Phase difference detection device, lens device, and imaging device

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

[Technical Field]

[0001] The present invention relates to a phase difference detection device, a lens device, and an imaging device. [Background technology]

[0002] Patent Document 1 describes a focus control device that includes a first image sensor that outputs a pair of image signals that are shifted in one direction for one subject light image, an optical element that causes a portion of subject light that enters an imaging optical system including a focus lens to be incident on a second image sensor that captures the subject light image through the imaging optical system including a focus lens, and causes the remainder of the subject light, excluding the portion, to be incident on the first image sensor, and 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 the first image sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2016 / 038917 Summary of the Invention

[0004] One embodiment of the technique of the present disclosure provides a phase difference detection device, a lens device, and an imaging device that can suppress a decrease in distance measurement accuracy when the object is significantly out of focus. [Means for solving the problem]

[0005] The phase difference detection device of the present invention includes a branching section that branches the optical path of subject light that has passed through an imaging optical system into a first optical path that proceeds to a first imaging element and a second optical path other than the first optical path, a second imaging element having phase difference detection pixels that receive the subject light that proceeds along the second optical path by pupil-splitting, and a light-shielding section that includes the optical axis of the second optical path and extends in a direction that intersects the direction of the pupil division and also intersects the optical axis of the second optical path.

[0006] A lens device of the present invention includes the above phase difference detection device and the above imaging optical system.

[0007] An imaging device of the present invention includes the above phase difference detection device and the above first imaging element.

[0008] Another imaging device of the present invention includes the phase difference detection device in which the imaging optical system is equipped with a focus lens, a first imaging element that receives light traveling through the first optical path, and a control unit that controls driving of the focus lens based on phase difference information obtained by the phase difference detection device. [Effects of the Invention]

[0009] 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 a decrease in distance measurement accuracy when the object is significantly out of focus. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing a general configuration of an imaging device 100 according to an embodiment of the present invention. [Figure 2] 2 is a diagram showing an example of a phase difference detection optical system 20 of the lens device 1. FIG. [Figure 3] 10 is a diagram showing an example of a light blocking portion 25 as viewed from the direction of an optical axis K2. FIG. [Figure 4] 10 is a graph showing an example of the angle sensitivity characteristics of a phase difference detection pixel in the second imaging element 27. [Figure 5] 10 is a diagram showing an example of a light beam angle range and a light beam 202 in the case of F1.4. [Figure 6] 10 is a diagram showing an example of the ray angle range and the light beam 202 in the case of F2. [Figure 7] 10 is a diagram showing an example of a light beam angle range and a light beam 202 in the case of F2.8. [Figure 8] 10 is a diagram showing an example of a ray angle range and a light beam 202 in the case of F4. [Figure 9]FIG. 10 is a diagram showing an example of the ray angle range and the light beam 202 in the case of F8. [Figure 10] 10 is a diagram showing an example of a light-shielding portion 25 whose light-shielding width is variable. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] <Image capture device 100 equipped with lens device 1 employing the phase difference detection device of the present invention> 1 is a schematic diagram showing an example of an imaging device 100 equipped with a lens device 1 to which a phase difference detection device of the present invention is applied. This imaging device 100 is suitable for professional use, such as for broadcasting or film.

[0013] 1 includes a lens device 1 and an imaging device body 3 to which the lens device 1 is attached. Fig. 2 is a diagram showing an example of a phase difference detection optical system 20 of the lens device 1. The lens device 1 may be a lens device fixed to the imaging device body 3, or may be an interchangeable lens device that is detachable from the imaging device body 3.

[0014] The lens device 1 includes an imaging optical system 10 that includes multiple lenses and an aperture 14. In the example of FIG. 1, these multiple lenses include a focus lens 11, a zoom lens 12 for changing the focal length, a master lens group 15, and a motion compensation lens 17. The focus lens 11, the zoom lens 12, the aperture 14, the master lens group 15, and the motion compensation lens 17 are arranged in this order from the subject side. Note that FIG. 1 is for illustrative purposes only, and the lens configuration of the imaging optical system 10 does not have to consist only of the lenses shown in the figure, and may include multiple lenses that are not shown.

[0015] The focus lens 11 is supported so as to be movable parallel to the optical axis K1 of the imaging optical system 10. The motion compensation lens 17 is supported so as to be movable within a plane perpendicular to the optical axis K1 of the imaging optical system 10. The optical axis K1 of the imaging optical system 10 is a virtual light ray that represents a light beam passing through the imaging optical system 10, and is, for example, the axis of rotational symmetry of the focus lens 11, zoom lens 12, master lens group 15, and motion compensation lens 17.

[0016] The lens device 1 further includes a beam splitter 16 including a reflecting surface 16a, a phase difference detection optical system 20, a second image sensor 27, a control unit 28, and a drive mechanism 29. The drive mechanism 29 drives the focus lens 11 under the control of the control unit 28 to move the focus lens 11 parallel to the optical axis K1, thereby controlling the focus position. The drive mechanism 29 is configured by a motor such as a stepping motor.

[0017] Beam splitter 16 is disposed on optical axis K1 between master lens group 15 and image blur correction lens 17. Beam splitter 16 is an example of a branching unit that branches the optical path of subject light that has passed through imaging optical system 10 into a first optical path that proceeds to first image sensor 31 and a second optical path other than the first optical path (optical path that proceeds to mirror 22).

[0018] The beam splitter 16 transmits a portion of the subject light (e.g., 80% of the subject light) that enters the imaging optical system 10 and passes through the aperture 14 and the master lens group 15, and reflects the remainder (e.g., 20% of the subject light) from the reflecting surface 16a in a direction intersecting the optical axis K1.

[0019] The position of the beam splitter 16 is not limited to that shown in Fig. 1, and it may be located behind the lens (e.g., focus lens 11) that is closest to the subject in the imaging optical system 10 on the optical axis K1 and in front of the image blur correction lens 17. A half mirror may also be used as the beam splitter 16. A half mirror can be obtained, for example, by forming a thin metal film on glass.

[0020] The phase difference detection optical system 20 is an optical system that guides the subject light reflected by the beam splitter 16 to the second image sensor 27. Specifically, the phase difference detection optical system 20 includes a condenser lens 21, a mirror 22, a condenser lens 23, an aperture 24, a light blocking unit 25, and a condenser lens 26.

[0021] The condenser lens 21 is disposed on the optical path of the light reflected by the reflecting surface 16a of the beam splitter 16, and passes this light so that it is incident on the mirror 22. The mirror 22 is disposed on the optical path of the subject light that has passed through the condenser lens 21, and reflects this light so that it is incident on the condenser lens 23. The condenser lens 23 is disposed on the optical path of the subject light that has been reflected by the mirror 22, and passes this light so that it is incident on the diaphragm 24.

[0022] Aperture 24 is disposed on the optical path of the subject light that has passed through condenser lens 23, adjusts the amount of this light, and causes the light with the adjusted amount to enter condenser lens 26. Aperture 24 is used when the subject light that enters second image sensor 27 is narrowed down more than the aperture of aperture 14. For example, when the aperture of aperture 14 is large, such as F1.4, and it is difficult to calculate the phase difference if the subject light that has passed through aperture 14 is allowed to enter second image sensor 27 as is, control is performed to further narrow down the subject light that enters second image sensor 27 using aperture 24.

[0023] The light blocking section 25 is provided at the same position as the diaphragm 24, and blocks a portion of the subject light passing through the diaphragm 24. The configuration of the light blocking section 25 will be described later. The condenser lens 26 is disposed on the optical path of the subject light that has passed through the diaphragm 24, and passes this light so that it is incident on the second image sensor 27.

[0024] The phase difference detection optical system 20 is configured so that the subject light reflected by the beam splitter 16 forms an image twice. For example, the first image of the subject light is formed at a position between the condenser lens 21 and the mirror 22, and the second image of the subject light is formed at the second image sensor 27. As a result, even if the beam splitter 16 is not provided at the position of the aperture 14, for example, it is possible to efficiently adjust the amount of light by creating a position in the phase difference detection optical system 20 through which all light rays pass and providing the aperture 24 at that position.

[0025] In Figure 2, light from the subject first forms an image at the first imaging position, then spreads out again, passes through different positions at the positions of the aperture 24 and the light blocking portion 25, and forms a second image again at the position of the second image sensor 27.

[0026] It is also possible to eliminate the mirror 22 of the phase difference detection optical system 20 and configure the light reflected by the beam splitter 16 to be directly incident on the condenser lens 23 .

[0027] The second image sensor 27 is an image plane phase difference image sensor having phase difference detection pixels that receive the subject light incident from the condenser lens 26, i.e., the subject light traveling along the second optical path, by pupil division. The second image sensor 27 outputs a pair of image signals that are shifted in one direction for one subject light image formed by the imaging optical system 10.

[0028] For example, the second image sensor 27 has pairs of pixels arranged two-dimensionally across the entire light receiving surface, each pixel receiving one of a pair of light beams that have passed through two different portions aligned in one direction in the pupil region of the imaging optical system 10 and detecting a signal corresponding to the amount of received light, and each pixel receiving the other of the pair of light beams and detecting a signal corresponding to the amount of received light. In FIG. 2, light coming from different directions is incident on the second image sensor 27. FIG. 2 shows how light passing through opposite sides of the light shielding portion 25 enters the second image sensor 27 from different directions. By providing a light shielding film within the pixels of the second image sensor 27 and receiving only one of the light beams coming from different directions, phase difference information can be obtained.

[0029] The control unit 28 calculates phase difference information based on the pair of image signals output from the second imaging element 27, and calculates a defocus amount (amount of out-of-focus) based on the calculated phase difference information. Then, the control unit 28 controls the driving of the focus lens 11 by the driving mechanism 29 based on the calculated defocus amount, thereby performing focus adjustment of the imaging optical system 10.

[0030] The control unit 28 is configured with a processor and a ROM (Read Only Memory) such as a RAM (Random Access Memory) and a flash memory. When a flash memory is used, the stored programs can be rewritten as needed. The control unit 28 realizes each function by executing programs, including a phase difference detection program, stored in the built-in ROM.

[0031] The imaging device body 3 includes a first imaging element 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 an image processing unit 32 that processes an image signal obtained by capturing a subject light image using the first imaging element 31 to generate captured image data.

[0032] In Fig. 2, the condenser lens 23 is omitted from the illustration in order to simply illustrate the luminous flux of subject light. In Fig. 2, luminous flux 201 is a simplified representation of the luminous flux of subject light that is reflected by the reflecting surface 16a of the beam splitter 16 and enters the mirror 22. luminous flux 202 is a simplified representation of the luminous flux of subject light that is reflected by the mirror 22 and enters the second image sensor 27. Optical axis K2 is the optical axis of luminous flux 202 (a representative virtual light ray). For example, optical axis K2 is the axis of rotational symmetry of condenser lens 23 or condenser lens 26.

[0033] Light that branches off from the first optical path and travels to the second optical path first forms a real image at a certain position on the second optical path (first imaging position P1). The light that formed the real image then continues on the second optical path, but as shown in FIG. 2, it spreads further as it travels. This spread light is then collected by an optical system including a collecting lens 26 and again forms a real image on the second image sensor 27 (second imaging position P2). Because the light that forms an image on the second image sensor 27 comes from different directions, pupil division of each pixel of the second image sensor 27 using a light-shielding film can be performed so that only light from a specific direction can be detected.

[0034] The direction of the optical axis K2 (the horizontal direction in FIG. 2) is the Z direction, the direction of pupil division in the second image sensor 27 (the vertical direction in FIG. 2) is the Y direction, and the direction intersecting the Z direction and the Y direction (the depth direction in FIG. 2) is the X direction. Note that intersecting here includes being perpendicular.

[0035] The light-shielding portion 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 on the optical axis K2. Although FIG. 2 does not show the shading of the light beam 202 by the diaphragm 24 and the light-shielding portion 25, in reality, the light beam 202 is narrowed down by the diaphragm 24 and separated in the Y direction by the light-shielding portion 25 before entering the second image sensor 27.

[0036] <Light blocking portion 25 seen from the direction of optical axis K2> FIG. 3 is a diagram illustrating an example of the light-shielding portion 25 as viewed from the direction of the optical axis K2. In FIG. 3, a straight line 301 intersects the Y direction (pupil division direction) and the optical axis K2. The light-shielding portion 25 has a shape that is symmetrical about the straight line 301 as viewed from the direction of the optical axis K2. This allows the light beam 202 to be evenly divided in the Y direction. Note that the shape of the portion of the light-shielding portion 25 that does not block the light beam 202 does not need to be symmetrical about the straight line 301. Note that 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. It is most preferable that the straight line 301 of the light-shielding portion 25 be perpendicular to the Y direction and the optical axis K2, but it is not limited to intersecting at exactly 90°.

[0037] <Angle Sensitivity Characteristics of Phase Difference Detection Pixels in the Second Image Sensor 27> 4 is a graph showing an example of the angle sensitivity characteristic of a phase difference detection pixel in the second image sensor 27. An angle sensitivity characteristic 41 indicated by a dashed dotted line indicates the characteristic of light reception sensitivity with respect to the angle of incidence of one of a pair of light rays resulting from pupil division in the Y direction in the phase difference detection pixel of the second image sensor 27. As described above, the phase difference detection pixel in the second image sensor 27 performs pupil division using a light-shielding film formed in the pixel.

[0038] Angle sensitivity characteristic 42 indicated by a two-dot chain line indicates the characteristic of light reception sensitivity with respect to the angle at which the other of a pair of light rays resulting from pupil division in the Y direction is incident, at the phase difference detection pixel of the second image sensor 27. Angle sensitivity characteristic 40 indicates, for reference, the characteristic of light reception sensitivity with respect to the angle at which a light ray is incident, at the first image sensor 31.

[0039] As shown in angular sensitivity characteristics 41 and 42, the peaks of the angular sensitivity characteristics of a pair of light rays resulting from pupil division in the Y direction are shifted. By realizing such angular sensitivity characteristics 41 and 42 using a light-shielding film in the phase difference detection pixel of second image sensor 27, control unit 28 can derive the defocus amount by performing correlation calculation on the signal of the phase difference pixel having angular sensitivity characteristic 41 and the signal of the phase difference pixel having angular sensitivity characteristic 42.

[0040] Here, when the focus is significantly out of focus, it becomes difficult to calculate a reliable defocus amount from the results of the correlation calculation. In Figure 4, when the focus is significantly out of focus, the peak on the negative side of the incident angle in angle sensitivity characteristic 41 is relatively lower than the sensitivity near the incident angle of 0°, and the same is true for angle sensitivity characteristic 42. In such cases, the results of the correlation calculation become less reliable, and distance measurement accuracy in conventional configurations is reduced. In contrast, in imaging device 100, this reduction in distance measurement accuracy is suppressed by using light shielding portion 25 to block part of the subject light incident on second imaging element 27.

[0041] <Light beam angle range and luminous flux 202 at each F-number> 5 is a diagram showing an example of the ray angle range and light beam 202 in the case of F1.4. Light beam angle range 51 is the angular range of light beam 202 incident on second image sensor 27 when it is assumed that light blocking section 25 is not provided. When the F-number of the optical system through which light beam 202 incident on second image sensor 27 passes is F1.4, light beam angle range 51 is as shown in FIG. 5, for example.

[0042] The F-number of the optical system through which the light beam 202 incident on the second imaging element 27 passes is, for example, the maximum F-number among the F-number of the aperture 14 of the imaging optical system 10 and the F-number of the aperture 24 of the phase difference detection optical system 20.

[0043] The shaded light blocking range 52 is the angular range of light rays that are blocked by providing the light blocking portion 25, among the light beam 202 that enters the second image sensor 27. As shown in Fig. 3, the light blocking portion 25 extends in the X direction and has a symmetrical shape about a straight line 301 that intersects with the Y direction (pupil division direction) and the optical axis K2. Therefore, the light blocking range 52 is a central portion of the light ray angular range 51.

[0044] This makes it possible to block light rays at the center of light ray angle range 51, where the degree of overlap between angle sensitivity characteristics 41 and 42 is large. Therefore, even in a state where the focus is significantly out of focus, it is possible to reduce blurring of each of the pair of images obtained by second image sensor 27 and suppress deterioration of distance measurement accuracy.

[0045] 5, the case where the F-number 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 the following Figures 6 to 9, the control unit 28 may perform control to adjust the light blocking width (width in the Y direction) of the light blocking unit 25 based on this F-number. The configuration of the light blocking unit 25 that can adjust the light blocking width will be described later (see Figure 10, etc.).

[0046] Fig. 6 is a diagram showing an example of the light ray angle range and light beam 202 in the case of F2. As shown in Fig. 6, when the F-number of the optical system through which light beam 202 incident on second image sensor 27 passes is F2, the diameter of light beam 202 is smaller and light ray angle range 51 is also narrower than when the F-number is F1.4 (Fig. 5). In response to this, control unit 28 narrows light-blocking range 52 by performing control to narrow the width of light-blocking unit 25 in the Y direction compared to when the F-number is F1.4.

[0047] Fig. 7 is a diagram showing an example of the light ray angle range and light beam 202 in the case of F2.8. As shown in Fig. 7, when the F-number of the optical system through which light beam 202 incident on second image sensor 27 passes is F2.8, the diameter of light beam 202 is smaller and light ray angle range 51 is narrower than when the F-number is F2 (Fig. 6). In response to this, control unit 28 narrows light-blocking range 52 by performing control to narrow the width of light-blocking unit 25 in the Y direction compared to when the F-number is F2.

[0048] Fig. 8 is a diagram showing an example of the light ray angle range and light beam 202 in the case of F4. As shown in Fig. 8, when the F-number of the optical system through which light beam 202 incident on second image sensor 27 passes is F4, the diameter of light beam 202 is smaller and light ray angle range 51 is also narrower than when the F-number is F2.8 (Fig. 7). In response to this, control unit 28 narrows light-blocking range 52 by performing control to narrow the width of light-blocking unit 25 in the Y direction compared to when the F-number is F2.8.

[0049] Fig. 9 is a diagram showing an example of the ray angle range and ray beam 202 in the case of F8. As shown in Fig. 9, when the F-number of the optical system through which ray beam 202 incident on second image sensor 27 passes is F8, the diameter of ray beam 202 is smaller and ray angle range 51 is narrower than when the F-number is F4 (Fig. 8). In response to this, control unit 28 narrows ray-blocking range 52 by performing control to narrow the width of light-blocking unit 25 in the Y direction compared to when the F-number is F4.

[0050] If the F-number of the optical system through which the light beam 202 incident on the second imaging element 27 passes is large (for example, F11), the control unit 28 may set the Y-direction width of the shading portion 25 to 0, i.e., the shading portion 25 may not shade the light beam 202.

[0051] 5 to 9, control unit 28 may adjust the light-blocking width of light-blocking unit 25 in accordance with the opening size (F-number) of diaphragms 14, 24 included in the optical system through which subject light incident on second imaging element 27 passes. Specifically, control unit 28 adjusts the light-blocking width of light-blocking unit 25 so that the smaller the opening size of diaphragms 14, 24 (the larger the F-number), the narrower the light-blocking width of light-blocking unit 25 becomes.

[0052] This makes it possible to narrow the light blocking range 52 in accordance with the light ray angle range 51, which narrows as the aperture amounts of the diaphragms 14 and 24 become smaller. This makes it possible to prevent a situation in which the amount of subject light at the second image sensor 27 is insufficient, making it difficult to calculate the phase difference. Note that when the aperture amounts of the diaphragms 14 and 24 are small, the blurring of the pair of images obtained by the second image sensor 27 is small, and therefore narrowing the light blocking width of the light blocking portion 25 has little effect on distance measurement accuracy.

[0053] <Light-shielding portion 25 with variable light-shielding width> 10 is a diagram showing an example of a light-shielding unit 25 with a variable light-shielding width. For example, the light-shielding unit 25 is rotatable about a rotation axis 60 that is parallel to the Z direction. The light-shielding unit 25 also has a plurality of light-shielding plates 61 to 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.

[0054] The light blocking plates 61 to 65 have different widths (the lengths in the circumferential direction of a circle centered on the rotation axis 60). Specifically, the light blocking plate 61 has the widest width, followed by the light blocking plate 62, the light blocking plate 63, the light blocking plate 64, and the light blocking plate 65 in that order.

[0055] Further, the light blocking unit 25 has an annular outer peripheral portion 66 centered on the rotation axis 60, and the light blocking plates 61 to 65 are fixed to the inside of the outer peripheral portion 66. The light blocking unit 25 is disposed so that the optical axis K2 passes between the rotation axis 60 and the outer peripheral portion 66.

[0056] The rotation of the light blocking portion 25 is performed, for example, by controlling a drive mechanism (e.g., a motor such as a stepping motor) not shown by the control portion 28. The control portion 28 controls the rotation angle of the light blocking portion 25 in accordance with the F-number of the optical system through which the light beam 202 incident on the second image sensor 27 passes.

[0057] For example, when the F-number is F1.4 (see FIG. 5), the control unit 28 controls the rotation angle of the light blocking unit 25 so that the center of the light blocking plate 61 coincides with the optical axis K2, as shown in FIG. 10. When the F-number is F2 (see FIG. 6), the control unit 28 controls the rotation angle of the light blocking unit 25 so that the center of the light blocking plate 62 coincides with the optical axis K2.

[0058] Furthermore, when the F-number is F2.8 (see FIG. 7), the control unit 28 controls the rotation angle of the light blocking unit 25 so that the center of the light blocking plate 63 coincides with the optical axis K2. Furthermore, when the F-number is F4 (see FIG. 8), the control unit 28 controls the rotation angle of the light blocking unit 25 so that the center of the light blocking plate 64 coincides with the optical axis K2. Furthermore, when the F-number is F8 (see FIG. 9), the control unit 28 controls the rotation angle of the light blocking unit 25 so that the center of the light blocking plate 65 coincides with the optical axis K2.

[0059] Furthermore, when the F-number is greater than F8 (for example, F11), the control unit 28 may control the rotation angle of the light blocking unit 25 so that the light beam 202 centered on the optical axis K2 is not blocked by any of the light blocking plates 61 to 65.

[0060] 10, the width of the portion of light-shielding portion 25 that blocks light beam 202 can be controlled by rotating light-shielding portion 25. However, light-shielding portion 25 with a variable light-shielding width is not limited to the example shown in Fig. 10, and may be configured, for example, by a non-transmitting region of a liquid crystal panel whose transmitting region can be changed by an applied voltage. Also, diaphragm 24 can be configured by a liquid crystal panel, and in this case, diaphragm 24 and light-shielding portion 25 may be configured by a single liquid crystal panel.

[0061] As described above, the imaging device 100 includes a beam splitter 16 (branching unit) that branches the optical path of the subject light that has passed through the imaging optical system 10 into a first optical path that proceeds to the first imaging element 31 and a second optical path other than the first optical path, a second imaging element 27 that has phase difference detection pixels that pupil-divide and receive the subject light that proceeds along the second optical path, and a light-shielding unit 25 that includes the optical axis K2 of the second optical path and extends in the X direction that intersects the Y direction of the pupil division and intersects the optical axis K2 of the second optical path.

[0062] This blocks the portion of the subject light incident on the second image sensor 27 that passes through the optical axis K2 and extends in the X direction, thereby reducing image blur when the image is significantly out of focus. Therefore, even when the image is significantly out of focus, the phase difference can be correctly calculated based on the pair of image signals output from the second image sensor 27, and a decrease in distance measurement accuracy can be suppressed.

[0063] Furthermore, the imaging device 100 includes condenser lenses 21, 23, and 26 (optical system) that focus the subject light at a position between the beam splitter 16 (branching section) and the second imaging element 27 and focus the subject light again at the second imaging element 27, and the light-shielding section 25 is provided between the position where the subject light is focused between the beam splitter 16 (branching section) and the second imaging element 27 and the second imaging element 27. In other words, the light-shielding section 25 is provided at the same position on the second optical path as the position where the diaphragm 24 is suitable for being provided.

[0064] As a result, for example, even if the beam splitter 16 is not provided at the position of the diaphragm 14, it is possible to create a position in the phase difference detection optical system 20 through which all light rays pass, and to provide the light blocking portion 25 at that position. This improves the degree of freedom in designing the imaging optical system 10.

[0065] Furthermore, by making the light-blocking width of the light-blocking portion 25 adjustable, it is possible to block a portion of the subject light entering the second imaging element 27 in accordance with the diameter of the subject light. For example, the control unit 28 adjusts the light-blocking width of the light-blocking portion 25 in accordance with the opening size (F-number) of the diaphragm (apertures 14, 24) included in the optical system through which the subject light entering the second imaging element 27 passes. Specifically, the control unit 28 adjusts the light-blocking width of the light-blocking portion 25 so that the smaller the opening size of the diaphragm (the larger the F-number), the narrower the light-blocking width of the light-blocking portion 25. This makes it possible to prevent the amount of subject light at the second imaging element 27 from being insufficient, making distance measurement difficult.

[0066] <Variation 1> Depending on the type of lens, the control unit 28 may adjust the light-blocking width of the light-blocking unit 25 based on the focal length of the imaging optical system 10. Specifically, in the case of a lens whose maximum f-number changes depending on the zoom magnification, the control unit 28 adjusts the light-blocking width of the light-blocking unit 25 based on drive information for the zoom lens 12 so that the longer the focal length of the imaging optical system 10, the narrower the light-blocking width. This makes it possible to prevent the second imaging element 27 from experiencing an insufficient amount of subject light, which can make distance measurement difficult.

[0067] Furthermore, the control unit 28 may adjust the light-blocking width of the light-blocking unit 25 based on both the aperture size of the diaphragm and the focal length of the imaging optical system 10. For example, a memory included in the imaging device 100 stores correspondence information indicating the light-blocking width of the light-blocking unit 25 for each combination of the aperture size and the focal length of the imaging optical system 10, and the control unit 28 adjusts the light-blocking width of the light-blocking unit 25 using this correspondence information.

[0068] <Variation 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 body 3. For example, in the configuration shown in Fig. 1, the beam splitter 16, the phase difference detection optical system 20, and the second imaging element 27 may be provided in the imaging device body 3. In this case, the beam splitter 16 is provided closer to the subject than the first imaging element 31.

[0069] Furthermore, the control unit 28 may be configured to be provided in the imaging device body 3. When the control unit 28 is provided in the imaging device body 3 and the lens device 1 is an interchangeable type, the control unit 28 may acquire information on the focal length of the lens device 1 attached to the imaging device body 3 from the lens device 1, and adjust the light-blocking width of the light-blocking unit 25 based on the focal length of the imaging optical system 10.

[0070] As described above, the present specification discloses the following:

[0071] (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 that proceeds to the first imaging element and a second optical path other than the first optical path; a second image sensor having a phase difference detection pixel that receives the subject light traveling through the second optical path by pupil division; a light-blocking portion that includes an optical axis of the second optical path, and extends in a direction that intersects with the pupil division direction and the optical axis of the second optical path; A phase difference detection device comprising:

[0072] (2) The phase difference detection device according to (1), the second optical path includes an optical system that forms an image of the subject light at a position between the branching section and the second image sensor and forms an image of the subject light again at the second image sensor; the light-shielding portion is located between the position and the second imaging element; Phase difference detection device.

[0073] (3) The phase difference detection device according to (2), the light blocking portion is located at a position overlapping with an aperture provided at the position for adjusting the amount of subject light incident on the second image sensor, on the optical axis of the second optical path; Phase difference detection device.

[0074] (4) A phase difference detection device according to any one of (1) to (3), The width of the light blocking portion in the pupil division direction is adjustable. Phase difference detection device.

[0075] (5) The phase difference detection device according to (4), the width is adjusted based on the opening size of a diaphragm that adjusts the amount of subject light incident on the second imaging element. Phase difference detection device.

[0076] (6) The phase difference detection device according to (5), The width is adjusted to be narrower as the opening amount is smaller. Phase difference detection device.

[0077] (7) A 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 optics. Phase difference detection device.

[0078] (8) The phase difference detection device according to (7), The width is adjusted to be narrower as the focal length is longer. Phase difference detection device.

[0079] (9) A phase difference detection device according to any one of (1) to (8), the light-shielding portion of the light-shielding unit has a shape symmetrical about a line that includes the optical axis, the direction of the pupil division, and intersects with the optical axis; Phase difference detection device.

[0080] (10) A phase difference detection device according to any one of (1) to (9), the imaging optical system; A lens device comprising:

[0081] (11) A phase difference detection device according to any one of (1) to (9), the first imaging element; An imaging device comprising:

[0082] (12) A phase difference detection device according to any one of (1) to (9), wherein the imaging optical system includes a focus lens; a first image sensor 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:

[0083] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0084] This application is based on a Japanese patent application (Patent Application No. 2021-014008) filed on January 29, 2021, the contents of which are incorporated by reference into this application. [Industrial Applicability]

[0085] 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 object is significantly out of focus. [Explanation of symbols]

[0086] 1 Lens device 3. Imaging device body 10 Imaging optical system 11 Focus Lens 12 Zoom Lens 14,24 aperture 15 Master lens group 16 Beam Splitter 16a Reflective surface 17 Image stabilization lens 20 Phase difference detection optical system 21, 23, 26 Condenser lens 22 Mirror 25 Light blocking section 27 Second image sensor 28 Control Unit 29 Drive mechanism 31 First image sensor 32 Image processing section 40~42 Angle sensitivity characteristics 51 beam angle range 52 Shading range 60 Rotational Axis 61~65 Shade 66 Outer periphery 100 Imaging device 201,202 luminous flux 301 straight line K1, K2 optical axis P1 First imaging position P2 Second imaging position

Claims

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 that proceeds to the first imaging element and a second optical path other than the first optical path; a second image sensor having a phase difference detection pixel that receives the subject light traveling through the second optical path by pupil division; a light-blocking portion that includes an optical axis of the second optical path, and extends in a direction that intersects with the pupil division direction and the optical axis of the second optical path; Equipped with The width of the light blocking portion in the pupil division direction is adjustable. Phase difference detection device.

2. 2. 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 image sensor and forms an image of the subject light again at the second image sensor, the light-shielding portion is located between the position and the second imaging element. Phase difference detection device.

3. 3. The phase difference detection device according to claim 2, the light blocking portion adjusts the amount of subject light incident on the second image sensor and is located at a position overlapping with an aperture provided at the position on the optical axis of the second optical path. Phase difference detection device.

4. A phase difference detection device according to any one of claims 1 to 3, the width is adjusted based on the opening amount of a diaphragm that adjusts the amount of subject light incident on the second image sensor; Phase difference detection device.

5. A phase difference detection device according to claim 4, The width is adjusted to be narrower as the opening amount is smaller. Phase difference detection device.

6. A phase difference detection device according to any one of claims 1 to 5, the imaging optical system has a variable focal length; The width is adjusted based on the focal length of the imaging optics. Phase difference detection device.

7. A phase difference detection device according to claim 6, The width is adjusted to be narrower as the focal length is longer. Phase difference detection device.

8. A phase difference detection device according to any one of claims 1 to 7, the light-shielding portion of the light-shielding unit has a shape that is symmetrical about a line that includes the optical axis, the direction of the pupil division, and intersects with the optical axis; Phase difference detection device.

9. A phase difference detection device according to any one of claims 1 to 8; the imaging optical system; A lens device comprising:

10. A phase difference detection device according to any one of claims 1 to 8; the first imaging element; An imaging device comprising:

11. A phase difference detection device according to any one of claims 1 to 8, wherein the imaging optical system is equipped with a focus lens; a first image sensor 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:

Images