatus