JP2009192882A - Focus detection device and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine an arrangement and the number of focus detection areas in a photographing screen without being restricted by a photodetector for detecting the position of a mirror. <P>SOLUTION: The focus detection device includes: a microlens array having a plurality of first microlenses arrayed in two dimensions; a photodetection portion array having a plurality of first photodetection portions arrayed in two dimensions to receive light transmitted through the respective microlenses; and a focus detecting arithmetic means of computing a focus adjustment state of an imaging optical system on the basis of outputs of photodetection portions receiving light transmitted through the imaging optical system and reflected by a mirror 12 through the microlens array by the photodetection portion array. The mirror 12 has an index 121a, and includes a pair of second microlenses 521A and 521B having different optical characteristics from the first microlenses and detecting light from the index 121a, and a pair of second photodetection portions 531A and 531B receiving light passed through the pair of second microlenses 521A and 521B. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a focus detection apparatus and an imaging apparatus.

  In an automatic focusing (AF) single-lens reflex camera having a mirror that reflects a light beam that has passed through a photographing lens and guides it to a focus detection device, a mark is attached to the mirror, and the position of this mark is determined by the light receiving element of the focus detection device. There is known a camera that detects a focus position shift due to secular change by detecting an output signal (see, for example, Patent Document 1).

Prior art documents related to the invention of this application include the following.
Japanese Patent Laid-Open No. 2002-098884

  However, the above-described conventional camera has a problem that the arrangement and the number of focus detection areas in the photographing screen are limited by the light receiving element used for detecting the position of the mirror.

(1) The invention of claim 1 is a microlens array in which a plurality of first microlenses are arranged in a two-dimensional manner, and light transmitted through each microlens by arranging a plurality of first light receiving portions in a two-dimensional manner. Calculates the focus adjustment state of the imaging optical system based on the output of the light receiving unit that receives the light received by the light receiving unit array through the microlens array and the light that passes through the imaging optical system and reflected by the mirror And a pair of second microlenses for detecting light from the index having an optical characteristic different from that of the first microlens, and a pair of second microlenses for detecting the light from the index. And a pair of second light receiving portions that receive light respectively transmitted through the second microlenses.
(2) According to a second aspect of the present invention, in the focus detection apparatus according to the first aspect, the pair of second microlenses is disposed between the plurality of first microlenses disposed in the microlens array, and the pair of first microlenses is disposed. The two light receiving units are arranged between the plurality of first light receiving units arranged in the light receiving unit array.
(3) According to a third aspect of the present invention, in the focus detection device according to the first or second aspect, the index is provided on the end surface of the mirror on the microlens array side.
(4) According to a fourth aspect of the present invention, in the focus detection apparatus according to any one of the first to third aspects, a deviation amount between the second microlens and the second light receiving unit corresponding to the second microlens. Is larger than the amount of deviation between the first microlens and the plurality of first light receiving portions corresponding to the first microlens.
(5) According to a fifth aspect of the present invention, in the focus detection device according to any one of the first to fourth aspects, the focal length of the second microlens is longer than the focal length of the first microlens.
(6) According to a sixth aspect of the present invention, in the focus detection apparatus according to any one of the third to fifth aspects, the second light receiving unit and the end surface on which the index of the mirror is provided are the second micro. Conjugated with respect to the lens.
(7) According to a seventh aspect of the invention, in the focus detection apparatus according to any one of the first to sixth aspects, the output of the first light receiving unit is corrected based on the outputs of the pair of second light receiving units. And a correction means for correcting the focus adjustment state.
(8) The invention according to claim 8 is an imaging apparatus including the focus detection apparatus according to any one of claims 1 to 7.

  According to the present invention, it is possible to determine the arrangement and the number of focus detection areas in the photographing screen without being restricted by the light receiving element used for detecting the position of the mirror.

  A focus detection device and an imaging device according to the present invention include a main mirror having a semi-transmissive portion that guides a light beam that has passed through a photographing lens to a finder optical system, and a sub mirror that guides a light beam that has passed through the semi-transmissive portion of the main mirror to a focus detection device. When not shooting, the main mirror and sub mirror are set in the shooting optical path to enable focus detection and viewfinder observation, and during shooting, the main mirror and sub mirror are retracted from the shooting optical path to enable exposure to the image sensor. An embodiment applied to an automatic focusing (AF) single-lens reflex digital still camera will be described.

  FIG. 1 is a cross-sectional view illustrating a configuration of an imaging apparatus according to an embodiment. In FIG. 1, illustration and description of devices and apparatuses other than the devices and apparatuses related to the focus detection apparatus and the imaging apparatus of the present invention are omitted. In a camera according to an embodiment, a lens barrel 2 is detachably attached to a camera body 1, and the lens barrel 2 can be replaced with a lens barrel incorporating various interchangeable lenses.

  The camera body 1 includes a main mirror 11, a sub mirror 12, a filter 13, a shutter 14, an image sensor 15, a focus detection device 16, a penta roof prism 17, an eyepiece lens 18, an electrical contact 19, a body drive control device 20, and the like. The filter 13 is a combination of an optical low-pass filter and an infrared cut filter. The imaging element 15 is composed of a CCD, a CMOS, or the like, and converts the subject image formed by the photographing lens 21 into an electrical signal and outputs it. The focus detection device 16 detects the focus adjustment state of the taking lens 21, that is, the defocus amount. The body drive control device 20 includes a microcomputer (not shown), a ROM, a RAM, an A / D converter, and the like, and performs various camera calculations, sequence control, image sensor drive control, and the like.

  On the other hand, the lens barrel 2 includes a photographing lens 21 (lenses 21a to 21e), a diaphragm 22, a lens drive control device 23, and the like. The lens drive control device 23 includes a microcomputer (not shown), a ROM, a RAM, a lens drive actuator, an aperture drive actuator, and the like, and performs focus adjustment of the taking lens 21, aperture adjustment of the aperture 22, and the like. The body drive control device 20 of the camera body 1 and the lens drive control device 23 of the lens barrel 2 are electrically connected via an electrical contact 19 provided at the mount portion of the interchangeable lens 2, and various information Give and receive.

  At the time of non-photographing, as shown by a solid line in FIG. 1, the main mirror 11 and the sub mirror 12 are placed in the photographing optical path, and part of the subject light transmitted through the photographing lens 21 is the main mirror 11, penta roof prism 17, and eyepiece 18. The subject image is visually recognized by the photographer. The remaining part of the subject light is guided to the focus detection device 16 via the main mirror 11 and the sub mirror 12, and the focus detection device 16 detects the focus adjustment state of the photographing lens 21, that is, the defocus amount.

  At the time of shooting, as indicated by a broken line in FIG. 1, the main mirror 11 and the sub mirror 12 are retracted from the shooting optical path, and a subject image is shot by the image sensor 14. The subject image signal output from the image sensor 14 is processed by an image processing device (not shown), and the subject image is recorded in a recording device such as a memory card (not shown).

  FIG. 2 shows a configuration of a focus detection optical system incorporated in the imaging apparatus according to the embodiment. The photographing lens 21 forms a subject image on the light receiving surface 15a of the image sensor 15 (see FIG. 1). The light beam (focus detection light beam) from the subject that has passed through the photographing lens 21 is reflected by the reflecting surface 12a of the sub mirror 12 (see FIG. 1), and is guided to the planned focal plane 16a conjugate with the imaging element light receiving surface 15a. A subject image is formed on the surface 16a. Note that the focus of the photographic lens 21 is adjusted so that the subject image is focused on the planned focal plane 16a.

  The focus detection device 16 is enclosed in a package 55 in which a microlens array 52 and a light receiving unit array 53 are covered with a cover glass 54.

  Note that a surface (hereinafter referred to as a submirror end surface) 12b parallel to the planned focal plane 16a is formed at the lower end of the submirror 12 (A portion in FIG. 1), and this submirror end surface 12b is in the imaging optical path of the submirror 12 An index for detecting the secular change of the stationary position is drawn. Details of this index will be described later.

  When focus detection is performed using a focus detection light beam at a high image height, the field lens 51 is placed in the optical path, specifically between the vicinity of the planned focal plane 16a and a microlens array 52 described later. It is also possible to insert and bend the light beam at a high image height from the optical axis direction. In the following description, the field lens 51 is ignored.

  FIG. 3 is a front view of the microlens array 52 and the light receiving unit array 53, and is a view seen from the Z direction of FIG. In FIG. 3, the microlens array 52 and the light receiving portion array 53 disposed behind the microlens array 52 are drawn in an overlapping manner, and a light shielding mask provided on the microlens surface is not shown. The light receiving portion array 53 is arranged in the very vicinity behind the microlens array 52, and a plurality of light receiving portions are arranged. In this specification, an example in which a plurality of light receiving units are arranged in association with each microlens is shown, but a plurality of light receiving units may be arranged two-dimensionally regardless of each microlens.

  As shown in FIG. 3, in this embodiment, a microlens for detecting the focus adjustment state of the photographing lens 21 and a plurality of light receiving portions corresponding to each microlens are arranged in five regions in the center in the left-right direction of the photographing screen. In addition, two regions are arranged at the top and bottom of the center and two regions are arranged at the four corners, corresponding to a total of 15 regions. In the upper, lower, left, and right central regions, the light receiving unit rows for each microlens are arranged in the vertical direction and the horizontal direction of the shooting screen. On the other hand, in the four corner areas, the light receiving section rows for each microlens are arranged in the meridional direction and the sagittal direction of the shooting screen.

  On the other hand, the above-described pair of microlenses 521A and 521B for detecting the stationary position of the sub mirror 12 and the light receiving section rows 531A and 531B corresponding to the respective microlenses 521A and 521B are arranged on the upper left and right of the photographing screen. The pair of microlenses 521A and 521B and the pair of light receiving section rows 531A and 531B detect the index drawn on the submirror end face 12b (see FIG. 2), that is, the secular change of the stationary position of the submirror 12 in the photographing optical path. The light from the indicator for receiving is received and a signal corresponding to the position of the submirror is output.

  The sub-mirror position detection microlenses 521A and 521B are processed on the substrate simultaneously with other microlenses. In addition, the light receiving part rows 531A and 531B for detecting the sub mirror are simultaneously processed on the same substrate as the other light receiving parts. There is almost no increase in the number of manufacturing steps for adding these sub-mirror detection microlenses 521A and 521B and the light receiving section rows 531A and 531B to the microlens array 52 and the light receiving section array 53.

  These sub-mirror position detection microlenses 521A and 521B and the light receiving section rows 531A and 531B are for normal focus detection developed in the above-described 15 regions so as not to hinder the focus detection of the photographing lens 21. It arrange | positions in the clearance gap between a micro lens and a light-receiving part row | line | column.

  FIG. 4A shows a microlens and a light receiving unit row in two regions at the upper right corner of the photographing screen shown in FIG. Although not shown in FIG. 3, as shown in FIG. 4A, a light shielding mask 56 is provided on the surface of the microlens array 52 so as to cover portions other than the microlenses. FIG.4 (b) shows the AA cross section of Fig.4 (a). A light shielding film 52 a is coated on the side surface of the microlens array 52. In order to prevent crosstalk of incident light to the microlens, a light shielding partition wall 57 is provided along the boundary between the microlenses. These are formed by digging deep grooves in the glass microlens array 52 by etching or machining, filling them with light-shielding resin, and curing them.

  FIG. 5 is a diagram for explaining a focus detection method by the focus detection device 16 according to the embodiment. In FIG. 5, the illustration of the light shielding partition 57 (see FIG. 4B) is omitted. In this embodiment, a set of one microlens and a light receiving section row corresponding to the microlens is referred to as one pixel. In FIG. 5, pixels having five light receiving portions are arranged for each microlens.

  The image of each light receiving portion of the light receiving portion array 53 by each microlens of the microlens array 52 is connected to the light receiving portion image forming surface 16b slightly closer to the subject side than the vertex of the microlens, and this light receiving portion image forming surface 16b is It is configured to be in the vicinity of the planned focal plane 16a of the camera shown in FIG.

  The focus detection device 16 according to this embodiment is a focus detection device based on a pupil division type phase difference detection method. That is, the defocus amount of the photographing lens 21 is detected based on the positional deviation amount of the pair of subject images formed by the pair of focus detection light beams that have passed through the pair of regions on the pupil plane of the photographing lens 21. A specific focus detection method will be described below.

  The first focus detection method is a method of detecting a defocus amount based on a positional shift amount of a pair of subject images detected by a light receiving unit array of adjacent pixels or every other pixel. A pair of subject images formed on the light receiving unit arrays in the A row and the B row shown in FIG. 5 are "reverse of the light receiving unit array by the microlens" indicated by A 'and B' on the light receiving unit image forming surface 16b. It corresponds to a pair of subject images formed by the imaging lens 21 at the position of “projected image”. Therefore, based on the outputs of the light receiving unit arrays in the A and B rows, the positional deviation amount of the pair of subject images formed by the photographing lens 21 on the light receiving unit image forming surface 16b is detected.

  In the second focus detection method, a composite image represented by a waveform obtained by connecting n-th light-receiving unit outputs from the end of each light-receiving unit array of continuously arranged pixels and (n + m) -th light-receiving unit outputs are represented. In this method, the defocus amount is detected based on the amount of positional deviation from the composite image represented by the connected waveform. As shown in FIG. 5, the image corresponding to the signal sequence connecting the outputs of the second light receiving parts c from the ends of the respective light receiving part arrays of the pixels arranged in succession, and the fourth light receiving part d from the ends. An image corresponding to the signal sequence in which the outputs are connected is formed by the photographing lens 21 at a position of “back projection image of the light receiving portion array by the microlens” indicated by C ′ and D ′ on the light receiving portion image forming surface 16b. Corresponding to a pair of subject images. In other words, the composite images represented by the output waveforms of the discrete light receiving unit row C connected with the light receiving unit c and the discrete light receiving unit row D connected with the light receiving unit d correspond to subject images at positions C ′ and D ′, respectively. . Therefore, based on the outputs of the light receiving portion row C and the light receiving portion row D, the positional deviation amount of the pair of subject images formed by the photographing lens 21 on the light receiving portion image forming surface 16b is detected.

  As a modified example of the second focus detection method, as shown in FIG. 6, a signal sequence obtained by adding the first and second light receiving unit outputs from the ends of the respective light receiving unit arrays of continuously arranged pixels, That is, the output waveform of the light receiving unit row C connected with the combined light receiving unit c and the signal sequence obtained by adding the fourth and fifth light receiving unit outputs from the end, that is, the output waveform of the light receiving unit row D connected with the combined light receiving unit d. Based on this, the positional deviation amount of the pair of subject images formed by the photographing lens 21 on the pixel imaging surface 16b may be detected. That is, the outputs of a plurality of adjacent light receiving units may be combined into a single light receiving unit output.

  FIG. 7 is a block diagram showing a detailed configuration of the focus detection device 16. The output of the light receiving section array 53 (see FIG. 3) is converted into a digital signal by the A / D converter 54 and temporarily stored in the memory 55. The microcomputer 56 includes a composite signal sequence generation unit 56a, an image shift calculation unit 56b, and a focus amount calculation unit 56c in software form, reads out output data of the light receiving unit array 53 from the memory 55, and the composite signal sequence generation unit 56a 1 signal sequence {a (i)} = a (1), a (2), a (3),..., And second signal sequence {b (i)} = b (1), b (2) , B (3),.

  Here, in the case of the first focus detection method described above, the signal sequences {a (i)} and {b (i)} are the light receiving unit outputs of the light receiving unit arrays of the adjacent pixels A and B shown in FIG. It is a line of. Further, in the case of the second focus detection method described above, the signal sequences {a (i)} and {b (i)} are a sequence of outputs of the light receiving unit columns C and D shown in FIG.

Based on the first signal sequence {a (i)} and the second signal sequence {b (i)} obtained in this way, an image shift calculation is performed by a known method to calculate a defocus amount. A method of calculating a defocus amount from two signal sequences {a (i)} and {b (i)} is well known. First, a first signal sequence {a (i)} and a second signal sequence {b (i)} The correlation amount C (N) of the corresponding pair of images is obtained from (i = 1, 2, 3,...).
C (N) = Σ | a (i) −b (j) | (1)
In the equation (1), j−i = N, and N is the number of shifts. Further, Σ represents a total operation of i = pL to qL.

The shift amount is obtained from the correlation amount C (N) obtained discretely by the equation (1) as follows. Here, among the correlation amounts C (N), the correlation amount giving a minimum value when the shift amount N = N0 is C0, the correlation amount in the shift amount (N0-1) is Cr, and the correlation amount in the shift amount (N0 + 1). Let the amount be Cf. A precise shift amount Na is obtained from the arrangement of the correlation amounts Cr, C0, and Cf.
DL = 0.5 · (Cr−Cf) (2),
E = MAX {Cf-C0, Cr-C0) (3),
Na = N0 + DL / E (4)
Next, a correction amount (constant CONST) corresponding to the position of the focus detection surface is added to the shift amount Na to calculate an image shift amount Δn = Na + CONST on the focus detection surface. Further, the defocus amount Df is calculated by multiplying the image shift amount Δn by a constant Kf depending on the detected opening angle.
Df = Kf · Δn (5)

  FIG. 8 is a view of the microlens array 52 and the light receiving unit array 53 viewed from the Z direction in FIG. In FIG. 8, the microlens array 52 and the light receiving portion array 53 disposed behind the microlens array 52 are drawn in an overlapping manner, and the illustration of the light shielding mask 56 (see FIG. 4) provided on the microlens surface is omitted. As described above, in this embodiment, a microlens and a light receiving section row are arranged for each of the 15 areas in the shooting screen, and the focus of the shooting lens 21 is detected. FIG. 9 is an enlarged view of regions B and C in the upper right corner of the microlens array 52 and the light receiving unit array 53 shown in FIG.

  In the four corner areas of the shooting screen, focus detection of the shooting lens 21 is performed in the meridional direction and the sagittal direction of the shooting screen. For example, in the area C shown in FIG. 8, the meridional direction of the shooting screen using the output signals of the pixel rows (microlenses and light receiving portion rows corresponding to the microlenses) on the line segments Cm1, Cm2,. , And focus detection according to the contrast distribution in the sagittal direction of the imaging screen using the output signals of the pixel columns on the line segments Cs1, Cs2,.

  Also in the region B, focus detection is performed according to the contrast distribution in the meridional direction of the photographing screen using the output signals of the pixel columns on the line segments Bm1, Bm2,... And the line segments Bs1, Bs2,. Focus detection is performed according to the contrast distribution in the sagittal direction of the shooting screen using the output signal of the upper pixel row. Similarly, in the two areas of the upper left corner, the lower right corner, and the lower left corner of the shooting screen, focus detection is performed in the meridional direction and the sagittal direction of the shooting screen.

  On the other hand, in the five areas at the center in the left-right direction and the two areas above and below the center, such as areas A and D shown in FIG. Focus detection is performed.

  As described above, the focus detection in the meridional direction and the sagittal direction of the photographing screen is performed, the former can relatively easily correct the aberration of the photographing lens 21, and the latter has a small error due to the aberration of the photographing lens 21, and the photographing lens. This is because the influence of vignetting of a pair of focus detection light beams passing through 21 pupils is small.

  FIG. 10 is a view of the submirror end face 12b (see A part of FIG. 1 and FIG. 2) viewed in the direction opposite to the Z arrow in FIG. 2, and shows an index 121 drawn on the submirror end face 12b. As described above, this index 121 is an index for detecting the secular change of the stationary position in the photographing optical path of the sub mirror 12, and the white line 121a is drawn on the black background 121b by painting. Note that this index may not be provided directly on the sub-mirror 12 but may be provided on a mirror holder that moves integrally with the sub-mirror 12.

  FIG. 11 is a view of the sub mirror 12, the micro lens array 52, and the light receiving unit array 53 as seen from the direction of the arrow Y in FIG. With respect to the white line 121a of the index 121 shown in FIG. 10, the sub-mirror position detection pixel including the microlens 521A and the light-receiving unit row 531A and the sub-mirror position detection pixel including the micro-lens 521B and the light-receiving unit row 531B are described above. According to the first focus detection method, focus detection in the direction of the arrow Z in FIG. 2 is performed. However, the distance between the sub-mirror position detection light receiving section rows 531A and 531B is much larger than the distance between the light receiving section rows A and B described in the first focus detection method described above.

  When adjacent pairs of light receiving section rows used for normal focus detection are used as the light receiving section rows for sub mirror position detection, the distance from the light receiving section array 53 to the index 121 is short, and therefore, on the light receiving section array 53 with respect to the defocus amount. The ratio of image shift becomes small, and the focus detection accuracy becomes low. Therefore, in this embodiment, sufficient focus detection accuracy is ensured by widening the interval between the pair of light receiving section rows for detecting the sub mirror position.

  The difference between a pair of sub-mirror position detection pixels, that is, a pixel made up of the microlens 521A and the light receiving section row 531A and a pixel made up of the microlens 521B and the light receiving section row 531B, and a normal focus detection pixel is as follows. The shift amount (deviation amount) between the center of the microlens and the center of the light receiving section row corresponding to the microlens is larger in the sub-mirror position detection pixel than in the focus detection pixel. In the focus detection pixel, the shift amount generally increases as the distance from the center of the shooting screen, that is, the point intersecting the optical axis of the shooting lens, is larger than the shift of the focus detection pixel. The shift amount is large.

  Second, the conjugate state of the image of the image sensor is different. In the focus detection pixel, the light receiving unit row and the surface 16b in the vicinity of the focus detection surface 16a (see FIG. 5) are conjugate with respect to the microlens. On the other hand, in the sub-mirror position detection pixel, the light receiving section row and the surface of the index 121 are substantially conjugate with respect to the microlens.

  Third, since the sub-mirror position detection pixel and the focus detection pixel are integrally formed, the positions in the Z direction in FIG. 2 are substantially the same, and the magnification is inevitably different from the second difference. Comparing the magnifications of the (back projected image of the light receiving unit row / light receiving unit row), the magnification of the sub mirror position detection pixel is larger than that of the focus detection pixel. For example, the magnification of the sub mirror position detection pixel is 100 times that of the focus detection pixel of 18 times. In other words, the focal length of the micro lens of the sub-mirror position detection pixel is longer than the focal length of the micro lens of the focus detection pixel.

  In this embodiment, since the index 121 for detecting the sub mirror position is provided on the lower end surface 12b of the sub mirror 12, the distance between the index 121 and the light receiving part rows 531A and 531B of the sub mirror position detecting pixels is shortened. The focal length of the micro lenses 521A and 521B of the sub mirror position detection pixel can be minimized. The installation location of the sub mirror position detection index 121 is not limited to the lower end surface 12b of the sub mirror 12. For example, the sub mirror position detection index 121 may be installed on the reflection surface 12a of the sub mirror 12, or may be installed on a holder that moves with the sub mirror 12 as described above. May be.

  Next, the detection result of the index position based on the light receiving unit output of the sub mirror position detection pixel indicates the secular change of the stationary position of the sub mirror 12. The body drive control device 20 (see FIG. 1) compares the index position at the time of factory shipment and the index position detected during use, and refers to a table in which a focus correction value corresponding to the difference is stored in advance or calculated. Ask for. Using this correction value, the focus detection result based on the light receiving unit output of the focus detection pixel is corrected, and the focus detection result of the photographic lens 21 without the focus detection error due to the secular change of the stationary position in the photographic optical path of the sub mirror 12 is obtained. Get.

  The photographer may be warned when the difference between the index position at the time of shipment from the factory and the index position detected during use exceeds a preset alarm threshold value. The photographer sees this warning and can request inspection and repair from a specialized organization.

  In this embodiment, in the camera body 1, an index 121 is provided on the submirror end face 12b, and submirror position detection pixels (521A, 531A), (521B, 531B) are provided in the microlens array 52 and the light receiving section array 53. However, depending on the internal structure of the camera, it may be difficult to identify the index 121 only with the brightness of the subject light. In the camera having such a structure, an illumination lamp such as an LED may be provided to illuminate the indicator 121 and may be turned on when the sub mirror position is detected.

  Note that when near-infrared light is used for illumination, stray light can be prevented from being superimposed on a subject image observed from the optical viewfinder during illumination and difficult to see. In this case, if only the sub-mirror position detection pixel senses near infrared light well and the normal focus detection pixel does not sense much, the influence of the infrared aberration of the photographing lens 21 can be suppressed during focus detection. In addition, there is an advantage that stray light can be prevented from being superimposed on the subject image observed from the optical viewfinder during illumination and difficult to see. Specifically, color absorption filters having different spectral transmittances may be formed on the lower surface of the microlens or on the light receiving portion between the focus detection pixel and the sub-mirror position detection pixel.

  In the embodiment described above, in order to give priority to the focus detection of the photographing lens, the example in which the sub mirror position detection pixels are arranged in the remaining portion where the focus detection pixel area is arranged has been described. Absent.

  In the above-described embodiment, an example in which a plurality of light receiving units under each microlens is arranged in the meridional direction or the sagittal direction has been described. For example, as illustrated in FIG. 12, the plurality of light receiving units are two-dimensionally arranged in both directions. May be deployed. FIG. 12 shows the arrangement of microlenses and light receiving portions in the upper right corner area of the shooting screen. In such an arrangement, the outputs of a plurality of light receiving units connected in a direction perpendicular to the arrangement direction of the microlenses may be combined and used for focus detection calculation as one light receiving unit output in the above-described embodiment. In such a two-dimensional light receiving section arrangement, the arrangement direction of the microlenses can be either the Es direction or the Em direction in FIG. 12, and the same pixel can be used for focus detection in a plurality of directions. .

  Further, the plurality of light receiving portions on the light receiving portion array may be simply arranged in a two-dimensional manner regardless of the meridional direction or the sagittal direction. In such an arrangement, a plurality of light receiving units are handled as one group, a plurality of groups are set along the direction of focus detection, and the above-described focus detection calculation is performed by synthesizing the light receiving unit outputs in each group. Just do it. As an advantage of using the light receiving section array having this configuration, an image sensor generally used for imaging can be used, or an element sharing a manufacturing process with such an image sensor can be used. Further, it is possible to simplify the alignment when the microlens array and the light receiving unit array are bonded together.

Sectional drawing which shows the structure of the imaging device of one embodiment The figure which shows the structure of the focus detection optical system incorporated in the imaging device of one embodiment Front view of microlens array and light receiving unit array The figure which shows the micro lens and light-receiving part row | line | column of two area | regions of the imaging | photography screen upper right corner shown in FIG. The figure for demonstrating the 1st focus detection method by the focus detection apparatus of one embodiment. The figure for demonstrating the 2nd focus detection method by the focus detection apparatus of one embodiment. Block diagram showing the detailed configuration of the focus detection device The figure which looked at the micro lens array and the light-receiving part array from the Z direction of FIG. The figure which expanded the area | region of the upper right corner of the micro lens array and light-receiving part array which are shown in FIG. The figure which looked at the submirror end face in the direction opposite to the Z arrow in FIG. The figure which looked at the submirror, the micro lens array, and the light-receiving part array from the Y arrow direction of FIG. The figure which shows the modification of the light-receiving part arrangement | sequence of a light-receiving part array

Explanation of symbols

12; Submirror, 12a; Reflecting surface, 12b; Submirror end surface, 16; Focus detection device, 20; Body drive control device, 21; Shooting lens, 23; Lens drive control device, 52; Microlens array, 53; 521A, 521B; sub-mirror position detection microlens, 531A, 531B; sub-mirror position detection light receiving element row, 121; index, 121a; white line; 121b;

Claims (8)

A microlens array in which a plurality of first microlenses are arranged two-dimensionally;
A light receiving section array for receiving the light transmitted through each of the microlenses by arranging a plurality of first light receiving sections in a two-dimensional manner;
Focus detection that calculates the focus adjustment state of the imaging optical system based on the output of the light receiving unit that receives the light transmitted through the imaging optical system and reflected by the mirror by the light receiving unit array via the micro lens array In a focus detection device comprising a calculation means,
The mirror includes an indicator;
A pair of second microlenses having optical characteristics different from those of the first microlens and detecting light from the index;
A focus detection apparatus comprising: a pair of second light receiving units that receive light respectively transmitted through the pair of second microlenses. The focus detection apparatus according to claim 1,
The pair of second microlenses are arranged between the plurality of first microlenses arranged in the microlens array, and the pair of second light receiving units are arranged in the light receiving unit array. A focus detection device, which is disposed between the units. The focus detection apparatus according to claim 1 or 2,
A focus detection apparatus, wherein the index is provided on an end surface of the mirror on the microlens array side. In the focus detection apparatus according to any one of claims 1 to 3,
The amount of deviation between the second microlens and the second light receiving unit corresponding to the second microlens is the deviation between the first microlens and the plurality of first light receiving units corresponding to the first microlens. A focus detection device characterized by being larger than a unit amount. In the focus detection apparatus according to any one of claims 1 to 4,
The focus detection apparatus according to claim 1, wherein a focal length of the second microlens is longer than a focal length of the first microlens. In the focus detection apparatus according to any one of claims 3 to 5,
The focus detection apparatus, wherein the second light receiving unit and an end surface of the mirror on which the index is provided are conjugate with respect to the second microlens. In the focus detection apparatus according to any one of claims 1 to 6,
A focus detection apparatus comprising: a correction unit that corrects the focus adjustment state by correcting the output of the first light receiving unit based on the outputs of the pair of second light receiving units.   An imaging apparatus comprising the focus detection apparatus according to claim 1.

Images