JP2013186187A - Focus detection device and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a focus adjustment state of an imaging optical system accurately.SOLUTION: A focus detection device includes a first pair of photoelectric conversion sections arranged side by side in a first direction and a second pair of photoelectric conversion sections arranged side by side in a second direction. The focus detection device comprises: a plurality of photoelectric conversion means PD that are provided corresponding to micro lenses ML respectively; and selection means that selects either the first direction or the second direction as a focus detection direction on the basis of a relation between first pairs of signal strings from the photoelectric conversion means PD corresponding to the plurality of micro lenses ML arranged in the first direction and second pairs of signal strings from the photoelectric conversion means PD corresponding to the plurality of micro lenses ML arranged in a zigzag pattern in the first direction, and a relation between third pairs of signal strings from the photoelectric conversion means PD corresponding to the plurality of micro lenses ML arranged in the second direction and fourth pairs of signal strings from the photoelectric conversion means PD corresponding to the plurality of micro lenses MD arranged in a zigzag pattern in the second direction.

Description

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

  A focus detection device is known that performs focus detection by a phase difference detection method by selecting a direction in which the contrast of a subject is high as a focus detection direction from among a plurality of directions (see Patent Document 1).

JP 2009-198771 A

  In the above-described prior art, even if the contrasts in a plurality of directions are compared with each other, in the case of a subject whose difference is small, the focus detection direction cannot be appropriately determined, and the focus detection accuracy is lowered.

A focus detection apparatus according to a first aspect of the present invention includes a plurality of microlenses arranged two-dimensionally, and a first pair that passes through a first pair of regions of the pupil of the imaging optical system via the microlenses. A first pair of photoelectric conversion units arranged side by side in the first direction so as to receive the first light beam, and a second pair of light beams passing through the second pair of regions of the pupil via the microlens. A second pair of photoelectric conversion units arranged side by side in the second direction, a plurality of photoelectric conversion means provided corresponding to each of the microlenses, and arranged in the first direction First acquisition means for acquiring a first pair of signal sequences from the photoelectric conversion means corresponding to the plurality of microlenses, and the photoelectric conversion corresponding to the plurality of microlenses arranged in a zigzag manner in the first direction. Obtaining a second pair of signal sequences from the means; Acquisition means, third acquisition means for acquiring a third pair of signal sequences from the photoelectric conversion means corresponding to the plurality of microlenses arranged in the second direction, and zigzag arrangement in the second direction A fourth acquisition unit that acquires a fourth pair of signal sequences from the photoelectric conversion unit corresponding to the plurality of microlenses that have been performed, a relationship between the first pair and the second pair of signal sequences, and the third A selection unit that selects one of the first direction and the second direction as a focus detection direction based on a pair and a relationship between the signal pairs of the fourth pair, and the selection unit selects the first direction. In this case, the focus adjustment state of the imaging optical system is detected based on the first pair or the second pair of signal strings, and when the second direction is selected by the selection unit, Third pair or fourth pair Characterized in that it comprises a focus detection means for detecting a focusing state of the imaging optical system based on the column.
According to a ninth aspect of the present invention, there is provided an imaging apparatus according to any one of the first to eighth aspects, and the focus adjustment of the imaging optical system based on the focus adjustment state detected by the focus detection apparatus. And a focus adjusting means for performing the above.

  According to the present invention, it is possible to accurately detect the focus adjustment state of the imaging optical system.

It is a figure which illustrates the structure of the digital camera by embodiment of this invention. It is a figure which illustrates the composition of a focus detection sensor. It is a figure explaining the photoelectric conversion element row | line used for AF calculation. It is a figure explaining a focus detection direction. It is a figure which shows an example of a to-be-photographed image. (A) is a diagram for explaining the microlens row H1, (B) is a diagram for explaining the microlens row R1, and (C) is a diagram for explaining the microlens row L1. (A) is a figure explaining the output value of the output signal row | line | column corresponding to micro lens row | line | column H1, (B) is a figure explaining the output value of the output signal row | line | column corresponding to micro lens row | line | column R1, (C) is a figure explaining the output value of the output signal row | line | column corresponding to the micro lens row | line | column L1. It is a figure explaining the correlation amount of a pair of output signal row | line | column corresponding to micro lens row | line | column H1, R1, and L1. (A) is a figure explaining micro lens row | line | column H2, (B) is a figure explaining micro lens row | line | column R2, (C) is a figure explaining micro lens row | line | column L2. (A) is a figure explaining the output value of the output signal row | line | column corresponding to micro lens row | line | column H2, (B) is a figure explaining the output value of the output signal row | line | column corresponding to micro lens row | line | column R2, (C) is a figure explaining the output value of the output signal row corresponding to micro lens row L2. It is a figure explaining the correlation amount of a pair of output signal row | line | column corresponding to micro lens row | line | column H2, R2, and L2. It is a flowchart explaining the flow of AF calculation processing. It is a flowchart explaining the flow of the focus detection direction determination process in 1st Embodiment. It is a flowchart explaining the flow of the focus detection direction determination process in 2nd Embodiment. It is a figure explaining the micro lens row | line | column used in the modification 2. FIG. It is a figure explaining the focus detection direction in the modification 3. (A) is a figure explaining the micro lens rows H1 and V1 used in the modified example 4, and (B) is a diagram explaining the micro lens rows H2 and V2 used in the modified example 4.

(First embodiment)
A first embodiment according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of a digital camera to which the present invention is applied. It should be noted that illustrations and descriptions of general devices and apparatuses of cameras other than the devices and apparatuses according to the present invention are omitted. In the digital camera of the present embodiment, the lens barrel 2 including the photographing lens 20 is attached to the camera body 1. The lens barrel 2 can be exchanged.

  The camera body 1 is provided with a half mirror 10. An imaging element 11 is disposed behind the half mirror 10, and a focus detection sensor 12 is disposed above the half mirror 10. Further, an EVF (electronic viewfinder) 13 is provided on the upper portion of the camera body 1. Further, the camera body 1 is provided with a control device 14.

  The half mirror 10 is an optical member for dividing transmitted light and reflected light, and for example, a thin mirror such as a pellicle mirror is used. The image sensor 11 and the focus detection sensor 12 are each composed of a CCD, a CMOS, or the like, and are arranged on the planned focal plane of the photographic lens 20. The image sensor 11 and the focus detection sensor 12 each convert the subject image formed by the photographing lens 20 into an electrical signal and output it. The EVF 13 displays an image captured by the image sensor 11 on a liquid crystal display element so that a photographer can visually recognize the image. The control device 14 includes a microcomputer (not shown), a ROM, a RAM, an A / D converter, and the like. The focus detection sensor 12 and the control device 14 constitute a phase difference detection type focus detection device, and calculate a defocus amount indicating the focus adjustment state of the photographic lens 20.

  The lens barrel 2 includes a photographic lens 20, a lens driving unit 21, and the like. The lens driving unit 21 drives the photographing lens 20 by an actuator (not shown). The control device 14 of the camera body 1 and the lens driving unit 21 of the lens barrel 2 are electrically connected via a contact (not shown), and exchange various information.

  Part of the subject light that has passed through the photographic lens 20 passes through the half mirror 10 and is guided to the image sensor 11, and is imaged by the image sensor 11. The image signal output from the image sensor 11 is written in a recording medium (not shown) such as a memory card after predetermined signal processing. The image signal output from the image sensor 11 is displayed on the EVF 13 after being subjected to predetermined signal processing.

  The remaining part of the subject light transmitted through the photographing lens 20 is reflected by the half mirror 10 and guided to the focus detection sensor 12. The control device 14 calculates the defocus amount based on the output signal from the focus detection sensor 12, calculates the driving amount of the focusing lens in the photographing lens 20 based on the defocus amount, and outputs it to the lens driving unit 21. To do. The lens driving unit 21 drives the focusing lens based on this driving amount and moves it to the in-focus position.

-Configuration of focus detection sensor-
FIG. 2A is a perspective view illustrating a detailed configuration of the focus detection sensor 12, and FIG. 2B is a front view illustrating a detailed configuration of the focus detection sensor 12. The focus detection sensor 12 includes a microlens array 121 and a photoelectric conversion element array 122. Note that although the photoelectric conversion element array 122 is arranged in the very vicinity behind the microlens array 121, it is shown apart from the actual one in FIG.

  The microlens array 121 has a configuration in which a plurality of microlenses ML are two-dimensionally arranged, and is arranged in the vicinity of the surface on which the photographing lens 20 is to be focused, that is, the surface equivalent to the imaging surface of the image sensor 11. Is done. The microlenses ML are arranged with a half-pitch shift for each row. That is, the microlens ML is configured such that the positions of the odd rows and the even rows are shifted by a half pitch. Note that the pitch of the microlenses ML is, for example, 100 μm or less. Further, although the microlens ML is described as a spherical shape in FIG. 2, the microlens ML may be arranged in a honeycomb structure as a regular hexagon so as to be configured with higher density.

  In the photoelectric conversion element array 122, photoelectric conversion element groups PD in which a plurality of photoelectric conversion elements are two-dimensionally arranged are two-dimensionally arranged so as to correspond to the respective microlenses ML. In FIG. 2, a photoelectric conversion element group PD composed of 25 photoelectric conversion elements arranged in 5 rows and 5 columns is provided corresponding to one microlens ML. The number of corresponding photoelectric conversion elements is not limited to the number of this embodiment.

-AF calculation by phase difference detection method-
In the present embodiment, AF calculation is performed by a pupil division type phase difference detection method. In the pupil division type phase difference detection method, a well-known correlation operation is performed on a pair of output signal sequences obtained by connecting outputs of a pair of photoelectric conversion elements that receive a pair of light beams that have passed through a pair of regions of the pupil of the photographing lens 20. The image shift amount (shift amount) is obtained. Then, the defocus amount is calculated based on the image shift amount.

  For example, when obtaining the image shift amount in the horizontal direction, as shown in FIG. 3, in the photoelectric conversion element group PD corresponding to the microlens ML, the output of the photoelectric conversion element array composed of a pair of photoelectric conversion elements arranged in the horizontal direction. Signal sequences {a (i)} and {b (i)} (i = 1, 2, 3,...) Are used.

  Specifically, when the photographic lens 20 has an open F value, the detection opening angle α is wide as shown in FIG. 3A, and therefore, for example, the photoelectric conversion element p1 at the left end of each photoelectric conversion element group PD is included. The output signal sequence {a (i)} of the photoelectric conversion element array and the output signal sequence {b (i)} of the photoelectric conversion element array including the photoelectric conversion element p5 at the right end of each photoelectric conversion element group PD are used. Actually, as shown in FIG. 3B, in each photoelectric conversion element group PD, an output signal sequence {a (i)} obtained by averaging the output signals of the central three photoelectric conversion elements in the left end column, In the photoelectric conversion element group PD, an output signal string {b (i)} obtained by averaging the output signals of the central three photoelectric conversion elements in the right end column is used.

  Further, as the aperture diameter becomes smaller than the open F value, as shown in FIG. 3C, the detection opening angle α becomes narrower. For example, the second photoelectric conversion element p2 from the left of each photoelectric conversion element group PD. Output signal sequence {a (i)} of the photoelectric conversion element array composed of and output signal string {b (i)} of the photoelectric conversion element array composed of the second photoelectric conversion element p4 from the right of each photoelectric conversion element group PD And are used. Actually, as shown in FIG. 3D, in each photoelectric conversion element group PD, an output signal sequence {a (i) obtained by averaging the output signals of the three central photoelectric conversion elements in the second column from the left. } And an output signal sequence {b (i)} obtained by averaging the output signals of the center three photoelectric conversion elements in the second column from the right in each photoelectric conversion element group PD.

In the correlation calculation in the AF calculation, the correlation in the shift amount k between the two signal strings is calculated by the expression (1) while relatively shifting the output signal string {b (i)} with respect to the output signal string {a (i)}. The quantity C (k) is calculated. In the equation (1), Σ represents a total calculation of a predetermined range related to i.
C (k) = Σ | a (i) −b (i + k) | (1)

The calculation result of the expression (1) shows that the correlation amount C (k) is the smallest (the smaller the correlation is, the higher the degree of correlation is) in the shift amount having the highest correlation between the pair of output signal sequences {a (i)} and {b (i)}. ) When the shift amount kj that is the minimum correlation amount C (kj) is obtained from the calculation result of the equation (1), a continuous three-point interpolation method according to the following equations (2) to (5) is used. A shift amount x that gives a minimum value C (x) with respect to the correlation amount is obtained.
x = kj + D / S (2)
C (x) = C (kj) − | D | (3)
D = {C (kj−1) −C (kj + 1)} / 2 (4)
S = MAX {C (kj + 1) -C (kj), C (kj-1) -C (kj)} (5)

The defocus amount DEF of the photographing lens 20 can be obtained from the following equation (6) from the shift amount x obtained from the equation (2).
DEF = KX · PY · x (6)
In Equation (6), PY is a detection pitch, and KX is a conversion coefficient determined by the magnitude of the detection opening angle.

-Focus detection direction determination process-
By the way, as described above, the microlenses ML of the focus detection sensor 12 are arranged so as to be shifted by a half pitch for each row. Therefore, the direction in which the pitch width of the microlens ML is the narrowest (that is, the direction in which focus detection can be performed with the highest accuracy) is the horizontal direction H and a direction rotated 60 degrees counterclockwise from the horizontal direction H (see FIG. 4). Hereinafter, there are three directions: R, which is referred to as an oblique right direction, and R, which is a direction rotated 60 degrees clockwise from the horizontal direction H (hereinafter, referred to as an oblique left direction).

  In the phase difference detection method, focus detection accuracy is higher when focus detection is performed in a direction perpendicular to the edge of the subject. Therefore, in the digital camera of the present embodiment, when performing AF calculation processing, the focus detection that determines the direction closest to the direction perpendicular to the edge of the subject from the three directions H, R, and L, and determines it as the focus detection direction. Perform direction determination processing.

  Here, the focus detection direction determination process will be described by taking as an example the case where the subject image Im has a vertical edge as shown in FIG. First, the control device 14 obtains contrasts in the output signal rows of the photoelectric conversion element rows corresponding to the three microlens rows H1, R1, and L1 shown in FIG. In FIG. 6, for the sake of explanation, the photoelectric conversion elements that use the output signal are shown in black, and the subject image Im that is incident on the microlens ML and the photoelectric conversion element group PD is shown in an overlapping manner. Further, in FIG. 6, an output signal from one photoelectric conversion element is illustrated as being used as one output signal (a1, b1, a2, b2,...). An average value of output signals from the photoelectric conversion elements is used as one output signal. Furthermore, actually, as described above, the photoelectric conversion element array used also differs depending on the magnitude of the detection opening angle.

  As shown in FIG. 6A, the microlens row H1 includes a plurality of microlenses ML arranged in a row in the horizontal direction H. The control device 14 outputs an output signal sequence {a (i)} and {b of a photoelectric conversion element array including a pair of photoelectric conversion elements arranged in the horizontal direction H in the photoelectric conversion element group PD disposed behind the microlens array H1. (I)} is used to calculate the correlation according to the above equation (1). Then, the shift amount x is obtained by the above equations (2) to (5) using the above three-point interpolation method. At this time, the difference between S (minimum correlation amount C (kj)) obtained by the equation (5) and the adjacent correlation amount C (kj + 1) or C (kj−1), that is, in the vicinity of the minimum correlation amount C (kj). The slope of the correlation amount C (k) is a value proportional to the contrast. Therefore, this S is used as a contrast value in the focus detection direction determination process of the present embodiment.

  As shown in FIG. 6B, the microlens array R1 includes a plurality of microlenses ML arranged in a line in the right diagonal direction R. The control device 14 outputs an output signal sequence {a (i)} of a photoelectric conversion element array composed of a pair of photoelectric conversion elements arranged in a substantially right oblique direction R in the photoelectric conversion element group PD disposed behind the microlens array R1. The correlation calculation is performed using {b (i)}. Then, the shift amount x is obtained and the contrast value S is obtained using the above three-point interpolation method.

  As shown in FIG. 6C, the microlens array L1 includes a plurality of microlenses ML arranged in a line in the diagonally left direction L. The control device 14 outputs an output signal string {a (i)} of a photoelectric conversion element array composed of a pair of photoelectric conversion elements arranged in a substantially left oblique direction L in the photoelectric conversion element group PD disposed behind the microlens array L1. The correlation calculation is performed using {b (i)}. Then, the shift amount x is obtained and the contrast value S is obtained using the above three-point interpolation method.

  FIG. 7A is a graph showing output values of the output signal sequences {a (i)} and {b (i)} corresponding to the microlens column H1. FIG. 7B is a graph showing output values of the output signal sequences {a (i)} and {b (i)} corresponding to the microlens array R1. FIG. 7C is a graph showing output values of the output signal sequences {a (i)} and {b (i)} corresponding to the microlens array L1. FIGS. 7A to 7C show an example in which the output signal sequences {a (i)} and {b (i)} have the highest correlation.

  As shown in FIGS. 6A to 6C, since each microlens array H1, R1, and L1 extends over the edge portion of the subject image Im, as shown in FIGS. In the output signal trains {a (i)} and {b (i)} corresponding to the respective microlens rows H1, R1, and L1, the output values greatly change at the edge portions.

  FIG. 8 is a graph showing the correlation amounts C (k) of the output signal sequences {a (i)} and {b (i)} corresponding to the microlens rows H1, R1, and L1, respectively. In FIG. 8, the contrast value corresponding to the microlens row H1 is shown as S (H1), the contrast value corresponding to the microlens row R1 is shown as S (R1), and the contrast value corresponding to the microlens row L1 is shown as S (L1). . As shown in the equation (5), the contrast value S is the difference between the minimum correlation amount C (kj) and the adjacent correlation amount C (kj + 1) or C (kj−1) (that is, the minimum correlation amount). The slope of the correlation amount C (k) in the vicinity of the amount C (kj)).

  As shown in FIG. 8, the contrast values S (H1), S (R1), and S (L1) are close to each other. As shown in FIGS. 7A to 7C, the output signal sequences {a (i)} and {b (i)} corresponding to the microlens columns H1, R1, and L1 are output values. This is because the ways of change are close to each other.

  In the phase difference detection method, the detection accuracy of the defocus amount is higher when the image shift amount (shift amount) is detected in the direction perpendicular to the edge (here, the horizontal direction H). However, in the case of the subject shown in FIG. 5, as described above, the contrast values S (H1), S (R1), and S (L1) corresponding to the microlens rows H1, R1, and H1 are close to each other. Therefore, it is difficult to determine an appropriate focus detection direction only by comparing these.

  Therefore, in the present embodiment, the contrast value S is also obtained for each of the output signal rows of the photoelectric conversion element rows corresponding to the microlens rows H2, R2, and L2 shown in FIG. In FIG. 9 as well, for the sake of explanation, the photoelectric conversion elements that use the output signals are shown in black, and the subject image Im that is incident on the microlens ML and the photoelectric conversion element group PD is also superimposed. Further, in FIG. 6, an output signal from one photoelectric conversion element is illustrated as being used as one output signal (a1, b1, a2, b2,...). An average value of output signals from the photoelectric conversion elements is used as one output signal. Furthermore, actually, as described above, the photoelectric conversion element array used also differs depending on the magnitude of the detection opening angle.

  As shown in FIG. 9A, the microlens array H2 includes a plurality of microlenses ML arranged in a zigzag manner in the horizontal direction H. In the microlens row H2, the microlenses ML are arranged so as to be shifted by a half pitch. The control device 14 outputs an output signal sequence {a (i)} and {b of a photoelectric conversion element array composed of a pair of photoelectric conversion elements arranged in the horizontal direction H in the photoelectric conversion element group PD arranged behind the microlens array H2. (I)} is used to perform the correlation calculation. Then, the shift amount x is obtained and the contrast value S is obtained using the above three-point interpolation method.

  As shown in FIG. 9B, the microlens array R2 includes a plurality of microlenses ML arranged in a zigzag manner in the diagonally right direction R. Also in the microlens row R2, the microlenses ML are arranged shifted by a half pitch. The control device 14 outputs an output signal string {a (i)} of a photoelectric conversion element array composed of a pair of photoelectric conversion elements arranged in a substantially right oblique direction R in the photoelectric conversion element group PD disposed behind the microlens array R2. The correlation calculation is performed using {b (i)}. Then, the shift amount x is obtained and the contrast value S is obtained using the above three-point interpolation method.

  As shown in FIG. 9C, the microlens array L2 includes a plurality of microlenses ML arranged in a zigzag manner in the left oblique direction L. Also in the microlens row L2, the microlenses ML are arranged so as to be shifted by a half pitch. The control device 14 outputs an output signal sequence {a (i)} of a photoelectric conversion element array composed of a pair of photoelectric conversion elements arranged in a substantially left oblique direction L in the photoelectric conversion element group PD disposed behind the microlens array L2. The correlation calculation is performed using {b (i)}. Then, the shift amount x is obtained and the contrast value S is obtained using the above three-point interpolation method.

  FIG. 10A is a graph showing output values of the output signal sequences {a (i)} and {b (i)} corresponding to the microlens column H2. FIG. 10B is a graph showing output values of the output signal sequences {a (i)} and {b (i)} corresponding to the microlens array R2. FIG. 10C is a graph showing the output values of the output signal sequences {a (i)} and {b (i)} corresponding to the microlens array L2. FIGS. 7A to 7C show an example in which the output signal sequences {a (i)} and {b (i)} have the highest correlation.

  As shown in FIG. 9A, in the microlens array H2, the portion corresponding to the output signals a (5) to a (6) extends over the edge portion of the subject image Im. As shown, the output value of the output signal sequence {a (i)} corresponding to the microlens array H2 changes significantly at the edge portion. The same applies to the output signal sequence {b (i)} corresponding to the microlens array H2.

  On the other hand, as shown in FIG. 9B, in the microlens array R2, the edge portion of the subject image Im crosses from the left to the right at the portion corresponding to the output signals a (3) to a (4), but is output again. In the portion corresponding to the signal a (5), the edge portion spans from right to left, and in the portion corresponding to the output signal a (6) again, the edge portion straddles from left to right. Therefore, as shown in FIG. 10B, in the output signal sequence {a (i)} corresponding to the microlens array R2, the output value of the edge portion oscillates up and down as much as one edge portion is straddled multiple times. It has changed. The same applies to the output signal sequence {b (i)} corresponding to the microlens array R2.

  Similarly, in the microlens array L2 shown in FIG. 9C, the edge portion of the subject image Im crosses from the left to the right at the portion corresponding to the output signals a (7) to a (8), but the output signal again. The edge portion spans from right to left at the portion corresponding to a (9), and the edge portion straddles from left to right again at the portion corresponding to output signal a (10). Therefore, as shown in FIG. 10C, even in the output signal sequence {a (i)} corresponding to the microlens array L2, the output value of the edge portion oscillates up and down as much as one edge portion is straddled. It has changed. The same applies to the output signal sequence {b (i)} corresponding to the microlens array L2.

  FIG. 11 is a graph showing the correlation amounts C (k) of the output signal sequences {a (i)} and {b (i)} corresponding to the microlens rows H2, R2, and L2. In FIG. 11, the contrast value corresponding to the microlens row H2 is shown as S (H2), the contrast value corresponding to the microlens row R2 is shown as S (R2), and the contrast value corresponding to the microlens row L2 is shown as S (L2). . As shown in the equation (5), the contrast value S is the difference between the minimum correlation amount C (kj) and the adjacent correlation amount C (kj + 1) or C (kj−1) (that is, the minimum correlation amount). The slope of the correlation amount C (k) in the vicinity of the amount C (kj)).

  In the output signal trains {a (i)} and {b (i)} corresponding to the microlens rows R2 and L2, the output values change while oscillating up and down as shown in FIGS. 10 (B) and (C). As a result, the contrast decreases. Therefore, as shown in FIG. 11, the correlation amount C (k) corresponding to the microlens rows R2 and L2 is smaller than the correlation amount C (k) corresponding to the microlens row H2. Further, the contrast values S (R2) and S (L2) corresponding to the microlens rows R2 and L2 are also smaller than the contrast value S (H2) corresponding to the microlens row H2.

  Furthermore, the contrast value S (H2) corresponding to the microlens array H2 and the contrast value S (H1) corresponding to the microlens array H1 shown in FIG. 8 are close to each other. However, the contrast value S (R2) corresponding to the microlens row R2 is much smaller than the contrast value S (R1) corresponding to the microlens row R1 shown in FIG. Similarly, the contrast value S (L2) corresponding to the microlens row L2 is much smaller than the contrast value S (L1) corresponding to the microlens row L1 shown in FIG.

  Thus, in the direction perpendicular to the edge of the subject (here, the horizontal direction H), the contrast values S corresponding to the microlens rows H1 and H2 are close to each other. On the other hand, in the direction away from the direction perpendicular to the edge of the subject (here, the right oblique direction R and the left oblique direction L), the microlens row R2 or the contrast value S corresponding to the microlens row R1 or L1 is compared. The contrast value S corresponding to L2 becomes considerably small.

  Therefore, in the focus detection direction determination process of the present embodiment, the contrast values S corresponding to the microlens rows H1 and H2, R1 and R2, and L1 and L2 are compared. As a result of this comparison, the direction in which the contrast values S are closest to each other is estimated to be the direction closest to the direction perpendicular to the edge of the subject, and is determined as the focus detection direction.

  Next, the flow of AF calculation processing executed by the control device 14 of the camera body 1 will be described using the flowchart shown in FIG. In step S101, the control device 14 determines whether or not an AF start switch (SW1) (not shown) is turned on. If the AF activation switch is turned on, the control device 14 makes a positive determination in step S101 and proceeds to step S102. On the other hand, if the AF activation switch is not turned on, the control device 14 makes a negative determination in step S101 and repeats the determination process in step S101.

  In step S102, the control device 14 performs accumulation control of the focus detection sensor 12, and proceeds to step S103.

  In step S103, the control device 14 reads the light reception signal from the focus detection sensor 12, and proceeds to step S104.

  In step S104, the control device 14 performs the above correlation calculation based on the output signal sequences {a (i)} and {b (i)} corresponding to the microlens rows H1, R1, and L1 as described above, and performs the decoding. The focus amount is calculated, and the process proceeds to step S105.

  In step S105, the control device 14 performs the above correlation calculation based on the output signal sequences {a (i)} and {b (i)} corresponding to the microlens columns H2, R2, and L2, as described above, and performs the decoding. The focus amount is calculated, and the process proceeds to step S106.

  In step S106, the control device 14 performs the focus detection direction determination process described above. Here, the flow of the focus detection direction determination process will be described with reference to the flowchart shown in FIG. In step S201, the control device 14 determines the contrast value S (H1) obtained when calculating the defocus amount corresponding to the microlens row H1, and the contrast value S obtained when calculating the defocus amount corresponding to the microlens row H2. Compare with (H2). Specifically, the ratio of the contrast value S (H2) of the microlens row H2 to the contrast value S (H1) of the microlens row H1 is calculated, and the process proceeds to step S202.

  In step S202, the control device 14 determines the contrast value S (R1) obtained when calculating the defocus amount corresponding to the microlens row R1, and the contrast value S obtained when calculating the defocus amount corresponding to the microlens row R2. (R2) is compared. Specifically, the ratio of the contrast value S (R2) of the microlens row R2 to the contrast value S (R1) of the microlens row R1 is calculated, and the process proceeds to step S203.

  In step S203, the control device 14 determines the contrast value S (L1) obtained when calculating the defocus amount corresponding to the microlens row L1, and the contrast value S obtained when calculating the defocus amount corresponding to the microlens row L2. (L2) is compared. Specifically, the ratio of the contrast value S (L2) of the microlens row L2 to the contrast value S (L1) of the microlens row L1 is calculated, and the process proceeds to step S204.

  In step S204, the control device 14 determines whether or not the ratio of the contrast value S (H2) of the microlens row H2 to the contrast value S (H1) of the microlens row H1 is the maximum. When the ratio of the contrast value S (H2) of the microlens row H2 to the contrast value S (H1) of the microlens row H1 is the maximum among the calculation results of steps S201 to S203, the control device 14 affirms step S204. Determine and proceed to step S205. On the other hand, when the other calculation result is the maximum among the calculation results of steps S201 to S203, the negative determination is made in step S204 and the process proceeds to step S206.

  In step S205, the control device 14 determines the horizontal direction H as the focus detection direction, and determines the defocus amount obtained from the output signal sequences {a (i)} and {b (i)} corresponding to the microlens column H1. Then, it is determined as the defocus amount used for focus adjustment, and the processing of FIG.

  On the other hand, in step S206, the control device 14 determines whether or not the ratio of the contrast value S (R2) of the microlens row R2 to the contrast value S (R1) of the microlens row R1 is the maximum. When the ratio of the contrast value S (R2) of the microlens row R2 to the contrast value S (R1) of the microlens row R1 is the maximum among the calculation results of steps S201 to S203, the control device 14 affirms step S206. Determine and proceed to step S207. On the other hand, if the ratio of the contrast value S (L2) of the microlens row L2 to the contrast value S (L1) of the microlens row L1 is the maximum among the calculation results of steps S201 to S203, a negative determination is made in step S206. Then, the process proceeds to step S208.

  In step S207, the control device 14 determines the right oblique direction R as the focus detection direction, and the defocus amount obtained from the output signal sequences {a (i)} and {b (i)} corresponding to the microlens array R1. Is determined as the defocus amount used for focus adjustment, and the process of FIG. 13 is terminated.

  On the other hand, in step S208, the control device 14 determines the left oblique direction L as the focus detection direction, and obtains the data obtained from the output signal sequences {a (i)} and {b (i)} corresponding to the microlens array L1. The focus amount is determined as the defocus amount used for focus adjustment, and the processing in FIG.

  When the control device 14 performs the focus detection direction determination process of FIG. 13 in this way, the process proceeds to step S107 (FIG. 12). In step S107, the control device 14 calculates the lens driving amount to the focusing position of the focusing lens based on the defocus amount determined in step S106, and the process proceeds to step S108.

  In step S108, the control device 14 determines whether or not the focusing lens has reached the in-focus position. If the focusing lens has reached the in-focus position, an affirmative decision is made in step S108 and the processing in FIG. On the other hand, if the focusing lens has not reached the in-focus position, a negative determination is made in step S108, and the process proceeds to step S109.

  In step S109, the control device 14 outputs the lens driving amount calculated in step S107 to the lens driving unit 21, drives the focusing lens by the lens driving unit 21, and returns to step S101. In step S104 described above, if the control device 14 determines that the focus cannot be detected during the defocus amount calculation corresponding to the microlens rows H1, R1, and L1, the lens driving unit 21 causes the focusing lens to reach the focusing lens. An in-focus position is searched by performing an operation (so-called scanning operation) that is driven between the near end and the infinity end. If the subject is lost while the focusing lens is being moved by the lens driving unit 21, the control device 14 continues driving the focusing lens based on the previously detected defocus amount.

According to the first embodiment described above, the following operational effects can be obtained.
(1) The focus detection apparatus of this embodiment includes a plurality of microlenses ML arranged in a two-dimensional manner. In addition, the focus detection device receives a first pair of light beams that have passed through the first pair of regions of the pupil of the photographing lens 20 through the microlens ML, and is arranged in a horizontal direction H so as to receive the first pair of light beams. A second pair of photoelectric elements arranged in the diagonally right direction R so as to receive the second pair of light beams that have passed through the second pair of regions of the pupil of the photographing lens 20 through the photoelectric conversion unit and the microlens ML. A third pair of photoelectric conversions arranged side by side in the left diagonal direction L so as to receive the third pair of light beams that have passed through the third pair of regions of the pupil of the photographing lens 20 via the conversion unit and the microlens ML. And a plurality of photoelectric conversion element groups PD provided corresponding to each of the microlenses ML. Further, the focus detection device acquires a first pair of signal sequences from the photoelectric conversion element group PD corresponding to the micro lens rows H1 arranged in the horizontal direction H, and the micro lens rows H2 arranged in a zigzag manner in the horizontal direction H. Is provided with a control device 14 that obtains a second pair of signal sequences from the photoelectric conversion element group PD corresponding to. Furthermore, the focus detection apparatus acquires a third pair of signal sequences from the photoelectric conversion element group PD corresponding to the microlens array R1 arranged in the right oblique direction R, and the microlenses arranged zigzag in the right oblique direction R. A control device 14 is provided for acquiring a fourth pair of signal strings from the photoelectric conversion element group PD corresponding to the string R2. Further, the focus detection apparatus acquires a fifth pair of signal arrays from the photoelectric conversion element group PD corresponding to the microlens array L1 arranged in the left oblique direction L, and the microlenses arranged zigzag in the left oblique direction L. A control device 14 is provided that acquires a sixth pair of signal strings from the photoelectric conversion element group PD corresponding to the string L2. Further, the focus detection device is based on the relationship between the first and second pairs of signal sequences, the relationship between the third and fourth pairs of signal sequences, and the relationship between the fifth and sixth pairs of signal sequences. And a control device 14 that selects any one of the horizontal direction H, the diagonally right direction R, and the diagonally left direction L as the focus detection direction. Further, when the horizontal direction H is selected, the focus detection device detects the focus adjustment state of the photographic lens 20 based on the first pair of signal sequences, and when the right diagonal direction R is selected, the focus detection device 3 A control device that detects the focus adjustment state of the photographic lens 20 based on the pair of signal sequences and detects the focus adjustment state of the photographic lens 20 based on the fifth pair of signal sequences when the left diagonal direction L is selected. 14. Thereby, since a focus detection direction can be determined appropriately, focus detection of the photographing lens 20 can be performed with high accuracy.

(2) In the focus detection apparatus according to (1), the control device 14 calculates the first contrast value S (H1) from the first pair of signal sequences, and the second contrast value S ( H2), a third contrast value S (R1) is calculated from the third pair of signal sequences, a fourth contrast value S (R2) is calculated from the fourth pair of signal sequences, and a fifth pair of signal sequences is calculated. The fifth contrast value S (L1) is calculated from the sixth contrast value S, and the sixth contrast value S (L2) is calculated from the sixth pair of signal sequences. Further, the control device 14 determines the relationship between the magnitudes of the first contrast value S (H1) and the second contrast value S (H2), and the magnitudes of the third contrast value S (R1) and the fourth contrast value S (R2). The horizontal direction H, the right diagonal direction R, and the left diagonal direction L are determined based on the relationship between the horizontal direction H, the right contrast direction S, and the sixth contrast value S (L2). The focus detection direction is selected. Thereby, the direction closest to the direction perpendicular to the edge of the subject can be selected as the focus detection direction.

(3) In the focus detection device of (2), the control device 14 determines that the ratio of the second contrast value S (H2) to the first contrast value S (H1) is the fourth contrast value to the third contrast value S (R1). When the ratio of the contrast value S (R2) and the ratio of the sixth contrast value S (L2) to the fifth contrast value S (L1) are larger, the horizontal direction H is selected as the focus detection direction. Further, the control device 14 determines that the ratio of the fourth contrast value S (R2) to the third contrast value S (R1) is equal to the ratio of the second contrast value S (H2) to the first contrast value S (H1) and the fifth contrast value S (R1). When the ratio is larger than the ratio of the sixth contrast value S (L2) to the contrast value S (L1), the right diagonal direction R is selected as the focus detection direction. Further, the control device 14 determines that the ratio of the sixth contrast value S (L2) to the fifth contrast value S (L1) is equal to the ratio of the fourth contrast value S (R2) to the third contrast value S (R1). When the ratio is larger than the ratio of the second contrast value S (H2) to the contrast value S (H1), the left diagonal direction L is selected as the focus detection direction. Thereby, the direction closest to the direction perpendicular to the edge of the subject can be selected as the focus detection direction.

(Second Embodiment)
The flow of the focus detection direction determination process in the second embodiment of the present invention will be described using the flowchart shown in FIG. The second embodiment is the same as the first embodiment except for the focus detection direction determination process, and a description thereof will be omitted.

  In steps S301 to S303 in FIG. 14, the control device 14 performs the same processing as in steps S201 to S203 in FIG. 13 described above, and proceeds to step S304. In step S304, the control device 14 determines that the ratio of the contrast value S calculated in steps S301 to S303 is greater than or equal to a predetermined threshold (for example, 80%) in all three directions of the horizontal direction H, the right diagonal direction R, and the left diagonal direction L. It is determined whether or not. If the ratio of the contrast values S in all three directions is equal to or greater than the predetermined threshold, the control device 14 makes a positive determination in step S304 and proceeds to step S305. On the other hand, when the ratio of the contrast value S is less than the predetermined threshold in at least one direction, the control device 14 makes a negative determination in step S304 and proceeds to step S306.

  When the ratio of the contrast values S in all three directions is equal to or greater than a predetermined threshold, it is assumed that there is little difference in detection accuracy regardless of whether the focus is detected in any of the three directions. Therefore, in step S305, the control device 14 determines all three directions of the horizontal direction H, the right diagonal direction R, and the left diagonal direction L as focus detection directions. Then, the control device 14 determines the defocus amount obtained from the image shift amounts in the horizontal direction H, the right oblique direction R, and the left oblique direction L (defocus amount obtained from the output signal sequence corresponding to the microlens arrays H1, R1, and L1. ) Is determined as a defocus amount used for focus adjustment. Thereafter, the processing in FIG. 14 is terminated.

  On the other hand, in step S306, the control device 14 determines whether or not the ratio of the contrast value S is greater than or equal to a predetermined threshold value (for example, 80%) for two focus detection directions among the three focus detection directions H, R, and L. judge. When the ratio of the contrast value S for the two directions is equal to or greater than the predetermined threshold, the control device 14 makes an affirmative determination in step S306 and proceeds to step S307. On the other hand, if the ratio of the contrast value S in only one direction is greater than or equal to the predetermined threshold value, or if the ratio of the contrast value S in all three directions is less than the predetermined threshold value, the control device 14 makes a negative determination in step S306 and performs step S308. Proceed to

  For the two directions in which the ratio of the contrast value S is equal to or greater than a predetermined threshold, it is assumed that there is little difference in detection accuracy regardless of which focus detection is performed. Therefore, in step S307, the control device 14 determines two directions in which the ratio of the contrast value S is equal to or greater than a predetermined threshold as the focus detection direction. Then, the control device 14 outputs the defocus amount obtained from the image shift amount in the two directions (the output corresponding to the two directions among the defocus amounts obtained from the output signal sequence corresponding to the microlens rows H1, R1, and L1). The average value of the defocus amount obtained from the signal sequence is determined as the defocus amount used for focus adjustment. Thereafter, the processing in FIG. 14 is terminated.

  On the other hand, in step S308, the control device 14 determines the direction in which the ratio of the contrast value S is the highest as the focus detection direction. Then, the control device 14 performs focus adjustment on the defocus amount obtained from the output signal sequence corresponding to the determined focus detection direction among the defocus amounts obtained from the output signal sequence corresponding to the microlens rows H1, R1, and L1. It is determined as the defocus amount used for. Thereafter, the processing in FIG. 14 is terminated.

According to the second embodiment described above, the following operational effects can be obtained.
(1) In the focus detection device of the present embodiment, the control device 14 determines the ratio of the second contrast value S (H2) to the first contrast value S (H1) and the fourth contrast to the third contrast value S (R1). When the ratio of the value S (R2) and the ratio of the sixth contrast value S (L2) to the fifth contrast value S (L1) are equal to or greater than a predetermined threshold, the horizontal direction H, the right diagonal direction R, and the left diagonal direction All of L are selected as the focus detection direction. Further, when all of the horizontal direction H, the right oblique direction R, and the left oblique direction L are selected as the focus detection directions, the control device 14 selects a first pair of signal rows (corresponding to the microlens row H1) and a third pair. The focus adjustment state of the photographic lens 20 is detected based on the signal sequence (corresponding to the microlens array R1) and the fifth pair of signal sequences (corresponding to the microlens array L1). Thereby, the focus adjustment state of the photographic lens 20 can be detected with high accuracy.

(Modification 1)
In the above-described embodiment, the defocus amount obtained from the output signal trains {a (i)} and {b (i)} corresponding to the microlens rows H1, R1, and L1 is used for focus adjustment of the photographing lens 20. An example was described. However, the defocus amount obtained from the output signal sequences {a (i)} and {b (i)} corresponding to the microlens rows H2, R2, and L2 may be used for the focus adjustment of the photographing lens 20. . Since the micro lenses ML are arranged at a half pitch in the micro lens rows H2, R2, and L2, according to the first modification, the focus adjustment is performed with higher accuracy when the edge of the subject exists perpendicular to the focus detection direction. be able to.

(Modification 2)
In the above-described embodiment, the defocus amount obtained from the output signal trains {a (i)} and {b (i)} corresponding to the microlens rows H1, R1, and L1 is used for focus adjustment of the photographing lens 20. An example was described. However, the defocus amounts for a plurality of rows of microlenses may be obtained, and the average value thereof may be used for focus adjustment of the photographing lens 20.

  For example, the case where the horizontal direction H is determined as the focus detection direction in the focus detection direction determination process will be described. As shown in FIG. 15, the control device 14 in this case includes a plurality of microlenses ML arranged in the horizontal direction H, and a plurality of (for example, three) microlens rows Hx, Hy, and Hz adjacent to each other. The defocus amount is obtained from the output signal sequences {a (i)} and {b (i)} of the corresponding pair of photoelectric conversion element arrays. Then, the control device 14 determines an average value of the defocus amounts corresponding to the micro lens rows Hx, Hy, Hz as the defocus amount used for the focus adjustment.

(Modification 3)
In the above-described embodiment, the example in which the focus detection direction is selected from the three directions of the horizontal direction H, the right diagonal direction R, and the left diagonal direction H has been described. However, the number of options for the focus detection direction is not limited thereto. It's okay. For example, as shown in FIG. 16, in the above three directions, the direction RX further rotated 30 degrees counterclockwise from the vertical direction V and the horizontal direction H, and the direction LX rotated 30 degrees clockwise from the horizontal direction H. The focus detection direction may be selected from the six directions including the direction.

(Modification 4)
In the above-described embodiment, the example using the focus detection sensor 12 in which the microlenses ML are arranged so as to be shifted by a half pitch for each row has been described. However, as shown in FIG. 17, the focal points in which the microlenses ML are arranged in a square arrangement. A detection sensor may be used.

  In this case, the control device 14 selects a focus detection direction from, for example, two directions of the horizontal direction H and the vertical direction V. Specifically, as shown in FIG. 17A, the control device 14 has a pair of photoelectric conversion element arrays corresponding to the microlens array H1 aligned in the horizontal direction H and the microlens array V1 aligned in the vertical direction V, respectively. The contrast value is obtained using {a (i)} and {b (i)}. Further, as shown in FIG. 17B, the control device 14 has a pair of photoelectric conversions corresponding to the microlens rows H2 arranged in a zigzag manner in the horizontal direction H and the microlens rows V2 arranged in a zigzag manner in the vertical direction V, respectively. The contrast value is obtained using the output signal sequence {a (i)} and {b (i)} of the element sequence. The control device 14 determines the focus detection direction based on these contrast values in the same manner as in the above-described embodiment.

(Modification 5)
In the above-described embodiment, the example in which S obtained by the equation (5), that is, the slope of the correlation amount C (k) near the minimum value of the correlation amount C (k) is used as the contrast value has been described. However, other values may be used as long as the values are proportional to the contrast. For example, an average value of the correlation amount C (k) may be used as the contrast value.

(Modification 6)
In the above-described embodiment, the example in which the focus detection direction is selected based on the ratio of the contrast value S of the microlens rows H2, R2, and L2 to the contrast value S of the microlens rows H1, R1, and L1 has been described. However, the focus detection direction may be selected based on the difference between the contrast value S of the microlens rows H1, R1, and L1 and the contrast value S of the microlens rows H2, R2, and L2. In this case, the direction with the smallest difference in contrast value S may be selected as the focus detection direction.

(Modification 7)
In the focus detection direction determination process of the second embodiment described above, the predetermined threshold used in the determinations in steps S304 and S306 may be changed according to the level of the contrast value S. For example, when the contrast value S is generally high, the predetermined threshold value may be set higher, and when the contrast value S is generally low, the predetermined threshold value may be set lower.

(Modification 8)
The present invention may be applied to a single-lens reflex digital camera. In this case, the focus detection sensor 12 may be arranged so that the subject light transmitted through the main mirror is guided to the focus detection sensor 12 by the sub mirror when the mirror is down.

  The above description is merely an example, and is not limited to the configuration of the above embodiment. Moreover, you may combine the structure of each modification suitably with the said embodiment.

DESCRIPTION OF SYMBOLS 1 ... Camera body, 2 ... Lens barrel, 10 ... Half mirror, 11 ... Imaging element, 12 ... Focus detection sensor, 14 ... Control apparatus, 20 ... Shooting lens, 21 ... Lens drive part, ML ... Micro lens, PD ... Photoelectric conversion element group

Claims (10)

A plurality of microlenses arranged two-dimensionally;
A first pair of photoelectric conversion units arranged in a first direction so as to receive a first pair of light beams that have passed through the first pair of regions of the pupil of the imaging optical system via the microlens; A second pair of photoelectric conversion units arranged side by side in a second direction so as to receive a second pair of light beams that have passed through the second pair of regions of the pupil via a microlens, and the microlens A plurality of photoelectric conversion means provided corresponding to each of
First acquisition means for acquiring a first pair of signal sequences from the photoelectric conversion means corresponding to the plurality of microlenses arranged in the first direction;
Second acquisition means for acquiring a second pair of signal sequences from the photoelectric conversion means corresponding to the plurality of microlenses arranged zigzag in the first direction;
Third acquisition means for acquiring a third pair of signal sequences from the photoelectric conversion means corresponding to the plurality of microlenses arranged in the second direction;
Fourth acquisition means for acquiring a fourth pair of signal sequences from the photoelectric conversion means corresponding to the plurality of microlenses arranged zigzag in the second direction;
Based on the relationship between the first pair and the second pair of signal sequences and the relationship between the third pair and the fourth pair of signal sequences, focus detection is performed in either the first direction or the second direction. Selection means for selecting as direction,
When the first direction is selected by the selection unit, a focus adjustment state of the imaging optical system is detected based on the first pair or the second pair of signal sequences, and the selection unit detects the first direction. When two directions are selected, focus detection means for detecting a focus adjustment state of the imaging optical system based on the third pair or the fourth pair of signal sequences;
A focus detection apparatus comprising: The focus detection apparatus according to claim 1,
First contrast calculating means for calculating a first contrast value from the first pair of signal sequences;
Second contrast calculating means for calculating a second contrast value from the second pair of signal sequences;
Third contrast calculating means for calculating a third contrast value from the third pair of signal sequences;
Fourth contrast calculating means for calculating a fourth contrast value from the fourth pair of signal sequences;
Further comprising
The selecting means is configured to determine the first direction and the second direction based on the relationship between the magnitudes of the first contrast value and the second contrast value and the magnitude relationship between the third contrast value and the fourth contrast value. One of the second directions is selected as a focus detection direction. The focus detection apparatus according to claim 2,
The selection means selects the first direction as a focus detection direction when a ratio of the second contrast value to the first contrast value is larger than a ratio of the fourth contrast value to the third contrast value; The focus is characterized in that the second direction is selected as the focus detection direction when the ratio of the fourth contrast value to the third contrast value is larger than the ratio of the second contrast value to the first contrast value. Detection device. The focus detection apparatus according to claim 3,
The selection means is configured to detect the first direction when both the ratio of the second contrast value to the first contrast value and the ratio of the fourth contrast value to the third contrast value are equal to or greater than a predetermined threshold. And both the second direction as the focus detection direction,
The focus detection means, when both the first direction and the second direction are selected as the focus detection directions by the selection means, the signal sequence of the first pair or the second pair, and the third A focus detection apparatus that detects a focus adjustment state of the imaging optical system based on a pair or the fourth pair of signal sequences. In the focus detection apparatus according to any one of claims 1 to 4,
The focus detection unit detects a focus adjustment state of the imaging optical system based on the first pair of signal sequences when the selection unit selects the first direction, and the selection unit detects the focus adjustment state. When the second direction is selected, the focus detection apparatus detects a focus adjustment state of the imaging optical system based on the third pair of signal sequences. In the focus detection apparatus according to any one of claims 1 to 5,
Fifth acquisition means for acquiring a fifth pair of signal sequences from the photoelectric conversion means corresponding to the plurality of microlenses arranged in a third direction;
Sixth acquisition means for acquiring a sixth pair of signal sequences from the photoelectric conversion means corresponding to the plurality of microlenses arranged zigzag in the third direction;
Further comprising
The photoelectric conversion means has a third pair of photoelectric conversion units arranged side by side in the third direction so as to receive a third pair of light beams that have passed through the third pair of regions of the pupil via the microlens. Further comprising
The selection means includes: a relationship between the first pair and the second pair of signal sequences; a relationship between the third pair and the fourth pair of signal sequences; and the fifth pair and the sixth pair of signal sequences. Based on the relationship, select one of the first direction, the second direction, and the third direction as a focus detection direction,
The focus detection unit detects a focus adjustment state of the imaging optical system based on the first pair or the second pair of signal sequences when the first direction is selected by the selection unit; When the second direction is selected by the selection unit, a focus adjustment state of the imaging optical system is detected based on the third pair or the fourth pair of signal sequences, and the selection unit detects the first direction. When three directions are selected, the focus detection apparatus detects a focus adjustment state of the imaging optical system based on the fifth pair or the sixth pair of signal strings. The focus detection apparatus according to claim 6,
The plurality of microlenses are arranged with a half-pitch shift for each row,
The focus detection apparatus according to claim 1, wherein the first direction, the second direction, and the third direction are directions separated from each other by approximately 60 degrees. The focus detection apparatus according to claim 7,
The focus detection apparatus, wherein the plurality of microlenses have a honeycomb structure. The focus detection apparatus according to any one of claims 1 to 8,
Focus adjusting means for adjusting the focus of the imaging optical system based on the focus adjustment state detected by the focus detection device;
An imaging apparatus comprising: The imaging device according to claim 9,
Splitting means for splitting the light beam from the imaging optical system into two;
An image sensor on which one of the two light beams split by the splitting unit is incident;
Further comprising
The imaging apparatus, wherein the other light beam of the two light beams is incident on the focus detection device.

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