Semiconductor device and electronic apparatus

The present technology relates to a semiconductor device and an electronic apparatus that are capable of improving the characteristics of a semiconductor device or an electronic apparatus that includes a pixel having a metallic filter and a pixel not having the metallic filter. A semiconductor device includes: a pixel unit in which a first pixel including a metallic filter and a second pixel not including the metallic filter are disposed adjacent to each other; and a reflected light reduction unit that reduces reflected light on a sidewall of the metallic filter at a boundary portion between the first pixel and the second pixel. The present technology can be applied to an image sensor that includes a narrowband pixel including a plasmon filter and a normal pixel including a color filter, for example.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase of International Patent Application No. PCT/JP2019/000130 filed on Jan. 8, 2019, which claims priority benefit of Japanese Patent Application No. JP 2018-008111 filed in the Japan Patent Office on Jan. 22, 2018. Each of the above-referenced applications is hereby incorporated herein by reference in its entirety.

TECHNICAL FIELD

The technology according to the present disclosure (the technology will be hereinafter also referred to as the present technology) relates to a semiconductor device and an electronic apparatus, and more particularly, to a semiconductor device and an electronic apparatus that include a pixel having a metallic filter and a pixel not having the metallic filter.

BACKGROUND ART

There is a suggested imaging device in which the imaging region to be used for acquiring an image and the spectral region to be used for acquiring a color spectrum are formed in the same pixel region (see Patent Document 1, for example).

CITATION LIST

Patent Document

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

In the imaging device disclosed in Patent Document 1, color filters of a non-metallic organic material are used for the pixels in the imaging region, and plasmon filters made of a metal such as aluminum are used for the pixels in the spectral region, for example. Therefore, at a boundary portion between the imaging region and the spectral region, light reflected irregularly by a sidewall of a plasmon filter enters the imaging region, and as a result, the characteristics of the imaging device are degraded.

The present technology has been made in view of such circumstances, and is to improve the characteristics of a semiconductor device or an electronic apparatus that includes a pixel having a metallic filter and a pixel not having the metallic filter.

Solutions to Problems

A semiconductor device according to a first aspect of the present technology includes: a pixel unit in which a first pixel including a metallic filter and a second pixel not including the metallic filter are disposed adjacent to each other; and a reflected light reduction unit that reduces reflected light on a sidewall of the metallic filter at a boundary portion between the first pixel and the second pixel.

An electronic apparatus according to a second aspect of the present technology includes: a semiconductor device; and a signal processing unit that processes a signal output from the semiconductor device. In the electronic apparatus, the semiconductor device includes: a pixel unit in which a first pixel including a metallic filter and a second pixel not including the metallic filter are disposed adjacent to each other; and a reflected light reduction unit that reduces reflected light on a sidewall of the metallic filter at a boundary portion between the first pixel and the second pixel.

In the first aspect or the second aspect of the present technology, reflected light on the sidewall of the metallic filter at the boundary portion between the first pixel including the metallic filter and the second pixel not including the metallic filter is reduced.

Effects of the Invention

According to the first aspect of the present technology, it is possible to improve the characteristics of a semiconductor device that includes a pixel having a metallic filter and a pixel not having the metallic filter.

According to the second aspect of the present technology, it is possible to improve the characteristics of an electronic apparatus that includes a pixel having a metallic filter and a pixel not having the metallic filter.

Note that effects of the present technology are not limited to the effects described herein, and may include any of the effects described in the present disclosure.

MODES FOR CARRYING OUT THE INVENTION

The following is a detailed description of modes for carrying out the invention (these modes will be hereinafter referred to as “embodiments”), with reference to the accompanying drawings. Note that explanation will be made in the following order.

1. Example configuration of an imaging apparatus

2. First embodiment (an example in which a light absorber is disposed at a higher location than narrowband filters)

3. Second embodiment (an example in which a sidewall of a narrowband filter is covered with a light absorber)

4. Third embodiment (an example in which a sidewall of a narrowband filter is covered with a low-reflection film)

5. Fourth embodiment (an example in which a sidewall of a narrowband filter is inclined)

6. Example positions of a reflected light reduction unit in a pixel array

7. Fifth embodiment (an example in which an antireflective film is provided on the light incident surface of each narrowband filter)

8. Modifications of the filters of normal pixels and narrowband pixels

9. Image processing in an imaging apparatus

10. Example applications

1. Example Configuration of an Imaging Apparatus

<Example Configuration of an Imaging Apparatus10>

FIG. 1is a block diagram showing an example configuration of an imaging apparatus10that is an electronic apparatus to which the present technology is applied.

The imaging apparatus10is formed with a digital camera that is capable of capturing both still images and moving images, for example. The imaging apparatus10is capable of detecting (multispectral) light of four or more wavelength bands (at least four bands) that are more than the conventional three wavelength bands (three bands) of R (red), G (green), and B (blue), or Y (yellow), M (magenta), and C (cyan) based on the three primary colors or the color-matching functions.

The imaging apparatus10includes an optical system11, an imaging device12, a memory13, a signal processing unit14, an output unit15, and a control unit16.

The optical system11includes a zoom lens, a focus lens, a diaphragm, and the like (not shown), for example, and causes light from outside to enter the imaging device12. The optical system11also includes various kinds of filters such as a polarization filter as needed.

The imaging device12is formed with a complementary metal oxide semiconductor (CMOS) image sensor, for example. The imaging device12receives the incident light from the optical system11, performs photoelectric conversion, and outputs the image data corresponding to the incident light.

The memory13temporarily stores the image data the imaging device12has output.

The signal processing unit14performs signal processing (processing such as denoising and white balance adjustment, for example) using the image data stored in the memory13, and supplies the resultant image data to the output unit15.

The output unit15outputs the image data supplied from the signal processing unit14. For example, the output unit15includes a display (not shown) formed with liquid crystal or the like, and displays the spectrum (image) corresponding to the image data supplied from the signal processing unit14as a so-called through-lens image. The output unit15includes a driver (not shown) for driving a recording medium such as a semiconductor memory, a magnetic disk, or an optical disk, for example, and records the image data supplied from the signal processing unit14on the recording medium. For example, the output unit15functions as a communication interface that communicates with an external device (not shown), and transmits the image data from the signal processing unit14to the external device in a wireless or wired manner.

The control unit16controls the respective components of the imaging apparatus10, in accordance with a user operation or the like.

Note that image data will be hereinafter also referred to simply as an image.

<Example Circuit Configuration of the Imaging Device>

FIG. 2is a block diagram showing an example circuit configuration of the imaging device12shown inFIG. 1.

The imaging device12includes a pixel array31, a row scanning circuit32, a phase locked loop (PLL)33, a digital-analog converter (DAC)34, a column analog-digital converter (ADC) circuit35, a column scanning circuit36, and a sense amplifier37.

The pixel array31is a pixel unit in which a plurality of pixels51is two-dimensionally arranged.

Each pixel51is disposed at a point where a horizontal signal line H connected to the row scanning circuit32and a vertical signal line V connected to the column ADC circuit35intersect, and includes a photodiode61that performs photoelectric conversion, and several kinds of transistors for reading stored signals. That is, each pixel51includes a photodiode61, a transfer transistor62, a floating diffusion63, an amplification transistor64, a selection transistor65, and a reset transistor66, as shown in an enlarged view on the right side inFIG. 2.

The electric charges stored in the photodiode61are transferred to the floating diffusion63via the transfer transistor62. The floating diffusion63is connected to the gate of the amplification transistor64. When a pixel51becomes the target from which a signal is to be read out, the selection transistor65is turned on by the row scanning circuit32via the horizontal signal line H, and the amplification transistor64is driven by source follower driving, so that the signal of the selected pixel51is read out as the pixel signal corresponding to the amount of the electric charges stored in the photodiode61into the vertical signal line V. Further, the reset transistor66is turned on, to reset the pixel signal.

The row scanning circuit32sequentially outputs drive signals for driving (transferring, selecting, resetting, and the like, for example) the pixels51of the pixel array31row by row.

The PLL33generates and outputs a clock signal of a predetermined frequency required for driving the respective components of the imaging device12, on the basis of a clock signal supplied from the outside.

The DAC34generates and outputs a ramp signal having a shape (almost a sawtooth shape) that returns to a predetermined voltage value after the voltage drops at a predetermined gradient from a predetermined voltage value.

The column ADC circuit35includes comparators71and counters72that correspond in number to the columns of the pixels51of the pixel array31. The column ADC circuit35extracts signal levels from pixel signals output from the pixels51by performing a correlated double sampling (CDS) operation, and then outputs pixel data. That is, the comparators71compare the ramp signal supplied from the DAC34with the pixel signals (luminance values) output from the pixels51, and supply the resultant comparison result signals to the counters72. In accordance with the comparison result signals output from the comparators71, the counters72then count the counter clock signals of a predetermined frequency, so that the pixel signals are subjected to A/D conversion.

The column scanning circuit36supplies the counters72of the column ADC circuit35sequentially with signals for outputting the pixel data at predetermined timings.

The sense amplifier37amplifies the pixel data supplied from the column ADC circuit35, and outputs the amplified pixel data to the outside of the imaging device12.

<Example Configuration of the Imaging Device>

FIG. 3shows an example configuration of the pixel array31of the imaging device12shown inFIG. 2.

In this example, the periphery of a normal pixel region31A is surrounded by a narrowband pixel region31B.

The normal pixel region31A is used primarily for imaging an object. For example, pixels51each including a color filter that is a filter made of a non-metallic material (a non-metallic filter) are disposed in the normal pixel region31A.

Note that a color filter may be either of an organic material type or of an inorganic material type. For example, organic color filters include dyed/colored filters using a synthetic resin or a natural protein, and dye-containing filters using pigment dyestuff or coloring dyestuff. Further, a material such as TiO2, ZnS, SiN, MgF2, SiO2, or a Low-k material is used for inorganic color filters, for example. Furthermore, a technique such as vapor deposition, sputtering, or chemical vapor deposition (CVD) film formation is used to form inorganic color filters, for example.

A color filter transmission band (color) is set for each pixel51, and the types and the layout of the colors are selected as appropriate. For example, the color filters include filters of three colors: R (red), G (green), and B (blue), or Y (yellow), M (magenta), and C (cyan).

Note that color filters are not necessarily used in the normal pixel region31A. In this case, the normal pixel region31A is used for capturing monochrome images.

The narrowband pixel region31B is used primarily for measuring the spectral characteristics of the object. In the narrowband pixel region31B, for example, pixels51each including a narrowband filter that is an optical filter that transmits narrowband light in a predetermined narrow wavelength band (narrow band) are disposed. For example, a plasmon filter that is a kind of metallic filter using a thin film made of a metal such as aluminum, and uses surface plasmons is used as the narrowband filter.

The transmission band of the narrowband filter is set for each pixel51. The types (the number of bands) of the transmission band of the narrowband filter are set as appropriate, and may be four or more, for example.

Here, a narrow band is a wavelength band that is narrower than the transmission bands of conventional color filters of R (red), G (green), and B (blue), or Y (yellow), M (magenta), and C (cyan) based on the three primary colors or the color-matching functions, for example.

A reflected light reduction unit31C that reduces light reflected by the sidewalls of the narrowband filters is disposed at the boundary portion between the normal pixel region31A and the narrowband pixel region31B. The reflected light reduction unit31C will be described later in detail.

Note that, in a case where the pixels51in the normal pixel region31A are distinguished from the pixels51in the narrowband pixel region31B in the description below, the former will be referred to as the normal pixels51A, and the latter will be referred to as the narrowband pixels51B. Further, in the description below, an image obtained with the normal pixels51A in the normal pixel region31A will be referred to as a normal image, and an image obtained with the narrowband pixels51B in the narrowband pixel region31B will be referred to as a multispectral image.

FIG. 4schematically shows an example configuration of a cross-section of the imaging device12shown inFIG. 1.FIG. 4shows a cross-section of the four pixels: a normal pixel51A-1, a normal pixel51A-2, a narrowband pixel51B-1, and a narrowband pixel51B-2in the vicinity of a boundary portion B1between the normal pixel region31A and the narrowband pixel region31B (a boundary portion B1between a normal pixel51A and a narrowband pixel51B that are adjacent to each other) of the imaging device12.

Note that, in a case where there is no need to distinguish the normal pixel51A-1and the normal pixel51A-2from each other in the description below, the normal pixel51A-1and the normal pixel51A-2will be referred to simply as the normal pixels51A. In a case where there is no need to distinguish the narrowband pixel51B-1and the narrowband pixel51B-2from each other, the narrowband pixel51B-1and the narrowband pixel51B-2will be referred to simply as the narrowband pixels51B.

In each pixel51, an on-chip microlens101, an interlayer film102, a filter layer103, an interlayer film104, a photoelectric conversion element layer105, and a signal wiring layer106are stacked in this order from the top. That is, the imaging device12is a back-illuminated CMOS image sensor in which the photoelectric conversion element layer105is disposed closer to the light incident side than the signal wiring layer106.

The on-chip microlenses101are optical elements for gathering light onto the photoelectric conversion element layer105of each pixel51.

The interlayer film102and the interlayer film104include a dielectric material such as SiO2. As described later, the dielectric constant of the interlayer film102and the interlayer film104is preferably as low as possible.

In the filter layer103, color filters CF are provided for the respective normal pixel51A, and narrowband filters NB are provided for the respective narrowband pixels51B.

Note that, in the filter layer103, any color filter CF may not be provided for some or all of the normal pixels51A, for example. Also, in the filter layer103, any narrowband filter NB may not be provided for some of the narrowband pixels51B, for example.

The photoelectric conversion element layer105includes the photodiode61shown inFIG. 2(hereinafter, also referred to as the photodiode PD) and the like, for example, receives light that has passed through the filter layer103, and converts the received light into electric charges. The photoelectric conversion element layer105is also designed such that the pixels51are electrically separated from each other by a device separation layer.

The signal wiring layer106includes wiring lines and the like for reading the electric charges stored in the photoelectric conversion element layer105.

FIG. 5shows an example configuration of a plasmon filter121A having a hole array structure.

The plasmon filter121A is formed with a plasmon resonator in which holes132A are arranged in a honeycomb fashion in a metallic thin film (hereinafter, referred to as the conductive thin film)131A.

Each hole132A penetrates the conductive thin film131A, and functions as a waveguide. Generally, a waveguide has a cutoff frequency and a cutoff wavelength determined by the length of a side, the shape of the diameter, or the like, and characteristically does not allow light of frequencies equal to or lower than that (and wavelengths equal to or longer than that) to pass therethrough. The cutoff wavelength of the holes132A depends primarily on the aperture diameter D1. The smaller the aperture diameter D1, the shorter the cutoff wavelength. Note that the aperture diameter D1is set to a smaller value than the wavelength of the light to be transmitted.

On the other hand, when light enters the conductive thin film131A in which the holes132A are arranged at intervals equal to or shorter than the wavelength of the light, light having longer wavelengths than the cutoff wavelength of the holes132A passes therethrough. This phenomenon is called an abnormal plasmon transmission phenomenon. This phenomenon occurs when surface plasmons are excited at the boundary between the conductive thin film131A and the interlayer film102thereon.

Referring now toFIG. 6, the conditions for an abnormal plasmon transmission phenomenon (surface plasmon resonance) to occur are described.

FIG. 6is a graph showing the dispersion relationship of surface plasmons. In the graph, the abscissa axis indicates angular wave number vector k, and the ordinate axis indicates angular frequency ω. In the graph, ωprepresents the plasma frequency of the conductive thin film131A. Also, in the graph, ωsprepresents the surface plasma frequency at the interface between the interlayer film102and the conductive thin film131A, and is expressed by Equation (1) shown below.

In the equation, εdrepresents the dielectric constant of the dielectric material forming the interlayer film102.

According to Equation (1), the surface plasma frequency Wspbecomes higher as the plasma frequency ωpbecomes higher. The surface plasma frequency ωspalso becomes higher as the dielectric constant εdbecomes lower.

A line L1indicates the light dispersion relationship (the light line), and is expressed by Equation (2) shown below.

In the equation, c represents the speed of light.

A line L2indicates the dispersion relationship of surface plasmons, and is expressed by Equation (3) shown below.

In the equation, εmrepresents the dielectric constant of the conductive thin film131A.

The surface plasmon dispersion relationship indicated by the line L2asymptotically approaches the light line indicated by the line L1in the range in which the angular wave number vector k is small, and asymptotically approaches the surface plasma frequency ωspas the angular wave number vector k becomes greater.

When Equation (4) shown below is satisfied, an abnormal plasmon transmission phenomenon then occurs.

In the equation, λ represents the wavelength of the incident light. Further, θ represents the incident angle of the incident light. Gxand Gyare expressed by Equation (5) shown below.
|Gx|=|Gy=2π/a0(5)

In the equation, a0represents the lattice constant of the hole array structure formed with the holes132A of the conductive thin film131A.

The left-hand side of Equation (4) indicates an angular wave number vector of the surface plasmons, and the right-hand side indicates the angular wave number vector of the hole array intervals in the conductive thin film131A. Therefore, when the angular wave number vector of the surface plasmons is equal to the angular wave number vector of the hole array intervals in the conductive thin film131A, an abnormal plasmon transmission phenomenon occurs. Further, the value of A at this point of time is the plasmon resonant wavelength (the transmission wavelength of the plasmon filter121A).

Note that the angular wave number vector of the surface plasmons on the left-hand side of Equation (4) is determined by the dielectric constant εmof the conductive thin film131A and the dielectric constant εdof the interlayer film102. Meanwhile, the angular wave number vector of the hole array intervals on the right-hand side is determined by the incident angle θ of light and the pitch (hole pitch) P1between adjacent holes132A of the conductive thin film131A. Accordingly, the resonant wavelength and the resonant frequency of the plasmons are determined by the dielectric constant εmof the conductive thin film131A, the dielectric constant εdof the interlayer film102, the incident angle θ of light, and the hole pitch P1. Note that, in a case where the incident angle of light is 0°, the resonant wavelength and the resonant frequency of the plasmons are determined by the dielectric constant εmof the conductive thin film131A, the dielectric constant εdof the interlayer film102, and the hole pitch P1.

Accordingly, the transmission band of the plasmon filter121A (the plasmon resonant wavelength) varies depending on the material and the thickness of the conductive thin film131A, the material and the thickness of the interlayer film102, the pattern intervals of the hole array (the aperture diameter D1and the hole pitch P1of the holes132A, for example), and the like. In particular, in a case the materials and the thicknesses of the conductive thin film131A and the interlayer film102have been determined, the transmission band of the plasmon filter121A varies depending on the pattern intervals of the hole array, or more particularly, on the hole pitch P1. That is, as the hole pitch P1becomes narrower, the transmission band of the plasmon filter121A shifts to the shorter wavelength side. As the hole pitch P1becomes wider, the transmission band of the plasmon filter121A shifts to the longer wavelength side.

FIG. 7is a graph showing an example of the spectral characteristics of the plasmon filter121A in a case where the hole pitch P1is varied. In the graph, the abscissa axis indicates wavelength (unit: nm), and the ordinate axis indicates sensitivity (unit being selected as appropriate). A line L11indicates the spectral characteristics in a case where the hole pitch P1is set at 250 nm, a line L12indicates the spectral characteristics in a case where the hole pitch P1is set at 325 nm, and a line L13indicates the spectral characteristics in a case where the hole pitch P1is set at 500 nm.

In the case where the hole pitch P1is set at 250 nm, the plasmon filter121A primarily transmits light in the blue-color wavelength band. In the case where the hole pitch P1is set at 325 nm, the plasmon filter121A primarily transmits light in the green-color wavelength band. In the case where the hole pitch P1is set at 500 nm, the plasmon filter121A primarily transmits light in the red-color wavelength band. However, in the case where the hole pitch P1is set at 500 nm, the plasmon filter121A also transmits a large amount of light in lower wavelength bands than the red color, with the waveguide mode described later.

FIG. 8is a graph showing another example of the spectral characteristics of the plasmon filter121A in a case where the hole pitch P1is varied. In the graph, the abscissa axis indicates wavelength (unit: nm), and the ordinate axis indicates sensitivity (unit being selected as appropriate). This example is an example of 16 kinds of spectral characteristics of the plasmon filter121A in a case where the hole pitch P1is varied from 250 nm to 625 nm, at intervals of 25 nm.

Note that the transmittance of the plasmon filter121A is determined primarily by the aperture diameter D1of the holes132A. Where the aperture diameter D1is greater, the transmittance is greater, but color mixing is more likely to occur. It is normally preferable to set the aperture diameter D1so that the aperture ratio becomes 50% to 60% of the hole pitch P1.

Further, each hole132A of the plasmon filter121A functions as a waveguide, as described above. Therefore, depending on the pattern of the hole array of the plasmon filter121A, not only the wavelength component to be transmitted by surface plasmon resonance (the wavelength component in the plasmon mode), but also the wavelength component to pass through the holes132A (waveguides) (the wavelength component in the waveguide mode) might become large in the spectral characteristics.

FIG. 9shows the spectral characteristics of the plasmon filter121A in a case where the hole pitch P1is set at 500 nm, like the spectral characteristics represented by the line L13inFIG. 7. In this example, the longer wavelength side than the cutoff wavelength in the neighborhood of 630 nm is the wavelength component in the plasmon mode, and the shorter wavelength side than the cutoff wavelength is the wavelength component in the waveguide mode.

As described above, the cutoff wavelength depends primarily on the aperture diameter D1of the holes132A. The shorter the cutoff wavelength, the smaller the aperture diameter D1. Further, as the difference between the cutoff wavelength and the peak wavelength in the plasmon mode is made larger, the wavelength resolution characteristics of the plasmon filter121A improve.

Also, as described above, the higher the plasma frequency ωpof the conductive thin film131A, the higher the surface plasma frequency ωspof the conductive thin film131A. Also, the lower the dielectric constant εdof the interlayer film102, the higher the surface plasma frequency ωsp. Further, as the surface plasma frequency ωspbecomes higher, a higher plasmon resonant frequency can be set, and the transmission band of the plasmon filter121A (the plasmon resonant wavelength) can be set in a shorter wavelength band.

Accordingly, where a metal having a lower plasma frequency ωpis used for the conductive thin film131A, the transmission band of the plasmon filter121A can be set in a shorter wavelength band. For example, aluminum, silver, gold, or the like is preferable. However, in a case where a long wavelength band such as the wavelength band of infrared light is set as the transmission band, copper or the like can be used.

Also, where a dielectric material having a lower dielectric constant εdis used for the interlayer film102, the transmission band of the plasmon filter121A can be set in a shorter-wavelength band. For example, SiO2, a Low-k material, or the like is preferable.

FIG. 10is a graph showing the propagation characteristics of the surface plasmons at the interface between the conductive thin film131A and the interlayer film102in a case where aluminum is used for the conductive thin film131A, and SiO2 is used for the interlayer film102. In the graph, the abscissa axis indicates the wavelength of light (unit: nm), and the ordinate axis indicates the propagation distance (unit: μm). Further, a line L21indicates the propagation characteristics in the interfacial direction, a line L22indicates the propagation characteristics in the depth direction of the interlayer film102(a direction perpendicular to the interface), and a line L23indicates the depth direction of the conductive thin film131A (a direction perpendicular to the interface).

The propagation distance ΛSPP(λ) of the surface plasmons in the depth direction is expressed by Equation (6) shown below.

In the equation, kSPPrepresents the absorption coefficient of a substance through which the surface plasmons propagate. In the equation, εm(λ) represents the dielectric constant of the conductive thin film131A with respect to light having the wavelength λ. Further, εd(λ) represents the dielectric constant of the interlayer film102with respect to light having the wavelength λ.

Accordingly, the surface plasmons for light having a wavelength of 400 nm propagate from the surface of the interlayer film102including SiO2 to a depth of about 100 nm, as shown inFIG. 10. Thus, as the thickness of the interlayer film102is set at 100 nm or greater, the substance stacked on the surface on the opposite side of the interlayer film102from the conductive thin film131A is prevented from affecting the surface plasmons at the interface between the interlayer film102and the conductive thin film131A.

Also, the surface plasmons for light having a wavelength of 400 nm propagate from the surface of the conductive thin film131A including aluminum to a depth of about 10 nm. Thus, as the thickness of the conductive thin film131A is set at 10 nm or greater, the interlayer film104is prevented from affecting the surface plasmons at the interface between the interlayer film102and the conductive thin film131A.

A plasmon filter121B inFIG. 11Ais formed with a plasmon resonator in which holes132B are formed in an orthogonal matrix in a conductive thin film131B. In the plasmon filter121B, the transmission band varies depending on a pitch P2between adjacent holes132B, for example.

Meanwhile, in a plasmon resonator, not all the holes need to penetrate the conductive thin film. Even if some holes are formed with non-through holes that do not penetrate the conductive thin film, the plasmon resonator functions as a filter.

For example,FIG. 11Bshows a plan view and a cross-sectional view (taken along the line A-A′ defined in the plan view) of a plasmon filter121C formed with a plasmon resonator in which holes132C formed with through holes and holes132C′ formed with non-through holes are arranged in a honeycomb fashion in a conductive thin film131C. That is, the holes132C formed with through holes and holes132C′ formed with non-through holes are arranged at intervals in the plasmon filter121C.

Further, a single-layer plasmon resonator is normally used as a plasmon filter, but a plasmon filter may be formed with a two-layer plasmon resonator, for example.

For example, a plasmon filter121D shown inFIG. 12includes two layers: a plasmon filter121D-1and a plasmon filter121D-2. Like the plasmon resonator forming the plasmon filter121A shown inFIG. 5, the plasmon filter121D-1and the plasmon filter121D-2each have a structure in which holes are arranged in a honeycomb fashion.

Also, the distance D2between the plasmon filter121D-1and the plasmon filter121D-2is preferably about ¼ of the peak wavelength of the transmission band. Further, with the degree of freedom of design being taken into account, the distance D2is preferably equal to or shorter than ½ of the peak wavelength of the transmission band.

Note that, like the plasmon filter121D, the holes may be arranged in the same pattern in the plasmon filter121D-1and the plasmon filter121D-2, but the holes may be arranged in patterns similar to each other in a two-layer plasmon resonator structure, for example. Also, in a two-layer plasmon resonator structure, holes and dots may be arranged in such patterns that the hole array structure and the dot array structure (described later) are reversed structures. Further, the plasmon filter121D has a two-layer structure, but a three or more layers may be adopted.

Also, in the above description, example configurations of plasmon filters using plasmon resonators each having a hole array structure have been described. However, a plasmon resonator having a dot array structure may be adopted as a plasmon filter.

Referring now toFIGS. 13A and 13B, a plasmon filter having a dot array structure is described.

A plasmon filter121A′ inFIG. 13Ais formed with a negative-positive reversed structure of the plasmon resonator of the plasmon filter121A inFIG. 5, or is formed with a plasmon resonator in which dots133A are formed in a honeycomb fashion in a dielectric layer134A. Spaces between the respective dots133A are filled with the dielectric layer134A.

The plasmon filter121A′ absorbs light in a predetermined wavelength band, and therefore, is used as a complementary color filter. The wavelength band of light to be absorbed by the plasmon filter121A′ (this wavelength band will be hereinafter referred to as the absorption band) varies depending on the pitch P3between adjacent dots133A (this pitch will be hereinafter referred to as the dot pitch) and the like. Further, the diameter D3of the dots133A is adjusted in accordance with the dot pitch P3.

A plasmon filter121B′ inFIG. 13Bis formed with a negative-positive reversed structure of the plasmon resonator of the plasmon filter121B ofFIG. 11A, or is formed with a plasmon resonator structure in which dots133B are formed in an orthogonal matrix in a dielectric layer134B. Spaces between the respective dots133B are filled with the dielectric layer134B.

The absorption band of the plasmon filter121B′ varies depending on a dot pitch P4between adjacent dots133B or the like. Further, the diameter D3of the dots133B is adjusted in accordance with the dot pitch P4.

FIG. 14is a graph showing an example of the spectral characteristics in a case where the dot pitch P3of the plasmon filter121A′ inFIG. 13Ais varied. In the graph, the abscissa axis indicates wavelength (unit: nm), and the ordinate axis indicates transmittance. A line L31indicates the spectral characteristics in a case where the dot pitch P3is set at 300 nm, a line L32indicates the spectral characteristics in a case where the dot pitch P3is set at 400 nm, and a line L33indicates the spectral characteristics in a case where the dot pitch P3is set at 500 nm.

As shown in this drawing, as the dot pitch P3becomes narrower, the absorption band of the plasmon filter121A′ shifts to the shorter wavelength side. As the dot pitch P3becomes wider, the absorption band of the plasmon filter121A′ shifts to the longer wavelength side.

Further, in a plasmon filter having an array structure, rectangular squares can be used in place of circular dots.

FIG. 15shows a plasmon filter121E having a square array structure using rectangular squares135. That is, the plasmon filter121E has the rectangular squares135in place of the circular dots133B of the plasmon filter121B′ inFIG. 13B. Spaces between the respective squares135are filled with a dielectric layer136.

Likewise, the circular dots133A of the plasmon filter121A′ inFIG. 13Acan be replaced with rectangular squares.

Note that, in any of plasmon filters having a hole array structure, a dot array structure, or a square array structure, it is possible to adjust the transmission band or the absorption band simply by adjusting the pitch in the planar direction of the holes, the dots, or the squares. Accordingly, the pitch of the holes, the dots, or the squares is simply adjusted in the lithography process, for example, so that the transmission band or the absorption band can be set individually for each pixel, and the filters are turned into multiple colors in a fewer number of steps.

Further, the thickness of a plasmon filter is about 100 to 500 nm, which is almost similar to that of an organic color filter, and its affinity to the process is high.

Furthermore, a plasmon filter151using guided-mode resonant (GMR) shown inFIG. 16can be used as a narrowband filter NB.

In the plasmon filter151, a conductor layer161, a SiO2 film162, a SiN film163, and a SiO2 substrate164are stacked in this order from the top. The conductor layer161is included in the filter layer103inFIG. 4, for example, and the SiO2 film162, the SiN film163, and the SiO2 substrate164are included in the interlayer film104inFIG. 4, for example.

In the conductor layer161, rectangular conductive thin films161A including aluminum, for example, are arranged at a predetermined pitch P5, so that the long sides of the conductive thin films161A are adjacent to one another. The transmission band of the plasmon filter151then varies depending on the pitch P5or the like.

FIG. 17is a graph showing an example of the spectral characteristics of the plasmon filter151in a case where the pitch P5is varied. In the graph, the abscissa axis indicates wavelength (unit: nm), and the ordinate axis indicates transmittance. This example shows an example of the spectral characteristics in a case where the pitch P5is varied from 280 nm to 480 nm in six kinds at intervals of 40 nm, and the width of the slits between the adjacent conductive thin films161A is set at ¼ of the pitch P5. Further, the waveform having the shortest peak wavelength in the transmission band indicates the spectral characteristics in a case where the pitch P5is set at 280 nm. As the pitch P5becomes wider, the peak wavelength becomes longer. That is, as the pitch P5becomes narrower, the transmission band of the plasmon filter151shifts to the shorter wavelength side. As the pitch P5becomes wider, the transmission band of the plasmon filter151shifts to the longer wavelength side.

Like plasmon filters having the hole array structure and the dot array structure described above, this plasmon filter151using GMR also has a high affinity to organic color filters.

Further, a plasmon filter171using a bull's-eye structure shown inFIGS. 18A and 18Bcan be used as a narrowband filter NB. A bull's-eye structure has this name, because of its resemblance to a dart target or a bow and arrow target.

As shown inFIG. 18A, the plasmon filter171having a bull's-eye structure has a through hole181at its center, and includes a plurality of protruding portions182formed concentrically around the through hole181. That is, the plasmon filter171having a bull's-eye structure has a shape to which a metallic diffraction grating structure that causes plasmon resonance is applied.

The plasmon filter171having a bull's-eye structure has characteristics similar to those of the plasmon filter151using GMR. That is, in a case where the pitch between the protruding portions182is a pitch P6, the plasmon filter171has the following characteristics: the transmission band shifts to the shorter wavelength side as the pitch P6becomes narrower, and the transmission band shifts to the longer wavelength side as the pitch P6becomes wider.

2. First Embodiment of the Present Technology

FIG. 19schematically shows an example configuration of an imaging device12A including a filter layer103A that is the first embodiment of the filter layer103inFIG. 4.FIG. 19shows a cross-section of the ten pixels: normal pixels51A-1through51A-5, and narrowband pixels51B-1through51B-5in the vicinity of the boundary portion B1between the normal pixel region31A and the narrowband pixel region31B of the imaging device12A.

In the filter layer103A, the color filters CF in the normal pixel region31A are disposed in a different layer from that of the narrowband filters NB in the narrowband pixel region31B. Specifically, the color filters CF are disposed at higher locations than the narrowband filters NB, or are disposed closer to the light incident surface of the imaging device12A.

Although not shown in the drawing, a reflected light reduction unit31C is disposed in the interlayer film102or the filter layer103A, as described later with reference toFIG. 20B.

FIG. 20Ais an enlarged view of the region around the filter layer103A in the vicinity of the boundary portion B1of the imaging device12A shown inFIG. 19, and schematically shows the condition of incident light in a case where the reflected light reduction unit31C is not adopted.

As shown in this drawing, part of the incident light that has passed through the color filters CF enters the sidewall SW1of the narrowband filter NB at the boundary portion B1, and is irregularly reflected by the sidewall SW1. The light reflected irregularly by the sidewall SW1then enters the photodiodes PD of the normal pixels51A in the vicinity of the boundary portion B1. As a result, noise due to the reflected light is generated in the normal pixels51A in the vicinity of the boundary portion B1, and the characteristics of the imaging device12A (particularly, the normal pixels51A in the vicinity of the boundary portion B1) are degraded.

On the other hand, a black filter201A that is a light absorber is provided as the reflected light reduction unit31C, for example, as shown inFIG. 20B.

The black filter201A is formed with a black resist, carbon black, or the like, for example. The black filter201A is disposed at a higher location than the color filters CF and the narrowband filters NB (or is disposed closer to the light incident surface of the imaging device12A than the color filters CF and the narrowband filters NB) at the boundary portion B1. The black filter201A also overlaps at least part of the normal pixel51A-1and the narrowband pixel51B-1adjacent to the boundary portion B1, and covers at least part of the light incident surface of the color filter CF of the normal pixel51A-1and the light incident surface of the narrowband filter NB of the narrowband pixel51B-1.

This black filter201A absorbs incident light traveling toward the sidewall SW1, and reduces entrance of the incident light to the sidewall SW1. As a result, the light reflected by the sidewall SW1is reduced, and thus, entrance of the reflected light to the photodiodes PD in the normal pixel region31A and degradation of the characteristics of the normal pixels51A are reduced.

LikeFIG. 19,FIG. 21schematically shows an example configuration of an imaging device12B including a filter layer103B that is a second embodiment of the filter layer103inFIG. 4.

In the filter layer103B, the color filters CF in the normal pixel region31A are disposed in the same layer as the narrowband filters NB in the narrowband pixel region31B.

Although not shown in the drawing, a reflected light reduction unit31C is disposed in the interlayer film102or the filter layer103B, as described later with reference toFIG. 22B.

LikeFIG. 20A,FIG. 22Aschematically shows the condition of incident light in a case where the reflected light reduction unit31C is not adopted.

As shown in this drawing, part of the incident light that has entered the color filters CF enters the sidewall SW1of the narrowband filter NB at the boundary portion B1, and is irregularly reflected by the sidewall SW1. The light reflected irregularly by the sidewall SW1then enters the photodiodes PD of the normal pixels51A in the vicinity of the boundary portion B1. As a result, noise due to the reflected light is generated in the normal pixels51A in the vicinity of the boundary portion B1, and the characteristics of the imaging device12B (particularly, the normal pixels51A in the vicinity of the boundary portion B1) are degraded.

On the other hand, as shown inFIG. 22B, a black filter201B similar to the black filter201A inFIG. 20Bis provided as the reflected light reduction unit31C.

The black filter201B is disposed at a higher location than the color filters CF and the narrowband filters NB (or is disposed closer to the light incident surface of the imaging device12B than the color filters CF and the narrowband filters NB) at the boundary portion B1. The black filter201B also overlaps at least part of the normal pixel51A-1and the narrowband pixel51B-1adjacent to the boundary portion B1, and covers at least part of the light incident surface of the color filter CF of the normal pixel51A-1and the light incident surface of the narrowband filter NB of the narrowband pixel51B-1.

This black filter201B absorbs incident light traveling toward the sidewall SW1, and reduces entrance of the incident light to the sidewall SW1. As a result, the light reflected by the sidewall SW1is reduced, and thus, entrance of the reflected light to the photodiodes PD in the normal pixel region31A and degradation of the characteristics of the normal pixels51A are reduced.

LikeFIG. 19andFIG. 21,FIG. 23schematically shows an example configuration of an imaging device12C including a filter layer103C that is a third embodiment of the filter layer103inFIG. 4.

In the filter layer103C, while the narrowband filters NB are disposed in the narrowband pixel region31B, any color filter CF is not provided in the normal pixel region31A.

Although not shown in the drawing, a reflected light reduction unit31C is disposed in the interlayer film102or the filter layer103C, as described later with reference toFIG. 24B.

LikeFIGS. 20AandFIG. 22A,FIG. 24Aschematically shows the condition of incident light in a case where the reflected light reduction unit31C is not adopted.

As shown in this drawing, light that has entered the sidewall SW1of the narrowband filter NB at the boundary portion B1is irregularly reflected by the sidewall SW1. The light reflected irregularly by the sidewall SW1then enters the photodiodes PD of the normal pixels51A in the normal pixel region31A in the vicinity of the boundary portion B1. As a result, noise due to the reflected light is generated in the normal pixels51A in the vicinity of the boundary portion, and the characteristics of the imaging device12C (particularly, the normal pixels51A in the vicinity of the boundary portion B1) are degraded.

On the other hand, as shown inFIG. 24B, a black filter201C similar to the black filter201A inFIG. 20Band the black filter201B inFIG. 22Bis provided as the reflected light reduction unit31C.

The black filter201C is disposed at a higher location than the narrowband filters NB (or is disposed closer to the light incident surface of the imaging device12C than the narrowband filters NB) at the boundary portion B1. The black filter201C also overlaps at least part of the normal pixel51A-1and the narrowband pixel51B-1adjacent to the boundary portion B1, and covers at least part of the light incident surface of the color filter CF of the normal pixel51A-1and the light incident surface of the narrowband filter NB of the narrowband pixel51B-1.

This black filter201C absorbs incident light traveling toward the sidewall SW1, and reduces entrance of the incident light to the sidewall SW1. As a result, the light reflected by the sidewall SW1is reduced, and thus, entrance of the reflected light to the photodiodes PD in the normal pixel region31A and degradation of the characteristics of the normal pixels51A are reduced.

Note that the width of the black filters201A through201C in a direction perpendicular to the boundary portion B1can be changed as appropriate. However, if the width of the black filters201A through201C is too great, the invalid pixel region that no incident light enters becomes larger. On the other hand, if the width of the black filters201A through201C is too small, the reflected light reduction effect becomes smaller.

Therefore, the width of the black filters201A through201C is preferably adjusted as appropriate in accordance with the reflectance of the metallic thin films of the narrowband filters NB or the like. For example, the width of the black filters201A through201C is preferably set within a range of two to four pixels around the boundary portion B1.

For example,FIG. 25shows an example in which the black filter201A covers the four pixels51of two normal pixels51A and two narrowband pixels51B around the boundary portion B1.

Referring now toFIG. 26, the conditions for the amount of protrusion L1of the black filter201A from the boundary portion B1into the normal pixel region31A (the width of the black filter201A in the normal pixel region31A) are described.

Note that a distance d1indicates the distance between the bottom surface of the black filter201A on the opposite side from the light incident surface and the bottom surface of the narrowband filter NB on the opposite side from the light incident surface. An angle θ1indicates the angle between the sidewall SW1and the plane extending through the side of the bottom surface of the black filter201A on the side of the normal pixel region31A and the side of the bottom surface of the sidewall SW1.

Further, where the assumed value of the maximum incident angle of incident light on the sidewall SW1is represented by θmax, the amount of protrusion L1is preferably set so that θ1≥θmax is satisfied. That is, the amount of protrusion L1is preferably set so as to satisfy Equation (7) shown below.
L1≥d×tan(θ max)  (7)

Note that the maximum incident angle θmax is expressed by Equation (8) shown below.
θ max=(CRA+f-number maximum incident angle of light)×α  (8)

CRA represents the principal ray angle of light incident on the normal pixel51A-1adjacent to the boundary portion B1. The f-number maximum incident angle of light is the maximum value of the angles of respective light rays incident on the normal pixel51A-1to the principal ray in a case where the f-number of the optical system11is the minimum. In the equation, α is a coefficient equal to or greater than 1, and is a coefficient obtained by adding 1 to a margin that is set with the production variations of the optical systems11, the on-chip microlenses101, and the like taken into account.

Note that CRA in Equation (8) varies with the image height, and therefore, the maximum incident angle θmax also varies with the image height. In view of this, a maximum incident angle θmax may be determined for each image height, and the amount of protrusion L1may be varied with the image height on the basis of the determined maximum incident angle θmax, for example. Alternatively, the maximum incident angle θmax may be fixed at the minimum value in the imaging device12, for example, and the amount of protrusion L1may be fixed, regardless of the image height.

For the black filter201B inFIG. 22Band the black filter201C inFIG. 24B, the conditions for the amount of protrusion L1are determined by a similar calculation process.

Alternatively, the black filter201A may cover only the normal pixel region31A, as shown inFIG. 27, for example.

Further, as shown inFIG. 28, the black filter201A may cover only the narrowband pixel region31B, for example.

The contents ofFIGS. 27 and 28can be similarly applied to the black filter201B inFIG. 22Band the black filter201C inFIG. 24B.

Further, as shown inFIG. 29, an optical filter211in which two kinds of color filters, which are a red filter211R and a blue filter211B, are stacked may be used in place of the black filter201A, for example.

The red filter211R does not transmit light having a wavelength near blue, and the blue filter21B does not transmit light having a wavelength near red. Accordingly, as the red filter211R and the blue filter211B are stacked, an effect equal to that of the black filter201A can be expected.

Note that the optical filter211can also be used in place of the black filter201B inFIG. 22Band the black filter201C inFIG. 24B.

3. Second Embodiment of the Present Technology

Next, a second embodiment of the present technology is described, with reference toFIGS. 30 through 32.

FIG. 30shows the second embodiment of the reflected light reduction unit31C in the imaging device12A shown inFIG. 19. The embodiment inFIG. 30differs from the embodiment inFIG. 20Bin that a black filter221A is adopted in place of the black filter201A.

The black filter221A covers the sidewall SW1of the narrowband filter NB at the boundary portion B1, and absorbs light incident on the sidewall SW1. As a result, the light reflected by the sidewall SW1is reduced, and thus, entrance of the reflected light to the photodiodes PD in the normal pixel region31A and degradation of the characteristics of the normal pixels51A are reduced.

FIG. 31shows the second embodiment of the reflected light reduction unit31C in the imaging device12B shown inFIG. 21. The embodiment inFIG. 31differs from the embodiment inFIG. 22Bin that a black filter221B is adopted in place of the black filter201B.

The black filter221B covers the sidewall SW1of the narrowband filter NB between the color filter CF of the normal pixel51A-1and the narrowband filter NB of the narrowband pixel51B-1adjacent to the boundary portion B1, and absorbs light incident on the sidewall SW1. As a result, the light reflected by the sidewall SW1is reduced, and thus, entrance of the reflected light to the photodiodes PD in the normal pixel region31A and degradation of the characteristics of the normal pixels51A are reduced.

FIG. 32shows the second embodiment of the reflected light reduction unit31C in the imaging device12C shown inFIG. 23. The embodiment inFIG. 32differs from the embodiment inFIG. 24Bin that a black filter221C is adopted in place of the black filter201C.

The black filter221C covers the sidewall SW1of the narrowband filter NB at the boundary portion B1, and absorbs light incident on the sidewall SW1. As a result, the light reflected by the sidewall SW1is reduced, and thus, entrance of the reflected light to the photodiodes PD in the normal pixel region31A and degradation of the characteristics of the normal pixels51A are reduced.

Note that an optical filter in which a red filter and a blue filter are stacked as in the optical filter211inFIG. 29may be used in place of the black filters221A through221C inFIGS. 30 through 32.

Further, a black filter, or a light absorption filter formed with an optical filter in which a red filter and a blue filter are stacked does not need to cover the entire sidewall SW1of the narrowband filter NB at the boundary portion B1, and may cover only part of the sidewall SW1.

Alternatively, a light absorption filter may cover not only the sidewall SW1of the narrowband filter NB, but also the incident surface and/or the bottom surface of the narrowband filter NB. In this case, the light absorption filter may cover part of the incident surface and/or the bottom surface of the narrowband filter NB, or may cover the entire surface within a range of one to several pixels.

4. Third Embodiment of the Present Technology

Next, a third embodiment of the present technology is described, with reference toFIGS. 33 through 35.

FIG. 33shows the third embodiment of the reflected light reduction unit31C in the imaging device12A shown inFIG. 19. The embodiment inFIG. 33differs from the embodiment inFIG. 30in that the black filter221A is replaced with a low-reflection film231A.

Like the black filter221A, the low-reflection film231A covers the sidewall SW1of the narrowband filter NB at the boundary portion B1. The low-reflection film231A is formed with a material having a lower reflectance than at least the metal forming the narrowband filters NB, such as titanium nitride, tungsten, or titanium, for example.

With this arrangement, reflection of light incident on the sidewall SW1is reduced by the low-reflection film231A. As a result, entrance of the reflected light to the photodiodes PD in the normal pixel region31A and degradation of the characteristics of the normal pixels51A are reduced.

FIG. 34shows the third embodiment of the reflected light reduction unit31C in the imaging device12B shown inFIG. 21. The embodiment inFIG. 34differs from the embodiment inFIG. 31in that a low-reflection film231B is adopted in place of the black filter221B.

Like the black filter221B, the low-reflection film231B covers the sidewall SW1of the narrowband filter NB between the color filter CF of the normal pixel51A-1and the narrowband filter NB of the narrowband pixel51B-1adjacent to the boundary portion B1. With this arrangement, reflection of light incident on the sidewall SW1is reduced by the low-reflection film231B. As a result, entrance of the reflected light to the photodiodes PD in the normal pixel region31A and degradation of the characteristics of the normal pixels51A are reduced.

FIG. 35shows the third embodiment of the reflected light reduction unit31C in the imaging device12C shown inFIG. 23. The embodiment inFIG. 35differs from the embodiment inFIG. 32in that a low-reflection film231C is adopted in place of the black filter221C.

Like the black filter221C, the low-reflection film231C covers the sidewall SW1of the narrowband filter NB at the boundary portion B1. With this arrangement, reflection of light incident on the sidewall SW1is reduced by the low-reflection film231C. As a result, entrance of the reflected light to the photodiodes PD in the normal pixel region31A and degradation of the characteristics of the normal pixels51A are reduced.

Note that the low-reflection films231A through231C do not need to cover the entire sidewall SW1of the narrowband filter NB at the boundary portion B1, and may cover only part of the sidewall SW1.

Alternatively, the low-reflection films231A through231C may cover not only the sidewall SW1of the narrowband filter NB, but also the incident surface and/or the bottom surface of the narrowband filter NB. In this case, the low-reflection films231A through231C may cover part of the incident surface and/or the bottom surface of the narrowband filter NB, or may cover the entire surface within a range of one to several pixels.

5. Fourth Embodiment of the Present Technology

Next, a fourth embodiment of the present technology is described, with reference toFIGS. 36 through 39.

FIG. 36shows the fourth embodiment of the reflected light reduction unit31C in the imaging device12A shown inFIG. 19.

In this embodiment, the sidewall SW2of the narrowband filter NB at the boundary portion B1is inclined with respect to the boundary portion B1. The sidewall SW2is inclined so as to move away from the boundary portion B1toward the narrowband pixel region31B (the narrowband pixel51B-1) as the distance from the light incident surface of the narrowband filter NB becomes longer.

With this arrangement, light directly incident on the sidewall SW2decreases, and reflection of the incident light by the sidewall SW2is reduced. As a result, entrance of the reflected light to the photodiodes PD in the normal pixel region31A and degradation of the characteristics of the normal pixels51A are reduced.

FIG. 37shows the fourth embodiment of the reflected light reduction unit31C in the imaging device12B shown inFIG. 21.

In this embodiment, the sidewall SW2of the narrowband filter NB at the boundary portion B1is inclined with respect to the boundary portion B1, as in the embodiment shown inFIG. 36. With this arrangement, light directly incident on the sidewall SW2decreases, and reflection of the incident light by the sidewall SW2is reduced. As a result, entrance of the reflected light to the photodiodes PD in the normal pixel region31A and degradation of the characteristics of the normal pixels51A are reduced.

FIG. 38shows the fourth embodiment of the reflected light reduction unit31C in the imaging device12C shown inFIG. 23.

In this embodiment, the sidewall SW2of the narrowband filter NB at the boundary portion B1is inclined with respect to the boundary portion B1, as in the embodiments shown inFIGS. 36 and 37. With this arrangement, light directly incident on the sidewall SW2decreases, and reflection of the incident light by the sidewall SW2is reduced. As a result, entrance of the reflected light to the photodiodes PD in the normal pixel region31A and degradation of the characteristics of the normal pixels51A are reduced.

Referring now toFIG. 39, the conditions for the inclination angle θ2of the sidewall SW2with respect to the light incident surface of the narrowband filter NB are described.

The inclination angle θ2is preferably set so as to satisfy Equation (9) shown below.
θ2≤90°−θ max  (9)

Note that the maximum incident angle θmax is determined according to Equation (8) shown above.

Where the thickness of the narrowband filter NB is represented by d2, and the length of the sidewall SW2(an inclined surface) in the depth direction is represented by L2, Equation (10) shown below is satisfied.
tan θ2=d2/L2  (10)

According to Equations (9) and (10), the length L2of the sidewall SW2in the depth direction is preferably set so as to satisfy Equation (11) shown below.
L2≥d2/tan(90°−θ max)  (11)

Note that the maximum incident angle θmax in Equation (8) varies depending on the image height, as described above. In view of this, a maximum incident angle θmax may be determined for each image height, and the length L2may be varied with the image height on the basis of the determined maximum incident angle θmax, for example. Alternatively, the maximum incident angle θmax may be fixed at the minimum value in the imaging device12C, for example, and the length L2may be fixed, regardless of the image height.

6. Example Positions of the Reflected Light Reduction Unit31C in the Pixel Array31

FIGS. 40A, 40B, 40C, 40D, 41A, 41B, 41C, 41D, 42A, 42B, 42C, 42D, 43A, 43B, 43C, and 43Dshow examples in which part of an invalid pixel region31D around the normal pixel region31A (the effective pixel region) of the pixel array31is replaced with the narrowband pixel region31B. Note that optical black pixels are disposed in the invalid pixel region31D in some cases.

In each example shown inFIGS. 40A, 40B, 40C, and 40D, three of the four portions (the upper, lower, right, and left portions) of the invalid pixel region31D around the normal pixel region31A are replaced with the narrowband pixel region31B. The reflected light reduction unit31C is then disposed at the boundary portions between the narrowband pixel region31B, and the normal pixel region31A and the invalid pixel region31D. On the other hand, the reflected light reduction unit31C is not formed at the boundary portion between the normal pixel region31A and the invalid pixel region31D.

In each example shown inFIGS. 41A, 41B, 41C, and 41D, two of the four portions, which are the upper, lower, right, and left portions, of the invalid pixel region31D around the normal pixel region31A are replaced with the narrowband pixel region31B. The reflected light reduction unit31C is then disposed at the boundary portions between the narrowband pixel region31B, and the normal pixel region31A and the invalid pixel region31D. On the other hand, the reflected light reduction unit31C is not formed at the boundary portion between the normal pixel region31A and the invalid pixel region31D.

In each example shown inFIGS. 42A, 42B, 42C, and 42D, one of the four portions, which are the upper, lower, right, and left portions, of the invalid pixel region31D around the normal pixel region31A is replaced with the narrowband pixel region31B. The reflected light reduction unit31C is then disposed at the boundary portions between the narrowband pixel region31B, and the normal pixel region31A and the invalid pixel region31D. On the other hand, the reflected light reduction unit31C is not formed at the boundary portion between the normal pixel region31A and the invalid pixel region31D.

In each example shown inFIGS. 43A, 43B, 43C, and 43D, the narrowband pixel region31B is formed in an image circle301.

In the example shown inFIG. 43A, in the image circle301, the four sides of the normal pixel region31A are surrounded by the narrowband pixel region31B. The reflected light reduction unit31C is then disposed at the boundary portions between the narrowband pixel region31B, and the normal pixel region31A and the invalid pixel region31D. Further, the horizontal portions of the reflected light reduction unit31C extend to both the right and left ends of the pixel array31beyond the ends of the narrowband pixel region31B.

The example inFIG. 43Bdiffers from the example inFIG. 43Ain that the portions of the narrowband pixel region31B on the right and left sides of the normal pixel region31A, and the vertical portions of the reflected light reduction unit31C are removed.

The example inFIG. 43Cdiffers from the example inFIG. 43Ain that the portions of the narrowband pixel region31B on the upper and lower sides of the normal pixel region31A, and the horizontal portions of the reflected light reduction unit31C are removed.

The example inFIG. 43Ddiffers from the example inFIG. 43Ain that the portions of the narrowband pixel region31B on the right and lower sides of the normal pixel region31A, and the portions of the reflected light reduction unit31C on the right and lower sides of the normal pixel region31A are removed.

Note that, since the narrowband pixel region31B is formed in the image circle301, any unnecessary structure (such as a narrowband filter NB, for example) is not formed in any unnecessary portion, and thus, irregular reflection of light can be reduced or prevented.

In the example shown inFIG. 44, the outer peripheral portion of the normal pixel region31A is replaced with the narrowband pixel region31B. Accordingly, the periphery of the normal pixel region31A is surrounded by the narrowband pixel region31B. The reflected light reduction unit31C is then disposed at the boundary portion between the narrowband pixel region31B and the normal pixel region31A.

In each example shown inFIGS. 45A, 45B, 45C, and 45D, three of the four portions, which are the upper, lower, right, and left portions, of the outer peripheral portion of the normal pixel region31A are replaced with the narrowband pixel region31B. Accordingly, three of the four portions of the periphery of the normal pixel region31A are surrounded by the narrowband pixel region31B. The reflected light reduction unit31C is then disposed at the boundary portion between the narrowband pixel region31B and the normal pixel region31A. Further, each portion of the reflected light reduction unit31C extends to the upper and lower ends, or the right and left ends of the pixel array31. Therefore, the reflected light reduction unit31C is also disposed in the narrowband pixel region31B and the invalid pixel region31D.

In each example shown inFIGS. 46A, 46B, 46C, and 46D, two of the four portions, which are the upper, lower, right, and left portions, of the outer peripheral portion of the normal pixel region31A are replaced with the narrowband pixel region31B. Accordingly, two of the four portions of the periphery of the normal pixel region31A are surrounded by the narrowband pixel region31B. The reflected light reduction unit31C is then disposed at the boundary portion between the narrowband pixel region31B and the normal pixel region31A. Further, each portion of the reflected light reduction unit31C extends to the upper and lower ends, or the right and left ends of the pixel array31. Therefore, the reflected light reduction unit31C is also disposed in the narrowband pixel region31B and the invalid pixel region31D.

In each example shown inFIGS. 47A, 47B, 47C, and 47D, one of the four portions, which are the upper, lower, right, and left portions, of the outer peripheral portion of the normal pixel region31A is replaced with the narrowband pixel region31B. Accordingly, one of the four portions of the periphery of the normal pixel region31A is surrounded by the narrowband pixel region31B. The reflected light reduction unit31C is then disposed at the boundary portion between the narrowband pixel region31B and the normal pixel region31A. Further, each portion of the reflected light reduction unit31C extends to the upper and lower ends, or the right and left ends of the pixel array31. Therefore, the reflected light reduction unit31C is also disposed in the invalid pixel region31D.

FIGS. 48A, 48B, 48C, and 48Dshow examples in which both the normal pixel region31A and the invalid pixel region31D are partially replaced with the narrowband pixel region31B. Note that the dotted lines inFIGS. 48A48B,48C, and48D indicate the boundaries between the normal pixel region31A and the invalid pixel region31D before the replacement.

In the example inFIG. 48A, the narrowband pixel region31B is disposed at the left end and the lower end of the pixel array31. The reflected light reduction unit31C is then disposed at the boundary portions between the narrowband pixel region31B, and the normal pixel region31A and the invalid pixel region31D. Further, each portion of the reflected light reduction unit31C extends to the upper and lower ends, or the right and left ends of the pixel array31. Therefore, the reflected light reduction unit31C is also disposed in the narrowband pixel region31B.

In the example inFIG. 48B, the upper end portion and the left end portion of the normal pixel region31A are replaced with the narrowband pixel region31B. The narrowband pixel region31B also extends to the upper and lower ends or the right and left ends of the pixel array31, and part of the invalid pixel region31D is replaced with the narrowband pixel region31B. The reflected light reduction unit31C is then disposed at the boundary portion between the narrowband pixel region31B and the normal pixel region31A. Further, each portion of the reflected light reduction unit31C extends to the upper and lower ends, or the right and left ends of the pixel array31. Therefore, the reflected light reduction unit31C is also disposed in the narrowband pixel region31B and the invalid pixel region31D.

In the example inFIG. 48C, the upper end portion, the lower end portion, and the right end portion of the normal pixel region31A are replaced with the narrowband pixel region31B. The lower end portion and the right end portion of the invalid pixel region31D are also replaced with the narrowband pixel region31B. The reflected light reduction unit31C is then disposed at the boundary portion between the narrowband pixel region31B and the normal pixel region31A. Further, each portion of the reflected light reduction unit31C extends to the upper and lower ends, or the right and left ends of the pixel array31. Therefore, the reflected light reduction unit31C is also disposed in the narrowband pixel region31B and the invalid pixel region31D.

In the example inFIG. 48D, the upper end portion, the lower end portion, and the left end portion of the normal pixel region31A are replaced with the narrowband pixel region31B. The left end portion of the invalid pixel region31D is also replaced with the narrowband pixel region31B. The reflected light reduction unit31C is then disposed at the boundary portion between the narrowband pixel region31B and the normal pixel region31A. Further, each portion of the reflected light reduction unit31C extends to the upper and lower ends, or the right and left ends of the pixel array31. Therefore, the reflected light reduction unit31C is also disposed in the narrowband pixel region31B and the invalid pixel region31D.

FIGS. 49A, 49B, and 49Cshow examples in which the pixel array31is divided into the normal pixel region31A and the narrowband pixel region31B.

Specifically, in the example inFIG. 49A, the pixel array31is horizontally divided into the normal pixel region31A and the narrowband pixel region31B. The reflected light reduction unit31C is then disposed at the boundary portion between the narrowband pixel region31B and the normal pixel region31A.

In the example inFIG. 49B, the pixel array31is vertically divided into the normal pixel region31A and the narrowband pixel region31B. The reflected light reduction unit31C is then disposed at the boundary portion between the narrowband pixel region31B and the normal pixel region31A.

In the example inFIG. 49C, the pixel array31is divided into four regions, the normal pixel region31A is located at the upper right portion and the lower left portion, and the narrowband pixel region31B is located at the upper left portion and the lower right portion. The reflected light reduction unit31C is then disposed at the boundary portion between the narrowband pixel region31B and the normal pixel region31A.

FIGS. 50A, 50B, and 50Cshow examples in which the narrowband pixel region31B is formed in part of the normal pixel region31A.

Specifically, in the example inFIG. 50A, the narrowband pixel region31B is disposed at the lower left corner of the normal pixel region31A. The reflected light reduction unit31C is then disposed at the boundary portion between the narrowband pixel region31B and the normal pixel region31A.

In the example inkFIG. 50B, the narrowband pixel region31B is disposed in the normal pixel region31A. The reflected light reduction unit31C is then disposed so as to surround the narrowband pixel region31B.

In the example inFIG. 50C, a plurality of narrowband pixel regions31B is disposed in the normal pixel region31A. The reflected light reduction unit31C is then disposed so as to surround each narrowband pixel region31B.

As the reflected light reduction unit31C is disposed at least at the boundary portion between the normal pixel region31A and the narrowband pixel region31B in the above manner, the reflected light on the sidewall of the narrowband filter NB at the boundary portion can be reduced as described above.

Note that, if the narrowband pixel region31B is disposed in the invalid pixel region31D, it is possible to avoid a decrease in the number of pixels in the normal pixel region31A (the effective pixel region), a change in the angle of view, a change in the aspect ratio, and the like. Meanwhile, the image height of the narrowband pixel region31B becomes greater. Therefore, the lens aberration and the CRA become greater, and the characteristics of the narrowband pixels51B are degraded. Further, the oblique light component entering the narrowband pixels51B increases, and the irregular reflection component on the sidewall of the narrowband filter NB becomes larger. Therefore, to improve the characteristics of the imaging device (particularly, the characteristics of the narrowband pixels51B), the load of signal processing might increase.

On the other hand, if the narrowband pixel region31B is disposed in the normal pixel region31A, the lens aberration, the CRA, and the oblique light component become smaller, and degradation of the characteristics of the imaging device12can be reduced. Meanwhile, a decrease in the number of pixels in the normal pixel region31A, a change in the angle of view, a change in the aspect ratio, and the like are caused.

Therefore, it is preferable to position the narrowband pixel region31B, while taking into consideration the above advantages and disadvantages.

7. Fifth Embodiment of the Present Technology

Next, a fifth embodiment of the present technology is described, with reference toFIGS. 51, 52, 53, 54, 55A, 55B, 56A, 56B, 57A, and 57B. In the fifth embodiment, to reduce generation of flare, an antireflective film that reduces light reflection is provided on the light incident surface of each narrowband filter NB.

Referring first toFIG. 51, a cause of generation of flare in the imaging apparatus10using the imaging device12shown inFIG. 2is described.

In the example shown inFIG. 51, the imaging device12is disposed in a semiconductor chip402. Specifically, the semiconductor chip402is mounted on a substrate413, and its periphery is covered with sealing glass411and resin412. Light that has passed through a lens401provided in the optical system11shown inFIG. 1and the sealing glass411then enters the imaging device12.

Here, in a case where the narrowband filters NB of the filter layer103of the imaging device12are formed with plasmon filters, a conductive thin film made of a metal is formed on each plasmon filter, as described above. This conductive thin film has a high reflectance, and easily reflects light having a wavelength outside the transmission band. Part of the light reflected by the conductive thin film is then reflected by the sealing glass411or the lens401, for example, and re-enters the imaging device12. Although not shown inFIG. 51, part of the light reflected by the conductive thin film is also reflected by an optical filter such as an infrared cutoff filter, bonding wires, or the like, and re-enters the imaging device12. Flare is then generated by these rays of re-entering light. In particular, a plasmon filter using a hole array structure has a low aperture ratio, and therefore, flare is easily generated.

On the other hand, as shown inFIG. 52, an antireflective film421is provided on the light incident surface of each narrowband filter NB. The antireflective film421is formed with a black filter, for example.

This antireflective film421absorbs the light reflected by the conductive thin film of the narrowband filter NB. As a result, the reflected light is reflected by the sealing glass411, the lens401, or the like, and is prevented from re-entering the imaging device12. As a result, generation of flare is reduced or prevented.

FIG. 53andFIG. 54show a first example layout of the antireflective film421.FIG. 53shows an example layout of the antireflective film421in the entire pixel array31.FIG. 54shows an example layout of the antireflective film421in each narrowband pixel51B.

In this example, the antireflective film421is formed in a grid pattern in the narrowband pixel region31B, and the periphery of each narrowband pixel51B is surrounded by the antireflective film421.

The antireflective film421absorbs the light reflected by the conductive thin film of the narrowband filter NB of each narrowband pixel51B, and prevents generation of flare.

Further, the antireflective film421is not formed on the portions of the light incident surface of the narrowband filter NB through which incident light is to be transmitted. Thus, a preferred transmittance is maintained in the narrowband filter NB, and excellent characteristics are maintained in each narrowband pixel51B.

Note that, as the width of the antireflective film421(the width of the grids) becomes smaller, the sensitivity of each narrowband pixel51B becomes higher, but the effect to reduce reflected light becomes smaller. On the other hand, as the width of the antireflective film421(the width of the grids) becomes greater, the effect to reduce reflected light becomes larger, but the sensitivity of each narrowband pixel51B becomes lower. Therefore, it is preferable to adjust the width of the antireflective film421as appropriate, in accordance with the required specifications, performance, and the like.

In the example layout inFIG. 55A, a square portion of the antireflective film421is disposed at the portion where four narrowband pixels51B are adjacent to one another. Each vertex of the square portion of the antireflective film421is located on a side of each narrowband pixel51B. Further, the antireflective film421is not formed at the boundary portions other than the four corner portions of each narrowband pixel51B.

The example layout inFIG. 55Bis a combination of the example layout inFIG. 54and the example layout inFIG. 55A. That is, this example differs from the example layout inFIG. 55Ain that the antireflective film421is also disposed at the boundary portions other than the four corner portions of each narrowband pixel51B, and the periphery of each narrowband pixel51B is surrounded by the antireflective film421.

Therefore, in the example layout inFIG. 55A, the sensitivity of each narrowband pixel51B becomes higher, but the effect to reduce reflected light becomes smaller than in the example layout inFIG. 55B. Conversely, in the example layout inFIG. 55B, the effect to reduce reflected light becomes greater, but the sensitivity of each narrowband pixel51B becomes lower than in the example layout inFIG. 55A.

In the example layout inFIG. 56A, a four-vertex star-shaped portion of the antireflective film421is disposed at the portion where four narrowband pixels51B are adjacent to one another. Each vertex of the star-shaped portion of the antireflective film421is located on a side of each narrowband pixel51B. Further, the antireflective film421is not formed at the boundary portions other than the four corner portions of each narrowband pixel51B.

The example layout inFIG. 56Bis a combination of the example layout inFIG. 54and the example layout inFIG. 56A. That is, this example differs from the example layout inFIG. 56Ain that the antireflective film421is also disposed at the boundary portions other than the four corner portions of each narrowband pixel51B, and the periphery of each narrowband pixel51B is surrounded by the antireflective film421.

Therefore, in the example layout inFIG. 56A, the sensitivity of each narrowband pixel51B becomes higher, but the effect to reduce reflected light becomes smaller than in the example layout inFIG. 56B. Conversely, in the example layout inFIG. 56B, the effect to reduce reflected light becomes greater, but the sensitivity of each narrowband pixel51B becomes lower than in the example layout inFIG. 56A.

In the example layout inFIG. 57A, a four-vertex star-shaped portion of the antireflective film421is disposed at the portion where four narrowband pixels51B are adjacent to one another, as in the example layout inFIG. 56A. However, this example differs from the example layout inFIG. 56Ain that each vertex of the star-shaped portion is connected by a side on a circular arc. Further, the antireflective film421is not formed at the boundary portions other than the four corner portions of each narrowband pixel51B.

The example layout inFIG. 57Bis a combination of the example layout inFIG. 54and the example layout inFIG. 57A. That is, this example differs from the example layout inFIG. 57Ain that the antireflective film421is also disposed at the boundary portions other than the four corner portions of each narrowband pixel51B, and the periphery of each narrowband pixel51B is surrounded by the antireflective film421.

Therefore, in the example layout inFIG. 57A, the sensitivity of each narrowband pixel51B becomes higher, but the effect to reduce reflected light becomes smaller than in the example layout inFIG. 57B. Conversely, in the example layout inFIG. 57B, the effect to reduce reflected light becomes greater, but the sensitivity of each narrowband pixel51B becomes lower than in the example layout inFIG. 57A.

Note that the antireflective film421may be formed for each set of plural narrowband pixels51B, such as each two pixels in the vertical direction and each one pixel in the horizontal direction, each one pixel in the vertical direction and each two pixels in the horizontal direction, each two pixels in the vertical direction and each two pixels in the horizontal direction, or each three pixels in the vertical direction and each three pixels in the horizontal direction. In this case, the antireflective film421is not necessarily formed on all the narrowband pixels51B.

8. Modifications of the Filters of Normal Pixels51A and Narrowband Pixels51B

Next, modifications of the filters of normal pixels51A and narrowband pixels51B are described.

A combination of the non-metallic filter included in a normal pixel51A and the narrowband filter NB (a metallic filter) included in a narrowband pixel51B is not limited to the example described above, but may be changed as appropriate. For example, metallic filters other than the plasmon filters described above can be used as the narrowband filters NB.

For example,FIG. 58shows an example in which a Fabry-Perot501is used as the narrowband filter NB shown inFIG. 20B.

The Fabry-Perot501is also called a Fabry-Perot interferometer or an etalon, and a semitransparent film511A and a semitransparent film511B that are parallel to the light incident surface are disposed at a predetermined interval therein. When light is reflected multiple times between the semitransparent film511A and the semitransparent film511B, waves having the same phase then reinforce each other, and waves having different phases cancel each other. As a result, of the incident light, light of a particular wavelength is intensified, light of the other wavelengths is weakened, and the light of the particular wavelength is output.

Further, any non-metallic filter is not necessarily provided in the normal pixels51A, as described above.

9. Image Processing in the Imaging Apparatus10

Next, image processing in the imaging apparatus10is described.

For example, imaging modes may be set in the imaging apparatus10, so that types of images to be output by the imaging device12can be switched. For example, in a case where a mode A is set, the imaging device12outputs only normal images. In a case where a mode B is set, the imaging device12outputs only multispectral images. In a case where a mode C is set, the imaging device12outputs both normal images and multispectral images.

For example, the user then selects an appropriate imaging mode in accordance with the scene, or the imaging apparatus10automatically selects an appropriate imaging mode in accordance with the scene.

For example, an imaging mode is selected in accordance with the object distance. In a case where the object distance is several meters, for example, the mode A is set, and normal images are captured and output. Also, in a case where the object distance is several centimeters to several tens of centimeters, for example, the mode B is set, and multispectral images are captured and output. Further, in a case where the mode C is set, for example, both normal images and multispectral images are captured and output for objects at the same object distance.

Meanwhile, in a multispectral image, wavelength resolution and spatial resolution are in a trade-off relationship. This is because the number of pixels per wavelength or the pixel area decreases when the spatial resolution is increased.

Therefore, a two-dimensional multispectral image, a one-dimensional multispectral image, or a zero-dimensional multispectral image may be selectively used depending on the purpose of use.

Here, a two-dimensional multispectral image is an image that expresses an object with two-dimensionally arranged pixels. A one-dimensional multispectral image is an image that expresses an object with one-dimensionally arranged pixels. A zero-dimensional multispectral image is an image that shows the spectral characteristics (spectroscopic spectrum, for example) of an object.

A two-dimensional multispectral image has a high spatial resolution and allows an object to be visually recognized, but has a low wavelength resolution. On the other hand, a zero-dimensional multispectral image has a low spatial resolution and does not allow an object to be visually recognized, but has a high wavelength resolution.

Here, an example of a method for calculating the spectral characteristics of an object is described.

Where the matrix indicating observation data (the pixel value of each narrowband pixel51B) is represented by b, the matrix indicating the spectral characteristics of each narrowband pixel51B is represented by A, and the matrix indicating the spectral characteristics of the object (hereinafter, referred to as the object spectrum) is represented by x, the relationship among the observation data b, the spectral characteristics A, and the object spectrum x is expressed by Equation (12) shown below.
b=Ax(12)

The inverse problem of Equation (12) is then solved according to Equation (13), to determine the object spectrum x.
x=A−1b(13)

Here, the least absolute shrinkage and selection operators n(LASSO) estimation technique using a first-order norm may be used as a useful technique for solving the inverse problem of Equation (13), for example.

For example, where the LASSO estimation technique is used, Equation (14) shown below is established on the basis of Equation (12) described above.
[Mathematical Formula 6]
ÂLASSO=argminx{∥Ax−b∥2+λ∥Lx∥}(14)

Here, the second term on the right-hand side is called a regularization term or a penalty term, λ represents the regularization parameter, and L represents the regularization matrix.

Equation (15) shown below is then derived from Equation (14), so that the object spectrum x can be determined.
[Mathematical Formula 7]
{circumflex over (x)}=ÂLASSOb(15)

Note that, on the right-hand side of Equation (14), regularization terms may be increased, like the third term, the fourth term, . . . , and the nth term, for example.

Further, another useful technique for solving the inverse problem of Equation (13) is ridge regression using a second-order norm, for example.

Where ridge regression is used, for example, Equation (16) shown below is established on the basis of Equation (12) described above.
[Mathematical Formula 9]
Âridge=argminx{∥Ax−b∥2+λ2∥Lx∥2}  (16)

Here, the second term on the right-hand side is called a regularization term or a penalty term, λ represents the regularization parameter, and L represents the regularization matrix.

Equation (17) shown below is then derived from Equation (16), so that the object spectrum x can be determined.
[Mathematical Formula 9]
x=Âridgeb(17)

Note that, on the right-hand side of Equation (16), regularization terms may be increased, like the third term, the fourth term, . . . , and the nth term, for example.

10. Example Applications

Next, example applications of the present technology are described.

<Example Applications of the Present Technology>

For example, the present technology can be applied in various cases where light such as visible light, infrared light, ultraviolet light, or an X-ray is sensed, as shown inFIG. 59.

Devices that take images for appreciation activities, such as digital cameras and portable devices with camera functions.

Devices for transportation use, such as vehicle-mounted sensors that take images of the front, the back, the surroundings, the inside, and the like of an automobile to perform safe driving such as an automatic stop or recognize a driver's condition and the like, surveillance cameras for monitoring running vehicles and roads, and ranging sensors for measuring distances between vehicles or the like.

Devices to be used in conjunction with home electric appliances, such as television sets, refrigerators, and air conditioners, to take images of gestures of users and operate the appliances in accordance with the gestures.

Devices for medical care use and health care use, such as endoscopes and devices for receiving infrared light for angiography.

Devices for security use, such as surveillance cameras for crime prevention and cameras for personal authentication.

Devices for beauty care use, such as skin measurement devices that image the skin, and microscopes that image the scalp.

Devices for sporting use, such as action cameras and wearable cameras for sports and the like.

Devices for agricultural use, such as cameras for monitoring conditions of fields and crops.

In the description below, more specific example applications are described.

For example, the transmission band of the narrowband filter NB of each narrowband pixel51B of the imaging apparatus10shown inFIG. 1is adjusted, so that the wavelength band of light to be detected by each narrowband pixel51B of the imaging apparatus10(this wavelength band will be hereinafter referred to as the detection band) can be adjusted. The detection band of each narrowband pixel51B is then set as appropriate, or a plurality of multispectral images is then used, so that the imaging apparatus10can be used for various purposes.

For example, the imaging apparatus10can be used for detecting a particular index. Typical examples of such indices include the normalized difference vegetation index (NDVI), SPAD values, the photochemical reflectance index (PRI), the palmer drought severity index (SDVI), the normalized difference soil moisture index (NDSMI), the leaf-color verified index (LVI), DDVI, and the like. Such examples also include simple ratios (SR), the global environment monitoring index (GEMI), the soil adjusted vegetation index (SAVI), the enhanced vegetation index (EVI), the perpendicular vegetation index (PVI), the structure insensitive pigment index (SIPI), the plant senescing reflectance index (PSRI), the chlorophyll index (CI), modified simple ratios (mSR), modified normalized differences (mND), the canopy chlorophyll index (CCI), the water index (WI), the normalized difference water index (NDWI), the cellulose absorption index (CAI), and the like.

For example, it is possible to determine the NDVI according to Equation (18) shown below, using a near-infrared (NIR) image and a red (RED) image.
NDVI=(NIR-RED)/(NIR+RED)  (18)

Further,FIG. 60shows examples of the detection band in a case where the flavor and the degree of freshness of food are detected, for example.

For example, in a case where myoglobin indicating the flavor component of tuna, beef, or the like is detected, the peak wavelength of the detection band is in the range of 580 to 630 nm, and the half width is in the range of 30 to 50 nm. In a case where oleic acid indicating the degree of freshness of tuna, beef, or the like is detected, the peak wavelength of the detection band is 980 nm, and the half width is in the range of 50 to 100 nm. In a case where chlorophyll indicating the degree of freshness of a leafy vegetable such as “komatsuna” is detected, the peak wavelength of the detection band is in the range of 650 to 700 nm, and the half width is in the range of 50 to 100 nm.

FIG. 61shows examples of the detection band in a case where the sugar content and the water content of a fruit are detected.

For example, in a case where a flesh light path length indicating the sugar content of “raiden”, which is a kind of melon, is detected, the peak wavelength of the detection band is 880 nm, and the half width is in the range of 20 to 30 nm. In a case where sucrose indicating the sugar content of “raiden” is detected, the peak wavelength of the detection band is 910 nm, and the half width is in the range of 40 to 50 nm. In a case where sucrose indicating the sugar content of “raiden red”, which is another kind of melon, is detected, the peak wavelength of the detection band is 915 nm, and the half width is in the range of 40 to 50 nm. In a case where water content indicating the sugar content of “raiden red” is detected, the peak wavelength of the detection band is 955 nm, and the half width is in the range of 20 to 30 nm.

In a case where sucrose indicating the sugar content of an apple is detected, the peak wavelength of the detection band is 912 nm, and the half width is in the range of 40 to 50 nm. In a case where water indicating the water content of an orange is detected, the peak wavelength of the detection band is 844 nm, and the half width is 30 nm. In a case where sucrose indicating the sugar content of an orange is detected, the peak wavelength of the detection band is 914 nm, and the half width is in the range of 40 to 50 nm.

FIG. 62shows examples of the detection band in a case where plastics are separated.

For example, in a case where polyethylene terephthalate (PET) is detected, the peak wavelength of the detection band is 1669 nm, and the half width is in the range of 30 to 50 nm. In a case where polystyrene (PS) is detected, the peak wavelength of the detection band is 1688 nm, and the half width is in the range of 30 to 50 nm. In a case where polyethylene (PE) is detected, the peak wavelength of the detection band is 1735 nm, and the half width is in the range of 30 to 50 nm. In a case where polyvinyl chloride (PVC) is detected, the peak wavelength of the detection band is in the range of 1716 to 1726 nm, and the half width is in the range of 30 to 50 nm. In a case where polypropylene (PP) is detected, the peak wavelength of the detection band is in the range of 1716 to 1735 nm, and the half width is in the range of 30 to 50 nm.

The present technology can also be applied to freshness management for cut flowers, for example.

Further, the present technology can be applied to checking for foreign substances in foods, for example. For example, the present technology can be applied to detection of foreign substances such as skins, shells, stones, leaves, branches, and wood chips mixed in nuts and fruits such as almonds, blueberries, and walnuts. The present technology can also be applied to detection of foreign substances such as plastic pieces mixed in processed foods, beverages, and the like, for example.

Further, the present technology can be applied to detection of the normalized difference vegetation index (NDVI), which is a vegetation index, for example.

The present technology can also be applied to human detection, on the basis of a spectral shape in the neighborhood of a wavelength of 580 nm derived from hemoglobin of human skin, and/or a spectral shape in the neighborhood of a wavelength of 960 nm derived from melanin pigment contained in human skin, for example.

Further, the present technology can be applied to biometric detection (biometric authentication), user interfaces, prevention and monitoring of forgery of signatures and the like, and the like, for example.

<Example Application to an Electronic Apparatus>

FIG. 63is a diagram showing an example configuration of an electronic apparatus to which the present technology is applied.

An electronic apparatus600includes an optical system configuration unit601, a drive unit602, an imaging device603, and a signal processing unit604.

The optical system configuration unit601includes an optical lens and the like, and causes an optical image of an object to enter the imaging device603. The drive unit602controls the driving of the imaging device603by generating and outputting various kinds of timing signals related to the driving inside the imaging device603. The signal processing unit604performs predetermined signal processing on an image signal output from the imaging device603, and performs a process in accordance with the signal processing result. The signal processing unit604also outputs an image signal as the signal processing result to a subsequent stage, to record the image signal on a recording medium such as a solid-state memory, or transfer the image signal to a predetermined server via a predetermined network, for example.

Here, the imaging device12described above is used as the imaging device603. Thus, it is possible to capture an image with a higher image quality, and increase the accuracy in detecting spectral characteristics.

<Example Application to an Imaging Module>

The present technology can also be applied to an imaging module that is used for various kinds of electronic apparatuses such as an imaging apparatus, for example. An imaging module includes the imaging device12, an optical system (a lens or the like, for example) that causes the imaging device12to form an image of an object, and a signal processing unit (a DSP, for example) that processes a signal output from the imaging device12, for example.

<Example Application to an Endoscopic Surgery System>

The technology according to the present disclosure may also be applied to an endoscopic surgery system, for example.

FIG. 64is a diagram schematically showing an example configuration of an endoscopic surgery system to which the technology (the present technology) according to the present disclosure may be applied.

FIG. 64shows a situation where a surgeon (a physician)11131is performing surgery on a patient11132on a patient bed11133, using an endoscopic surgery system11000. As shown in the drawing, the endoscopic surgery system11000includes an endoscope11100, other surgical tools11110such as a pneumoperitoneum tube11111and an energy treatment tool11112, a support arm device11120that supports the endoscope11100, and a cart11200on which various kinds of devices for endoscopic surgery are mounted.

The endoscope11100includes a lens barrel11101that has a region of a predetermined length from the top end to be inserted into a body cavity of the patient11132, and a camera head11102connected to the base end of the lens barrel11101. In the example shown in the drawing, the endoscope11100is designed as a so-called rigid scope having a rigid lens barrel11101. However, the endoscope11100may be designed as a so-called flexible scope having a flexible lens barrel.

At the top end of the lens barrel11101, an opening into which an objective lens is inserted is provided. A light source device11203is connected to the endoscope11100, and the light generated by the light source device11203is guided to the top end of the lens barrel by a light guide extending inside the lens barrel11101, and is emitted toward the current observation target in the body cavity of the patient11132via the objective lens. Note that the endoscope11100may be a forward-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

An optical system and an imaging device are provided inside the camera head11102, and reflected light (observation light) from the current observation target is converged on the imaging device by the optical system. The observation light is photoelectrically converted by the imaging device, and an electrical signal corresponding to the observation light, or an image signal corresponding to the observation image, is generated. The image signal is transmitted as RAW data to a camera control unit (CCU)11201.

The CCU11201is formed with a central processing unit (CPU), a graphics processing unit (GPU), or the like, and collectively controls operations of the endoscope11100and a display device11202. Further, the CCU11201receives an image signal from the camera head11102, and subjects the image signal to various kinds of image processing, such as a development process (a demosaicing process), for example, to display an image based on the image signal.

Under the control of the CCU11201, the display device11202displays an image based on the image signal subjected to the image processing by the CCU11201.

The light source device11203is formed with a light source such as a light emitting diode (LED), for example, and supplies the endoscope11100with illuminating light for imaging the surgical site or the like.

An input device11204is an input interface to the endoscopic surgery system11000. The user can input various kinds of information and instructions to the endoscopic surgery system11000via the input device11204. For example, the user inputs an instruction or the like to change imaging conditions (such as the type of illuminating light, the magnification, and the focal length) for the endoscope11100.

A treatment tool control device11205controls driving of the energy treatment tool11112for tissue cauterization, incision, blood vessel sealing, or the like. A pneumoperitoneum device11206injects a gas into a body cavity of the patient11132via the pneumoperitoneum tube11111to inflate the body cavity, for the purpose of securing the field of view of the endoscope11100and the working space of the surgeon. A recorder11207is a device capable of recording various kinds of information about the surgery. A printer11208is a device capable of printing various kinds of information relating to the surgery in various formats such as text, images, graphics, and the like.

Note that the light source device11203that supplies the endoscope11100with the illuminating light for imaging the surgical site can be formed with an LED, a laser light source, or a white light source that is a combination of an LED and a laser light source, for example. In a case where a white light source is formed with a combination of RGB laser light sources, the output intensity and the output timing of each color (each wavelength) can be controlled with high precision. Accordingly, the white balance of an image captured by the light source device11203can be adjusted. Alternatively, in this case, laser light from each of the RGB laser light sources may be emitted onto the current observation target in a time-division manner, and driving of the imaging device of the camera head11102may be controlled in synchronization with the timing of the light emission. Thus, images corresponding to the respective RGB colors can be captured in a time-division manner. According to the method, a color image can be obtained without any color filter provided in the imaging device.

Further, the driving of the light source device11203may also be controlled so that the intensity of light to be output is changed at predetermined time intervals. The driving of the imaging device of the camera head11102is controlled in synchronism with the timing of the change in the intensity of the light, and images are acquired in a time-division manner and are then combined. Thus, a high dynamic range image with no black portions and no white spots can be generated.

Further, the light source device11203may also be designed to be capable of supplying light of a predetermined wavelength band compatible with special light observation. In special light observation, light of a narrower band than the illuminating light (or white light) at the time of normal observation is emitted, with the wavelength dependence of light absorption in body tissue being taken advantage of, for example. As a result, so-called narrowband light observation (narrowband imaging) is performed to image predetermined tissue such as a blood vessel in a mucosal surface layer or the like, with high contrast. Alternatively, in the special light observation, fluorescence observation for obtaining an image with fluorescence generated through emission of excitation light may be performed. In fluorescence observation, excitation light is emitted to body tissue so that the fluorescence from the body tissue can be observed (autofluorescence observation). Alternatively, a reagent such as indocyanine green (ICG) is locally injected into body tissue, and excitation light corresponding to the fluorescence wavelength of the reagent is emitted to the body tissue so that a fluorescent image can be obtained, for example. The light source device11203can be designed to be capable of suppling narrowband light and/or excitation light compatible with such special light observation.

FIG. 65is a block diagram showing an example of the functional configurations of the camera head11102and the CCU11201shown inFIG. 64.

The camera head11102includes a lens unit11401, an imaging unit11402, a drive unit11403, a communication unit11404, and a camera head control unit11405. The CCU11201includes a communication unit11411, an image processing unit11412, and a control unit11413. The camera head11102and the CCU11201are communicably connected to each other by a transmission cable11400.

The lens unit11401is an optical system provided at the portion connecting to the lens barrel11101. Observation light captured from the top end of the lens barrel11101is guided to the camera head11102, and enters the lens unit11401. The lens unit11401is formed with a combination of a plurality of lenses including a zoom lens and a focus lens.

The imaging unit11402is formed with an imaging device. The imaging unit11402may be formed with one imaging device (a so-called single-plate type), or may be formed with a plurality of imaging devices (a so-called multiple-plate type). In a case where the imaging unit11402is of a multiple-plate type, for example, image signals corresponding to the respective RGB colors may be generated by the respective imaging devices, and be then combined to obtain a color image. Alternatively, the imaging unit11402may be designed to include a pair of imaging devices for acquiring right-eye and left-eye image signals compatible with three-dimensional (3D) display. As the 3D display is conducted, the surgeon11131can grasp more accurately the depth of the body tissue at the surgical site. Note that, in a case where the imaging unit11402is of a multiple-plate type, a plurality of lens units11401is provided for the respective imaging devices.

Further, the imaging unit11402is not necessarily provided in the camera head11102. For example, the imaging unit11402may be provided immediately behind the objective lens in the lens barrel11101.

The drive unit11403is formed with an actuator, and, under the control of the camera head control unit11405, moves the zoom lens and the focus lens of the lens unit11401by a predetermined distance along the optical axis. With this arrangement, the magnification and the focal point of the image captured by the imaging unit11402can be adjusted as appropriate.

The communication unit11404is formed with a communication device for transmitting and receiving various kinds of information to and from the CCU11201. The communication unit11404transmits the image signal obtained as RAW data from the imaging unit11402to the CCU11201via the transmission cable11400.

The communication unit11404also receives a control signal for controlling the driving of the camera head11102from the CCU11201, and supplies the control signal to the camera head control unit11405. The control signal includes information about imaging conditions, such as information for specifying the frame rate of captured images, information for specifying the exposure value at the time of imaging, and/or information for specifying the magnification and the focal point of captured images, for example.

Note that the above imaging conditions such as the frame rate, the exposure value, the magnification, and the focal point may be appropriately specified by the user, or may be automatically set by the control unit11413of the CCU11201on the basis of an acquired image signal. In the latter case, the endoscope11100has a so-called auto-exposure (AE) function, an auto-focus (AF) function, and an auto-white-balance (AWB) function.

The camera head control unit11405controls the driving of the camera head11102, on the basis of a control signal received from the CCU11201via the communication unit11404.

The communication unit11411is formed with a communication device for transmitting and receiving various kinds of information to and from the camera head11102. The communication unit11411receives an image signal transmitted from the camera head11102via the transmission cable11400.

The communication unit11411also transmits a control signal for controlling the driving of the camera head11102, to the camera head11102. The image signal and the control signal can be transmitted through electrical communication, optical communication, or the like.

The image processing unit11412performs various kinds of image processing on an image signal that is RAW data transmitted from the camera head11102.

The control unit11413performs various kinds of control relating to display of an image of the surgical portion or the like captured by the endoscope11100, and a captured image obtained through imaging of the surgical site or the like. For example, the control unit11413generates a control signal for controlling the driving of the camera head11102.

The control unit11413also causes the display device11202to display a captured image showing the surgical site or the like, on the basis of the image signal subjected to the image processing by the image processing unit11412. In doing so, the control unit11413may recognize the respective objects shown in the captured image, using various image recognition techniques. For example, the control unit11413can detect the shape, the color, and the like of the edges of an object shown in the captured image, to recognize the surgical tool such as forceps, a specific body site, bleeding, the mist at the time of use of the energy treatment tool11112, and the like. When causing the display device11202to display the captured image, the control unit11413may cause the display device11202to superimpose various kinds of surgery aid information on the image of the surgical site on the display, using the recognition result. As the surgery aid information is superimposed and displayed, and thus, is presented to the surgeon11131, it becomes possible to reduce the burden on the surgeon11131, and enable the surgeon11131to proceed with the surgery in a reliable manner.

The transmission cable11400connecting the camera head11102and the CCU11201is an electrical signal cable compatible with electric signal communication, an optical fiber compatible with optical communication, or a composite cable thereof.

Here, in the example shown in the drawing, communication is performed in a wired manner using the transmission cable11400. However, communication between the camera head11102and the CCU11201may be performed in a wireless manner.

An example of an endoscopic surgery system to which the technique according to the present disclosure can be applied has been described above. The technology according to the present disclosure may be applied to the imaging unit11402of the camera head11102among the components described above, for example. Specifically, the imaging device12described above can be applied to the imaging unit10402, for example. This makes it possible to obtain an image of the surgical site with better image quality, and detect various kinds of indications, for example. Thus, the surgeon can check the surgical site in a more reliable manner.

Although an endoscopic surgery system has been described as an example herein, the technology according to the present disclosure may also be applied to a microscopic surgery system or the like, for example.

<Example Applications to Mobile Structures>

Further, the technology according to the present disclosure may be embodied as an apparatus mounted on any type of mobile structure, such as an automobile, an electrical vehicle, a hybrid electrical vehicle, a motorcycle, a bicycle, a personal mobility device, an airplane, a drone, a vessel, or a robot, for example.

FIG. 66is a block diagram schematically showing an example configuration of a vehicle control system that is an example of a mobile structure control system to which the technology according to the present disclosure may be applied.

A vehicle control system12000includes a plurality of electronic control units connected via a communication network12001. In the example shown inFIG. 66, the vehicle control system12000includes a drive system control unit12010, a body system control unit12020, an external information detection unit12030, an in-vehicle information detection unit12040, and an overall control unit12050. Further, a microcomputer12051, a sound/image output unit12052, and an in-vehicle network interface (I/F)12053are shown as the functional components of the overall control unit12050.

The drive system control unit12010controls operations of the devices related to the drive system of the vehicle according to various programs. For example, the drive system control unit12010functions as control devices such as a driving force generation device for generating a driving force of the vehicle such as an internal combustion engine or a driving motor, a driving force transmission mechanism for transmitting the driving force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

The body system control unit12020controls operations of the various devices mounted on the vehicle body according to various programs. For example, the body system control unit12020functions as a keyless entry system, a smart key system, a power window device, or a control device for various lamps such as a headlamp, a backup lamp, a brake lamp, a turn signal lamp, a fog lamp, or the like. In this case, the body system control unit12020can receive radio waves transmitted from a portable device that substitutes for a key, or signals from various switches. The body system control unit12020receives inputs of these radio waves or signals, and controls the door lock device, the power window device, the lamps, and the like of the vehicle.

The external information detection unit12030detects information about the outside of the vehicle equipped with the vehicle control system12000. For example, an imaging unit12031is connected to the external information detection unit12030. The external information detection unit12030causes the imaging unit12031to capture an image of the outside of the vehicle, and receives the captured image. On the basis of the received image, the external information detection unit12030may perform an object detection process for detecting a person, a vehicle, an obstacle, a sign, characters on the road surface, or the like, or perform a distance detection process.

The imaging unit12031is an optical sensor that receives light, and outputs an electrical signal corresponding to the amount of received light. The imaging unit12031can output an electrical signal as an image, or output an electrical signal as distance measurement information. Further, the light to be received by the imaging unit12031may be visible light, or may be invisible light such as infrared rays.

The in-vehicle information detection unit12040detects information about the inside of the vehicle. For example, a driver state detector12041that detects the state of the driver is connected to the in-vehicle information detection unit12040. The driver state detector12041includes a camera that captures an image of the driver, for example, and, on the basis of detected information input from the driver state detector12041, the in-vehicle information detection unit12040may calculate the degree of fatigue or the degree of concentration of the driver, or determine whether or not the driver is dozing off.

On the basis of the external/internal information acquired by the external information detection unit12030or the in-vehicle information detection unit12040, the microcomputer12051can calculate the control target value of the driving force generation device, the steering mechanism, or the braking device, and output a control command to the drive system control unit12010. For example, the microcomputer12051can perform cooperative control to achieve the functions of an advanced driver assistance system (ADAS), including vehicle collision avoidance or impact mitigation, follow-up running based on the distance between vehicles, vehicle speed maintenance running, vehicle collision warning, vehicle lane deviation warning, or the like.

The microcomputer12051can also perform cooperative control to conduct automatic driving or the like for autonomously running not depending on the operation of the driver, by controlling the driving force generation device, the steering mechanism, the braking device, or the like on the basis of information about the surroundings of the vehicle, the information having being acquired by the external information detection unit12030or the in-vehicle information detection unit12040.

The microcomputer12051can also output a control command to the body system control unit12020, on the basis of the external information acquired by the external information detection unit12030. For example, the microcomputer12051controls the headlamp in accordance with the position of the leading vehicle or the oncoming vehicle detected by the external information detection unit12030, and performs cooperative control to achieve an anti-glare effect by switching from a high beam to a low beam, or the like.

The sound/image output unit12052transmits an audio output signal and/or an image output signal to an output device that is capable of visually or audibly notifying the passenger(s) of the vehicle or the outside of the vehicle of information. In the example shown inFIG. 66, an audio speaker12061, a display unit12062, and an instrument panel12063are shown as output devices. The display unit12062may include an on-board display and/or a head-up display, for example.

FIG. 67is a diagram showing an example of installation positions of imaging units12031.

The imaging units12101,12102,12103,12104, and12105are provided at the following positions: the front end edge of a vehicle12100, a side mirror, the rear bumper, a rear door, an upper portion of the front windshield inside the vehicle, and the like, for example. The imaging unit12101provided on the front end edge and the imaging unit12105provided on the upper portion of the front windshield inside the vehicle mainly capture images ahead of the vehicle12100. The imaging units12102and12103provided on the side mirrors mainly capture images on the sides of the vehicle12100. The imaging unit12104provided on the rear bumper or a rear door mainly captures images behind the vehicle12100. The front images acquired by the imaging units12101and12105are mainly used for detection of a vehicle running in front of the vehicle12100, a pedestrian, an obstacle, a traffic signal, a traffic sign, a lane, or the like.

Note thatFIG. 67shows an example of the imaging ranges of the imaging units12101through12104. An imaging range12111indicates the imaging range of the imaging unit12101provided on the front end edge, imaging ranges12112and12113indicate the imaging ranges of the imaging units12102and12103provided on the respective side mirrors, and an imaging range12114indicates the imaging range of the imaging unit12104provided on the rear bumper or a rear door. For example, image data captured by the imaging units12101through12104are superimposed on one another, so that an overhead image of the vehicle12100viewed from above is obtained.

At least one of the imaging units12101through12104may have a function of acquiring distance information. For example, at least one of the imaging units12101through12104may be a stereo camera including a plurality of imaging devices, or may be an imaging device having pixels for phase difference detection.

For example, in accordance with distance information obtained from the imaging units12101through12104, the microcomputer12051calculates the distances to the respective three-dimensional objects within the imaging ranges12111through12114, and temporal changes in the distances (the speeds relative to the vehicle12100). In this manner, the three-dimensional object that is the closest three-dimensional object on the traveling path of the vehicle12100and is traveling at a predetermined speed (0 km/h or higher, for example) in substantially the same direction as the vehicle12100can be extracted as the vehicle running in front of the vehicle12100. Further, the microcomputer12051can set beforehand an inter-vehicle distance to be maintained in front of the vehicle running in front of the vehicle12100, and can perform automatic brake control (including follow-up stop control), automatic acceleration control (including follow-up start control), and the like. In this manner, it is possible to perform cooperative control to conduct automatic driving or the like to autonomously travel not depending on the operation of the driver.

For example, in accordance with the distance information obtained from the imaging units12101through12104, the microcomputer12051can extract three-dimensional object data concerning three-dimensional objects under the categories of two-wheeled vehicles, regular vehicles, large vehicles, pedestrians, utility poles, and the like, and use the three-dimensional object data in automatically avoiding obstacles. For example, the microcomputer12051classifies the obstacles in the vicinity of the vehicle12100into obstacles visible to the driver of the vehicle12100and obstacles difficult to visually recognize. Then, the microcomputer12051then determines collision risks indicating the risks of collision with the respective obstacles. If a collision risk is equal to or higher than a set value, and there is a possibility of collision, the microcomputer12051can output a warning to the driver via the audio speaker12061and the display unit12062, or can perform driving support for avoiding collision by performing forced deceleration or avoiding steering via the drive system control unit12010.

At least one of the imaging units12101through12104may be an infrared camera that detects infrared rays. For example, the microcomputer12051can recognize a pedestrian by determining whether or not a pedestrian exists in images captured by the imaging units12101through12104. Such pedestrian recognition is carried out through a process of extracting feature points from the images captured by the imaging units12101through12104serving as infrared cameras, and a process of performing a pattern matching on the series of feature points indicating the outlines of objects and determining whether or not there is a pedestrian, for example. If the microcomputer12051determines that a pedestrian exists in the images captured by the imaging units12101through12104, and recognizes a pedestrian, the sound/image output unit12052controls the display unit12062to display a rectangular contour line for emphasizing the recognized pedestrian in a superimposed manner. Further, the sound/image output unit12052may also control the display unit12062to display an icon or the like indicating the pedestrian at a desired position.

An example of a vehicle control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to the imaging units12031among the components described above, for example. Specifically, the imaging device12described above can be applied to the imaging units12031, for example. This makes it possible to obtain a captured image with better image quality, and detect various kinds of indications, for example. Thus, the accuracy of detection of the situations outside the vehicle, and the like become higher. Further, the imaging units12031can be made smaller in size, for example.

The following is a description of modifications of the above described embodiments of the present technology.

For example, in the imaging device12A shown inFIG. 19, the narrowband filters NB may be disposed at higher locations than the color filters CF. In this case, the color filters CF are manufactured before the narrowband filters NB, but the color filters CF have a lower heat resistance than that of the narrowband filters NB. Therefore, the limitations on the manufacturing process, particularly the limitations on the temperature, need to be taken into consideration in conducting the design and manufacture.

The above described embodiments of the present technology can also be combined as appropriate. It is also possible to combine three or more embodiments.

Further, in the first embodiment and the second embodiment, for example, a light absorber that is neither a black filter nor an optical filter in which a red filter and a blue filter are stacked may be used. Such a light absorber preferably absorbs at least light in the wavelength band to be detected by the photodiodes PD, and more preferably absorbs not only visible light but also ultraviolet light and infrared light.

The present technology can also be applied to a semiconductor device in which a pixel including a metallic filter and a pixel not including any metallic filter are adjacent to each other, and to all electronic apparatuses including the semiconductor device. For example, the present technology can be applied not only to the back-illuminated CMOS image sensor described above, but also to a front-illuminated CMOS image sensor, a charge coupled device (CCD) image sensor, an image sensor having a photoconductor structure including an organic photoelectric conversion film and a quantum dot structure, and the like.

The present technology can also be applied to solid-state imaging devices (imaging devices) described below as examples.

<Example Configuration of a Cross-Section of a Solid-State Imaging Device to Which the Technology According to the Present Disclosure Can Be Applied>

FIG. 68is a cross-sectional view of an example configuration of a solid-state imaging device to which the technology according to the present disclosure can be applied.

In the solid-state imaging device, a photodiode (PD)20019receives incident light20001that enters from the back surface (the upper surface in the drawing) side of a semiconductor substrate20018. Above the PD20019, a planarizing film20013, a filter layer20012, and a microlens20011are disposed. The incident light20001that has entered and sequentially passed through the respective components is received by a light receiving surface20017, so that photoelectric conversion is performed.

For example, in the PD20019, an n-type semiconductor region20020is formed as the charge storage region that stores electric charges (electrons). In the PD20019, the n-type semiconductor region20020is formed in p-type semiconductor regions20016and20041of the semiconductor substrate20018. On a side of the n-type semiconductor region20020, which is the front surface (the lower surface) side of the semiconductor substrate20018, a p-type semiconductor region20041having a higher impurity concentration than the back surface (the upper surface) side is disposed. That is, the PD20019has a hole-accumulation diode (HAD) structure, and the p-type semiconductor regions20016and20041are formed so as to reduce generation of dark current in the respective interfaces with the upper surface side and the lower surface side of the n-type semiconductor region20020.

In the semiconductor substrate20018, a pixel separation unit20030that electrically separates a plurality of pixels20010from one another is provided, and the PD20019is disposed in a region partitioned by the pixel separation unit20030. In a case where the solid-state imaging device is viewed from the upper surface side in the drawing, the pixel separation unit20030is formed in a grid-like form so as to be interposed between the plurality of pixels20010, for example, and the PD20019is formed in a region partitioned by this pixel separation unit20030.

In each PD20019, the anode is grounded. In the solid-state imaging device, signal charges (electrons, for example) stored by the PD20019are read out via a transfer Tr (MOSFET) (not shown) or the like, and are output as an electrical signal to a vertical signal line (VSL) (not shown).

A wiring layer20050is provided in the front surface (the lower surface) of the semiconductor substrate20018on the opposite side from the back surface (the upper surface) in which the respective components such as a light-blocking film20014, the filter layer20012, the microlens20011, and the like are provided.

The wiring layer20050includes wiring lines20051and an insulating layer20052, and is designed so that the wiring lines20051are electrically connected to each component in the insulating layer20052. The wiring layer20050is a so-called multilayer wiring layer, and is formed by alternately stacking interlayer insulating films constituting the insulating layer20052and the wiring lines20051a plurality of times. Here, respective wiring lines including a wiring line to a Tr for reading out electric charges from the PD20019, such as a transfer Tr, a VSL, and the like are stacked as the wiring lines20051via the insulating layer20052.

A support substrate20061is provided on the surface of the wiring layer20050on the opposite side from the side on which the PD20019is provided. For example, a substrate including a silicon semiconductor with a thickness of several hundreds of μm is provided as the support substrate20061.

The light-blocking film20014is disposed on the back surface (the upper surface in the drawing) side of the semiconductor substrate20018.

The light-blocking film20014is designed so as to block part of the incident light20001traveling from above the semiconductor substrate20018toward the back surface of the semiconductor substrate20018.

The light-blocking film20014is disposed above the pixel separation unit20030formed inside the semiconductor substrate20018. Here, the light-blocking film20014is disposed so as to protrude in a convex form from the back surface (the upper surface) of the semiconductor substrate20018via an insulating film20015such as a silicon oxide film. On the other hand, above the PD20019provided inside the semiconductor substrate20018, the light-blocking film20014is not disposed, but the portion is left open so that the incident light20001can enter the PD20019.

That is, in a case where the solid-state imaging device is viewed from the upper surface side in the drawing, the planar shape of the light-blocking film20014is a grid-like shape, and an opening through which the incident light20001travels to the light receiving surface20017is formed.

The light-blocking film20014is formed with a light-blocking material that blocks light. For example, a titanium (Ti) film and a tungsten (W) film are stacked in this order, to form the light-blocking film20014. Alternatively, a titanium nitride (TiN) film and a tungsten (W) film are stacked in this order, to form the light-blocking film20014, for example.

The light-blocking film20014is covered with the planarizing film20013. The planarizing film20013is formed with an insulating material that passes light.

The pixel separation unit20030has a groove portion20031, a fixed charge film20032, and an insulating film20033.

The fixed charge film20032is formed so as to cover the groove portion20031that partitions the plurality of pixels20010, on the back surface (upper surface) side of the semiconductor substrate20018.

Specifically, the fixed charge film20032is designed to have a constant thickness and cover the inner surface of the groove portion20031formed on the back surface (upper surface) side of the semiconductor substrate20018. The insulating film20033is then provided (buried) so as to fill the inside of the groove portion20031covered with the fixed charge film20032.

Here, the fixed charge film20032is formed with a high dielectric material having negative fixed charges, so that a positive charge (hole) storage region is formed at the interface with the semiconductor substrate20018, and generation of dark current is reduced. As the fixed charge film20032is formed to have negative fixed charges, an electric field is applied to the interface with the semiconductor substrate20018by the negative fixed charges, and thus, a positive charge (hole) storage region is formed.

The fixed charge film20032can be formed with a hafnium oxide film (HfO2 film), for example. Alternatively, the fixed charge film20032can be formed to include at least one of oxides of hafnium, zirconium, aluminum, tantalum, titanium, magnesium, yttrium, a lanthanoid, or the like, for example.

In the filter layer20012, a color filter and a narrowband filter made of a metal are provided as described above, for example.

<Example Configuration of a Cross-Section of the Pixel Separation Unit of a Solid-State Imaging Device to Which the Technology According to the Present Disclosure Can Be Applied>

FIG. 68described above also shows a first example configuration of the pixel separation unit of a solid-state imaging device to which the technology according to the present disclosure can be applied.

Specifically, the pixel separation unit20030is formed with an insulating material so as to partition the plurality of pixels20010, and electrically separates the plurality of pixels20010from one another.

The pixel separation unit20030includes the groove portion20031, the fixed charge film20032, and the insulating film20033, and is formed so as to be buried in the semiconductor substrate20018on the side of the back surface (the upper surface in the drawing) of the semiconductor substrate20018.

That is, on the back surface (upper surface) side of the semiconductor substrate20018, the groove portion20031is formed so as to partition the n-type semiconductor regions20020forming the charge storage regions of the PDs20019. The inside of the groove portion20031is covered with the fixed charge film20032, and the groove portion20031is further filled with the insulating film20033, to form the pixel separation unit20030.

In a case where the solid-state imaging device is viewed from the upper surface side in the drawing, the planar shape of the pixel separation unit20030is a grid-like shape, and is interposed between the plurality of pixels20010. The PDs20019are then formed in the rectangular regions partitioned by the grid-like pixel separation unit20030.

For example, a silicon oxide film (SiO), a silicon nitride film (SiN), or the like can be used as the insulating film20033of the pixel separation unit20030. The pixel separation unit20030may be formed by shallow trench isolation, for example.

FIG. 69is a cross-sectional view of a second example configuration of the pixel separation unit of a solid-state imaging device to which the technology according to the present disclosure can be applied.

InFIG. 69, a first fixed charge film21212, a second fixed charge film21213, a first insulating film21214, and a second insulating film21215are buried in this order in a groove portion21211, to form a pixel separation unit21210that separates pixels21200from one another. The groove portion21211is formed to have a tapered cross-sectional shape so that the aperture diameter becomes smaller in the depth direction of a substrate21221.

Note that it is possible to form the pixel separation unit21210by burying the first fixed charge film21212, the second fixed charge film21213, the first insulating film21214, and the second insulating film21215not in this order in the groove portion21211. For example, it is possible to form the pixel separation unit21210by alternately burying insulating films and fixed charge films in the groove portion21211, such as burying the first insulating film21214, the first fixed charge film21212, the second insulating film21215, and the second fixed charge film21213in this order.

FIG. 70is a cross-sectional view of a third example configuration of the pixel separation unit of a solid-state imaging device to which the technology according to the present disclosure can be applied.

In the solid-state imaging device inFIG. 70, a pixel separation unit21310that separates the pixels21200from one another has a hollow structure. In this aspect, the solid-state imaging device inFIG. 70differs from the case shown inFIG. 69where the pixel separation unit21210does not have a hollow structure. The solid-state imaging device inFIG. 70does not have a tapered groove portion21311. In this aspect, the solid-state imaging device inFIG. 70also differs from the case shown inFIG. 69where the groove portion21211has a tapered shape. Note that the groove portion21311can be formed in a tapered shape like the groove portion21211shown inFIG. 69.

The pixel separation unit21310is formed by burying a fixed charge film21312and an insulating film21313in this order in the groove portion21311formed in the depth direction from the back surface side (the upper side) of the substrate21221. A hollow portion (a so-called void)21314is formed inside the groove portion21311.

That is, the fixed charge film21312is formed on the inner wall surface of the groove portion21311and the back surface side of the substrate21221, and the insulating film21313is formed so as to cover the fixed charge film21312. Further, to form the hollow portion21314in the groove portion21311, the insulating film21313is formed to have such a film thickness that does not completely fill the groove portion21311inside the groove portion21311, and is formed so as to close the groove portion21311at the opening end of the groove portion21311. The insulating film21313can be formed with a material such as silicon oxide, silicon nitride, silicon oxynitride, or resin, for example.

<Example Configuration of a Stacked Solid-State Imaging Device to Which the Technology According to the Present Disclosure Can Be Applied>

FIGS. 71A, 71B, and 71Care diagrams showing outlines of example configurations of stacked solid-state imaging devices to which the technology according to the present disclosure can be applied.

FIG. 71shows a schematic example configuration of a non-stacked solid-state imaging device. As shown inFIG. 71A, a solid-state imaging device23010has one die (a semiconductor substrate)23011. A pixel region23012in which pixels are arranged in an array, a control circuit23013that controls driving of the pixels and performs other various kinds of control, and a logic circuit23014for performing signal processing are mounted on the die23011.

FIGS. 71B and 71Cshow schematic example configurations of a stacked solid-state imaging device. As shown inFIGS. 71B and 71C, a solid-state imaging device23020is designed as a single semiconductor chip in which two dies, which are a sensor die23021and a logic die23024, are stacked and are electrically connected.

InFIG. 71B, the pixel region23012and the control circuit23013are mounted on the sensor die23021, and the logic circuit23014including a signal processing circuit that performs signal processing is mounted on the logic die23024.

InFIG. 71C, the pixel region23012is mounted on the sensor die23021, and the control circuit23013and the logic circuit23014are mounted on the logic die23024.

FIG. 72is a cross-sectional view showing an example configuration of the stacked solid-state imaging device23020.

In the sensor die23021, photodiodes (PDs) forming the pixels constituting the pixel region23012, floating diffusions (FDs), Trs (MOSFETs), Trs serving as the control circuit23013, and the like are formed. A wiring layer23101having a plurality of layers, which are three layers of wiring lines23110in this example, is further formed in the sensor die23021. Note that (the Trs to be) the control circuit23013can be formed in the logic die23024, instead of the sensor die23021.

In the logic die23024, Trs constituting the logic circuit23014are formed. A wiring layer23161having a plurality of layers, which are three layers of wiring lines23170in this example, is further formed in the logic die23024. In the logic die23024, a connecting hole23171having an insulating film23172formed on its inner wall surface is also formed, and a connected conductor23173connected to the wiring lines23170and the like is buried in the connecting hole23171.

The sensor die23021and the logic die23024are bonded so that the respective wiring layers23101and23161face each other. Thus, the stacked solid-state imaging device23020in which the sensor die23021and the logic die23024are stacked is formed. For example, the sensor die23021and the logic die23024are stacked so that the wiring lines23110and23170are in direct contact, and heat is then applied while a required load is applied, so that the wiring lines23110and23170are bonded directly to each other. Thus, the solid-state imaging device23020is formed.

In the sensor die23021, a connecting hole23111is formed. The connecting hole23111penetrates the sensor die23021from the back surface side (the side at which light enters the PDs) (the upper side) of the sensor die23021, and reaches the wiring lines23170in the uppermost layer of the logic die23024. A connecting hole23121that is located in the vicinity of the connecting hole23111and reaches the wiring lines23110in the first layer from the back surface side of the sensor die23021is further formed in the sensor die23021. An insulating film23112is formed on the inner wall surface of the connecting hole23111, and an insulating film23122is formed on the inner wall surface of the connecting hole23121. Connected conductors23113and23123are then buried in the connecting holes23111and23121, respectively. The connected conductor23113and the connected conductor23123are electrically connected on the back surface side of the sensor die23021. Thus, the sensor die23021and the logic die23024are electrically connected via the wiring layer23101, the connecting hole23121, the connecting hole23111, and the wiring layer23161.

FIG. 73is a cross-sectional view showing another example configuration of a stacked solid-state imaging device to which the technology according to the present disclosure can be applied.

InFIG. 73, a solid-state imaging device23401has a three-layer stack structure in which the three dies of a sensor die23411, a logic die23412, and a memory die23413are stacked.

The memory die23413includes a memory circuit that stores data to be temporarily required in signal processing to be performed in the logic die23412, for example.

InFIG. 73, the logic die23412and the memory die23413are stacked in this order under the sensor die23411. However, the logic die23412and the memory die23413may be stacked in reverse order. In other words, the memory die23413and the logic die23412can be stacked in this order under the sensor die23411.

Note that, inFIG. 73, PDs serving as the photoelectric conversion units of the pixels, and the source/drain regions of the pixels Tr are formed in the sensor die23411.

A gate electrode is formed around a PD via a gate insulating film, and the gate electrode and a pair of source/drain regions form a pixel Tr23421and a pixel Tr23422.

The pixel Tr23421adjacent to the PD is a transfer Tr, and one of the source/drain regions constituting the pixel Tr23421is an FD.

Further, an interlayer insulating film is formed in the sensor die23411, and a connecting hole is formed in the interlayer insulating film. In the connecting hole, a connected conductor23431connected to the pixel Tr23421and the pixel Tr23422is formed.

Further, a wiring layer23433having a plurality of layers of wiring lines23432connected to each connected conductor23431is formed in the sensor die23411.

Aluminum pads23434serving as electrodes for external connection are also formed in the lowermost layer of the wiring layer23433in the sensor die23411. That is, in the sensor die23411, the aluminum pads23434is formed at positions closer to the bonding surface23440with the logic die23412than the wiring lines23432. Each aluminum pad23434is used as one end of a wiring line related to inputting/outputting of signals from/to the outside.

Further, a contact23441to be used for electrical connection with the logic die23412is formed in the sensor die23411. The contact23441is connected to a contact23451of the logic die23412, and also to an aluminum pad23442of the sensor die23411.

Further, a pad hole23443is formed in the sensor die23411so as to reach the aluminum pad23442from the back surface side (the upper side) of the sensor die23411.

<Example Configuration of a Solid-State Imaging Device Sharing a Plurality of Pixels to Which the Technology According to the Present Disclosure Can Be Applied>

FIG. 74is a plan view showing an example configuration of a solid-state imaging device that shares a plurality of pixels to which the technology according to the present disclosure can be applied.FIG. 75is a cross-sectional view taken along the line A-A defined inFIG. 74.

A solid-state imaging device24010has a pixel region24011in which pixels are arranged in a two-dimensional array. The pixel region24011is designed such that a total of four pixels, which are two pixels in the horizontal direction and two pixels in the vertical direction, form a sharing pixel unit24012that shares a pixel Tr (MOSFET) and the like, and the sharing pixel units24012are arranged in a two-dimensional array.

The four pixels of a 4-pixel-sharing pixel unit24012that shares the four pixels, which are two pixels in the horizontal and two pixels in the vertical direction, include photodiodes (PDs)240211,240212,240213, and240214, respectively, and shares one floating diffusion (FD)24030. The sharing pixel unit24012also includes pixel Trs that are transfer Trs24041ifor the PDs24021i(i=1, 2, 3, and 4), and shared Trs to be shared by the four pixels, which are a reset Tr24051, an amplification Tr24052, and a selection Tr24053.

The FD24030is disposed at the center surrounded by the four PDs240211through240214. The FD24030is connected to a source/drain region S/D serving as the drain of the reset Tr24051and to the gate G of the amplification Tr24052via a wiring line24071. Each transfer Tr24041ihas a gate24042idisposed between the PD24021ifor the transfer Tr24041iand the FD24030adjacent to the PD24021i, and operates in accordance with a voltage applied to the gate24042i.

Here, the region including the PDs240211through240214, the FD24030, and the transfer Trs240411through240414of the sharing pixel units24012for each row is called a PD formation region24061. Also, the region including the reset Tr24051, the amplification Tr24052, and the selection Tr24053that are shared by four pixels among the pixel Trs of the sharing pixel units24012of each row is called a Tr formation region24062. The respective Tr formation regions24062and the respective PD formation regions24061that are continuous in the horizontal direction are alternately disposed in the vertical direction of the pixel region24011.

The reset Tr24051, the amplification Tr24052, and the selection Tr24053each include a pair of source/drain regions S/D and a gate G. One of the two source/drain regions S/D functions as a source, and the other functions as a drain.

The PDs240211through240214, the FD24030, the transfer Trs240411through240414, the reset Tr24051, the amplification Tr24052, and the selection Tr24053are formed in a p-type semiconductor region (p-well)24210formed on an n-type semiconductor substrate24200, for example, as shown in the cross-sectional view inFIG. 75.

As shown inFIG. 74, a pixel separation unit24101is formed in each PD formation region24061, and a device separation unit24102is formed in (the region including) each Tr formation region24062. As shown inFIG. 75, for example, the device separation unit24102includes a p-type semiconductor region24211formed in the p-type semiconductor region24210, and an insulating film (a silicon oxide film, for example)24212disposed on the surface of the p-type semiconductor region24211. Although not shown in the drawings, each pixel separation unit24101can have a similar configuration.

In the pixel region24011, well contacts24111for applying a fixed voltage to the p-type semiconductor region24210are formed. The well contacts24111can be designed as p-type semiconductor regions that are impurity diffusion regions formed on the surfaces of p-type semiconductor regions24231formed in the p-type semiconductor region24210. The well contacts24111are p-type semiconductor regions having a higher impurity concentration than the p-type semiconductor regions24231. The well contacts24111(and the p-type semiconductor regions24231under the well contacts24111) also serve as the device separation units24102, and are formed between the shared Trs (the reset Trs24051, the amplification Trs24052, and the selection Trs24053) of the sharing pixel units24012horizontally adjacent to each other. The well contacts24111are connected to a predetermined wiring line24242in a wiring layer24240via conductive vias24241. A predetermined fixed voltage is applied to the p-type semiconductor region24210from the wiring line24242through the conductive vias24241and the well contacts24111. A plurality of layers of wiring lines24242is disposed via an insulating film24243, to form the wiring layer24240. Although not shown in the drawings, narrowband filters, color filters, and microlenses are formed on the wiring layer24240via a planarizing film.

FIG. 76is a diagram showing an example of an equivalent circuit of a sharing pixel unit24012that shares four pixels. In the equivalent circuit of the sharing pixel unit24012that shares four pixels, the four PDs240211through240214are connected to the sources of the corresponding four transfer Trs240411through240414, respectively. The drain of each transfer Tr24041iis connected to the source of the reset Tr24051. The drain of each transfer Tr24041iis the common FD24030. The FD24030is connected to the gate of amplification Tr24052. The source of the amplification Tr24052is connected to the drain of the selection Tr24053. The drain of the reset Tr24051and the drain of the amplification Tr24052are connected to a power supply VDD. The source of the selection Tr24053is connected to a vertical signal line (VSL).

Note that the technology according to the present disclosure can be applied not only to the examples described above, but also to a solid-state imaging device that shares a plurality of pixels in any appropriate arrangement such as two pixels in the horizontal direction and four pixels in the vertical direction, or one pixel in the horizontal direction and four pixels in the vertical direction, for example.

Further, a plurality of pixels may be shared in the normal pixel region and/or the narrowband pixel region, to reduce the area of the transistors. With this arrangement, the light reception area becomes larger, and thus, a higher image quality and a higher accuracy in detecting spectral characteristics are achieved, for example. Alternatively, the number of pixels may be increased, to achieve a higher resolution.

The technology according to the present disclosure can be applied to the solid-state imaging devices as described above.

Note that, in the filter layers shown inFIGS. 69, 70, 72, and73, for example, color filters and metallic narrowband filters are provided, as in the filter layer20012shown inFIG. 68.

Note that embodiments of the present technology are not limited to the embodiments described above, and various modifications may be made to them without departing from the scope of the present technology.

The present technology can also be embodied in the configurations described below, for example.

A semiconductor device including:

a pixel unit in which a first pixel including a metallic filter and a second pixel not including the metallic filter are disposed adjacent to each other; and

a reflected light reduction unit that reduces reflected light on a sidewall of the metallic filter at a boundary portion between the first pixel and the second pixel.

The semiconductor device according to (1), in which

the reflected light reduction unit is disposed at a position closer to a light incident surface of the semiconductor device than the metallic filter, and includes a light absorber that overlaps at least one of the first pixel or the second pixel adjacent to the boundary portion.

The semiconductor device according to (2), in which

the second pixel includes a non-metallic filter, and

the light absorber is disposed at a position closer to the light incident surface of the semiconductor device than the metallic filter and the non-metallic filter.

The semiconductor device according to (3), in which

the non-metallic filter is disposed at a position closer to the light incident surface of the semiconductor device than the metallic filter.

The semiconductor device according to (2) or (3), in which

the light absorber is a black filter. (6)

The semiconductor device according to (2) or (3), in which

the light absorber is an optical filter in which a red filter and a blue filter are stacked.

The semiconductor device according to any one of (2) to (6), in which

an angle between a plane and the sidewall is not smaller than a maximum incident angle of light incident on the sidewall, the plane connecting a side of a face of the light absorber that is on the opposite side from a light incident surface of the light absorber and is located on a side of the second pixel, to a side of the sidewall that is on the opposite side from a light incident surface of the metallic filter.

The semiconductor device according to any one of (1) to (7), in which

the reflected light reduction unit includes a light absorber that covers at least part of the sidewall.

The semiconductor device according to (8), in which

the light absorber is a black filter.

The semiconductor device according to (8), in which

the light absorber is an optical filter in which a red filter and a blue filter are stacked.

The semiconductor device according to any one of (1) to (7), in which

the reflected light reduction unit includes a low-reflection film that has a lower reflectance than a metal forming the metallic filter and covers at least part of the sidewall.

The semiconductor device according to any one of (1) to (7), in which

the reflected light reduction unit includes the sidewall that is inclined so as to move away from the boundary portion in a direction of the first pixel as a distance from a light incident surface of the metallic filter increases.

The semiconductor device according to (12), in which

an inclination angle of the sidewall with respect to the light incident surface of the metallic filter is not greater than (90°−the maximum incident angle of light incident on the sidewall).

an antireflective film that surrounds at least part of a periphery of the first pixel and reduces reflected light is formed on a light incident surface of the metallic filter.

The semiconductor device according to (14), in which

the antireflective film is a black filter.

The semiconductor device according to any one of (1) to (15), in which

the metallic filter is a plasmon filter.

the metallic filter is a Fabry-Perot.

An electronic apparatus including:

a semiconductor device; and

a signal processing unit that processes a signal output from the semiconductor device,

in which the semiconductor device includes:

a pixel unit in which a first pixel including a metallic filter and a second pixel not including the metallic filter are disposed adjacent to each other; and

a reflected light reduction unit that reduces reflected light on a sidewall of the metallic filter at a boundary portion between the first pixel and the second pixel.

Note that the advantageous effects described in this specification are merely examples, and the advantageous effects of the present technology are not limited to them and may include other effects.

REFERENCE SIGNS LIST