JP2011033975A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain data in a cross pixel position where two focus-detecting pixel arrays cross each other, regarding data array of each of two focus-detecting pixel arrays on an imaging device using a pupil phase difference detection system. <P>SOLUTION: When a first focus-detecting pixel is arranged in the cross pixel position where the first focus-detecting pixel array and the second focus-detecting pixel array cross each other, among data arrays α14, α24 to α84 of the first focus-detecting pixel array, data α44 of the first focus-detecting pixel array in the cross pixel position is obtained as its own data of the first focus-detecting pixel in the cross pixel position. Among data arrays β41, β42 to β48 of the second focus-detecting pixel array, data β44 of the second focus-detecting pixel array in the cross pixel position is obtained based on the data α44 in the cross pixel position and data α34, α54, β43 and β45 in the pixel positions adjacent to the cross pixel position. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an imaging apparatus.

  2. Description of the Related Art An imaging device including an imaging element in which an imaging pixel and a pupil division type focus detection pixel are mounted is known (see, for example, Patent Document 1). In such an imaging apparatus, pupil-divided focus detection pixels are arranged in a straight line, and the focus adjustment state of an image formed in the focus detection pixel array is detected based on the output of the focus detection pixel array.

JP 2008-224801 A

  However, in the conventional imaging device described above, the focus adjustment state cannot be detected when there is no change in the contrast of the image in the direction of the focus detection pixel array. In order to avoid such a problem, it is conceivable that the focus detection pixels arranged in a plurality of directions are arranged so as to intersect with each other, but any one focus is provided at a pixel position where the plurality of focus detection pixel arrays intersect. Only focus detection pixels belonging to the detection pixel array can be arranged. For this reason, in the detection of the focus adjustment state using the other focus detection pixel arrays, there is a drawback in that the output of the focus detection pixel at the intersection pixel position is lost and the detection accuracy of the focus adjustment state is lowered.

  The imaging apparatus according to claim 1 is a two-dimensional array of a plurality of imaging pixels each outputting an imaging signal relating to a subject image and a plurality of focus detection pixels each outputting a focus detection signal relating to a divided pupil image. An image sensor that is arranged in such a manner that a plurality of focus detection pixel arrays formed by arranging a plurality of focus detection pixels adjacent to each other and arranged in a plurality of linear rows intersect at a predetermined pixel position; Based on the focus detection signal output by at least one of the plurality of focus detection pixels arranged in the vicinity of the predetermined pixel position and the focus detection signal at the predetermined pixel position, the plurality of focus detection pixel arrays Focus detection signal acquisition means for acquiring specific focus detection signal data at the predetermined pixel position included in the corresponding focus detection signal data array, and focus detection signal data Based on the sequence, the split-pupil phase detection method, which comprising: a focus detection means for detecting a focusing state of a subject image.

  According to the present invention, the above-described drawbacks can be overcome and the focus adjustment state can be detected with high accuracy in a plurality of directions.

It is a cross-sectional view showing the configuration of the digital still camera of one embodiment. It is a figure which shows the focus detection position on the imaging | photography screen of an interchangeable lens. It is a front view which shows the detailed structure of an image pick-up element. It is a figure which shows the shape of the micro lens of an imaging pixel and a focus detection pixel. It is a front view of an imaging pixel. It is a front view of a focus detection pixel. It is sectional drawing of an imaging pixel. It is sectional drawing of a focus detection pixel. It is a figure for demonstrating the mode of the imaging light beam which an imaging pixel receives. It is a figure for demonstrating the mode of the imaging light beam which a focus detection pixel receives. It is a flowchart which shows the imaging operation of a digital still camera. It is a figure which shows the relationship of the correlation amount C (k) with respect to the shift amount k of a pair of data. It is the figure which showed the area | region of 8 pixels x 8 pixels centering on the pixel position where a 1st focus detection pixel arrangement | sequence and a 2nd focus detection pixel arrangement | sequence cross | intersect. It is a front view which shows the detailed structure of an image pick-up element. It is the figure which showed the area | region of 8 pixels x 8 pixels centering on the pixel position where a 1st focus detection pixel arrangement | sequence and a 2nd focus detection pixel arrangement | sequence cross | intersect. It is a front view which shows the detailed structure of an image pick-up element. It is a front view of a focus detection pixel. It is sectional drawing of a focus detection pixel. It is the figure which showed the area | region of 8 pixels x 8 pixels centering on the pixel position where a 1st focus detection pixel arrangement | sequence and a 2nd focus detection pixel arrangement | sequence cross | intersect. It is a front view which shows the detailed structure of an image pick-up element. It is the figure which showed the area | region of 8 pixels x 8 pixels centering on the pixel position where a 1st focus detection pixel arrangement | sequence and a 2nd focus detection pixel arrangement | sequence cross | intersect. It is a figure which shows the focus detection position on the imaging | photography screen of an interchangeable lens. It is a front view which shows the detailed structure of an image pick-up element. It is a front view of a focus detection pixel. It is the figure which showed the area | region of 8 pixels x 8 pixels centering on the pixel position where a 1st focus detection pixel arrangement | sequence and a 2nd focus detection pixel arrangement | sequence cross | intersect. It is a front view which shows the detailed structure of an image pick-up element. It is a front view which shows the detailed structure of an image pick-up element. It is a front view of a focus detection pixel and an imaging pixel.

  As an imaging apparatus according to an embodiment, an interchangeable lens digital still camera will be described as an example. FIG. 1 is a cross-sectional view showing the configuration of the digital still camera of the present embodiment. A digital still camera 201 according to the present embodiment includes an interchangeable lens 202 and a camera body 203, and the interchangeable lens 202 is attached to the camera body 203 via a mount unit 204. An interchangeable lens 202 having various photographing optical systems can be attached to the camera body 203 via a mount unit 204.

  The interchangeable lens 202 includes a lens 209, a zooming lens 208, a focusing lens 210, a diaphragm 211, a lens drive control device 206, and the like. The lens drive control device 206 includes a microcomputer (not shown), a memory, a drive control circuit, and the like. The lens drive control device 206 includes drive control for adjusting the focus of the focusing lens 210 and the aperture diameter of the aperture 211, zooming lens 208, and focusing. In addition to detecting the state of the lens 210 and the aperture 211, the transmission of lens information (described later) and the reception of camera information (defocus amount, aperture value, etc.) are performed through communication with a body drive control device 214 (described later). The aperture 211 forms an aperture having a variable aperture diameter at the center of the optical axis in order to adjust the amount of light and the amount of blur.

  The camera body 203 includes an imaging element 212, a body drive control device 214, a liquid crystal display element drive circuit 215, a liquid crystal display element 216, an eyepiece lens 217, a memory card 219, and the like. In the imaging element 212, imaging pixels are two-dimensionally arranged, and focus detection pixels are incorporated in portions corresponding to focus detection positions (focus detection areas). Details of the image sensor 212 will be described later.

  The body drive control device 214 includes a microcomputer, a memory, a drive control circuit, and the like, and controls the drive of the image sensor 212, reads out the image signal and the focus detection signal, performs the focus detection calculation based on the focus detection signal, and the focus of the interchangeable lens 202. The adjustment is repeated, and image signal processing and recording, operation control of the digital still camera 201 and the like are performed. The body drive control device 214 communicates with the lens drive control device 206 through the electrical contact 213 to receive lens information and transmit camera information.

  The liquid crystal display element 216 functions as an electric view finder (EVF). The liquid crystal display element driving circuit 215 displays a through image by the imaging element 212 on the liquid crystal display element 216, and the photographer can observe the through image through the eyepiece lens 217. The memory card 219 is an image storage that stores an image captured by the image sensor 212.

  A subject image is formed on the light receiving surface of the image sensor 212 by the light beam that has passed through the interchangeable lens 202. This subject image is photoelectrically converted by the image sensor 212, and an image signal and a focus detection signal are sent to the body drive control device 214.

  The body drive control device 214 calculates a defocus amount based on the focus detection signal from the focus detection pixel of the image sensor 212 and sends the defocus amount to the lens drive control device 206. The body drive control device 214 processes the image signal from the image sensor 212 to generate image data, stores the image data in the memory card 219, and transmits the through image signal from the image sensor 212 to the liquid crystal display element drive circuit 215. The through image is displayed on the liquid crystal display element 216. Further, the body drive control device 214 sends aperture control information to the lens drive control device 206 to control the aperture of the aperture 211.

  The lens drive controller 206 updates the lens information according to the focusing state, zooming state, aperture setting state, aperture opening F value, and the like. Specifically, the positions of the zooming lens 208 and the focusing lens 210 and the aperture value of the aperture 211 are detected, and lens information is calculated according to these lens positions and aperture values, or a lookup prepared in advance. Lens information corresponding to the lens position and aperture value is selected from the table.

  The lens drive control device 206 calculates a lens drive amount based on the received defocus amount, and drives the focusing lens 210 to the in-focus position according to the lens drive amount. Further, the lens drive control device 206 drives the diaphragm 211 in accordance with the received diaphragm value.

  FIG. 2 is a diagram showing a focus detection position (focus detection area) on the shooting screen of the interchangeable lens 202, and an image is sampled on the shooting screen when a focus detection pixel column on the image sensor 212 described later performs focus detection. An example of a region (focus detection area, focus detection position) to be performed is shown. In this example, cross-shaped focus detection areas 101 to 103 are arranged at the center (on the optical axis) on the rectangular shooting screen 100 and at three positions on the left and right. In the longitudinal direction of the focus detection area indicated by a rectangle, focus detection pixels are linearly arranged in the horizontal direction and the vertical direction.

  FIG. 3 is a front view showing a detailed configuration of the image sensor 212, and shows details of a pixel arrangement in which the vicinity of the focus detection area 102 in FIG. 2 is enlarged. Imaging pixels 310 are densely arranged on the imaging element 212 in a two-dimensional square lattice pattern. The imaging pixel 310 includes a red pixel (R), a green pixel (G), and a blue pixel (B), and is arranged according to a Bayer arrangement rule. For vertical focus detection, vertical focus detection focus detection pixels 313 and 314 having the same pixel size as the imaging pixel are alternately arranged, and the original green pixels and blue pixels should be continuously arranged in the vertical direction. Arranged continuously on a straight line. Similarly, for horizontal focus detection, horizontal focus detection focus detection pixels 315 and 316 having the same pixel size as the imaging pixel are alternately arranged, and the original green and red pixels should be continuously arranged in the horizontal direction. Are arranged on a straight line.

  At the pixel position where the horizontal focus detection pixel array intersects the vertical focus detection pixel array (the position where the green pixel should be arranged according to the Bayer array arrangement rule), the focus detection pixel 313 for vertical focus detection is provided. Be placed. The pixel arrangement in the focus detection areas 101 and 103 is basically the same as that shown in FIG.

  FIG. 4 is a diagram illustrating the shape of the microlens 10 of the imaging pixel and the focus detection pixel, which is a shape that is originally cut out from a circular microlens 9 larger than the pixel size in a square shape corresponding to the pixel size, The cross section in the direction of the diagonal line passing through the optical axis of the microlens 10 and the cross section in the direction of the horizontal line passing through the optical axis of the microlens 10 have shapes shown in FIGS.

  As shown in FIG. 5, the imaging pixel 310 includes a rectangular microlens 10, a photoelectric conversion unit 11 whose light receiving area is limited to a square by a light shielding mask described later, and a color filter (not shown). There are three types of color filters, red (R), green (G), and blue (B), and each has a spectral sensitivity characteristic. In the image pickup device 212, image pickup pixels 310 having respective color filters are arranged in a Bayer array.

  The focus detection pixels 313, 314, 315, and 316 are provided with white filters that transmit all visible light in order to perform focus detection for all colors. The white filters include green pixels, red pixels, It has a spectral sensitivity characteristic that is the sum of the spectral sensitivity characteristics of blue pixels. In other words, the light wavelength region in which the focus detection pixels 313, 314, 315, and 316 exhibit high spectral sensitivity includes the light wavelength region in which the green pixel, red pixel, and blue pixel exhibit high spectral sensitivity.

  As shown in FIG. 6A showing a front view, the focus detection pixel 313 has a light-receiving area that is an upper half of a square (a square is divided into two equal parts by a horizontal line) using a rectangular microlens 10 and a light-shielding mask described later. The photoelectric conversion unit 13 is limited to the upper half) and a white filter (not shown).

  Further, as shown in FIG. 6B showing a front view, the focus detection pixel 314 has a light receiving area divided into a lower half of a square (a square is divided into two equal parts by a horizontal line) using a rectangular microlens 10 and a light shielding mask described later. The photoelectric conversion unit 14 is limited to the lower half of the case, and a white filter (not shown).

  When the front view of the focus detection pixel 313 and the front view of the focus detection pixel 314 are displayed so as to overlap each other with the microlens 10 as a reference, the photoelectric conversion units 13 and 14 whose light receiving areas are limited by the light shielding mask are arranged in the vertical direction. Yes. In FIGS. 6A and 6B, when the remaining portion (broken line portion) obtained by halving the square is added to the light receiving region portion obtained by halving the square, a square having the same size as the light receiving region of the imaging pixel is obtained. .

  As shown in FIG. 6C, which shows a front view, the focus detection pixel 315 has a rectangular half-lens 10 and a light-shielding mask, which will be described later. The left half of the photoelectric conversion unit 15 and a white filter (not shown).

  Further, as shown in FIG. 6D showing a front view, the focus detection pixel 316 divides the light receiving region into a right half of a square (a square is divided into two equal parts by a vertical line) using a rectangular microlens 10 and a light shielding mask described later. The photoelectric conversion unit 16 limited to the right half) and a white filter (not shown).

  When the front view of the focus detection pixel 315 and the front view of the focus detection pixel 316 are displayed so as to overlap each other with the microlens 10 as a reference, the photoelectric conversion units 15 and 16 in which the light receiving area is limited by the light shielding mask are arranged in the horizontal direction. Yes. In FIGS. 6C and 6D, when the remaining portion (broken line portion) obtained by halving the square is added to the light receiving region portion obtained by halving the square, a square having the same size as the light receiving region of the imaging pixel is obtained. .

  FIG. 7 is a cross-sectional view of the imaging pixel 310 when a cross section of the imaging pixel array is taken along a straight line in the vertical direction. In the imaging pixel 310, a light shielding mask 30 is formed in proximity to the imaging photoelectric conversion unit 11, and the photoelectric conversion unit 11 receives light that has passed through the opening 30 a of the light shielding mask 30. A planarizing layer 31 is formed on the light shielding mask 30, and a color filter 38 is formed thereon. A planarizing layer 32 is formed on the color filter 38, and the microlens 10 is formed thereon. The shape of the opening 30 a is projected forward by the microlens 10. The photoelectric conversion unit 11 is formed on the semiconductor circuit substrate 29.

  FIG. 8 is a cross-sectional view of the focus detection pixels 313 and 314 when a cross section of the focus detection pixel array including the focus detection pixels 313 and 314 is taken along a vertical straight line. In the focus detection pixels 313 and 314, a light shielding mask 30 is formed in proximity to the focus detection photoelectric conversion units 13 and 14, and the light beam conversion units 13 and 14 have passed through the openings 30 b and 30 c of the light shielding mask 30. Receives light. A planarizing layer 31 is formed on the light shielding mask 30, and a white filter 39 is formed thereon. A planarizing layer 32 is formed on the white filter 39, and the microlens 10 is formed thereon. The shapes of the openings 30b and 30c are projected forward by the microlens 10. The photoelectric conversion units 13 and 14 are formed on the semiconductor circuit substrate 29. The structure of the focus detection pixels 315 and 316 is merely the same as the structure of the focus detection pixel shown in FIG. 8 except that the structure of the focus detection pixels 313 and 314 is rotated by 90 degrees.

  FIG. 9 is a diagram for explaining the state of the imaging light beam received by the imaging pixel 310 shown in FIGS. 3 and 7, and takes a cross section of the imaging pixel array with a straight line in the vertical direction. The photoelectric conversion units 11 of all the imaging pixels arranged on the imaging element receive the light flux that has passed through the light shielding mask opening 30a disposed in the vicinity of the photoelectric conversion unit 11. The shape of the light-shielding mask opening 30a is projected by the microlens 10 of each imaging pixel onto a region 95 common to all imaging pixels on the exit pupil 90 that is separated from the microlens 10 by the distance measuring pupil distance d.

  Therefore, the photoelectric conversion unit 11 of each imaging pixel receives the light beam 71 that passes through the region 95 and the microlens 10 of each imaging pixel, and passes through the region 95 to the microlens 10 of each imaging pixel, and the microbeams 71 pass through each micropixel 10. A signal corresponding to the intensity of the image formed on the lens 10 is output.

  FIG. 10 is a diagram for explaining the state of the focus detection light beam received by the focus detection pixels 313 and 314 shown in FIGS. 3 and 8 in comparison with FIG. 9, and the focus detection pixel array is represented by a straight line in the vertical direction. The cross section is taken.

  The photoelectric conversion units 13 and 14 of all the focus detection pixels arranged on the image sensor receive the light flux that has passed through the light shielding mask openings 30b and 30c disposed in proximity to the photoelectric conversion units 13 and 14. The shape of the light-shielding mask opening 30b is projected by the microlens 10 of each focus detection pixel 313 onto an area 93 that is common to all focus detection pixels 313 on the exit pupil 90 that are separated from the microlens 10 by the distance measurement pupil distance d. The Similarly, the shape of the light-shielding mask opening 30c is an area 94 common to all the focus detection pixels 314 on the exit pupil 90 separated from the microlens 10 by the distance measurement pupil distance d by the microlens 10 of each focus detection pixel 314. Projected. The pair of areas 93 and 94 is called a distance measuring pupil.

  Accordingly, the photoelectric conversion unit 13 of each focus detection pixel 313 receives the light beam 73 passing through the distance measuring pupil 93 and the micro lens 10 of each imaging pixel, and passes through the distance measuring pupil 93 to the micro lens 10 of each imaging pixel. A signal corresponding to the intensity of the image formed on each microlens 10 is output by the light beam 73 directed. The photoelectric conversion unit 14 of each focus detection pixel 314 receives the light beam 74 passing through the distance measuring pupil 94 and the micro lens 10 of each imaging pixel, and passes through the distance measuring pupil 94 to the micro lens 10 of each imaging pixel. A signal corresponding to the intensity of the image formed on each microlens 10 is output by the light beam 74 directed.

  A region where the distance measuring pupils 93 and 94 on the exit pupil 90 through which the light beams 73 and 74 received by the pair of focus detection pixels 313 and 314 pass is integrated on the exit pupil 90 through which the light beam 71 received by the imaging pixel 310 passes. The light fluxes 73 and 74 are complementary to the light flux 71 on the exit pupil 90.

  A large number of the pair of focus detection pixels 313 and 314 described above are arranged alternately and linearly, and the output of the photoelectric conversion unit of each focus detection pixel is collected into a pair of output groups corresponding to the distance measurement pupil 93 and the distance measurement pupil 94. Thus, information on the intensity distribution of the pair of images formed on the focus detection pixel array (vertical direction) by the pair of light beams passing through the distance measuring pupil 93 and the distance measuring pupil 94 can be obtained. By applying an image shift detection calculation process (correlation calculation process, phase difference detection process), which will be described later, to this information, an image shift amount of a pair of images is detected by a so-called pupil division type phase difference detection method. Furthermore, by performing a conversion operation according to the proportional relationship between the distance between the center of gravity of the pair of distance measurement pupils and the distance measurement pupil distance, the deviation between the planned image formation surface and the image formation surface at the focus detection position (vertical direction) is performed. (Defocus amount) is calculated.

  The focus detection light beams received by the focus detection pixels 315 and 316 are merely the same as the light beams shown in FIG. 10 except that the pair of focus detection light beams 73 and 74 received by the focus detection pixels 313 and 314 are rotated by 90 degrees. A pair of distance measurement pupils obtained by rotating the distance measurement pupils 93 and 94 by 90 degrees are set. A large number of pairs of focus detection pixels 315 and 316 are arranged alternately and in a straight line, and the output of the photoelectric conversion unit of each focus detection pixel is collected into a pair of output groups corresponding to the pair of distance measurement pupils. Information on the intensity distribution of the pair of images formed on the focus detection pixel array (horizontal direction) by the pair of light beams respectively passing through the distance pupil is obtained. Based on this information, the deviation (defocus amount) between the planned imaging plane and the imaging plane at the focus detection position (horizontal direction) is calculated.

  FIG. 11 is a flowchart showing the imaging operation of the digital still camera 201. When the power of the digital still camera 201 is turned on in step S100, the body drive control device 214 starts an imaging operation after step S110. In step S110, all pixel data is read from the image sensor 310. In subsequent step S120, data obtained by thinning out the data of the imaging pixels is displayed on the electronic viewfinder. In step S130, based on the first focus detection pixels (focus detection pixels 313 and 314 arranged in the vertical direction) in the selected focus detection area, the second focus detection pixels (focus detection arranged in the horizontal direction). Pixels 315 and 316) Interpolate the data of the virtual second focus detection pixel at the pixel position where the array intersects the first focus detection pixel array. Details will be described later. The focus detection area is assumed to be selected in advance by the photographer using one of the focus detection areas 101 to 103 using a focus detection area selection member (not shown).

  In step S135, an image shift detection calculation process (described later) is performed based on the pair of image data of the first focus detection pixel array and the pair of image data of the second focus detection pixel array including the virtual second focus detection pixel. Correlation calculation processing, phase difference detection processing) and defocus conversion calculation are performed to calculate the defocus amounts in the vertical and horizontal directions in the selected focus detection area. Further, the final defocus amount is calculated by averaging the defocus amounts in the two directions. If the reliability of the defocus amount in one direction is low or the defocus amount cannot be calculated, the defocus amount is not averaged and the other defocus amount is used. Further, when the reliability of the defocus amount is low in both directions, or when the defocus amount cannot be calculated, the focus cannot be detected.

  In step S140, it is checked whether or not the focus is close, that is, whether or not the calculated absolute value of the defocus amount is within a predetermined value. If it is determined that the lens is not in focus, the process proceeds to step S150, the defocus amount is transmitted to the lens drive controller 206, and the focusing lens 210 of the interchangeable lens 202 is driven to the focus position. Then, it returns to step S110 and repeats the operation | movement mentioned above.

  Even when focus detection is impossible, the process branches to this step, a scan drive command is transmitted to the lens drive control device 206, and the focusing lens 210 of the interchangeable lens 202 is driven to scan from infinity to the nearest. Then, it returns to step S110 and repeats the operation | movement mentioned above.

  If it is determined in step S140 that the focus is close, the process proceeds to step S160, and it is determined whether or not a shutter release has been performed by operating a shutter button (not shown). If it is determined that the shutter release has not been performed, the process returns to step S110 and the above-described operation is repeated. On the other hand, if it is determined that the shutter release has been performed, the process proceeds to step S170, where an aperture adjustment command is transmitted to the lens drive control unit 206, and the aperture value of the interchangeable lens 202 is set to the control F value (the F or the camera set automatically Value). When the aperture control is completed, the image sensor 212 is caused to perform an imaging operation, and image data is read from the imaging pixel 310 of the imaging element 212 and all the focus detection pixels 313, 314, 315, and 316.

  In step S180, the data of the virtual imaging pixels at the respective pixel positions in the focus detection pixel row are used as the data of the imaging pixels 310 around the focus detection pixels 313, 314, 315, and 316 and the focus detection pixels 313, 314, 315, and 316. Pixel interpolation is performed based on the data. This interpolation process will be described later. In the subsequent step S190, image data composed of the data of the imaging pixel 310 and the data of the interpolated imaging pixel 310 is stored in the memory card 219, and the process returns to step S110 to repeat the above-described operation.

  Details of the image shift detection calculation process (correlation calculation process, phase difference detection process) in step S135 of FIG. 11 will be described below. For the sake of simplicity, the processing for one of the two focus detection pixel arrays (the first focus detection pixel array and the second focus detection pixel array) will be described, but the process for the other is also the same.

In the pair of images detected by the focus detection pixels 313 and 314 or the focus detection pixels 315 and 316, there is a possibility that the distance measurement pupil is vignetted by the aperture of the lens and the light amount balance is lost. Is subjected to a correlation calculation capable of maintaining the image shift detection accuracy.
For a pair of data strings (A1 _{1 to} A1 _M , A2 _{1 to} A2 _M : M is the number of data) read out from the focus detection pixel string, a correlation calculation formula (1) disclosed in Japanese Patent Laid-Open No. 2007-333720 ) To calculate the correlation amount C (k).
C (k) = Σ | A1 n × A2 n + 1 + k -A2 n + k × A1 n + 1 | (1)

In equation (1), the Σ operation is accumulated for n, but the range taken by n is limited to a range in which data of A1 _n , A1 _{n + 1} , A2 _{n + k} , A2 _{n + 1 + k} exists according to the image shift amount k. . The image shift amount k is an integer and is a relative shift amount with the data interval of the data string as a unit.

As shown in FIG. 12A, the calculation result of the expression (1) indicates that the correlation amount C (k) is obtained when the pair of data has a high correlation amount (k = k _j = 2 in FIG. 12A). Minimal (the smaller the value, the higher the degree of correlation). The shift amount k _s that gives the minimum value C (k _s ) with respect to the continuous correlation amount is obtained using the three-point interpolation method according to the equations (2) to (5).
k _s = k _j + D / SLOP (2)
C (k _s ) = C (k _j ) − | D | (3)
D = {C (k _j −1) −C (k _j +1)} / 2 (4)
SLOP = MAX {C ( _kj + 1) -C ( _kj ), C ( _kj- 1) -C ( _kj )}
(5)

Whether or not the shift amount k _s calculated by Expression (2) is reliable is determined as follows. As shown in FIG. 12B, when the degree of correlation between a pair of data is low, the value of the interpolated correlation minimum value C (k _s ) increases. Therefore, when C (k _s ) is equal to or greater than a predetermined threshold value, it is determined that the reliability of the calculated shift amount is low, and the calculated shift amount ks is canceled.

Alternatively, in order to normalize C (k _s ) with the contrast of data, when the value obtained by dividing C (k _s ) by SLOP that is proportional to the contrast is equal to or greater than a predetermined value, the calculated shift amount It is determined that the reliability is low, and the calculated shift amount ks is canceled. Alternatively, when SLOP that is a value proportional to the contrast is equal to or smaller than a predetermined value, it is determined that the subject has low contrast and the reliability of the calculated shift amount is low, and the calculated shift amount k _s is canceled. .

Figure 12 (c), the low level of correlation between the pair of data when there is no drop in correlation quantity C (k) is between the shift amount in the range _k min _{to k max,} the minimum value C _{(k s} In such a case, it is determined that the focus cannot be detected.

If it is determined that the calculated shift amount k _s is reliable, it is converted into the image shift amount shft by Equation (6).
shft = PY × k _s (6)

In Expression (6), PY is twice the pixel pitch (detection pitch) of the focus detection pixels 313 and 314 or the focus detection pixels 315 and 316. The image shift amount calculated by Expression (6) is multiplied by a predetermined conversion coefficient _Kd , and converted to a defocus amount def as represented by Expression (7). The conversion coefficient _Kd is a value obtained by dividing the distance-measuring pupil distance d by the center-of-gravity interval between the pair of distance-measuring pupils.
def = K _d × shft (7)

  Details of the focus detection pixel interpolation process in step S130 of FIG. 11 will be described below. FIG. 13 is a diagram showing an area of 8 pixels × 8 pixels centering on a pixel position where the first focus detection pixel array and the second focus detection pixel array intersect. The data of the first focus detection pixel array is indicated by α14, α24,..., Α84 as shown in FIG. 13, and the data of the second focus detection pixel array is indicated by β41, β42,. ing. Since the first focus detection pixel is disposed at the intersecting pixel position (that is, the second focus detection pixel is not disposed), the second focus detection pixel 316 is virtually disposed at the pixel position. In this case, the data is β44.

  As described above, the light beam obtained by adding the focus detection light beam 73 received by the first focus detection pixel 313 and the focus detection light beam 74 received by the first focus detection pixel 314 is received by the second focus detection pixel 315. The focus detection light beam and the focus detection light beam received by the second focus detection pixel 316 are equal to each other.

Therefore, in the case where it is assumed that the data generated by the focus detection light beam 73 received by the first focus detection pixel 313 at the intersection pixel position and the first focus detection pixel 314 is virtually arranged at the intersection pixel position. The data γ obtained by adding the data generated by the focus detection light beam 74 received by the first focus detection pixel 314 is based on the data of the first focus detection pixel in the vicinity of the intersection pixel position and the following equation: Is calculated.
γ = α44 + (α34 + α54) / 2 (8)

On the other hand, the data δ generated by the light beam received by the second focus detection pixel 315 at the intersection pixel position is calculated as the following equation by averaging the data of the second focus detection pixels 315 sandwiching the intersection pixel position. Is done.
δ = (β43 + β45) / 2 (9)

As described above, the data β44 when the second focus detection pixel 316 is virtually arranged at the intersection pixel position is obtained as follows.
β44 = γ−δ = α44 + (α34 + α54) / 2− (β43 + β45) / 2
(10)

  Since the data β44 obtained by the equation (10) is obtained by using the data of the intersection pixel position and the data of the pixel adjacent to the intersection pixel position, the data of the focus detection pixel 316 near the intersection pixel position is obtained. When calculated simply by averaging, for example, the interpolation accuracy is remarkably improved as compared with the case where β44 = (β42 + β46) / 2, for example, and the calculation accuracy of focus detection using the interpolation data is also improved.

Details of the imaging pixel interpolation processing in step S180 of FIG. 11 will be described below. In FIG. 13, when the imaging pixels are arranged according to the arrangement rule of the Bayer array, green pixels are arranged at the intersection pixel positions. If the data when the green pixel is virtually arranged at the crossing pixel position is G44, the data G44 can be obtained by averaging the four green pixel data G33, G35, G53, and G55 that are closest to the crossing pixel position. it can.
G44 = (G33 + G35 + G53 + G55) / 4 (11)

Data when a green pixel is virtually arranged on the focus detection pixel array other than the intersecting pixel position according to the arrangement rule of the Bayer array can also be obtained by averaging the data of the four adjacent green pixels. . In addition, the data when virtual red pixels and blue pixels are virtually arranged on the focus detection pixel array other than the intersecting pixel position according to the arrangement rule of the Bayer array is basically closest to the pixel position of the virtual pixel 2. The data of two red pixels or blue pixels is averaged. For example, assuming that the data when a blue pixel is virtually arranged at the pixel position below the intersecting pixel position is B54, B54 is obtained by the following equation.
B54 = (B52 + B56) / 2 (12)

If there are blue pixels closest to the diagonal, they may be used for averaging. For example, assuming that the data when a blue pixel is virtually arranged at the pixel position below the intersecting pixel position is B54, B54 is obtained by the following equation.
B54 = (B52 + B56 + B32 + B36 + B72 + B76) / 6 (13)

Further, for example, assuming that the data when a red pixel is virtually arranged at the pixel position right next to the intersecting pixel position is R45, R45 is obtained by the following equation.
R45 = (R25 + R65) / 2 (14)

If there are red pixels closest to the diagonal, they may be used for averaging. For example, assuming that the data when a red pixel is virtually arranged at the pixel position right next to the intersecting pixel position is R45, R45 is obtained by the following equation.
R45 = (R25 + R65 + R23 + R63 + R27 + R67) / 6 (15)

In the imaging pixel interpolation process, data of imaging pixels of the same color adjacent to the virtual imaging pixel is used, but data of focus detection pixels may be further used. For example, if the data when a virtual blue pixel is virtually arranged at the pixel position below the intersecting pixel position is B54, assuming that the hue does not change greatly in the vicinity of the pixel position, the focus detection pixel The luminance data (α54 + (α44 + α64) / 2) obtained based on the data and the blue / white component ratio ((B52 + B56) / (B52 + B56 + G53 + G55 + R63 + R65)) obtained based on the data of the neighboring imaging pixels. By multiplying, data B54 can be obtained as follows.
B54 = (α54 + (α44 + α64) / 2) × (B52 + B56) / (B52 + B56 + G53 + G55 + R63 + R65) (16)

  As described above, by using the pixel position of the virtual imaging pixel and the data of the focus detection pixel in the vicinity thereof, the imaging pixel interpolation accuracy for an image having a high-frequency spatial frequency component can be improved.

  In the case where a plurality of focus detection pixel arrays intersect as in the above embodiment, the focus detection pixel data at the intersecting pixel position can be interpolated with high accuracy, so that focus detection is accurately performed in a plurality of directions. It becomes possible.

  In addition, the imaging pixels are arranged according to the arrangement rule of the Bayer arrangement, and the intersection pixel positions of the plurality of focus detection pixel arrays are set as the pixel positions where the green pixels are to be arranged. In the case of interpolation, it becomes possible to perform interpolation with high accuracy.

  When performing pupil-division focus detection in a focus detection area away from the screen center (imaging optical axis), the alignment direction of the pair of focus detection light beams is perpendicular to the straight line connecting the focus detection area and the screen center. Arrangement is more advantageous because when the exit pupil position of the interchangeable lens changes, an imbalance of vignetting between the pair of focus detection light beams is less likely to occur. In the above-described embodiment, in the focus detection areas 102 and 103 separated from the screen center (imaging optical axis), the intersecting pixel positions are arranged in a direction orthogonal to the straight line connecting the focus detection area and the screen center (a direction in which the angle is large). By disposing the focus detection pixels 313 belonging to the first focus detection pixel array, it is possible to prevent the focus detection light beam from being unbalanced in the focus detection area having a high image height and to perform focus detection reliably.

<< Other Embodiments of the Invention >>
<A third focus detection pixel is arranged at the intersection pixel position>
FIG. 14 is a front view illustrating a detailed configuration of the image sensor 212 according to another embodiment, and corresponds to FIG. 3. 3 is different from FIG. 3 in that the pixel position (Bayer array arrangement) where the vertical focus detection pixel array (first focus detection pixel array) and the horizontal focus detection pixel array (second focus detection pixel array) intersect. The point is that a focus detection pixel 317 (third focus detection pixel) different from the first focus detection pixel and the second focus detection pixel is arranged at a pixel position where a green pixel is to be arranged by rule.

  The focus detection pixel 317 has the same structure as the imaging pixel 310 except for the filter, and the filter has the same white filter as the focus detection pixel. The light receiving area of the focus detection pixel 317 is a square that is twice the size of the focus detection pixels 313, 314, 315, and 316, and is virtually at the pixel position where the focus detection pixel 317 (third focus detection pixel) is arranged. When the focus detection pixels 313 and 314 or the focus detection pixels 315 and 316 are arranged, the data of the focus detection pixel 317 is a value obtained by adding the data of the virtual focus detection pixels 313 and 314, or the virtual This is a value obtained by adding data of typical focus detection pixels 313 and 314.

  FIG. 15 is a diagram illustrating an area of 8 pixels × 8 pixels centering on a pixel position where the first focus detection pixel array and the second focus detection pixel array intersect. The data of the first focus detection pixel array is indicated by α14, α24,..., Α84 as shown in the figure, and the data of the second focus detection pixel array is indicated by β41, β42,. Yes.

If the data of the focus detection pixel 317 (third focus detection pixel) is η44, the data α44 of the virtual first focus detection pixel 313 and the focus detection pixel 317 at the pixel position where the focus detection pixel 317 is arranged are The data β44 of the virtual second focus detection pixel 313 at the arranged pixel position is calculated as follows.
α44 = η44− (α34 + α54) / 2 (17)
β44 = η44− (β43 + β45) / 2 (18)

  In the above embodiment, the interpolation accuracy of the data of the virtual second focus detection pixel is improved as compared with the case where the first focus detection pixel is arranged at the intersection pixel position.

<Each focus detection pixel has a pair of light receiving regions>
In the partially enlarged view of the image sensor 212 illustrated in FIG. 3, an example in which each pixel includes a pair of focus detection pixels 313 and 314 and a pair of focus detection pixels 315 and 316 each having one photoelectric conversion unit is illustrated. A pair of photoelectric conversion units may be provided in the focus detection pixel. FIG. 16 is a partially enlarged view of such an image sensor 212. The focus detection pixels 311 and 312 include a pair of photoelectric conversion units. The first focus detection pixel 311 is disposed at a pixel position where the pixel array of the first focus detection pixel 311 and the pixel array of the second focus detection pixel 312 intersect.

  The focus detection pixel 311 shown in FIG. 17A performs a function corresponding to the pair of the focus detection pixel 313 and the focus detection pixel 314 shown in FIGS. 6A and 6B, and the focus detection pixel shown in FIG. The detection pixel 311 performs a function corresponding to the pair of the focus detection pixel 315 and the focus detection pixel 316 shown in FIGS. As shown in FIGS. 17A and 17B, the focus detection pixels 311 and 312 include a microlens 10 and a pair of photoelectric conversion units 13 and 14 or a pair of photoelectric conversion units 15 and 16. The focus detection pixels 311 and 312 are provided with white filters. The spectral sensitivity characteristics of the focus detection pixels 311 and 312 are the total of the spectral sensitivity characteristics of a photodiode that performs photoelectric conversion and the spectral sensitivity characteristics of an infrared cut filter (not shown). Spectral sensitivity characteristics. In other words, the spectral sensitivity characteristic is the sum of the spectral sensitivity characteristics of the green pixel, red pixel, and blue pixel described above, and the optical wavelength region of the sensitivity includes the optical wavelength region of the sensitivity of the green pixel, red pixel, and blue pixel. ing.

  FIG. 18 is a cross-sectional view of the focus detection pixel 311 shown in FIG. 17A, in which a light shielding mask 30 is formed in proximity to the photoelectric conversion units 13 and 14, and an opening 30 d of the light shielding mask 30 is formed. The light beam converters 13 and 14 receive the light that has passed. A planarizing layer 31 is formed on the light shielding mask 30, and a white filter 39 is formed thereon. A planarizing layer 32 is formed on the white filter 39, and the microlens 10 is formed thereon. The shape of the photoelectric conversion units 13 and 14 limited to the opening 30d by the microlens 10 is projected forward to form a pair of distance measuring pupils. The photoelectric conversion units 13 and 14 are formed on the semiconductor circuit substrate 29. The structure of the focus detection pixel 312 is only the structure of the focus detection pixel 311 rotated by 90 degrees, and is basically the same as the structure of the focus detection pixel shown in FIG.

FIG. 19 is a diagram illustrating an 8 × 8 pixel region centering on a pixel position where the pixel array of the first focus detection pixel 311 and the pixel array of the second focus detection pixel 312 intersect. A pair of data of the arrangement of the first focus detection pixels 311 of three consecutive pixels including the intersection pixel positions is (A34, B34), (A44, B44), (A54, B54) as shown in the figure, and the intersection pixels Assuming that a pair of data of the array of the second focus detection pixels 312 of the two pixels sandwiching the position is (C43, D43), (C45, D45) as shown in the figure, a virtual second at the focus crossing pixel position is obtained. A pair of data (C44, D44) of the focus detection pixel 312 is calculated as follows.
S = 2 × (A44 + B44) / (C43 + C45 + D43 + D45) (19)
C44 = S × (C43 + C45) / 2 (20)
D44 = S × (D43 + D45) / 2 (21)

<A third focus detection pixel is arranged at the intersection pixel position>
FIG. 20 is a front view showing a detailed configuration of the image sensor 212 of another embodiment. The difference from FIG. 16 is that pixel positions (Bayer array) where the vertical focus detection pixel array (first focus detection pixel array) and the horizontal focus detection pixel array (second focus detection pixel array) intersect. The focus detection pixel 317 (the third focus detection pixel) is arranged at a position where the green pixel is to be arranged according to the arrangement rule (1).

  The focus detection pixel 317 has the same structure as the imaging pixel 310 except for the filter, and the filter has the same white filter as the focus detection pixel. The size of the light receiving region of the focus detection pixel 317 is the same as the size of the pair of light receiving portions of the focus detection pixel 312 and the pair of light receiving portions of the focus detection pixel 312, and the focus detection pixel 317 (third focus detection). When the focus detection pixel 311 or the focus detection pixel 312 is virtually disposed at the pixel position where the pixel) is disposed, the data of the focus detection pixel 317 is a pair of data of the virtual focus detection pixel 311. Or a value obtained by adding a pair of virtual focus detection pixel 312 data.

FIG. 21 is a diagram illustrating an 8 × 8 pixel region centered on a pixel position where the pixel array of the first focus detection pixel 311 and the pixel array of the second focus detection pixel 312 intersect. The data of the focus detection pixel 317 (third focus detection pixel) is η44, and a pair of data of the arrangement of the first focus detection pixels 311 above and below the crossing pixel position is (A34, B34), ( A54, B54), and the pair of data of the second focus detection pixels 312 at the left and right of the crossing pixel position are (C43, D43) and (C45, D45) as shown in the figure, the focus crossing The pair of data (A44, B44) of the virtual first focus detection pixel 311 and the pair of data (C44, D44) of the virtual second focus detection pixel 312 at the pixel position are calculated as follows. Is done.
S1 = 2 × η44 / (A34 + B34 + A54 + B54) (22)
A44 = S1 × (A34 + A54) / 2 (23)
B44 = S1 × (B34 + B54) / 2 (24)
S2 = 2 × η44 / (C43 + C45 + D43 + D45) (25)
C44 = S2 × (C43 + C45) / 2 (26)
D44 = S2 × (D43 + D45) / 2 (27)

<X-shaped focus detection area, cross pixel position = green>
FIG. 22 is a diagram showing a focus detection position (focus detection area) on the imaging screen of the interchangeable lens 202, and a focus detection pixel column on the image sensor 212, which will be described in detail later, is an imaging screen for focus detection. An example of a region (focus detection area, focus detection position) where an image is sampled is shown. In this example, focus detection areas 111 to 115 are arranged at the center on the rectangular shooting screen 100 and at five locations on the top, bottom, left, and right. The focus detection pixels are linearly arranged in a 45 ° obliquely upward and 45 ° obliquely upward direction with respect to the longitudinal direction of the focus detection area indicated by a rectangle. The focus detection pixel arrays arranged in the two directions intersect at the center of each focus detection area. At the intersecting pixel positions, focus detection pixels belonging to the focus detection pixel array arranged in a direction orthogonal to a straight line connecting the intersecting pixel position and the screen center are arranged.

  FIG. 23 is a front view showing a detailed configuration of the image sensor 212, and shows an enlarged vicinity of the focus detection area 114 on the image sensor 212. Imaging pixels 310 are densely arranged on the imaging element 212 in a two-dimensional square lattice pattern. The imaging pixel 310 includes a red pixel (R), a green pixel (G), and a blue pixel (B), and is arranged according to a Bayer arrangement rule. At the position corresponding to the focus detection area 114, the focus detection pixels 323 and 324 having the same pixel size as the image pickup pixel and provided with the white filter are alternately diagonally arranged so that the green pixels should be continuously arranged. Focus detection pixels 325 and 326, which are continuously arranged on a straight line in a 45 degree upward direction and provided with a white filter, are alternately arranged in a 45 degree oblique left upward direction in which green pixels should be continuously arranged. Are arranged on a straight line. The focus detection pixels 323 and 324 and the focus detection pixels 325 and 326 are arranged at the pixel positions where the green pixels are originally arranged, and the intersection pixel positions are also the pixel positions where the green pixels are supposed to be arranged. .

  As shown in FIG. 24A, which shows a front view, the focus detection pixel 323 has a rectangular half-lens 10 and a light-shielding mask, which will be described later. It is comprised from the photoelectric conversion part 23 restrict | limited to the upper right half at the time of equally dividing, and the white filter (not shown).

  Further, as shown in FIG. 24B, which shows a front view, the focus detection pixel 324 has a rectangular half-lens (the square is a diagonal line in the 45 ° upward direction with a square as the light receiving area by using a rectangular microlens 10 and a light shielding mask described later. And a white filter (not shown).

  When the front view of the focus detection pixel 323 and the front view of the focus detection pixel 324 are superimposed and displayed with the microlens 10 as a reference, the photoelectric conversion units 23 and 24 in which the light receiving area is limited by the light-shielding mask are inclined upward 45 degrees. It is lined up in the direction. Further, in FIGS. 24A and 24B, when the remaining part (broken line part) obtained by halving the square is added to the light receiving area part obtained by halving the square, a square having the same size as the light receiving area of the imaging pixel is obtained. .

  The front view of the focus detection pixels 325 and 326 is also merely a 90 ° rotation of the front view of the focus detection pixels 323 and 324. Basically, the focus detection pixels 323 and 324 shown in FIGS. This is the same as the front view.

  FIG. 25 is a diagram illustrating an 8 × 8 pixel region centered on a pixel position where the pixel array of the first focus detection pixels 323 and 324 and the pixel array of the second focus detection pixels 325 and 326 intersect. It is. The first focus detection pixel array data is indicated by E81, E72,..., E18 as shown in the figure, and the second focus detection pixel array data is indicated by F21, β32,. Yes. Since the first focus detection pixel 323 is arranged at the intersection pixel position, the data when the second focus detection pixel 325 is virtually arranged at this pixel position is F54.

The value obtained by adding the data of the first focus detection pixel 323 and the data of the first focus detection pixel 324 at the intersection pixel position is the data of the second focus detection pixel 325 and the data of the second focus detection pixel 326. Based on the premise that the second focus detection pixel 325 is virtually disposed at the intersection pixel position, the data F54 is obtained as follows.
F54 = E54 + (E45 + E63) / 2− (F43 + F65) / 2 (28)

In FIG. 25, when the imaging pixels are arranged according to the arrangement rule of the Bayer array, green pixels are arranged at the intersection pixel positions. If the data when a green pixel is virtually arranged at the intersection pixel position is G54, the data G54 is obtained by averaging the four green pixel data G34, G52, G56, and G74 that are closest to the intersection pixel position. Can do.
G54 = (G34 + G52 + G56 + G74) / 4 (29)

For data when a green pixel is virtually arranged at a pixel position that is one pixel away from the intersecting pixel position in an oblique direction, for example, if the data of the adjacent pixel position at 45 degrees to the right of the intersecting pixel position is G45 The data G45 can be obtained by averaging the four green pixel data G34, G25, G56, and G47 closest to the pixel position.
G45 = (G34 + G25 + G56 + G47) / 4 (30)

For data when a virtual green pixel is virtually placed at a pixel position that is two pixels away from the intersecting pixel position in an oblique direction, for example, data of a pixel position that is two pixels away diagonally 45 degrees to the right of the intersecting pixel position Assuming G36, the data G36 can be obtained by averaging six green pixel data G34, G25, G56, G47, G16, and G38 that are closest to the pixel position.
G36 = (G34 + G25 + G56 + G47 + G16 + G38) / 6 (31)

  In the above embodiment, since the focus detection pixels are arranged at the pixel positions of the green pixels arranged at a higher density than the blue pixels and the red pixels, the interpolation error of the imaged pixel data is less noticeable.

<X-shaped focus detection area, cross pixel position = blue>
FIG. 26 is a modification of the embodiment shown in FIG. 23, and shows a case where the pixel position where the blue pixel is originally supposed to be arranged is the cross pixel position. In such an arrangement, since the focus detection pixels are arranged at the pixel positions where the blue pixels and the red pixels are supposed to be arranged, the data of the virtual blue pixels and the virtual red pixels is the virtual blue pixels. Uniform interpolation calculation processing by averaging four blue pixel data or four red pixel data two pixels apart in the horizontal and vertical directions with reference to the pixel position of the pixel and the virtual red pixel It can ask for.

<Intersection of horizontal and diagonal focus detection pixel arrays>
In the above embodiment, the two focus detection pixel arrays intersect at right angles. However, they need not necessarily be at right angles. FIG. 27 is a front view illustrating a detailed configuration of the image sensor 212 according to the embodiment in which the horizontal focus detection pixel array and the focus detection pixel array of 45 degrees obliquely to the right cross, and the focus on the image sensor 212. The vicinity of the detection area is shown enlarged. Also for such a focus detection pixel array, data of virtual focus detection pixels at intersection pixel positions can be obtained in the same manner as in the above-described embodiment. Further, the number of focus detection pixels is not limited to two. For example, focus detection pixel arrays arranged in four directions, that is, a horizontal direction, a vertical direction, a diagonally upward 45 degree direction, and a diagonally upward 45 degree direction. The present invention can also be applied to a case where the two are crossed at one crossing pixel position.

<The shape of the light receiving area of the focus detection pixel is a semicircle>
In addition, it is not always necessary that the light receiving region of the photoelectric conversion unit of the imaging pixel is a square and the shape of the light receiving region of the photoelectric conversion unit of the focus detection pixel is a rectangle or a triangle obtained by dividing the square into two equal parts. For example, in the embodiment of FIG. 3, when the shape of the light receiving region of the photoelectric conversion unit 11 of the imaging pixel 310 is a circle as shown in FIG. 28E, the focus detection pixel 313 in FIG. The light receiving regions of the photoelectric conversion units 33, 34, 35, and 36 of the focus detection pixels 333, 334, 335, and 336 corresponding to 314, 415, and 316 are shown in FIGS. 28 (a), (b), (c), and (d). ), A semicircular region (photoelectric conversion units 33 and 34) obtained by dividing the light receiving region of the image pickup pixel 11 into two equal parts by a horizontal line, and a semicircular region (photoelectric conversion units 35 and 36) obtained by dividing the light receiving region by two vertical parts. can do.

  In the image sensor in the above-described embodiment, an example in which the focus detection pixel includes a white filter has been described. However, the present invention can be applied to a case where the same color filter (for example, a green filter) as that of the image capture pixel is provided. it can.

  In the image pickup device according to the above-described embodiment, an example in which the image pickup pixel includes a Bayer color filter is shown. However, the configuration and arrangement of the color filter are not limited to this, and the complementary color filter (green: G, yellow). : Ye, magenta: Mg, cyan: Cy) and other arrangements other than the Bayer arrangement. Further, the present invention can also be applied to a monochrome imaging device that does not include a color filter.

  In the above-described embodiment, a CCD image sensor, a CMOS image sensor, or the like can be applied as the imaging element.

  In the above-described embodiment, no optical element is arranged between the image sensor and the optical system, but a necessary optical element can be appropriately inserted. For example, an infrared cut filter, an optical low-pass filter, a half mirror, or the like may be installed.

  Note that the imaging apparatus is not limited to the digital still camera or the film still camera having the configuration in which the interchangeable lens is mounted on the camera body as described above. For example, the present invention can also be applied to a lens-integrated digital still camera, film still camera, or video camera. Furthermore, the present invention can be applied to a small camera module built in a mobile phone, a surveillance camera, a visual recognition device for a robot, an in-vehicle camera, and the like.

9, 10 Microlens 11, 11, 14, 15, 16, 23, 24, 33, 34, 35, 36 Photoelectric conversion part, 29 Semiconductor circuit board, 30 Shading mask, 30a, 30b, 30c, 30d Opening part, 31, 32 Flattening layer, 38 color filter, 39 White filter, 71, 73, 74 Light flux, 90 Exit pupil, 91 Optical axis of interchangeable lens, 93, 94 Distance pupil, 95 area, 100 Shooting screen, 101, 102 , 103, 111, 112, 113, 114, 115 Focus detection area, 201 Digital still camera, 202 Interchangeable lens, 203 Camera body, 204 Mount unit, 206 Lens drive control device, 208 Zooming lens, 209 lens, 210 For focusing Lens, 211 Aperture, 212 Image sensor, 213 Electrical contact, 214 Body drive system Device, 215 liquid crystal display element driving circuit, 216 liquid crystal display element, 217 eyepiece, 219 memory card, 310 imaging pixel, 311, 312, 313, 314, 315, 316, 317, 323, 324, 325, 326, 333, 334, 335, 336 Focus detection pixels

Claims (13)

A plurality of imaging pixels each outputting an imaging signal relating to a subject image and a plurality of focus detection pixels each outputting a focus detection signal relating to a divided pupil image are arranged according to a two-dimensional array, and the plurality of focus detection pixels are mutually connected. An image sensor arranged so that a plurality of focus detection pixel arrays formed by being arranged in a plurality of adjacent linear rows intersect at a predetermined pixel position;
Based on the focus detection signal output by at least one of the plurality of focus detection pixels arranged in the vicinity of the predetermined pixel position and the focus detection signal at the predetermined pixel position, Focus detection signal acquisition means for acquiring specific focus detection signal data at the predetermined pixel position included in the focus detection signal data array corresponding to each of the focus detection pixel arrays;
An imaging apparatus comprising: a focus detection unit configured to detect a focus adjustment state relating to the subject image by a pupil division type phase difference detection method based on the focus detection signal data array. The imaging device according to claim 1,
The plurality of focus detection pixel arrays include a first focus detection pixel array and a second focus detection pixel array;
The first focus detection pixel array includes the plurality of focus detection pixels that output the focus detection signals related to the divided pupil images arranged in a first direction,
The second focus detection pixel array includes the plurality of focus detection pixels that output the focus detection signals related to the divided pupil images arranged in a second direction,
The focus detection pixel arranged at the predetermined pixel position is one of the plurality of focus detection pixels that outputs the focus detection signal related to the divided pupil images arranged in the first direction,
The focus detection signal acquisition unit acquires the focus detection signal at the predetermined pixel position as the specific focus detection signal data included in the focus detection signal data array corresponding to the first focus detection pixel array. Based on the focus detection signals output from the plurality of focus detection pixels arranged in the second focus detection pixel array in the vicinity of the predetermined pixel positions and the focus detection signals at the predetermined pixel positions. And acquiring the specific focus detection signal data included in the focus detection signal data array corresponding to the second focus detection pixel array. The imaging device according to claim 1,
The plurality of focus detection pixel arrays include a first focus detection pixel array and a second focus detection pixel array;
The first focus detection pixel array includes the plurality of focus detection pixels that output the focus detection signals related to the divided pupil images arranged in a first direction,
The second focus detection pixel array includes the plurality of focus detection pixels that output the focus detection signals related to the divided pupil images arranged in a second direction,
The focus detection pixels arranged at the predetermined pixel positions are the plurality of focus detection pixels that output the focus detection signals related to the divided pupil images arranged in the first direction and the divided pupils arranged in the second direction. A focus detection pixel that is different from any of the plurality of focus detection pixels that output the focus detection signal for an image,
The focus detection signal acquisition unit is arranged in the first focus detection pixel array in the vicinity of the predetermined pixel position, and outputs the focus detection signal output from the plurality of focus detection pixels, and the predetermined pixel position. Based on the focus detection signal, the specific focus detection signal data included in the focus detection signal data array corresponding to the first focus detection pixel array is acquired, and the vicinity of the predetermined pixel position is acquired. Based on the focus detection signal output from the plurality of focus detection pixels arranged in the second focus detection pixel array and the focus detection signal at the predetermined pixel position, the second focus detection pixel array An image pickup apparatus that acquires the specific focus detection signal data included in the focus detection signal data array corresponding to In the imaging device according to claim 2 or 3,
The vicinity of the predetermined pixel position is a pixel position adjacent to the predetermined pixel position. In the imaging device according to claims 1 to 4,
Based on the focus detection signals output from the plurality of focus detection pixels and the imaging signals output from the plurality of imaging pixels adjacent to the plurality of focus detection pixels, the pixel positions of the plurality of focus detection pixels are Imaging signal interpolation means for interpolating the imaging signal;
An imaging apparatus, further comprising: a captured image generation unit configured to generate a captured image signal based on the imaging signal output from the plurality of imaging pixels and the imaging signal interpolated by the imaging signal interpolation unit. . The imaging device according to claim 2,
The two-dimensional array is a square lattice array,
The arrangement direction of the first focus detection pixel arrangement is a direction parallel to or perpendicular to one side of the outer shape of the imaging element,
An imaging apparatus, wherein an arrangement direction of the second focus detection pixel array is a direction orthogonal to an arrangement direction of the first focus detection pixel array. The imaging device according to claim 2,
The two-dimensional array is a square lattice array,
The array direction of the first focus detection pixel array is a 45 degree oblique direction with respect to one side of the outer shape of the image sensor,
An imaging apparatus, wherein an arrangement direction of the second focus detection pixel array is a direction orthogonal to an arrangement direction of the first focus detection pixel array. In the imaging device according to any one of claims 2 to 7,
The first focus detection pixel array receives a first focus detection pixel that receives one of a first pair of light beams that are incident on the image sensor and form the divided pupil image aligned in the first direction. And a second focus detection pixel that receives the other of the first pair of light fluxes, and the first focus detection pixel and the second focus detection pixel are alternately repeated to form the first focus detection pixel. An array arranged parallel to the direction of 1,
The second focus detection pixel array is a third focus detection pixel that receives one of a second pair of light beams that are incident on the image sensor and form the divided pupil image aligned in the second direction. And a fourth focus detection pixel that receives the other of the second pair of light fluxes, and the third focus detection pixel and the fourth focus detection pixel are alternately repeated. An image pickup apparatus, wherein the image pickup apparatus is arranged in parallel with the direction of 2. In the imaging device according to any one of claims 2 to 7,
The first focus detection pixel array includes a first light receiving unit configured to receive one of a first pair of light beams that are incident on the image sensor and form the divided pupil image arranged in the first direction. Including a fifth focus detection pixel having a second light receiving portion for receiving the other of the first pair of light beams, and the first light receiving portion and the second light receiving portion are alternately repeated. An array in which the fifth focus detection pixels are arranged so as to be arranged in parallel with the first direction,
The second focus detection pixel array includes a third light receiving unit that receives one of a second pair of light beams that are incident on the imaging element and form the divided pupils arranged in the second direction, and the third light receiving unit. Including a sixth focus detection pixel having a fourth light receiving portion for receiving the other of the second pair of light beams, and the third light receiving portion and the fourth light receiving portion are alternately repeated. An image pickup apparatus, wherein the sixth focus detection pixels are arranged so as to be arranged in parallel with the second direction. The imaging device according to claim 8 or 9,
Each of the first pair of light beams and the second pair of light beams is a light beam complementary to each other with respect to a photographing light beam that is incident on the image sensor and forms the subject image. In the imaging device according to any one of claims 1 to 10,
The plurality of imaging pixels include a green pixel having sensitivity to green light, a red pixel having sensitivity to red light, and a blue pixel having sensitivity to blue light, and the green pixel, the red pixel, and the blue pixel, The image pickup device is arranged on the image pickup device in accordance with a Bayer array formed by: The imaging device according to claim 11,
The imaging apparatus according to claim 1, wherein the predetermined pixel position matches a pixel position where the green pixel is to be arranged according to the Bayer array. The imaging device according to claim 2,
An optical system for forming the subject image on the image sensor;
A line segment connecting the optical axis position where the optical axis of the optical system and the light receiving surface of the imaging device intersect with the predetermined pixel position, and the first direction of the first focus detection pixel array are formed. One intersection angle that is larger than the other of the second intersection angle angles formed by the angle of the intersection angle of 1 and the line segment and the arrangement direction of the second focus detection pixel array is formed. The imaging apparatus, wherein the plurality of focus detection pixels included in the focus detection pixel array are arranged at the predetermined pixel position.

Images