Light detection device, electronic apparatus, and method for driving light detection device

Abstract

The imaging element according to an embodiment of the present invention includes a first photoelectric conversion part and a second photoelectric conversion part which are stacked in this order from a light incident side and which selectively detect light beams of different wavelength bands and perform photoelectric conversion, and the second photoelectric conversion parts are arranged at intervals narrower than the pixel pitch of the first photoelectric conversion parts.

Description

[0001] This application is a divisional application of patent application No. 201980032183.6, whose application date is April 24, 2019 and whose invention name is “Imaging element, electronic device and driving method of imaging element”. Technical Field

[0002] The present invention relates to, for example, an imaging element in which a plurality of photoelectric conversion portions are stacked in a vertical direction, an electronic device, and a method of driving the imaging element. Background Art

[0003] In recent years, progress has been made in the miniaturization of pixel sizes in solid-state imaging devices such as CCD (charge coupled device) image sensors or CMOS (complementary metal oxide semiconductor) image sensors. This results in a reduction in the number of photons entering a unit pixel, resulting in a decrease in sensitivity and a signal-to-noise ratio. In addition, in the case of using a color filter that arranges red, green, and blue primary color filters in two dimensions for coloring, for example, green and blue light beams are absorbed by the color filter in the red pixel, resulting in a decrease in sensitivity. In addition, interpolation processing is performed between pixels when generating each color signal, resulting in the occurrence of so-called false colors.

[0004] Therefore, for example, Patent Document 1 discloses a so-called vertical beam splitting solid-state imaging device in which an organic photoelectric conversion unit including an organic photoelectric conversion film and two inorganic photoelectric conversion units each having a pn junction in a semiconductor substrate are stacked. In this solid-state imaging device, signals of B (blue) / G (green) / R (red) are obtained from one pixel, respectively, thereby achieving improved sensitivity.

[0005] Reference List

[0006] Patent Literature

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2011-29337 Summary of the invention

[0008] Incidentally, the vertical splitting imaging device as described above is expected to achieve both resolution and graininess.

[0009] It is desirable to provide an imaging element capable of achieving an improvement in resolution and an improvement in graininess, an electronic device including the imaging element, and a method of driving the imaging element.

[0010] An imaging element according to an embodiment of the present invention includes a first photoelectric conversion unit and a second photoelectric conversion unit, which are stacked in sequence from a light incident side and selectively detect and photoelectrically convert light beams of different wavelength bands, and the second photoelectric conversion unit is arranged at intervals narrower than a pixel pitch of the first photoelectric conversion unit.

[0011] An electronic device according to an embodiment of the present invention includes a plurality of imaging elements for respective pixels, and includes the above-described imaging element according to an embodiment of the present invention as each of the imaging elements.

[0012] In an imaging element including a first photoelectric conversion unit and a second photoelectric conversion unit, the first photoelectric conversion unit and the second photoelectric conversion unit are sequentially stacked from the light incident side and selectively detect and photoelectrically convert light beams of different wavelength bands, wherein the second photoelectric conversion unit is arranged at intervals narrower than the pixel pitch of the first photoelectric conversion unit. A driving method of an imaging element according to an embodiment of the present invention includes: obtaining a color signal of a first light using one pixel of the first photoelectric conversion unit; and obtaining a color signal of a second light of a wavelength band different from the first light by addition among a plurality of the second photoelectric conversion units.

[0013] In the imaging element, electronic device, and method for manufacturing the imaging element according to various embodiments of the present invention, the first photoelectric conversion unit and the second photoelectric conversion unit that selectively detect and photoelectrically convert light beams of different wavelength bands are stacked in sequence from the light incident side, and the pixel pitch of the second photoelectric conversion unit is narrower than the pixel pitch of the first photoelectric conversion unit. This makes it possible to obtain color signals without phase shift from each photoelectric conversion unit in a high-sensitivity mode, for example.

[0014] According to the imaging element, electronic device, and method for manufacturing the imaging element of each embodiment of the present invention, in the first photoelectric conversion unit and the second photoelectric conversion unit that selectively detect and photoelectrically convert light beams of different wavelength bands, the pixel pitch of the second photoelectric conversion unit is arranged at a narrower interval than the first photoelectric conversion unit arranged on the light incident side. This makes it possible to obtain color signals without phase shift from each photoelectric conversion unit in, for example, a high sensitivity mode. Therefore, it is possible to achieve an improvement in resolution and a sense of graininess.

[0015] It should be noted that the effects described here are not necessarily limitative, and may be any effects described in this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a perspective view showing the configuration of a main part of an imaging element according to an embodiment of the present invention.

[0017] Figure 2 It shows Figure 1 Schematic plan view of the configuration of the inorganic photoelectric conversion section relative to the organic photoelectric conversion section of the imaging element shown.

[0018] Figure 3 yes Figure 1 A schematic cross-sectional view showing an example of a specific configuration of an imaging element is shown.

[0019] Figure 4A yes Figure 3 Schematic plan view showing the relationship between an on-chip lens and an organic photoelectric conversion unit of an imaging element.

[0020] Figure 4B yes Figure 3 Schematic plan view showing the relationship between an on-chip lens and an inorganic photoelectric conversion section of an imaging element.

[0021] Figure 5A is a schematic cross-sectional view of light (incident light) entering an organic photoelectric conversion portion through an on-chip lens.

[0022] Figure 5B 2 is a schematic cross-sectional view of light (incident light) entering an inorganic photoelectric conversion unit that acquires a blue signal through an on-chip lens.

[0023] Figure 5C 2 is a schematic cross-sectional view of light (incident light) entering an inorganic photoelectric conversion unit that acquires a red signal through an on-chip lens.

[0024] Figure 6 yes Figure 3 Schematic plan view of an example of the configuration of a unit pixel of an imaging element shown.

[0025] Figure 7 yes Figure 3 Schematic cross-sectional view of an example of a manufacturing process of an imaging element is shown.

[0026] Figure 8 It is the successor Figure 7 Schematic cross-section of the subsequent process.

[0027] Fig.9A is a schematic plan view for explaining a method of driving a green pixel in a high-resolution mode.

[0028] Fig. 9B is a schematic plan view for explaining a method of driving a red pixel in a high-resolution mode.

[0029] Fig. 9C is a schematic plan view for explaining a method of driving a blue pixel in a high-resolution mode.

[0030] Fig.10 is a schematic plan view illustrating a development process in a high-resolution mode.

[0031] Fig.11A is a schematic plan view for explaining a method of driving a green pixel in a high-sensitivity mode.

[0032] Fig. 11B is a schematic plan view for explaining a method of driving a red pixel in a high-sensitivity mode.

[0033] Fig. 11C is a schematic plan view for explaining a method of driving a blue pixel in a high-sensitivity mode.

[0034] Fig.12 is a schematic plan view for explaining the development process in the high-sensitivity mode.

[0035] Fig.13A is a schematic plan view for explaining a method of driving a green pixel in a high-speed mode.

[0036] Fig. 13B is a schematic plan view for explaining a method of driving a red pixel in a high-speed mode.

[0037] Fig. 13C is a schematic plan view for explaining a method of driving a blue pixel in a high-speed mode.

[0038] Fig.14 is a schematic plan view for explaining the thinning process in the high-speed mode.

[0039] Fig.15 is a schematic plan view for explaining the development process in the high-speed mode.

[0040] Fig.16 It is a diagram illustrating FD addition.

[0041] Fig.17 It is a diagram illustrating the addition of numbers.

[0042] Fig.18A is a schematic plane for explaining a high sensitivity mode in a typical imaging element.

[0043] Fig.18B It is the successor Fig.18A The following are schematic plan views for explaining a high sensitivity mode in a typical imaging element.

[0044] Fig.18C It is the successor Fig.18B The following are schematic plan views for explaining a high sensitivity mode in a typical imaging element.

[0045] Fig.18D It is the successor Fig.18C The following are schematic plan views for explaining a high sensitivity mode in a typical imaging element.

[0046] Fig.19 is a schematic cross-sectional view of an example of a specific configuration of an imaging element according to a modification of the present invention.

[0047] Fig. 20 It shows Figure 1 A block diagram of the overall configuration of the imaging element is shown.

[0048] Fig.21 It shows the use of Fig. 20 Functional block diagram of an example of an electronic device (camera) with an imaging element shown.

[0049] Fig. 22 is a block diagram showing an example of a schematic configuration of an in-vivo information acquisition system.

[0050] Fig.23 is a diagram showing an example of a schematic configuration of an endoscopic surgery system.

[0051] Fig.24 is a block diagram showing an example of the functional configuration of a camera head and a camera control unit (CCU).

[0052] Fig.25 is a block diagram showing an example of a schematic configuration of a vehicle control system.

[0053] Fig.26 is a schematic diagram to help explain an example of the installation positions of the vehicle exterior information detection portion and the imaging unit. DETAILED DESCRIPTION

[0054] Hereinafter, an embodiment of the present invention will be given with reference to the accompanying drawings. The following description is only a specific example of the present invention, and the present invention should not be limited to the following aspects. In addition, the present invention is not limited to the arrangement, size, size ratio, etc. of the various components shown in the accompanying drawings. It should be noted that the description will be given in the following order.

[0055] 1. Embodiment (Example of an imaging element in which four pixels of an inorganic photoelectric conversion unit are arranged for one pixel of an organic photoelectric conversion unit)

[0056] 1-1. Structure of imaging element

[0057] 1-2. Method for manufacturing imaging element

[0058] 1-3. Imaging element driving method

[0059] 1-4. Actions and effects

[0060] 2. Modifications

[0061] 3. Application Examples

[0062] <1. Example>

[0063] Figure 1 It is a schematic perspective view of the configuration of the main parts (the organic photoelectric portion 11G and the inorganic photoelectric conversion portions 11B and 11R) of the imaging element (imaging element 1) of the embodiment of the present invention. Figure 2 yes Figure 1 The shown shaped element 1 is a schematic plan view of the configuration of the inorganic photoelectric conversion sections 11B and 11R relative to the organic photoelectric conversion section 11G. Figure 3 Schematically shows Figure 1 The imaging element 1 is an example of a specific cross-sectional structure of the photoelectric element 1 shown. The imaging element 1 is, for example, a back-illuminated (back-light receiving) CCD (charge coupled device) image sensor or a CMOS (complementary metal oxide semiconductor) image sensor (see Fig. 20 ). The imaging element 1 is of a so-called vertical splitting type in which one organic photoelectric conversion portion 11G and two inorganic photoelectric conversion portions 11B and 11R are stacked in a vertical direction and they selectively detect light beams of different wavelength bands to perform photoelectric conversion.

[0064] (1-1. Structure of Imaging Element)

[0065] In the imaging element 1 of the present embodiment, an organic photoelectric converter 11G (first photoelectric converter), an inorganic photoelectric converter 11B (third photoelectric converter), and an inorganic photoelectric converter 11R (second photoelectric converter) are stacked in order from the light incident side, and the inorganic photoelectric converters 11B and 11R are arranged at a pixel pitch (w) narrower than the pixel pitch (W) of the organic photoelectric converter 11G with respect to one pixel of the organic photoelectric converter 11G. Specifically, in the imaging element 1, for example, four (2×2) pixels of the inorganic photoelectric converters 11B and 11R are arranged with respect to one pixel of the organic photoelectric converter 11G. That is, the inorganic photoelectric converters 11B and 11R each have a pixel pitch (w) of, for example, 1 / 2 (w=1 / 2W) with respect to the pixel pitch (W) of the organic photoelectric converter 11G, and are 1 / 4 of the latter in area.

[0066] The organic photoelectric conversion unit 11G and the inorganic photoelectric conversion units 11B and 11R selectively detect light beams of different wavelength bands and perform photoelectric conversion. Specifically, the organic photoelectric conversion unit 11G obtains a green (G) color signal. Due to the difference in absorption coefficients, the inorganic photoelectric conversion units 11B and 11R obtain a blue (B) color signal and a red (R) color signal, respectively. This enables the imaging element 1 to obtain multiple color signals in one pixel without using a color filter.

[0067] It should be noted that in this embodiment, the case where holes in electron-hole pairs generated by photoelectric conversion are read as signal charges (a case where a p-type semiconductor region is used as a photoelectric conversion layer) is described. In addition, in the figure, the "+ (plus sign)" after "p" and "n" indicates that the p-type or n-type impurity concentration is high.

[0068] The organic photoelectric conversion section 11G is provided on the rear surface (first surface 11S1) side of the semiconductor substrate 11. The inorganic photoelectric conversion sections 11B and 11R are respectively formed to be embedded in the semiconductor substrate 11 and are stacked in the thickness direction of the semiconductor substrate 11.

[0069] The semiconductor substrate 11 is composed of, for example, an n-type silicon (Si) substrate, and includes a p-well 61 in a predetermined region. The second surface (front surface of the semiconductor substrate) 11S2 of the p-well 61 is provided with, for example, floating diffusions (floating diffusion layers) FD2 and FD3. In addition, various Trs (transistors) (for example, a TR group 1110 to be described later) (for example, see Figure 6 ). In addition, a multilayer wiring layer 70 is provided on the second surface 11S2 of the semiconductor substrate 11. The multilayer wiring layer 70 has a structure in which, for example, wiring layers 71, 72, and 73 are stacked in an insulating layer 74. In addition, a peripheral circuit (not shown) including a logic circuit and the like is provided in the peripheral portion of the semiconductor substrate 11.

[0070] It should be noted that in Figure 3 , the first surface 11S1 side of the semiconductor substrate 11 is represented by the light incident surface S1, and the second surface 11S2 side of the semiconductor substrate is represented by the wiring layer side S2.

[0071] The inorganic photoelectric conversion parts 11B and 11R are each composed of, for example, a PIN (positive-intrinsic-negative) type photodiode, and each has a pn junction located in a predetermined region of the semiconductor substrate 11. The inorganic photoelectric conversion parts 11B and 11R enable light to be split in the vertical direction by utilizing different wavelength bands that are absorbed corresponding to the incident depth of light in the silicon substrate.

[0072] The inorganic photoelectric conversion unit 11B selectively detects blue light and accumulates signal charges corresponding to the blue color; the inorganic photoelectric conversion unit 11B is installed at a depth that can effectively perform photoelectric conversion on blue light. The inorganic photoelectric conversion unit 11R selectively detects red light and accumulates signal charges corresponding to the red color; the inorganic photoelectric conversion unit 11R is installed at a depth that can effectively perform photoelectric conversion on red light. It should be noted that, for example, blue (B) is a color corresponding to a wavelength band of 450nm to 495nm, and, for example, red (R) is a color corresponding to a wavelength band of 620nm to 750nm. It is sufficient for the inorganic photoelectric conversion units 11B and 11R to be able to detect part or all of the light of their respective wavelength bands.

[0073] Specifically, Figure 3 As shown, each of the inorganic photoelectric conversion section 11B and the inorganic photoelectric conversion section 11R includes, for example, a p+ region serving as a hole accumulation layer and an n region serving as an electron accumulation layer (having a pnp stacking structure). For example, the p+ region of the inorganic photoelectric conversion section 11B is bent along the vertical transistor (vertical transistor Tr1) and joined to the p+ region of the inorganic photoelectric conversion section 11R. In addition, as described above, in the inorganic photoelectric conversion sections 11B and 11R, four inorganic photoelectric conversion sections 11B and four inorganic photoelectric conversion sections 11R are respectively arranged in a 2×2 array with respect to one organic photoelectric conversion section 11G. As will be described later Fig. 9B and Fig. 9C As shown, in the inorganic photoelectric conversion sections 11B and 11R, for example, one floating diffusion FD1 or FD2 is arranged for each 2×2 array.

[0074] A portion of the floating diffusion FD1 is formed in the n-region of the inorganic photoelectric conversion portion 11B provided in the semiconductor substrate 11B, thereby being electrically connected to the inorganic photoelectric conversion portion 11B. For example, the gate wiring layer 64 configuring the vertical transistor Tr1 is electrically connected to the floating diffusion FD1. For example, the floating diffusion FD2 is provided to face the second surface 11S2 of the semiconductor substrate 11; a portion of the floating diffusion FD2 is formed in the n-region of the inorganic photoelectric conversion portion 11R provided in the semiconductor substrate 11, thereby being electrically connected to the inorganic photoelectric conversion portion 11R.

[0075] Besides, as described above, the second surface 11S2 of the semiconductor substrate 11 is provided with, for example, the floating diffusion FD3 and various transistors (such as the vertical transistor Tr1 and the Tr group 1110 to be described later).

[0076] The lower contact 75 is composed of, for example, a doped silicon material such as PDAS (Phosphorus Doped Amorphous Silicon) or a metal material such as aluminum (Al), tungsten (W), titanium (Ti), cobalt (Co), hafnium (Hf), and tantalum (Ta).

[0077] The organic photoelectric conversion unit 11G is provided on one side of the first surface 11S1 of the semiconductor substrate 11. The organic photoelectric conversion unit 11G has a structure in which a lower electrode 15, an organic photoelectric conversion layer 16, and an upper electrode 17 are stacked in this order from the first surface S1 side of the semiconductor substrate 11. For example, the lower electrode 15 is formed separately for each unit pixel P. The organic photoelectric conversion layer 16 and the upper electrode 17 are provided as a continuous layer common to a plurality of unit pixels P (for example, the pixel unit 1a of the imaging element 1 shown in FIG. 18). The organic photoelectric conversion unit 11G is an organic photoelectric conversion element that absorbs a part or all of green light corresponding to a selected wavelength band (for example, a range from 450 nm to 650 nm) and generates electron-hole pairs.

[0078] The interlayer insulating layer 12 and the interlayer insulating layer 14 are stacked in this order, for example, from the semiconductor substrate 11 side, between the first surface 11S1 of the semiconductor substrate 11 and the lower electrode 15. The interlayer insulating layer 12 has, for example, a structure in which a layer 12A having a fixed charge (fixed charge layer) and a dielectric layer 12B having an insulating property are stacked. A protective layer 18 is provided on the upper electrode 17. An on-chip lens layer 19 constituting an on-chip lens 19L and also serving as a flattening layer is arranged on the protective layer 18.

[0079] A through electrode 63 is provided between the first surface 11S1 and the second surface 11S2 of the semiconductor substrate 11. The organic photoelectric conversion section 11G is respectively bonded to the floating diffusion FD3 and the gate (not shown) of the amplifier transistor AMP via the through electrode 63. This enables the imaging element 1 to smoothly transfer the charge generated in the organic photoelectric conversion section 11G on the first surface 11S1 side of the semiconductor substrate 11 to the second surface 11S2 side of the semiconductor substrate 11 through the through electrode 63, and thus enhance the characteristics.

[0080] The through electrode 63 is provided for each organic photoelectric converter 11G of the imaging element 1, for example. The through electrode 63 serves as a connector between the organic photoelectric converter 11G and the floating diffusion FD3 and the gate of the amplifier transistor AMP, and serves as a transfer path of charges generated in the organic photoelectric converter 11G.

[0081] The lower end of the through electrode 63 is bonded to, for example, a connection portion 71A in the wiring layer 71, and the connection portion 71A and the gate of the amplifier transistor AMP are bonded to each other through, for example, a contact portion (not shown) having a configuration similar to that of the lower contact portion 75. The connection portion 71A and the floating diffusion FD3 are connected to the lower electrode 15 via the lower contact portion 75. Note that Figure 1 , the through-electrode 63 is illustrated as having a columnar shape, but this is not limitative; for example, the through-electrode 63 may have a conical shape.

[0082] Although not shown, it is preferable to arrange the reset gate of the reset transistor RST adjacent to the floating diffusion FD3. This enables the charge accumulated in the floating diffusion FD3 to be reset by the reset transistor RST.

[0083] In the imaging element 1, light incident on the organic photoelectric conversion section 11G from the upper electrode 17 side is absorbed by the organic photoelectric conversion layer 16. The excitons thus generated move to the interface between the electron donor and the electron acceptor constituting the organic photoelectric conversion layer 16, and undergo exciton separation, i.e., dissociate into electrons and holes. The charges (electrons and holes) generated here are transferred to different electrodes by diffusion due to the difference in carrier concentration or by the internal electric field caused by the difference in work function between the anode (here, the lower electrode 15) and the cathode (here, the upper electrode 17), and are detected as photocurrent. In addition, the application of an electric potential between the lower electrode 15 and the upper electrode 17 makes it possible to control the transmission direction of electrons and holes.

[0084] Hereinafter, a description will be given of the materials, configurations, etc. of the respective parts.

[0085] The organic photoelectric conversion section 11G includes an organic photoelectric conversion layer 16, which contains a p-type semiconductor and an n-type semiconductor and has a bulk heterojunction structure in the layer. The bulk heterojunction structure is a p / n junction plane formed by mixing a p-type semiconductor with an n-type semiconductor. The organic photoelectric conversion section 11G is an organic photoelectric conversion element that absorbs a part or all of light corresponding to a selected wavelength band (for example, a range from 450nm to 750nm) and generates electron-hole pairs. As described above, the organic photoelectric conversion section 11G is composed of, for example, a lower electrode 15 and an upper electrode 17 arranged to be opposite to each other, and an organic photoelectric conversion layer 16 disposed between the lower electrode 15 and the upper electrode 17.

[0086] The lower electrode 15 is arranged in a region facing and covering the light receiving surface of four inorganic photoelectric conversion units 11B and four inorganic photoelectric conversion units 11R formed in the semiconductor substrate 11, and the four inorganic photoelectric conversion units 11B and the four inorganic photoelectric conversion units 11R are arranged in a 2×2 form, respectively. The lower electrode 15 is composed of a metal oxide having light transmittance. Examples of metal atoms of the metal oxide as a material constituting the lower electrode 15 include tin (Sn), zinc (Zn), indium (In), silicon (Si), zirconium (Zr), aluminum (Al), gallium (Ga), tungsten (W), chromium (Cr), cobalt (Co), nickel (Ni), tantalum (Ta), niobium (Nb) and molybdenum (Mo). Examples of metal oxides containing one or more of the above metal atoms include ITO (indium tin oxide). However, in addition to ITO, a material based on tin oxide (SnO2) doped with impurities, or a material based on zinc oxide in which aluminum zinc oxide is doped with impurities can also be used as a material constituting the lower electrode 15. Examples of zinc oxide-based materials include aluminum zinc oxide (AZO) doped with aluminum (Al) as an impurity, gallium zinc oxide (GZO) doped with gallium (Ga), and indium zinc oxide (IZO) doped with indium (In). In addition, in addition to the above, CuI, InSbO4, ZnMgO, CuInO2, MgIn2O4, CdO, ZnSnO3, etc. can be used.

[0087] The organic photoelectric conversion layer 16 converts light energy into electrical energy. The organic photoelectric conversion layer 16 includes, for example, two or more organic semiconductor materials (p-type semiconductor material and n-type semiconductor material) that are used as p-type semiconductors or n-type semiconductors, respectively. The organic photoelectric conversion layer 16 includes a junction surface (p / n junction plane) between the p-type semiconductor material and the n-type semiconductor material within the layer. The p-type semiconductor relatively acts as an electron donor, and the n-type semiconductor relatively acts as an electron acceptor. The organic photoelectric conversion layer 16 is provided with a field in which excitons generated when light is absorbed are separated into electrons and holes; specifically, the excitons are separated into electrons and holes at the interface (p / n junction plane) between the electron donor and the electron acceptor.

[0088] In addition to the p-type semiconductor material and the n-type semiconductor material, the organic photoelectric conversion layer 16 may include a semiconductor material that performs photoelectric conversion on light of a predetermined wavelength band while transmitting light of other wavelength bands, that is, a so-called dye material. In the case where the organic photoelectric conversion layer 16 is formed using a p-type semiconductor material, an n-type semiconductor material, and a dye material, the p-type semiconductor material and the n-type semiconductor material are preferably materials having light transmittance in the visible region (e.g., 450nm to 800nm), respectively. The organic photoelectric conversion layer 16 has a thickness of, for example, 50nm to 500nm.

[0089] Examples of organic semiconductor materials constituting the organic photoelectric conversion layer 16 include quinacridone, chloroboron subphthalocyanine, pentacene, benzothienobenzothiophene, fullerene, and their derivatives. The organic photoelectric conversion layer 16 is composed of a combination of two or more of the above organic semiconductor materials. The above organic semiconductor materials act as a p-type semiconductor or an n-type semiconductor according to their combination.

[0090] It should be noted that there is no specific restriction on the organic semiconductor material constituting the organic photoelectric conversion layer 16. In addition to the above-mentioned organic semiconductor materials, for example, any one of naphthalene, anthracene, phenanthrene, tetraene, pyrene, perylene and fluoranthene or their derivatives can be appropriately used. Alternatively, polymers such as phenylacetylene, fluorene, carbazole, indole, pyrene, pyrrole, pyridine, thiophene, acetylene and diacetylene and their derivatives can be used. In addition, condensed polycyclic aromatic compounds and chain compounds in which aromatic rings or heterocyclic compounds are condensed can be preferably used, such as metal complex dyes, cyanine-based dyes, merocyanine-based dyes, phenylxanthene-based dyes, triphenylmethane-based dyes, rhodanine-based dyes, xanthene-based dyes, macrocyclic azacyclic dyes, azulene-based dyes, naphthoquinones, anthraquinone-based dyes, anthracene and pyrene. Alternatively, two nitrogen-containing heterocyclic rings having a squaryl cyanine group and a croconic methine group as a bonding chain, or a cyanine-like dye linked by a squaryl cyanine group and a croconic methine group, such as quinoline, benzothiazole, and benzoxazole, etc., can be preferably used. It should be noted that as the above-mentioned metal complex dye, a dithiol metal complex dye, a metal phthalocyanine dye, a metal porphyrin dye, or a ruthenium complex dye is preferred; however, this is not restrictive.

[0091] The upper electrode 17 is composed of a conductive film having light transmittance similar to the lower electrode 15. In the imaging element 1, the upper electrode 17 may be provided individually for each unit pixel P, or the upper electrode 17 may be formed as a common electrode for each unit pixel P. The upper electrode 17 has a thickness of, for example, 10 nm to 200 nm.

[0092] It should be noted that other layers may be provided between the organic photoelectric conversion layer 16 and the lower electrode 15 and between the organic photoelectric conversion layer 16 and the upper electrode 17. Specifically, for example, an underlying layer, a hole transport layer, an electron blocking layer, an organic photoelectric conversion layer 16, a hole blocking layer, a buffer layer, an electron transport layer, and a work function adjustment layer may be stacked in sequence from the lower electrode 15 side.

[0093] The fixed charge layer 12A may be a film having a fixed positive charge or a film having a fixed negative charge. Examples of materials of the film having a fixed negative charge include hafnium oxide (HfO2), aluminum oxide (Al2O3), zirconium oxide (ZrO2), tantalum oxide (Ta2O5) and titanium oxide (TiO2). In addition, as materials other than the above-mentioned materials, lanthanum oxide, praseodymium oxide, cerium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, aluminum nitride film, hafnium oxynitride film or aluminum oxynitride film may be used.

[0094] The fixed charge layer 12A may have a structure in which two or more films are stacked. This makes it possible to further enhance the function as a hole accumulation layer, for example, in the case of a film having negative fixed charge.

[0095] The material of dielectric layer 12B is not particularly limited, and dielectric layer 12B is formed of, for example, a silicon oxide film, a TEOS film, a silicon nitride film, a silicon nitride oxide film, or the like.

[0096] Similar to the lower contact portion 75, the pad portions 13A and 13C and the upper contact portion 13B are respectively composed of a doped silicon material (such as PDAS (phosphorus-doped amorphous silicon) or a metal material such as aluminum (Al), tungsten (W), titanium (Ti), cobalt (Co), hafnium (Hf) or tantalum (Ta).

[0097] The interlayer insulating layer 14 is composed of, for example, a single-layer film of one of silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), or the like, or alternatively a stacked film of two or more thereof.

[0098] The protective layer 18 is made of a light-transmitting material and is, for example, a single-layer film of one of silicon oxide, silicon nitride and silicon oxynitride, or alternatively a laminated film of two or more thereof. The protective layer 18 has a thickness of, for example, 100 nm to 30,000 nm.

[0099] The on-chip lens layer 19 is formed on the protective layer 18 to cover the entire surface of the protective layer 18. A plurality of on-chip lenses (microlenses) 19L are provided on the front surface of the on-chip lens layer 19. The on-chip lenses 19L collect light incident from above onto the light receiving surfaces of each of the organic photoelectric conversion unit 11G and the inorganic photoelectric conversion units 11B and 11R.

[0100] In the imaging element 1, as described above, four inorganic photoelectric conversion sections 11B (blue pixels Pb) arranged in a 2×2 manner and four inorganic photoelectric conversion sections 11R (red pixels Pr) arranged in a 2×2 manner are arranged with respect to one organic photoelectric conversion section 11G (green pixel Pg). Figure 4A and Figure 4B As shown, one organic photoelectric conversion portion 11G (one green pixel Pg), four inorganic photoelectric conversion portions 11B, 11R (four blue pixels Pb and four red pixels Pr) are vertically arranged on the on-chip lens 19L.

[0101] FIG. 5A to FIG. 5C Incident light (L) associated with the organic photoelectric converter 11G and the inorganic photoelectric converters 11B and 11R are schematically shown, respectively. In the present embodiment, as described above, one organic photoelectric converter 11G, four inorganic photoelectric converters 11B, and four inorganic photoelectric converters 11R are arranged with one on-chip lens 19L. This enables the inorganic photoelectric converters 11B and 11R to obtain signals for phase difference detection.

[0102] Furthermore, in the present embodiment, the multilayer wiring layer 70 is formed on the second surface 11S2 side of the semiconductor substrate 11. This makes it possible to arrange the light receiving surfaces of the organic photoelectric conversion section 11G and the inorganic photoelectric conversion sections 11B and 11R close to each other, thereby reducing the difference in sensitivity between colors due to the F value of the on-chip lens 19L.

[0103] Figure 6 1 is a plan view of a configuration example of an imaging element 1 in which a plurality of photoelectric conversion sections (for example, the above-described inorganic photoelectric conversion sections 11B and 11R and the organic photoelectric conversion section 11G) to which the technology according to the present invention is applied are stacked. Figure 6 For example, the structure Fig. 20 1 is an example of a planar configuration of a unit pixel P of a pixel section 1 a shown, and represents an example of a configuration of an imaging element 1 in which a plurality of photoelectric conversion sections to which the technology according to the present invention is applied are stacked.

[0104] The unit pixel P includes a photoelectric conversion region 1100, in which a red photoelectric conversion unit ( Figure 3 Inorganic photoelectric conversion unit 11R in the blue photoelectric conversion unit ( Figure 3 The inorganic photoelectric conversion unit 11B) and the green photoelectric conversion unit ( Figure 3 The organic photoelectric conversion unit 11G in Figure 6 ) For example, in the order of the green photoelectric conversion unit, the blue photoelectric conversion unit, and the red photoelectric conversion unit, from the light receiving surface side ( Figure 3The imaging element 1 performs spectroscopy in the vertical direction in one unit pixel P, that is, spectroscopy is performed on the R, G, and B light beams in the respective layers stacked in the photoelectric conversion region 1100 as the red photoelectric conversion portion, the green photoelectric conversion portion, and the blue photoelectric conversion portion.

[0105] Tr group 1110, Tr group 1120 and Tr group 1130 are formed at the periphery of the photoelectric conversion region 1100. Tr group 1110 outputs a signal charge corresponding to the R light generated and accumulated in the red photoelectric conversion portion as a pixel signal. Tr group 1110 is composed of a transfer Tr (MOS FET) 1111, a reset Tr 1112, an amplification Tr 1113 and a selection Tr 1114. Tr group 1120 outputs a signal charge corresponding to the B light generated and accumulated in the blue photoelectric conversion portion as a pixel signal. Tr group 1120 is composed of a transfer Tr 1121, a reset Tr 1122, an amplification Tr 1123 and a selection Tr 1124. Tr group 1130 outputs a signal charge corresponding to the G light generated and accumulated in the green photoelectric conversion portion as a pixel signal. Tr group 1130 includes a transfer Tr 1131, a reset Tr 1132, an amplification Tr 1133 and a selection Tr 1134.

[0106] The transfer Tr 1111 is composed of a gate G, a source / drain region S / D, and an FD (floating diffusion) 1115 (composed of a source / drain region). The transfer Tr 1121 is composed of a gate G, a source / drain region S / D, and FD1125. The transfer Tr 1131 is composed of a gate G, a green photoelectric conversion portion of the photoelectric conversion region 1100 (connected to the source / drain region S / D), and FD 1135. It should be noted that the source / drain region of the transfer Tr 1111 is connected to the red photoelectric conversion portion of the photoelectric conversion region 1100, and the source / drain region S / D of the transfer Tr 1121 is connected to the blue photoelectric conversion portion of the photoelectric conversion region 1100.

[0107] The reset Tr 1112, reset Tr 1132 and reset Tr 1122, the amplification Tr 1113, amplification Tr 1133 and amplification Tr 1123, and the selection Tr 1114, selection Tr 1134 and selection Tr 1124 are respectively constituted of a pair of source / drain regions S / D with the gate G inserted therebetween.

[0108] FD1115, FD1135, and FD1125 are connected to the source / drain regions S / D serving as sources of the reset Tr 1112, reset TrTr1132, and reset TrTr1122, respectively, and are connected to the gates G of the amplification Tr 1113, amplification Tr 1133, and amplification Tr 1123, respectively. The power supply Vdd is connected to the common source / drain region S / D of each of the reset Tr1112, amplification Tr 1113, reset Tr 1132, amplification Tr 1133, reset Tr1122, and amplification Tr 1123. VSL (vertical signal line) is connected to the respective source / drain regions S / D serving as sources of the selection Tr1114, selection Tr 1134, and selection Tr 1124.

[0109] The technology according to the present invention is applicable to the above-mentioned photoelectric conversion element.

[0110] (1-2. Method for manufacturing imaging element)

[0111] The imaging element 1 of this embodiment can be manufactured, for example, as follows.

[0112] Figure 7 and Figure 8 The manufacturing method of the imaging element 1 is shown in the order of steps. First, Figure 7 As shown, a p-well 61 as a well of the first conductivity type is formed in the semiconductor substrate 11, and inorganic photoelectric conversion parts 11B and 11R of the second conductivity type (e.g., n-type) are formed in the p-well 61. A p+ region is formed in the vicinity of the first surface 11S1 of the semiconductor substrate 11. An n+ region serving as a floating diffusion FD1 is formed in the semiconductor substrate 11 so that part thereof is buried.

[0113] Still like Figure 7 As shown, on the second surface 11S2 of the semiconductor substrate 11, n+ regions as the floating diffusion FD2 and the floating diffusion FD3 are formed, and then, the gate insulating layer 62 and the gate wiring layer 64 including the respective gates of the above-mentioned Tr group 1110 are formed. Thus, the vertical transistor Tr1 and the various Tr groups 1110 are formed. In addition, a multilayer wiring layer 70 including a lower contact portion, wiring layers 71 to 73 including a connection portion 71A, and an insulating layer 74 is formed on the second surface 11S2 of the semiconductor substrate 11.

[0114] For example, an SOI (Silicon On Insulator) substrate is used as a base of the semiconductor substrate 11, in which the semiconductor substrate 11, an embedded oxide film (not shown), and a holding substrate (not shown) are stacked. Figure 7 Not shown in the figure, the embedded oxide film and the holding substrate are connected to the first surface 11S1 of the semiconductor substrate 11. After the ion implantation, annealing treatment is performed.

[0115] Next, a support substrate (not shown) or another semiconductor substrate is connected to the second surface 11S2 side (multilayer wiring layer 70 side) of the semiconductor substrate 11, and the substrate is turned upside down. Next, the semiconductor substrate 11 is separated from the embedded oxide film of the SOI substrate and the holding substrate to expose the first surface 11S1 of the semiconductor substrate 11. The above steps can be performed by techniques such as ion implantation and chemical vapor deposition (CVD) used in conventional CMOS processing.

[0116] Next, if Figure 8 As shown, the semiconductor substrate 11 is processed from the first surface 11S1 side, for example, by dry etching, to form the annular opening 63H. Figure 6 As shown, in terms of depth, the opening 63H penetrates from the first surface 11S1 to the second surface 11S2 of the semiconductor substrate 11 , and reaches, for example, the connection portion 71A.

[0117] Then, if Figure 8 As shown, for example, a fixed negative charge layer 12A is formed on the first surface 11S1 of the semiconductor substrate 11 and the side surface of the opening 63H. Two or more films can be stacked as the fixed negative charge layer 12A. This enables the fixed negative charge layer 12A to further enhance its function as a hole accumulation layer. After the fixed negative charge layer 12A is formed, a dielectric layer 12B is formed.

[0118] Next, a conductor is buried in the opening 63H to form the through electrode 63. In addition to doped silicon materials such as PDAS (phosphorus doped amorphous silicon) as the through electrode, for example, metal materials such as aluminum (Al), tungsten (W), titanium (Ti), cobalt (Co), hafnium (Hf), and tantalum (Ta) can also be used.

[0119] Next, after forming a pad section 13A on the through hole 63, an interlayer insulating layer 14 is formed on the dielectric layer 12B and the pad section 13A. In the interlayer insulating layer 14, an upper contact section 13B and a pad section 13C electrically connected to the lower electrode 15 and the through electrode 63 (specifically, the pad section 13A of the through electrode 63) are provided on the pad section 13A.

[0120] Next, the lower electrode 15, the organic photoelectric conversion layer 16, the upper electrode 17 and the protective layer 18 are sequentially formed on the interlayer insulating layer 14. Finally, the on-chip lens layer 19 including a plurality of on-chip lenses 19L on its surface is arranged. Thus, the Figure 3 The imaging element 1 is shown.

[0121] It should be noted that, in the case where another organic layer (e.g., an electron blocking layer, etc.) is formed above or below the organic photoelectric conversion layer 16, it is desirable to continuously form the other organic layer in a vacuum process (by vacuum continuous processing). In addition, the method of forming the organic photoelectric conversion layer 16 is not necessarily limited to using a vacuum deposition method, but other methods such as spin coating technology, printing technology, etc. may be used.

[0122] (1-3. Method of driving imaging element)

[0123] In the imaging element 1, when light enters the organic photoelectric conversion unit 11G through the on-chip lens 19L, the light sequentially passes through the organic photoelectric conversion unit 11G, the inorganic photoelectric conversion units 11B and 11R, and each light of green, blue and red is electrically converted during the passage. Hereinafter, the acquisition operation of the signal of each color will be described.

[0124] (Acquisition of Green Signal by Organic Photoelectric Conversion Section 11G)

[0125] The green light that has entered the imaging element 1 is first selectively detected by the organic photoelectric conversion portion 11G and is photoelectrically converted.

[0126] The organic photoelectric conversion portion 11G is connected to the gate G of the amplifying Tr 1113 and the floating diffusion FD3 through the through electrode 63. Therefore, holes in the electron-hole pairs generated in the organic photoelectric conversion portion 11G are extracted from the lower electrode 15 side, transferred to the second surface 11S2 side of the semiconductor substrate 11 through the through electrode 63, and accumulated in the floating diffusion FD3. At the same time, the amount of charge generated in the organic photoelectric portion 11G is modulated into a voltage by the amplifying Tr 1113.

[0127] In addition, the gate G of the reset Tr 1112 is arranged adjacent to the floating diffusion FD3 . Therefore, the charge accumulated in the floating diffusion FD3 is reset by the reset Tr 1112 .

[0128] Here, the organic photoelectric conversion section 11G is connected not only to the amplification Tr 1113 but also to the floating diffusion FD3 through the through electrode 63 , thus enabling the charge accumulated in the floating diffusion FD3 to be easily reset by the reset Tr 1112 .

[0129] On the other hand, in the case where the through electrode 63 and the floating diffusion FD3 are not connected to each other, it is difficult to reset the charges accumulated in the floating diffusion FD3, resulting in a large voltage being applied to pull the charges out to the upper electrode 17 side. Therefore, there is a possibility that the organic photoelectric conversion layer 16 is destroyed. In addition, a structure capable of achieving reset in a short time leads to an increase in dark noise, resulting in a trade-off, and therefore such a structure is difficult.

[0130] (Acquisition of Blue Signal and Red Signal by Inorganic Photoelectric Conversion Sections 11B and 11R)

[0131] Next, among the light transmitted through the organic photoelectric conversion section 11G, the blue light and the red light are absorbed by the inorganic photoelectric conversion section 11B and the inorganic photoelectric conversion section 11R in sequence and photoelectrically converted. In the inorganic photoelectric conversion section 11B, electrons corresponding to the incident blue light are accumulated in the n-type region of the organic photoelectric conversion section 11B, and the accumulated electrons are transferred to the floating diffusion FD1. Similarly, in the inorganic photoelectric conversion section 11R, electrons corresponding to the incident red light are accumulated in the n-type region of the inorganic photoelectric conversion section 11R, and the accumulated electrons are transferred to the floating diffusion FD2 by the transfer transistor Tr.

[0132] The imaging element 1 of this embodiment has a plurality of operation modes, for example, three operation modes of high resolution mode, high sensitivity mode and high speed mode. In each operation mode, in the organic photoelectric conversion section 11G and the inorganic photoelectric conversion sections 11B and 11R, R / G / B signals are acquired as follows.

[0133] The high resolution mode is described below. Fig.9A As shown in FIG. 1 , in the organic photoelectric conversion section 11G that acquires the green signal, the signal charge is read from each of all the green pixels Pg. Fig. 9B and Fig. 9C As shown, in the inorganic photoelectric conversion unit 11B for acquiring a blue signal and the inorganic photoelectric conversion unit 11R for acquiring a red signal, FD addition is performed using 4 (2×2) pixels as a unit U. Then, development processing is performed. In high-resolution mode, phase-matched signals can be obtained among the green pixel Pg, 2×2 blue pixels Pb, and 2×2 red pixels Pr. Therefore, in the unit pixel P, R / G / B signals without phase shift can be obtained without signal processing.

[0134] The high sensitivity mode is explained below. Fig.11A As shown in FIG. 1 , in the organic photoelectric conversion section 11G that acquires the green signal, the signal charge is read from each of all the green pixels Pg. Fig. 11B and Fig. 11CAs shown, in the inorganic photoelectric conversion unit 11B for acquiring a blue signal and the inorganic photoelectric conversion unit 11R for acquiring a red signal, 16 (4×4) pixels (blue pixels Pb and red pixels Pr) are used as a unit U to perform digital addition. At this time, the unit U of the inorganic photoelectric conversion unit 11B and the unit U of the inorganic photoelectric conversion unit 11R for acquiring a red signal are composed of 4×4 pixels offset from each other by 2×2 pixels. Then, a development process is performed. As described above, the unit U of the inorganic photoelectric conversion unit 11B and the unit U of the inorganic photoelectric conversion unit 11R for acquiring a red signal are configured to be offset from each other by 2×2 pixels. Therefore, in the high-sensitivity mode, among the unit pixels P, there is a unit pixel P that does not have information of the blue pixel Pb or the red pixel Pr, or a unit pixel P that does not have information of both the blue pixel Pb and the red pixel Pr. Therefore, in the development process of the high-sensitivity mode, as Fig.12 As shown, for example, a unit pixel P having a green signal and a blue signal supplements a red signal from surrounding unit pixels P having a green signal and a red signal. This allows the R / G / B signals to have no phase shift in the high sensitivity mode.

[0135] The high-speed mode is described below. Fig.13A As shown in FIG. 1 , in the organic photoelectric conversion section 11G that acquires a green signal, signal charges are read from each of all green pixels Pg. Fig. 13B and Fig. 13C As shown, in the inorganic photoelectric conversion section 11B for acquiring a blue signal and the inorganic photoelectric conversion section 11R for acquiring a red signal, digital addition is performed using 4 (2×2) pixels as one unit U. In high-speed mode, thinning processing is then performed, and as Fig.14 As shown, the green signal, the blue signal and the red signal are acquired in a Bayer form. Finally, each unit pixel P is developed, which makes the R / G / B signals have no phase shift in the high-speed mode.

[0136] It should be noted that the switching of the addition mode used in each of the above-mentioned operation modes can be performed as follows. In the imaging element 1A of the present embodiment, the switches SW1, SW2, SW3, and SW4 are respectively connected to the four blue pixels Pb and the four red pixels Pr (P1, P2, P3, and P4) provided in one unit pixel P. In the FD addition mode used in the high-resolution mode and the high-speed mode, as shown in FIG. Fig.16 As shown, the switches SW1, SW2, SW3 and SW4 respectively connected to the color pixels P1, P2, P3 and P4 are turned on so that the signals of the four color pixels P1, P2, P3 and P4 are output as one pixel. In the digital addition mode used in the high sensitivity mode, as shown in FIG. Fig.17As shown, one of the switches SW1, SW2, SW3 and SW4 respectively coupled to the color pixels P1, P2, P3 and P4 is turned on, and the remaining three switches are turned off so that signals are read for each of the color pixels P1, P2, P3 and P4, and then output as four pixels. Therefore, the signals of these four pixels are added in the ISP of the next stage.

[0137] (1-4. Actions and Effects)

[0138] As described above, solid-state imaging devices such as CMOS image sensors or CCD image sensors are expected to have enhanced sensitivity. To this end, for example, a so-called vertical beam splitting solid-state imaging device has been developed in which an organic photoelectric conversion unit having an organic photoelectric conversion film and two inorganic photoelectric conversion units having pn junctions in semiconductor substrates are stacked. In this vertical beam splitting solid-state imaging device, R / G / B signals can be acquired from one pixel, thereby enabling a higher resolution than an imaging device in which individual color pixels (red pixels, green pixels, and blue pixels) of primary color filters of red, green, and blue are arranged in a two-dimensional manner.

[0139] However, in the solid-state imaging device with vertical beam splitting as described above, color mixing in the RB spectrum is added in the semiconductor substrate. Therefore, there is a problem of increased color noise, and the noise is amplified in the dark state, thereby greatly deteriorating the graininess. Examples of methods for improving the graininess include a method of using a high sensitivity mode.

[0140] like Fig.18A As shown, in the high sensitivity mode of the typical imaging element 1000, the signal charge is first read from each of all the green pixels Pg of the organic photoelectric conversion unit 1011G that acquires the green signal. In each of the inorganic photoelectric conversion units 11B that acquires the blue signal and the inorganic photoelectric conversion unit 11R that acquires the red signal, digital addition is performed using 4 (2×2) pixels (blue pixels Pb and red pixels Pr) as a unit U. At this time, each unit U of the inorganic photoelectric conversion unit 11B and the inorganic photoelectric conversion unit 11R is composed of 2×2 pixels that are offset from each other by 1×1 pixels. Then, as Fig.18B The pinning process is performed as shown, and then the demosaicing process is performed between the blue pixel Pb and the red pixel Pr to obtain Fig.18C The RB signal is shown in Figure 1. Therefore, Fig.18D As shown, in the imaging element 1000, a phase shift occurs during operation of a green signal (G signal) and an RB signal.

[0141] In contrast, in the imaging element 1 of the present embodiment, the inorganic photoelectric converters 11B and 11R are formed to have a pixel pitch (w) narrower than the pixel pitch (W) of the organic photoelectric converter 11G with respect to one pixel of the organic photoelectric converter 11G. Specifically, for example, four pixels of a 2×2 array of the inorganic photoelectric converters 11B and 11R are arranged with respect to one pixel of the organic photoelectric converter 11G. In the imaging element 1, during the above-mentioned three operation modes (high-resolution mode, high-sensitivity mode, and high-speed mode), a green signal is acquired from one pixel of the organic photoelectric converter 11G (green pixel Pg), while a blue signal and a red signal are obtained by adding signals of 2×2 4 pixels or 4×4 16 pixels of the inorganic photoelectric converter 11B (blue pixel Pb) and the inorganic photoelectric converter 11R (red pixel Pr), respectively. Therefore, R / G / B signals without phase shift can be obtained.

[0142] As described above, in the imaging element 1 of the present embodiment, 4 (2×2) pixels of the inorganic photoelectric conversion units 11B and 11R are arranged respectively with respect to one pixel of the organic photoelectric conversion unit 11G. In each operation mode, with respect to one pixel of the organic photoelectric conversion unit 11G (green pixel Pg) that obtains a green signal, a blue signal and a red signal are obtained by adding 2×2 4 pixels or 4×4 16 pixels of the inorganic photoelectric conversion unit 11B (blue pixel Pb) and the inorganic photoelectric conversion unit 11R (red pixel Pr). In particular, in the high sensitivity mode, a blue signal and a red signal are obtained respectively by adding signals from a total of 16 pixels of 4×4, thereby enabling the graininess to be reduced in a dark state. That is, an imaging element that achieves improved resolution and improved graininess can be provided.

[0143] Next, a modification of the present invention will be described. Hereinafter, components similar to those of the above-described embodiment are denoted by the same reference numerals, and description thereof is appropriately omitted.

[0144] <2. Modifications>

[0145] Fig.19 1 shows a cross-sectional structure of an imaging element (imaging element 1B) according to a modification of the present invention. Similar to the photoelectric conversion element 10A, the imaging element 1B constitutes a CCD image sensor or a CMOS image sensor of a back-illuminated type (back-light receiving type) (see Fig.21). Similar to the above-mentioned imaging element 1A, the imaging element 1B is a vertical splitting imaging element in which one organic photoelectric conversion unit 20 and two inorganic photoelectric conversion units 11B and 11R that selectively detect light beams of different wavelength bands for photoelectric conversion are stacked in the vertical direction. The imaging element 1B of this modification is different from the aforementioned embodiment in that the lower electrode 21 includes a plurality of electrodes (a readout electrode 21A and an accumulation electrode 21B).

[0146] Similar to the imaging element 1A in the above embodiment, the organic photoelectric conversion section 20 is provided on the back surface (first surface 11S1) side of the semiconductor substrate 11. The inorganic photoelectric conversion sections 11B and 11R are respectively formed to be embedded in the semiconductor substrate 11 and stacked in the thickness direction of the semiconductor substrate 11.

[0147] The organic photoelectric conversion unit 20 has, for example, a structure in which a lower electrode 21, an organic photoelectric conversion layer 16, and an upper electrode 17 are stacked in order from the first surface 11S1 side of the semiconductor substrate 11. It should be noted that an insulating layer 22 is provided between the lower electrode 21 and the charge accumulation layer 23. For example, the lower electrode 21 is formed separately for each imaging element 1B, and is composed of a readout electrode 21A and an accumulation electrode 21B, and the readout electrode 21A and the accumulation electrode 21B are separated from each other by the insulating layer 22 inserted therebetween, and their detailed description will be given later. The insulating layer 22 on the readout electrode 21A is provided with an opening 22H, and the readout electrode 21A and the charge accumulation layer 23 are electrically connected via the opening 22H.

[0148] It should be noted that in Fig.19 In the example shown, the charge accumulation layer 23, the organic photoelectric conversion layer 16, and the upper electrode 17 are formed separately for each imaging element 1B, but, for example, similar to the above-mentioned imaging element 1A, it can be set as a continuous layer shared by a plurality of imaging elements 1B. For example, similar to the first embodiment, a fixed charge layer 12A, a dielectric layer 12B, and an interlayer insulating layer 14 are provided between the first surface 11S1 of the semiconductor substrate 11 and the lower electrode 21. A protective layer 18 including a light shielding film 51 is provided on the upper electrode 17. Optical components such as an on-chip lens layer 19 including an on-chip lens 19L are arranged on the protective layer 18.

[0149] As described above, the lower electrode 21 is composed of the readout electrode 21A and the accumulation electrode 21B, which are formed separately, and voltages are applied to each other independently. The readout electrode 21A is used to transfer the charges (here, electrons) generated in the organic photoelectric conversion layer 16 to the floating diffusion FD3, and, for example, is joined to the floating diffusion FD3 through the upper first contact portion 24A, the pad portion 39A, the through electrode 63, the connection portion 71A, and the lower contact portion 75. The accumulation electrode 21B is provided to accumulate electrons as signal charges among the charges generated in the organic photoelectric conversion layer 16 in the charge accumulation layer 23, and to transfer the accumulated electrons to the readout electrode 21A. The accumulation electrode 21B is provided in a region that faces and covers the light receiving surfaces of the inorganic photoelectric conversion components 11B and 11R formed in the semiconductor substrate 11. The accumulation electrode 21B is preferably larger than the readout electrode 21A, which enables a large amount of charge to be accumulated in the charge accumulation layer 23.

[0150] As described above, in the present modification, the lower electrode 21 is divided into the readout electrode 21A and the accumulation electrode 21B so that they are applied with voltage independently of each other. This enables the imaging element 1B to accumulate the charge generated in the organic photoelectric conversion layer 16 in the charge accumulation layer 23 provided between the lower electrode 21 and the organic photoelectric conversion layer 16, and enables the accumulated charge to be appropriately read into the floating diffusion FD3 via the readout electrode 21A. Therefore, the charge accumulation portion can be completely depleted at the start of exposure, thereby achieving an effect of improving the quality of captured images in addition to the effects of the above-described embodiment.

[0151] <3. Application Examples>

[0152] (Application Example 1)

[0153] Fig. 20 The overall configuration of an imaging element 1 in which the imaging element 1 in the above-described embodiment is used as each pixel is shown. The imaging element 1 is a CMOS imaging sensor. The imaging element 1 has a pixel section 1a as an imaging area on a semiconductor substrate 11, and includes a peripheral circuit section 130 composed of, for example, a row scanning section 131, a horizontal selection section 133, a column scanning section 134, and a system control section 132 in the peripheral area of ​​the pixel section 1a.

[0154] The pixel section 1a includes, for example, a plurality of unit pixels P (for example, corresponding to the green pixels Pg of the imaging element 1) arranged in a two-dimensional matrix. For the unit pixel P, for example, the pixel drive line Lread (specifically, the row selection line and the reset control line) is wired in units of pixel rows, and the vertical signal line Lsig is wired in units of pixel columns. The pixel drive line Lread sends a drive signal for reading a signal from a pixel. One end of the pixel drive line Lread is connected to an output terminal corresponding to each row in the row scanning section 131.

[0155] The row scanning section 131 is composed of a shift register, an address decoder, etc. The row scanning section 131 is, for example, a pixel driver that drives each unit pixel P in the pixel section 1a in units of rows. Signals output from each unit pixel P in a pixel row selectively scanned by the row scanning section 131 are provided to the horizontal selection section 133 via the corresponding vertical signal line Lsig. The horizontal selection section 133 is composed of an amplifier, a horizontal selection switch, etc. provided for each vertical signal line Lsig.

[0156] The column scanning section 134 is composed of a shift register, an address decoder, etc. The column scanning section 134 sequentially drives each horizontal selection switch in the horizontal selection section 133 while scanning each horizontal selection switch in the horizontal selection section 133. As a result of the selection scanning by the column scanning section 134, the signal of each pixel transmitted via each vertical signal line Lsig is sequentially output to the horizontal signal line 135, and transmitted to the outside of the semiconductor substrate 11 through the horizontal signal line 135.

[0157] The circuit section composed of the row scanning section 131, the horizontal selection section 133, the column scanning section 134 and the horizontal signal line 135 may be directly formed on the semiconductor substrate 11, or may be arranged in an external control IC. Alternatively, the circuit section may be formed on another substrate connected using a cable or the like.

[0158] The system control section 132 receives a clock supplied from the outside of the semiconductor substrate 11, data indicating an operation mode, and the like. The system control section 132 also outputs data such as internal information of the imaging element 1. The system control section 132 further includes a timing generator that generates various timing signals, and performs drive control of peripheral circuits (such as the row scanning section 131, the horizontal selection section 133, and the column scanning section 134) based on the various timing signals generated by the timing generator.

[0159] (Application Example 2)

[0160] The above-described imaging element 1 is applicable to any type of electronic equipment having an imaging function, for example, a camera system such as a digital still camera and a video camera, and a mobile phone having an imaging function. Fig.21 The general structure of a camera 2 as an example is shown. The camera 2 is, for example, a video camera capable of capturing still images or capturing moving images. The camera 2 includes, for example, an imaging element 1, an optical system (optical lens) 310, a shutter device 311, a driving section 313 that drives the imaging element 1 and the shutter device 311, and a signal processing section 312.

[0161] The optical system 310 guides the image light (incident light) from the subject to the pixel portion 1a of the imaging element 1. The optical system 310 may be composed of a plurality of optical lenses. The shutter device 311 controls the illumination period and the light shielding period for the imaging element 1. The driving section 313 controls the transmission operation of the imaging element 1 and the shutter operation of the shutter device 311. The signal processing section 312 performs various types of signal processing on the signal output from the imaging element 1. The image signal Dout after the signal processing is stored in a storage medium such as a memory or is output to a monitor or the like.

[0162] (Application Example 3)

[0163] <Examples of practical applications of in vivo information acquisition systems>

[0164] In addition, the technology according to the embodiment of the present invention (the present technology) is applicable to various products. For example, the technology according to the embodiment of the present invention can be applied to an endoscopic surgery system.

[0165] Fig. 22 : is a block diagram showing an example of a schematic configuration of an in-vivo information collection system of a patient using a capsule endoscope to which a technology according to an embodiment of the present invention (the present technology) can be applied.

[0166] The in-vivo information acquisition system 10001 includes a capsule endoscope 10100 and an external control device 10200 .

[0167] During the examination, the patient swallows the capsule endoscope 10100. The capsule endoscope 10100 has an imaging function and a wireless communication function, and it continuously captures images of the inside of an organ such as the stomach or intestine (hereinafter referred to as in-vivo images) at predetermined time intervals as it moves inside the organ by peristalsis for a period of time until it is naturally expelled by the patient. Then, the capsule endoscope 10100 successfully transmits the information of the in-vivo images to the external control device 10200 outside the body through wireless transmission.

[0168] The external control device 10200 integrally controls the operation of the in-vivo information acquisition system 10001. In addition, the external control device 10200 receives in-vivo image information transmitted thereto from the capsule endoscope 10100 and generates image data for displaying the in-vivo image on a display device (not shown) based on the received in-vivo image information.

[0169] In the in-vivo information acquisition system 10001, in-vivo images of the patient's internal state can be acquired at any time in this manner during the period from when the capsule endoscope 10100 is swallowed to when it is excreted.

[0170] The structure and function of the capsule endoscope 10100 and the external control device 10200 will be described in detail below.

[0171] The capsule endoscope 10100 includes a capsule-shaped shell 10101, which contains a light source unit 10111, a camera unit 10112, an image processing unit 10113, a wireless communication unit 10114, a power supply unit 10115, a power supply unit 10116 and a control unit 10117.

[0172] The light source unit 10111 includes, for example, a light source such as a light emitting diode (LED), and irradiates light onto the imaging field of the imaging unit 10112 .

[0173] The imaging unit 10112 includes an imaging unit and an optical system. The optical system includes a plurality of lenses disposed in a stage preceding the imaging element. Reflected light (hereinafter referred to as observation light) of light irradiated on body tissue as an observation target is gathered by the optical system and introduced into the imaging element. In the imaging unit 10112, the incident observation light is photoelectrically converted by the imaging element, thereby generating an image signal corresponding to the observation light. The image signal generated by the imaging unit 10112 is provided to the image processing unit 10113.

[0174] The image processing unit 10113 includes a processor such as a central processing unit (CPU) or a graphics processing unit (GPU), and performs various image processing on the image signal generated by the imaging unit 10112. The image processing unit 10113 provides the image signal on which the signal processing has been performed to the wireless communication unit 10114 as RAW data.

[0175] The wireless communication unit 10114 performs predetermined processing such as modulation processing on the image signal that has been signal-processed by the image processing unit 10113, and transmits the processed image signal to the external control device 10200 through the antenna 10114A. In addition, the wireless communication unit 10114 receives a control signal related to the drive control of the capsule endoscope 10100 from the external control device 10200 through the antenna 10114A. The wireless communication unit 10114 provides the control signal received from the external control device 10200 to the control unit 10117.

[0176] The power supply unit 10115 includes an antenna coil for receiving power, a power regeneration circuit for regenerating power from a current generated by the antenna coil, a boost circuit, etc. The power supply unit 10115 generates power using a non-contact charging principle.

[0177] The power supply unit 10116 includes a storage battery, and stores the power generated by the power supply unit 10115. Fig.10In order to avoid complicated illustration, arrows indicating the power supply destination from the power supply unit 10116 are omitted. However, the power stored in the power supply unit 10116 is provided to and can be used to drive the light source unit 10111, the camera unit 10112, the image processing unit 10113, the wireless communication unit 10114 and the control unit 10117.

[0178] The control unit 10117 includes a processor such as a CPU, and appropriately controls the driving of the light source unit 10111, the camera unit 10112, the image processing unit 10113, the wireless communication unit 10114 and the power supply unit 10115 according to a control signal transmitted thereto from the external control device 10200.

[0179] The external control device 10200 includes a processor such as a CPU or a GPU, a microcomputer, or a control board in which a processor and a storage element such as a memory are mixedly integrated, etc. The external control device 10200 sends a control signal to the control unit 10117 of the capsule endoscope 10100 through the antenna 10200A to control the operation of the capsule endoscope 10100. In the capsule endoscope 10100, for example, the irradiation condition of the light on the observation target of the light source unit 10111 can be changed according to the control signal from the external control device 10200. In addition, the conditions for image shooting (for example, the frame rate, the exposure value, etc. of the camera unit 10112) can be changed according to the control signal from the external control device 10200. In addition, the content processed by the image processing unit 10113 or the conditions for transmitting the signal from the wireless communication unit 114 (for example, the transmission interval, the number of transmitted images, etc.) can be changed according to the control signal from the external control device 10200.

[0180] In addition, the external control device 10200 performs various image processing on the image signal transmitted to it from the capsule endoscope 10100 to generate image data for displaying the captured in-vivo image on the display device. As image processing, various signal processing such as development processing (demosaic processing), image quality improvement processing (bandwidth enhancement processing, super-resolution processing, noise reduction (NR) processing and / or image stabilization processing) and / or magnification processing (electronic zoom processing) can be performed, for example. The external control device 10200 controls the driving of the display device so that the display device displays the captured in-vivo image based on the generated image data. Alternatively, the external control device 10200 can also control a recording device (not shown) to record the generated image data, or control a printing device (not shown) to output the generated image data by printing.

[0181] An example of an in-vivo information acquisition system to which the technology of an embodiment of the present invention is applied is described above. The technology according to an embodiment of the present invention is applied to the imaging unit 10112 in the above-described configuration, for example. This makes it possible to improve the accuracy of detection.

[0182] (Application Example 4)

[0183] <Examples of practical applications of endoscopic surgery systems>

[0184] The technology according to the embodiment of the present invention (the present technology) can be applied to various products. For example, the technology according to the embodiment of the present invention can be applied to an endoscopic surgery system.

[0185] Fig.23 : is a view showing an example of a schematic configuration of an endoscopic surgery system to which the technology according to the embodiment of the present invention (the present technology) can be applied.

[0186] exist Fig.23 , a state is shown in which a surgeon (doctor) 11131 is using an endoscopic surgery system 11000 to perform surgery on a patient 11132 on a bed 11133. As shown in the figure, the endoscopic surgery system 11000 includes an endoscope 11100, other surgical tools 11110 (e.g., a pneumoperitoneum tube 11111 and an energy device 11112), a support arm device 11120 (supporting the endoscope 11100 thereon), and a cart 11200, on which various devices used for endoscopic surgery are loaded.

[0187] The endoscope 11100 includes a lens barrel 11101 and a camera 11102 connected to the proximal end of the lens barrel 11101, and the lens barrel 11101 has a region of a predetermined length from its distal end for insertion into a body cavity of a patient 11132. In the illustrated example, the endoscope 11100 is illustrated as a rigid endoscope including the lens barrel 11101 as having a hard type. However, the endoscope 11100 may also be a flexible endoscope including the lens barrel 11101 as having flexibility.

[0188] The lens barrel 11101 has an opening at its distal end for mounting an objective lens. The light source device 11203 is connected to the endoscope 11100 so that the light generated by the light source device 11203 is guided to the distal end of the lens barrel 11101 through a light guide extending inside the lens barrel 11101, and irradiates the observation target in the body cavity of the patient 11132 through the objective lens. It should be noted that the endoscope 11100 may be a forward-looking endoscope, or may be an oblique-looking endoscope or a side-looking endoscope.

[0189] An optical system and an imaging element are provided inside the camera head 11102, so that the reflected light (observation light) from the observation target is gathered on the imaging element by the optical system. The imaging element performs photoelectric conversion on the observation light to generate an electrical signal corresponding to the observation light, that is, an image signal corresponding to the observation image. The image signal is sent to the camera control unit (CCU) 11201 as raw data (RAW data).

[0190] The CCU 11201 includes a central processing unit (CPU), a graphics processing unit (GPU), etc., and centrally controls the operations of the endoscope 11100 and the display device 11202. In addition, the CCU 11201 receives an image signal from the camera 11102, and performs various image processing such as development processing (demosaic processing) on ​​the image signal for displaying an image based on the image signal.

[0191] The display device 11202 displays an image based on an image signal on which image processing has been performed by the CCU 11201 under the control of the CCU 11201 .

[0192] The light source device 11203 includes a light source such as, for example, a light emitting diode (LED), and provides illumination light to the endoscope 11100 when imaging the surgical field.

[0193] The input device 11204 is an input interface for the endoscopic surgery system 11000. The user can perform input of various types of information or instructions to the endoscopic surgery system 11000 through the input device 11204. For example, the user can change image capturing conditions (type of irradiation light, magnification or focal length, etc.) by inputting instructions or the like through the endoscope 11100.

[0194] The treatment tool control device 11205 controls the driving of the energy device 11112 for cauterizing or cutting tissue, sealing blood vessels, etc. The pneumoperitoneum device 11206 delivers gas into the body cavity of the patient 11132 through the pneumoperitoneum tube 11111 to inflate the body cavity to ensure the field of view of the endoscope 11100 and to ensure the working space of the surgeon. The recorder 11207 is a device capable of recording various types of information related to the operation. The printer 11208 is a device capable of printing various types of information related to the operation in various forms (such as text, images, or graphics).

[0195] It should be noted that the light source device 11203 that provides the irradiation light when the surgical area is imaged to the endoscope 11100 may include a white light source such as an LED, a laser light source, or a combination thereof. In the case where the white light source includes a combination of red, green, and blue (RGB) laser light sources, since the output intensity and output timing of each color (each wavelength) can be controlled with high precision, the light source device 11203 can perform white balance adjustment of the captured image. In addition, in this case, if the laser beams from each RGB laser light source are irradiated onto the observation target in a time-sharing manner, and the drive of the image capturing device of the camera 11102 is controlled synchronously with the irradiation timing, it is also possible to capture images corresponding to each of R, G, and B in a time-sharing manner. According to this method, a color image can be obtained even if a color filter is not provided for the image capturing device.

[0196] In addition, the light source device 11203 can be controlled so that the intensity of the light to be output changes at each predetermined time. By controlling the drive of the camera device of the camera 11102 in synchronization with the timing of the change in light intensity to acquire images in a time-sharing manner and synthesize these images, it is possible to create an image with a high dynamic range without underexposed shadows and overexposed highlights.

[0197] In addition, the light source device 11203 can be configured to provide light of a predetermined wavelength band that can be used for special light observation. In special light observation, for example, by utilizing the wavelength dependence of light absorption in human tissue to irradiate light of a narrower wavelength band than the irradiation light (i.e., white light) for ordinary observation, narrow-band light observation for imaging predetermined tissues (e.g., blood vessels on the surface of mucous membranes, etc.) with high contrast is performed. Alternatively, in special light observation, fluorescence observation for obtaining images by fluorescence generated by irradiation with excitation light can be performed. In fluorescence observation, fluorescence from body tissue can be observed by irradiating excitation light onto body tissue (autofluorescence observation) or a fluorescent image can be obtained by locally injecting an agent (such as indocyanine green (ICG)) and irradiating excitation light corresponding to the fluorescence wavelength of the agent onto human tissue. The light source device 11203 can be configured to provide narrow-band light and / or excitation light suitable for the above-mentioned special light observation.

[0198] Fig.24 It shows Fig.23 A block diagram of an example of the functional configuration of the camera 11102 and CCU 11201 illustrated in FIG.

[0199] The camera 11102 includes a lens unit 11401, an imaging unit 11402, a driving unit 11403, a communication unit 11404, and a camera control unit 11405. The CCU 11201 includes a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera 11102 and the CCU 11201 are connected to each other through a transmission cable 11400 for communication.

[0200] The lens unit 11401 is an optical system provided at a connection position with the lens barrel 11101. Observation light taken from the distal end of the lens barrel 11101 is guided to the camera head 11102 and introduced into the lens unit 11401. The lens unit 11401 includes a combination of a plurality of lenses including a zoom lens and a focus lens.

[0201] The number of imaging devices included in the imaging unit 11402 can be one (single-board type) or multiple (multi-board type). For example, in the case where the imaging unit 11402 is configured as a multi-board type imaging unit, image signals corresponding to each of R, G and B are generated by the imaging element, and the above-mentioned image signals can be synthesized to obtain a color image. The imaging unit 11402 can also be constructed to have a pair of imaging elements for respectively acquiring image signals for the right eye and for the left eye, thereby being used for three-dimensional (3D) display. If 3D display is performed, the surgeon 11131 can more accurately understand the depth of living tissue in the surgical area. It should be noted that in the case where the imaging unit 11402 is configured as a stereoscopic imaging unit, a plurality of systems of lens units 11401 corresponding to the respective imaging elements are provided.

[0202] In addition, the imaging unit 11402 does not have to be arranged on the camera head 11102. For example, the imaging unit 11402 can be arranged inside the lens barrel 11101, immediately behind the objective lens.

[0203] The driving unit 11403 includes an actuator and moves the zoom lens and the focus lens of the lens unit 11401 by a predetermined distance along the optical axis under the control of the camera control unit 11405. Therefore, the magnification and focus of the image captured by the camera unit 11402 can be appropriately adjusted.

[0204] The communication unit 11404 includes a communication device for transmitting and receiving various types of information to and from the CCU 11201. The communication unit 11404 transmits an image signal acquired from the imaging unit 11402 to the CCU 11201 as RAW data via the transmission cable 11400.

[0205] In addition, the communication unit 11404 receives a control signal for controlling the driving of the camera 11102 from the CCU 11201, and provides the control signal to the camera control unit 11405. The control information includes, for example, information related to imaging conditions, such as information specifying a frame rate for capturing an image, information specifying an exposure value when capturing an image, and / or information specifying a magnification and a focus for capturing an image.

[0206] It should be noted that image capturing conditions such as frame rate, exposure value, magnification, or focus may be specified by a user or may be automatically set based on an acquired image signal by the control unit 11413 of the CCU 11201. In the latter case, the endoscope 11100 includes an automatic exposure (AE) function, an automatic focus (AF) function, and an automatic white balance (AWB) function.

[0207] The camera control unit 11405 controls the driving of the camera 11102 based on the control signal received from the CCU 11201 through the communication unit 11404 .

[0208] The communication unit 11411 includes a communication device for sending various types of information to the camera 11102 and receiving various types of information from the camera 11102. Through the transmission cable 11400, the communication unit 11411 receives an image signal sent thereto from the camera 11102.

[0209] In addition, the communication unit 11411 sends a control signal for controlling the driving of the camera 11102 to the camera 11102. The image signal and the control signal can be transmitted through electrical communication, optical communication, etc.

[0210] The image processing unit 11412 performs various image processing on the image signal in the form of RAW data sent thereto from the camera 11102 .

[0211] The control unit 11413 performs various types of control related to image capturing of the operation area, etc. by the endoscope 11100 and display of captured images obtained by image capturing of the operation area, etc. For example, the control unit 11413 creates a control signal for controlling the driving of the camera head 11102 .

[0212] In addition, the control unit 11413 controls the display device 11202 to display a captured image of the surgical area, etc., based on the image signal that has been image-processed by the image processing unit 11412. Therefore, the control unit 11413 can use various image recognition technologies to recognize various objects in the captured image. For example, the control unit 11413 can recognize surgical tools such as forceps, specific living areas, bleeding, fog when the energy device 11112 is used, etc. by detecting the shape, color, etc. of the edge of the object contained in the captured image. When the control unit 11413 controls the display device 11202 to display the captured image, the control unit 11413 can use the recognition result to display various types of surgical support information in a manner overlapping with the image of the surgical area. When the surgical support information is displayed in an overlapping manner and presented to the surgeon 11131, the burden of the surgeon 11131 can be reduced, and the surgeon 11131 can confidently perform the operation.

[0213] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 to each other is an electric signal cable capable of being used for electric signal communication, an optical fiber capable of being used for optical communication, or a composite cable capable of being used for electric communication and optical communication.

[0214] Here, although in the illustrated example, communication is performed by wired communication using the transmission cable 11400, communication between the camera 11102 and the CCU 11201 may be performed by wireless communication.

[0215] An example of an endoscopic surgery system to which the technology of an embodiment of the present invention can be applied has been described above. For example, the technology according to an embodiment of the present invention can be applied to the camera unit 11402 of the above configuration. Applying the technology according to an embodiment of the present invention to the camera unit 11402 enables the detection accuracy to be improved.

[0216] It should be noted that although an endoscopic surgery system has been described here as an example, the technology according to the embodiment of the present invention can also be applied to, for example, a microsurgery system or the like.

[0217] (Application Example 5)

[0218] <Examples of practical applications on mobile objects>

[0219] The technology according to the embodiments of the present invention (the present technology) can be applied to various products. For example, the technology according to the embodiments of the present invention can be implemented in the form of a device installed on any type of mobile body. Non-limiting examples of mobile bodies may include, for example, automobiles, electric vehicles, hybrid vehicles, motorcycles, bicycles, personal mobile devices, airplanes, unmanned aerial vehicles (UAVs), ships, robots, construction machinery, and agricultural machinery (tractors).

[0220] Fig.25 : is a block diagram showing an example of a schematic configuration of a vehicle control system as an example of a moving body control system to which the technology according to the embodiment of the present invention can be applied.

[0221] The vehicle control system 12000 includes a plurality of electronic control units connected to each other via a communication network 12001. Fig.25 In the example shown, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. In addition, a microcomputer 12051, a sound and image output unit 12052, and an in-vehicle network interface (I / F) 12053 are shown as functional configurations of the integrated control unit 12050.

[0222] The drive system control unit 12010 controls the operation of devices related to the drive system of the vehicle according to various types of programs. For example, the drive system control unit 12010 is used as a control device for the following devices: a drive force generating device such as an internal combustion engine, a drive motor, etc. for generating a drive force for the vehicle, a drive force transmitting mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, a braking device for generating a braking force for the vehicle, etc.

[0223] The body system control unit 12020 controls the operation of various types of devices provided on the vehicle body according to various types of programs. For example, the body system control unit 12020 is used as a control device for a keyless entry system, a smart key system, a power window device, or various lights such as headlights, reverse lights, brake lights, turn signals, fog lights, etc. In this case, radio waves transmitted from a mobile device that replaces the key or signals of various switches may be input to the body system control unit 12020. The body system control unit 12020 receives input of these radio waves or signals and controls the door lock device, power window device, or lights of the vehicle, etc.

[0224] The vehicle exterior information detection unit 12030 detects information about the exterior of the vehicle including the vehicle control system 12000. For example, the vehicle exterior information detection unit 12030 is connected to the imaging unit 12031. The vehicle exterior information detection unit 12030 causes the imaging unit 12031 to image the image of the exterior of the vehicle and receives the imaged image. Based on the received image, the vehicle exterior information detection unit 12030 can perform a process of detecting objects such as people, vehicles, obstacles, signs, characters on the road surface, or a process of detecting the distance to the above-mentioned objects.

[0225] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 may output the electrical signal as an image, or may output the electrical signal as information about the measured distance. In addition, the light received by the imaging unit 12031 may be visible light, or may be invisible light such as infrared rays.

[0226] The in-vehicle information detection unit 12040 detects information about the interior of the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver state detection unit 12041 that detects the driver's state. The driver state detection unit 12041 includes, for example, a camera that photographs the driver. Based on the detection information input from the driver state detection unit 12041, the in-vehicle information detection unit 12040 can calculate the driver's fatigue level or the driver's concentration level, or can determine whether the driver is dozing off.

[0227] The microcomputer 12051 can calculate the control target value of the driving force generating device, the steering mechanism or the braking device based on the information about the inside or outside of the vehicle acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, and output the control command to the driving system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of the advanced driver assistance system (ADAS), and the functions of the ADAS include collision avoidance or impact mitigation of the vehicle, following driving based on the following distance, speed maintenance driving, vehicle collision warning, vehicle lane departure warning, etc.

[0228] In addition, based on the information about the exterior or interior of the vehicle acquired by the exterior information detection unit 12030 or the interior information detection unit 12040, the microcomputer 12051 can perform cooperative control aimed at realizing automatic driving, etc. by controlling the driving force generation device, the steering mechanism, the braking device, etc. The automatic driving enables the vehicle to travel autonomously without relying on the operation of the driver.

[0229] Furthermore, based on the information about the outside of the vehicle acquired by the vehicle exterior information detection unit 12030, the microcomputer 12051 may output a control command to the body system control unit 12020. For example, the microcomputer 12051 may perform cooperative control aimed at preventing glare by controlling the headlights to change from high beam to low beam, for example, according to the position of a preceding vehicle or an oncoming vehicle detected by the vehicle exterior information detection unit 12030.

[0230] The audio and video output unit 12052 sends an output signal of at least one of audio and video to an output device that can visually or auditorily notify the vehicle passengers or the outside of the vehicle. Fig.25 In the example of FIG. 1 , an audio speaker 12061, a display portion 12062, and an instrument panel 12063 are shown as output devices. The display portion 12062 may include, for example, at least one of an in-vehicle display and a head-up display.

[0231] Fig.26 It is a schematic diagram illustrating an example of the installation position of the imaging unit 12031.

[0232] exist Fig.26 In the figure, the imaging unit 12031 includes an imaging unit 12101, an imaging unit 12102, an imaging unit 12103, an imaging unit 12104 and an imaging unit 12105.

[0233] The imaging unit 12101, the imaging unit 12102, the imaging unit 12103, the imaging unit 12104 and the imaging unit 12105 are, for example, arranged at various positions on the front nose, the side mirrors, the rear bumper and the rear door of the vehicle 12100 and at the position on the upper part of the windshield in the vehicle. The imaging unit 12101 arranged at the front nose and the imaging unit 12105 arranged at the upper part of the windshield in the vehicle mainly acquire images in front of the vehicle 12100. The imaging unit 12102 and the imaging unit 12103 arranged at the side mirrors mainly acquire images on both sides of the vehicle 12100. The imaging unit 12104 arranged on the rear bumper or the rear door mainly acquires images at the rear of the vehicle 12100. The imaging unit 12105 arranged at the upper part of the windshield in the vehicle is mainly used to detect vehicles in front, pedestrians, obstacles, signals, traffic signs, lanes, etc.

[0234] By the way, Fig.26An example of the imaging range of the imaging unit 12101 to the imaging unit 12104 is shown. The imaging range 12111 represents the imaging range of the imaging unit 12101 provided at the front nose. The imaging ranges 12112 and 12113 respectively represent the imaging ranges of the imaging unit 12102 and the imaging unit 12103 provided at the side mirror. The imaging range 12114 represents the imaging range of the imaging unit 12104 provided on the rear bumper or the rear cover. For example, a bird's-eye view image of the vehicle 12100 observed from above is obtained by superimposing the image data imaged by the imaging units 12101 to the imaging units 12104.

[0235] At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera composed of a plurality of imaging elements, or may be an imaging element having pixels for phase difference detection.

[0236] For example, based on the distance information acquired from the imaging unit 12101 to the imaging unit 12104, the microcomputer can determine the distance of each three-dimensional object within the imaging range 12111 to the imaging range 12114 and the time change of the distance (relative speed relative to the vehicle 12100), and thereby extract the closest three-dimensional object that is particularly on the driving path of the vehicle 12100 and travels in the same direction as the vehicle 12100 at a predetermined speed (e.g., equal to or greater than 0 km / h) as the leading vehicle. In addition, the microcomputer 12051 can pre-set the following distance to be maintained in front of the leading vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. Therefore, it is possible to perform cooperative control such as automatic driving that aims to make the vehicle travel autonomously without relying on the driver's operation.

[0237] For example, based on the distance information obtained from the imaging unit 12101 to the imaging unit 12104, the microcomputer 12501 can classify the three-dimensional object data about the three-dimensional object into three-dimensional object data of two-wheeled vehicles, standard vehicles, large vehicles, pedestrians, electric poles and other three-dimensional objects, extract the classified three-dimensional object data, and use the extracted three-dimensional object data for automatic avoidance of obstacles. For example, the microcomputer 12051 classifies the obstacles around the vehicle 12100 into obstacles that the driver of the vehicle 12100 can visually identify and obstacles that the driver of the vehicle 12100 is difficult to visually identify. Then, the microcomputer 12051 determines the collision risk for indicating the risk of collision with each obstacle. When the collision risk is equal to or higher than the set value and therefore there is a possibility of collision, the microcomputer 12051 issues a warning to the driver via the audio speaker 12061 or the display unit 12062, and performs forced deceleration or evasive steering through the drive system control unit 12010. Therefore, the microcomputer 12051 can assist driving to avoid collisions.

[0238] At least one imaging unit of the imaging units 12101 to 12104 may be an infrared camera that detects infrared rays. The microcomputer 12051 may identify pedestrians, for example, by determining whether there are pedestrians in the images imaged by the imaging units 12101 to 12104. For example, such identification of pedestrians is performed by the following steps: a step of extracting feature points in the imaged images of the imaging units 12101 to 12104 as infrared cameras; and a step of performing pattern matching processing on a series of feature points representing the contours of the object to determine whether it is a pedestrian. If the microcomputer 12051 determines that there are pedestrians in the imaged images of the imaging units 12101 to 12104, and thus identifies the pedestrians, the sound and image output unit 12052 will control the display unit 12062 to display the square contour line for emphasis as superimposed on the identified pedestrian. In addition, the sound and image output unit 12052 may also control the display unit 12062 so as to display an icon representing a pedestrian, etc., at a desired position.

[0239] The description has been given above with reference to the embodiment and the modified example and the application example, however, the content of the present invention is not limited to the above embodiment and the like, and various modifications can be made. For example, in the above embodiment, the imaging element has a structure in which four inorganic photoelectric conversion sections 11B and four inorganic photoelectric conversion sections 11R for detecting blue light and red light are stacked in sequence with respect to one organic photoelectric section 11G for detecting green light. However, the content of the present invention is not limited to this structure.

[0240] For example, a structure may be adopted in which eight inorganic photoelectric converters (eight pixels) 11B and eight inorganic photoelectric converters (eight pixels) 11R that detect blue light and red light are stacked in sequence, respectively, relative to one organic photoelectric converter 11G that detects green light. In addition, a structure may be adopted in which two organic photoelectric converters and one inorganic photoelectric converter are stacked. In this case, two organic photoelectric converters may be formed with the same pixel pitch; or, however, as with the inorganic photoelectric converters 11B and 11R described above, the organic photoelectric converter disposed on the inorganic photoelectric converter side may be formed to have a narrower pixel pitch than the organic photoelectric converter disposed on the light incident side.

[0241] In addition, the above-mentioned embodiments and the like illustrate the structure of the back-illuminated imaging element; however, the contents of the present invention are also applicable to the front-illuminated imaging element. In addition, the imaging element of the present invention does not need to include all the components described in the above-mentioned embodiments, and may include any other layers instead.

[0242] It should be noted that the effects described herein are merely exemplary and not limiting, and other effects may also be included.

[0243] It should be noted that the present invention may have the following configurations: (1)

[0245] An imaging element, comprising:

[0246] a first photoelectric conversion section; and

[0247] A second photoelectric conversion unit, wherein the first photoelectric conversion unit and the second photoelectric conversion unit are stacked in order from the light incident side, and selectively detect light beams of different wavelength bands and perform photoelectric conversion;

[0248] The second photoelectric conversion portions are arranged at intervals narrower than a pixel pitch of the first photoelectric conversion portions. (2)

[0250] The imaging element according to (1), wherein four pixels of the second photoelectric conversion portion are arranged with respect to one pixel of the first photoelectric conversion portion. (3)

[0252] The imaging element according to (1), wherein eight pixels of the second photoelectric conversion portion are arranged with respect to one pixel of the first photoelectric conversion portion. (4)

[0254] The imaging element according to any one of (1) to (3), wherein

[0255] The first photoelectric conversion unit includes an organic photoelectric conversion unit formed using an organic material, and

[0256] The second photoelectric conversion region includes an inorganic photoelectric conversion region formed to be embedded in a semiconductor substrate. (5)

[0258] The imaging element according to (4), further comprising a third photoelectric conversion unit that selectively detects light of a wavelength band different from that of the first photoelectric conversion unit and the second photoelectric conversion unit and performs photoelectric conversion, the third photoelectric conversion unit being disposed between the first photoelectric conversion unit and the second photoelectric conversion unit, wherein

[0259] The third photoelectric conversion region includes an inorganic photoelectric conversion region formed to be embedded in the semiconductor substrate. (6)

[0261] The imaging element according to (5), wherein the third photoelectric conversion portions are arranged at intervals narrower than the pixel pitch of the first photoelectric conversion portions. (7)

[0263] The imaging element according to (5) or (6), wherein four pixels of the third photoelectric conversion section are arranged with respect to one pixel of the first photoelectric conversion section. (8)

[0265] The imaging element according to (5) or (6), wherein eight pixels of the third photoelectric conversion portion are arranged with respect to one pixel of the first photoelectric conversion portion. (9)

[0267] The imaging element according to any one of (5) to (8), wherein

[0268] The first photoelectric conversion section performs photoelectric conversion of green light, and

[0269] The second photoelectric conversion portion and the third photoelectric conversion portion perform photoelectric conversion of red light or blue light, respectively. (10)

[0271] The imaging element according to (4), further comprising a third photoelectric conversion unit that selectively detects light of a wavelength band different from that of the first photoelectric conversion unit and the second photoelectric conversion unit and performs photoelectric conversion, the third photoelectric conversion unit being disposed between the first photoelectric conversion unit and the second photoelectric conversion unit, wherein

[0272] The third photoelectric conversion portion includes an organic photoelectric conversion portion formed on the semiconductor substrate. (11)

[0274] The imaging element according to (10), wherein the third photoelectric conversion portion is arranged at the same pixel pitch as the first photoelectric conversion portion. (12)

[0276] An electronic device comprising an imaging element,

[0277] The imaging element comprises:

[0278] a first photoelectric conversion section, and

[0279] A second photoelectric conversion unit, wherein the first photoelectric conversion unit and the second photoelectric conversion unit are stacked in order from the light incident side, and selectively detect light beams of different wavelength bands and perform photoelectric conversion;

[0280] The second photoelectric conversion portions are arranged at intervals narrower than a pixel pitch of the first photoelectric conversion portions. (13)

[0282] A method for driving an imaging element, the imaging element comprising a first electrode portion and a second electrode portion stacked in sequence from a light incident side and selectively detecting light beams of different wavelength bands and performing photoelectric conversion, the second photoelectric conversion portion being arranged at intervals narrower than a pixel pitch of the first photoelectric conversion portion, the method comprising:

[0283] acquiring a color signal of the first light using one pixel of the first photoelectric conversion unit, and

[0284] A color signal of second light having a wavelength band different from that of the first light is acquired by adding the second photoelectric conversion sections. (14)

[0286] The method for driving an imaging element according to (13), wherein:

[0287] The imaging element has a high-resolution mode, a high-sensitivity mode, and a high-speed mode as operation modes, and,

[0288] In the high-resolution mode and the high-speed mode, acquisition of the color signal of the second light is performed by adding four (2×2) pixels of the second photoelectric conversion portion with respect to one pixel of the first photoelectric conversion portion. (15)

[0290] The method for driving an imaging element according to (13), wherein:

[0291] The imaging element has a high-resolution mode, a high-sensitivity mode, and a high-speed mode as operation modes, and,

[0292] In the high-sensitivity mode, acquisition of the color signal of the second light is performed by adding sixteen (4×4) pixels of the second photoelectric conversion portion with respect to one pixel of the first photoelectric conversion portion.

[0293] This application claims priority from Japanese Patent Application JP2018-096530 filed with the Japan Patent Office on May 18, 2018, the entire contents of which are hereby incorporated by reference.

[0294] Those skilled in the art should understand that various modifications, combinations, sub-combinations and changes may be made within the scope of the appended claims or the equivalents of the claims according to design requirements and other factors.

Claims

1. A light detection device, comprising: a first photoelectric conversion portion configured to detect light within a first light wavelength range; and a second photoelectric conversion portion configured to detect light in a second light wavelength range, wherein the first light wavelength range is different from the second light wavelength range, wherein, in the first mode, the light detection device is configured to read a signal of a first addition mode in which a plurality of pixels of the second photoelectric conversion unit are added together and a signal of a first pixel of the first photoelectric conversion unit, wherein, in the second mode, the light detection device is configured to read a signal of a second addition mode in which a plurality of pixels of the second photoelectric conversion unit are added together, and a signal of a first pixel of the first photoelectric conversion unit; the first addition mode is different from the second addition mode, The first photoelectric conversion section and the second photoelectric conversion section are stacked, and The size of a pixel in the second photoelectric conversion portion is smaller than the size of the first pixel in the first photoelectric conversion portion.

2. The light detection device according to claim 1, wherein: Four pixels of the second photoelectric conversion portion are arranged opposite to the first pixel of the first photoelectric conversion portion.

3. The light detection device according to claim 1, wherein: Eight pixels of the second photoelectric conversion portion are arranged opposite to the first pixel of the first photoelectric conversion portion.

4. The light detection device according to any one of claims 1 to 3, wherein: In the first mode, the first addition mode adds at least three pixels among the plurality of pixels in the second photoelectric conversion portion.

5. The light detection device according to any one of claims 1 to 3, wherein: More pixels are added in the second addition mode than in the first addition mode.

6. The light detection device according to any one of claims 1 to 3, wherein: The first mode is a high resolution mode.

7. The light detection device according to any one of claims 1 to 3, wherein: The second mode is a high sensitivity mode.

8. The light detection device according to any one of claims 1 to 3, wherein: The first photoelectric conversion unit includes an organic photoelectric conversion unit formed using an organic material, and The second photoelectric conversion region includes an inorganic photoelectric conversion region formed to be embedded in a semiconductor substrate.

9. The light detection device according to claim 1, further comprising a third photoelectric conversion portion configured to detect light in a third light wavelength range, the third light wavelength range being different from the first light wavelength range and the second light wavelength range, wherein The third photoelectric conversion region includes an inorganic photoelectric conversion region formed to be embedded in a semiconductor substrate.

10. The light detection device according to claim 9, wherein: The size of a pixel in the third photoelectric conversion portion is smaller than the size of the first pixel in the first photoelectric conversion portion.

11. The light detection device according to claim 9, wherein: Four pixels of the third photoelectric conversion unit are arranged opposite to the first pixel of the first photoelectric conversion unit.

12. The light detection device according to claim 9, wherein: Eight pixels of the third photoelectric conversion portion are arranged opposite to the first pixel of the first photoelectric conversion portion.

13. The light detection device according to claim 9, wherein: The first photoelectric conversion section performs photoelectric conversion of green light, and The second photoelectric conversion portion and the third photoelectric conversion portion perform photoelectric conversion of blue light or red light, respectively.

14. The light detection device according to claim 9, wherein: In the second mode, the second photoelectric conversion portion and the third photoelectric conversion portion are configured to be offset from each other.

15. The light detection device according to claim 9, wherein: The size of a pixel in the third photoelectric conversion portion is the same as the size of a pixel in the second photoelectric conversion portion.

16. A light detection device, comprising: a first photoelectric conversion portion configured to detect light within a first light wavelength range; and a second photoelectric conversion portion configured to detect light in a second light wavelength range, wherein the first light wavelength range is different from the second light wavelength range, Wherein, the light detection device has at least two different reading modes, The first photoelectric conversion section and the second photoelectric conversion section are stacked, and The size of a pixel in the second photoelectric conversion portion is smaller than the size of a first pixel in the first photoelectric conversion portion.

17. The light detection device according to claim 16, wherein: The reading modes include a high-resolution mode and a high-sensitivity mode.

18. The light detection device according to claim 17, further comprising a third photoelectric conversion portion configured to detect light in a third light wavelength range, the third light wavelength range being different from the first light wavelength range and the second light wavelength range, wherein In the high-sensitivity mode, the second photoelectric conversion portion and the third photoelectric conversion portion are configured to be offset from each other.

19. An electronic device comprising a light detection device, The light detection device is the light detection device according to any one of claims 1 to 18.

20. A method for driving a light detection device, wherein the light detection device is the light detection device according to any one of claims 1 to 15, the method comprising: causing a first pixel of the first photoelectric conversion unit to detect light within a first light wavelength range; causing a plurality of pixels of the second photoelectric conversion portion to detect light in a second light wavelength range, wherein the first light wavelength range is different from the second light wavelength range; In a first mode, reading a signal of a first addition mode in which a plurality of pixels of the second photoelectric conversion unit are added together and a signal of a first pixel of the first photoelectric conversion unit; as well as In the second mode, a signal of a second addition mode in which a plurality of pixels of the second photoelectric conversion unit are added and a signal of a first pixel of the first photoelectric conversion unit are read. Wherein, the first addition mode is different from the second addition mode.

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