JP4569268B2 - Focus detection module and camera - Google Patents

Description

  The present invention relates to a focus detection module in which a light beam from a focus detection region set off-axis is deflected and guided to an image sensor for focus detection.

  A focus detection module disclosed in Japanese Patent Laid-Open No. 2000-82279 (Patent Document 1) is known. In this focus detection module, the focus detection light beam emitted from the re-imaging lens unit is made incident on the peripheral region of the re-imaging lens unit, that is, the peripheral region on the optical axis side of the focus detection optical system. It is made to be substantially parallel to the optical axis of the focus detection optical system. With this focus detection module, even if the image sensor chip is attached to the optical axis of the focus detection optical system so as to be tilted around an axis perpendicular to the pupil division direction, the focus detection result is obtained without adding an optical element. Error is not included. As a result, the angle adjustment mechanism of the image sensor chip is not required, and the increase in size and cost of the focus detection module can be suppressed to a minimum.

  Further, a focus detection module disclosed in Japanese Patent Laid-Open No. 5-142465 (Patent Document 2) is known. In this focus detection module, two off-axis focus detection areas are provided in order from the center of the imaging screen in the same radial direction. The photographing light flux is incident on each pair of photoelectric conversion elements corresponding to the two off-axis focus detection regions by the common condenser lens, the pupil division aperture, and the re-imaging lens.

Japanese Patent Laid-Open No. 2002-82279 JP-A-5-142465

However, when the focus detection optical system of Patent Document 1 is used for the focus detection module of Patent Document 2 in which the condenser lens, the pupil division mask, and the re-imaging lens are shared by the two focus detection regions, It is impossible to design the focus detection region so that the photographing light beam is perpendicularly incident on the photoelectric conversion element.
In view of the above, an object of the present invention is to make the size and cost of a focus detection module appropriate when any one focus detection region is configured so that a photographic light beam is vertically incident on a photoelectric conversion element.

(1) A first aspect of the present invention is a field mask having a plurality of apertures provided corresponding to a plurality of focus detection areas set in a photographic screen on the primary image plane of the photographic optical system, and an aperture of the field mask Focus detection optical system including a condenser lens that collects the light beam that has passed through the condenser lens, a pupil division mask that divides the light beam that has passed through the condenser lens, and a re-imaging lens that re-images each of the pair of pupil-divided light beams And a light receiving element that receives a pair of light beams re-imaged by the re-imaging lens. The plurality of focus detection areas are adjacent to the first off-axis area disposed outside the optical axis of the imaging optical system and on the side farther from the optical axis than the first off-axis area along the radial direction from the optical axis. A plurality of light beams that pass through the apertures of the field mask corresponding to the first and second off-axis regions, respectively, and are re-imaged by a pair of pupil division masks and a re-imaging lens. Among the plurality of re-imaged light beams, the light beam that passes through the first off-axis region and is re-imaged by the re-imaging lens is incident substantially perpendicular to the light receiving surface of the light receiving element in the radiation direction. The focus detection optical system is configured as described above.
(2) According to the invention of claim 2, in the focus detection module of claim 1, the optical axis of the re-imaging lens is substantially parallel to the optical axis of the focus detection optical system, and the position of the center of gravity of the opening of the pupil division mask Is located closer to the optical axis of the focus detection optical system than the optical axis of the re-imaging lens.
(3) According to a third aspect of the present invention, in the focus detection module of the second aspect, the optical axis of the re-imaging lens is such that the light beam emitted from the re-imaging lens is substantially parallel to the optical axis of the focus detection optical system. Is tilted at a predetermined angle with respect to the optical axis of the focus detection optical system.
(4) A fourth aspect of the present invention is the focus detection module according to any one of the first to third aspects, wherein the third off-axis is further provided on the opposite side of the second off- axis region to the first off-axis region. When the region is provided, and when the third and fourth off-axis regions are further provided on the side opposite to the first off-axis region with respect to the second off-axis region, the second off-axis region is The focus detection optical system is configured so that the transmitted light beam is incident on the light receiving element substantially perpendicularly.
(5) A camera according to a fifth aspect includes the focus detection module according to any one of the first to fourth aspects.

  According to the present invention, in the focus detection module having two focus detection areas set outside the optical axis of the photographing screen, the focus detection light beam in the first off-axis area close to the optical axis is incident on the light receiving element substantially perpendicularly. did. Therefore, compared with the case where the optical system is designed so that the focus detection light beam in the second off-axis focus detection region arranged at a position far from the optical axis is incident on the light receiving element substantially perpendicularly, the thickness of the shared condenser lens is reduced. As a result, an increase in size of the focus detection module can be suppressed.

  The first and second embodiments of the present invention will be described with reference to FIGS. Each embodiment is common except that the condenser lens and the re-imaging lens are different.

-First embodiment-
FIG. 1 is a schematic configuration diagram of a single-lens reflex camera equipped with a focus detection module according to the present invention. The light beam from the subject is guided through the photographing lens LE in the lens barrel LB and guided into the camera body CB. A part of the light beam guided to the camera body CB passes through the semi-transmissive main mirror 51, is reflected downward by the sub mirror 52, and then enters the focus detection module 100. The CPU 56 drives the lens drive motor 57 based on the focus detection signal that is the output of the focus detection module 100 to adjust the focus of the photographic lens LE. On the other hand, the light beam reflected by the main mirror 51 is observed by the eyepiece lens 55 via the pentaprism 54.

  In the present embodiment, focus detection is performed for the five focus detection areas shown in FIG. That is, a region C extending in the ± X direction around the optical axis LX of the photographing screen and an off-axis focus detection region AR, BR, AL, BL in the X axis direction passing through the optical axis LX. The area AR is an area that is separated from the optical axis LX in the + X direction (rightward) and extends in the Y direction. The region AL is a region that is separated from the optical axis LX in the −X direction (leftward) and extends in the Y direction. The region BR set adjacent to the region AR is a region on the X axis that is more off-axis than the region AR, and is a region that is separated from the optical axis LX in the + X direction (rightward) and extends in the Y direction. is there. The region BL set adjacent to the region BR is a region on the X axis that is off-axis from the region AL, and is a region that is separated from the optical axis LX in the −X direction (leftward) and extends in the Y direction. It is. Here, the off-axis focus detection areas AR and BR are arranged in order on a line in the X-axis direction passing through the optical axis. The same applies to the off-axis focus detection areas AL and BL.

  The focus detection module 100 performs focus detection by a well-known phase difference detection method. As shown in FIG. 3, the optical system has a field mask 122, a condenser lens 124, a diaphragm mask (pupil division mask) 128, The imaging lens 129 and the image sensor chip 130 are provided.

  The field mask 122 has an opening 122C corresponding to the focus detection area C on the optical axis and openings 122AR, 122AL, 122BR, 122BL corresponding to the off-axis focus detection areas AR, AL, BR, and BL, respectively. The condenser lens 124 has lens portions 124C, 124L, and 124R corresponding to the openings of the field mask 122. The lens portion 124 </ b> C of the condenser lens 124 guides the light beam incident from the opening 122 </ b> C of the field mask 122 to the aperture mask 128. The lens portion 124 </ b> L of the condenser lens 124 guides the light beam incident from the openings 122 </ b> AL and 122 </ b> BL of the field mask 122 to the aperture mask 128. The lens portion 124 </ b> R of the condenser lens 124 guides the light beam incident from the openings 122 </ b> AR and 122 </ b> BR of the field mask 122 to the aperture mask 128. That is, the off-axis focus detection areas AR and BR share the condenser lens 124R, and the off-axis focus detection areas AL and BL share the condenser lens 124L.

  The aperture mask 128 has openings 128CR, 128CL, 128RU, 128RD, 128LU, and 128LD corresponding to five focus detection areas, respectively. That is, the focus detection light beam that passes through the focus detection region C is split into pupils at the pair of openings 128CR and 128CL, and the focus detection light beam that passes through the focus detection regions AR and BR is split into pupils at the pair of openings 128RU and 128RD, A focus detection light beam that passes through the focus detection areas AL and BL is divided into pupils by a pair of openings 128LU and 128LD. Therefore, the focus detection areas AR and BR share a pair of openings 128RU and 128RD, and the focus detection areas AL and BL share a pair of openings 128LU and 128LD.

  The re-imaging lens 129 includes lens portions (hereinafter simply referred to as re-imaging lenses) 129CR, 129CL, 129RU, 129RD, 129LU, and 129LD corresponding to five focus detection areas. Similarly, the image sensor chip 130 holds image sensor arrays (light receiving elements) 130CR, 130CL, 130ARU, 130ARD, 130BRU, 130BRD, 130ALU, 130ALD, 130BLU, and 130BLD corresponding to five focus detection areas on the same surface. .

  That is, the pair of focus detection light beams that have passed through the focus detection region C and are pupil-divided by the pair of openings 128CR and 128CL are imaged on the image sensor arrays 130CR and 130CL by the re-imaging lenses 129CR and 129CL, respectively. . The focus detection light beams that pass through the focus detection areas AR and BR and are pupil-divided by the pair of openings 128RU and 128RD are re-imaging lenses 129RU and 129RD, respectively, and image sensor arrays 130ARU and 130ARD, and image sensor array 130BRU. The image is formed on 130BRD. Further, the focus detection light beams that pass through the focus detection areas AL and BL and are divided into pupils by the pair of openings 128LU and 128LD are image sensor arrays 130ALU and 130ALD and image sensor arrays by re-imaging lenses 129LU and 129LD, respectively. Images are formed on 130 BLU and 130 BLD. Therefore, the focus detection areas AR and BR share a pair of aperture mask openings 128RU and 128RD and a pair of re-imaging lenses 129RU and 129RD, and the focus detection areas AL and BL have a pair of aperture mask openings 128LU and 128LD. The pair of re-imaging lenses 129LU and 129LD are shared. In addition, FIG. 4 shows each optical system element corresponding to the focus detection areas C, AR, BR, AL, and BL in a list form.

  As described above, the focus detection optical system of this embodiment corresponds to the plurality of focus detection areas C, AR, AL, BR, and BL set in the shooting screen on the primary image plane of the shooting optical system. A field mask 122 having a plurality of openings 122C, 122AR, 122AL, 122BR, and 122BL, a condenser lens 124 that collects the light beam that has passed through the opening of the field mask 122, and a light beam that has passed through the condenser lens 124 as a pupil. An aperture mask (pupil division mask) 128 to be divided and a re-imaging lens 129 that re-images a pair of pupil-divided light beams.

  The first embodiment will be described in more detail based on FIG. 5 (a) and FIG. FIG. 5 is a diagram for explaining the light beams incident on the off-axis focus detection areas AL and BL of the focus detection module 100 in the XZ plane. In order to simplify the explanation, FIGS. 5A and 6 show the focus detection optical systems related to the focus detection areas AL and BL, particularly the aperture mask apertures 128LU and 128LD, the re-imaging lens 129LU, and the image sensor 130ALU. The 130BLU will be described.

  In FIG. 5A, the apertures 128LU and 128LD of the aperture mask 128, the re-imaging lenses 129LU and 129LD, the image sensor arrays 130ALU and 130ALD, the pair of light beams ALU and ALD, and the pair of light beams BLU and BLD, respectively, It overlaps in the orthogonal direction. The pair of light beams ALU and ALD are light beams that pass through the pair of openings 128LU and 128LD of the aperture mask 128 through the off-axis focus detection area AL. The pair of light beams BLU and BLD are light beams that pass through the pair of apertures 128LU and 128LD of the aperture mask 128 through the off-axis focus detection region BL.

  The focus detection light beam in the off-axis focus detection area AL set by the opening 122AL of the field mask 122 is divided through the lens portion 124L located outside the optical axis O2 of the focus detection optical system in the condenser lens 124. The light beams ALU and ALD (strictly, the light beams that project the apertures 128LU and 128LD onto the photographing lens side) are deflected toward the optical axis O2 and enter the re-imaging lenses 129LU and 129LD. Similarly, the focus detection light beam in the off-axis focus detection region BL set by the opening 122BL of the field mask 122 is further peripheral to the lens portion 124L located outside the optical axis O2 of the focus detection optical system in the condenser lens 124. Since the divided light beams BLU and BLD pass through the region (strictly, the light beams projecting the apertures 128LU and 128LD onto the photographing lens side) are deflected toward the optical axis O2 and enter the re-imaging lenses 129LU and 129LD. FIG. 5 shows the element with the subscript L, the optical path, that is, the focus detection areas AL and BL. In the following description, for the sake of convenience, the element with the subscript L, the optical path, that is, the focus detection areas AL and BL will be described.

  Thus, the condenser lens 124 deflects the light beams ALU and ALD and the light beams BLU and BLD from the off-axis focus detection areas AL and BL toward the optical axis O2, so that the off-axis focus detection areas AL and BL are aligned with the optical axis. The image sensor array 130ALU, 130BLU, and 130ALD, 130BLD can be arranged close to the optical axis O2 even when they are relatively far from O2, and the image sensor chip 130 can be downsized. However, as described above, when the light beams ALU and ALD are obliquely incident on the sensor arrays 130ALU and 130ALD, or when the light beams BLU and BLD are obliquely incident on the sensor arrays 130BLU and 130BLD, as described in the related art, Is attached to the light beam in a rotational direction centered on the X axis in FIG. 5, a focus detection error occurs. Therefore, in the first embodiment, the occurrence of a focus detection error is prevented as follows.

  As shown in detail in FIG. 6, the re-imaging lens 129LU has an entrance-side spherical surface 5f and an exit-side spherical surface 6f having the same curvature. A line segment connecting the center 7f of the entrance-side spherical surface 5f and the center 8f of the exit-side spherical surface 6f becomes the optical axis 11f of the re-imaging lens 129LU. In this embodiment, the light flux ALU divided by the aperture mask aperture 128LU is incident on the peripheral region near the focus detection optical system optical axis O2 in the peripheral region of the re-imaging lens 129LU. That is, the gravity center position 17f of the aperture 128LU of the aperture mask 128 is positioned closer to the focus detection optical system optical axis O2 than the optical axis 11f of the re-imaging lens 129LU, and the luminous flux ALU obliquely incident on the re-imaging lens 129LU is obtained. The light is emitted substantially parallel to the optical axis O2 of the focus detection optical system. According to this configuration, the focus detection light beams ALU and ALD in the off-axis focus detection area AL are bent by the re-imaging lenses 129LU and 129LD, respectively, and enter the image sensors 130ALU and 130ALD almost perpendicularly. Further, the focus detection light beams BLU and BLD in the off-axis focus detection region BL are bent by the re-imaging lenses 129LU and 129LD, respectively, but obliquely enter the image sensor 130BLU and the image sensor BLD.

  In such a focus detection module of the first embodiment, the off-axis re-imaging lens 129LU (129LD) includes the incident-side spherical surface 5f and the exit-side spherical surface 6f having the same curvature, and the center of the incident-side spherical surface 5f. When the line segment 11f connecting 7f and the center 8f of the exit-side spherical surface 6f is the optical axis of the off-axis re-imaging lens 129LU (129LD), the optical axis 11f of the off-axis re-imaging lens 129LU (129LD) is the pupil. The projection when projected onto the XZ plane perpendicular to the dividing direction is substantially parallel to the optical axis O2 of the focus detection optical system, and the center of gravity position 17f of the pair of apertures 128LU (128LD) is the off-axis re-imaging lens 129LU. It is located closer to the optical axis O2 side of the focus detection optical system than the optical axis 11f of (129LD).

  As a result, according to the focus detection module of the first embodiment, the apertures 128LU and 128LD of the aperture mask 128 are arranged in the peripheral region near the focus detection optical system optical axis O2 among the peripheral regions of the re-imaging lenses 129LU and 129LD. The luminous fluxes ALU and ALD divided by (1) enter. Therefore, the light beams incident on the re-imaging lenses 129LU and 129LD are refracted to the optical axis 11f side, and the light beams ALU and ALD emitted from the re-imaging lenses 129LU and 129LD are the optical axes of the focus detection optical system. It travels substantially parallel to O2 and enters the image sensor arrays 130ALU and 130ALD. As a result, even if the image sensor chip 130 is mounted tilted around the X axis, the subject images formed on the image sensor arrays 130ALU and 130ALD do not shift in the X direction, and the focus detection accuracy does not deteriorate. .

  Then, in determining which of the off-axis focus detection areas AR and AL near the optical axis and off-axis focus detection areas BR and BL far from the optical axis are to be perpendicularly incident on the image sensor array, The focus detection light beams in the off-axis focus detection areas AR and AL close to the axis are vertically incident on the image sensor array. If the focus detection light beams in the off-axis focus detection regions BR and BL far from the optical axis are to be vertically incident on the image sensor array, the thickness of the common condenser lens in the axial direction is increased, and the focus detection module is increased in size. The reason will be described with reference to FIG.

  As can be understood from FIG. 5B, the off-axis focus detection area BL is farther from the optical axis than the off-axis focus detection area AL. Therefore, in order to make the focus detection light beam BLU passing through the off-axis focus detection region BL of the field mask 122 enter the peripheral region closer to the optical axis O2 of the re-imaging lens 129LU, it is compared with FIG. Therefore, the light beam BLU needs to be incident on the outer peripheral region of the condenser lens 124. This region is a region where the condenser lens 124 is very thin, and the condenser lens 124 must be thickened as a whole. However, if the thickness of the condenser lens 124 is increased, the focus detection module becomes larger. Therefore, if the focus detection light beams in the focus detection areas AR and AL close to the optical axis are made to enter the image sensor array perpendicularly, it is not necessary to increase the thickness of the condenser lens 122, and the enlargement of the focus detection module is suppressed. be able to.

  Also, the main subject is often near the optical axis in the shooting screen, and the focus detection areas AR and AL close to the focus detection optical axis have an influence on the focus detection accuracy due to the tilt of the image sensor array as described above. It is preferable to reduce it.

-Second embodiment-
FIG. 7A and FIG. 8 are diagrams illustrating the focus detection module of the second embodiment. The difference from the first embodiment is that the re-imaging lenses 129RU, RD, LU, and LD are tilted. In order to simplify the description, FIGS. 7A and 8 describe the focus detection optical system related to the focus detection areas AL and BL, particularly the re-imaging lens 129LU and the image sensors 130ALU and 130BLU.

  In FIG. 7A, the optical axis of the re-imaging lens 129LU is tilted toward the optical axis O2 in the traveling direction of the focus detection light beam. As shown in FIG. 8, the optical axis 11f of the re-imaging lens 129LU is tilted in a plane (in the XZ plane) perpendicular to the pupil division direction (Y direction) with respect to the optical axis O2 of the focus detection optical system. ing. In other words, the projection obtained by projecting the optical axis 11f of the re-imaging lens 129LU onto the XZ plane perpendicular to the pupil division direction is tilted at a predetermined angle with respect to the focus detection optical system optical axis O2. Further, the center of gravity 17f of the aperture mask aperture 128LU is decentered closer to the optical axis O2 with respect to the lens center through which the optical axis 11f of the re-imaging lens 129LU passes.

  In the thus configured focus detection optical system, the focus detection light beams ALU and ALD deflected in the direction of the optical axis O2 by the condenser lens unit 124L are incident on a peripheral region near the optical axis O2 of the re-imaging lens 129LU. Therefore, the light beam incident on the re-imaging lens 129LU is refracted toward the optical axis 11f, and the light beam ALU emitted from the re-imaging lens 129LU is substantially parallel to the optical axis O2 of the focus detection optical system. It proceeds and enters the image sensor array 130ALU. As a result, even if the image sensor chip 130 is tilted about the X axis, the subject image formed on the image sensor array 130ALU is not shifted in the X direction, and the focus detection accuracy is not deteriorated. The tilt angle of the re-imaging lens 129LU is determined so that the light emitted from the re-imaging lens 129LU is parallel to the optical axis O2, and the position of the center of gravity 17 of the aperture 128LU with respect to the re-imaging lens 129LU is also determined. It is determined.

  Similar to the module of the first embodiment, the focus detection module of the second embodiment can provide the following effects. That is, the focus detection light beams in the off-axis focus detection areas AL and AR close to the optical axis O2 of the focus detection optical system are vertically incident on the image sensor arrays 130LU and LD, for the reason described above (FIG. 7B). Reference) The focus detection accuracy of the focus detection module in which two off-axis focus detection areas are set can be improved as a whole while suppressing the increase in size of the focus detection module.

  Although not shown, the re-imaging lenses 129RU and 129RD and the diaphragm mask 128 in the off-axis focus detection areas AR and BR arranged symmetrically with the off-axis focus detection areas AL and BL and the optical axis O2 interposed therebetween. The physical shapes and positional relationships of the apertures 128RU and 128RD in the off-axis focus detection areas AL and BL in the re-imaging lenses 129LU and 129LD and the apertures 128LU and 128LD of the aperture mask 128 are exactly the same.

  The focus detection modules according to the first and second embodiments of the present invention focus the focus detection light beam that passes through at least two focus detection areas set off-axis among the image light flux incident from the shooting lens by the condenser lens. In a focus detection module in which the image sensor chip is made compact by deflecting to the optical axis side of the detection optical system, the focus detection light beam obliquely incident on the re-imaging lens unit is incident on the focus detection optical system light in the focus detection area close to the optical axis. Injected substantially parallel to the axis. However, the present invention is not limited to the above embodiment, and includes all optical systems that realize similar functions.

  The focus detection module having two focus detection areas arranged in parallel off-axis has been described above. However, the focus detection module has three or more focus detection areas arranged in parallel off-axis, and condenser lenses are used for these focus detection light beams. The present invention can also be applied to a focus detection module that shares an aperture mask aperture for pupil division and a re-imaging lens. For example, in a focus detection module having three focus detection areas arranged side by side off-axis, a focus detection light beam that passes through the center focus detection area, that is, the second focus detection area from the optical axis, enters the image sensor vertically. The shape, arrangement, performance, etc. of the condenser lens, pupil division mask, and re-imaging lens are determined so that By adopting such an arrangement, the adjustment error due to the tilt of the image sensor chip is distributed almost evenly in the other two off-axis focus detection areas, and the focus detection area closest to the optical axis, or the most from the optical axis. The focus detection accuracy for the remote focus detection region can be ensured, and the focus detection accuracy of the focus detection module as a whole can be optimized.

  Further, in the focus detection module having four focus detection regions arranged in parallel off-axis, the focus detection light beam passing through the focus detection region disposed second from the optical axis is vertically incident on the image sensor. The shape, arrangement, and performance of the condenser lens, pupil division mask, and re-imaging lens are determined. By adopting such an arrangement, (1) the adjustment error due to the inclination of the image sensor chip is distributed almost evenly in the other three off-axis focus detection areas, and the focus detection accuracy for these focus detection areas is improved. It is possible to achieve a design that balances the optimization of the focus detection accuracy of the focus detection module as a whole and (2) giving priority to the accuracy of the off-axis focus detection region close to the optical axis.

  Further, an image sensor that uses a re-imaging lens as shown in FIGS. 5 and 6 of JP-A-2002-82279 to make the off-axis focus detection light beam substantially parallel to the optical axis of the focus detection optical system. The structure of the focus detection optical system for causing the light to enter the array perpendicularly is not limited to the embodiment described above.

Schematic showing the configuration of a camera equipped with a focus detection device The figure explaining the focus detection area in a photography screen The disassembled perspective view which shows the structure of the principal part of the focus detection module in one embodiment of this invention. The figure explaining the optical system element corresponding to a focus detection area (A) is a figure explaining the light beam which injects into the off-axis focus detection areas AL and BL of the focus detection module 100 by 1st Embodiment, (b) is a figure which shows a comparative example. The figure which expands and shows a part of focus detection module of FIG. (A) is a figure explaining the light beam which injects into the off-axis focus detection areas AL and BL of the focus detection module 100 by 1st Embodiment, (b) is a figure which shows a comparative example. The figure which expands and shows a part of focus detection module of FIG.

Explanation of symbols

100: focus detection module 122: field mask 124: condenser lenses 124C, 124R, 124L: lens portion 128: aperture mask 128CR, CL, ARU, ARD, BRU, BLU, ALU, ALD, BLU, BLD: apertures 124, 124CR, CL, ARU, ARD, BRU, BLU, ALU, ALD, BLU, BLD: Re-imaging lens 130: Image sensor chip 130CR, CL, ARU, ARD, BRU, BLU, ALU, ALD, BLU, BLD: Image sensor array CB: Camera body C, AR, BR, AL, BL: Focus detection area LB: Shooting lens barrel LE: Shooting lens O2: Optical axis of focus detection optical system

Claims (5)

A field mask having a plurality of apertures provided corresponding to a plurality of focus detection areas set in the imaging screen on the primary image plane of the imaging optical system;
A condenser lens that condenses the light beam that has passed through the opening of the field mask;
A focus detection optical system including a pupil division mask for pupil-dividing the light beam transmitted through the condenser lens, and a re-imaging lens for re-imaging each of the pair of pupil-divided light beams;
In a focus detection module having a light receiving element that receives the pair of light beams re-imaged by the re-imaging lens,
The plurality of focus detection areas include a first off-axis area disposed outside the optical axis of the photographing optical system, and a side farther from the optical axis than the first off-axis area along a radial direction from the optical axis. A second off-axis region adjacent to
A plurality of light beams that pass through the opening of the field mask corresponding to each of the first and second off-axis regions are re-imaged by a pair of pupil division masks and a re-imaging lens, and re-imaged. Of the luminous flux, the focal point is such that a luminous flux that passes through the first off-axis region and is re-imaged by the re-imaging lens is incident substantially perpendicular to the light-receiving surface of the light-receiving element in the radiation direction. A focus detection module comprising a detection optical system. The focus detection module of claim 1.
The optical axis of the re-imaging lens is substantially parallel to the optical axis of the focus detection optical system;
The focus detection module, wherein the center of gravity position of the aperture of the pupil division mask is located closer to the optical axis side of the focus detection optical system than the optical axis of the re-imaging lens. The focus detection module of claim 2.
The optical axis of the re-imaging lens is set at a predetermined angle with respect to the optical axis of the focus detection optical system so that the light beam emitted from the re-imaging lens is substantially parallel to the optical axis of the focus detection optical system. Focus detection module characterized by tilting. The focus detection module according to any one of claims 1 to 3,
If further provided third axis area on the opposite side of the first axis area with respect to the second axis region, and on the opposite side of the first axis area with respect to the second axis region Further, when the third and fourth off-axis regions are provided, in any case, the focus detection optical system is configured so that the light beam passing through the second off-axis region is incident on the light receiving element substantially perpendicularly. A focus detection module. A camera comprising the focus detection module according to claim 1.

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