JP2020109779A - Imaging element and imaging apparatus - Google Patents

Abstract

To provide an imaging element capable of suppressing deterioration of quality.SOLUTION: The imaging element includes: a first microlens; a first photoelectric conversion unit for photoelectrically converting light transmitted through the first microlens to generate electric charges; a first electrode for outputting the electric charges generated by the first photoelectric conversion unit; a first absorption unit, provided between the first microlens and the first electrode, for absorbing a part of the light that has passed through the first microlens; a second microlens; a second photoelectric conversion unit for photoelectrically converting light transmitted through the second microlens to generate electric charges; a second electrode for outputting the electric charges generated by the second photoelectric conversion unit; and a second absorption unit, provided between the second microlens and the second electrode, for absorbing a part of the light transmitted through the second microlens.SELECTED DRAWING: Figure 3

Description

The present invention relates to an image pickup device and an image pickup apparatus.

An imaging device in which a light shielding layer made of a metal material is formed is known (Patent Document 1). Conventionally, improvement of focus detection accuracy has been required.

JP, 2016-51746, A

According to a first aspect of the invention, an imaging device includes a first microlens, a first photoelectric conversion unit that photoelectrically converts light that has passed through the first microlens, and generates an electric charge. Of the light transmitted through the first microlens, the first microlens being provided between the first electrode for outputting the electric charge generated by the photoelectric conversion unit and the first microlens. A first absorption part that absorbs light, a second microlens, a second photoelectric conversion part that photoelectrically converts light that has passed through the second microlens to generate charges, and the second photoelectric conversion part. A part of light transmitted through the second microlens is provided between the second microlens and the second electrode for outputting the electric charge generated in the conversion unit. A second absorbing portion that absorbs.
According to a second aspect of the invention, an image pickup apparatus includes the image pickup element according to the first aspect, and a detection unit that performs focus detection of an optical system based on the first signal and the second signal.

It is a figure which shows the structural example of the imaging device which concerns on 1st Embodiment. It is a figure which shows the example of arrangement|positioning of the pixel of the image sensor which concerns on 1st Embodiment. It is a figure which shows the structural example of the pixel of the image sensor which concerns on 1st Embodiment. FIG. 11 is a diagram showing a configuration example of pixels of an image sensor according to Modification 1. FIG. 11 is a diagram showing a configuration example of pixels of an image sensor according to Modification 2. FIG. 11 is a diagram for explaining characteristics of AF pixels of the image sensor according to Modification 2. FIG. 11 is a diagram showing a configuration example of pixels of an image sensor according to Modification 2. FIG. 11 is a diagram showing a configuration example of pixels of an image sensor according to Modification 2.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration example of a camera 1 which is an example of the image pickup apparatus according to the first embodiment. The camera 1 includes a camera body 2 and an interchangeable lens 3 that is an accessory that can be attached to the camera body 2. The interchangeable lens 3 is detachably attached to the camera body 2 by a mount portion (not shown). When the interchangeable lens 3 is attached to the camera body 2, the terminals provided on the body side connecting portion 202 and the terminals provided on the lens side connecting portion 302 are electrically connected. This enables power supply from the camera body 2 to the interchangeable lens 3 and communication between the camera body 2 and the interchangeable lens 3.

Light from the subject is incident in the Z-axis plus direction in FIG. Further, as shown in the coordinate axes of FIG. 1, the front side of the paper orthogonal to the Z-axis is the X-axis positive direction, and the downward direction of the paper orthogonal to the Z-axis and the X-axis is the Y-axis positive direction. In the following figures, the coordinate axes may be displayed so that the orientation of each figure can be understood with reference to the coordinate axes of FIG.

The interchangeable lens 3 includes a photographing optical system (imaging optical system) 31, a lens controller 32, and a lens memory 33. The photographing optical system 31 includes a plurality of lenses including a focus lens (focus adjustment lens) and a diaphragm, and forms a subject image on the image pickup surface 22a of the image pickup device 22 of the camera body 2. The image pickup surface 22a of the image pickup element 22 is, for example, a surface on which a photoelectric conversion unit described later is arranged or a surface on which microlenses are arranged.

The lens control unit 32 includes a processor such as a CPU, FPGA, and ASIC, and a memory such as ROM and RAM, and controls each unit of the interchangeable lens 3 based on a control program. When a signal indicating the movement direction or movement amount of the focus lens is input from the body control unit 21, the lens control unit 32 moves the focus lens forward and backward in the direction of the optical axis L1 based on the signal, and the photographing optical system 31. Adjust the focus position of. The lens controller 32 also controls the aperture diameter of the diaphragm based on the signal output from the body controller 21.

The lens memory 33 is composed of a non-volatile storage medium or the like. Information related to the interchangeable lens 3 is stored in the lens memory 33. The lens memory 33 stores data relating to the infinity position and the closest position of the focus lens, data relating to the shortest focal length and the longest focal length of the interchangeable lens 3, data relating to the F value (aperture value of the diaphragm), and the like. Writing of data to the lens memory 33 and reading of data from the lens memory 33 are controlled by the lens controller 32.

Next, the configuration of the camera body 2 will be described. The camera body 2 includes a body control unit 21, an image pickup element 22, a memory 23, a display unit 24, and an operation unit 25. The image sensor 22 is a CMOS image sensor or a CCD image sensor. The image pickup device 22 picks up a subject image formed by the photographing optical system 31. In the image sensor 22, a plurality of pixels each having a photoelectric conversion unit are two-dimensionally arranged (row direction and column direction). The image sensor 22 photoelectrically converts the received light by a photoelectric conversion unit to generate a signal, and outputs the generated signal to the body control unit 21.

As will be described later, the image pickup device 22 has image pickup pixels that output signals used for image generation and AF pixels (focus detection pixels) that output signals used for focus detection. The imaging pixels are arranged according to the Bayer array. The AF pixels are arranged by being replaced with a part of the image pickup pixels, and are arranged dispersedly over almost the entire image pickup surface 22a of the image pickup device 22.

The memory 23 is composed of a non-volatile storage medium or the like. Image data, control programs, and the like are recorded in the memory 23. The writing of data to the memory 23 and the reading of data from the memory 23 are controlled by the body control unit 21. The display unit 24 displays an image based on image data, an image showing a focus detection area (AF area) such as an AF frame, information regarding shooting such as shutter speed and F value, and a menu screen. The operation unit 25 includes a release button, a power switch, various setting switches such as a switch for switching various modes, and the like, and outputs a signal based on each operation to the body control unit 21.

The body control unit 21 includes a processor such as a CPU, FPGA, and ASIC, and a memory such as ROM and RAM, and controls each unit of the camera 1 based on a control program. The body control unit 21 has an image data generation unit 21a and a focus detection unit 21b. The image data generation unit 21a performs various kinds of image processing on the signals output from the image pickup pixels of the image pickup element 22 to generate image data. The image data generation unit 21a may also generate image data using signals output from the AF pixels of the image sensor 22. The image processing includes image processing such as gradation conversion processing and color interpolation processing.

The focus detection unit 21b performs focus detection processing required for automatic focus adjustment (AF) of the photographing optical system 31. The focus detection unit 21b determines the focus position of the focus lens (the amount of movement of the focus lens to the focus position) for focusing (imaging) the image by the photographing optical system 31 on the imaging surface 22a of the image sensor 22. To detect. The focus detection unit 21b calculates the defocus amount by the phase difference detection method using the first and second signals output from the pair of AF pixels (AF pixel pair) of the image sensor 22.

The focus detection unit 21b captures an image of the first light flux that has passed through the first pupil area of the exit pupil of the imaging optical system 31 and generates a signal, and an image of the second light flux that has passed through the second pupil area. The image shift amount is calculated by performing a correlation calculation with the signal generated by capturing the image. The focus detection unit 21b converts this image shift amount into a defocus amount based on a predetermined conversion formula. The focus detection unit 21b calculates the amount of movement of the focus lens to the in-focus position based on the calculated defocus amount.

The focus detection unit 21b determines whether the defocus amount is within the allowable value. The focus detection unit 21b determines that the subject is in focus if the defocus amount is within the allowable value. On the other hand, when the defocus amount exceeds the permissible value, the focus detection unit 21b determines that the focus is not achieved, and a signal that instructs the lens control unit 32 of the interchangeable lens 3 to move the focus lens and to move the lens. To send. The lens controller 32 moves the focus lens according to the amount of movement, whereby focus adjustment is automatically performed.
The configuration of the image sensor 22 according to this embodiment will be described below. Particularly, the function of the absorbing portion 43 will be described with reference to FIGS.

The outline of the image pickup device 22 is as follows.
Referring to FIG. 2, the image sensor 22 has a plurality of first pixels 11 and a plurality of second pixels 13. The first pixel 11 and the second pixel 13 are AF pixels. The first pixel 11 and the second pixel 13 are paired to generate a signal indicating the focus adjustment state.
Referring to FIG. 3, the first pixel 11 includes a first microlens 44 on which the first light 61 and the second light 62 transmitted through the optical system enter, and a first microlens 44 that photoelectrically converts the light to generate charges. It has one photoelectric conversion unit 42 and a first absorption unit 43 arranged between the first microlens 44 and the first photoelectric conversion unit 42. The first absorber 43 absorbs part of the second light 62 that has passed through the first microlens 44. The second pixel 13 includes a second microlens 44 on which the first light 61 and the second light 62 that have passed through the optical system are incident, and a second photoelectric conversion unit 42 that photoelectrically converts the light to generate an electric charge. And a second absorption part 43 between the second microlens 41 and the second photoelectric conversion part 42. The second absorber 43 absorbs part of the first light 61 that has passed through the second microlens 41.

FIG. 2 is a diagram showing an arrangement example of pixels of the image sensor 22 according to the first embodiment. In the image sensor 22, pixels are arranged two-dimensionally (row direction (±X direction) and column direction (±Y direction)). The example shown in FIG. 2 illustrates a total of 64 pixels in 8 rows and 8 columns. Note that the number and arrangement of pixels arranged in the image sensor 22 are not limited to the illustrated example.

The image pickup element 22 has a plurality of image pickup pixels 12 and AF pixels 11 and 13. The imaging pixel 12 is provided with any one of three color filters (color filters) 51 having different spectral characteristics of red (R), green (G), and blue (B). A pixel (hereinafter, referred to as an R pixel) having a color filter 51 having a spectral characteristic that disperses light in a first wavelength region (red (R) light) of the incident light into the imaging pixel 12, Of the incident light, a pixel (hereinafter, referred to as a G pixel) having a color filter 51 having a spectral characteristic that disperses the light in the second wavelength range (green (G) light) and the third of the incident light A pixel (hereinafter, referred to as a B pixel) having a color filter 51 having a spectral characteristic for dispersing light in a wavelength range (blue (B) light) is included. The R pixel 12r, the G pixel 12g, and the B pixel 12b are arranged according to the Bayer array.

The AF pixels 11 and 13 are arranged by replacing a part of the R, G, and B imaging pixels 12 arranged in the Bayer array as described above. In the AF pixel 11 and the AF pixel 13, a color filter 51 having a spectral characteristic that disperses the light (green (G) light) in the second wavelength region of the incident light is arranged. The color filters included in each of the AF pixel 11 and the AF pixel 13 disperse light in the first wavelength range (light of red (R)) or light in the third wavelength range (light of blue (B)). It may be a color filter having a spectral characteristic of Further, the AF pixel 11 and the AF pixel 13 may have a filter having a spectral characteristic that disperses light in the first, second, and third wavelength regions of the incident light. Alternatively, the color filter 51 may not be arranged in the AF pixel 11 and the AF pixel 13.

The AF pixels 11 and 13 according to the present embodiment are provided with an absorber 43 that absorbs incident light. The position of the absorbing portion 43 is different between the AF pixel 11 and the AF pixel 13. The absorber 43 of each of the AF pixel 11 and the AF pixel 13 is arranged such that light passing through different regions of the exit pupil of the photographing optical system 31 enters the photoelectric conversion unit 42. As will be described later, the absorber 43 of each of the AF pixels 11 and 13 absorbs part of the light 61 and 62 that has passed through different regions of the exit pupil of the photographing optical system 31. The photoelectric conversion section 42 of each of the AF pixels 11 and 13 photoelectrically converts the light that has not been absorbed by the absorption section 43 among the light that has passed through the microlens 44 and the color filter 51.

As shown in FIG. 2, the image sensor 22 includes a first pixel group 401 in which R pixels 12r and G pixels 12g are alternately arranged in ±X directions, that is, row directions, a G pixel 12g and a B pixel 12b. And second pixel groups 402 arranged alternately in the row direction. The image sensor 22 also has a third pixel group 403 in which the G pixels 12g and the AF pixels 11 and 13 are arranged in the row direction. In the example shown in FIG. 2, the AF pixel 11 and the AF pixel 13 are alternately arranged with the G pixel 12g interposed therebetween.

The third pixel group 403 may not have both the AF pixels 11 and 13. The second pixel group 402 may include the G pixel 12g and the AF pixel 11, and the third pixel group 403 may include the G pixel 12g and the AF pixel 13. Further, the third pixel group 403 has AF pixels 11 and 13 in a plurality of columns in which the B pixels 12b of the second pixel group 402 are arranged, but the B pixel 12b of the second pixel group 402 is The AF pixels 11 and 13 may be provided in a part of the plurality of columns in which are arranged. Either one of the two pixels 11 in FIG. 3 or one of the two pixels 13 may be omitted. The third pixel group 403 may include at least one of the AF pixels 11 and 13, the G pixel 12g, and the B pixel 12b.

FIG. 3 is a diagram showing a configuration example of image pickup pixels and AF pixels of the image pickup device 22 according to the first embodiment. FIG. 3 shows one image pickup pixel 12, one AF pixel 11, and one AF pixel 13 among the pixels provided in the image pickup device 22. As described above, the light that has passed through the photographing optical system 31 is incident on the image sensor 22 mainly in the Z-axis plus direction. A light beam that has passed through one of the first pupil regions, which is obtained by dividing the exit pupil of the photographing optical system 31 into approximately two equal parts, is indicated by a solid line arrow as a first light beam 61, and passes through the other second pupil region, which is substantially divided into two. The formed luminous flux is shown as a second luminous flux 62 by a dashed arrow.

The image sensor 22 includes a substrate 110 and a wiring layer 111 that is provided by being stacked on the substrate 110. The substrate 110 is composed of a semiconductor substrate such as silicon. The wiring layer 111 is a wiring layer including a conductor film (metal film) and an insulating film, and has a plurality of wires and vias arranged therein. Copper, aluminum, tungsten, etc. are used for the conductor film. The insulating film is composed of an oxide film, a nitride film, or the like.

Each of the AF pixel 11, the imaging pixel 12, and the AF pixel 13 has a microlens 44, a first flattening layer 81, a color filter 51, a second flattening layer 82, and a protective layer 83. The first electrode 45a, the photoelectric conversion unit 42, the second electrode 45b, and the storage unit 54 connected to the second electrode 45b via the wiring 53 are provided. The microlens 44 condenses the light incident from above via the photographing optical system 31 in FIG. In the example shown in FIG. 3, a G color filter 51 is arranged in each of the AF pixels 11 and 13 and the imaging pixel 12. FIG. 3 is a vertical cross-sectional view of the pixel group 403 of FIG. 2 taken along a cutting line extending in the ±X directions.

The first flattening layer (flattening film) 81 is made of an organic material such as resin, and is provided between the microlens 44 and the color filter 51. The second flattening layer (flattening film) 82 is made of an organic material such as resin, and is provided between the color filter 51 and the photoelectric conversion unit 42. Further, a part of the second flattening layer 82 is provided between the color filter 51 and the absorber 43, and another part of the second flattening layer 82 is formed in the absorber 43 and the first electrode. It is provided between 45a. The protective layer (protective film) 83 is made of, for example, an organic material, and is provided between the absorption section 43 and the photoelectric conversion section 42. The protective layer 83 protects the first electrode 45a and the photoelectric conversion section 42. Note that the absorber 43 may be provided on the second flattening layer 82 or below the second flattening layer 82 in the light incident direction. The absorber 43 may be provided on the protective layer 83 or below the protective layer 83. In addition, the absorber 43 may be provided in the protective layer 83. The absorber 43 may be the same member as the second flattening layer 82 and the protective layer 83.

The photoelectric conversion section 42 is composed of a photoelectric conversion film made of an organic material. The photoelectric conversion unit 42 converts incident light into electric charges. The first electrode 45a is a transparent electrode and is made of ITO (indium tin oxide), titanium oxide, zinc oxide, or the like. The second electrode 45b is made of a metal material such as aluminum or tungsten.

As shown in FIG. 3, the first electrode 45 a is an electrode common to the photoelectric conversion units 42 of the plurality of pixels and is arranged on one surface side of the photoelectric conversion unit 42. The second electrode 45b is arranged on the other surface side of the photoelectric conversion unit 42 for each pixel. In this way, the first electrode 45a and the second electrode 45b are arranged so as to sandwich the photoelectric conversion unit 42. The first electrode 45a is an electrode above the photoelectric conversion section 42, and the second electrode 45b is an electrode below the photoelectric conversion section 42. The second electrode 45b is electrically connected to the storage unit 54 via the wiring 53 provided in the wiring layer 111.

Each of the AF pixels 11 and 13 has an absorbing portion 43 that absorbs a part of the light flux that has transmitted (passed) through the microlens 44 and the color filter 51. The absorption section 43 is located between the color filter 51 and the photoelectric conversion section 42, and is provided above the first electrode 45 a of the photoelectric conversion section 42. In the present embodiment, the absorber 43 is provided in the second flattening layer 82. In the example shown in FIG. 3, the absorber 43 is provided in a partial region of the second flattening layer 82.

The absorbing section 43 is a filter (black filter) made of an organic material such as a pigment and having a characteristic of absorbing light in the visible wavelength range. Assuming that the extinction coefficient of the absorption section 43 with respect to incident light having a wavelength of 530 nm is k, k is about 0.15 to 0.20. The absorbing part 43 may be formed to have an extinction coefficient k of about 0.1 to 0.30.

The absorption section 43 of the AF pixel 11 is arranged corresponding to a substantially left half of the photoelectric conversion section 42 (on the −X direction side of the photoelectric conversion section 42). The absorption section 43 of the AF pixel 11 is at least one in a region on the −X direction side of the center of the photoelectric conversion section 42 of the AF pixel 11 in the plane (XY plane) that intersects the light incident direction (Z-axis direction). Parts are arranged. The area 46 of the AF pixel 11 is an area corresponding to a substantially right half of the photoelectric conversion section 42 (the +X direction side of the photoelectric conversion section 42). At least a part of the area 46 of the AF pixel 11 is located in the area on the +X direction side of the center of the photoelectric conversion unit 42 of the AF pixel 11 in the plane (XY plane) that intersects with the light incident direction (Z-axis direction). This is the area to be placed.

On the other hand, the absorption section 43 of the AF pixel 13 is arranged corresponding to a region on the almost right half of the photoelectric conversion section 42 (on the +X direction side of the photoelectric conversion section 42). The absorption section 43 of the AF pixel 13 is at least partly in a region on the +X direction side of the center of the photoelectric conversion section 42 of the AF pixel 13 in the plane (XY plane) that intersects the light incident direction (Z axis direction). Are placed. The area 46 of the AF pixel 13 is an area corresponding to a substantially left half area of the photoelectric conversion section 42 (on the −X direction side of the photoelectric conversion section 42 ). The area 46 of the AF pixel 13 is at least partly in the area on the −X direction side of the center of the photoelectric conversion unit 42 of the AF pixel 13 in the plane (XY plane) that intersects with the light incident direction (Z-axis direction). Is an area in which is arranged.

In the AF pixel 11, a part of the second light flux 62 of the light flux that has passed through the microlens 44 and the color filter 51 is absorbed by the absorber 43. Further, in the AF pixel 11, the first light flux 61 of the light flux that has passed through the microlens 44 and the color filter 51 passes through the region 46 and enters the photoelectric conversion unit 42. The area 46 of the AF pixel 11 acts as an opening that allows the first light flux 61 that has passed through the microlens 44 and the color filter 51 to enter the photoelectric conversion unit 42.

The photoelectric conversion unit 42 of the AF pixel 11 receives the first light flux 61 and photoelectrically converts the first light flux 61 to generate electric charges. It should be noted that part of the light that has passed through the absorber 43 also enters the photoelectric converter 42. The photoelectric conversion unit 42 of the AF pixel 11 photoelectrically converts a part of the light transmitted through the absorption unit 43 to generate an electric charge.

On the other hand, in the AF pixel 13, a part of the first light flux 61 of the light flux that has passed through the microlens 44 and the color filter 51 is blocked by the absorber 43. Further, in the AF pixel 13, the second light flux 62 of the light flux that has passed through the microlens 44 and the color filter 51 passes through the region 46 and enters the photoelectric conversion unit 42. The area 46 of the AF pixel 13 acts as an opening that allows the second light flux 62 that has passed through the microlens 44 and the color filter 51 to enter the photoelectric conversion unit 42.

The photoelectric conversion unit 42 of the AF pixel 13 receives the second light flux 62 and photoelectrically converts the second light flux 62 to generate electric charges. It should be noted that part of the light that has passed through the absorber 43 also enters the photoelectric converter 42. The photoelectric conversion unit 42 of the AF pixel 13 photoelectrically converts a part of the light transmitted through the absorption unit 43 to generate an electric charge.

In the image pickup pixel 12, the first and second light fluxes 61 and 62 that have respectively passed through the first and second pupil regions of the exit pupil of the photographing optical system 31 pass through the microlens 44 and the color filter 51, and the photoelectric conversion unit. It is incident on 42. The photoelectric conversion unit 42 of the imaging pixel 12 photoelectrically converts the first and second light fluxes 61 and 62 to generate electric charges.

The charges photoelectrically converted by the photoelectric conversion unit 42 of each pixel are transferred to the storage unit 54 via the wiring 53 by the first electrode 45a and the second electrode 45b of the pixel. The storage unit 54 stores (holds) the charges transferred to the storage unit 54. Each pixel has an amplification transistor (not shown), and outputs a signal based on the charges accumulated in the accumulation unit 54. The first electrode 45a and the second electrode 45b form part of an output unit that outputs a signal based on the charges generated by the photoelectric conversion unit 42.

The AF pixel 11 photoelectrically converts the first light flux 61 that has passed through the first pupil region and outputs a first signal Sig1 based on the accumulated charges. The AF pixel 13 photoelectrically converts the second light flux 62 that has passed through the second pupil area and outputs a second signal Sig2 based on the accumulated charges. The imaging pixel 12 photoelectrically converts the first light flux 61 and the second light flux 62 and outputs a signal based on the accumulated charges.

The signal output from each pixel is input to a signal processing unit (not shown) arranged on the substrate 110 and subjected to signal processing, and then output to the body control unit 21 of the camera 1. The signal processing unit includes an analog/digital conversion unit (AD conversion unit) that converts the signal output from the pixel into a digital signal.

Although the AF pixels 11 and 13 are arranged in the row direction (±X direction) in FIGS. 2 and 3, they may be arranged in the column direction (±Y direction). When the AF pixels 11 and 13 are arranged in the column direction, the absorber 43 of the AF pixel 11 is arranged so as to correspond to one of the upper half region and the lower half region of the photoelectric conversion unit 42. The absorption part 43 is arranged corresponding to the other region of the upper half and the lower half of the photoelectric conversion part 42. For example, at least a part of the absorption section 43 of the AF pixel 11 is arranged in a region on the +Y direction side of the center of the photoelectric conversion section 42 of the AF pixel 11. At least a part of the absorption section 43 of the AF pixel 13 is arranged in a region on the −Y direction side of the center of the photoelectric conversion section 42 of the AF pixel 13.

As described above, in the AF pixel 11 and the AF pixel 13, the absorbing portions 43 are provided at positions different from each other in the direction intersecting the light incident direction. The absorber 43 of the AF pixel 11 absorbs a part of the second light flux 62, and the absorber 43 of the AF pixel 13 absorbs a part of the first light flux 61. As a result, the photoelectric conversion unit 42 of the AF pixel 11 mainly receives the first light flux 61, and the photoelectric conversion unit 42 of the AF pixel 13 mainly receives the second light flux 62. The first signal Sig1 output from the AF pixel 11 has many signal components due to the light passing through the first pupil region, and the second signal Sig2 output from the AF pixel 13 passes through the second pupil region. There are many signal components due to the light. Therefore, by using the first signal Sig1 output from the AF pixel 11 and the second signal Sig2 output from the AF pixel 13, information on the phase difference of the subject image can be obtained and the defocus amount can be reduced. It can be calculated.

Further, in the present embodiment, the absorber 43 is made of a material that absorbs visible light with almost no reflection. Therefore, stray light due to reflection can be reduced, and it is possible to avoid affecting the signals generated in each pixel. Further, a part of the second flattening layer (flattening film) 82 is arranged between the absorber 43 and the first electrode 45a. As a result, the flatness of the absorber 43 can be improved, and variations in the characteristics of the absorber 43 of each pixel can be suppressed. Note that the absorber 43 may be arranged on the first electrode 45 a of the photoelectric conversion unit 42 without providing the second planarization layer 82.

When a light-shielding film (metal light-shielding film) made of a metal material for detecting a phase difference is formed on an image sensor in which a photoelectric conversion film made of an organic material is arranged, the metal light-shielding film is formed in a predetermined pattern. Therefore, the other layers (films) such as the photoelectric conversion film and the transparent electrode may be damaged. In this case, it is conceivable that the characteristics of the photoelectric conversion film and the transparent electrode are deteriorated, the dark current is increased, and the quality of the signal of the pixel is deteriorated to deteriorate the focus detection accuracy. Further, when the metal light-shielding film is arranged immediately above the photoelectric conversion film, load capacitance (parasitic capacitance) is provided between the metal light-shielding film and the photoelectric conversion film, or between the metal light-shielding film and the signal line for controlling the pixel. May occur, the pixel cannot be driven at high speed, and the image sensor 22 may not operate at high speed.

In addition, it is generally difficult to form a metal film in an organic film, and it is difficult to arrange a metal light-shielding film in a flattening film made of an organic material. Therefore, when the metal light-shielding film is arranged, a step difference may occur between pixels, which may cause variations in the characteristics of each pixel. In the first place, it is conceivable that the metal light-shielding film cannot be formed on the photoelectric conversion film made of an organic material.

On the other hand, in the present embodiment, the image sensor 22 is provided with a light shielding film made of an organic material. When forming a light-shielding film made of an organic material, it is not necessary to use an etching solution for a metal light-shielding film, and a light-shielding film made of an organic material is formed into a pattern by using a developing solution for a photoresist (for example, a negative resist). It is formed. Therefore, it is possible to suppress damage to other layers and prevent deterioration of pixel characteristics. Further, it is possible to prevent the occurrence of the load capacity as described above, and it is possible to avoid the decrease in the processing speed.

Next, an operation example of the camera 1 according to the present embodiment will be described. When the power switch of the operation unit 25 is operated, the camera 1 sequentially outputs the first signal Sig1 of the AF pixel 11, the second signal Sig2 of the AF pixel 13, and the signal of the imaging pixel 12 from the imaging element 22. To be done. The focus detection unit 21b of the body control unit 21 calculates the defocus amount by the phase difference detection method using the first signal Sig1 and the second signal Sig output from the AF pixels 11 and 13 of the image sensor 22. .. The lens control unit 32 moves the focus lens of the photographing optical system 31 to the in-focus position and adjusts the focus based on the defocus amount calculated by the focus detection unit 21b. Instead of moving the focus lens, the image pickup device 22 may be moved in the optical axis L1 direction of the photographing optical system 31.

The image data generation unit 21a of the body control unit 21 generates image data based on the signal output from the image pickup pixel 12 of the image pickup device 22. The image data generation unit 21a generates image data for a through image (live view image) of a subject and image data for recording. The display unit 24 displays an image based on the image data for the through image. The image data for recording is recorded in the memory 23.

According to the above-mentioned embodiment, the following effects can be obtained.
(1) The image sensor 22 includes a first microlens 44 on which the first light 61 and the second light 61 that have passed through the optical system are incident, and a first photoelectric conversion that photoelectrically converts the light to generate an electric charge. The first absorption unit 43 that is provided between the unit 42 and the first microlens 44 and the first photoelectric conversion unit 42 and that absorbs a part of the second light 62 that has passed through the first microlens 44. And a second microlens 44 on which the first light 61 and the second light 62 are incident, a second photoelectric conversion unit 42 that photoelectrically converts the light to generate an electric charge, A second absorption part 43 which is provided between the second microlens 44 and the second photoelectric conversion part 42, and which absorbs a part of the first light 61 transmitted through the second microlens 44. Two pixels 13 are provided. In the present embodiment, the image sensor 22 includes the AF pixel 11 having the absorbing portion 43 that absorbs a part of the second light flux 62 and the AF pixel 11 that has the absorbing portion 43 that absorbs a part of the first light flux 61. Pixels 13 are arranged. Therefore, by using the signals output from the AF pixel 11 and the AF pixel 13, it is possible to obtain information on the phase difference of the subject image. The image shift amount can be calculated using the signals output from the AF pixel 11 and the AF pixel 13, and the defocus amount can be calculated.

(2) The imaging device 1 includes the imaging element 22 and a detection unit (focus detection unit 21b) that performs focus detection of the optical system based on the first signal Sig1 and the second signal Sig2. In the present embodiment, the image sensor 22 outputs a first signal Sig1 based on the electric charges obtained by photoelectrically converting the first light flux 61 and a second signal Sig2 based on the electric charges obtained by photoelectrically converting the second light flux 62. Output to the body control unit 21. Therefore, the focus detection unit 21b of the body control unit 21 can calculate the defocus amount using the first signal Sig1 and the second signal Sig2. The camera 1 can perform focus adjustment based on the defocus amount calculated by the focus detection unit 21b.

The following modifications are also within the scope of the present invention, and one or more modifications can be combined with the above-described embodiment.

(Modification 1)
FIG. 4 is a diagram illustrating a configuration example of pixels of the image sensor according to the first modification. The image sensor 22 according to the present modified example has an absorbing section 47 provided between adjacent pixels. In the example shown in FIG. 4, the absorbing section 47 is provided in the second flattening layer 82 and at the boundary between adjacent pixels. In the camera 1, abnormal light (ghost light) is generated due to reflection of light that has passed through the photographing optical system 31 in the housing of the camera body 2, the microlens 44 of the image pickup element 22, and the like, and Light having a large incident angle may enter the microlens 44.

In the present modification, a part of the ghost light that has passed through the microlens 44 and the color filter 51 enters the absorbing section 47 and is absorbed by the absorbing section 47. As a result, light leaking from a pixel to the photoelectric conversion unit 42 of the pixel adjacent to the pixel can be reduced. Therefore, it is possible to suppress the signal component generated by the pixel from being mixed with the signal component due to the light leaked from the adjacent pixel. It is possible to prevent the accuracy of the defocus amount calculated using the signals output from the AF pixels 11 and 13 from decreasing and the quality of an image generated using the signals output from the imaging pixels 12 to decrease. be able to. Note that the above description applies to the influence of various incident lights having large incident angles.

(Modification 2)
The absorbing part may be formed so that the upper part and the lower part of the absorbing part have different widths. FIG. 5 is a diagram illustrating a configuration example of pixels of an image sensor according to the second modification. As shown in FIG. 5, the width of the absorbing portion 43 may be made smaller as it goes upward (to the −Z direction side). When the width of the upper portion of the absorbing portion 43 is Wt1 and the width of the lower portion of the absorbing portion 43 is Wb1, the absorbing portion 43 is formed so that Wb1>Wt1. In this case, the inclined surface 48 is formed on the edge portion of the absorbing portion 43. The area of the upper portion of the absorbing portion 43 is smaller than the area of the lower portion of the absorbing portion 43.

The transmittance of the absorber 43 changes depending on the shape of the absorber 43, and the amount of light received by the photoelectric converter 42 changes. Therefore, the incident angle of the light incident on the AF pixel and the output from the AF pixel are different when the absorbing section 43 does not have the inclined surface 48 (FIG. 3) and when the absorbing section 43 has the inclined surface 48 (FIG. 5). The relationship between the signal being processed and the signal level changes.

FIG. 6 is a diagram showing the relationship between the incident angle and the output signal of the AF pixel. In FIG. 6, the vertical axis represents the signal level of the signal output from the AF pixel, and the horizontal axis represents the incident angle of light incident on the AF pixel. The waveform 61a shows the signal level of the output signal of the AF pixel 11 when there is no inclined surface 48, and the waveform 61b shows the signal level of the output signal of the AF pixel 11 when there is inclined surface 48. Further, the waveform 62 a shows the signal level of the output signal of the AF pixel 13 when the inclined surface 48 is not provided, and the waveform 62 b shows the signal level of the output signal of the AF pixel 13 when the inclined surface 48 is provided. These waveforms represent the performance of pupil division by AF pixels, and are parameters that affect the AF performance.

Comparing the waveforms (61a, 62a) without the inclined surface 48 and the waveforms (61b, 62b) with the inclined surface 48, the inclination of the waveform becomes gentler when the inclined surface 48 is present. When the inclined surface 48 is provided, the incident light is gradually absorbed by the absorbing portion 43 as the incident angle becomes smaller (closer to 0), and therefore the inclination of the waveforms (61b, 62b) becomes gentle. In this way, by providing the inclined surface 48 at the end of the absorption section 43, the pupil division characteristic of the AF pixel can be changed.

The cross-sectional shape of the end portion of the absorbing portion 43 does not change linearly, but may be a curve or the like as shown in FIGS. Further, as shown in FIG. 8, the width of the absorbing portion 43 may be increased as it goes upward (to the −Z direction side). When the width of the upper portion of the absorbing portion 43 is Wt2 and the width of the lower portion of the absorbing portion 43 is Wb2, the absorbing portion 43 is formed so that Wb2<Wt2. The area of the upper part of the absorber 43 is larger than the area of the lower part of the absorber 43. In this way, by adjusting the shape of the absorber 43, the pupil division characteristic of the AF pixel can be adjusted. In addition, a plurality of types of AF pixel pairs (AF pixel 11 and AF pixel 13) in which the inclination of the inclined surface 48 is different from each other may be arranged. In this case, the camera 1 may select an AF pixel pair used for focus detection from a plurality of types of AF pixel pairs.

(Modification 3)
In general, the light passing through the exit pupil of the photographing optical system 31 is incident on the center of the image pickup surface 22a of the image pickup device 22 almost vertically, whereas the peripheral portion located outside the center, that is, the image pickup surface 22a. Light is obliquely incident on a region away from the center of the. Therefore, the area and the position of the absorber 43 of each pixel may be different depending on the position (for example, image height) of the pixel in the image sensor 22. Further, the position of the exit pupil and the exit pupil distance of the photographing optical system 31 are different between the central portion and the peripheral portion of the image pickup surface 22a of the image pickup element 22. Therefore, the area or position of the absorbing portion 43 of each pixel may be different depending on the position of the exit pupil or the exit pupil distance. As a result, it is possible to increase the amount of light that enters the photoelectric conversion unit via the imaging optical system 31 and to appropriately perform pupil division in that state even when light is obliquely incident.

(Modification 4)
In the embodiment described above, the example in which the photoelectric conversion film is used as the photoelectric conversion unit has been described. However, the photoelectric conversion section 42 may be configured by a photoelectric conversion film made of an inorganic material. A photodiode may be used as the photoelectric conversion unit.

(Modification 5)
In the above-described embodiment, the case where the primary color system (RGB) color filter is used for the image sensor 22 has been described, but a complementary color system (CMY) color filter may be used.

(Modification 6)
The image pickup device and the image pickup apparatus described in the above-described embodiments and modifications are applied to a camera, a smartphone, a tablet, a camera built in a PC, an in-vehicle camera, a camera mounted in an unmanned aerial vehicle (drone, radio controlled machine, etc.), and the like. May be done.
Moreover, you may use the above-mentioned absorption part as a filter (bandpass filter) which blocks visible light and permeate|transmits infrared light. In this case, since the photoelectric conversion unit efficiently receives infrared light and focus detection using infrared light is possible, the present invention is applied to a camera (for example, an in-vehicle camera or medical device) in which an image by infrared light is used. Camera).

Although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other modes that are conceivable within the scope of the technical idea of the present invention are also included within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1... Imaging device, 2... Camera body, 3... Interchangeable lens, 21... Body control part, 21a... Image data generation part, 21b... Focus detection part, 22... Imaging element, 31... Photographing optical system, 42... Photoelectric conversion part , 44... Microlens, 43... Absorption part, 45a... First electrode, 45b... Second electrode, 51... Color filter, 81... First flattening layer, 82... Second flattening layer, 110... substrate

Claims (15)

To output a first microlens, a first photoelectric conversion unit that photoelectrically converts light that has passed through the first microlens to generate an electric charge, and an electric charge generated by the first photoelectric conversion unit A first electrode, and a first absorption part provided between the first microlens and the first electrode, for absorbing a part of light transmitted through the first microlens,
To output a second microlens, a second photoelectric conversion unit that photoelectrically converts light that has passed through the second microlens to generate an electric charge, and an electric charge generated by the second photoelectric conversion unit A second electrode, and a second absorbing portion that is provided between the second microlens and the second electrode, and that absorbs a part of the light that has passed through the second microlens,
An image pickup device including. The image sensor according to claim 1,
The first absorption unit absorbs a part of the second light of the first light and the second light transmitted through the first microlens,
The said 2nd absorption part is an image sensor which absorbs a part of said 1st light among the said 1st light and said 2nd light which permeate|transmitted the said 2nd micro lens. The image sensor according to claim 2,
The first microlens and the second microlens include the first light transmitted through the first region of the optical system and the second light transmitted through the second region different from the first region of the optical system. An image sensor that transmits the light of 2. The image sensor according to claim 2 or 3,
The first photoelectric conversion unit photoelectrically converts the first light that has passed through the first microlens and the light that has passed through the first microlens and the first absorption unit to generate an electric charge. Generate,
The second photoelectric conversion unit photoelectrically converts the second light that has passed through the second microlens and the light that has passed through the second microlens and the second absorption unit into electric charge. Image sensor to generate. The image sensor according to any one of claims 1 to 4,
In the direction intersecting the direction in which the light transmitted through the first microlens is incident, the length of the first absorption unit is closer to the first microlens side than the first photoelectric conversion unit side. Is short,
In the direction intersecting the direction in which the light transmitted through the second microlens is incident, the length of the second absorption unit is closer to the second microlens side than the second photoelectric conversion unit side. An image sensor with a short length. The image sensor according to any one of claims 1 to 4,
In the direction intersecting with the direction in which the light transmitted through the first microlens is incident, the area of the first absorption section is closer to the first microlens side than to the first photoelectric conversion section side. small,
In the direction intersecting the direction in which the light transmitted through the second microlens is incident, the area of the second absorption section is closer to the second microlens side than to the second photoelectric conversion section side. Small image sensor. The image sensor according to any one of claims 1 to 4,
In the direction intersecting the direction in which the light transmitted through the first microlens is incident, the length of the first absorption unit is closer to the first microlens side than the first photoelectric conversion unit side. Is long
In the direction intersecting the direction in which the light transmitted through the second microlens is incident, the length of the second absorption unit is closer to the second microlens side than the second photoelectric conversion unit side. Long image sensor. The image sensor according to any one of claims 1 to 4,
In the direction intersecting with the direction in which the light transmitted through the first microlens is incident, the area of the first absorption section is closer to the first microlens side than to the first photoelectric conversion section side. big,
In the direction intersecting the direction in which the light transmitted through the second microlens is incident, the area of the second absorption section is closer to the second microlens side than to the second photoelectric conversion section side. Large image sensor. The image sensor according to any one of claims 1 to 8,
An imaging device comprising a flattening layer or a protective layer provided between the first absorption section and the second absorption section and the first photoelectric conversion section and the second photoelectric conversion section. The image sensor according to any one of claims 1 to 9,
The image pickup device in which the first absorption section and the second absorption section are black filters. The image sensor according to any one of claims 1 to 10,
The first absorption section and the second absorption section are imaging elements made of an organic material. The image sensor according to any one of claims 1 to 11,
The first photoelectric conversion unit and the second photoelectric conversion unit are photoelectric conversion units made of an organic material. The image sensor according to any one of claims 1 to 12,
A third electrode for outputting the electric charge generated by the first photoelectric conversion unit;
A fourth electrode for outputting the electric charge generated by the second photoelectric conversion unit,
The first photoelectric conversion unit is provided between the first electrode and the third electrode,
The second photoelectric conversion unit is an image sensor provided between the second electrode and the fourth electrode. The image sensor according to any one of claims 1 to 13,
A first output unit that outputs a first signal used for focus detection based on the charges generated by the first photoelectric conversion unit;
A second output unit that outputs a second signal used for focus detection based on the charges generated by the second photoelectric conversion unit;
An image pickup device including. An image sensor according to claim 14;
A detection unit that performs focus detection of the optical system based on the first signal and the second signal;
An imaging device including.

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