JP7283078B2 - Imaging element and imaging device - Google Patents

Description

The present invention relates to an imaging device and an imaging device.

2. Description of the Related Art An imaging device having a light shielding layer made of a metal material is known (Patent Document 1). Conventionally, there has been a demand for improvement in focus detection accuracy.

JP 2016-51746 A

According to a first aspect of the invention, an imaging device includes: a first microlens; a first photoelectric conversion unit configured to photoelectrically convert light transmitted through the first microlens to generate an electric charge; A first electrode provided between the first microlens and the first electrode for outputting an electric charge generated in the photoelectric conversion portion of the first microlens and the first electrode transmitted through the first microlens a first absorption portion that absorbs part of the second light out of the light and the second light; a second microlens; , a second electrode for outputting the charge generated by the second photoelectric conversion unit, and provided between the second microlens and the second electrode and a second absorption part that absorbs part of the first light out of the first light and the second light transmitted through the second microlens.
According to a second aspect of the invention, an imaging device includes the imaging element according to the first aspect, and a detection section that performs focus detection of the optical system based on the first signal and the second signal.

1 is a diagram illustrating a configuration example of an imaging device according to a first embodiment; FIG. FIG. 2 is a diagram showing an arrangement example of pixels of an imaging device according to the first embodiment; 2A and 2B are diagrams illustrating configuration examples of pixels of an image sensor according to the first embodiment; FIG. FIG. 10 is a diagram showing a configuration example of pixels of an imaging device according to Modification 1; FIG. 10 is a diagram showing a configuration example of pixels of an imaging element according to modification 2; FIG. 11 is a diagram for explaining characteristics of AF pixels of an image sensor according to Modification 2; FIG. 10 is a diagram showing a configuration example of pixels of an imaging element according to modification 2; FIG. 10 is a diagram showing a configuration example of pixels of an imaging element according to modification 2;

(First embodiment)
FIG. 1 is a diagram showing a configuration example of a camera 1, which is an example of an imaging device according to the first embodiment. A camera 1 is composed of a camera body 2 and an interchangeable lens 3 as an accessory attachable to the camera body 2 . The interchangeable lens 3 is detachably attached to the camera body 2 by a mount section (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 a subject is incident in the positive direction of the Z axis in FIG. As shown in the coordinate axes of FIG. 1, the frontward direction perpendicular to the Z-axis is the positive X-axis direction, and the downward direction perpendicular to the Z-axis and the X-axis is the positive Y-axis direction. In the following figures, the coordinate axes may be displayed with reference to the coordinate axes of FIG. 1 so that the direction of each figure can be understood.

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

The lens control unit 32 includes a processor such as CPU, FPGA, and ASIC, and memory such as ROM and RAM, and controls each unit of the interchangeable lens 3 based on a control program. When the lens control unit 32 receives a signal indicating the direction and amount of movement of the focus lens from the body control unit 21, the lens control unit 32 advances and retreats the focus lens in the direction of the optical axis L1 based on the signal. adjust the focal position of the Also, the lens control unit 32 controls the aperture diameter of the diaphragm based on the signal output from the body control unit 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 regarding the infinity position and the closest position of the focus lens, data regarding the shortest and longest focal lengths of the interchangeable lens 3, data regarding the F-number (aperture value), and the like. Writing data to the lens memory 33 and reading 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 section 21 , an imaging device 22 , a memory 23 , a display section 24 and an operation section 25 . The imaging device 22 is a CMOS image sensor or a CCD image sensor. The imaging device 22 captures an object image formed by the imaging optical system 31 . In the imaging device 22, a plurality of pixels each having a photoelectric conversion unit are arranged two-dimensionally (row direction and column direction). The imaging element 22 photoelectrically converts the received light in the photoelectric conversion section to generate a signal, and outputs the generated signal to the body control section 21 .

The imaging element 22 has imaging pixels that output signals used for image generation and AF pixels (focus detection pixels) that output signals used for focus detection, as will be described later. The imaging pixels are arranged according to the Bayer array. The AF pixels are arranged to replace some of the imaging pixels, and are distributed over substantially the entire imaging surface 22 a of the imaging device 22 .

The memory 23 is configured by a nonvolatile storage medium or the like. Image data, control programs, and the like are recorded in the memory 23 . Writing data to the memory 23 and reading 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 indicating a focus detection area (AF area) such as an AF frame, information related to shooting such as shutter speed and F-number, a menu screen, and the like. The operation unit 25 includes various setting switches such as a release button, a power switch, and switches for switching various modes, and outputs signals based on respective operations to the body control unit 21 .

The body control unit 21 includes a processor such as CPU, FPGA, and ASIC, and memory such as ROM and RAM, and controls each unit of the camera 1 based on a control program. The body control section 21 has an image data generation section 21a and a focus detection section 21b. The image data generator 21a performs various image processing on the signals output from the imaging pixels of the imaging device 22 to generate image data. Note that the image data generator 21 a may also use signals output from AF pixels of the image sensor 22 to generate image data. Image processing includes image processing such as tone conversion processing and color interpolation processing.

The focus detection unit 21b performs focus detection processing necessary for automatic focus adjustment (AF) of the photographing optical system 31. FIG. The focus detection unit 21b detects the focus position (movement amount of the focus lens to the focus position) of the focus lens 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 uses first and second signals output from a pair of AF pixels (AF pixel pair) of the image sensor 22 to calculate a defocus amount by a phase difference detection method.

The focus detection unit 21b detects a signal generated by picking up an image of the first light flux that has passed through the first pupil region of the exit pupil of the photographing optical system 31 and an image of the second light flux that has passed through the second pupil region. and a signal generated by imaging to calculate the amount of image shift. 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 focus is achieved if the defocus amount is within the allowable value. On the other hand, when the defocus amount exceeds the allowable value, the focus detection unit 21b determines that the lens is out of focus, and sends a signal to the lens control unit 32 of the interchangeable lens 3 to instruct the movement amount of the focus lens and the lens movement. to send. Focus adjustment is automatically performed by the lens control unit 32 moving the focus lens according to the amount of movement.
The configuration of the imaging device 22 according to this embodiment will be described below. In particular, the function of the absorbing portion 43 will be described with reference to FIGS. 2 and 3. FIG.

The outline of the imaging device 22 is as follows.
Referring to FIG. 2 , the imaging device 22 has multiple first pixels 11 and multiple second pixels 13 . The first pixel 11 and the second pixel 13 are AF pixels. A pair of the first pixel 11 and the second pixel 13 generates 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 that have passed through the optical system are incident, and a first microlens 44 that photoelectrically converts the light to generate electric charges. 1 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 absorption portion 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 into 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 electric charges. and a second absorption portion 43 between the second microlens 41 and the second photoelectric conversion portion 42 . The second absorption portion 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 imaging element 22 according to the first embodiment. In the imaging device 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 of 8 rows and 8 columns. Note that the number and arrangement of pixels arranged in the imaging element 22 are not limited to the illustrated example.

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

The AF pixels 11 and 13 are arranged to replace some of the R, G, and B imaging pixels 12 arranged in the Bayer array as described above. The AF pixels 11 and 13 are provided with a color filter 51 having spectral characteristics for separating light in the second wavelength band (green (G) light) out of incident light. Note that the color filters included in each of the AF pixels 11 and 13 separate light in the first wavelength range (red (R) light) or light in the third wavelength range (blue (B) light). It may be a color filter having spectral characteristics that Further, the AF pixel 11 and the AF pixel 13 may have filters having spectral characteristics for separating light in the first, second, and third wavelength bands of incident light. Alternatively, the color filter 51 may not be arranged in the AF pixels 11 and 13 .

The AF pixels 11 and 13 according to the present embodiment are provided with absorption portions 43 that absorb incident light. The position of the absorbing portion 43 is different between the AF pixel 11 and the AF pixel 13 . The absorption units 43 of the AF pixels 11 and 13 are arranged so that light passing through different regions of the exit pupil of the imaging 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 lights 61 and 62 that have passed through different areas of the exit pupil of the imaging optical system 31 . The photoelectric conversion unit 42 of each of the AF pixels 11 and 13 photoelectrically converts the light that has passed through the microlens 44 and the color filter 51 and is not absorbed by the absorption unit 43 .

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 the ±X direction, that is, in the row direction, G pixels 12g and B pixels 12b. and a second pixel group 402 alternately arranged 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 pixels 11 and the AF pixels 13 are alternately arranged with the G pixel 12g interposed therebetween.

The third pixel group 403 does not have to have both AF pixels 11 and 13 . The second pixel group 402 may have the G pixel 12g and the AF pixel 11, and the third pixel group 403 may have the G pixel 12g and the AF pixel 13. Also, 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. may have AF pixels 11 and 13 in a part of a plurality of columns in which are arranged. Either one of the two pixels 11 or either one of the two pixels 13 in FIG. 3 may be omitted. The third pixel group 403 may have 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 imaging pixels and AF pixels of the imaging element 22 according to the first embodiment. FIG. 3 shows one imaging pixel 12 , one AF pixel 11 , and one AF pixel 13 among the pixels provided in the imaging element 22 . As described above, the light that has passed through the imaging optical system 31 enters the imaging device 22 mainly in the positive direction of the Z axis. A light flux that has passed through one of the first pupil regions obtained by dividing the exit pupil of the imaging optical system 31 into two halves is indicated by a solid line arrow as a first light luminous flux 61. The resulting light flux is indicated by a dashed arrow as a second light flux 62 .

The imaging device 22 includes a substrate 110 and a wiring layer 111 laminated 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, in which a plurality of wirings, vias, and the like are arranged. Copper, aluminum, tungsten, or the like is used for the conductor film. The insulating film is composed of an oxide film, a nitride film, or the like.

The AF pixel 11, the imaging pixel 12, and the AF pixel 13 each include a microlens 44, a first planarization layer 81, a color filter 51, a second planarization layer 82, a protective layer 83, A first electrode 45a, a photoelectric conversion section 42, a second electrode 45b, and a storage section 54 connected to the second electrode 45b through a wiring 53 are provided. The microlens 44 collects the light incident from above through the imaging optical system 31 in FIG. In the example shown in FIG. 3, G color filters 51 are arranged in the AF pixels 11 and 13 and the imaging pixel 12, respectively. 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 direction.

A first planarizing 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 . A second planarization layer (flatness film) 82 is made of an organic material such as resin, and is provided between the color filter 51 and the photoelectric conversion section 42 . A part of the second planarization layer 82 is provided between the color filter 51 and the absorption section 43, and another part of the second planarization layer 82 is provided between the absorption section 43 and the first electrode. 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 45 a and the photoelectric conversion section 42 . Note that the absorption section 43 may be provided above the second planarization layer 82 or may be provided below the second planarization layer 82 in the direction in which light is incident. The absorbing portion 43 may be provided on the protective layer 83 or may be provided below the protective layer 83 . Also, the absorbing portion 43 may be provided within the protective layer 83 . The absorbing portion 43 may be the same member as the second planarizing layer 82 and the protective layer 83 .

The photoelectric conversion part 42 is configured by a photoelectric conversion film made of an organic material. The photoelectric conversion unit 42 converts incident light into electric charge. 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.

The first electrode 45a is an electrode common to the photoelectric conversion units 42 of a plurality of pixels, and is arranged on one surface side of the photoelectric conversion units 42, as shown in FIG. The second electrode 45b is arranged on the other surface side of the photoelectric conversion section 42 for each pixel. Thus, the first electrode 45a and the second electrode 45b are arranged with the photoelectric conversion section 42 interposed therebetween. The first electrode 45 a is an upper electrode of the photoelectric conversion section 42 , and the second electrode 45 b is a lower electrode of the photoelectric conversion section 42 . The second electrode 45 b is electrically connected to the storage section 54 via the wiring 53 provided in the wiring layer 111 .

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

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

The absorbing portion 43 of the AF pixel 11 is arranged corresponding to the substantially left half region of the photoelectric conversion portion 42 (the −X direction side of the photoelectric conversion portion 42). At least one absorber 43 of the AF pixel 11 is located in a region on the −X direction side of the center of the photoelectric conversion unit 42 of the AF pixel 11 in a plane (XY plane) intersecting the direction of light incidence (Z-axis direction). part is placed. A region 46 of the AF pixel 11 is a region corresponding to approximately the right half region of the photoelectric conversion unit 42 (the +X direction side of the photoelectric conversion unit 42). At least part of the region 46 of the AF pixel 11 is located on the +X direction side of the center of the photoelectric conversion unit 42 of the AF pixel 11 on the plane (XY plane) intersecting the direction of incidence of light (Z-axis direction). This is the area to be placed.

On the other hand, the absorbing portion 43 of the AF pixel 13 is arranged corresponding to the region of approximately the right half of the photoelectric conversion portion 42 (the +X direction side of the photoelectric conversion portion 42). At least a part of the absorbing portion 43 of the AF pixel 13 is located in a region on the +X direction side of the center of the photoelectric conversion portion 42 of the AF pixel 13 in a plane (XY plane) intersecting the direction of incidence of light (Z-axis direction). is placed. A region 46 of the AF pixel 13 is a region corresponding to approximately the left half region of the photoelectric conversion unit 42 (the −X direction side of the photoelectric conversion unit 42). The region 46 of the AF pixel 13 is at least partly located in the region on the −X direction side of the center of the photoelectric conversion unit 42 of the AF pixel 13 in the plane (XY plane) intersecting the light incident direction (Z-axis direction). is placed.

In the AF pixel 11 , part of the second light beam 62 out of the light beams that have passed through the microlens 44 and the color filter 51 is absorbed by the absorbing portion 43 . In the AF pixel 11 , the first light beam 61 out of the light beams that have passed through the microlens 44 and the color filter 51 passes through the region 46 and enters the photoelectric conversion section 42 . The region 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 section 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. Part of the light that has passed through the absorption portion 43 also enters the photoelectric conversion portion 42 . The photoelectric conversion unit 42 of the AF pixel 11 photoelectrically converts part of the light transmitted through the absorption unit 43 to generate electric charge.

On the other hand, in the AF pixel 13 , part of the first light beam 61 out of the light beams transmitted through the microlens 44 and the color filter 51 is blocked by the absorbing portion 43 . In the AF pixel 13 , the second light beam 62 out of the light beams that have passed through the microlens 44 and the color filter 51 passes through the region 46 and enters the photoelectric conversion section 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 section 42 .

The photoelectric conversion unit 42 of the AF pixel 13 receives the second luminous flux 62 and photoelectrically converts the second luminous flux 62 to generate an electric charge. Part of the light that has passed through the absorption portion 43 also enters the photoelectric conversion portion 42 . The photoelectric conversion unit 42 of the AF pixel 13 photoelectrically converts part of the light transmitted through the absorption unit 43 to generate electric charge.

In the imaging pixel 12, the first and second light beams 61 and 62 that have passed through the first and second pupil regions of the exit pupil of the imaging optical system 31 are transferred through the microlens 44 and the color filter 51 to the photoelectric conversion unit. 42. The photoelectric conversion unit 42 of the imaging pixel 12 photoelectrically converts the first and second light beams 61 and 62 to generate electric charge.

The charge photoelectrically converted by the photoelectric conversion unit 42 of each pixel is transferred to the accumulation 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 section 54 . The first electrode 45 a and the second electrode 45 b constitute part of an output section that outputs a signal based on the charge generated by the photoelectric conversion section 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 charge. The AF pixel 13 photoelectrically converts the second light flux 62 that has passed through the second pupil region and outputs a second signal Sig2 based on the accumulated charges. The imaging pixel 12 photoelectrically converts the first luminous flux 61 and the second luminous flux 62 and outputs a signal based on the charges accumulated.

A 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 . This signal processing section includes an analog/digital conversion section (AD conversion section) that converts a signal output from a 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 absorption portion 43 of the AF pixel 11 is arranged corresponding to one of the upper half region and the lower half region of the photoelectric conversion portion 42, and the AF pixel 13 Absorbing portion 43 is arranged substantially corresponding to the other of the upper half region and the lower half region of photoelectric conversion portion 42 . For example, at least a portion of the absorption portion 43 of the AF pixel 11 is arranged in a region on the +Y direction side of the center of the photoelectric conversion portion 42 of the AF pixel 11 . At least a portion of the absorption portion 43 of the AF pixel 13 is arranged in a region on the -Y direction side of the center of the photoelectric conversion portion 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 different positions in the direction crossing the direction of incidence of light. The absorption portion 43 of the AF pixel 11 absorbs part of the second light beam 62 , and the absorption portion 43 of the AF pixel 13 absorbs part of the first light beam 61 . Accordingly, the photoelectric conversion unit 42 of the AF pixel 11 mainly receives the first light beam 61 and the photoelectric conversion unit 42 of the AF pixel 13 mainly receives the second light beam 62 . The first signal Sig1 output from the AF pixel 11 has many signal components due to 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 emitted. 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 calculated. can be calculated.

Moreover, in the present embodiment, the absorbing portion 43 is made of a material that absorbs visible light with little reflection. Therefore, stray light due to reflection can be reduced, and influence on signals generated by each pixel can be avoided. Furthermore, a part of a second planarization layer (flatness film) 82 is arranged between the absorption part 43 and the first electrode 45a. As a result, the flatness of the absorbing portion 43 can be improved, and variations in the characteristics of the absorbing portion 43 of each pixel can be suppressed. Note that the absorption section 43 may be arranged on the first electrode 45a of the photoelectric conversion section 42 without providing the second planarization layer 82 .

If a light-shielding film (metal light-shielding film) made of a metal material for phase difference detection is to be formed on an imaging device in which a photoelectric conversion film made of an organic material is arranged, the metal light-shielding film must be formed in a predetermined pattern. , which may damage other layers (films) such as the photoelectric conversion film and the transparent electrode. In this case, it is conceivable that the characteristics of the photoelectric conversion film and the transparent electrode deteriorate, the dark current increases, and the quality of the pixel signal deteriorates, resulting in a decrease in focus detection accuracy. In addition, when the metal light shielding film is arranged directly above the photoelectric conversion film, a load capacitance (parasitic capacitance) occurs between the metal light shielding film and the photoelectric conversion film and between the metal light shielding film and the signal line for controlling the pixels. occurs, the pixels cannot be driven at high speed, and the image sensor 22 may not be operated at high speed.

Moreover, generally, it is difficult to form a metal film in an organic film, and it is difficult to dispose a metal light-shielding film in a planarizing film made of an organic material. Therefore, when the metal light-shielding film is arranged, there is a possibility that a difference in level occurs between the pixels, resulting in 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 imaging element 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 etchant for a metal light-shielding film. It is formed. Therefore, it is possible to suppress damage to other layers and prevent deterioration of pixel characteristics. In addition, it is possible to prevent the load capacity from being generated as described above, and to avoid the deterioration of the processing speed.

Next, an operation example of the camera 1 according to this 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. be done. The focus detection unit 21b of the body control unit 21 uses the first signal Sig1 and the second signal Sig output from the AF pixels 11 and 13 of the imaging device 22 to calculate the defocus amount by a phase difference detection method. . Based on the defocus amount calculated by the focus detection section 21b, the lens control section 32 moves the focus lens of the photographing optical system 31 to the in-focus position to adjust the focus. Note that instead of moving the focus lens, the imaging device 22 may be moved in the direction of the optical axis L1 of the imaging optical system 31 .

The image data generator 21 a of the body controller 21 generates image data based on the signals output from the imaging pixels 12 of the imaging device 22 . The image data generator 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. Image data for recording is recorded in the memory 23 .

According to the embodiment described above, the following effects are obtained.
(1) The imaging device 22 includes a first microlens 44 into which the first light 61 and the second light 61 that have passed through the optical system are incident, and a first photoelectric conversion device that photoelectrically converts the light to generate an electric charge. 42 , the first microlens 44 and the first photoelectric conversion unit 42 , and a first absorption unit 43 that absorbs part of the second light 62 that has passed through the first microlens 44 . a second microlens 44 into which the first light 61 and the second light 62 are incident; a second photoelectric conversion unit 42 that photoelectrically converts light to generate electric charge; and a second absorption portion 43 which is provided between the second microlens 44 and the second photoelectric conversion portion 42 and absorbs part of the first light 61 transmitted through the second microlens 44 . 2 pixels 13; In the present embodiment, the imaging element 22 includes the AF pixel 11 having the absorption portion 43 that absorbs part of the second light beam 62 and the AF pixel 11 having the absorption portion 43 that absorbs part of the first light beam 61 . A pixel 13 is arranged. Therefore, by using the signals output from the AF pixels 11 and 13, it is possible to obtain information on the phase difference of the subject image. Using the signals output from the AF pixels 11 and 13, it is possible to calculate the amount of image shift and calculate the amount of defocus.

(2) The imaging device 1 includes the imaging device 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 imaging element 22 converts the first signal Sig1 based on the charges obtained by photoelectrically converting the first light flux 61 and the second signal Sig2 based on the charges obtained by photoelectrically converting the second light flux 62 into Output to body control unit 21 . Therefore, the focus detection section 21b of the body control section 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 section 21b.

The following modifications are also within the scope of the present invention, and it is also possible to combine one or more of the modifications with the above-described embodiments.

(Modification 1)
FIG. 4 is a diagram showing a configuration example of a pixel of an imaging device according to Modification 1. As shown in FIG. The imaging device 22 according to this modified example has absorption portions 47 provided between adjacent pixels. In the example shown in FIG. 4, the absorber 47 is provided in the second planarization layer 82 and at the boundary between adjacent pixels. In the camera 1, abnormal light (ghost light) occurs due to the light passing through the photographing optical system 31 being reflected by the inside of the housing of the camera body 2 and the microlenses 44 of the image pickup device 22, and the like. Light with a large incident angle may enter the microlens 44 .

In this modified example, part of the ghost light that has passed through the microlenses 44 and the color filter 51 enters the absorption section 47 and is absorbed by the absorption section 47 . As a result, light leaking from a certain pixel to the photoelectric conversion unit 42 of the adjacent pixel can be reduced. Therefore, it is possible to suppress the signal component due to the light leaked from the adjacent pixel from being mixed into the signal generated by the pixel. To prevent the deterioration of the accuracy of the defocus amount calculated using the signals output from the AF pixels 11 and 13 and the deterioration of the image quality of the image generated using the signals output from the imaging pixels 12. be able to. It should be noted that the above description applies to the effects of various types of incident light with large incident angles.

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

The transmittance of the absorption portion 43 changes depending on the shape of the absorption portion 43, and the amount of light received by the photoelectric conversion portion 42 changes. Therefore, the incident angle of the light incident on the AF pixel and the output from the AF pixel differ between the case where the absorbing portion 43 does not have the inclined surface 48 (FIG. 3) and the case where the absorbing portion 43 has the inclined surface 48 (FIG. 5). The relationship between the signal level of the received signal 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 indicates the signal level of the signal output from the AF pixel, and the horizontal axis indicates the incident angle of light incident on the AF pixel. A waveform 61a indicates the signal level of the output signal of the AF pixel 11 when there is no inclined surface 48, and the waveform 61b indicates the signal level of the output signal of the AF pixel 11 when the inclined surface 48 is present. A waveform 62a indicates the signal level of the output signal of the AF pixel 13 when there is no inclined surface 48, and a waveform 62b indicates the signal level of the output signal of the AF pixel 13 when the inclined surface 48 is present. 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 waveforms with the inclined surface 48 is gentler. When there is an inclined surface 48, the incident light is gradually absorbed by the absorbing portion 43 as the incident angle becomes smaller (closer to 0), so the inclination of the waveforms (61b, 62b) becomes gentler. By providing the inclined surface 48 at the end of the absorbing portion 43 in this manner, the pupil division characteristics 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 curved as shown in FIGS. 7(a) and 7(b). Further, as shown in FIG. 8, the width of the absorbing portion 43 may be increased in the upward direction (−Z direction side). Assuming that 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 such that Wb2<Wt2. The area of the upper portion of the absorbent portion 43 is larger than the area of the lower portion of the absorbent portion 43 . By adjusting the shape of the absorbing portion 43 in this manner, the pupil division characteristics of the AF pixels can be adjusted. Further, a plurality of types of AF pixel pairs (AF pixel 11, AF pixel 13) having inclined surfaces 48 with different inclinations may be arranged. In this case, the camera 1 may select AF pixel pairs to be used for focus detection from among multiple types of AF pixel pairs.

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

(Modification 4)
In the embodiment described above, an example in which a 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 a primary color system (RGB) color filter is used for the imaging device 22 has been described, but a complementary color system (CMY) color filter may be used.

(Modification 6)
The imaging elements and imaging devices described in the above embodiments and modifications are applicable to cameras, smartphones, tablets, cameras built into PCs, vehicle-mounted cameras, cameras mounted on unmanned aerial vehicles (drones, radio-controlled machines, etc.), etc. may be
Moreover, you may use the absorption part mentioned above as a filter (band-pass filter) which blocks visible light and transmits infrared light. In this case, the photoelectric conversion unit efficiently receives the infrared light, enabling focus detection using the infrared light. camera) can also be applied.

Although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other aspects conceivable within the scope of the technical idea of the present invention are also included in 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... Imaging optical system 42... Photoelectric conversion part , 44... Microlens, 43... Absorber, 45a... First electrode, 45b... Second electrode, 51... Color filter, 81... First planarization layer, 82... Second planarization layer, 110... substrate

Claims (14)

a first microlens, a first photoelectric conversion unit photoelectrically converting light transmitted through the first microlens to generate an electric charge, and for outputting the electric charge generated by the first photoelectric conversion unit provided between the first electrode and the first microlens and the first electrode, and out of the first light and the second light transmitted through the first microlens, the second light a first absorption part that absorbs part of the light ;
a second microlens, a second photoelectric conversion unit photoelectrically converting light transmitted through the second microlens to generate an electric charge, and for outputting the electric charge generated by the second photoelectric conversion unit provided between the second electrode and the second microlens and the second electrode, and out of the first light and the second light transmitted through the second microlens, a second absorption part that absorbs part of the light of 1 ;
An image sensor. In the imaging device according to claim 1 ,
The first microlens and the second microlens are configured to receive the first light transmitted through a first region of the optical system and the second light transmitted through a second region different from the first region of the optical system. 2 image sensor that transmits light. In the imaging device according to claim 1 or claim 2 ,
The first photoelectric conversion section photoelectrically converts the first light transmitted through the first microlens and the light transmitted through the first microlens and the first absorption section. generate an electric charge,
The second photoelectric conversion section photoelectrically converts the second light transmitted through the second microlens and the light transmitted through the second microlens and the second absorption section. An image sensor that generates an electric charge. In the imaging device according to any one of claims 1 to 3 ,
In a direction intersecting the direction in which the light transmitted through the first microlens is incident, the length of the first absorption portion is closer to the first microlens than to the first photoelectric conversion portion. is short,
In a direction intersecting the direction in which the light transmitted through the second microlens is incident, the length of the second absorbing portion is closer to the second microlens than to the second photoelectric conversion portion. short image sensor. In the imaging device according to any one of claims 1 to 4,
In the direction crossing the direction in which the light transmitted through the first microlens is incident, the area of the first absorption portion is larger on the first microlens side than on the first photoelectric conversion portion side. small,
In the direction crossing the direction in which the light transmitted through the second microlens is incident, the area of the second absorbing portion is larger on the second microlens side than on the second photoelectric conversion portion side. small image sensor. In the imaging device according to any one of claims 1 to 4,
In a direction intersecting the direction in which the light transmitted through the first microlens is incident, the length of the first absorption portion is closer to the first microlens than to the first photoelectric conversion portion. is long,
In a direction intersecting the direction in which the light transmitted through the second microlens is incident, the length of the second absorbing portion is closer to the second microlens than to the second photoelectric conversion portion. long image sensor. In the imaging device according to any one of claims 1 to 4,
In the direction crossing the direction in which the light transmitted through the first microlens is incident, the area of the first absorption portion is larger on the first microlens side than on the first photoelectric conversion portion side. big,
In the direction crossing the direction in which the light transmitted through the second microlens is incident, the area of the second absorbing portion is larger on the second microlens side than on the second photoelectric conversion portion side. large image sensor. In the imaging device according to any one of claims 1 to 7 ,
An imaging device comprising a planarizing 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. In the imaging device according to any one of claims 1 to 8 ,
The imaging device, wherein the first absorption section and the second absorption section are black filters. In the imaging device according to any one of claims 1 to 9 ,
The imaging device, wherein the first absorption section and the second absorption section are made of an organic material. In the imaging device according to any one of claims 1 to 10 ,
The imaging device, wherein the first photoelectric conversion unit and the second photoelectric conversion unit are photoelectric conversion units made of an organic material. In the imaging device according to any one of claims 1 to 11 ,
a third electrode for outputting the charge generated by the first photoelectric conversion unit;
a fourth electrode for outputting the charge generated by the second photoelectric conversion unit,
The first photoelectric conversion unit is provided between the first electrode and the third electrode,
A said 2nd photoelectric conversion part is an image pick-up element provided between a said 2nd electrode and a said 4th electrode. In the imaging device according to any one of claims 1 to 12 ,
a first output unit that outputs a first signal used for focus detection based on the charge generated by the first photoelectric conversion unit;
a second output unit that outputs a second signal used for focus detection based on the charge generated by the second photoelectric conversion unit;
An image sensor. The imaging device according to claim 13 ;
a detection unit that performs focus detection of an optical system based on the first signal and the second signal;
An imaging device comprising:

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