JP2015115527A - Solid state image pickup device and camera system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid state image pickup device which facilitates reduction in the size and cost of a system, and allows for simultaneous acquisition of the color image and distance information of a subject, and to provide a camera system.SOLUTION: A solid state image pickup device has a pixel array and a subject distance detector. The pixel array includes a distance measurement pixel 30. The distance measurement pixel 30 is a pixel for detecting the light intensity required for determining the distance in a subject distance detector. The distance measurement pixel 30 includes a first diffraction grating 41 and a second diffraction grating 42. The first diffraction grating 41 diffracts the light incident to the distance measurement pixel 30. The first diffraction grating 41 is located on the incident side for a photoelectric conversion section 40. The second diffraction grating 42 diffracts the light passed through the first diffraction grating 41. The second diffraction grating 42 is located between the photoelectric conversion section 40 and the first diffraction grating 41.

Description

  Embodiments described herein relate generally to a solid-state imaging device and a camera system.

  Conventionally, a camera system that can simultaneously acquire a color image of a subject and distance information has been proposed. This camera system is required in various fields such as TV and game operations, monitoring of intruders by security systems, gesture recognition and motion recognition for avoiding collisions with pedestrians and vehicles by vehicles, and camera refocusing. ing.

  When an image sensor for acquiring a color image and a distance sensor for acquiring distance information are mounted on a camera system, the structure of the camera system becomes complicated, making it difficult to reduce the size and increasing the cost. It becomes a problem.

JP 2011-243862 A

  An object of one embodiment of the present invention is to provide a solid-state imaging device and a camera system that can easily reduce the size and cost of the system and can simultaneously acquire a color image of a subject and distance information. .

  According to one embodiment of the present invention, a solid-state imaging device includes a pixel array and a subject distance detection unit. The pixel array includes a plurality of pixels. The plurality of pixels are arranged in the horizontal direction and the vertical direction. The pixel array generates a signal charge corresponding to the amount of light incident from the subject to each pixel. The subject distance detection unit detects the distance to the subject. The pixel array includes imaging pixels and ranging pixels. The imaging pixels are pixels that share and detect the signal level of each color light. The pixel for distance measurement is a pixel that detects the light intensity for obtaining the distance by the subject distance detection unit. The ranging pixel includes a photoelectric conversion unit, a first diffraction grating, and a second diffraction grating. The photoelectric conversion unit generates a charge corresponding to the light intensity. The first diffraction grating diffracts the light incident on the ranging pixel. The first diffraction grating is located on the incident side with respect to the photoelectric conversion unit. The second diffraction grating diffracts the light that has passed through the first diffraction grating. The second diffraction grating is located between the photoelectric conversion unit and the first diffraction grating.

1 is a block diagram showing a schematic configuration of a solid-state imaging device according to an embodiment. The block diagram which shows schematic structure of a camera system provided with a solid-state imaging device. The figure which shows schematic structure of the optical system with which a camera system is provided. FIG. 6 is a diagram illustrating an example of an array of imaging pixels and ranging pixels in a pixel array (part 1); FIG. 6 is a diagram illustrating an example of an array of imaging pixels and ranging pixels in a pixel array (part 2); The cross-sectional schematic diagram of the pixel for ranging. The cross-sectional schematic diagram which shows a 1st diffraction grating and a 2nd diffraction grating. The figure explaining the Talbot effect by a diffraction grating. The figure which shows the example of intensity distribution of a diffracted light at the time of making the light of 0 degree of incident angles with respect to a 1st diffraction grating and a 2nd diffraction grating. The figure which shows the example of intensity distribution of a diffracted light at the time of making the light of 20 degree of incident angles with respect to a 1st diffraction grating and a 2nd diffraction grating. The figure showing the example of the relationship between the light intensity detected by the pixel for ranging, and an incident angle. FIG. 3 is a diagram illustrating a relationship between a focus state of an imaging optical system and an incident angle of light on a pixel array (part 1). FIG. 2 is a diagram illustrating a relationship between a focus state of an imaging optical system and an incident angle of light on a pixel array (part 2). FIG. 3 is a diagram illustrating a relationship between a focus state of the imaging optical system and an incident angle of light on the pixel array (part 3);

  Exemplary embodiments of a solid-state imaging device and a camera system will be described below in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment.

(Embodiment)
FIG. 1 is a block diagram illustrating a schematic configuration of a solid-state imaging apparatus according to the embodiment. FIG. 2 is a block diagram illustrating a schematic configuration of a camera system including the solid-state imaging device. The camera system 1 is a digital camera, for example. The camera system 1 may be either a digital still camera or a digital video camera. The camera system 1 may be an electronic device (for example, a mobile terminal with a camera) provided with the camera module 2.

  The camera system 1 includes a camera module 2 and a post-processing unit 3. The camera module 2 includes an imaging optical system 4 and a solid-state imaging device 5. The post-processing unit 3 includes an image signal processor (ISP) 6, a storage unit 7, and a display unit 8.

  The imaging optical system 4 takes in light from a subject and forms a subject image. The solid-state imaging device 5 captures a subject image. The ISP 6 performs signal processing of an image signal obtained by imaging with the solid-state imaging device 5. The storage unit 7 stores an image that has undergone signal processing in the ISP 6. The storage unit 7 outputs an image signal to the display unit 8 in accordance with a user operation or the like.

  The display unit 8 displays an image according to the image signal input from the ISP 6 or the storage unit 7. The display unit 8 is, for example, a liquid crystal display. The camera system 1 performs feedback control of the camera module 2 based on data that has undergone signal processing in the ISP 6.

  The solid-state imaging device 5 includes an image sensor 10 that is an imaging element and a signal processing circuit 11 that is an image processing device. The image sensor 10 is, for example, a CMOS image sensor. The image sensor 10 may be a CCD in addition to a CMOS image sensor.

  The image sensor 10 includes a pixel array 12, a vertical shift register 13, a timing control unit 14, a correlated double sampling unit (CDS) 15, an analog / digital conversion unit (ADC) 16, and a line memory 17.

  The pixel array 12 is provided in the imaging region of the image sensor 10. The pixel array 12 includes a plurality of pixels arranged in an array in the horizontal direction (row direction) and the vertical direction (column direction). Each pixel includes a photodiode that is a photoelectric conversion element. The pixel array 12 generates signal charges corresponding to the amount of light incident on each pixel.

  The timing control unit 14 supplies a vertical synchronization signal to the vertical shift register 13 instructing the timing for reading a signal from each pixel of the pixel array 12. The timing control unit 14 supplies timing signals for instructing drive timing to the CDS 15, the ADC 16, and the line memory 17, respectively.

  The vertical shift register 13 selects the pixels in the pixel array 12 for each row in accordance with the vertical synchronization signal from the timing control unit 14. The vertical shift register 13 outputs a read signal to each pixel in the selected row. The pixel to which the readout signal is input from the vertical shift register 13 outputs the signal charge accumulated according to the amount of incident light. The pixel array 12 outputs a signal from the pixel to the CDS 15 via the vertical signal line.

  The CDS 15 performs correlated double sampling processing for reducing fixed pattern noise on the signal from the pixel array 12. The ADC 16 converts an analog signal into a digital signal. The line memory 17 stores the signal from the ADC 16. The image sensor 10 outputs a signal accumulated in the line memory 17.

  The signal processing circuit 11 performs various kinds of signal processing on the image signal from the image sensor 10. The signal processing circuit 11 includes a subject distance detection unit 18 and a lens drive control unit 19. The subject distance detection unit 18 detects the subject distance. The subject distance is a distance from the imaging surface of the solid-state imaging device 5 to the subject. The lens drive control unit 19, which is a focus adjustment unit, adjusts the focus of the imaging optical system 4 by controlling the driving of the lenses constituting the imaging optical system 4.

  In addition, the signal processing circuit 11 performs various signal processing such as scratch correction, gamma correction, noise reduction processing, lens shading correction, white balance adjustment, distortion correction, resolution restoration, and the like. In FIG. 1, the components other than the subject distance detection unit 18 and the lens drive control unit 19 are omitted from the configuration of the signal processing circuit 11.

  The solid-state imaging device 5 outputs an image signal that has undergone signal processing in the signal processing circuit 11 to the outside of the chip. The solid-state imaging device 5 performs feedback control of the image sensor 10 based on data that has undergone signal processing in the signal processing circuit 11.

  The camera system 1 may be configured such that the ISP 6 of the post-stage processing unit 3 performs at least one of various signal processing performed by the signal processing circuit 11 in the present embodiment. In the camera system 1, both the signal processing circuit 11 and the ISP 6 may perform at least one of various signal processing. The signal processing circuit 11 and the ISP 6 may perform signal processing other than the signal processing described in the present embodiment.

  FIG. 3 is a diagram illustrating a schematic configuration of an optical system included in the camera system. The imaging lenses 21 and 22 constitute the imaging optical system 4. The lens driving mechanism 23 drives the imaging lens 22 in accordance with control by the lens drive control unit 19. The imaging optical system 4 only needs to include the imaging lens 22 driven by the lens driving mechanism 23, and the configuration is arbitrary.

  Light incident on the imaging optical system 4 from the subject enters the mirror 28 via the imaging optical system 4. The light transmitted through the mirror 28 travels to the image sensor 10 through the mechanical shutter 26. The camera system 1 captures a subject image with the image sensor 10. The light reflected by the mirror 28 travels to the finder 27 through the lens 24 and the prism 25. The optical system included in the camera system 1 is not limited to that described in the embodiment, and may be changed as appropriate.

  The plurality of pixels constituting the pixel array 12 include imaging pixels and ranging pixels. The imaging pixels are pixels that share and detect the signal level of each color light. The ranging pixels are pixels that detect the light intensity for obtaining the subject distance by the subject distance detection unit 18. The pixel for distance measurement uses a diffraction phenomenon called a Talbot effect to detect the light intensity according to the incident angle of light.

  4 and 5 are diagrams illustrating examples of the arrangement of the imaging pixels and the distance measurement pixels in the pixel array. The red (R) pixel 20R is an imaging pixel that detects R light. The green (G) pixel 20G is an imaging pixel that detects G light. The blue (B) pixel 20B is an imaging pixel that detects B light.

  The pixel array shown in FIG. 4 is in units of 2 × 2 pixel blocks. The R pixel 20R and the B pixel 20B are arranged on the diagonal of the pixel block, and the G pixel 20G and the distance measuring pixel 30 are arranged on the remaining diagonal. The ranging pixel 30 has the same pixel size as the imaging pixel. The pixel array 12 includes a 2 × 2 pixel block including the ranging pixels 30 and a 2 × 2 pixel block in which each color pixel forms a Bayer array. For example, the pixel block including the distance measurement pixels 30 is arranged at a position in the pixel array 12 where measurement of the subject distance is desired. The pixel block including the ranging pixels 30 may be arranged at any position in the pixel array 12.

  In the pixel array shown in FIG. 5, the pixel size of the ranging pixels 30 is the same as that of a 2 × 2 pixel block made up of imaging pixels. In this pixel block, the R pixel 20R, the G pixel 20G, and the B pixel 20B form a Bayer array. The pixel array 12 includes a pixel block made up of imaging pixels and ranging pixels 30. The distance measurement pixels 30 are arranged, for example, at positions where measurement of the subject distance is desired in the pixel array 12. The ranging pixels 30 may be arranged at any position in the pixel array 12.

  The pixel array 12 may be an array of imaging pixels and ranging pixels 30 in any manner. The arrangement of the imaging pixels and ranging pixels 30 in the pixel array 12 is not limited to those shown in FIGS. 4 and 5 and may be changed as appropriate.

  FIG. 6 is a schematic cross-sectional view of a distance measuring pixel. The ranging pixel 30 is configured by laminating a semiconductor substrate 31, a metal layer 32, an interlayer insulating film 33, a spacer layer 34, a metal layer 35, an interlayer insulating film 36, and a protective film 37. The ranging pixel 30 includes two diffraction gratings 41 and 42.

  The silicon substrate that is the semiconductor substrate 31 includes the photoelectric conversion unit 40. The photoelectric conversion unit 40 generates a charge corresponding to the light intensity. The photoelectric conversion unit 40 is, for example, a photodiode. The photoelectric conversion unit 40 includes a charge accumulation region that accumulates the generated charges.

  The metal layer 32 is provided on the semiconductor substrate 31. The metal layer 32 is a second layer including the second diffraction grating 42. The second diffraction grating 42 is a diffraction grating located between the photoelectric conversion unit 40 and the first diffraction grating 41 among the two diffraction gratings 41 and 42. The interlayer insulating film 33 is formed of a silicon oxide film or a silicon nitride film. The interlayer insulating film 33 relaxes the step of the second diffraction grating 42 and provides a flat surface.

  The spacer layer 34 is a layer having a thickness so that the second diffraction grating 42 and the first diffraction grating 41 form a certain distance. The spacer layer 34 is made of, for example, silicon oxide. The spacer layer 34 and the interlayer insulating film 33 may be integrally formed of the same material.

  The metal layer 35 is provided on the spacer layer 34. The metal layer 35 is a first layer including the first diffraction grating 41. The first diffraction grating 41 is a diffraction grating located on the incident side with respect to the photoelectric conversion unit 40 and the second diffraction grating 42 among the two diffraction gratings 41 and 42. The interlayer insulating film 36 is formed of a silicon oxide film or a silicon nitride film. The interlayer insulating film 36 relaxes the step of the first diffraction grating 41 and provides a flat surface. The protective film 37 protects the surface of the distance measuring pixel 30. The protective film 37 is, for example, a silicon nitride film.

  The distance measuring pixel 30 can be manufactured, for example, by the same manufacturing process as that for the imaging pixel. The distance measuring pixels 30 can be produced at a lower cost than the case where a manufacturing process different from that for the imaging pixels is required.

  FIG. 7 is a schematic cross-sectional view showing the first diffraction grating and the second diffraction grating. The first diffraction grating 41 diffracts the light incident on the ranging pixel 30. The first diffraction grating 41 includes a grating pattern in which a plurality of blocks that are light shielding portions are arranged at regular intervals. Each block is formed in a line shape with one direction as a longitudinal direction. In the first diffraction grating 41 shown in FIG. 7, the depth direction of the paper surface is the longitudinal direction of each block. This block of metal layer 35 blocks light. The part of the space between the blocks allows light to pass through.

  The second diffraction grating 42 diffracts the light that has passed through the first diffraction grating 41. The second diffraction grating 42 includes a grating pattern in which a plurality of blocks that are light shielding portions are arranged at regular intervals. Each block is formed in a line shape with one direction as a longitudinal direction. In the second diffraction grating 42 shown in FIG. 7, the depth direction of the paper surface is the longitudinal direction of each block. This block of metal layer 32 blocks light. The part of the space between the blocks allows light to pass through.

  For example, the width of each block constituting the second diffraction grating 42 is the same as the width of each block constituting the first diffraction grating 41. The width of the space between the blocks of the second diffraction grating 42 is the same as the width of the space between the blocks of the first diffraction grating 41.

  In the present embodiment, the blocks and spaces of the first diffraction grating 41 and the blocks and spaces of the second diffraction grating 42 have the same width. The grating pattern of the second diffraction grating 42 is replaced with the grating pattern of the first diffraction grating 41 in the positions of blocks and spaces. In the first diffraction grating 41 and the second diffraction grating 42, for example, a silicon oxide film is filled in a space between blocks.

  For example, the metal layers 32 and 35 are formed by laminating a titanium (Ti) layer 43, a titanium nitride (TiN) layer 44, and an aluminum (Al) layer 45. The Ti layer 43 has a thickness of 11 nm, for example. The TiN layer 44 has a thickness of 22 nm, for example. The Al layer 45 is configured to have a thickness greater than that of the Ti layer 43 and the TiN layer 44, for example. In addition, the metal layers 32 and 35 should just be comprised with the metal member, and are not restricted to what is demonstrated by this embodiment.

FIG. 8 is a diagram for explaining the Talbot effect by the diffraction grating. The Talbot effect is one of the light diffraction phenomena. When light is incident on the diffraction grating, the same pattern as the diffraction grating is periodically reproduced in units of a certain depth (self-imaging effect). ). When the pitch of the pattern of the diffraction grating P, and the wavelength of light lambda, Talbot distance Z _T is approximated by the following equation (1).
Z _T = 2P ² / λ (1)

According to Talbot effect, based on the half Z _{T /} 2 of the Talbot distance, the position of the even multiple of Z T _{/ 2,} the self-image of the diffraction grating emerges. In addition, an image having a half-cycle shift (inverted phase) with respect to the self image appears at a position that is an odd multiple of Z _T / 2.

The distance H between the first diffraction grating 41 and second diffraction grating 42 in the Z direction is the depth direction corresponds to half the Talbot distance Z _T of the first diffraction grating 41 and second diffraction grating 42. The distance H satisfies the relationship of the following formula (2). The first diffraction grating 41 and the second diffraction grating 42 have patterns with the same pitch P.
H = Z _T / 2 = 2P ² / 2λ (2)

For example, when the pitch P of the first diffraction grating 41 and the second diffraction grating 42 is 440 nm and the wavelength λ is 540 nm which is the wavelength of G light, the distance H is calculated as 358 nm by the above equation (2). . Thus, the distance H is set according to the pitch P. Note that the Talbot distance _{Z T} at this time is calculated as 717Nm.

  The ranging pixel 30 is configured such that the distance between the first diffraction grating 41 and the second diffraction grating 42 is a distance H that satisfies the above equation (2). The first diffraction grating 41 generates an image whose phase is inverted with respect to the self image at the position of the second diffraction grating 42. In the following description, an image whose phase is reversed with respect to the self image is appropriately referred to as a “reversed image”.

  The first diffraction grating 41 forms an inverted image at the position of the second diffraction grating 42 by diffracting incident light traveling in the direction perpendicular to the light receiving surface of the photoelectric conversion unit 40, that is, the Z direction which is the depth direction. To do. Since the inverted image of the first diffraction grating 41 matches the grating pattern of the second diffraction grating 42, the amount of light passing through the second diffraction grating 42 is reduced when the inverted image is formed at the position of the second diffraction grating 42. Maximum.

  FIG. 9 is a diagram illustrating an example of the intensity distribution of diffracted light when light having an incident angle of 0 degrees is incident on the first diffraction grating and the second diffraction grating. FIG. 10 is a diagram illustrating an example of the intensity distribution of diffracted light when light having an incident angle of 20 degrees is incident on the first diffraction grating and the second diffraction grating.

  Light traveling in a direction perpendicular to the light receiving surface of the photoelectric conversion unit 40 enters the first diffraction grating 41 at an incident angle of 0 degree. When the incident angle of the light incident on the ranging pixel 30 is 0 degree, the light intensity that passes through the second diffraction grating 42 is maximized, so that the light intensity detected by the photoelectric conversion unit 40 is maximized.

  When the incident angle of the light incident on the ranging pixel 30 is changed from 0 degree, the inverted image at the position of the second diffraction grating 42 is blurred, so that the amount of light passing through the second diffraction grating 42 is reduced. When light having an incident angle of 20 degrees is incident, the light intensity detected by the photoelectric conversion unit 40 is reduced as compared with light having an incident angle of 0 degrees.

  FIG. 11 is a diagram illustrating an example of the relationship between the light intensity detected by the ranging pixel and the incident angle. As shown in FIG. 11, when the incident angle is 0 degree, the light intensity detected by the ranging pixel 30 is maximized. The greater the inclination of the incident light with respect to when the incident angle is 0 degrees, the smaller the light intensity detected by the ranging pixel 30.

  Thus, the light intensity detected by the ranging pixel 30 depends on the incident angle of light. The first diffraction grating 41 and the second diffraction grating 42 cause the light having an intensity corresponding to the incident angle of the light to the ranging pixel 30 to travel to the photoelectric conversion unit 40. In addition, when the incident angle is 0 degree, the incident angle when the light traveling direction is tilted in a predetermined direction is indicated as plus, and when the light traveling direction is tilted in the opposite direction to the plus angle The incident angle is shown as minus.

  Next, an operation for detecting a subject distance by the solid-state imaging device 5 will be described. For example, the camera system 1 can be switched between a distance detection mode for detecting a subject distance and a normal shooting mode.

  In the distance detection mode, the solid-state imaging device 5 detects the light intensity by each distance measurement pixel 30 while driving the imaging lens 22 under the control of the lens drive control unit 19. The subject distance detection unit 18 captures the detection result of the light intensity by each distance measurement pixel 30 every time the amount of extension of the imaging lens 22 is changed.

  12 to 14 are diagrams illustrating the relationship between the focus state of the imaging optical system and the incident angle of light on the pixel array. FIG. 12 shows a state of the rear pin in which the subject 50 is not in focus and the subject 50 is in focus behind. The pixel array 12 receives light in a dispersed state before converging on the focal point. Each distance measuring pixel 30 in which light from the subject 50 is incident in the pixel array 12 detects the light intensity corresponding to the incident angle.

  The subject distance detection unit 18 obtains the incident angle of light for each distance measurement pixel 30 from the light intensity detected by each distance measurement pixel 30. The subject distance detection unit 18 grasps that the dispersed light is incident on the pixel array 12 based on the distribution of the incident angles of the light in the pixel array 12. Thereby, the subject distance detecting unit 18 grasps that the subject 50 is not in focus.

  FIG. 13 shows a state of the front pin in which the subject 50 is not in focus and the subject 50 is in front of the focus. The dispersed light after being converged on the focal point is incident on the pixel array 12. Each distance measuring pixel 30 in which light from the subject 50 is incident in the pixel array 12 detects the light intensity corresponding to the incident angle.

  The subject distance detection unit 18 obtains the incident angle of light for each distance measurement pixel 30 from the light intensity detected by each distance measurement pixel 30. The subject distance detection unit 18 grasps that the dispersed light is incident on the pixel array 12 based on the distribution of the incident angles of the light in the pixel array 12. Thereby, the subject distance detecting unit 18 grasps that the subject 50 is not in focus.

  When the subject distance detection unit 18 detects that the subject 50 is out of focus, the solid-state imaging device 5 drives the imaging lens 22 and the ranging pixels 30 until the subject 50 is in focus. The detection of the light intensity at is repeated.

  FIG. 14 shows a state where the subject 50 is in focus. The light incident on the pixel array 12 converges on the focal point on the light receiving surface in the pixel array 12. Each distance measuring pixel 30 in which light from the subject 50 is incident in the pixel array 12 detects the light intensity corresponding to the incident angle.

  The subject distance detection unit 18 obtains the incident angle of light for each distance measurement pixel 30 from the light intensity detected by each distance measurement pixel 30. The subject distance detection unit 18 grasps that the light incident on the pixel array 12 is converged on the light receiving surface based on the distribution of the incident angles of the light in the pixel array 12. Accordingly, the subject distance detection unit 18 grasps that the subject 50 is in focus.

  The subject distance detection unit 18 obtains a subject distance based on the amount of extension of the imaging lens 22 in a state where the subject 50 is in focus. The extension amount of the imaging lens 22 is a focus adjustment amount by the lens drive control unit 19. For example, the subject distance detection unit 18 holds in advance a table indicating the relationship between the amount of extension of the imaging lens 22 and the subject distance. The subject distance detection unit 18 obtains a subject distance according to the amount of extension of the imaging lens 22 by referring to the table.

  According to the embodiment, the solid-state imaging device 5 obtains a color image based on the detection results of light in the R pixel 20R, the G pixel 20G, and the B pixel 20B that are imaging pixels. The solid-state imaging device 5 obtains the subject distance based on the light detection result in the distance measurement pixels 30. The solid-state imaging device 5 can acquire the color image of the subject and the distance information at the same time.

  The imaging pixels and the ranging pixels 30 are arranged in one pixel array 12. The camera system 1 can obtain a color image of a subject and distance information by a solid-state imaging device 5 including one pixel array 12. The camera system 1 can be easily reduced in size and cost compared to the case where an image sensor for acquiring a color image and a distance measuring sensor for acquiring distance information are installed.

  As described above, the solid-state imaging device 5 is advantageous in that it is easy to reduce the size and cost of the camera system 1 and to obtain a color image of the subject and distance information at the same time.

  In the camera system 1, at least one of the subject distance detection unit 18 and the lens drive control unit 19 may be provided in the ISP 6 of the post-processing unit 3. Also in this case, the camera system 1 can easily reduce the size and cost, and can obtain the effect that the color image of the subject and the distance information can be acquired simultaneously.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 Camera system, 4 Imaging optical system, 5 Solid-state imaging device, 12 Pixel array, 18 Subject distance detection part, 19 Lens drive control part, 30 Distance measuring pixel, 40 Photoelectric conversion part, 41 1st diffraction grating, 42 2nd Diffraction grating.

Claims (6)

A pixel array including a plurality of pixels arranged in a horizontal direction and a vertical direction, and generating a signal charge according to the amount of incident light from the subject to each pixel;
A subject distance detection unit for detecting a distance to the subject,
The pixel array is an imaging pixel that is the pixel that detects by sharing the signal level of each color light, and a distance measurement that is the pixel that detects the light intensity for obtaining the distance by the subject distance detection unit. A pixel, and
The ranging pixels are:
A photoelectric conversion unit for generating a charge corresponding to the light intensity in the previous period;
A first diffraction grating located on the incident side with respect to the photoelectric conversion unit and diffracting the light incident on the ranging pixel;
A solid-state imaging device comprising: a second diffraction grating that is located between the photoelectric conversion unit and the first diffraction grating and diffracts light that has passed through the first diffraction grating. The first diffraction grating and the second diffraction grating each include a grating pattern in which a light shielding part that shields light and a space between the light shielding parts are periodically arranged;
The length between the first diffraction grating and the second diffraction grating is a length set according to a pitch of the light shielding part and the space in the grating pattern. Solid-state imaging device.   3. The solid-state imaging device according to claim 2, wherein a length between the first diffraction grating and the second diffraction grating is a length corresponding to half of a Talbot distance corresponding to the pitch.   The said grating pattern of the said 2nd diffraction grating replaces the position of the said light-shielding part and the position of the said space with the said grating pattern of the said 1st diffraction grating. Solid-state imaging device. The first diffraction grating and the second diffraction grating cause light having an intensity corresponding to an incident angle of light to the ranging pixel to travel to the photoelectric conversion unit,
The subject distance detection unit determines whether the subject is in focus based on a result of obtaining the incident angle according to the light intensity detected by the ranging pixel, and determines whether the subject is in focus. The solid-state imaging device according to claim 1, wherein the solid-state imaging device is detected. An imaging optical system that captures light from the subject and forms a subject image;
A pixel array comprising a plurality of pixels arranged in a horizontal direction and a vertical direction, and generating a signal charge according to the amount of incident light from the imaging optical system to each pixel;
A subject distance detection unit for detecting a distance to the subject;
A focus adjustment unit that adjusts the focus of the imaging optical system,
The pixel array is an imaging pixel that is the pixel that detects by sharing the signal level of each color light, and a distance measurement that is the pixel that detects the light intensity for obtaining the distance by the subject distance detection unit. A pixel, and
The ranging pixels are:
A photoelectric conversion unit that generates a charge according to the light intensity;
A first diffraction grating located on the incident side with respect to the photoelectric conversion unit and diffracting the light incident on the ranging pixel;
A second diffraction grating located between the photoelectric conversion unit and the first diffraction grating and diffracting light that has passed through the first diffraction grating,
The first diffraction grating and the second diffraction grating cause light having an intensity corresponding to an incident angle of light to the ranging pixel to travel to the photoelectric conversion unit,
The subject distance detection unit determines whether or not the subject is in focus based on a result of obtaining the incident angle according to the light intensity detected by the ranging pixel. A camera system, wherein the distance is detected based on a focus adjustment amount by the focus adjustment unit in a matching state.