Patent Publication Number: US-10763295-B2

Title: Imaging apparatus and electronic device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. National Phase of International Patent Application No. PCT/JP2017/015653 filed on Apr. 19, 2017, which claims priority benefit of Japanese Patent Application No. JP 2016-118961 filed in the Japan Patent Office on Jun. 15, 2016. Each of the above-referenced applications is hereby incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present technology relates to an imaging apparatus and an electronic device. 
     BACKGROUND ART 
     In recent years, solid-state imaging elements such as CMOS image sensors have been widespread, and they are used in place of film-type photographing devices in various fields. The solid-state imaging element is utilized in place of a film-type photographing device in the normal photographing using visible light, and beyond this, it is more utilized than ever in photographing using invisible light such as ultraviolet rays, infrared rays, X-rays, and gamma rays. 
     However, performing visible light photographing and invisible light photographing using the same single solid-state imaging element is not a typical method. Note that a technique for enabling two types of photographing to be performed on the same single solid-state imaging element is disclosed in Patent Document 1, for example. Patent Document 1 discloses a technique of dividing an imaging region of an imaging element, utilizing one of divided imaging regions for normal visible light photographing, and utilizing the other of the divided imaging regions for color spectrum photographing. 
     CITATION LIST 
     Patent Document 
     
         
         Patent Document 1: Japanese Patent Application Laid-Open No. 2012-59865 
       
    
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     In the solid-state imaging element described in Patent Document 1, however, a plasmon resonator as a filter that transmits an electromagnetic wave of a desired wavelength is formed beforehand in a light shielding region layer of constituent pixels of an imaging region used for photographing a color spectrum. That is, the solid-state imaging element described in Patent Document 1 needs to have a structure different from that of a normal solid-state imaging element. 
     The present technology has been made in view of the above problems, and aims to provide an imaging apparatus capable of both visible light photographing and invisible light photographing while using a general solid-state imaging element used for visible light imaging. 
     Solutions to Problems 
     An aspect of the present technology is an imaging apparatus including: a solid-state imaging element having a plurality of pixels two-dimensionally arrayed on an imaging surface; a light shielding unit that shields an invisible light imaging region of the solid-state imaging element in a space above the imaging surface of the solid-state imaging element; a first optical system that allows light corresponding to visible light contained in external light to be incident on the visible light imaging region; and a second optical system that allows light corresponding to invisible light contained in external light to be incident on an invisible light imaging region covered by the light shielding unit. 
     Furthermore, another aspect of the present technology is an electronic device including: a solid-state imaging element having a plurality of pixels two-dimensionally arrayed on an imaging surface; a light shielding unit that shields an invisible light imaging region of the solid-state imaging element in a space above the imaging surface of the solid-state imaging element; a first optical system that allows light corresponding to visible light contained in external light to be incident on the visible light imaging region; a second optical system that allows light corresponding to invisible light contained in external light to be incident on an invisible light imaging region covered by the light shielding unit; and a display apparatus that displays information regarding the invisible light, based on a signal photoelectrically converted on a pixel of the invisible light imaging region. 
     Note that the imaging apparatus described above include various modes such as being implemented in a state of being incorporated in another device or being implemented together with other methods. 
     Effects of the Invention 
     According to the present technology, it is possible to realize an imaging apparatus capable of performing both photographing of both visible light and photographing of invisible light with a solid-state imaging element used for normal visible light photographing. Note that effects described in the present description are provided for purposes of exemplary illustration and are not intended to be limiting. Still other additional effects may also be contemplated. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram illustrating a schematic configuration of an imaging apparatus according to a first embodiment. 
         FIG. 2  is a diagram illustrating a cross-sectional structure of an optical fiber. 
         FIG. 3  is a block diagram illustrating an exemplary configuration of an imaging apparatus according to the first embodiment. 
         FIG. 4  is a diagram illustrating a circuit configuration of a pixel. 
         FIG. 5  is a diagram illustrating a configuration of an AD converter. 
         FIG. 6  is a diagram illustrating an example of an electronic device including the imaging apparatus according to the first embodiment 
         FIG. 7  is a diagram illustrating an example of items displayed on a display interface of an electronic device including the imaging apparatus according to the first embodiment. 
         FIG. 8  is a diagram illustrating a schematic configuration of an imaging apparatus according to a second embodiment. 
         FIG. 9  is a diagram illustrating an example of items displayed on a display interface of an electronic device including the imaging apparatus according to the second embodiment. 
         FIG. 10  is a diagram illustrating a schematic configuration of an imaging apparatus according to a third embodiment. 
         FIG. 11  is a diagram illustrating a schematic configuration of an imaging apparatus according to a fourth embodiment. 
         FIG. 12  is a diagram illustrating a schematic configuration of an imaging apparatus according to a fifth embodiment. 
         FIG. 13  is a diagram illustrating a use mode using two imaging apparatuses. 
         FIG. 14  is a diagram illustrating a method of calculating a distance D. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, the present technology will be described in the following order. 
     (A) First embodiment: 
     (B) Second Embodiment: 
     (C) Third embodiment: 
     (D) Fourth Embodiment: 
     (E) Fifth embodiment: 
     (A) First Embodiment 
       FIG. 1  is a diagram illustrating a schematic configuration of an imaging apparatus  100  according to the present embodiment. 
     The imaging apparatus  100  includes a substrate  10 , a solid-state imaging element  20 , a frame body  30 , a transparent plate  40 , an optical fiber  50 , a scintillator  60 , a light shielding unit  70 , and a lens system  80 . 
     The solid-state imaging element  20  is fixedly mounted on the substrate  10 , and is electrically connected to a land on the substrate  10  via bonding wires, BGA, (not illustrated), or the like. The solid-state imaging element  20  has a configuration similar to a general solid-state imaging element used in visible light imaging and includes an imaging region  21  having a plurality of pixels arrayed in a two-dimensional matrix along an imaging surface  20   a . The imaging region  21  includes an effective pixel region  22  having an array of pixels in which a photoelectric conversion unit is not shielded and an optical black pixel region  23  having an array of pixels in which the photoelectric conversion unit is shielded. 
     In the solid-state imaging element  20 , a portion of the effective pixel region  22  is used as a first region  21   a , while the other portion of the effective pixel region  22  is used as a second region  21   b . The first region  21   a  is a region into which light is incident via a first optical system A and constitutes a visible light imaging region used for capturing visible light. That is, light incident in the first region  21   a  via the first optical system A includes visible light, not including invisible light to which the solid-state imaging element  20  has no photosensitivity, or including very weak invisible light alone that can be disregarded compared with the visible light. The second region  21   b  is a region into which light is incident via a second optical system B, and is an invisible light imaging region used for imaging invisible light. That is, the light incident in the second region  21   b  through the second optical system B includes invisible light in a specific wavelength range, not including visible light, or including very weak invisible light alone that can be disregarded compared with the invisible light having a specific wavelength range. 
     That is, the solid-state imaging element  20  is configured to be able to execute both imaging of visible light using the first optical system A and pixels of the first region  21   a  and photographing of invisible light that uses the second optical system B and pixels of the second region  21   b . Hereinafter, while ultraviolet rays in a predetermined wavelength range will be described as an example of invisible light in a specific wavelength range imaged by using the second region  21   b , invisible light in a specific wavelength range may be infrared rays, X-rays, γ-rays, or the like. Note that the external light indicates light incident from the outside of the first optical system A or the second optical system B. 
     The first optical system A includes a member that directs light according to a visible light component contained in the external light to be incident on the first region  21   a  of the solid-state imaging element  20 . In the present embodiment, the first optical system A includes a frame body  30 , a lens system  80 , and a transparent plate  40 . 
     The frame body  30  is formed on the substrate  10  so as to surround the solid-state imaging element  20 , and is formed to have a greater height than the solid-state imaging element  20  in the shape of a thin plate. A transparent plate  40  is fixed to an upper portion of the frame body  30  so as to cover the upper side of the solid-state imaging element  20  while being separated from the upper surface of the solid-state imaging element  20 . That is, the solid-state imaging element  20  is disposed in a closed space S 1  closed by the substrate  10 , the frame body  30 , and the transparent plate  40 . 
     The transparent plate  40  is constituted with a transparent glass plate or a transparent resin plate and is disposed so that the side surface facing the solid-state imaging element  20  is substantially parallel to the surface of the substrate  10 . The closed space S 1  between the transparent plate  40  and the solid-state imaging element  20  may be in a hollow state, or a solid state filled with a transparent resin or the like. The transparent plate  40  functions as an unwanted light cut filter that cuts unwanted light by providing a coating or the like that reflects unwanted light such as ultraviolet rays and infrared rays within a predetermined wavelength range. 
     The lens system  80  is disposed at a position closer to the light source, above the transparent plate  40 . The lens system  80  collects and emits external light to the imaging surface  20   a  of the solid-state imaging element  20  through the transparent plate  40 . 
     That is, external light from which ultraviolet rays as invisible light in a specific wavelength range have been cut by the unwanted light cut filter function of the transparent plate  40  is emitted onto the imaging surface  20   a  of the solid-state imaging element  20 . 
     The second optical system B is constituted by a member that direct light according to invisible light (ultraviolet rays in the present embodiment) in a specific wavelength range included in external light to be incident on the second region  21   b  of the solid-state imaging element  20 . In the present embodiment, the second optical system B includes the light shielding unit  70 , the optical fiber  50 , and the scintillator  60 . 
     The light shielding unit  70  is a member that shields the second region  21   b  in the space above the solid-state imaging element  20  from light incident on the imaging region  21  via the first optical system A. The light shielding unit  70  covers the entire second region  21   b  to shield the light.  FIG. 1  illustrates a partition wall  71  extending upward from the imaging surface  20   a  of the solid-state imaging element  20  to partition the first region  21   a  from the second region  21   b , and a partition wall  72  extending from the upper end of the partition wall  71  toward the second region  21   b  side in a direction substantially parallel to the imaging surface  20   a  to shield light incident on the imaging region  21  via the first optical system A. Note that he light shielding unit  70  may have a structure as necessary in which the partition walls  71  and  72  and the inner side surface of the frame body  30  is connected so as to cover the second region  21   b  by the light shielding unit  70  coupled to the frame body  30 . Note that the substrate  10  and the frame body  30  together with the light shielding unit  70  are opaque. 
     In this manner, the second region  21   b  is positioned in a light shielding space S 2  integrally closed by the light shielding unit  70 , the substrate  10 , and a portion of the frame body  30  as necessary. Therefore, the light incident on the first region  21   a  via the above-described first optical system A, that is, the light including visible light would not become incident on the second region  21   b.    
     In contrast, an optical fiber  50  constituting the second optical system B directs light corresponding to external light to be incident into the light shielding space S 2  formed on the second region  21   b . The photoelectric conversion unit of the pixel in the second region  21   b  receives light corresponding to external light incident on the second optical system B and generates a charge corresponding to the amount of received light. 
     As the optical fiber  50 , it is allowable to use a hollow core optical fiber capable of transmitting invisible light in a specific wavelength range. 
     The optical fiber  50  is configured to arrange the entrance opening  51  outside the closed space S 1  and the exit opening  52  in the light shielding space S 2  and configured to penetrate the side wall of the closed space S 1  and the side wall of the light shielding space S 2 . In the example illustrated in  FIG. 1 , the S 1  optical fiber  50  is provided to penetrate the side wall of the closed space S 1  and the frame body  30  constituting the side wall of the light shielding space S 2 . 
     The optical fiber  50  includes a wavelength selection filter  56  that prevents incidence of light (electromagnetic wave) in a specific wavelength range from the entrance opening  51 . The wavelength selection filter  56  functions as a bandpass filter of a wavelength to be sensed via the second region  21   b  of the solid-state imaging element  20 , or as a cut filter of visible light as unwanted light. In other words, the optical fiber  50  selectively transmits the invisible light in a specific wavelength range included in the external light incident on the entrance opening  51 , and emits the light from the exit opening  52 . 
     Note that a plasmon filter that transmits invisible light in a specific wavelength range may be provided as the wavelength selection filter  56 . The plasmon filter is constituted by a structure performing plasmon resonance. The structure performing plasmon resonance is, for example, a subwavelength structure obtained by microfabricating a thin film including a conductive material (specifically, silver, aluminum, gold or the like is preferable) having a plasma frequency in the ultraviolet wavelength range. The basic structure of the plasmon resonator is a hole array structure, in which holes (through holes or non-through holes) having a diameter smaller than the detection wavelength are arranged in a two-dimensional array and the dielectric material is filled in the holes. Furthermore, while it is preferable to arrange the holes in a honeycomb or orthogonal matrix, it is possible to apply other arrangements as long as they are periodical structures. 
       FIG. 2  is a diagram illustrating a cross-sectional structure of the optical fiber  50 . As illustrated in the figure, the optical fiber  50  has a cylindrical shape and has a structure in which a core portion  53 , a clad portion  54 , and a cover portion  55  are sequentially and substantially concentrically disposed from the center of the cylinder toward the peripheral portion. The cover portion  55  is a non-light transmitting member that does not transmit visible light or ultraviolet rays as invisible light in a specific wavelength range. With a configuration to cover the periphery of the light guide structure including the core portion  53  and the clad portion  54  with the cover portion  55  of the opaque member, it is possible to prevent the stray light incident from a portion other than the entrance opening  51  from being transmitted through the optical fiber  50 . 
     Note that it also allowable to use, as the optical fiber  50 , a specific light source optical fiber having a high transmittance in a specific wavelength range or a hollow core optical fiber capable of transmitting invisible light in a specific wavelength range without damage. 
     The optical fiber  50  has a V number (normalized frequency) represented by the following Formula (1) is less than 2.405. In the following Formula (1), λ is a wavelength of light to be detected, a is a diameter of the core portion  53 , NA is a numerical aperture of the optical fiber  50 , n 1  is a refractive index of the core portion  53 , and n 2  is a refractive index of the clad portion  54 . 
     
       
         
           
             
               
                 
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     The scintillator  60  is disposed in the vicinity of an imaging surface of the second region  21   b  within the closed space S 1 . The scintillator  60  is disposed between the exit opening  52  of the optical fiber  50  and the second region  21   b  of the imaging surface of the solid-state imaging element  20 . For example, the scintillator  60  is laid just above an imaging surface of the second region  21   b , and the optical fiber  50  is disposed so that light emitted from the exit opening  52  is incident substantially perpendicularly to the imaging surface of the solid-state imaging element  20 . With this arrangement, scintillation light (visible light) excited in the scintillator  60  by the ultraviolet rays emitted from the exit opening  52  of the optical fiber  50  is incident on the second region  21   b.    
     The configuration for performing conversion into an electric signal incident in the imaging region  21  on the above-described solid-state imaging element  20  is similar to that of the conventional solid-state imaging element, and an example thereof will be described below. 
       FIG. 3  is a block diagram illustrating an exemplary configuration of the imaging apparatus  100 . In the present embodiment, a CMOS image sensor which is one type of X-Y address type solid-state imaging element will be described as an example of the imaging apparatus. Hereinafter, a specific example of the imaging apparatus as a CMOS image sensor will be described with reference to  FIG. 3 . 
     In  FIG. 3 , the imaging apparatus  100  includes a pixel portion  121 , a vertical drive unit  122 , an analog/digital converter  123  (AD converter  123 ), a reference signal generation unit  124 , a horizontal drive unit  125 , a communication/timing control unit  126 , and a signal processing unit  127 . 
     The pixel portion  121  includes a two-dimensional array of a plurality of pixels PX including a photodiode as a photoelectric conversion unit. The light receiving surface side of the pixel portion  121  includes a color filter array in which the colors of filters are differentiated corresponding to individual pixels. Note that a specific circuit configuration of the pixel PX will be described later. 
     The pixel portion  121  has wiring of n pixel drive lines HSLn (n=1, 2, . . . ) and m vertical signal lines VSLm (m=1, 2, . . . ). The pixel drive line HSLn is wired so that the length direction is along the right and left direction in the drawing (pixel arrangement direction of the pixel row/horizontal direction) so as to be arranged at equal intervals in the vertical direction in the drawing. The vertical signal line VSLm is wired so that the length direction is along the vertical direction in the drawing (pixel arrangement direction of the pixel column/the vertical direction) so as to be arranged at equal intervals in the horizontal direction of the drawing. 
     One end of the pixel drive line HSLn is connected to an output terminal corresponding to each of rows of the vertical drive unit  122 . The vertical signal line VSLm is connected to the pixel PX in each of the columns, and one end thereof is connected to the AD converter  123 . The vertical drive unit  122  and the horizontal drive unit  125  perform control of sequentially reading analog signals from the individual pixels PX constituting the pixel portion  121  under the control of the communication/timing control unit  126 . Note that specific connections of the pixel drive line HSLn and the vertical signal line VSLm to each of the pixels PX will be described later together with the description of the pixel PX. 
     The communication/timing control unit  126  includes, for example, a timing generator and a communication interface. The timing generator generates various clock signals on the basis of a clock (master clock) input from the outside. The communication interface receives data, or the like, instructing an operation mode given from the outside of the imaging apparatus  100 , and outputs data including internal information of the imaging apparatus  100  to the outside. 
     On the basis of the master clock, the communication/timing control unit  126  generates a clock having the same frequency as that of the master clock, a clock obtained by dividing the clock by two, a low-speed clock obtained by more frequency division, or the like, and supplies generated clocks to individual components (the vertical drive unit  122 , the horizontal drive unit  125 , the AD converter  123 , the reference signal generation unit  124 , and the signal processing unit  127 , or the like). 
     The vertical drive unit  122  is constituted with, for example, a shift register, an address decoder, or the like. The vertical drive unit  122  includes a vertical address setting unit for controlling a row address and a row scanning control unit for controlling row scanning on the basis of a signal obtained by decoding a video signal input from the outside. 
     The vertical drive unit  122  is capable of a read-out scan and a sweep-out scan. 
     Read-out scanning is a scan that sequentially selects unit pixels from which signals are read out. Basically, the read-out scan is performed in order of rows, but in the case of thinning pixels by adding or averaging the outputs of a plurality of pixels in a predetermined positional relationship, they are performed in a predetermined order. 
     Sweep-out scanning is scanning operation for resetting a unit pixel belonging to a row or a pixel combination as a read-out target ahead of the read-out scan by a time corresponding to a shutter speed for the row or the pixel combination as the read-out target in the read-out scan. 
     The horizontal drive unit  125  sequentially selects each of ADC circuits constituting the AD converter  123  in synchronization with the clock output from the communication/timing control unit  126 . The AD converter  123  includes ADC circuits (m=1, 2, . . . ) provided for each of the vertical signal lines VSLm, converts analog signals output from the individual vertical signal lines VSLm into digital signals, and outputs the signal to the horizontal signal line Ltrf under the control of the horizontal drive unit  125 . 
     The horizontal drive unit  125  includes, a horizontal address setting unit and a horizontal scanning unit, for example, and selects individual ADC circuits of the AD converter  123  corresponding to read-out columns in the horizontal direction defined by the horizontal address setting unit, so as to lead the digital signal generated in the selected ADC circuit to the horizontal signal line Ltrf. 
     The digital signal output from the AD converter  123  in this manner is input to the signal processing unit  127  via the horizontal signal line Ltrf. The signal processing unit  127  performs processing of converting a signal output from the pixel portion  121  via the AD converter  123  into an image signal corresponding to the color arrangement of a color filter array by arithmetic processing. 
     Furthermore, the signal processing unit  127  performs processing of thinning the pixel signals in the horizontal direction and the vertical direction by adding, averaging, or the like, as necessary. The image signal generated in this manner is output to the outside of the imaging apparatus  100 . 
     The reference signal generation unit  124  includes a digital-analog converter (DAC), and generates a reference signal Vramp in synchronization with the count clock supplied from the communication/timing control unit  126 . The reference signal Vramp is a saw-tooth wave (ramp waveform) that changes in a stepwise manner from an initial value supplied from the communication/timing control unit  126 . 
     This reference signal Vramp is supplied to each of the ADC circuits of the AD converter  123 . 
     The AD converter  123  includes a plurality of the ADC circuits. In the AD conversion of the analog voltage output from each of pixels PX, the ADC circuit uses a comparator to compare voltage of the reference signal Vramp with the voltage of the vertical signal line VSLm during a predetermined AD conversion period and uses a counter to count any of times before or after reversal of the voltage relationship of the voltage of reference signal Vramp and the voltage (pixel voltage) of the vertical signal line VSLm. This makes it possible to generate a digital signal corresponding to the analog pixel voltage. Note that a specific example of the AD converter  123  will be described later. 
       FIG. 4  is a diagram illustrating a circuit configuration of the pixel PX. 
     This figure illustrates an equivalent circuit of a pixel of a typical 4-transistor configuration. The pixel PX illustrated in the figure includes a photodiode PD and four transistors (a transfer transistor TG, a reset transistor RST, an amplification transistor AMP, and a selection transistor SEL). 
     The photodiode PD generates a current according to the amount of light received by photoelectric conversion. 
     The anode of the photodiode PD is connected to the ground, and its cathode is connected to the drain of the transfer transistor TG. 
     Various control signals are input to the pixel PX from the reset signal generation circuit of the vertical drive unit  122  and various drivers via the signal lines Ltrg, Lrst, or Lsel. 
     A signal line Ltrg for transmitting a transfer gate signal is connected to the gate of the transfer transistor TG. The source of the transfer transistor TG is connected to a connection point between the source of the reset transistor RST and the gate of the amplification transistor AMP. This connection point constitutes a floating diffusion FD which is a capacitance accumulating signal charges. 
     The transfer transistor TG turns on when a transfer signal is input to the gate through the signal line Ltrg and transfers the signal charge accumulated by the photoelectric conversion of the photodiode PD (here, photoelectron) to the floating diffusion FD. 
     A signal line Lrst for transmitting a reset signal is connected to the gate of the reset transistor RST, while a constant voltage source VDD is connected to the drain. The reset transistor RST turns on when a reset signal is input to the gate through the signal line Lrst and resets the floating diffusion FD to the voltage of the constant voltage source VDD. In contrast, in a case where the reset signal is not input to the gate through the signal line Lrst, the reset transistor RST is turned off, and a predetermined potential barrier is formed between the floating diffusion FD and the constant voltage source VDD. 
     The amplification transistor AMP has a gate connected to the floating diffusion FD, a drain connected to the constant voltage source VDD, and a source connected to the drain of the selection transistor SEL. 
     In the selection transistor SEL, the signal line Lsel of the selected signal is connected to the gate, and the source is connected to the vertical signal line VSLm. The selection transistor SEL turns on when a control signal (address signal or select signal) is input to the gate through the signal line Lsel and turns off in a case where this control signal is not input to the gate through the signal line Lsel. 
     When the selection transistor SEL is turned on, the amplification transistor AMP amplifies the voltage of the floating diffusion FD and outputs the amplified voltage to the vertical signal line VSLm. The voltage output from each of pixels PX through the vertical signal line VSLm is input to the AD converter  123 . 
     Note that as the circuit configuration of the pixel PX, it is also possible to adopt various well-known configurations such as a three-transistor system configuration or another four-transistor system configuration, other than the configuration illustrated in  FIG. 4 . For example, an example of a configuration of another four-transistor system includes a configuration in which the selection transistor SEL is disposed between the amplification transistor AMP and the constant voltage source VDD. 
       FIG. 5  is a diagram illustrating a configuration of the AD converter  123 . As illustrated in the figure, each of the ADC circuits constituting the AD converter  123  includes a comparator  123   a  and a counter  123   b  provided for each of vertical signal line VSLm, and a latch  123   c.    
     The comparator  123   a  has two input terminals T 1  and T 2 , and one output terminal T 3 . One input terminal T 1  receives an input of a reference signal Vramp from the reference signal generation unit  124  and the other input terminal T 2  receives an input of an analog pixel signal (hereinafter referred to as pixel signal Vvsl) output from the pixel PX via the vertical signal line VSLm). 
     The comparator  123   a  compares the reference signal Vramp and the pixel signal Vvsl. The comparator  123   a  outputs a high level or low level signal in accordance with the magnitude relation between the reference signal Vramp and the pixel signal Vvsl. When the magnitude relation between the reference signal Vramp and the pixel signal Vvsl is switched, the output of the output terminal T 3  is inverted between the high level and the low level. 
     The counter  123   b  receives a clock supplied from the communication/timing control unit  126 , and uses this clock to count the time from the start to the end of the AD conversion. The timing of the start and end of the AD conversion is specified on the basis of the control signal (for example, the presence or absence of the input of the clock signal CLK, or the like) output from the communication/timing control unit  126  and on the basis of output inversion of the comparator  123   a.    
     Furthermore, the counter  123   b  performs AD conversion on the pixel signal by correlated double sampling (CDS). Specifically, under the control of the communication/timing control unit  126 , the counter  123   b  performs down-counting while an analog signal corresponding to a reset component is output from the vertical signal line VSLm. Then, the count value obtained by the down-counting is set as an initial value, and up-counting is performed while the analog signal corresponding to the pixel signal is output from the vertical signal line VSLm. 
     The count value generated in this manner is a digital value corresponding to the difference between the signal component and the reset component. In other words, the count value is a value obtained by calibrating, by using the reset component, a digital value corresponding to the analog pixel signal input from the pixel PX to the AD converter  123  through the vertical signal line VSLm. 
     The digital value generated by the counter  123   b  is stored in the latch  123   c  and sequentially output from the latch  123   c  under the control of the horizontal scanning unit and then output to the signal processing unit  127  via the horizontal signal line Ltrf. 
       FIG. 6  is a diagram illustrating an example of an electronic device  150  including the imaging apparatus  100  described above. 
     Note that the electronic device  150  represents a general electronic device using a solid-state imaging element as an image capturing unit (photoelectric conversion unit), such as an imaging apparatus including a digital still camera or a digital video camera, a mobile terminal device such as a mobile phone having an imaging function, for example. Obviously, an electronic device using a solid-state imaging element in the image capturing unit also includes a copying machine using a solid-state imaging element in the image reading unit. Furthermore, the imaging apparatus may be a module including a solid-state imaging element so as to be mounted on the above-described electronic device. 
     In  FIG. 6 , the electronic device  150  includes an optical system  161  including a lens group, a solid-state imaging element  162 , a digital signal processor (DSP)  163  as a signal processing circuit for processing output signals of the solid-state imaging element  162 , a frame memory  164 , a display apparatus  165 , a recording apparatus  166 , an operation system  167 , a power supply system  168 , and a control unit  169 . Note that the solid-state imaging element  162  corresponds to the solid-state imaging element  20 , and the optical system  161  corresponds to the first optical system A and the second optical system B. 
     The DSP  163 , the frame memory  164 , the display apparatus  165 , the recording apparatus  166 , the operation system  167 , the power supply system  168 , and the control unit  169  are mutually connected so as to be able to exchange data and signals with each other via a communication bus. 
     The optical system  161  captures incident light (image light) from a subject and forms an image on an imaging surface of the solid-state imaging element  162 . The solid-state imaging element  162  generates an electric signal corresponding to the amount of received incident light formed on the imaging surface by the optical system  161  in units of pixels, and outputs the generated electric signal as a pixel signal. This pixel signal is input to the DSP  163  to undergo various image processing appropriately, and thereafter stored in the frame memory  164 , recorded on a recording medium of the recording apparatus  166 , or output to the display apparatus  165 . 
     The display apparatus  165  is a panel type display apparatus such as a liquid crystal display apparatus or an organic electro luminescence (EL) display apparatus, and displays moving images and still images captured by the solid-state imaging element  162 , and other information. The recording apparatus  166  records the moving image and the still image captured by the solid-state imaging element  162  on a recording medium such as a digital versatile disk (DVD), a hard disk (HD), or a semiconductor memory. 
     The operation system  167  receives various operations from the user, and transmits an operation command corresponding to the operation of the user to each of the units  163 ,  164 ,  165 ,  166 ,  168 , and  169  via the communication bus. The power supply system  168  generates various power supply voltages as drive power supply and supplies the voltages appropriately to the supply targets (the respective sections  162 ,  163 ,  164 ,  165 ,  166 ,  167 , and  169 ). 
     The control unit  169  includes a CPU that performs arithmetic processing, a ROM that stores a control program of the electronic device  150 , a RAM that functions as a work area of the CPU, and the like. The control unit  169  causes the CPU to execute a control program stored in the ROM while using the RAM as a work area so as to control each of the units  163 ,  164 ,  165 ,  166 ,  167 , and  168  via the communication bus Furthermore, the control unit  169  controls a timing generator (not illustrated) to generate various timing signals and performs control to supply the timing signals to each of units. 
     The electronic device  150  described above enables display as illustrated in  FIG. 7 , for example. 
     The figure illustrates an example of items displayed on a display interface of a mobile communication device as the electronic device  150 . The display interface displays a variety of information based on the amount of received ultraviolet rays, for example, intensity of ultraviolet rays as invisible light in a specific wavelength range, a standard indicating safety based on the intensity of the ultraviolet rays (Good/Normal/Caution, etc.), and remaining allowable activity time under the ultraviolet rays (or time to be exposed to the ultraviolet rays), for example. With this configuration, the user of the electronic device  150  can obtain information regarding the ultraviolet rays contained in the external light, based on an actual measurement result of the electronic device  150 . 
     (B) Second Embodiment 
       FIG. 8  is a diagram illustrating a schematic configuration of an imaging apparatus  200  according to the present embodiment. 
     The imaging apparatus  200  differs from the imaging apparatus  100  described above in that it has a plurality of optical fibers to transmit ultraviolet rays as invisible light in a specific wavelength range to the second region  21   b . Still, the other configurations are common to the imaging apparatus  100  and therefore, a detailed description of the configuration other than the optical fiber will be omitted, and the same reference numerals as the imaging apparatus  100  will be used in the description. 
     As illustrated in  FIG. 8 , the imaging apparatus  200  includes a plurality of optical fibers  50   a  to  50   d.    
     Each of the optical fibers  50   a  to  50   d  allows light corresponding to external light to be incident into the light shielding space S 2  formed on the second region  21   b , specifically, light corresponding to external light to be incident in mutually different regions (pixels) within the second region  21   b.    
     The optical fibers  50   a  to  50   d  can transmit ultraviolet rays of mutually different types (frequencies) with V numbers (normalized frequencies) represented by the above Formula (1) being mutually different within a range of 2.405 or less. Note that it is also allowable to use, as the optical fibers  50   a  to  50   d , hollow core optical fibers having mutually different frequencies of ultraviolet rays to be transmitted. 
     In a case where the above-described electronic device  150  includes the imaging apparatus  200 , for example, display as illustrated in  FIG. 9  is possible. The figure illustrates an example of items displayed on a display interface of a mobile communication device as the electronic device  150 . The display interface displays a variety of information based on the amount of received ultraviolet rays, for example, intensity of ultraviolet rays for each of types of ultraviolet rays (UV-C, UV-B, UV-A, etc.), an index of safety based on the intensity of each of types of ultraviolet rays (Good/Normal/Caution, etc.), and remaining allowable activity time under these ultraviolet rays (or time to be exposed to the ultraviolet rays), for example. With this configuration, the user of the electronic device  150  can obtain information regarding the ultraviolet rays contained in the external light, based on an actual measurement result of the electronic device  150 , for each of the wavelength ranges of the ultraviolet rays. 
     (C) Third Embodiment 
       FIG. 10  is a diagram illustrating a schematic configuration of an imaging apparatus  300  according to the present embodiment. 
     The imaging apparatus  300  includes a substrate  310 , a solid-state imaging element  320 , a frame body  330 , a transparent plate  340 , a scintillation fiber  350 , a light shielding unit  370 , and a lens system  380 . 
     Note that the imaging apparatus  300  according to the present embodiment has a similar configuration to the imaging apparatus  100  according to the first embodiment, except that the scintillation fiber  350  is included in place of the optical fiber  50  and the scintillator  60 . Therefore, in the following description, similar configuration to that of the imaging apparatus  100  (the substrate  310 , the solid-state imaging element  320 , the frame body  330 , the transparent plate  340 , the light shielding unit  370 , the lens system  380 , or the like) will be described with corresponding reference numerals (with “3” added to the heads of the signs in the configuration of the imaging apparatus  100 ) and detailed description thereof will be omitted. 
     A first optical system  3 A includes a member that guides external light to be incident into a first region  321   a  of the solid-state imaging element  320 , specifically includes the frame body  330 , the lens system  380 , and the transparent plate  340 , in the present embodiment. 
     The second optical system  3 B includes a member that guides external light to be incident into a second region  321   b  of the solid-state imaging element  320 , specifically includes the light shielding unit  370  and the scintillation fiber  350 , in the present embodiment. 
     Specifically, however, the scintillation fiber  350  constituting the second optical system  3 B allows light corresponding to external light different from the external light incident on the first optical system  3 A, to be incident into a light shielding space  3 S 2  formed above the second region  321   b . The photoelectric conversion unit of the pixel in the second region  321   b  receives light corresponding to external light incident on the second optical system  3 B and generates a charge corresponding to the received light amount. 
     The scintillation fiber  350  is configured to arrange an entrance opening  351  outside a closed space  3 S 1  and an exit opening  352  in the light shielding space  3 S 2  and configured to penetrate the side wall of the closed space  3 S 1  and the side wall of the light shielding space  3 S 2 . In the example illustrated in  FIG. 10 , the scintillation fiber  350  is provided to penetrate through the closed space  3 S 1  and the frame body  330  constituting the side wall of the light shielding space  3 S 2 . 
     The entrance opening  351  of the scintillation fiber  350  includes a wavelength selection filter  356  that prevents incidence of light (electromagnetic wave) in a specific wavelength range from the entrance opening  351 . The wavelength selection filter  356  functions as a bandpass filter of a wavelength to be sensed via the second region  321   b  of the solid-state imaging element  320 , or as a cut filter of visible light as unwanted light. 
     A plasmon filter that transmits invisible light in a specific wavelength range may be provided as the wavelength selection filter  356 . That is, the scintillation fiber  350  allows invisible light in a specific wavelength range included in external light incident on the entrance opening  351  to be selectively incident, and allows the scintillation light corresponding to the invisible light in the specific wavelength range to be emitted from the exit opening  52 . With this configuration, invisible light of a specific wavelength range of external light (ultraviolet rays in the present embodiment) is selectively incident on the scintillation fiber  350 . Accordingly, the scintillation fiber  350  transmits scintillation light generated in accordance with the amount of ultraviolet rays contained in the external light incident on the entrance opening  351  so as to exit the light from the exit opening  352 . The intensity of the scintillation light sensed in this manner can be sensed as the intensity of ultraviolet rays and a variety of information based on the amount of received ultraviolet rays can be displayed, similarly to the first embodiment and the second embodiment. 
     (D) Fourth Embodiment 
       FIG. 11  is a diagram illustrating a schematic configuration of an imaging apparatus  400  according to the present embodiment. 
     The imaging apparatus  400  includes a substrate  410 , a solid-state imaging element  420 , a frame body  430 , a transparent plate  440 , a scintillator  460 , a light shielding unit  470 , and a lens system  480 . 
     Note that the imaging apparatus  400  according to the present embodiment has a configuration similar to the imaging apparatus  100  according to the first embodiment except that the optical fiber  50  is not provided and the structures of the transparent plate  440  and the light shielding unit  470  are different from the imaging apparatus  100 . Therefore, in the following description, the configuration similar to that of the imaging apparatus  100  (the substrate  410 , the solid-state imaging element  420 , the frame body  430 , the lens system  480 , or the like) will be described with corresponding reference numerals (with “4” added to the heads of the signs of the configuration of the imaging apparatus  100 ) and detailed description thereof will be omitted. 
     In the present embodiment, a first optical system  4 A includes members so that light corresponding to a visible light component included in external light incident through the lens system  480  can be incident on a first region  421   a  of the solid-state imaging element  420 , specifically includes the frame body  430 , the lens system  480 , and the transparent plate  440 , in the present embodiment. 
     Another one, that is, a second optical system  4 B includes a member that guides the invisible light component (ultraviolet component in the present embodiment) of a specific wavelength range of external light incident through the lens system  480  to the second region  421   b  of the solid-state imaging element  420 , specifically, includes the transparent plate  440 , the light shielding unit  470 , and the scintillator  460 , in the present embodiment. 
     While the transparent plate  440  is similar to the case of the first embodiment in that it is fixed to the upper part of the frame body  430  so as to cover the upper side of the solid-state imaging element  420 , it is different from the case of the first embodiment in the structure that does not cover the upper part of the second region  421   b  although it covers the first region  421   a  of the solid-state imaging element  420 . 
     The light shielding unit  470  is the similar to the case of the first embodiment in that it partitions the first region  421   a  from the second region  421   b  in a space between the solid-state imaging element  420  and the transparent plate  440 . In the present embodiment, however, the light shielding unit  470  is formed as a partition wall  471  that reaches from the upper surface of the solid-state imaging element  420  to the lower surface of the transparent plate  440 . Note that the light shielding unit  470  may also have a shape to connect the partition wall  471  to the inner surface of the frame body  430  as necessary. 
     In this manner, in the present embodiment, the second region  421   b  is configured as the imaging region  421  of the solid-state imaging element  420 , disposed at the bottom of a surrounding space  4 S 2  in which light shielding unit  470  and the substrate  410  and a portion of the frame body  430  as necessary are integrated. 
     The upper opening of a surrounding space  4 S 1  is connected to the space between the upper surface of the transparent plate  440  and the lens system  480  and is configure so that he light having passed through the transparent plate  440  would not enter the surrounding space  4 S 2  whereas the light reflected on the upper surface of the transparent plate  440  is capable of entering the surrounding space  4 S 2 . Furthermore, the upper opening of the surrounding space  4 S 2  is provided so as to be located outside an image circle of the light that passes through the lens system  480  to be emitted to the solid-state imaging element  420 . Accordingly, light that passes through the lens system  480  does not directly enter the second region  421   b.    
     The transparent plate  440  is disposed so that the side surface facing the solid-state imaging element  420  is substantially parallel to the surface of the substrate  410 . The closed space  4 S 1  between the transparent plate  440  and the solid-state imaging element  420  may be in a hollow state or solid state filled with a transparent resin or the like. The transparent plate  440  functions as an unwanted light cut filter that cuts unwanted light by providing a coating or the like that reflects unwanted light such as ultraviolet rays and infrared rays within a predetermined wavelength range. 
     The lens system  480  is disposed at a position closer to the light source, above the transparent plate  440 . The lens system  480  collects and emits external light to the imaging surface  420   a  of the solid-state imaging element  420  through the transparent plate  440 . That is, external light from which ultraviolet rays have been cut by the unwanted light cut filter function of the transparent plate  440  is emitted onto the imaging surface  420   a  of the solid-state imaging element  420 . Note that the surrounding space  4 S 2  is closed so as to suppress incidence of the external light other than the light passing through the lens system  480  to be incident on the imaging apparatus  400 . 
     The ultraviolet rays reflected on the surface of the transparent plate  440  are incident into the surrounding space  4 S 1  due to reflection or the like and are incident above the scintillator  460  disposed on the second region  421   b . Above the scintillator  460 , a wavelength selection filter  461  for preventing incidence of light (electromagnetic wave) in a specific wavelength range is provided. The wavelength selection filter  461  functions as a bandpass filter of a wavelength to be sensed via the second region  421   b  of the solid-state imaging element  420 , or as a cut filter of visible light as unwanted light. A plasmon filter that transmits invisible light in a specific wavelength range may be provided as the wavelength selection filter  356 . In other words, the scintillator  460  selectively receives incidence of invisible light in a specific wavelength range included in incident light. The scintillator  460  generates scintillation light in an amount corresponding to the incident ultraviolet rays, and the generated scintillation light is received by the pixels constituting the second region  421   b . In this manner, the intensity of the scintillation light sensed by the second region  421   b  is sensed as the intensity of the ultraviolet rays, and a variety of information based on the amount of received ultraviolet rays can be displayed similarly to the first embodiment and the second embodiment described above. 
     (E) Fifth Embodiment 
       FIG. 12  is a diagram illustrating a schematic configuration of an imaging apparatus  500  according to the present embodiment. 
     The imaging apparatus  500  includes a substrate  510 , a solid-state imaging element  520 , a light shielding unit  570  having a pinhole, a scintillation fiber  550 , and an optical fiber  555 . 
     The solid-state imaging element  520  is fixedly mounted on the substrate  510 , and is electrically connected to a land on the substrate  510  via wire bonding or BGA (not illustrated) or the like. Similarly to the solid-state imaging element  20  according to the first embodiment, the solid-state imaging element  520  includes an imaging region constituted by an effective pixel region and an optical black pixel region. 
     The light shielding unit  570  is formed by using a material that shields invisible light, for example, lead or tungsten in a case where the invisible light is X-rays or γ rays. The light shielding unit  570  is formed so as to cover the entire solid-state imaging element  520  on the substrate  510  excluding a through hole  571  through which a scintillation fiber is inserted, and is configured to shield the solid-state imaging element  520  from invisible light from the outside. 
     Hereinafter, a space substantially closed by the light shielding unit  570  above the substrate  510  will be referred to as a shielding space  5 S 1 . 
     The light shielding unit  570  includes a pinhole-shaped concave portion  572  on the outer surface, and a plurality of through holes  571   a  to  571   e  linearly penetrating from the inside of the hole of the concave portion  572  to the shielding space  5 S 1  are radially formed from the center of the concave portion  572 . Note that the through holes  571  illustrated in  FIG. 12  are conceptually illustrated, and its quantity, length, density, etc. can be appropriately adjusted. 
     A pinhole diameter D 1  of the concave portion  572  is set by the following Formula (2), for example, set to φ=0.08 mm in a case where f=5 mm. The light incident on the concave portion  572  can be incident into the shielding space  5 S 1  through the through holes  571   a  to  571   e  in the case where the light travels along any of extending directions of the through holes  571   a  to  571   e . However, the light traveling along the direction different from any of the extending direction of the through holes  571   a  to  571   e  is shielded by the light shielding unit  570  and cannot be incident into the shielding space  5 S 1 . 
     
       
         
           
             
               
                 
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     Linear scintillation fibers  550   a  to  550   e  are inserted through the through holes  571   a  to  571   e , respectively. Invisible light incident through the pinhole-shaped concave portion  572  enters an end portion of the scintillation fibers  550   a  to  550   e  on the concave portion  572  side. Subsequently, invisible light rays substantially in agreement with the extending direction of the scintillation fibers  550   a  to  550   e  alone are guided through the scintillation fibers  550   a  to  550   e  along the extending direction of the scintillation fibers  550   a  to  550   e  (extending direction of the through holes). 
     The scintillation fibers  550   a  to  550   e  generates fluorescence when invisible light strikes a fluorescent substance in the scintillation fibers  550   a  to  550   e  while being guided through the fibers. Each of the scintillation fibers  550   a  to  550   e  has a length to achieve collision probability (probability that invisible light generates scintillation) between invisible light passing through the fiber and the fluorescent substance, of a certain value or more (for example, 70% or more). 
     For example, in order to achieve the collision probability of 70% or more between hard X-ray of 50 keV as invisible light and fluorescent substance in a case where a scintillation fiber of model number BCF-20 of Saint-Gobain K.K. is used, each of scintillation fibers  550   a  to  550   e  shall be 5 cm or more in length. 
     Furthermore, for example, in order to achieve the collision probability of 70% or more between hard X-ray or γ ray of 100 keV as invisible light and fluorescent substance in a case where a scintillation fiber of model number BCF-20 of Saint-Gobain K.K. is used, each of scintillation fibers  550   a  to  550   e  shall be 7.5 cm or more in length. 
     Furthermore, for example, in order to achieve the collision probability of 70% or more between the γ ray of 200 keV as invisible light and fluorescent substance in a case where a scintillation fiber of model number BCF-20 of Saint-Gobain K.K. is used, each of scintillation fibers  550   a  to  550   e  shall be 10 cm or more in length. 
     Optical fibers  555   a  to  555   e  are connected to the end portions of the scintillation fibers  550   a  to  550   e  on the shielding space  5 S 1  side, respectively. The optical fibers  555   a  to  555   e  have a cross-sectional structure similar to that of the optical fiber  50  in the above-described first embodiment. 
     The optical fibers  555   a  to  555   e  extend to connect between the scintillation fibers  550   a  to  550   e  and portions in the vicinity of the surface of the solid-state imaging element  520 , and guide the light emitted from the scintillation fibers  550   a  to  550   e  to the surface of the solid-state imaging element  520 . 
     The optical fibers  555   a  to  555   e  extend at mutually different positions in the imaging region  521  while maintaining mutual positional relationship in the scintillation fibers  550   a  to  550   e  in a direction along the imaging surface  520   a . The light guided by each of the optical fibers  555   a  to  555   e  is incident on each of mutually different pixels (different imaging regions). 
     As a result, external light is incident on the solid-state imaging element  520  in a positional relationship in which the vertical and horizontal positions are inverted with the concave portion  572  as a center of symmetry, that is, obtained incident light is the incident light corresponding to each of points of an image that is a reduced and vertically and horizontally inverted version of the invisible light incident from the subject. The image formed in accordance with the light incident on the solid-state imaging element  520  in this manner is an image indicating the intensity distribution of the invisible light incident from the subject. In a case where the invisible light is X-ray, the obtained image is similar to X-ray photograph; in a case where the invisible light is γ ray, an obtained image is similar to a gamma camera image. 
     Additionally, it is also allowable to provide an invisible light source  590  that emits X-rays or γ-rays, as invisible light. In this case, for example, a subject such as a human body is arranged between the invisible light source  590  and the concave portion  572 , and invisible light emitted from the invisible light source  590  passes through the subject and is incident on the concave portion  572 . Among the light transmitted through the subject, the light that travels in the direction that agrees with the extending direction of any of the scintillation fibers generates scintillation light within the scintillation fiber while the light passes along the scintillation fibers  550   a  to  550   e.    
     The invisible light source  590  is configured to be movable to change its position in various manners by a drive device (not illustrated), and to enable scanning at each of positions where the invisible light transmitted through the subject is to be incident onto the scintillation fibers  550   a  to  550   e . The image created by the imaging apparatus  500  in accordance with the amount of light received by the solid-state imaging element  520  during this scanning period is to be a transmission image of X-rays or γ-rays of the subject. The scanning range of the invisible light source  590  includes a range of a vertical angle φ 2  of a solid angle φ 1  at which the scintillation fibers  550   a  to  550   e  are provided, with the concave portion  572  as a center of symmetry. 
     Furthermore, the two imaging apparatuses  500  can be used to measure the depth of the affected portion in the body of a patient as a subject. Hereinafter, two imaging apparatuses will be denoted by  500 A and  500 B.  FIG. 13  is a diagram illustrating a use mode using two imaging apparatuses  500 . 
     In this case, the imaging apparatus  500 A and the imaging apparatus  500 B are arranged side by side while being separated by a fixed length, and invisible light emitted from the same single invisible light source  590  and transmitted through the subject is captured by both of the imaging apparatuses  500 A and  500 B. 
     The scanning range of the invisible light source  590  is set within a range including both a range of a vertical angle φ 2 A of a solid angle φ 1 A of the scintillation fiber provided in the imaging apparatus  500 A with a concave portion  572 A of the imaging apparatus  500 A as a center and a range of the vertical angle φ 2 B of a solid angle φ 1 B of the scintillation fiber provided in the imaging apparatus  500 B with a concave portion  572 B of the imaging apparatus  500 B as a center. 
     At this time, a distance D 2  between the straight line connecting the concave portioned portion  527 A of the imaging apparatus  500 A with the concave portioned portion  527 B of the imaging apparatus  500 B and an affected portion Z can be expressed by the following Formula (3).  FIG. 14  is a diagram illustrating a method of calculating the distance D 2 . Note that a line perpendicular to the straight line connecting the concave portion  527 A and the concave portion  527 B will be referred to as a normal in the following. 
     
       
         
           
             
               
                 
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     In Formula (3), W is a distance between the concave portion  527 A of the imaging apparatus  500 A and the concave portion  572 B of the imaging apparatus  500 B, θ 1  is an angle between the scintillation fiber through which light that has entered the pixel of the imaging apparatus  500 A that photographed the affected portion Z whose depth is wanted, and the normal (angle of the invisible light that passed through the affected portion Z and then reached the concave portion  572 A), and θ 2  is an angle between the scintillation fiber through which light that has entered the pixel of the imaging apparatus  500 B that photographed the affected portion Z whose depth is wanted, and the normal (angle of the invisible light that passed through the affected portion Z and then reached the concave portion  572 ). Furthermore, x represents a distance between an intersection C with the normal passing through the affected portion Z and the concave portion  527 A on a straight line connecting the concave portioned part  527 A and the concave portioned part  527 B. 
     As illustrated in Formula (3), the distance D 2  can be expressed without using the distance x. 
     Additionally, the distance W is known in Formula (3) and the angles θ 1  and θ 2  are values determined from the photographed image, and thus, the depth of the affected portion Z can be obtained from Formula (3). As described above, according to the imaging apparatus  500  of the present embodiment, it is possible to capture an image similar to an X-ray photograph or a gamma camera image. Furthermore, it is also possible to measure the depth of the affected portion Z by imaging by the imaging apparatus  500  arranged side by side. 
     Note that the present technology is not limited to each of the above-described embodiments and includes configurations including mutual replacement or various modifications of combinations of individual formations disclosed in the above embodiments, configurations including mutual replacement or various modifications of combinations of individual formations disclosed in known technologies and the above embodiments, or the like. Furthermore, the technical scope of the present technology is not limited to the above-described embodiments, but extends to matters described in the claims and their equivalents. 
     Moreover, the present technology may also be configured as below. 
     (1) 
     An imaging apparatus including: 
     a solid-state imaging element having a plurality of pixels two-dimensionally arrayed on an imaging surface; 
     a light shielding unit that shields an invisible light imaging region of the solid-state imaging element in a space above the imaging surface of the solid-state imaging element; 
     a first optical system that allows light corresponding to visible light contained in external light to be incident on the visible light imaging region of the solid-state imaging element; and 
     a second optical system that allows light corresponding to invisible light contained in external light to be incident on an invisible light imaging region covered by the light shielding unit. 
     (2) 
     The imaging apparatus according to (1), 
     in which the second optical system includes an optical fiber that guides the invisible light contained in the external light to the invisible light imaging region. 
     (3) 
     The imaging apparatus according to (1), 
     in which the second optical system includes a scintillation fiber that guides scintillation light generated by invisible light contained in the external light to the invisible light imaging region. 
     (4) 
     The imaging apparatus according to (3), 
     in which a filter that selectively passes the invisible light is provided in an entrance opening of the scintillation fiber in the second optical system. 
     (5) 
     The imaging apparatus according to (1), 
     in which the first optical system includes a cut filter that reflects ultraviolet rays as invisible light contained in the external light, and 
     the second optical system includes a portion that guides the ultraviolet rays reflected by the cut filter to the invisible light imaging region. 
     (6) 
     The imaging apparatus according to (1), 
     in which the first optical system includes a cut filter that reflects infrared rays as invisible light contained in the external light, and 
     the second optical system includes a light guide structure that guides the infrared rays reflected by the cut filter to the invisible light imaging region. 
     (7) 
     An electronic device including: 
     a solid-state imaging element having a plurality of pixels two-dimensionally arrayed on an imaging surface; 
     a light shielding unit that shields an invisible light imaging region of the solid-state imaging element in a space above the imaging surface of the solid-state imaging element; 
     a first optical system that allows light corresponding to visible light contained in external light to be incident on the visible light imaging region; 
     a second optical system that allows light corresponding to invisible light contained in external light to be incident on an invisible light imaging region covered by the light shielding unit; and 
     a display apparatus that displays information regarding the invisible light, based on a signal photoelectrically converted on a pixel of the invisible light imaging region. 
     REFERENCE SIGNS LIST 
     
         
           10  Substrate 
           20  Solid-state imaging element 
           20   a  Imaging surface 
           21  Imaging region 
           21   a  First region 
           21   b  Second region 
           22  Effective pixel region 
           23  Optical black pixel region 
           30  Frame body 
           40  Transparent plate 
           50  Optical fiber 
           50   a  to  50   d  Optical fiber 
           51  Entrance opening 
           52  Exit opening 
           53  Core portion 
           54  Clad portion 
           55  Cover portion 
           56  Wavelength selection filter 
           60  Scintillator 
           70  Light shielding unit 
           71  Partition wall 
           72  Partition wall 
           80  Lens system 
           100  Imaging apparatus 
           200  Imaging apparatus 
           300  Imaging apparatus 
           310  Substrate 
           320  Solid-state imaging element 
           321   a  First region 
           321   b  Second region 
           330  Frame body 
           340  Transparent plate 
           350  Scintillation fiber 
           351  Entrance opening 
           352  Exit opening 
           370  Light shielding unit 
           380  Lens system 
           400  Imaging apparatus 
           410  Substrate 
           420  Solid-state imaging element 
           420   a  Imaging surface 
           421  Imaging region 
           421   a  First region 
           421   b  Second region 
           430  Frame body 
           440  Transparent plate 
           460  Scintillator 
           470  Light shielding unit 
           471  Partition wall 
           480  Lens system 
           500  Imaging apparatus 
           510  Substrate 
           520  Solid-state imaging element 
           521  Imaging region 
           522  Effective pixel region 
           523  Optical black pixel region 
           550 ,  550   a  to  550   e  Scintillation fiber 
           555 ,  555   a  to  555   e  Optical fiber 
           570  Light shielding unit 
           571 ,  571   a  to  571   e  Through hole 
           572  Concave portion 
         A First optical system 
         B Second optical system 
           3 A First optical system 
           3 B Second optical system 
           4 A First optical system 
           4 B Second optical system