WO2022163208A1

WO2022163208A1 - Phase difference detection device, lens device, and imaging apparatus

Info

Publication number: WO2022163208A1
Application number: PCT/JP2021/046884
Authority: WO
Inventors: 泰孝島田; 洋一岩崎
Original assignee: 富士フイルム株式会社
Priority date: 2021-01-29
Filing date: 2021-12-17
Publication date: 2022-08-04
Also published as: JPWO2022163208A1

Abstract

The present invention provides a phase difference detection device, a lens device, and an imaging apparatus with which it is possible to suppress a decrease in distance measurement accuracy in a largely out-of-focus state.　An imaging apparatus (100) comprises: a beam splitter (16) (branching part) that branches the optical path of subject light which has passed through an imaging optical system (10) into a first optical path leading to a first imaging element (31) and a second optical path other than the first optical path; a second imaging element (27) that has a phase difference detection pixel for pupil-dividing and receiving the subject light traveling through the second optical path; and a light-blocking part (25) that includes an optical axis K2 of the second optical path and extends in an X direction crossing a Y direction of the pupil division and crossing the optical axis K2 of the second optical path.

Description

PHASE DIFFERENCE DETECTION DEVICE, LENS DEVICE, AND IMAGING DEVICE

The present invention relates to a phase difference detection device, a lens device, and an imaging device.

Patent Document 1 discloses a first imaging device that outputs a pair of image signals shifted in one direction for one subject optical image, and a second imaging device that captures the subject optical image through an imaging optical system including a focus lens. an optical element that causes part of the subject light incident on the imaging optical system to enter the imaging element, and causes the rest of the subject light excluding the part to enter the first imaging element; and the first imaging. a focus control unit that performs focus control of the focus lens based on the phase difference between the pair of image signals output from an element.

WO2016/038917

An embodiment according to the technology of the present disclosure provides a phase difference detection device, a lens device, and an imaging device that can suppress deterioration in ranging accuracy in a state of being largely out of focus.

A phase difference detection device according to the present invention includes a branching section that branches an optical path of subject light that has passed through an imaging optical system into a first optical path proceeding to a first imaging element and a second optical path other than the first optical path; a second imaging device having a phase difference detection pixel for pupil-dividing and receiving the subject light traveling along the optical path; and a light blocking portion extending in a direction intersecting the axis.

A lens device of the present invention includes the phase difference detection device and the imaging optical system.

An imaging device of the present invention includes the phase difference detection device and the first imaging element.

Another imaging device of the present invention is obtained by the phase difference detection device in which the imaging optical system includes a focus lens, a first imaging element that receives light traveling along the first optical path, and the phase difference detection device and a control unit that controls driving of the focus lens based on the phase difference information.

According to the present invention, it is possible to provide a phase difference detection device, a lens device, and an imaging device that can suppress deterioration in distance measurement accuracy when the focus is greatly out of focus.

1 is a schematic diagram showing a schematic configuration of an imaging device 100 according to an embodiment of the present invention; FIG. 3 is a diagram showing an example of a phase difference detection optical system 20 of the lens device 1; FIG. It is a figure which shows an example of the light-shielding part 25 seen from the direction of the optical axis K2. 9 is a graph showing an example of angular sensitivity characteristics of phase difference detection pixels in the second imaging element 27. FIG. FIG. 10 is a diagram showing an example of a ray angle range and a luminous flux 202 in the case of F1.4; FIG. 10 is a diagram showing an example of a ray angle range and a luminous flux 202 in the case of F2; FIG. 10 is a diagram showing an example of a ray angle range and a luminous flux 202 in the case of F2.8; It is a figure which shows an example of the ray angle range and the luminous flux 202 in the case of F4. It is a figure which shows an example of the ray angle range and the luminous flux 202 in the case of F8. FIG. 4 is a diagram showing an example of a light shielding portion 25 having a variable light shielding width;

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Imaging device 100 including the lens device 1 to which the phase difference detection device of the present invention is applied>
FIG. 1 is a schematic diagram showing an example of an imaging device 100 having a lens device 1 to which the phase difference detection device of the present invention is applied. This image pickup apparatus 100 is suitable for commercial use such as broadcasting or movies.

The imaging device 100 shown in FIG. 1 includes a lens device 1 and an imaging device main body 3 to which the lens device 1 is attached. FIG. 2 is a diagram showing an example of the phase difference detection optical system 20 of the lens device 1. As shown in FIG. The lens device 1 may be a lens device fixed to the imaging device main body 3 or an interchangeable lens device detachable from the imaging device main body 3 .

The lens device 1 includes an imaging optical system 10 including a plurality of lenses and a diaphragm 14. The plurality of lenses includes a focus lens 11, a zoom lens 12 for changing the focal length, a master lens group 15, and a blur correction lens 17 in the example of FIG. The focus lens 11, the zoom lens 12, the diaphragm 14, the master lens group 15, and the blur correction lens 17 are arranged in this order from the object side. It should be noted that FIG. 1 is for illustration purposes only, and the imaging optical system 10 does not consist only of the illustrated lenses, but may include a plurality of lenses (not illustrated).

The focus lens 11 is supported so as to be movable parallel to the optical axis K1 of the imaging optical system 10 . The blur correction lens 17 is movably supported within a plane perpendicular to the optical axis K1 of the imaging optical system 10 . Note that the optical axis K1 of the imaging optical system 10 is a virtual ray representing a light beam passing through the imaging optical system 10, and includes, for example, the focus lens 11, the zoom lens 12, the master lens group 15, and the blur correction. is the axis of rotational symmetry of the lens 17 for use.

The lens device 1 further includes a beam splitter 16 including a reflecting surface 16a, a phase difference detection optical system 20, a second imaging element 27, a control section 28, and a driving mechanism 29. The drive mechanism 29 controls the focus position by driving the focus lens 11 under the control of the control unit 28 and moving the focus lens 11 parallel to the optical axis K1. The drive mechanism 29 is configured by a motor such as a stepping motor, for example.

The beam splitter 16 is arranged between the master lens group 15 and the blur correction lens 17 on the optical axis K1. The beam splitter 16 splits the optical path of the subject light that has passed through the imaging optical system 10 into a first optical path leading to the first imaging element 31 and a second optical path other than the first optical path (an optical path leading to the mirror 22). It is an example of a branch part.

The beam splitter 16 transmits part of the subject light (for example, 80% of the subject light) that has entered the imaging optical system 10 and passed through the diaphragm 14 and the master lens group 15 as it is. (For example, 20% of the subject light) is reflected by the reflecting surface 16a in a direction intersecting the optical axis K1.

The position of the beam splitter 16 is not limited to that shown in FIG. It should be placed in front. A half mirror may also be used as the beam splitter 16 . A half mirror is obtained, for example, by forming a metal thin film on glass.

The phase difference detection optical system 20 is an optical system that guides subject light reflected by the beam splitter 16 to the second imaging device 27 . Specifically, the phase difference detection optical system 20 includes a condensing lens 21 , a mirror 22 , a condensing lens 23 , a diaphragm 24 , a light blocking section 25 and a condensing lens 26 .

The condenser lens 21 is arranged on the optical path of the light reflected by the reflecting surface 16 a of the beam splitter 16 and allows the light to pass through and enter the mirror 22 . The mirror 22 is arranged on the optical path of the subject light that has passed through the condensing lens 21 , and reflects this light to enter the condensing lens 23 . The condenser lens 23 is arranged on the optical path of the subject light reflected by the mirror 22 , and allows the light to pass through and enter the diaphragm 24 .

The diaphragm 24 is arranged on the optical path of the subject light that has passed through the condenser lens 23 , adjusts the light amount of this light, and causes the adjusted light amount to enter the condenser lens 26 . The diaphragm 24 is used when subject light incident on the second image sensor 27 is narrowed further than the diaphragm of the diaphragm 14 . For example, if the aperture of the diaphragm 14 is large, such as F1.4, and the object light that has passed through the diaphragm 14 is incident on the second imaging element 27 as it is, the phase difference cannot be calculated. A control is performed to further narrow down the subject light that is emitted by the diaphragm 24 .

The light blocking section 25 is provided at the same position as the diaphragm 24 and blocks part of the subject light passing through the diaphragm 24 . The configuration of the light shielding portion 25 will be described later. The condenser lens 26 is arranged on the optical path of the subject light that has passed through the diaphragm 24 , and allows the light to pass through and enter the second image sensor 27 .

The phase difference detection optical system 20 is configured so that subject light reflected by the beam splitter 16 is imaged twice. For example, the first imaging of the subject light is performed at a position between the condenser lens 21 and the mirror 22 , and the second imaging of the subject light is performed at the second imaging device 27 . As a result, even if the beam splitter 16 is not provided at the position of the diaphragm 14, for example, a position is created in the phase difference detection optical system 20 through which all the light beams pass, and the diaphragm 24 is provided at that position to efficiently adjust the amount of light. be able to.

In FIG. 2, the light from the subject once forms an image at the first image forming position, spreads again, passes through different positions at the positions of the diaphragm 24 and the light shielding portion 25, and reaches the second image sensor 27 again. A second image is formed at the position of .

Note that the mirror 22 of the phase difference detection optical system 20 may be removed and the light reflected by the beam splitter 16 may be directly incident on the condenser lens 23 .

The second imaging element 27 is an image-plane phase-difference imaging element having phase-difference detection pixels that receive the subject light incident from the condenser lens 26, that is, the subject light traveling along the second optical path, with pupil division. The second imaging element 27 outputs a pair of image signals shifted in one direction with respect to one subject optical image formed by the imaging optical system 10 .

For example, the second imaging element 27 receives one of a pair of luminous fluxes that have passed through two different portions aligned in one direction in the pupil region of the imaging optical system 10, and detects a signal corresponding to the amount of received light. and pixels for receiving the other of the pair of light beams and detecting a signal corresponding to the amount of light received are arranged two-dimensionally over the entire light receiving surface. In FIG. 2, light coming from different directions is incident on the second imaging element 27 . FIG. 2 shows how light passing through the opposite side of the light shielding portion 25 is incident on the second imaging element 27 from different directions. Phase difference information can be obtained by providing a light shielding film in the pixels of the second imaging element 27 and receiving only one of the lights from different directions.

The control unit 28 calculates phase difference information based on a pair of image signals output from the second imaging element 27, and calculates a defocus amount (out-of-focus amount) based on the calculated phase difference information. Then, the control unit 28 performs focus adjustment of the imaging optical system 10 by controlling driving of the focus lens 11 by the driving mechanism 29 based on the calculated defocus amount.

The control unit 28 is composed of a processor and ROM (Read Only Memory) memory such as RAM (Random Access Memory) and flash memory. When using flash memory, the stored program can be rewritten as needed. The control unit 28 implements each function by executing a program including a phase difference detection program stored in an internal ROM.

The imaging device main body 3 includes a first imaging device 31 such as a CMOS (Complementary Metal Oxide Semiconductor) type image sensor or a CCD (Charge Coupled Device) type image sensor arranged on the optical axis K1 of the lens device 1, and a first imaging device. and an image processing unit 32 for processing an image signal obtained by capturing an optical image of a subject by the element 31 to generate captured image data.

In FIG. 2, the condensing lens 23 is omitted in order to simply show the luminous flux of the subject light. In FIG. 2, a luminous flux 201 simply represents a luminous flux of subject light that is reflected by the reflecting surface 16 a of the beam splitter 16 and enters the mirror 22 . A luminous flux 202 simply represents a luminous flux of subject light that is reflected by the mirror 22 and enters the second imaging element 27 . An optical axis K2 is the optical axis of the light flux 202 (a representative virtual light ray). For example, the optical axis K2 is the axis of rotational symmetry of the condenser lens 23 and the condenser lens 26 .

The light branched from the first optical path and proceeding to the second optical path once forms a real image at a certain position (first imaging position P1) on the second optical path. The light that has formed a real image further travels along the second optical path, and spreads further as shown in FIG. This spread light is further condensed by an optical system including a condensing lens 26 and the like, and formed again as a real image on the second imaging element 27 (second imaging position P2). Since the light that forms an image on the second imaging element 27 comes from different directions, each pixel of the second imaging element 27 is pupil-divided by a light shielding film so that only light from a specific direction can be detected. can do.

The direction of the optical axis K2 (horizontal direction in FIG. 2) is the Z direction, the direction of pupil division in the second image sensor 27 (vertical direction in FIG. 2) is the Y direction, and the direction intersecting the Z and Y directions ( 2) is the X direction. It should be noted that the term "intersection" as used herein includes orthogonality.

The light shielding part 25 is a member that includes the optical axis K2 of the second optical path and extends in the X direction. Including the optical axis K2 means including (passing through) at least one point of the optical axis K2. Although FIG. 2 does not show that the light flux 202 is blocked by the aperture 24 and the light shielding section 25, in reality, the light flux 202 is narrowed by the aperture 24 and separated in the Y direction by the light shielding section 25 for the second imaging. It is incident on element 27 .

<Light blocking portion 25 viewed from the direction of optical axis K2>
FIG. 3 is a diagram showing an example of the light blocking portion 25 viewed from the direction of the optical axis K2. In FIG. 3, a straight line 301 is a straight line that intersects the Y direction (direction of pupil division) and the optical axis K2. The light shielding portion 25 has a symmetrical shape with respect to the straight line 301 when viewed from the direction of the optical axis K2. Thereby, the light flux 202 can be evenly separated in the Y direction. Note that the shape of the portion of the light blocking portion 25 that does not block the light flux 202 does not have to be symmetrical with respect to the straight line 301 . The fact that the straight line 301 of the light shielding portion 25 intersects the Y direction and the optical axis K2 includes the fact that the straight line 301 of the light shielding portion 25 is perpendicular to the Y direction and the optical axis K2. The straight line 301 of the light shielding portion 25 is most preferably perpendicular to the Y direction and the optical axis K2, but it is not limited to crossing at exactly 90°.

<Angular Sensitivity Characteristics of Phase Difference Detection Pixels in Second Image Sensor 27>
FIG. 4 is a graph showing an example of angular sensitivity characteristics of phase difference detection pixels in the second imaging element 27. As shown in FIG. An angular sensitivity characteristic 41 indicated by a dashed-dotted line indicates the characteristic of the sensitivity of receiving light with respect to the incident angle of one of a pair of light beams pupil-divided in the Y direction in the phase difference detection pixel of the second imaging element 27. ing. As described above, the phase difference detection pixels in the second image sensor 27 perform pupil division by means of a light shielding film formed in the pixels.

An angular sensitivity characteristic 42 indicated by a chain double-dashed line represents the sensitivity characteristic of light reception with respect to the incident angle of the other of a pair of light beams pupil-divided in the Y direction in the phase difference detection pixel of the second imaging element 27. showing. The angular sensitivity characteristic 40 indicates, as a reference, the characteristic of the light receiving sensitivity of the first imaging device 31 with respect to the incident angle of light rays.

As shown in the

angular sensitivity characteristics

41 and 42, the peaks of the angular sensitivity characteristics of the pair of light beams pupil-divided in the Y direction are shifted. By realizing such

angular sensitivity characteristics

41 and 42 with the light shielding film in the phase difference detection pixel of the second imaging element 27, the control unit 28 controls the phase difference pixel having the angular sensitivity characteristic 41 and the angular sensitivity characteristic 42 The defocus amount can be derived by performing a correlation operation on the signals of the phase difference pixels having .

Here, when the focus is greatly out of focus, it becomes difficult to calculate a defocus amount with high reliability from the result of the correlation calculation. In FIG. 4, when the focus is greatly out of focus, the peak of the incident angle on the minus side in the angular sensitivity characteristic 41 is relatively lower than the sensitivity near the incident angle of 0°, and the angular sensitivity characteristic 42 is the same. In such a case, the result of the correlation calculation becomes unreliable, and the conventional configuration reduces the accuracy of distance measurement. On the other hand, in the image pickup apparatus 100 , by blocking part of the subject light incident on the second image pickup element 27 with the light shielding section 25 , such a decrease in distance measurement accuracy is suppressed.

<Light ray angle range and luminous flux 202 at each F value>
FIG. 5 is a diagram showing an example of the ray angle range and the luminous flux 202 in the case of F1.4. A light beam angle range 51 is an angle range of the light flux 202 incident on the second imaging element 27 assuming that the light shielding portion 25 is not provided. When the F-number of the optical system through which the light beam 202 incident on the second imaging element 27 passes is F1.4, the light beam angle range 51 is as shown in FIG. 5, for example.

The F value of the optical system through which the light flux 202 incident on the second imaging element 27 passes is, for example, the F value of the aperture 14 of the imaging optical system 10 and the F value of the aperture 24 of the phase difference detection optical system 20. It is the maximum F value among them.

A shaded range 52 indicated by oblique lines is an angular range of rays of the light flux 202 incident on the second imaging element 27 that are blocked by the provision of the light shielding section 25 . As shown in FIG. 3, the light blocking portion 25 extends in the X direction and has a symmetrical shape centered on a straight line 301 that intersects the Y direction (direction of pupil division) and the optical axis K2. It becomes part of the center of the angular range 51 .

As a result, the central ray of the ray angle range 51 in which the degree of overlap of the

angular sensitivity characteristics

41 and 42 is large can be blocked. Therefore, even when the image is largely out of focus, the blurring of each of the pair of images obtained by the second imaging element 27 can be reduced, thereby suppressing a decrease in distance measurement accuracy.

In FIG. 5, the case where the F value of the optical system through which the light beam 202 incident on the second imaging element 27 passes is F1.4 has been described, but as shown in FIGS. Control may be performed to adjust the light shielding width (the width in the Y direction) of the light shielding portion 25 based on this F value. The configuration of the light shielding portion 25 capable of adjusting the light shielding width will be described later (see FIG. 10 and the like).

FIG. 6 is a diagram showing an example of the ray angle range and the luminous flux 202 in the case of F2. As shown in FIG. 6, when the F value of the optical system through which the light beam 202 incident on the second image pickup device 27 passes is F2, the light beam 202 is larger than when the F value is F1.4 (FIG. 5). The diameter becomes smaller and the ray angle range 51 becomes narrower. On the other hand, the control unit 28 narrows the light shielding range 52 by performing control to narrow the width of the light shielding unit 25 in the Y direction compared to the case where the F value is F1.4.

FIG. 7 is a diagram showing an example of the ray angle range and the luminous flux 202 in the case of F2.8. As shown in FIG. 7, when the F-number of the optical system through which the light flux 202 incident on the second image sensor 27 passes is F2.8, the light flux 202 is larger than when the F-number is F2 (FIG. 6). The diameter becomes smaller and the ray angle range 51 becomes narrower. In response to this, the control unit 28 narrows the light shielding range 52 by performing control to narrow the width of the light shielding unit 25 in the Y direction compared to when the F value is F2.

FIG. 8 is a diagram showing an example of the ray angle range and the luminous flux 202 in the case of F4. As shown in FIG. 8, when the F value of the optical system through which the light beam 202 incident on the second image pickup device 27 passes is F4, the light beam 202 is larger than when the F value is F2.8 (FIG. 7). The diameter becomes smaller and the ray angle range 51 becomes narrower. On the other hand, the control unit 28 narrows the light shielding range 52 by controlling the width of the light shielding unit 25 in the Y direction to be narrower than when the F value is F2.8.

FIG. 9 is a diagram showing an example of the ray angle range and the luminous flux 202 in the case of F8. As shown in FIG. 9, when the F value of the optical system through which the light beam 202 incident on the second imaging element 27 passes is F8, the diameter of the light beam 202 is As a result, the ray angle range 51 also becomes narrower. On the other hand, the control unit 28 narrows the light shielding range 52 by controlling the width of the light shielding unit 25 in the Y direction to be narrower than when the F value is F4.

When the F-number of the optical system through which the light flux 202 incident on the second imaging element 27 passes is large (for example, F11), the control unit 28 sets the width of the light shielding unit 25 in the Y direction to 0, that is, the light shielding unit 25 The light flux 202 may not be blocked.

As shown in FIGS. 5 to 9, the control unit 28 blocks light in accordance with the opening amounts (F values) of the

diaphragms

14, 24 included in the optical system through which the subject light incident on the second image sensor 27 passes. The light shielding width of the portion 25 may be adjusted. Specifically, the control unit 28 adjusts the light shielding width of the light shielding unit 25 to be narrower as the opening amounts of the

diaphragms

14 and 24 are smaller (as the F value is larger).

As a result, the light shielding range 52 can be narrowed by following the light beam angle range 51, which becomes narrower as the opening amounts of the

diaphragms

14 and 24 become smaller. Therefore, it is possible to prevent difficulty in calculating the phase difference due to insufficient amount of subject light in the second imaging element 27 . When the opening amounts of the

diaphragms

14 and 24 are small, the blurring of the pair of images obtained by the second image pickup device 27 is small, so that narrowing the light shielding width of the light shielding portion 25 has little effect on distance measurement accuracy. .

<Light shielding part 25 with variable light shielding width>
FIG. 10 is a diagram showing an example of the light shielding portion 25 having a variable light shielding width. For example, the light shielding part 25 is rotatable around a rotation axis 60 parallel to the Z direction. Further, the light shielding section 25 has a plurality of light shielding plates 61-65. The light shielding plates 61 to 65 are arranged in the circumferential direction of a circle centered on the rotation axis 60 and extend in the radial direction of the circle centered on the rotation axis 60 .

In addition, the light shielding plates 61 to 65 have different widths (lengths in the circumferential direction of circles centered on the rotation axis 60). Specifically, the width of the light shielding plate 61 is the widest, and the width of the light shielding plate 62, the light shielding plate 63, the light shielding plate 64, and the light shielding plate 65 is narrowed in this order.

Also, the light shielding part 25 has an annular outer peripheral part 66 centered on the rotation shaft 60 , and the light shielding plates 61 to 65 are fixed inside the outer peripheral part 66 . The light shielding portion 25 is arranged such that the optical axis K2 passes between the rotating shaft 60 and the outer peripheral portion 66. As shown in FIG.

The rotation of the light shielding part 25 is performed, for example, by the control part 28 controlling a driving mechanism (for example, a motor such as a stepping motor) (not shown). The control unit 28 controls the rotation angle of the light shielding unit 25 according to the F-number of the optical system through which the light flux 202 incident on the second imaging element 27 has passed.

For example, when the F value is F1.4 (see FIG. 5), the control unit 28 controls the rotation angle of the light shielding unit 25 so that the center of the light shielding plate 61 coincides with the optical axis K2, as shown in FIG. do. Further, when the F value is F2 (see FIG. 6), the control section 28 controls the rotation angle of the light shielding section 25 so that the center of the light shielding plate 62 coincides with the optical axis K2.

Further, when the F number is F2.8 (see FIG. 7), the control unit 28 controls the rotation angle of the light shielding unit 25 so that the center of the light shielding plate 63 coincides with the optical axis K2. Further, when the F number is F4 (see FIG. 8), the control unit 28 controls the rotation angle of the light shielding unit 25 so that the center of the light shielding plate 64 coincides with the optical axis K2. Further, when the F value is F8 (see FIG. 9), the control unit 28 controls the rotation angle of the light shielding unit 25 so that the center of the light shielding plate 65 coincides with the optical axis K2.

When the F-number is larger than F8 (for example, F11), the control unit 28 rotates the light blocking plate 25 so that none of the light blocking plates 61 to 65 block the light flux 202 centering on the optical axis K2. You can control the angle.

With the configuration shown in FIG. 10, the width of the portion of the light shielding portion 25 that shields the light flux 202 can be controlled by rotating the light shielding portion 25 . However, the light-shielding portion 25 with a variable light-shielding width is not limited to the example shown in FIG. 10, and may be configured by, for example, a non-transmissive region of a liquid crystal panel whose transmissive region can be changed by an applied voltage. Further, the diaphragm 24 can be configured by a liquid crystal panel, and in this case, the diaphragm 24 and the light blocking section 25 may be configured by one liquid crystal panel.

In this manner, the imaging apparatus 100 uses the beam splitter 16 (branching beam splitter 16) that splits the optical path of the subject light that has passed through the imaging optical system 10 into a first optical path proceeding to the first imaging element 31 and a second optical path other than the first optical path. part), a second imaging element 27 having phase difference detection pixels for pupil-dividing and receiving subject light traveling on the second optical path, an optical axis K2 of the second optical path, intersecting the Y direction of the pupil division, and and a light blocking portion 25 extending in the X direction intersecting the optical axis K2 of the second optical path.

As a result, of the subject light incident on the second imaging element 27, the portion extending in the X direction through the optical axis K2 is blocked, and blurring of the image in a state of being largely out of focus can be reduced. Therefore, even when the focus is greatly out of focus, it is possible to correctly calculate the phase difference based on the pair of image signals output from the second imaging element 27, thereby suppressing a decrease in distance measurement accuracy.

The imaging apparatus 100 also includes a condenser lens 21 that forms an image of the subject light at a position between the beam splitter 16 (branching portion) and the second imaging element 27, and causes the second imaging element 27 to form an image of the subject light again. , 23 and 26 (optical system), and the light shielding unit 25 is positioned between the imaging position of the subject light between the beam splitter 16 (branching unit) and the second imaging element 27 and the second imaging element 27. is provided. That is, the light shielding portion 25 is provided at the same position as the position suitable for providing the diaphragm 24 in the second optical path.

Thereby, for example, even if the beam splitter 16 is not provided at the position of the diaphragm 14, a position through which all rays pass can be created in the phase difference detection optical system 20, and the light blocking section 25 can be provided at that position. Therefore, the degree of freedom in designing the imaging optical system 10 can be improved.

Also, by making the light shielding width of the light shielding section 25 adjustable, it is possible to shield part of the subject light according to the diameter of the subject light incident on the second imaging element 27 . For example, the control unit 28 adjusts the light shielding width of the light shielding unit 25 according to the opening amount (F value) of the apertures (apertures 14 and 24) included in the optical system through which the subject light incident on the second imaging element 27 passes. do. Specifically, the control unit 28 adjusts the light shielding width of the light shielding unit 25 so that the smaller the opening amount of the diaphragm (the larger the F number), the narrower the light shielding width. As a result, it is possible to prevent difficulty in distance measurement due to insufficient amount of subject light in the second image sensor 27 .

<Modification 1>
The control unit 28 may adjust the light shielding width of the light shielding unit 25 based on the focal length of the imaging optical system 10 depending on the type of lens. Specifically, in the case of a lens in which the open f-number changes with the zoom magnification, the control unit 28 adjusts the light shielding width of the light shielding unit 25 based on the drive information of the zoom lens 12 as the focal length of the imaging optical system 10 increases. adjust so that it is narrower. As a result, it is possible to prevent difficulty in distance measurement due to insufficient amount of subject light in the second image sensor 27 .

Also, the control unit 28 may adjust the light shielding width of the light shielding unit 25 based on both the opening amount of the diaphragm and the focal length of the imaging optical system 10 . For example, the memory provided in the imaging device 100 stores correspondence information indicating the light shielding width of the light shielding unit 25 for each combination of the opening amount of the diaphragm and the focal length of the imaging optical system 10, and the control unit 28 The light blocking width of the light blocking portion 25 is adjusted using this correspondence information.

<Modification 2>
Although the configuration in which the phase difference detection device of the present invention is applied to the lens device 1 has been described, the phase difference detection device of the present invention can also be applied to the imaging device main body 3 . For example, in the configuration shown in FIG. 1, a configuration in which the beam splitter 16, the phase difference detection optical system 20, and the second imaging device 27 are provided in the imaging device main body 3 may be employed. In this case, the beam splitter 16 is provided closer to the subject than the first imaging element 31 is.

Furthermore, a configuration in which the control unit 28 is provided in the imaging device main body 3 may be employed. Further, when the control unit 28 is provided in the imaging device main body 3 and the lens device 1 is an interchangeable type, the control unit 28 receives information on the focal length of the lens device 1 attached to the imaging device main body 3 from the lens device 1. The light shielding width of the light shielding section 25 may be adjusted based on the focal length of the imaging optical system 10 after obtaining the focal length.

As explained above, the following matters are disclosed in this specification.

(1)
a branching unit that branches an optical path of subject light that has passed through the imaging optical system into a first optical path proceeding to a first imaging element and a second optical path other than the first optical path;
a second imaging element having a phase difference detection pixel for pupil-dividing and receiving the subject light traveling along the second optical path;
a light shielding portion that includes the optical axis of the second optical path and extends in a direction that intersects the direction of pupil division and intersects the optical axis of the second optical path;
A phase difference detection device comprising:

(2)
(1) The phase difference detection device according to
the second optical path includes an optical system that forms an image of the subject light at a position between the branching portion and the second imaging element, and forms an image of the subject light again with the second imaging element;
The light shielding part is between the position and the second imaging element,
Phase difference detector.

(3)
(2) The phase difference detection device according to,
The light shielding unit adjusts the amount of light of the subject light incident on the second imaging element and is located at a position where the stop provided at the position overlaps with the optical axis of the second optical path.
Phase difference detector.

(4)
The phase difference detection device according to any one of (1) to (3),
The width of the light shielding portion in the direction of the pupil division is adjustable,
Phase difference detector.

(5)
(4) The phase difference detection device according to,
The width is adjusted based on the opening amount of a diaphragm that adjusts the amount of light of the subject light incident on the second imaging element.
Phase difference detector.

(6)
(5) The phase difference detection device according to
The width is adjusted to be narrower as the opening amount is smaller.
Phase difference detector.

(7)
The phase difference detection device according to any one of (4) to (6),
The imaging optical system has a variable focal length,
The width is adjusted based on the focal length of the imaging optical system,
Phase difference detector.

(8)
(7) The phase difference detection device according to,
The width is adjusted to be narrower as the focal length is longer.
Phase difference detector.

(9)
The phase difference detection device according to any one of (1) to (8),
The light-shielding portion of the light-shielding portion has a symmetrical shape centered on a straight line that includes the optical axis and intersects the direction of the pupil division and the optical axis.
Phase difference detector.

(10)
a phase difference detection device according to any one of (1) to (9);
the imaging optical system;
A lens device comprising:

(11)
a phase difference detection device according to any one of (1) to (9);
the first imaging device;
An imaging device comprising:

(12)
The phase difference detection device according to any one of (1) to (9), wherein the imaging optical system includes a focus lens;
a first imaging element that receives light traveling along the first optical path;
a control unit that controls driving of the focus lens based on the phase difference information obtained by the phase difference detection device;
An imaging device comprising:

Various embodiments have been described above with reference to the drawings, but it goes without saying that the present invention is not limited to such examples. It is obvious that a person skilled in the art can conceive of various modifications or modifications within the scope described in the claims, and these also belong to the technical scope of the present invention. Understood. Moreover, each component in the above embodiments may be combined arbitrarily without departing from the gist of the invention.

This application is based on a Japanese patent application (Japanese Patent Application No. 2021-014008) filed on January 29, 2021, the contents of which are incorporated herein by reference.

By applying the phase difference detection device of the present invention to an imaging device for broadcasting, it is possible to suppress a decrease in distance measurement accuracy when the focus is greatly out of focus.

1 lens device 3 imaging device body 10 imaging optical system 11 focus lens 12

zoom lens

14, 24 diaphragm 15 master lens group 16 beam splitter 16a reflecting surface 17 blur correction lens 20 phase difference detection

optical system

21, 23, 26 condenser lens 22 mirror 25 light shielding unit 27 second image sensor 28 control unit 29 drive mechanism 31 first image sensor 32 image processing unit 40 to 42 angle sensitivity characteristics 51 light beam angle range 52 light shielding range 60 rotating shaft 61 to 65 light shielding plate 66 outer peripheral portion 100

Imaging device

201, 202 Light beam 301 Straight line K1, K2 Optical axis P1 First imaging position P2 Second imaging position

Claims

a branching unit that branches an optical path of subject light that has passed through the imaging optical system into a first optical path proceeding to a first imaging element and a second optical path other than the first optical path;
a second imaging device having a phase difference detection pixel that receives the subject light that travels along the second optical path by dividing the pupil and receiving the light;
a light shielding portion that includes the optical axis of the second optical path and extends in a direction that intersects the direction of pupil division and intersects the optical axis of the second optical path;
A phase difference detection device comprising:
The phase difference detection device according to claim 1,
the second optical path includes an optical system that forms an image of the subject light at a position between the branching portion and the second imaging element, and forms an image of the subject light again with the second imaging element;
The light shielding part is between the position and the second imaging element,
Phase difference detector.
The phase difference detection device according to claim 2,
The light shielding unit adjusts the amount of light of the subject light incident on the second imaging element and is located at a position overlapping an aperture provided at the position on the optical axis of the second optical path,
Phase difference detector.
The phase difference detection device according to any one of claims 1 to 3,
The width of the light shielding part in the direction of pupil division is adjustable.
Phase difference detector.
The phase difference detection device according to claim 4,
The width is adjusted based on the opening amount of a diaphragm that adjusts the amount of light of the subject light incident on the second imaging element,
Phase difference detector.
The phase difference detection device according to claim 5,
The width is adjusted to be narrower as the opening amount is smaller.
Phase difference detector.
The phase difference detection device according to any one of claims 4 to 6,
The imaging optical system has a variable focal length,
the width is adjusted based on the focal length of the imaging optical system;
Phase difference detector.
The phase difference detection device according to claim 7,
The width is adjusted to be narrower as the focal length is longer.
Phase difference detector.
The phase difference detection device according to any one of claims 1 to 8,
The light-shielding portion of the light-shielding portion has a symmetrical shape centered on a straight line that includes the optical axis and intersects the direction of the pupil division and the optical axis.
Phase difference detector.
A phase difference detection device according to any one of claims 1 to 9;
the imaging optical system;
A lens device comprising:
A phase difference detection device according to any one of claims 1 to 9;
the first imaging element;
An imaging device comprising:
A phase difference detection device according to any one of claims 1 to 9, wherein the imaging optical system includes a focus lens;
a first imaging element that receives light traveling along the first optical path;
a control unit that controls driving of the focus lens based on the phase difference information obtained by the phase difference detection device;
An imaging device comprising: