JP2018026604A - Imaging device and imaging device system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging device capable of always using the same image information as a photographic image respective of whether a main mirror exists on an optical path of a photographic optical system.SOLUTION: An imaging device comprises: an imaging element 14 which images a subject formed by a photographic optical system 2; a half mirror 9 provided so as to enable insertion into and removal from an optical path between the photographic optical system and the imaging element; switching means for switching a first state in which the half mirror is on the optical path between the photographic optical system and the imaging element and a second state in which the half mirror is saved from the optical path between the photographic optical system and the imaging element; and reading range switching means for switching a first reading range in which reading is made from the imaging element when the half mirror is in the first state and a second reading range in which reading is made from the imaging element when the half mirror is in the second state according to the first state and the second state of the half mirror.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an imaging apparatus and an imaging system, and more particularly to an imaging apparatus and an imaging system provided with a half mirror.

  In a conventional single-lens reflex camera equipped with a half mirror, the half mirror is inserted into the optical path of the photographic light beam, and part of the light is bent at the top of the camera so that the photographed image can be confirmed via the finder optical system. An image pickup apparatus has been proposed in which the light passes through a half mirror and focus detection is performed in the image pickup element. When focus detection is performed using light that has passed through the half mirror, the half mirror is retracted from the optical path of the imaging light beam at the time of imaging, and therefore the optical path changes at the time of imaging and at the time of focus detection.

  For example, in Patent Document 1, in a single-lens reflex digital camera equipped with a half mirror, when the half mirror is at the optical path insertion position, the lens is moved to the in-focus position based on the subject light flux incident on the image sensor via the half mirror. In addition, before moving the half mirror to the retracted position, the photographing lens is moved by the amount of change in the optical path length by the half mirror, and then photographing is known.

  In Patent Document 2, whether the half mirror is refracted by the half mirror when the half mirror is at the first position where the half mirror advances on the optical path between the imaging optical system and the imaging element and when the half mirror is at the second position where the half mirror is retracted from the optical path. Since the incident position of the incident light with respect to the image sensor is shifted by, for example, several pixels to several tens of pixels, the position of the image sensor at the time of image capturing by the image sensor is changed by the difference. It is known to change between the first state and the second state.

JP 2000-32323 A JP 2013-167855 A

  However, in the conventional technique disclosed in Patent Document 1 described above, the photographing direction can be corrected by moving the photographing lens by the amount of change in the optical path length of the half mirror, but the refraction of the half mirror can be performed. As a result, the position where the photographed image is formed changes within the surface of the image sensor, so that the subject image to be photographed and the distance measurement target image for distance measurement are different.

  Further, in Patent Document 2, by changing the position of the image sensor, the incident position of the incident light in the imaging surface when the half mirror advances and retracts on the optical path can be corrected. Since the mechanism moves mechanically, the mechanism becomes large, and a space for arranging the mechanism becomes necessary.

In order to achieve the above object, the present invention provides:
An image sensor for imaging a subject image formed by the imaging optical system;
A half mirror provided in an optical path between the imaging optical system and the image sensor so as to be removable
A first state in which the half mirror is on an optical path between the imaging optical system and the imaging element; and a second state in which the half mirror is retracted from an optical path between the imaging optical system and the imaging element Switching means for switching between,
A first reading range for reading out of the image sensor in the first state;
A second reading range for reading out of the image sensor in the second state;
Read range switching means between the first read range and the second read range according to the first state and the second state of the half mirror
It is provided with.

  According to the present invention, it is possible to provide an imaging apparatus that always uses the same image information as a captured image regardless of whether the main mirror is on the optical path of the imaging optical system.

1 is a schematic configuration diagram of an imaging apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram of a pixel arrangement in the first embodiment. FIG. 2 is a schematic plan view and a schematic cross-sectional view of a pixel according to the first embodiment. Schematic of the pixel and pupil division in a 1st embodiment. Schematic explanatory drawing of the image element and pupil division in a 1st embodiment. FIG. 3 is a distance measurement point arrangement diagram according to the embodiment of the present invention. FIG. 6 is a diagram illustrating a distance calculation calculation range division in the live view mode according to the first embodiment. Explanatory drawing which shows the ranging calculation range at the time of the range finding calculation range at the time of the optical finder mode and live view mode in 1st Embodiment. FIG. 3 is a schematic cross-sectional view schematically showing a state where a light beam on a photographing optical axis in the first embodiment is transmitted through a half mirror. 3 is a schematic flowchart illustrating an example of the operation of the imaging apparatus according to the first embodiment. The schematic sectional drawing which shows typically a mode that the light beam in 2nd Embodiment permeate | transmits a half mirror. FIG. 7 is a diagram of arrangement of distance measuring points in the second embodiment. FIG. 10 is a schematic explanatory diagram illustrating a deviation amount between a distance calculation calculation range division in a live view mode and a distance measurement calculation range division in an optical viewfinder mode according to the second embodiment. Schematic of the pixel arrangement in the third embodiment. The front view and sectional drawing which show arrangement | positioning of the imaging pixel of the image pick-up element in 3rd Embodiment. The front view and sectional drawing which show arrangement | positioning of the focus detection pixel of the image pick-up element in 3rd Embodiment. FIG. 10 is a schematic explanatory diagram illustrating a shift amount between a focus detection pixel group in a live view mode and a focus detection pixel group in an optical viewfinder mode according to a third embodiment. Explanatory drawing which shows the photometry range division | segmentation at the time of the distance measurement point arrangement | positioning and live view mode in 4th Embodiment. Schematic explanatory drawing which shows the gap | deviation amount of the photometry range division | segmentation at the time of live view mode in 4th Embodiment, and the photometry range division | segmentation at the time of optical finder mode.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an imaging apparatus according to an embodiment of the present invention.

[Example 1]
Hereinafter, with reference to FIG. 1, a reading range switching unit that switches the reading range of the imaging apparatus according to the state of the half mirror according to the first embodiment of the present invention will be described. In FIG. 1, a photographic optical system 2, all or a part of the lenses constituting the photographic optical system are moved inside a detachable photographic lens 1, and a focus adjusting means 3 for adjusting the focus, and the photographic lens 1. A lens control means 4 for controlling and a lens storage means 5 such as a ROM are included.

  The camera body 8 includes a main mirror 9, an imaging device 14 as a photographing medium, camera control means 16, camera calculation means 17, and camera storage means 18. The taking lens 1 and the camera body 8 have a contact point 19, and when they are attached to each other, information is communicated and power is supplied through the contact point 19. La is the optical axis of the taking lens 1. The light beam incident along the optical axis La reaches the main mirror 9 having a semi-transmissive portion, and is divided into two light beams of reflected light and transmitted light.

  On the reflected light side, a transmissive liquid crystal 11, a pentaprism 12, and an eyepiece 13 for displaying information such as a focusing screen 10, a distance measuring point, and the like are arranged along the optical axis La. These members are formed on the focusing screen 10. A finder system for visualizing the finder image formed is configured.

  On the other hand, the light flux on the transmitted light side of the main mirror 9 enters the image sensor 14. The main mirror 9 is movable to a first position that advances into the photographing optical path between the photographing optical system 2 and the image sensor 14 and a second position that retreats from the photographing optical path between the photographing optical system 2 and the image sensor 14. It is provided to become.

  When the main mirror 9 is at the first position in the imaging optical path, the main mirror 9 separates the incident light beam into a reflected light beam and a transmitted light beam, guides the reflected light beam to the viewfinder system, and transmits the transmitted light beam to the image sensor 14. The photographer can confirm the subject image with the eyepiece 13. This is called an optical finder mode. In the case of the second position where the main mirror 9 is retracted out of the imaging optical path, the imaging light flux is guided to the imaging element 14 without being transmitted or reflected, and the subject image obtained by the imaging element 14 can be confirmed on the liquid crystal screen 15. it can. This is called a live view mode.

  In the case of the optical viewfinder mode, when shooting, the main mirror 9 is moved to the second position where the main mirror 9 is retracted out of the imaging optical path, and shooting is performed with the imaging device 14. The imaging element 14 has a focus detection pixel that photoelectrically converts two images formed by a light beam divided into two by a pupil division function described later in the photographing lens 1.

  In the case of the optical finder mode, the main mirror 9 is in the imaging optical path, so that the focus detection is performed by the focus detection pixel of the image sensor 14 using the light beam transmitted through the main mirror 9.

  On the other hand, in the live view mode, since the main mirror 9 is retracted out of the photographing optical path, focus detection is performed by the focus detection pixel of the image sensor 14 using the incident light beam itself from the photographing lens.

  FIG. 2 is a schematic diagram of an arrangement of focus detection pixels as imaging pixels of the image sensor 14 in the present embodiment. The schematic diagram of the image sensor in FIG. 2 shows a pixel (imaging pixel) array of the image sensor 14 in a range of 4 columns × 4 rows and a focus detection pixel array in a range of 8 columns × 4 rows. .

  In the present embodiment, the pixel group 200 of 2 columns × 2 rows shown in FIG. 2 has a blue spectral sensitivity of the pixel 200R having a red spectral sensitivity at the upper left, the pixel 200G having a green spectral sensitivity at the upper right and the lower left. The pixel 200 </ b> B that is included is arranged at the lower right. Further, each pixel includes a first focus detection pixel 201 and a second focus detection pixel 202 arranged in 2 columns × 1 row. The imaging device 14 obtains a captured image by arranging a large number of pixel groups 200 shown in FIG. 2 on the surface.

  FIG. 3 shows a plan view (a) of one image pickup pixel of the image pickup device viewed from the light receiving surface side and a cross-sectional view (b) of the image pickup pixel. As shown in FIG. 3B, in the pixel 200G of this embodiment, a microlens 305 for condensing incident light is formed on the light receiving side of each pixel, divided into two in the x direction and I in the y direction. A divided photoelectric conversion unit 301 and photoelectric conversion unit 302 are formed. The photoelectric conversion units 301 and 302 correspond to the first focus detection pixel 201 and the second focus detection pixel 202, respectively.

  In each pixel, a color filter 306 is formed between the microlens 305 and the photoelectric conversion unit 301 and the photoelectric conversion unit 302. Further, as necessary, the spectral transmittance of the color filter may be changed for each sub-pixel, or the color filter may be omitted.

  Light incident on the pixel 200 </ b> G illustrated in FIG. 3 is collected by the microlens 305, dispersed by the color filter 306, and then received by the photoelectric conversion unit 301 and the photoelectric conversion unit 302. FIG. 4 is a schematic explanatory diagram showing the correspondence between the pixel structure of this embodiment shown in FIG. 3 and pupil division. FIG. 4 shows a sectional view of the pixel structure of the present embodiment shown in FIG. 3A as viewed from the + y side and an exit pupil plane of the imaging optical system.

  In FIG. 4, in order to correspond to the coordinate axis of the exit pupil plane, the x-axis and y-axis of the cross-sectional view are inverted with respect to FIG. In FIG. 4, the first pupil partial region 501 of the first focus detection pixel 201 is generally conjugated with the light receiving surface of the photoelectric conversion unit 301 whose center of gravity is decentered in the −x direction and the microlens. , The first focus detection pixel 201 represents a pupil region that can receive light. The first pupil partial region 501 of the first focus detection pixel 201 has an eccentric center of gravity on the + X side on the pupil plane.

  In FIG. 4, the second pupil partial region 502 of the second focus detection pixel 202 is generally conjugated with the light receiving surface of the photoelectric conversion unit 302 whose center of gravity is decentered in the + x direction and the microlens. A pupil region that can be received by the second focus detection pixel 202 is shown. The center of gravity of the second pupil partial region 502 of the second focus detection pixel 202 is eccentric to the −X side on the pupil plane. In FIG. 4, the pupil region 500 can receive light in the entire pixel 200 </ b> G when the photoelectric conversion unit 301 and the photoelectric conversion unit 302 (first focus detection pixel 201 and second focus detection pixel 202) are all combined. This is the pupil area.

  FIG. 5 is a schematic diagram showing the correspondence between the image sensor of this embodiment and pupil division. Light beams that have passed through different pupil partial areas of the first pupil partial area 501 and the second pupil partial area 502 are incident on each pixel of the image sensor at different angles, and are used for first focus detection divided into 2 × 1. Light is received by the pixel 201 and the second focus detection pixel 202.

  In the present embodiment, the pupil region is divided into two pupils in the horizontal direction. If necessary, pupil division may be performed in the vertical direction.

  The imaging device of the present embodiment includes a first focus detection pixel that receives a light beam passing through the first pupil partial region of the imaging optical system, and a second pupil partial region of the imaging optical system different from the first pupil partial region. A plurality of second focus detection pixels that receive a light beam passing through the lens are arranged. In the imaging device of the present embodiment, a plurality of imaging pixels that receive a light beam passing through a pupil region in which the first pupil partial region and the second pupil partial region of the imaging optical system are combined are arranged.

  In the imaging device of the present embodiment, each imaging pixel is composed of a first focus detection pixel and a second focus detection pixel. If necessary, the imaging pixel, the first focus detection pixel, and the second focus detection pixel are configured as separate pixels, and the first focus detection pixel and the second focus detection pixel are included in a part of the imaging pixel array. A configuration in which pixels are partially arranged may be employed.

  In the present embodiment, a first focus signal is generated by collecting the light reception signals of the first focus detection pixels 201 of each pixel of the image sensor, and the second light reception signals of the second focus detection pixels 202 of each pixel are collected. A focus signal is generated to perform focus detection. Further, by adding the signals of the first focus detection pixel 201 and the second focus detection pixel 202 for each pixel of the image pickup device, an image pickup signal (captured image) having a resolution of N effective pixels is generated.

  In this embodiment, focus detection is performed by performing known imaging plane phase difference AF using the first focus detection pixel group 201 and the second focus detection pixel group 202. Since focus detection pixels are arranged on the entire surface of the image sensor, phase difference AF can be performed on the entire surface of the image sensor.

  However, since the processing of the image information becomes complicated, in this embodiment, several blocks of locations where focus detection is performed in the image sensor are arranged, and the information on the first focus detection pixel 201 and the second focus detection are arranged for each block. Focus detection is performed using the information of the pixel for use 202. In addition, FIG. 6 shows a diagram in which a distance measuring point location used in this embodiment is projected on a captured image. FIG. 7 shows the division of the focus detection block of the image sensor in the live view mode.

  In the live view mode, the focus detection location in FIG. 6 is displayed on the rear liquid crystal. The photographer automatically or arbitrarily selects a position for focus detection from the distance measuring points shown in FIG. Corresponding to the selected distance measuring point shown in FIG. 6, focus detection is performed using information on the focus detection pixels of the focus detection block of the image sensor shown in FIG.

  On the other hand, in the optical finder mode, the main mirror 9 enters the imaging optical path, separates the incident light beam into a reflected light beam and a transmitted light beam, guides the reflected light beam to the finder system, and guides the transmitted light beam to the image sensor.

  In the optical viewfinder mode, the focus detection location on the captured image in FIG. 6 is displayed on the transmissive liquid crystal panel, and the photographer can check the focus detection location through the viewfinder. In the case of the optical finder mode, the light beam that has passed through the main mirror 9 reaches the image sensor 14, and therefore the information on the focus detection pixel 201 on the image sensor 14 and the second light beam are transmitted through the main mirror 9. Focus detection can be performed using information of the focus detection pixel 202.

  At this time, since the light beam transmitted through the main mirror 9 is refracted by the main mirror, if focus detection is performed by dividing the focus detection block shown in FIG. 7 as in the live view mode, the focus on the imaging pixel shown in FIG. Focus detection will be performed at a position different from the detection location.

  Therefore, in the present embodiment, in the case of the optical finder mode, the division of the focus detection block is arranged by shifting the position by the amount of refraction of the main mirror 9.

  FIG. 8 shows a focus detection block in the case of the optical finder mode. In FIG. 8, reference numeral 801 indicated by a solid line is the division of the focus detection block in the optical finder mode. In FIG. 8, 802 indicated by a dotted line is a division of the focus detection block in the live view mode, which is the same division as in FIG.

  FIG. 9 is a schematic diagram schematically showing a state in which light rays incident along the optical axis of the photographing lens are transmitted through the main mirror 9 when the main mirror 9 is in the imaging optical path. In FIG. 9, the inclination angle of the main mirror 9 is denoted by θ1, the incident angle of light rays incident along the lens optical axis La on the main mirror 9 is denoted by θ2, and the refraction angle of the light rays is denoted by θ3.

  When the thickness of the main mirror 9 is d and the refractive index of the substrate of the main mirror 9 is n, the main mirror 9 is retracted from the imaging optical path and the main mirror 9 is disposed in the imaging optical path. The amount of deviation Δy of the light incident along the lens optical axis La is

It is represented by

  In FIG. 8, a focus detection block division 801 in the case of the optical viewfinder mode indicated by a solid line is a focus detection block division 802 in the case of the live view mode indicated by a dotted line, which is a position shifted by Δy shown in Equation 1. It is divided by.

  In this embodiment, the angle of the main mirror is 45 degrees, the thickness of the main mirror 9 is 1.5 mm, and the refractive index of the main mirror 9 is 1.53. Therefore, Δy is 0.508 mm.

  FIG. 10 is a schematic flowchart of the present embodiment. When the live view mode or the optical viewfinder mode is selected by a button arranged on the camera body (step 1003), in the live view mode, it is confirmed whether the main mirror 9 is up (step 1004). Here, the mirror-up indicates a state in which the main mirror 9 is retracted from the photographing optical path between the photographing optical system 2 and the image sensor 14. If the mirror is not raised, the mirror is raised (step 1005).

  If the live view mode is selected, the division of the range in which the ranging calculation is performed is set to the live view block division (step 1006). On the other hand, when the optical finder mode is selected, the division of the range in which the distance measurement calculation is performed is set to the block division of the optical finder mode (step 1007).

  Thereafter, when the shutter button is half-pressed (step 1008), it is confirmed whether the distance measuring point selection is automatic or arbitrary (step 1009). When ranging point selection is automatic, ranging calculation is performed in all blocks corresponding to all ranging points (step 1010), and ranging points are determined (step 1011).

  As a method of determining a distance measuring point in step 1011, for example, a distance measurement calculation is performed in all blocks, and the object that is considered to be present at the position closest to the imaging device within the driveable range of the focus lens of the photographing lens. Determine the distance point.

  On the other hand, if the distance measurement point selection is arbitrary, distance measurement calculation is performed in the block corresponding to the selected distance measurement point (step 1012). After the calculation, the focus lens of the photographic lens is driven based on the calculation result (step 1013).

  Thereafter, when the shutter button is fully pressed (step 1014), the state of the main mirror is confirmed (step 1015). If the main mirror is not up, it is retracted out of the imaging optical path of the main mirror (step 1016). . Imaging is performed with the main mirror retracted from the imaging optical path (step 1017).

[Example 2]
Hereinafter, with reference to FIG. 11, a reading range switching means for switching the reading range of the imaging apparatus according to the state of the half mirror according to the second embodiment of the present invention will be described.

  FIG. 11 is a schematic diagram schematically illustrating a state in which a light beam incident on the position of the imaging sensor y1 is transmitted through the main mirror 9 when the main mirror 9 is in the imaging optical path when the main mirror 9 is retracted from the imaging optical path. It is.

  In FIG. 11, 1101 denotes an exit pupil of the photographing lens, and 14 denotes the image sensor shown in FIG. Reference numeral 1103 indicated by a dotted line represents a principal ray of a light ray incident on the position y1 of the image pickup device when the main mirror 9 is retracted from the image pickup optical path. Reference numeral 1102 indicated by a solid line indicates that the main ray of the light beam incident on the position y1 of the image pickup element passes through the main mirror 9 when the main mirror is in the image pickup optical path when the main mirror 9 is retracted from the image pickup optical path. The situation is shown schematically.

  Let P be the distance from the image sensor 14 to the exit pupil position of the photographic lens, and y1 be the coordinates in the y direction of the image sensor that the light rays reach when the main mirror 9 is retracted from the imaging optical path. Further, the inclination amount of the main mirror 9 from the vertical direction is θ1a, and when the main mirror 9 is retracted out of the imaging optical path, the angle of the ray incident on the y1 position of the image sensor with respect to the optical axis of the principal ray is θ2a. The refraction angle of the light beam is θ3a. At this time, the position Δy1 at which the light beam reaching the y1 of the imaging sensor to which the light beam reaches when the main mirror 9 is retracted from the imaging optical path is shifted by the main mirror entering the imaging optical path is

It is represented by

  Therefore, the amount of deviation of the light beam depending on whether or not the main mirror 9 is in the imaging optical path varies depending on the exit pupil position P of the imaging lens and the position y1 of the imaging element.

  In the present embodiment, a distance measurement calculation is performed at a correct location by changing the amount of change in the amount of light deviation Δy1 depending on the exit pupil position P of the photographing lens and the position y1 of the image sensor for each lens.

  A portion written with a solid line in FIG. 12 indicates a distance measuring point of this embodiment. FIG. 13 shows the division of the focus detection block.

  FIG. 13 shows the division of the focus detection block when the block division written with a dotted line is in the live view mode. Further, FIG. 13 shows the division of the focus detection block when the block division written with a solid line is in the optical finder mode.

  Of the distance measurement points shown in FIG. 12, the shift amount of the focus detection block division corresponding to the distance measurement point group 1201 is indicated by Δy 132 in FIG. Further, among the distance measuring points shown in FIG. 12, the shift amount of the focus detection block corresponding to the distance measuring point group indicated by 1202 is indicated by Δy 131 in FIG. Further, among the distance measuring points shown in FIG. 12, the shift amount of the focus detection block corresponding to the distance measuring point group shown by 1303 is indicated by Δy 133 in FIG.

  In this embodiment, the angle of the main mirror is 45 degrees, the thickness of the main mirror 9 is 1.5 mm, the refractive index of the main mirror 9 is 1.53, and the image height in the y direction of the distance measuring point group 1201 shown in FIG. 12 is 9.6 mm. The image height in the y direction of the distance measuring point group 1203 is -9.6 mm. Therefore, when a photographing lens having an exit pupil position P of 70 mm is attached, Δy 131 is 0.508 mm, Δy 132 is 0.648 mm, and Δy 133 is 0.396 mm.

  In this embodiment, the position of dividing the focus detection block in the optical finder mode is changed according to the position of the exit pupil of the photographing lens. The exit pupil position of the photographic lens 2 is stored in the lens storage means 5.

  The camera body 8 acquires the exit pupil position of the taking lens 2 stored in the lens storage means 5 through the contact point 19. The focus detection block in the optical finder mode is calculated by calculating the deviation amount of the focus detection block in the optical finder mode from the acquired exit pupil position and the image height of each ranging point stored in the camera storage means. Change the division position of.

[Example 3]
Hereinafter, with reference to FIG. 14, a reading range switching means for switching the reading range of the imaging apparatus according to the state of the half mirror according to the third embodiment of the present invention will be described.

  An image element used in Example 3 is shown in FIG. The imaging element 14 shown in FIG. 1 has a focus detection pixel group that photoelectrically converts two images formed by a light beam divided into two by a pupil division function described later in the photographing lens 1.

  In this embodiment, a correlation operation is performed on two image signals from the focus detection pixel group on the image sensor 14 to calculate a focus detection pixel phase difference between the two image signals. Then, the defocus amount of the imaging lens 1 is calculated based on the focus detection pixel phase difference, and the focus lens is driven via the focus adjustment unit 3 based on the defocus amount.

  A photographing pixel group and a focus detection pixel group of the image sensor 14 will be described with reference to FIGS. 15 and 16. FIG. 15A shows a 2 × 2 photographing pixel group.

  In this embodiment, a two-dimensional single-plate CMOS color image sensor in which primary color filters of R (Red), G (Green), and B (Blue) are Bayer arranged is used as the image sensor 14. In the Bayer array, G pixels are arranged diagonally among 4 pixels of 2 rows × 2 columns, and R and B pixels are arranged as the other two pixels. This pixel arrangement of 2 rows × 2 columns is repeated over the entire image sensor 14.

A cross-sectional view AA of the imaging pixel shown in FIG. 15A is shown in FIG. ML is a microlens disposed in front of each pixel, CF _R color filters R, CF _G is G color filter, PD denotes a photoelectric conversion unit of the CMOS sensor schematically. CL is a wiring layer for forming signal lines for transmitting various signals in the CMOS sensor. TL schematically shows the photographing optical system. The microlens ML and the photoelectric conversion unit PD of the image sensor are configured to capture the light beam that has passed through the photographing optical system TL as effectively as possible.

  That is, the exit pupil EP of the photographing optical system TL and the photoelectric conversion unit PD are conjugated with each other by the microlens ML, and the effective area of the photoelectric conversion unit PD is set large. FIG. 15B shows the incident light beam on the R pixel, but the light beam that has passed through the photographing optical system TL is also incident on the G pixel and the B pixel.

  Therefore, the diameter of the exit pupil EP corresponding to each of the RGB imaging pixels is increased, and the light flux from the subject can be taken in efficiently. Thereby, it is possible to improve the S / N of the imaging signal used for generating the live view image and the recording image.

  FIG. 16A is a plan view of a pixel group of 2 rows × 2 columns including focus detection pixels that perform pupil division of the imaging optical system in the horizontal direction (lateral direction) in FIG. . The G pixel outputs a G imaging signal that is a main component of luminance information. Since human image recognition characteristics are sensitive to luminance information, image quality degradation is likely to be noticed when G pixels are missing. On the contrary, the R and B pixels are pixels that mainly acquire color information. However, since humans are insensitive to color information, even if there is some deficiency in the pixels that acquire color information, image quality deterioration is not easily recognized. For this reason, in this embodiment, among the 2 rows × 2 columns image sensor shown in FIG. 16A, the G pixel is left as an image sensor, and a part of the R and B pixels are replaced with focus detection pixels. Yes.

  In FIG. 16A, focus detection pixels are denoted by SA and SB. A cross section BB of the focus detection pixel shown in FIG. 16A is shown in FIG. The microlens ML and the photoelectric conversion unit PD in the focus detection pixel are the same as the microlens ML and the photoelectric conversion unit PD of the imaging pixel illustrated in FIG.

In this embodiment, since the image signal from the focus detection pixel is not used to generate a live view image or a recording image, the focus detection pixel has a transparent film CF _W (White) instead of a color filter. Has been placed.

  In addition, in order to give the focus detection pixel a pupil division function, openings (hereinafter referred to as aperture openings) OPHA and OPHB of the wiring layer CL are arranged in one direction with respect to the center line of the microlens ML.

  Specifically, in the focus detection pixel SA, the aperture opening OPHA is arranged to be biased to the right side in FIG. .

  On the other hand, in the focus detection pixel SB, the aperture opening OPHA is arranged to be deviated to the left in FIG. 13, and receives the light beam that has passed through the exit pupil region EPHB in the exit pupil of the photographing optical system TL.

  Thereby, the focus detection pixels SA and SB can receive two different light beams of the same subject and photoelectrically convert them. A plurality of focus detection pixels SA are regularly arranged in the vertical direction, and one of the two images formed on these focus detection pixel groups SA is defined as an A image. A plurality of focus detection pixels SB are regularly arranged in the vertical direction, and one of the two images formed on the focus detection pixel group SB is a B image. A and B images are photoelectrically converted by the focus detection pixels SA and SB, and a phase difference (hereinafter referred to as focus detection pixel phase difference) as a shift amount (including direction) of an image signal output from the focus detection pixels SA and SB. Calculated).

  Based on the focus detection pixel phase difference, the defocus amount (including the direction) of the imaging lens 1 can be obtained. In the case of detecting the phase difference between the A image and the B image in the horizontal direction (lateral direction), the aperture opening OPHA of the focus detection pixel SA and the aperture opening OHPB of the focus detection pixel SB are arranged so as to be biased left and right. do it. Further, when detecting the phase difference between the A image and the B image in the vertical direction (vertical direction), the aperture opening OPHA of the focus detection pixel SA and the aperture opening OHPB of the focus detection pixel SB are respectively biased up and down. What is necessary is just to arrange.

  FIG. 14 and FIG. 17 show examples of arrangement of the photographing pixel group and the focus detection pixel group on the image sensor. In consideration of the fact that the focus detection pixel groups SA and SB are not used for image generation, in this embodiment, the focus detection pixels SA and SB are discretely arranged at intervals in the horizontal direction. In addition, it is desirable that the focus detection pixel is not arranged at the position of the G pixel so that pixel deficiency (that is, image degradation) on the image due to the focus detection pixels SA and SB is less noticeable.

  In the present embodiment, in the live view mode in which the main mirror 9 is retracted from the imaging optical path, focus detection is performed using the focus detection pixel group 172 in FIG. Further, in the optical finder mode in which the main mirror 9 is on the imaging optical path, focus detection is performed using the focus detection pixel group 173 in FIG. In the case of the optical viewfinder mode, the light beam transmitted through the main mirror 9 is refracted by the main mirror.

  In this case, if focus detection is performed by the focus detection pixel group 172 shown in FIG. 17 that is the same as the live view mode, focus detection is performed at a position different from the focus detection location on the imaging pixel shown in FIG.

  Therefore, it is necessary to perform focus detection at a position shifted by the amount of refraction of the light beam by the main mirror 9. The amount by which the light beam is refracted by the main mirror 9 and the light beam is shifted is obtained by Equation 1.

In this embodiment, Δy 171 in FIG. 17 corresponds to the amount by which the light beam is not refracted by the main mirror 9.
A focus detection pixel is also arranged at a position shifted by Δy171.

  In this embodiment, the angle of the main mirror is 45 degrees, the thickness of the main mirror 9 is 1.5 mm, and the refractive index of the main mirror 9 is 1.53. Therefore, Δy171 is 0.508 mm. Therefore, focus detection can be performed on the subject target image to be photographed regardless of the position of the main mirror 9.

[Example 4]
Hereinafter, with reference to FIG. 18, a reading range switching means for switching the reading range of the imaging device according to the state of the half mirror according to the third embodiment of the present invention will be described.

  In the present embodiment, the implementation of the present invention in the case of performing photometry for imaging based on the image information of the image element 14 in FIG. 1 will be described. In the present embodiment, in the imaging camera of FIG. 1, photometry is performed based on image information of the imaging element 14 to adjust exposure for shooting.

  In the live view mode in which the main mirror 9 is retracted outside the imaging optical path, the imaging optical path itself is incident on the imaging element 14. In the live view mode, the image sensor 14 is divided into blocks shown in FIG. 18 to acquire the amount of charge accumulated for each block.

  In FIG. 18, block division of the photometric calculation range in the live view mode is indicated by a dotted line 181. In FIG. 18, a solid line 182 indicates a focus detection location on the captured image, which is the same as the distance measurement point arrangement shown in FIG.

  The photometry image sensor block division 181 shown in FIG. 18 corresponds to the distance measuring point arrangement 182, and the center of each block of the photometry image sensor block division 181 is substantially the same as the center of the distance measurement point arrangement 182. It has become a division.

  On the other hand, in the optical viewfinder mode, since the main mirror 9 is in the imaging optical path, the incident light is refracted and forms an image at a position different from that in the live view mode. Therefore, it is necessary to shift the center of the distance measuring point shown in FIG. 6 and the block of the image sensor division when performing the photometry by the refraction of the main mirror 9 from the arrangement of the flock division in the live view mode.

  FIG. 19 shows a photometric block division in the live view mode used in the present embodiment by a dotted line 192, and a photometric block division used in the optical viewfinder mode by a solid line 191.

  The photometric block division 191 in the optical fander mode performs block division at a position shifted downward from the photometric block division 192 in the live view mode due to the influence of refraction by the main mirror 9.

  The amount of deviation between the photometric block division 191 in the optical fander mode and the photometric block division 192 in the live view mode is indicated by Δy19 in FIG. Δy19 can be calculated by the same equation as Δy shown in Equation 1 of Example 1.

  In this embodiment, the angle of the main mirror is 45 degrees, the thickness of the main mirror 9 is 1.5 mm, and the refractive index of the main mirror 9 is 1.53. Therefore, Δy19 is 0.508 mm.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 1 Shooting lens 2 Shooting optical system 3 Focus adjustment means 4 Lens control first stage 5 Lens storage means 8 Camera main body 9 Main mirror 10 Focus plate 11 Transmission type liquid crystal 12 Pentaprism 13 Eyepiece 14 Imaging element 15 Back surface liquid crystal 16 Camera control means 17 Camera Calculation means 18 Camera storage means 19 Contact

Claims (6)

An image sensor for imaging a subject image formed by the imaging optical system;
A half mirror provided in an optical path between the imaging optical system and the image sensor so as to be removable
A first state in which the half mirror is on an optical path between the imaging optical system and the imaging element; and a second state in which the half mirror is retracted from an optical path between the imaging optical system and the imaging element Switching means for switching between,
A first reading range for reading out of the image sensor in the first state;
A second reading range for reading out of the image sensor in the second state;
Read range switching means between the first read range and the second read range according to the first state and the second state of the half mirror
An imaging apparatus comprising: The imaging apparatus according to claim 1, wherein the readout range is a distance measurement calculation range in which focus detection is performed. The imaging apparatus according to claim 1, wherein the readout range is a photometric calculation range for performing photometry. The imaging apparatus according to claim 1, wherein the first readout range is changed according to lens information. The imaging apparatus according to claim 4, wherein the lens information is a position of an exit pupil of a photographing optical system. The imaging apparatus according to claim 1, further comprising a lens information storage unit that stores the lens information.