JP2014228724A - Imaging device and intermediate adapter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform measurement of an aberration even when an F-number of an image formation optical system is smaller than an F-number of a microlens.SOLUTION: An imaging device 1 comprises: a plurality of microlenses that have a flux of light transmitting an image formation optical system 11 two-dimensionally arranged so as to be incident; a light reception element array 32 that corresponds to the plurality of microlenses, respectively, and has a plurality of light reception elements arranged on a rear side of the microlens; shielding means 33 that is capable of changing over between a shield state where a cross sectional surface of the flux of light is limited to a shape excentric to an optical axis L of the image formation optical system 11 by shielding a part of the flux of light transmitting the image formation optical system 11 and a passing-through state where the flux of light transmitting the image formation optical system 11 is not shield, but is caused to pass through; and aberration detection means 23 that detects aberration information relating to an aberration of the image formation optical system 11 on the basis of an output signal of the light reception element array 32 corresponding to the flux of light transmitting the image formation optical system 11 and having the part thereof shielded by the shielding means 33.

Description

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

  2. Description of the Related Art Conventionally, there has been known an imaging apparatus that corrects a focus detection result or a captured image based on aberration characteristics of an imaging optical system to reduce the influence of aberration. In addition, as a measuring device for measuring the aberration characteristics of the imaging optical system, a microlens array in which a plurality of microlenses are arranged, and a plurality of light receiving elements are provided for each of the plurality of microlenses to receive light beams. A measuring apparatus provided with an element array is known (see Patent Document 1). In this measuring apparatus, the light receiving element array receives light through different partial pupils of the imaging optical system to be measured, and measures aberration based on the received light signal.

JP 2010-60362 A

  By the way, in the conventional measuring apparatus described above, when the imaging optical system is a lens brighter than the microlens, that is, when the F value of the imaging optical system is smaller than the F value of the microlens, the adjacent microlens Crosstalk of light beams that have passed through the microlens occurs between the two. Therefore, a normal light reception signal cannot be obtained, and there is a problem that the aberration of the imaging optical system cannot be measured.

(1) An image pickup apparatus according to the first aspect of the invention corresponds to each of a plurality of microlenses arranged two-dimensionally so that a light beam transmitted through an imaging optical system is incident thereon, and each of the plurality of microlenses. A light-receiving element array having a plurality of light-receiving elements arranged on the rear side of the microlens and a part of the light beam that has passed through the imaging optical system, thereby blocking the cross section of the light beam that has passed through the imaging optical system, Shielding means capable of switching between a shielding state in which the shape is deviated with respect to the optical axis of the imaging optical system and a passing state in which the light beam transmitted through the imaging optical system is allowed to pass without being shielded; Aberration information relating to the aberration of the imaging optical system is detected based on the output signal of the light receiving element array corresponding to the light beam that is transmitted through the F-number imaging optical system and partially shielded by the shielding means in the shielding state. And an aberration detection means. To.
(2) The intermediate adapter according to the ninth aspect of the invention corresponds to each of the plurality of microlenses arranged two-dimensionally so that the light beam transmitted through the imaging optical system is incident, and each of the plurality of microlenses. A light-receiving element array having a plurality of light-receiving elements arranged on the rear side of the microlens and a part of the light beam that has passed through the imaging optical system, thereby blocking the cross section of the light beam that has passed through the imaging optical system, Shielding means capable of switching between a shielding state in which the shape is deviated with respect to the optical axis of the imaging optical system and a passing state in which the light beam transmitted through the imaging optical system is allowed to pass without being shielded; Aberration information relating to the aberration of the imaging optical system is detected based on the output signal of the light receiving element array corresponding to the light beam that is transmitted through the F-number imaging optical system and partially shielded by the shielding means in the shielding state. An aberration detecting means. And features.

  According to the present invention, aberration can be measured even when the F value of the imaging optical system is smaller than the F value of the microlens.

It is a figure which shows the structure of the imaging device by the 1st Embodiment of this invention. It is a perspective view of a focus detection unit. It is a schematic diagram of an imaging optical system and a focus detection unit. It is a figure explaining a mask member. It is a figure explaining the to-be-photographed image formed in a sub imaging device. It is a figure which shows the structure of the imaging device by the 2nd Embodiment of this invention. It is a figure explaining the mask member in the modification 1. FIG. 11 is a diagram for describing a subject image formed on a sub image sensor in Modification 2.

(First embodiment)
FIG. 1 is a diagram showing a configuration of an imaging apparatus according to the first embodiment of the present invention. The imaging device 1 includes a camera body 20 and a lens barrel 10 that can be attached to and detached from the camera body 20 via a lens mount 9. The lens barrel 10 includes an imaging optical system 11 that forms a subject image on a predetermined planned focal plane, and a diaphragm 12 that adjusts the amount of light incident on the imaging optical system 11. In FIG. 1, the imaging optical system 11 is schematically shown as a single lens. However, the imaging optical system 11 actually includes a plurality of focusing lenses that adjust the focus state of the imaging optical system 11. It is made up of lenses.

  Further, a pellicle mirror 21 is provided on the optical axis L of the imaging optical system 11 in the camera body 20 to branch the subject light that has passed through the imaging optical system 11 in two directions. In the camera body 20, a main imaging element 22 and a focus detection unit 30 that capture a subject image formed by the imaging optical system 11 are further provided. The pellicle mirror 21 directs one of the branched subject light toward the main image sensor 22 and the other toward the focus detection unit 30. The focus detection unit 30 includes a microlens array 31 and a sub imaging element 32. The structure of the focus detection unit 30 will be described in detail later.

  The main image pickup device 22 is a solid-state image pickup device such as a CCD or a CMOS, for example, and is arranged such that its image pickup surface is positioned on the first planned focal plane 5a of the imaging optical system 11. On the other hand, the microlens array 31 included in the focus detection unit 30 is disposed in the vicinity of the second planned focal plane 5b (a plane conjugate with the first planned focal plane 5a) of the imaging optical system 11. Although not shown in FIG. 1, an infrared cut filter or the like is provided on the imaging surface of the main imaging element 22 and each front surface of the microlens array 31.

  Further, on the optical axis L of the imaging optical system 11 in the camera body 20, part of the subject light that has passed through the imaging optical system 11 is shielded between the pellicle mirror 21 and the imaging optical system 11. A mask member 33 is provided. The mask member 33 is, for example, a flat plate member having a thin thickness in the optical axis direction (x direction). A mask member driving device 34 that drives the mask member 33 is further provided in the camera body 20. The mask member 33 and the mask member driving device 34 will be described in detail later.

  The camera body 20 further includes an electronic viewfinder unit 40, an eyepiece lens 42, and a rear monitor 41 constituting a so-called electronic viewfinder (EVF). The electronic viewfinder unit 40 has a built-in display device such as a liquid crystal display, and can display an image captured by the main image sensor 22 and the sub image sensor 32 on the display device. The user visually recognizes an image or the like displayed on the display device through the eyepiece 42. In the following description, displaying an image, a character, or the like on the display device of the electronic viewfinder unit 40 is simply referred to as “display on the viewfinder”. The rear monitor 41 is a display device such as a liquid crystal display provided on the rear surface of the camera body 20, and can display an image or the like, similar to the electronic viewfinder unit 40.

  The camera body 20 further includes a control device 23 that controls each unit described above. The control device 23 is composed of a microprocessor and its peripheral circuits, and controls each unit described above by reading and executing a control program stored in advance in a storage medium (not shown) such as a flash memory. For example, the control device 23 displays image data of a subject image (a so-called through image) on the viewfinder or the rear monitor 41 based on the output of either the main image sensor 22 or the sub image sensor 32. Note that the control device 23 can also be configured by an electronic circuit having a function equivalent to this control program.

(Configuration of focus detection unit)
Next, details of the focus detection unit 30 will be described with reference to FIG. FIG. 2 is a perspective view of the focus detection unit 30. As shown in FIG. 2, these members are arranged in parallel in the focus detection unit 30 in the order of the microlens array 31 and the sub imaging element 32 as viewed from the pellicle mirror 21 side. The microlens array 31 has a plurality of microlenses 35 that are positive lenses. Each microlens 35 is formed in a shape obtained by dropping four sides from a circular spherical lens, and has a substantially square shape when viewed from the direction of the optical axis L. The plurality of microlenses 35 are provided on the surface of the microlens array 31 on the pellicle mirror 21 side so as to be inclined by 45 degrees from the two-dimensional square array.

  The sub imaging element 32 is arranged so that the imaging surface faces the microlens array 31. A substantially square light receiving element (photoelectric conversion element) is squarely arranged on the imaging surface of the sub imaging element 32, and the size of the imaging surface covers at least the entire imaging range of the main imaging element 22. It is. One light receiving element is formed to be smaller than one micro lens 35, and a plurality of light receiving elements are included in a range in which one micro lens 35 is vertically projected.

  The microlens array 31 shown in FIG. 2 is depicted as having 200 microlenses 35 for convenience, but actually has more microlenses 35. Similarly, the number of light receiving elements included in the sub imaging element 32 is actually larger than the number shown in FIG.

  Usually, the interval between the microlens array 31 and the sub-image pickup device 32 is determined so that the image pickup surface of the sub-image pickup device 32 is approximately in the vicinity of the focal position of each microlens 35 constituting the microlens array 31. FIG. And in FIG. 2, it is drawn wider than actual for description.

  Note that the microlens array 31 may be arranged such that the front main surface thereof coincides with the second planned focal plane 5b. However, if the front main surface of the microlens array 31 is made coincident with the second planned focal plane 5b, that portion becomes a dead zone when there is a contrast of the subject image between the microlenses 35. In the present embodiment, such a dead zone is avoided by shifting the front main surface of the microlens array 31 and the second planned focal plane 5b.

(Description of lens barrel types)
By the way, the lens barrel 10 that can be mounted on the lens mount 9 of the camera body 20 includes (1) whether or not the focus control of the camera body 20 can be controlled, and (2) the photographing F value (aperture) from the camera body 20. There are a plurality of types depending on whether (value) is controllable, (3) whether aberration information representing the aberration characteristics of the imaging optical system 11 can be acquired from the camera body 20, and the like. The control device 23 determines which type of lens barrel 10 the lens barrel 10 attached to the camera body 20 corresponds to, and changes the control content of the lens barrel 10. Hereinafter, the control content of the control device 23 in each type will be described.

(1) Whether focus lens drive control can be performed from the camera body 20 When the drive control of the focus lens can be performed from the camera body 20 side, the control device 23 performs so-called autofocus control. For example, after the operation mode of the camera body 20 is set to the still image shooting mode, when the user performs a predetermined shooting preparation operation such as half-pressing the release switch, the control device 23 uses the focus detection unit 30 to form the imaging optics. The focus of the system 11 is detected, and the focus lens is driven based on the detection result to adjust the focus.

  On the other hand, when the drive control of the focus lens cannot be performed from the camera body 20 side, the control device 23 displays information on the detection result on the viewfinder and the rear monitor 41 instead of the focus adjustment. For example, icons and indicators are displayed that indicate whether the subject is in focus, whether it is the front or rear pin, how much is out of focus, and the like.

(2) Whether or not the photographing F value can be controlled from the camera body 20 When the photographing F value can be controlled from the camera body 20 side, that is, the aperture diameter of the diaphragm 12 at the time of exposure can be controlled from the camera body 20 In this case, the control device 23 receives an input of the photographing F value by an operation member (not shown) provided in the camera body 20. Further, in various controls described later, when it is necessary to control the aperture diameter of the diaphragm 12, the control device 23 automatically controls the aperture diameter of the diaphragm 12.

  On the other hand, when the shooting F value cannot be controlled from the camera body 20 side, the shooting F value is set by an operation member (not shown) provided on the lens barrel 10 (for example, an aperture ring). When it is necessary to control the aperture diameter of the diaphragm 12 in various controls to be described later, the control device 23 displays a predetermined message on the viewfinder and the rear monitor 41, and operates the operation member to set the F value to a predetermined value. Prompt the user to set the value.

(3) Whether aberration information of the imaging optical system 11 can be acquired from the camera body 20 In the lens barrel 10, aberration information representing the aberration characteristics of the imaging optical system 11 can be transmitted to the camera body 20 Things exist. Such a lens barrel 10 includes, for example, a storage medium (not shown) in which aberration information is stored in advance. In response to an instruction from the camera body 20, the aberration information is read from the storage medium and transmitted to the camera body 20. . When this type of lens barrel 10 is mounted, the control device 23 receives the aberration information from the lens barrel 10 in advance, and this aberration information is not shown at least while the lens barrel 10 is mounted. It memorizes in the memory etc. At the time of focus detection, the aberration detection information is used to correct the focus detection result, thereby improving the focus detection accuracy.

  On the other hand, when the lens barrel 10 that cannot transmit aberration information to the camera body 20 is attached, an aberration measurement mode for measuring the aberration of the imaging optical system 11 can be set as the operation mode of the camera body 20. It becomes possible. The user sets this aberration measurement mode prior to shooting, measures the aberration of the imaging optical system 11 and prepares aberration information, so that the lens barrel 10 capable of transmitting aberration information is similar to the lens barrel 10 capable of transmitting aberration information. High-precision focus detection can be performed.

(Explanation of aberration calculation method)
Here, an aberration calculation method in the aberration measurement mode of the present embodiment will be described. FIG. 3 is a schematic diagram of the imaging optical system 11 and the focus detection unit 30. In FIG. 3, only the central portion of the focus detection unit 30 (near the optical axis L of the imaging optical system 11) is shown in an enlarged manner.

  As shown in FIG. 3A, the light beams from the partial pupils 13a to 13h on the imaging optical system 11 are incident on the microlenses 35n1 to 35n5, respectively, and are incident on the sub imaging element 32. Note that signals output from the light receiving elements that receive the light beams from the partial pupils 13a to 13h that have passed through the microlens 35n1 are denoted as a (1),..., H (1) in FIG. The output signals corresponding to the other microlenses 35n2 to 35n5 are also indicated in the same manner.

  Further, hereinafter, a signal sequence including a light reception signal by a light beam emitted from the partial pupil 13a is denoted as {a (i)} (i = 1, 2,...). Similarly, for the other partial pupils 13a to 13h, for example, a signal sequence including a light reception signal by a light beam that has passed through the partial pupil 13b is represented as {b (i)} (i = 1, 2,...).

  Of the luminous flux from the object point, the luminous flux incident on the partial pupils 13a to 13h of the imaging optical system 11 may be incident on the image plane at a position different from the light passing through the center of the exit pupil, that is, the principal ray. . The amount of deviation of the incident position on the image plane of the light beam that has passed through each of these partial pupils 13a to 13h from the incident position of the principal ray is lateral aberration. The distribution of lateral aberration can be converted to the distribution of longitudinal aberration targeted by the present invention by a known method. For example, the control device 23 measures the aberration with respect to the microlens 35 arranged in the region from the optical axis L (the center of the imaging range) to the right end of the imaging range in the imaging range. Each of the signal trains {a (i)} to {h (i)} by the light beams that have passed through the partial pupils 13a to 13h and read from the corresponding light receiving elements of the microlenses 35, and the optical axis L The image shift amounts Sa to Sh of the partial pupils 13a to 13h are respectively calculated from the reference signal sequence made up of the light reception signals by the light beams that have passed through the upper partial pupil. Hereinafter, a method of calculating the image shift amount Sa will be described by expressing the above reference signal sequence as {x (i)}.

First, the control device 23 calculates the correlation amount C (N) of the signal sequences {a (i)} and {x (i)} by the following equation (1).
C (N) = Σ | a (i) −x (j) | (1)

In the above equation (1), j−i = N, and N is the number of shifts. Further, Σ represents a total calculation of a predetermined range related to i. Next, the control device 23 obtains a precise shift amount E by the following equations (2) and (3) from the correlation amount C (N) obtained discretely by the above equation (1). Here, the minimum value of the correlation amount C (N) is C0, and the shift amount N at that time is N0. The correlation amount at the shift amount (N0-1) is Cr, and the correlation amount at the shift amount (N0 + 1) is Cf. The control device 23 obtains the final image shift amount Sa by the following equation (4).
DL = (Cr−Cf) / 2 (2)
E = max {(Cf−C0), (Cr−C0)} (3)
Sa = N0 + DL / E (4)
The control device 23 calculates image shift amounts Sb to Sh corresponding to the partial pupils 13b to 13h, respectively, in the same procedure. The control device 23 treats the image shift amounts Sa to Sh as aberration information.

  By the way, when the imaging optical system 11 is a brighter lens than the microlens 35 (F value of the imaging optical system 11 is smaller than the F value of the microlens 35), sub-imaging is performed between the adjacent microlenses 35. The light beams incident on the element 32 overlap (that is, crosstalk occurs). FIG. 3B is a diagram for explaining this state. In FIG. 3B, light beams from the partial pupils 14 a to 14 p on the imaging optical system 11 are incident on the micro lenses 35 n 1 to 35 n 5 and incident on the sub imaging element 32. In the state shown in FIG. 3B, for example, the light beam r1 transmitted through the microlens 35n2 through the partial pupil 14b enters the light receiving element p included in the range in which the microlens 35n3 is vertically projected. For example, the light beam r2 that has passed through the microlens 35n3 through the partial pupil 14j also enters the light receiving element p. Therefore, since the light beam that has entered the sub-imaging element 32 through the partial pupils 14a to 14p of the imaging optical system 11 cannot be detected correctly, the aberration of the imaging optical system 11 cannot be measured.

  In view of this, in the imaging apparatus 1 of the present embodiment, the imaging optical system 11 is a lens brighter than the microlens 35 by using the mask member 33 that partially shields the subject light from the imaging optical system 11. Even when the F value of the image optical system 11 is smaller than the F value of the microlens 35), the aberration measurement of the imaging optical system 11 can be performed. Hereinafter, aberration measurement using the mask member 33 will be described.

(Configuration of mask member)
FIG. 4 is a schematic view of the mask member 33 viewed from the lens barrel 10 side (subject side). The mask member 33 includes a light shielding part 36a that shields incident light from the imaging optical system 11 and a transparent part 36b that transmits the incident light.

  The light shielding portion 36a has a shape in which a rectangular portion is connected to the lower side of a substantially octagonal portion. A connecting portion 37 to the mask member driving device 34 is provided in the rectangular portion. The mask member 33 is configured to be rotatable on the yz plane about the connection portion 37 by the mask member driving device 34. Further, the connecting portion 37 of the mask member 33 is configured to be movable up and down on the yz plane by the mask member driving device 34.

  The transparent portion 36b has a shape in which the inside of the substantially octagonal portion of the light shielding portion 36a is pulled out into a substantially circular shape. That is, the periphery of the transparent portion 36b is a light shielding portion 36a. In the imaging apparatus 1, the transparent portion 36b is made of an extremely thin transparent material, or is a transparent or air layer.

  The mask member 33 is configured to be driven to five positions, ie, a first position for aberration measurement, a second position, a third position, and a fourth position, and a retracted position for photographing. The mask member driving device 34 drives the mask member 33 on a surface (yz plane) perpendicular to the optical axis L of the imaging optical system 11 according to the control of the control device 23, and the mask member 33 is moved to the first. It is driven to any one of the position to the fifth position and the retracted position. The position indicated by the solid line in FIG. 4A is the first position, and the position indicated by the two-dot chain line in FIG. 4A is the second position. The position indicated by the solid line in FIG. 4B is the third position, and the position indicated by the two-dot chain line in FIG. 4B is the fourth position. The retracted position (not shown) is a position where the mask member 33 does not block the light beam from the imaging optical system 11 at all.

  As shown in FIG. 4A, the first position is a position where the center O of the transparent portion 36b of the mask member 33 is shifted from the optical axis L in the left direction (z direction) in the figure. The member 33 is a position where a diaphragm decentered leftward with respect to the optical axis L is formed. The second position is a position where the center O of the transparent portion 36b is shifted in the right direction (z direction) in the drawing from the optical axis L, and the mask member 33 is decentered in the right direction with respect to the optical axis L. This is the position where the aperture is formed. In addition, in the 1st position and the 2nd position, the transparent part 36b exists in the left-right symmetric position with respect to the optical axis L.

  When the mask member 33 is in the first position, the right portion of the subject light beam 14 that has passed through the imaging optical system 11 is drawn by the light-shielding portion 36a of the mask member 33, and leftward from the central region that includes the optical axis L of the subject light beam 14. Only a portion including the outer peripheral portion passes through the transparent portion 36 b of the mask member 33 and enters the focus detection unit 30. That is, the mask member 33 limits the cross section of the subject light beam 14 that has passed through the imaging optical system 11 to a shape that includes the optical axis L and is biased to the left with respect to the optical axis L.

  When the mask member 33 is in the second position, the left portion of the subject light beam 14 that has passed through the imaging optical system 11 is drawn by the light-shielding portion 36a of the mask member 33, and the right side from the central region including the optical axis L of the subject light beam 11L. Only a portion including the outer peripheral portion passes through the transparent portion 36 b of the mask member 33 and enters the focus detection unit 30. That is, the mask member 33 restricts the cross section of the subject light beam 14 that has passed through the imaging optical system 11 to a shape that includes the optical axis L and is biased to the right with respect to the optical axis L.

  As shown in FIG. 4B, the third position is a position where the center O of the transparent portion 36b of the mask member 33 is displaced in the upward direction (y direction) in the figure from the optical axis L, and the mask The member 33 is a position where a diaphragm decentered upward with respect to the optical axis L is formed. The fourth position is a position where the center O of the transparent portion 36b is displaced in the downward direction (y direction) in the drawing from the optical axis L, and the mask member 33 is decentered downward with respect to the optical axis L. This is the position where the aperture is formed. In the third position and the fourth position, the transparent portion 36b is in a vertically symmetrical position with respect to the optical axis L.

  When the mask member 33 is in the third position, the lower portion of the subject light beam 14 that has passed through the imaging optical system 11 is drawn by the light shielding portion 36a of the mask member 33, and from the central region including the optical axis L of the subject light beam 14 Only a portion including the upper outer peripheral portion passes through the transparent portion 36 b of the mask member 33 and enters the focus detection unit 30. That is, the mask member 33 limits the cross section of the subject light beam 14 that has passed through the imaging optical system 11 to a shape that includes the optical axis L and is biased upward with respect to the optical axis L.

  When the mask member 33 is in the fourth position, the upper portion of the subject light beam 14 that has passed through the imaging optical system 11 is drawn by the light-shielding portion 36a of the mask member 33, and is below the center region including the optical axis L of the subject light beam 14. Only a portion including the side outer peripheral portion passes through the transparent portion 36 b of the mask member 33 and enters the focus detection unit 30. That is, the mask member 33 limits the cross section of the subject light beam 14 that has passed through the imaging optical system 11 to a shape that includes the optical axis L and is biased downward with respect to the optical axis L.

  As shown in FIG. 4A, switching between the first position and the second position is performed by rotating the mask member 33 by a predetermined amount on the yz plane with the connecting portion 37 as the center. Further, as shown in FIG. 4B, switching between the third position and the fourth position is performed by moving the connecting portion 37 of the mask member 33 up and down a predetermined amount on the yz plane. The switching from the first position or the second position to the third position or the fourth position, or vice versa, is performed by rotating the mask member 33 by a predetermined amount on the yz plane with the connecting portion 37 as the center. The 33 connecting portions 37 may be moved up and down by a predetermined amount on the yz plane. Further, the switching from the first to fourth positions to the retracted position may be performed by rotating the mask member 33 by a predetermined amount on the yz plane with the connecting portion 37 as the center.

  FIG. 5 is a diagram in which the microlens 35 and the subject image formed on the sub-imaging device 32 as viewed from the Y direction are overlaid. FIG. 5 shows a state where the F value of the imaging optical system 11 is smaller than the F value of the microlens 35. In this type of focus detection unit 30, it is ideal that the light receiving element of the sub-imaging element 32 is projected onto the exit pupil of the imaging optical system 11, but actually the exit pupil of the imaging optical system 11, that is, Since the apparent position of the aperture image as viewed from the image side usually differs depending on the imaging optical system 11, the ideal state cannot always be obtained. Further, the F value corresponding to the width of one light receiving element of the sub image pickup element 32 is extremely large, and the image of the light receiving element on the exit pupil is not so blurred even if the image planes do not match. There is no problem even if it can not be in the state of. In FIG. 5, for convenience of illustration, the aperture image is drawn so as to be sharp, but for the reason described above, the image is actually slightly blurred. Further, the image of the mask member 33 is also somewhat blurred in the same manner as the light receiving element of the sub-imaging element 32, but in FIG. 5, it is drawn so as to be sharp for convenience of illustration.

  As shown in FIG. 5A, when the mask member 33 is in the retracted position, a subject image (aperture image) Im1 by a subject light beam that has passed through the imaging optical system 11 is sub-imaging element 32 by each microlens 35. Formed on top. Since the subject image Im1 is formed in each microlens 35 in a circular shape wider than the range in which the microlens 35 is vertically projected, as shown in FIG. It will overlap. The output from the light receiving element in this overlapping portion cannot be used for aberration measurement. In FIG. 5B, there is no overlap between the subject images Im1 in the vicinity of the center of the subject image Im1 (that is, the optical axis L), so the output from the light receiving element in this part can be used. Only the aberration corresponding to the central region of the pupil of the imaging optical system 11 can be measured, and the aberration corresponding to the region near the outer peripheral portion of the pupil of the imaging optical system 11 cannot be measured.

  On the other hand, when the mask member 33 is in the first position, the subject image (image of the mask member 33) Im2 by the subject light flux that has passed through the imaging optical system 11 and has passed through the transparent portion 36b of the mask member 33 is represented by each micro The lens 35 is formed on the sub imaging device 32. In each microlens 35, the correspondence between the subject light flux that has passed through the imaging optical system 11 and passed through the transparent portion 36 b of the mask member 33 and the light flux incident on the sub-imaging device 32 is as follows. The optical axis L is an axis of symmetry and the image is inverted vertically and horizontally. Accordingly, the subject image Im2 has a shape obtained by inverting the shape of the subject light beam 14 (FIG. 4A) restricted by the mask member 33 at the first position vertically and horizontally, as shown in FIG. As shown in the figure, the mask member 33 has a shape only including a part from the center region of the subject image Im1 to the right outer periphery when the mask member 33 is in the retracted position.

  Therefore, as shown in FIG. 5C, when the mask member 33 is at the first position, the subject image Im2 has a portion where the adjacent microlenses 35 overlap with each other when the mask member 33 is at the retracted position. It is narrower than that. A portion where the subject image Im2 does not overlap between adjacent microlenses 35 can be used for aberration measurement. For example, in the range where the subject image Im2 is formed, a light reception signal by the light receiving element from the light receiving element pO on the optical axis L to the light receiving element pR near the right outer peripheral part can be used for aberration measurement. The light receiving element pO on the optical axis L receives the light beam that has passed through the central region of the pupil of the imaging optical system 11, and the light receiving element pR near the right outer peripheral part is the left outer peripheral part of the pupil of the imaging optical system 11. The light beam that has passed through the region close to is received. Therefore, the aberration corresponding to the left partial pupil from the optical axis L of the imaging optical system 11 can be calculated.

  On the other hand, when the mask member 33 is at the second position, as shown in FIG. 5D, the image Im2 by the subject light flux has a shape obtained by inverting the subject image Im2 when the mask member 33 is at the first position. Thus, the mask member 33 has a shape that includes only a part including the center region of the subject image Im1 to the left outer peripheral portion when the mask member 33 is in the retracted position. Therefore, for example, in the range where the subject image Im2 is formed, a light reception signal by the light receiving element from the light receiving element pO on the optical axis L to the light receiving element pL near the left outer peripheral part can be used for aberration measurement. Thereby, the aberration corresponding to the right partial pupil from the optical axis L of the imaging optical system 11 can be calculated.

  Therefore, the aberration in the lateral direction (z direction) of the imaging optical system 11 can be measured by driving the mask member 33 to the first position and the second position and performing aberration calculations respectively.

  The subject image Im2 when the mask member 33 is at the third position or the fourth position has a shape obtained by rotating the subject image Im2 when the mask member 33 is at the first position or the fourth position by 90 degrees. The illustration is omitted.

  When the mask member 33 is in the third position, the subject image Im2 has a shape that includes only a portion including the center region of the subject image Im1 and the lower outer peripheral portion when the mask member 33 is in the retracted position. Therefore, for example, in the range where the subject image Im2 is formed, a light reception signal by the light receiving element from the light receiving element on the optical axis L to the light receiving element near the lower outer peripheral portion can be used for aberration measurement. Thereby, the aberration corresponding to the upper partial pupil from the optical axis L of the imaging optical system 11 can be calculated.

  Further, the subject image Im2 when the mask member 33 is at the fourth position has a shape of only a part including the central region to the upper outer peripheral portion of the subject image Im1 when the mask member 33 is at the retracted position. Therefore, for example, in the range where the subject image Im2 is formed, a light reception signal by the light receiving element from the light receiving element on the optical axis L to the light receiving element near the upper outer peripheral portion can be used for aberration measurement. Thereby, the aberration corresponding to the partial pupil below the optical axis L of the imaging optical system 11 can be calculated.

  Therefore, by driving the mask member 33 to the third position and the fourth position and performing aberration calculations, the aberration in the longitudinal direction (y direction) of the imaging optical system 11 can be measured.

  As described above, even when the imaging optical system 11 is a brighter lens than the microlens 35 (the F value of the imaging optical system 11 is smaller than the F value of the microlens 35), the mask member 33 is removed. Aberration measurement can be performed by driving to the first to fourth positions.

(Description of aberration measurement processing)
Next, the flow of aberration measurement processing executed in the present embodiment will be described. When the user sets the operation mode of the camera body 20 to the aberration measurement mode using an operation member such as a mode dial, for example, the control device 23 starts the aberration measurement process.

  First, the control device 23 controls the mask member driving device 34 to drive the mask member 33 to the first position. Further, the control device 23 sets the photographing F value of the lens barrel 10 to the open F value. Here, it is assumed that the open F value of the lens barrel 10 is smaller than the F value of the microlens 35. Then, the control device 23 performs a display prompting the rear monitor 41 to prepare a predetermined vertical stripe pattern chart.

  As described above, when the lens barrel 10 is of a type in which the photographing F value cannot be set from the camera body 20 (for example, a lens barrel having a mechanism in which the photographing F value can be set only by a manually operated aperture ring). Instead of setting the photographing F value to the open F value, the control device 23 displays a message prompting the rear monitor 41 to set the open F value.

  Here, the user prepares a predetermined vertical stripe pattern chart, puts it in the angle of view, manually observes a so-called through image displayed on the viewfinder, focuses the chart manually, and performs a predetermined operation such as a release operation. . When detecting that this predetermined operation has been performed, the control device 23 causes the sub image sensor 32 to perform imaging, and temporarily stores the output from each light receiving element in a memory (not shown). Based on the output of the sub-imaging device 32, the control device 23 calculates the aberration corresponding to the left partial pupil from the optical axis L of the imaging optical system 11, as described above, and stores the calculation result in a memory (not shown). Memorize temporarily.

  Further, the control device 23 drives the mask member 33 to the second position, causes the sub imaging element 32 to perform imaging, and temporarily stores the output from each light receiving element in a memory (not shown). Based on the output of the sub-imaging device 32, the control device 23 calculates the aberration corresponding to the right partial pupil from the optical axis L of the imaging optical system 11 as described above, and the calculation result is not shown. Temporarily store in the memory.

  Next, the control device 23 drives the mask member 33 to the third position. Then, the control device 23 performs a display prompting to prepare a predetermined horizontal stripe pattern chart. Here, the user prepares a predetermined horizontal stripe pattern chart, puts it in the angle of view, manually focuses, and performs a predetermined operation such as a release operation. When detecting that this predetermined operation has been performed, the control device 23 causes the sub image sensor 32 to perform imaging, and temporarily stores the output from each light receiving element in a memory (not shown). Based on the output of the sub-imaging device 32, the control device 23 calculates the aberration corresponding to the upper partial pupil from the optical axis L of the imaging optical system 11 as described above, and the calculation result is not shown. Temporarily store in the memory.

  In addition, the control device 23 drives the mask member 33 to the fourth position, causes the sub imaging element 32 to perform imaging, and temporarily stores the output from each light receiving element in a memory (not shown). Then, based on the output of the sub-imaging device 32, the control device 23 calculates the aberration corresponding to the partial pupil below the optical axis L of the imaging optical system 11, as described above, and the calculation result is invalid. Temporarily store in the illustrated memory.

  In this way, when the control device 23 measures the aberration of the imaging optical system 11 with respect to the vertical and horizontal patterns, for example, together with information specifying the lens barrel 10 such as the name of the lens barrel 10 and the model name, the measurement result Is stored in a memory (not shown). When the lens barrel 10 is a so-called zoom lens, the aberration needs to be measured for each zoom position where focus detection or photographing is performed. Therefore, the control device 23 stores information on the state of the lens barrel 10 that affects the zoom position at the time of measurement and other aberrations, together with the measurement result of the aberration and the above-described “information for specifying the lens barrel 10”. deep. The “information for specifying the lens barrel 10”, the zoom position, and the like may be input by the user, or by some means (for example, data communication via an electrical contact provided on the lens mount 9) from the lens barrel 10. You may get it.

  In the above example, the user manually performs the focusing on the chart. Instead, the focusing is performed by the automatic focusing using the focus detection unit 30 as in the normal shooting. May be. Alternatively, the focus detection unit 30 may be used to display focus adjustment information to assist manual focusing. In either case, there is no problem because the aberration state does not change greatly even if the focus is slightly deviated.

  Further, in the above example, assuming that the F value of the imaging optical system 11 is smaller than the F value of the microlens 35, the mask member 33 is driven to the first to fourth positions, and the aberration is measured. I tried to do it. However, when the F value of the imaging optical system 11 is greater than or equal to the F value of the microlens 35, no crosstalk occurs between the adjacent microlenses 35. Therefore, in such a case, instead of driving the mask member 33 to the first to fourth positions to measure the aberration, the mask member 33 is driven to the retracted position and the received light signal is read out only once. Aberration measurement may be performed.

(Explanation of focus detection operation)
Next, the focus detection operation in this embodiment will be described. When shooting a still image, the user sets the operation mode of the camera body 20 to the still image shooting mode using an operation member such as a mode dial, for example. In response to this, when the mask member 33 is located at a position other than the retracted position, the control device 23 drives the mask member 33 to the retracted position. When the user performs a predetermined photographing preparation operation such as pressing the release switch halfway, the control device 23 uses the focus detection unit 30 to detect the focus of the imaging optical system 11. Hereinafter, details of focus detection performed in accordance with the shooting preparation operation will be described.

  When a lens barrel 10 of a type that cannot transmit aberration information is attached, the control device 23 performs the above-described “lens barrel” before performing focus detection (for example, when a still image shooting mode is set). The memory is searched for “information specifying 10” to determine whether aberration information is stored. The “information for specifying the lens barrel 10” is, for example, a user inputting a name or the like for specifying the lens barrel 10 or data communication with the lens barrel 10 for the model name of the lens barrel 10 or the like. It is acquired by a method such as receiving. If the aberration information is stored in the memory, the control device 23 corrects the focus detection result using the aberration information in the focus detection. Thus, even when a lens barrel 10 of a type that cannot transmit aberration information is used, if the aberration information is created in advance in the aberration measurement mode, the lens barrel 10 that can transmit aberration information is used. As in the case of performing, it is possible to perform focus detection with high accuracy using aberration information.

  The control device 23 performs focus detection by a so-called phase difference detection method using the output of the sub imaging element 32. That is, the focus adjustment state of the imaging optical system 11 is determined as the defocus amount based on the positional deviation amount of the pair of subject images formed by the pair of light beams that have passed through the pair of regions on the pupil plane of the imaging optical system 11. Detect in the form of

  The control device 23 selects any one of a plurality of focus areas provided on the photographing screen, and a waveform obtained by connecting the output of the third light receiving element to the left from the center of each microlens 35 included in the focus area. The defocus amount is detected based on the amount of positional deviation between the composite image represented and the composite image represented by the waveform connecting the outputs of the third light receiving elements to the right from the center. For example, for the microlenses 35n1 to 35n5 arranged continuously, the control device 23 connects the outputs q (n1) to q (n5) of the third light receiving elements to the left from the center of each microlens {q (I)} and a positional deviation amount between the image corresponding to the signal sequence {r (i)} in which the outputs r (n1) to r (n5) of the third light receiving element are connected to the right from the center. Is detected. The signal sequences {q (i)} and {r (i)} represent signal outputs of the same image on the second planned focal plane 5b, and by comparing these two signal sequences, the imaging optical system 11, the amount of positional deviation between the pair of subject images formed on the second planned focal plane 5b can be detected. Note that the pair of signal sequences {q (i)} and {r (i)} may be created from the outputs of the light receiving elements at positions different from those described above.

  Next, the procedure of focus detection by the control device 23 will be described in detail. First, the output of the sub-imaging device 32 is converted into a digital signal by an A / D converter (not shown) and temporarily stored in a memory (not shown). The control device 23 reads the output data of the sub-imaging device 32 from the memory, and the first signal sequence {q (i)} = q (1), q (2), q (3),. Create a sequence {r (i)} = r (1), r (2), r (3),. The control device 23 selects a plurality of microlenses 35 from a range to be targeted for focus detection among all the light receiving elements of the sub-imaging element 32, and the first signal sequence {q (i)} and the second signal are selected. Create a sequence {r (i)}. The range desired to be the focus detection target may be determined, for example, by allowing the user to specify a so-called focus area, or may be a predetermined range.

Based on the first signal sequence {q (i)} and the second signal sequence {r (i)} thus obtained, the control device 23 performs an image shift calculation by a well-known method and calculates a defocus amount. . A method for calculating a defocus amount from a pair of signal sequences {q (i)} and {r (i)} is well known. First, a first signal sequence {q (i)} and a second signal sequence {r (I)} The correlation amount C (N) of the corresponding pair of images is obtained from (i = 1, 2, 3,...).
C (N) = Σ | q (i) −r (j) | (5)
In the above equation (5), j−i = N, and N is the number of shifts. Further, Σ represents a total calculation of a predetermined range related to i.

Next, the control device 23 obtains the shift amount as follows from the correlation amount C (N) obtained discretely by the above equation (5). Here, among the correlation amounts C (N), the correlation amount giving a minimum value when the shift amount N = N0 is C0, the correlation amount in the shift amount (N0-1) is Cr, and the correlation in the shift amount (N0 + 1). Let the amount be Cf. The control device 23 obtains a precise shift amount Na from the arrangement of the correlation amounts Cr, C0, Cf.
DL = (Cr−Cf) / 2 (6)
E = max {(Cf−C0), (Cr−C0)} (7)
Na = N0 + DL / E (8)

The control device 23 adds a correction amount (constant CONST) according to the position of the focus detection surface to the shift amount Na obtained here, and calculates an image shift amount Δn = Na + CONST on the focus detection surface. Further, the defocus amount Df before aberration correction is calculated by multiplying the image shift amount Δn by a constant Kf depending on the detection opening angle.
Df = Kf · Δn (9)

  Then, the control device 23 corrects the defocus amount Df based on the aberration information, and calculates a more accurate defocus amount in which the influence of the aberration is corrected. Specifically, first, a pair of pupils used for focus detection (for example, a pupil corresponding to the signal sequence {q (i)} and a pupil corresponding to the signal sequence {r (i)}) are used. An F value representing the opening of each center of gravity position is obtained, and the best image plane position corresponding to the F value is determined from the aberration information. Then, the best image plane position corresponding to the photographing F value is similarly determined from the aberration information. Finally, the defocus amount Df is corrected by an amount corresponding to the difference between the two best image plane positions. When data corresponding to the above calculation is not included in the aberration information, interpolation may be appropriately performed from information on other adjacent F values.

  The control device 23 drives the focus lens of the imaging optical system 11 by an amount corresponding to the calculated defocus amount, performs focus adjustment, or causes the finder or rear monitor 41 to display the current focus state such as a front pin or a rear pin. To support manual focus adjustment by the user.

  If the F value of the imaging optical system 11 is smaller than the F value of the microlens 35 at the time of focus detection (the imaging optical system 11 is brighter than the microlens 35), crossing between adjacent microlenses 35 Talk occurs and normal focus detection cannot be performed. Therefore, the control device 23 of the present embodiment controls the diaphragm 12 of the lens barrel 10 to be equal to or higher than the F value of the microlens 35 at the time of focus detection, so that such crosstalk does not occur. In addition, when the lens barrel 10 that cannot control the photographing F value from the camera body 20 is attached, the control device 23 manually sets the F value by displaying a message on the rear monitor 41, for example. The user is prompted to set the F value of the microlens 35 or higher.

  Thereafter, when a predetermined photographing operation is performed by the user, for example, the release switch is fully pressed, the control device 23 adjusts the aperture 12 of the lens barrel 10 according to the set F value at the time of photographing. The subject image is picked up by the above, image data is created and stored in a storage medium (not shown) (for example, a memory card). Alternatively, when the lens barrel 10 that cannot control the photographing F value from the camera body 20 is attached, the image is taken as it is. In this case, it is assumed that the photographer manually sets a desired aperture prior to the photographing operation.

According to the imaging apparatus 1 according to the first embodiment described above, the following operational effects are obtained.
(1) The imaging apparatus 1 includes a plurality of microlenses 35 that are two-dimensionally arranged so that a light beam that has passed through the imaging optical system 11 is incident thereon, and the microlens 35 corresponding to each of the plurality of microlenses 35. The light-receiving element array 32 having a plurality of light-receiving elements arranged on the rear side and a part of the light beam that has passed through the imaging optical system 11 are shielded, whereby the cross-section of the light beam that has passed through the imaging optical system 11 is A shielding state (first to fourth positions) that restricts the imaging optical system 11 to a shape that is deviated with respect to the optical axis L, and a passing state that allows the light beam that has passed through the imaging optical system 11 to pass through without being blocked ( Of the light receiving element array 32 corresponding to the light beam that is transmitted through the imaging optical system 11 having an open F value and partially blocked by the mask member 33 in the shielding state. Imaging optics based on output signal And a control unit 23 for detecting the aberration information about the 11 aberrations, the. Thereby, even when the F value of the imaging optical system 11 is smaller than the F value of the microlens 35 (that is, when the imaging optical system 11 is a brighter lens than the microlens 35), the aberration is measured. Can do. In addition, since the imaging apparatus 1 itself can measure aberrations, it is not necessary to use a dedicated machine for measuring aberrations, and the operation is simple.

(2) In the imaging device 1 of the above (1), based on the output signal of the light receiving element array 32 corresponding to the light beam transmitted through the imaging optical system 11 having a predetermined F value for focus detection, the imaging optical system 11 A control device 23 that detects the focus adjustment state, and a control device 23 that corrects the detected focus adjustment state of the imaging optical system 11 based on the aberration information and the photographing F value. As a result, focus detection can be performed accurately even with a lens that cannot communicate aberration information. In addition, since the aberration detection and the focus detection are shared by the microlens 35 and the light receiving element array 32, it is not necessary to provide dedicated parts for each, and the cost can be reduced.

(3) In the imaging device 1 of the above (1) or (2), the mask member 33 has a first shielding state (first position or third position) and a second shielding state (second position) as a shielding state. Or the fourth position), and in the first shielding state and the second shielding state, the cross section of the light beam transmitted through the imaging optical system 11 includes the optical axis L of the imaging optical system 11, In addition, the shape is limited to different shapes that are different from each other with respect to the optical axis. Further, in the first shielding state (first position or third position), the mask member 33 displays the cross section of the light beam transmitted through the imaging optical system 11 as the first portion (left side portion or upper portion) of the outer periphery of the cross section. ) To the shape including the optical axis L, and in the second shielding state (the second position or the fourth position), the cross section of the light beam transmitted through the imaging optical system 11 is set to the second portion on the outer periphery of the cross section. The first part (left part or upper part) and the second part (right part or lower part) are limited with respect to the optical axis L. And symmetrical positions. Thereby, the aberration in the predetermined direction (horizontal direction or vertical direction) of the imaging optical system 11 can be measured.

(Second Embodiment)
FIG. 6 is a diagram illustrating a configuration of the imaging apparatus 2 according to the second embodiment of the present invention. In the following description, the same parts as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof is omitted. The imaging device 2 includes a lens barrel 10, a camera body 120, and an intermediate adapter 130 that is mounted between the lens barrel 10 and the camera body 120. The camera body 120 differs from the camera body 20 of the first embodiment in that it does not have the pellicle mirror 21 and the focus detection unit 30, but the other configurations are the same. That is, the camera body 120 is a camera body having a relatively short metal back and no member that reflects the subject light.

  The intermediate adapter 130 is an adapter for mounting the lens barrel 10 having a longer metal back than the camera body 120 to the camera body 120. The intermediate adapter 130 is attached to the camera body 120 via the body side mount 131 and attached to the lens barrel 10 via the lens side mount 132. On the optical axis L of the imaging optical system 11 in the intermediate adapter 130, a pellicle mirror 21 that branches the subject light that has passed through the imaging optical system 11 in two directions is provided. A focus detection unit 30 is further provided in the intermediate adapter 130. The pellicle mirror 21 directs one of the branched subject lights toward the main image sensor 22 of the camera body 120 and the other toward the focus detection unit 30. The configuration of the focus detection unit 30 is the same as that of the first embodiment.

  Further, on the optical axis L of the imaging optical system 11 in the intermediate adapter 130, a part of subject light that has passed through the imaging optical system 11 is shielded from the pellicle mirror 21 to the imaging optical system 11 side. A mask member 33 is provided. A mask member driving device 34 for driving the mask member 33 is further provided in the intermediate adapter 130. The configurations of the mask member 33 and the mask member driving device 34 are the same as those in the first embodiment.

  The intermediate adapter 130 further includes an adapter control device 133 that controls each unit in the intermediate adapter 130. The adapter control device 133 is electrically connected to the control device 23 in the camera body 120 via the body side mount 131 and performs various communications. When notified from the camera body 120 that the aberration measurement mode has been set, the adapter control device 133 executes the aberration measurement process in the same manner as in the first embodiment. In addition, when notified from the camera body 120 that a predetermined photographing preparation operation has been performed, the adapter control device 133 executes focus detection processing based on aberration information in the same manner as in the first embodiment.

According to the intermediate adapter 130 according to the second embodiment described above, the following operational effects can be obtained.
The intermediate adapter 130 includes a plurality of microlenses 35 that are two-dimensionally arranged so that a light beam that has passed through the imaging optical system 11 enters, and a rear side of the microlens 35 corresponding to each of the plurality of microlenses 35. The light-receiving element array 32 having a plurality of light-receiving elements arranged in the light-receiving element array 32 and a part of the light beam that has passed through the imaging optical system 11 are shielded so that the cross section of the light beam that has passed through the imaging optical system 11 A shielding state (first to fourth positions) limited to a shape deviated with respect to the optical axis L of the system 11 and a passing state (retraction position) in which the light beam transmitted through the imaging optical system 11 passes without being shielded. To the output signal of the light receiving element array 32 corresponding to the light beam that is transmitted through the imaging optical system 11 having an open F value and partially blocked by the mask member 33 in the shielding state. Based on the imaging light Comprising an adapter control unit 133 for detecting the aberration information on the aberration of the system 11. Further, the intermediate adapter 130 detects the focus adjustment state of the imaging optical system 11 based on the output signal of the light receiving element array 32 corresponding to the light beam transmitted through the imaging optical system 11 having a predetermined F value for focus detection. An adapter controller 133 and an adapter controller 133 that corrects the detected focus adjustment state of the imaging optical system 11 based on the aberration information and the imaging F value. As described above, according to the intermediate adapter 130 according to the second embodiment, aberration measurement and focus detection can be performed in the same manner as in the first embodiment. Therefore, the same operational effects as those in the first embodiment can be performed. Is obtained.

(Modification 1)
In the embodiment described above, the mask member 33 may be driven to the fifth position for focus detection. As shown in FIG. 7, the fifth position is a position where the center O of the transparent portion 36 b of the mask member 33 coincides with the optical axis L of the imaging optical system 11. That is, the transparent portion 36b of the mask member 33 is symmetrical with respect to the optical axis L. By driving the mask member 33 to the fifth position, the subject luminous flux 14 that has passed through the imaging optical system 11 can be narrowed down.

  When the F value of the imaging optical system 11 is smaller than the F value of the microlens 35 at the time of focus detection (the imaging optical system 11 is brighter than the microlens 35), crosstalk occurs between adjacent microlenses 35. Therefore, normal focus detection cannot be performed. Therefore, the control device 23 of Modification 1 controls the mask member driving device 34 to drive the mask member 33 to the fifth position during focus detection. The size of the transparent portion 36b of the mask member 33 is assumed to be smaller than the diameter of the subject light beam from the imaging optical system 11 having the same F value as the microlens 35, for example. As a result, the subject light flux that has passed through the imaging optical system 11 is narrowed by the mask member 33 at the fifth position, so that it is possible to prevent crosstalk from occurring between the adjacent microlenses 35.

  Note that the size of the transparent portion 36b of the mask member 33 is not necessarily smaller than the diameter of the subject light beam from the imaging optical system 11 having the same F value as that of the micro lens 35. It is sufficient that the cross-talk does not occur at least in the light receiving element that performs focus detection.

  FIG. 7 shows an example in which the mask member 33 limits the cross section of the subject light beam transmitted through the imaging optical system 11 to a symmetrical shape in the vertical and horizontal directions with respect to the optical axis L. The shape may not be symmetrical. It suffices if focus detection is possible, and at least a shape with less deviation with respect to the optical axis L than the case where the mask member 33 is in the first to fourth positions is sufficient.

  As described above, in the first modification, the mask member 33 can be further switched to the focus detection shielding state (fifth position), and the fifth position is a cross-section of the light beam transmitted through the imaging optical system 11. Is limited to a shape that includes the optical axis L of the imaging optical system 11 and is less biased than the first to fourth positions with respect to the optical axis L. 11, the focus adjustment state of the imaging optical system 11 is detected based on the output signal of the light receiving element array 32 corresponding to the light beam that has passed through 11 and is partially shielded by the mask member 33 at the fifth position. As a result, the subject luminous flux that has passed through the imaging optical system 11 is automatically reduced, and crosstalk between adjacent microlenses 35 can be prevented. Therefore, for example, even when the lens barrel 10 that cannot control the photographing F value from the camera body 20 is mounted, normal focus detection is automatically performed without causing the user to manually adjust the F value. It can be carried out.

(Modification 2)
The arrangement of the microlenses 35 is not limited to that shown in FIG. For example, as shown in FIG. 8, a microlens array 31 having a honeycomb arrangement in which microlenses 35 are formed in a substantially hexagonal shape may be used. FIG. 8 is a schematic diagram of a subject image formed on the sub-imaging device 32 in the modified example 2 in a state where the F value of the imaging optical system 11 is smaller than the F value of the microlens 35, as in FIG. 5. FIG. Similar to the above-described embodiment, the subject image Im1 when the mask member 33 is in the retracted position is formed in a circular shape wider than the range in which the microlens 35 is vertically projected, as shown in FIG. Therefore, the adjacent microlenses 35 partially overlap each other.

  On the other hand, the subject image Im2 when the mask member 33 is at the first position has a shape of only a part including the center region to the right outer peripheral portion of the subject image Im1 when the mask member 33 is at the retracted position. Therefore, as shown in FIG. 8B, for example, in the range where the subject image Im2 is formed, the light receiving signal by the light receiving element from the light receiving element pO on the optical axis L to the light receiving element pR near the right outer peripheral portion. Can be used for aberration measurement. Thereby, the aberration corresponding to the left partial pupil from the optical axis L of the imaging optical system 11 can be calculated.

  Further, as shown in FIG. 8C, the subject image Im2 when the mask member 33 is at the second position has a shape obtained by inverting the subject image Im2 when the mask member 33 is at the first position. In addition, the mask member 33 has a shape including only a part including the center area of the subject image Im1 to the left outer peripheral portion when the mask member 33 is in the retracted position. Therefore, for example, in the range where the subject image Im2 is formed, a light reception signal by the light receiving element from the light receiving element pO on the optical axis L to the light receiving element pL near the left outer peripheral part can be used for aberration measurement. Thereby, the aberration corresponding to the right partial pupil from the optical axis L of the imaging optical system 11 can be calculated.

  Therefore, similarly to the above-described embodiment, the mask member 33 is driven to the first position and the second position, and the aberration calculation is performed, so that the horizontal direction (z direction) of the imaging optical system 11 is calculated. Aberration can be measured.

  In the second modification, the aberration of the imaging optical system 11 may be measured in the direction of ± 60 degrees with respect to the lateral direction (z direction). In this case, the aberration may be measured by driving the mask member 33 so that the transparent portion 36b of the mask member 33 is decentered in the direction of ± 60 degrees with respect to the lateral direction (z direction).

(Modification 3)
In the above-described embodiment, the example in which the shape of the transparent portion 36b of the mask member 33 is circular has been described. However, the shape is not limited thereto, and may be, for example, a polygonal shape. The shape of the transparent portion 36b of the mask member 33 is the image of the light receiving element on the optical axis L when the back projection image of the light receiving element of the sub imaging element 32 by the microlens array 31 is taken into account when inserted into the photographing optical path. And any shape of the light-receiving element close to the outermost peripheral part in one direction of the aperture opening, and any shape that blocks light poured from the adjacent microlens 35 to the light-receiving element close to the outermost peripheral part may be used.

  In the above-described embodiment, the example in which the shape of the transparent portion 36b of the mask member 33 is fixed has been described. For example, the mask member 33 is composed of a plurality of members, and the shape and size of the transparent portion 36b are the same. It may be configured to be variable.

(Modification 4)
Instead of the camera body 20 described above, the above-described mask member 33 and mask member driving device 34 may be provided in a camera body having a configuration close to a general single-lens reflex camera. In this case, the mask member 33 may be provided in front of the quick return mirror, or may be provided in front of the reflection surface of the sub mirror.

  In the case of the fourth modification, subject light is incident on the focus detection unit through the sub mirror while the quick return mirror is in the down position. The sub mirror has, for example, a horizontally long shape that covers almost the entire width of the imaging range, and the focus detection unit also covers the entire horizontal range of the imaging range. In this case, there are restrictions such that the aberration at a high image height in the vertical direction of the imaging range cannot be measured, and the aberration measurement by the light passing through the peripheral portion in the vertical direction of the imaging optical system 11 cannot be performed. However, under the assumption that the imaging optical system 11 is rotationally symmetric about the optical axis L, an aberration correction value can be determined from the measurable aberration. By using the aberration correction value determined in this way, more accurate focus detection can be performed than when no aberration correction is performed.

(Modification 5)
In the above-described embodiment, the example in which the aberration measurement is performed by driving the mask member 33 to the first to fourth positions to decenter the transparent portion 36b (that is, the diaphragm) vertically and horizontally has been described. However, the aberration may be measured more precisely by decentering the transparent portion 36b in more directions. Conversely, aberration measurement may be performed by driving the mask member 33 only to the first position and the second position (that is, by decentering the transparent portion 36b only in the left-right direction). The aberration information in the necessary direction of the necessary part that cannot be directly measured may be determined based on the assumption that the aberration is rotationally symmetric.

(Modification 6)
Instead of the pellicle mirror 21, a pellicle film on which a hologram element is formed may be provided. Since the reflection angle of the light beam having a specific wavelength can be changed by the hologram element, the same configuration as the pellicle mirror 21 can be realized at a shallower angle than the pellicle mirror 21. In this case, although subject light lacking only a light beam having a specific wavelength is used for imaging, there is almost no effect on normal imaging because only light in a very narrow wavelength range is missing. Accordingly, since the flange back can be shortened, for example, when the lens barrel 10 is mounted via an intermediate adapter or the like, it is possible to cope with various types of lens barrels 10.

(Modification 7)
Similarly to the case of aberration measurement, focus detection with driving of the mask member 33 may be performed. That is, the defocus amount may be calculated from the light reception signal obtained by driving the mask member 33 to the first position and the light reception signal obtained by driving the mask member 33 to the second position. However, as described above, the defocus amount cannot be detected correctly when the subject images that are the basis of the two light reception signals are different, for example, when a moving subject is photographed, so that the mask member 33 is driven only when designated by the user. It is desirable to perform focus detection involving For example, when the user shoots a fixed subject, the above-described focus detection mode is selected, and in other cases, the focus detection mode described in the first embodiment is selected. Configure the device.

(Modification 8)
Instead of driving the mask member 33 by the mask member driving device 34, the light shielding portion 36a and the transparent portion 36b may be configured by liquid crystal to switch between shielding and transmitting the light beam from the microlens 35.

(Modification 9)
The aberration information may be information other than the image shift amounts Sa to Sp described above. For example, it may be intermediate data that appears during the calculation for correcting the defocus amount. In addition, any data format may be used as long as the data can finally reduce the influence of aberration from the focus detection result.

(Modification 10)
The present invention can be applied even when the F value at the time of aberration measurement is not set to the open F value as in each of the above-described embodiments. However, in this case, it is not possible to measure the aberration at a location shielded by the diaphragm 12 (a partial pupil farther from the optical axis L).

  As long as the characteristics of the present invention are not impaired, the present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention. .

DESCRIPTION OF SYMBOLS 1, 2 ... Imaging device, 10 ... Lens barrel, 11 ... Imaging optical system, 12 ... Aperture, 20, 120 ... Camera body, 21 ... Pellicle mirror, 22 ... Main imaging device, 23 ... Control device, 30 ... Focus Detection unit, 31 ... micro lens array, 32 ... sub-imaging device, 33 ... mask member, 34 ... mask member driving device, 35 ... micro lens, 36a ... light-shielding part, 36b ... transparent part, 40 ... electronic viewfinder unit, 41 ... rear monitor, 42 ... eyepiece, 130 ... intermediate adapter, 133 ... adapter controller

Claims (10)

A plurality of microlenses arranged two-dimensionally so that a light beam transmitted through the imaging optical system is incident;
A light receiving element array having a plurality of light receiving elements arranged on the rear side of the micro lens corresponding to each of the plurality of micro lenses;
Shielding by limiting a part of the light beam transmitted through the imaging optical system to a shape biased with respect to the optical axis of the imaging optical system by shielding a part of the light beam transmitted through the imaging optical system. Shielding means capable of switching between a state and a passing state in which the light beam transmitted through the imaging optical system passes without being shielded;
The imaging optical system based on an output signal of the light receiving element array corresponding to a light beam that passes through the imaging optical system having a first F value and is partially shielded by the shielding means in the shielding state Aberration detecting means for detecting aberration information relating to the aberration of
An imaging apparatus comprising: The imaging device according to claim 1,
Focus detection means for detecting a focus adjustment state of the imaging optical system based on an output signal of the light receiving element array corresponding to a light beam transmitted through the imaging optical system having a second F value;
Correction means for correcting the focus adjustment state of the imaging optical system detected by the focus detection means based on the aberration information and the F value at the time of imaging;
An image pickup apparatus further comprising: The imaging device according to claim 1 or 2,
The shielding means can be switched between the first shielding state and the second shielding state as the shielding state, and is transmitted through the imaging optical system in the first shielding state and the second shielding state. An imaging apparatus characterized in that the cross section of the light beam is limited to different shapes including the optical axis of the imaging optical system and different from each other with respect to the optical axis. The imaging device according to claim 3.
In the first shielding state, the shielding means limits the cross section of the light beam transmitted through the imaging optical system to a shape including the first portion of the outer periphery of the cross section to the optical axis, and the second In the shielding state, the cross section of the light beam transmitted through the imaging optical system is limited to a shape including from the second part of the outer periphery of the cross section to the optical axis, and the first part and the second part are An imaging apparatus characterized by being symmetrical with respect to an optical axis. The imaging device according to claim 2,
The shielding means can be further switched to the third shielding state as the shielding state, and in the third shielding state, the cross section of the light beam transmitted through the imaging optical system is changed to the light of the imaging optical system. Limiting to a shape that includes an axis and less biased relative to the optical axis than the first and second shielding states;
The focus detection unit transmits the light receiving light corresponding to a light beam that is transmitted through the imaging optical system having an F value equal to or less than the second F value and partially blocked by the shielding unit in the third shielding state. An imaging apparatus that detects a focus adjustment state of the imaging optical system based on an output signal of an element array. In the imaging device according to any one of claims 1 to 5,
The imaging apparatus, wherein the first F value is smaller than the F value of the microlens. In the imaging device according to any one of claims 1 to 6,
The imaging apparatus, wherein the first F value is an open F value of the imaging optical system. In the imaging device according to any one of claims 1 to 7,
An imaging apparatus, further comprising attachment means to which an interchangeable lens having the imaging optical system can be attached and detached. A plurality of microlenses arranged two-dimensionally so that a light beam transmitted through the imaging optical system is incident;
A light receiving element array having a plurality of light receiving elements arranged on the rear side of the micro lens corresponding to each of the plurality of micro lenses;
Shielding by limiting a part of the light beam transmitted through the imaging optical system to a shape biased with respect to the optical axis of the imaging optical system by shielding a part of the light beam transmitted through the imaging optical system. Shielding means capable of switching between a state and a passing state in which the light beam transmitted through the imaging optical system passes without being shielded;
The imaging optical system based on an output signal of the light receiving element array corresponding to a light beam that passes through the imaging optical system having a first F value and is partially shielded by the shielding means in the shielding state Aberration detecting means for detecting aberration information relating to the aberration of
An intermediate adapter comprising: The intermediate adapter according to claim 9,
The intermediate adapter, wherein the first F value is smaller than the F value of the microlens.

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