JP5532766B2 - Imaging device and imaging apparatus - Google Patents

Description

The present invention relates to an imaging element and an imaging apparatus .

  2. Description of the Related Art An imaging device is known in which a focus detection pixel is mixed in a large number of imaging pixels of an imaging element to obtain an imaging signal from the imaging pixel and obtain a focus detection signal from the focus detection pixel (see, for example, Patent Document 1). . In the focus detection pixel arranged in the image pickup element of the image pickup apparatus, the photodiode selectively receives the light beam from the exit pupil region of the photographing lens and performs photoelectric conversion.

JP 2008-312073 A

  However, as the focus detection pixel position moves away from the optical axis of the photographing lens, that is, depending on the F value of the photographing optical system, the light receiving region of the photodiode is deformed into an ellipse together with the shape of the exit pupil. In that case, the light receiving area of the photodiode is also elliptical, while the light receiving portion of the conventional photodiode is circular, semicircular, or rectangular, so that noise components such as stray light are received in the non-light receiving area. Therefore, in order to obtain a focus detection signal with high accuracy, there has been a problem that a correction amount with respect to the focus detection pixel output becomes large.

An image pickup device according to a first aspect of the present invention includes a first pixel including a first light receiving region having a shape corresponding to a shape of the first region on which light having passed through the first region forming the exit pupil of the optical system is incident. The first pixel is disposed at a position farther from the optical axis of the optical system than the first pixel, and has a shape corresponding to the shape of the second region where light passing through the second region forming the exit pupil enters. And a second pixel including two light receiving regions .

  According to the present invention, it is possible to output a focus detection signal with high accuracy.

It is sectional drawing which showed the whole structure of the digital still camera of an interchangeable lens mounting the image pick-up element of one Embodiment. It is the front view which showed typically the imaging | photography screen of this digital still camera. It is the front view which showed a part of imaging device. It is sectional drawing which showed the principal part of the focus detection optical system of the focus detection pixel shown in FIG. It is sectional drawing which showed the structure of the imaging pixel of FIG. It is sectional drawing which showed the structure of the focus detection pixel of FIG. It is a front view of the photoelectric conversion part which has the light shielding member in a focus detection pixel. It is a front view of the photoelectric conversion part which does not have the light shielding member in a focus detection pixel. It is the figure which showed typically the characteristic of the shape of the photoelectric conversion part of each focus detection pixel which forms a focus detection pixel row | line.

An image sensor according to an embodiment of the present invention will be described. FIG. 1 is a cross-sectional view showing the overall configuration of a lens interchangeable digital still camera equipped with an image sensor according to an embodiment. In FIG. 1, a digital still camera 100 has an interchangeable photographic lens 110 and a camera body 120, and the interchangeable lens 110 is detachably attached to the camera body 120 via a mount portion 130.

  The interchangeable lens 110 includes a photographing optical system 111 configured as a zoom lens, a diaphragm device 112 disposed in the photographing optical system 111, a lens drive control device 113, and the like. The photographing optical system 111 includes a zooming lens 111a and a focusing lens 111b. The lens drive control device 113 includes a microcomputer (not shown), a memory, a drive control circuit, and the like, and performs drive control for adjusting the focus of the focusing lens 111b and drive control for adjusting the aperture diameter of the aperture device 112. In addition, detection of the position of the zooming lens 111a, detection of the position of the focusing lens 111b, detection of the aperture diameter of the diaphragm 112, and the like are performed.

  The camera body 120 includes a solid-state image sensor 121, a body drive control device 122, a liquid crystal display element drive circuit 123, a liquid crystal display element 124 driven by the drive circuit 123, and the liquid crystal display according to an embodiment of the present invention. An eyepiece 125 for observing the element 124 and a memory card 126 for recording image data captured by the image sensor 121 are provided.

  As will be described in detail later, the imaging element 121 includes a plurality of imaging pixels that output an imaging signal, that is, an image signal, and a plurality of focus detection pixels that output a focus detection signal. The plurality of focus detection pixels and the plurality of focus detection pixels are two-dimensionally arranged such that the plurality of focus detection pixels are scattered or mixed in the plurality of focus detection pixels. The focus detection pixel is a focus detection pixel for a pupil division phase difference type focus detection device, as will be described in detail later.

  The liquid crystal display element 124 and the eyepiece lens 125 constitute an electronic viewfinder, and the photographer can observe a through image of the subject displayed on the liquid crystal display element 124 via the eyepiece lens 125.

  The body drive control device 122 includes a microcomputer (not shown), a memory, a drive control circuit, and the like. The body drive control device 122 controls the drive of the image sensor 121, reads the image signal and focus detection signal of the image sensor 121, and performs image processing of the image signal. And recording, focus detection calculation based on the focus detection signal, and overall camera operation control such as exposure control.

  The body drive control device 122 and the lens drive control device 113 exchange lens information signals and camera information signals between the camera body 120 and the interchangeable lens 110 via electrical contacts 131 provided on the mount unit 130. I do.

  Next, an outline of the operation of the interchangeable lens digital still camera will be described. The imaging optical system 111 of the interchangeable lens 110 forms a subject image on the imaging device 121. The imaging device 121 outputs an imaging signal from the imaging pixel and outputs a focus detection signal from the focus detection pixel, and these imaging signals. And a focus detection signal are sent to the body drive control device 122. The body drive control device 122 calculates a defocus amount based on the focus detection signal, and sends this defocus amount to the lens drive control device 113 via the electrical contact 131. The lens drive control device 113 calculates the lens drive amount of the focusing lens 111b based on this defocus amount, and drives the focusing lens 111b to the in-focus position according to this lens drive amount.

  The body drive control device 122 further creates a through image based on the imaging signal and displays it on the liquid crystal display element 124 via the liquid crystal display element driving circuit 123, and performs predetermined image processing on the imaging signal in accordance with the shutter release signal. To create image data and record it on the memory card 126.

FIG. 2 shows a shooting screen of the digital still camera 100. In FIG. 2, a plurality of focus detection areas are formed over the entire surface of the shooting screen 200. In this example, 27 focus detection areas are formed. Specifically, the focus detection areas 201, 201a, 201b, 202, 202a, 202b, 206, 206a, 206b, 207, 207a, 207b are horizontal in FIG. The focus detection areas 203, 203a, 203b, 204, 204a, 204b, 205, 205a, 205b, 208, 208a, 208b, 209, 209a, and 209b extend in the vertical direction. The photographing screen 200 corresponds to the imaging surface of the image sensor 121, and a plurality of focus detection pixels are arranged in the area of the image sensor 121 corresponding to each of the focus detection areas 201 to 207b.

  FIG. 3 is a front view showing a part of the image sensor 121. In FIG. 3, a large number of imaging pixels 210 are two-dimensionally arranged on a part 121 a of the imaging element 121. The imaging pixel 210 includes a red (R) pixel, a green (G) pixel, and a blue (B) pixel, and the red pixel, the green pixel, and the blue pixel are regularly arranged according to a Bayer arrangement. Each imaging pixel 210 has a photoelectric conversion unit 210a. The plurality of focus detection pixels 220 are arranged in the vertical direction and form a focus detection pixel row 215. The focus detection pixel column 215 in the image sensor 121 corresponds to, for example, the focus detection area 205 in the vertical direction of the shooting screen 200 illustrated in FIG. In this case, the focus detection pixel row 215 is arranged at a position separated from the optical axis of the photographing lens. The plurality of focus detection pixels 220 are arranged such that a part of the image pickup pixels 210 arranged in the Bayer array is replaced with the focus detection pixels 220.

  The plurality of focus detection pixels 220 includes a plurality of focus detection pixels 220A and a plurality of focus detection pixels 220B, and these focus detection pixels 220A and 220B are alternately arranged in the vertical direction. The focus detection pixel 220A has a small photoelectric conversion unit 220a located above the pixel, and the focus detection pixel 220B has a small photoelectric conversion unit 220b located below the pixel. As described above, the size of the photoelectric conversion unit 220a of the focus detection pixel 220A and the size of the photoelectric conversion unit 220b of the focus detection pixel 220B are determined to be approximately half the size of the photoelectric conversion unit 210a of the imaging pixel 210, respectively.

  Since the focus detection pixel row 215 is separated from the optical axis of the photographing lens, the photoelectric conversion unit 220a has an elliptical shape, which depends on the distance from the optical axis of the photographing lens, that is, the photographing optical system. The shape corresponds to the F value. The extending direction of the elliptical minor axis coincides with the extending direction of the focus detection pixel column 215, that is, the alignment direction of the focus detection pixels 220 forming the focus detection pixel column 215. Further, since the imaging element 121 is a finite region, the value of the ratio between the major axis and the minor axis of the ellipse is a value within a predetermined range, specifically about 1 to 4. The shape of the conventional photoelectric conversion unit is circular, semi-circular, rectangular or the like, but noise components such as stray light are received in the non-light-receiving region portion, so that the shape of the photoelectric conversion unit 220a will be described later. An elliptical shape is formed in accordance with the shape of the first part or the second part of the pupil, and the correction amount of the focus detection pixel output is reduced as compared with the prior art.

  FIG. 9 is a diagram schematically illustrating the characteristics of the shape of the photoelectric conversion unit of each focus detection pixel forming the focus detection pixel row in the image sensor 121. For convenience of explanation, FIG. 9 is a diagram in which four focus detection pixels are arranged in each focus detection pixel column. As described above, as the focus detection pixel array is separated from the optical axis of the photographing lens, the light receiving region of the photoelectric conversion unit is deformed into an ellipse together with the shape of the exit pupil. Therefore, as shown in FIG. 9, the elliptical shape of the photoelectric conversion unit of the focus detection pixel is configured so that the flatness increases in accordance with the light receiving region as the focus detection pixel row is separated from the optical axis of the photographing lens. . For example, in the focus detection pixel row 214 near the optical axis of the photographing lens, the shape of the photoelectric conversion unit of the focus detection pixel is substantially circular, but in the focus detection pixel row 215 slightly separated from the optical axis of the photographing lens, The photoelectric conversion units 220a and 220b of the focus detection pixels 220A and 220B have a flat elliptical shape.

  As described above, the shape of the photoelectric conversion unit of the focus detection pixel in the same image sensor varies depending on the focus detection pixel array in which the focus detection pixel is arranged. The ratio of the major axis to the minor axis of the elliptical shape of the photoelectric conversion unit of the focus detection pixel, in which the flatness increases as the focus detection pixel array moves away from the optical axis of the photographic lens, is approximately the value of an image sensor of a normal digital still camera. It is preferable that it is 2-3.

FIG. 4 is a cross-sectional view showing the main part of the focus detection optical system of the focus detection pixel 220 shown in FIG. 4, the photoelectric conversion unit 220a of the focus detection pixels 220 A receives the light beam 241 that has passed through the first portion 240a of the exit pupil 240 of the imaging optical system via the microlens array 250, the focus detection pixels 220 B The photoelectric conversion unit 220 b receives the light beam 242 transmitted through the second portion 240 b of the exit pupil 240 through the microlens array 250. Thus, by measuring the phase difference between the focus detection signal sequence of the focus detection signal sequence and a plurality of focus detection pixels 220 B of the photoelectric conversion unit 220b of the photoelectric conversion unit 220a of the plurality of focus detection pixel 220 A, the defocus amount Can be calculated.

  Next, an embodiment of an image sensor according to the present invention will be described with reference to FIGS. FIG. 5 is a cross-sectional view showing the configuration of the imaging pixel of FIG. The imaging pixel 210 includes a photoelectric conversion unit 210a, a light shielding mask 261, a planarization layer 262, a color filter 263, a planarization layer 264, and a microlens 265.

  More specifically, the photoelectric conversion unit 210a is formed on the semiconductor substrate 260, and a light shielding mask 261 is provided immediately above the photoelectric conversion unit 210a. The light shielding mask 261 shields the outer periphery of the photoelectric conversion unit 210a and defines a light receiving region of the photoelectric conversion unit 210a. Thus, the opening 261a of the light shielding mask 261 defines the light receiving area of the photoelectric conversion unit 210a and corresponds to the size of the photoelectric conversion unit 210a of the imaging pixel 210 in FIG. A planarizing layer 262 is stacked on the light shielding mask 261, and a color filter 263 is formed on the planarizing layer 262. These color filters 263 have spectral characteristics corresponding to the red (R) pixel 210, the green (G) pixel 210, and the blue (B) pixel 210 shown in FIG. A planarizing layer 264 is laminated on the color filter 263, and each microlens 265 of the microlens array 250 shown in FIG. 4 is disposed on the planarizing layer 264.

The color filter 263 is a photonic crystal color filter in which a high refractive inorganic material and a low refractive inorganic material are laminated in multiple layers. TiO ₂ is used as the high refractive inorganic material, and SiO ₂ is used as the low refractive inorganic material. In this photonic crystal color filter, color fractors having spectral characteristics of red, green and blue are adjusted by adjusting the film thicknesses of the high refractive material TiO ₂ and the low refractive material SiO ₂ having a multilayer structure. Can be created. The high refractive inorganic material and the low refractive inorganic material are not limited to TiO ₂ and SiO ₂ , respectively, and other inorganic materials can be used. For example, SiN can be used instead of TiO ₂ .

6 is a cross-sectional view showing the configuration of the focus detection pixel of FIG. The focus detection pixels 220 A and 220 B include photoelectric conversion units 220 a and 220 b , a light shielding mask 261, a planarization layer 262, a neutral density filter 266, a planarization layer 264, and a microlens 265.

More specifically this configuration, the photoelectric conversion unit 220a and the focus detection pixels 220 a photoelectric conversion unit 220b of the B of the focus detection pixels 220 A are respectively formed on the semiconductor substrate 260, these photoelectric conversion unit 220a, 220b immediately on the Is provided with a light shielding mask 261. The light shielding mask 261 shields approximately half of the photoelectric conversion unit 220a and approximately half of the photoelectric conversion unit 220b, thereby defining the light receiving regions of the photoelectric conversion units 220a and 220b. Thus, the opening 261a of the light shielding mask 261 defines the light receiving area of the photoelectric conversion units 220a and 220b, and thus corresponds to the size of the photoelectric conversion units 220a and 220b of the focus detection pixels 220A and 220b in FIG.

A planarizing layer 262 is stacked on the light shielding mask 261, and a neutral density filter 266 is formed on the planarizing layer 262. The neutral density filter 266 is formed in the same layer as the color filter 263 of the imaging pixel 210, that is, is formed at the same height position as the height of the color filter 263. The neutral density filter 266 is also a photonic crystal filter, and is a multilayer structure of the same inorganic material as the color filter 263. That is, the neutral density filter 266 is a multilayer laminate of a high refractive inorganic material TiO ₂ and a low refractive inorganic material SiO ₂ . The neutral density filter 266 has spectral characteristics that transmit the entire visible light range, that is, adds the spectral characteristics of the color filter of the red pixel, the spectral characteristics of the color filter of the green pixel, and the spectral characteristics of the color filter of the blue pixel. Spectral characteristics as described above.

The function of the neutral density filter 266 is as follows. That is, since the imaging pixel 210 has the color filter 263, the amount of light incident on the photoelectric conversion unit 210 a of the imaging pixel 210 is reduced by the color filter 263. On the other hand, in order to focus detection pixel 220 A, 220 B there is no color filter, exceeds the output signal level of the imaging pixel 210 is the output signal level of the focus detection pixels 220 A, 220 B, prior to the image-capturing pixels 210 saturated There is a risk of doing. In order to prevent such saturation of the output signal level of the focus detection pixels 220 A and 220 B , the neutral density filter 266 captures the amount of light incident on the photoelectric conversion units 220 a and 220 b of the focus detection pixels 220 A and 220 B. The amount of incident light on the photoelectric conversion units 220a and 220b is reduced so as to be equal to or less than the amount of incident light on the photoelectric conversion unit 210a of the pixel 210.

The manufacturing of the imaging pixel 210 and the focus detection pixels 220 A and 220 B is as follows. First, the photoelectric conversion units 210 a, 220 a, and 220 b are simultaneously formed on the semiconductor substrate 260. Thereafter, a light shielding mask 261 is formed, and a planarization layer 262 is further laminated. Thereafter, R, G, and B color filters 263 are sequentially formed by stacking a high refractive inorganic material and a low refractive inorganic material. Thereafter, the neutral density filter 266 is formed by laminating the same inorganic material as the color filter 263. Of course, the color filter 263 can be created after the neutral density filter 266 is created first. Thereafter, a planarization layer 264 and a microlens 265 are formed. In this way, the color filter 263 and the neutral density filter 266 can be made of the same inorganic material, so that the manufacturing process of the image sensor 121 is simplified.

As shown in FIG. 7, the focus detection pixel 220A, the light-shielding mask 261 220B has a first portion 240a or oval opening 261a that matches the shape of the second portion 240b of the exit pupil 240, The outer edge of the light beam 284 that has passed through the microlens 265 is shielded from light. Accordingly, the photoelectric conversion unit, when receiving incident light from the opening portion 261a, the shape of the light-receiving region and has an elliptical shape to match the shape of the first portion 240a or second portion 240b of the exit pupil 240. This produces an effect of receiving stray light and preventing noise from being superimposed on the focus detection signal.

  Note that when the photoelectric conversion units 220a and 220b of the focus detection pixels 220A and 220B receive incident light, the shape of the light receiving region is elliptical according to the shape of the first portion 240a or the second portion 240b of the exit pupil 240. 8A and 8B, the photoelectric conversion units 220a and 220b may have an elliptical shape without using the light shielding mask 261. As shown in FIGS. Further, the focus detection pixel 220A is configured in a mode in which the lower half is covered with a light shielding mask 261 as shown in FIG. 8C instead of being configured in the mode shown in FIG. The shape of the photoelectric conversion unit 220a that is not used may be an ellipse. Similarly, the focus detection pixel 220B may be configured in such a manner that the upper half is covered with the light shielding mask 261, and the shape of the photoelectric conversion unit 220b that is not covered may be an ellipse.

  According to the above-described embodiment, stray light is obtained by matching the shape of the light receiving region in the photoelectric conversion units 220a and 220b of the focus detection pixels 220A and 220B with the shapes of the first portion 240a and the second portion 240b of the exit pupil. Since the non-light-receiving region that receives the noise component such as the above is excluded, the imaging element 121 can output a focus detection signal with high accuracy.

  In the above-described embodiment, the shape of the light receiving region of the photoelectric conversion unit covered by the light shielding mask or the shape of the photoelectric conversion unit not covered itself is an ellipse including a circle, but is a regular polygon. An approximate shape such as a polygon including

121 imaging device, 210 an imaging pixel, 210a photoelectric conversion unit, 214 and 215 focus detection pixel row, 220 focus detection pixels, 220a, 220b photoelectric conversion unit, 260 a semiconductor substrate, 261 light-shielding mask, 261a opening 263 color filter, 265 Micro lens, 266 neutral density filter

Claims (21)

A first pixel including a first light receiving region having a shape corresponding to the shape of the first region on which light that has passed through the first region forming the exit pupil of the optical system is incident;
The second pixel is disposed at a position farther from the optical axis of the optical system than the first pixel, and has a shape corresponding to the shape of the second region on which light that has passed through the second region forming the exit pupil enters. An imaging device comprising: a second pixel including a light receiving region . The imaging device according to claim 1,
The first pixel outputs a focus detection signal generated according to light incident on the first light receiving region,
The imaging element , wherein the second pixel outputs a focus detection signal generated in accordance with light incident on the second light receiving region . The imaging device according to claim 1 or 2 ,
The first light receiving region has an elliptical shape,
The shape of the said 2nd light reception area | region is an elliptical shape of a shape different from the said 1st light reception area | region, The imaging device characterized by the above-mentioned. The imaging device according to claim 3 ,
The flattening ratio of the first light receiving area is different from the flatness ratio of the second light receiving area . The imaging device according to claim 4,
The imaging device , wherein the flatness ratio of the second light receiving area is higher than the flatness ratio of the first light receiving area . In the image sensor according to any one of claims 1 to 5 ,
The first pixel includes a first light shielding portion having a first opening that defines the shape of the first light receiving region,
The image sensor, wherein the second pixel includes a second light-shielding portion having a second opening that defines a shape of the second light-receiving region . In the image sensor according to any one of claims 1 to 6,
  The first pixel includes a first photoelectric conversion unit that defines a shape of the first light receiving region,
  The image sensor, wherein the second pixel includes a second photoelectric conversion unit that defines a shape of the second light receiving region. In the imaging device according to any one of claims 1 to 7,
  The first pixel and the second pixel each include a filter having a spectral characteristic that transmits the entire visible light range,
  The imaging device, wherein light transmitted through the filter is incident on the first light receiving region and the second light receiving region. In the imaging device according to any one of claims 1 to 8,
  A third light receiving region having a shape corresponding to the shape of the third region on which light that has passed through the third region forming the exit pupil is incident, and is generated according to the light incident on the third light receiving region A third pixel that outputs a focus detection signal;
  The fourth pixel is disposed at a position farther from the optical axis of the optical system than the third pixel, and has a shape corresponding to the shape of the fourth region on which light that has passed through the fourth region forming the exit pupil enters. A fourth pixel that includes a light receiving region and outputs a focus detection signal generated according to light incident on the fourth light receiving region;
  The first pixel and the second pixel have an elliptical shape whose major axis is parallel to the first direction,
  The imaging element according to claim 3, wherein the third pixel and the fourth pixel have an elliptical shape whose major axis is parallel to a second direction perpendicular to the first direction. The imaging device according to claim 9,
  The shape of the third light receiving region is an elliptical shape different from the shape of the fourth light receiving region. The image sensor according to claim 10, wherein
  The flattening ratio of the third light receiving area is different from the flatness ratio of the fourth light receiving area. The imaging device according to claim 11,
  The imaging device, wherein the flatness ratio of the second light receiving area is higher than the flatness ratio of the first light receiving area. The image sensor according to any one of claims 9 to 12,
  The third pixel includes a third light shielding portion having a third opening that defines a shape of the third light receiving region,
  The image pickup device, wherein the fourth pixel includes a fourth light shielding portion having a fourth opening that defines a shape of the fourth light receiving region. The image sensor according to any one of claims 9 to 13,
  The third pixel includes a third photoelectric conversion unit that defines a shape of the third light receiving region,
  The imaging device, wherein the fourth pixel includes a fourth photoelectric conversion unit that defines a shape of the fourth light receiving region. In the imaging device according to any one of claims 9 to 14,
  The third pixel and the fourth pixel each include a filter having a spectral characteristic that transmits the entire visible light range,
  The imaging device, wherein light transmitted through the filter is incident on the third light receiving region and the fourth light receiving region. In the imaging device according to any one of claims 9 to 15,
  The first pixel and the third pixel are arranged in a first pixel region including a region through which an optical axis of the optical system passes,
  The imaging device, wherein the second pixel and the fourth pixel are arranged in a second pixel region formed around the first pixel region. The image sensor according to any one of claims 9 to 16,
  A fifth light receiving region formed between the first pixel region and the second pixel region and having a shape corresponding to the shape of the fifth region on which light that has passed through the fifth region forming the exit pupil is incident; Including a fifth pixel that outputs a focus detection signal generated according to light incident on the fifth light receiving region and a shape of the sixth region on which light that has passed through the sixth region forming the exit pupil is incident. A third pixel region including a sixth pixel that includes a sixth light-receiving region having a corresponding shape and that outputs a focus detection signal generated according to light incident on the sixth light-receiving region;
  The fifth pixel has an elliptical shape whose major axis is parallel to the first direction,
  The sixth pixel has an elliptical shape whose major axis is parallel to the second direction,
  The flatness of the fifth light receiving region is higher than the flatness of the first light receiving region and lower than the flatness of the second light receiving region,
  The flattening ratio of the sixth light receiving area is higher than that of the third light receiving area and lower than that of the fourth light receiving area. The imaging device according to any one of claims 1 to 17,
  A seventh pixel having a polygonal seventh light receiving region and outputting an image signal generated according to light incident on the seventh light receiving region;
  The eighth pixel is disposed at a position farther from the optical axis of the optical system than the seventh pixel, has an eighth light receiving region having the same shape as the seventh light receiving region, and is generated according to light incident on the eighth light receiving region. And an eighth pixel that outputs the image signal. The imaging device according to any one of claims 1 to 17,
  A seventh pixel having a circular seventh light receiving region and outputting an image signal generated according to light incident on the seventh light receiving region;
  The eighth pixel is disposed at a position farther from the optical axis of the optical system than the seventh pixel, has an eighth light receiving region having the same shape as the seventh light receiving region, and is generated according to light incident on the eighth light receiving region. And an eighth pixel that outputs the image signal. The image sensor according to any one of claims 1 to 19,
An imaging apparatus comprising: a calculation unit that calculates a defocus amount based on a focus detection signal output from the imaging element. The imaging device according to claim 20,
  The imaging optical system including a focusing lens;
An imaging apparatus, further comprising: a lens driving unit that drives the focusing lens based on the defocus amount calculated by the calculation unit.

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