JP2010129783A - Imaging element and imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sense the focus by reducing the probability of saturating a signal output of a focus detection element with respect to an adequate signal output of an imaging element in the same light receiving condition in an imaging device having a focus detection function of a pupil division type phase difference detection system. <P>SOLUTION: A signal output of focus detection pixels 313, 314 is made smaller than a signal output of an imaging pixel by an ND filter (neutral density filter) 34 disposed between a micro lens 10 and photoelectric converting parts 13, 14 in the focus detection pixels 313, 314. The ND filter 34 transmits light in the substantially entire wavelength region of visible light. Thereby, the focus detection performance is improved. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging element and an imaging apparatus.

An array of a plurality of focus detection pixels that generate a pair of image signals corresponding to a pair of images formed by a pair of light beams passing through the optical system are mixed in an array of imaging pixels having the same pixel size as the focus detection pixels. A so-called pupil division type position that includes an imaging means, generates an image signal by the output of the imaging pixel, and detects a focus adjustment state of the optical system based on a shift amount of the pair of image signals generated by the focus detection pixel. An imaging apparatus having a phase difference detection type focus detection function is known (see, for example, Patent Document 1).
JP-A-1-216306

  However, in the imaging apparatus described above, the configuration of the imaging pixel and the focus detection pixel is different, so that when the exposure is performed with the same exposure time, the output of the focus detection pixel is saturated even if the output of the imaging pixel is not saturated. In some cases, focus detection could be disabled. For example, when focus detection is performed simultaneously while displaying the output of the imaging pixel on the electronic viewfinder, if the exposure time is shortened so that the output of the focus detection pixel does not saturate, the output of the imaging pixel is insufficient and a dark image is obtained. Therefore, the exposure time is controlled so that the output of the image pickup pixel is appropriate. In such a case, the output of the focus detection pixel may be saturated and focus detection may become impossible.

An image pickup device according to a first aspect of the present invention receives a first microlens, a color filter that transmits light in a specific wavelength region in visible light, and a first light that receives light via the first microlens and the color filter. Different spectral components having a photoelectric conversion unit and a first signal output unit that amplifies and outputs an electric signal photoelectrically converted by the first photoelectric conversion unit, and generates an output signal corresponding to an optical image formed by the optical system A plurality of types of imaging pixels having sensitivity characteristics, a second microlens, a second photoelectric conversion means for receiving light via the second microlens, and an electrical signal photoelectrically converted by the second photoelectric conversion means A plurality of focus detection pixels that generate a pair of output signals corresponding to a pair of images formed by a pair of light fluxes that pass through the optical system and that have a second signal output unit that amplifies and outputs Of focus detection pixels under the light receiving conditions of Adjusting means for adjusting the signal level of the focus detection pixel so that the signal level of the focus detection pixel is lower than the signal level of the image pickup pixel, and the plurality of image pickup pixels and the plurality of focus detection pixels are two-dimensional. It is characterized by being arranged.
An image pickup apparatus according to a thirteenth aspect of the invention is based on the image pickup element according to the first aspect of the invention, an image generation means for generating image data relating to an optical image based on the signal output of the image pickup pixel, and the signal output of the focus detection pixel. And a focus detection means for detecting a focus adjustment state of the optical system.

  According to the present invention, since the signal output level of the focus detection pixel can be made smaller than the signal output level of the imaging pixel, it is possible to reduce the situation where the focus detection pixel output is saturated and focus detection becomes impossible.

  An imaging device and an imaging apparatus according to an embodiment of the present invention will be described. FIG. 1 is a cross-sectional view showing a configuration of a lens interchangeable digital still camera equipped with an image sensor according to an embodiment. A digital still camera 201 according to an embodiment includes an interchangeable lens 202 and a camera body 203, and various interchangeable lenses 202 are 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, an aperture 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 lens information is transmitted and the camera information is received 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. 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. The adjustment is repeated, and image signal processing and recording, camera operation control, and the like are performed. The body drive control device 214 communicates with the lens drive control device 206 via the electrical contact 213 to receive lens information and send camera information (defocus amount, aperture value, etc.).

  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 the 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 on the photographing screen of the interchangeable lens 202, and a region (focus detection) in which a focus detection pixel array on the image sensor 212 described later samples an image on the photographing screen when focus detection is performed. An example of an area and a focus detection position is shown. In this example, focus detection areas 101 to 103 are arranged at the center and three left and right positions on the rectangular shooting screen 100. The focus detection areas 101 to 103 indicated by rectangles extend in the vertical direction on the photographing screen 100, and the focus detection pixels are linearly arranged in the longitudinal direction of each focus detection area.

  Before describing the detailed configuration of the image sensor 212, the principle of the pupil division type phase difference detection method disclosed in Patent Document 1 will be described with reference to FIG.

  A plurality of focus detection pixels 111 are arranged on the imaging surface 110. The focus detection pixel 111 includes a microlens 112 and a pair of photoelectric conversion units 113 and 114. The pair of photoelectric conversion units 113 and 114 is projected by the microlens 112 onto the distance measuring pupil plane 120 at a distance d ahead of the imaging surface 110, thereby forming a pair of distance measuring pupils 123 and 124. In other words, the luminous flux of the distance measuring pupil 123 out of the light flux passing through the distance measuring pupil plane 120 at a distance d ahead of the imaging surface 110 is received by the photoelectric conversion unit 113 of the focus detection pixel 111 and is measured. Of the light beams passing through the pupil plane 120, the light beam of the distance measuring pupil 124 is received by the photoelectric conversion unit 114 of the focus detection pixel 111. The relative shift amount (phase difference, image shift amount) between the image signal of the photoelectric conversion unit 113 in the array of the focus detection pixels 111 and the image signal of the photoelectric conversion unit 114 is an image on the imaging surface. Since it changes according to the focus adjustment state of the optical system to be formed, the focus adjustment state of the optical system can be detected by calculating this shift amount by processing a pair of image signals generated by the focus detection pixels. .

  By the way, the pair of distance measurement pupils 123 and 124 do not have a distribution obtained by simply projecting the pair of photoelectric conversion units 113 and 114, but the light diffraction effect according to the aperture diameter (substantially coincides with the pixel size) of the microlens 111. Due to this, the distribution is blurred and has a base. In FIG. 3, when the pair of distance measurement pupils 123 and 124 are scanned in the alignment direction using the slit in the direction perpendicular to the alignment direction of the pair of distance measurement pupils 123 and 124, a pair of distance measurement pupil distributions 133 and 134 are obtained. . Due to the diffraction effect, the pair of distance measuring pupil distributions 133 and 134 have overlapping portions 135 at adjacent portions. As the ratio of the superimposing unit 135 increases with respect to the entire distance measurement pupil distribution 133 or 134, the pair of distance measurement pupils 123 and 124 are not completely separated, and the focus detection performance decreases. In particular, when the aperture value F value of the optical system is large and the aperture diameter is small, the pair of light beams transmitted through the optical system pass through the region in the vicinity of the optical axis in the pair of distance measuring pupils 123 and 124. Then, the light enters the focus detection pixel 111. For this reason, the pair of light fluxes used for focus detection is incompletely separated, so that the focus detection performance is deteriorated or the focus detection becomes impossible.

Table 1 shows the relationship between the aperture F value of the optical system and the diameter of the spread of the point image distribution by diffraction, and the Airy disk formula (diameter of point image = 1.22 × 2 × wavelength × F value). And the wavelength = 500 nm). For a bright optical system (small aperture F value), the diameter of the point image is on the order of μm, so that the resolution can be expected to be improved by setting the pixel size of the imaging pixel to be equal to or smaller than the diameter of the point image.

  On the other hand, as described above, when the pixel size is reduced, the influence of diffraction increases and the separation of the distance measuring pupil becomes incomplete, so that the focus detection performance is degraded.

Table 2 shows the pixel size (opening diameter D of the circular microlens) and the F value corresponding to the superimposition unit 135 obtained by dividing the distance d in FIG. 3 by the dimension x of the superposition unit 135 of the pair of distance measurement pupil distributions. The relationship is shown, and is obtained from the Airy disk equation (when F = D / (1.22 × 2 × wavelength) and wavelength = 500 nm). When the pixel size is 7 μm or less, the F value of the overlapping portion 135 is 5.7 or less.

  Since the open F value of many interchangeable lenses for cameras is set to F5.6, when these interchangeable lenses are used, if the pixel size of the focus detection pixel is 7 μm or less, the aperture of F5.6 is set. Since the pair of focus detection light fluxes that pass through overlap each other, a drop in focus detection performance becomes obvious. Further, when the pixel size of the focus detection pixel is 4 μm or less, a pair of focus detection light beams passing through the aperture of approximately F2.8 are superimposed over the entire area, so that the focus detection performance is significantly deteriorated.

  FIG. 4 is a front view showing a detailed configuration of the image sensor 212, and shows an enlarged vicinity of the focus detection area 101 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. In the position corresponding to the focus detection area 101, focus detection focus detection pixels 313 and 314 having the same pixel size as the imaging pixels are alternately arranged, and the green pixels and the blue pixels originally should be continuously arranged in the vertical direction. Arranged continuously on a straight line.

  FIG. 5 is a diagram showing the shape of the microlens of the image pickup pixel and the focus detection pixel. The microlens 10 has a shape cut out from a circular microlens 9 larger than the pixel size into a square shape corresponding to the pixel size. The cross section 10A in the diagonal direction passing through the optical axis of the microlens 10 and the cross section 10B in the horizontal direction passing through the optical axis of the microlens 10 have shapes shown in FIG.

  By making the shape of the microlens rectangular (square) in this way, the spread of the distance measuring pupil due to the diffraction effect described above can be reduced and the focus detection performance can be improved, but in the case of a circular lens of the same pixel size Since the aperture area increases, the output of the focus detection pixel increases in the case of the rectangular microlens.

  The pixel size of the imaging pixel and the focus detection pixel is 3μ. Although not shown, the configuration in the vicinity of the focus detection areas 102 and 103 is the same as the configuration shown in FIG.

  As shown in FIG. 6A, the imaging pixel 310 includes a rectangular microlens 10, a photoelectric conversion unit 11 whose light receiving area is limited 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 the respective spectral sensitivities have the characteristics shown in FIG. In the image pickup device 212, image pickup pixels 310 having respective color filters are arranged in a Bayer array.

  As shown in FIG. 6B, the focus detection pixel 313 includes a rectangular microlens 10, a photoelectric conversion unit 13 in which a light receiving area is limited by a light shielding mask described later, and an ND filter (not shown). The shape of the photoelectric conversion unit 13 whose light receiving area is limited by the mask is rectangular. Further, as shown in FIG. 6C, the focus detection pixel 314 includes a rectangular microlens 10, a photoelectric conversion unit 14 whose light receiving area is limited by a light shielding mask described later, and an ND filter (not shown) described later. The shape of the photoelectric conversion unit 14 that is configured and whose light receiving area is limited by a light shielding mask having a smaller opening than the light shielding mask of the imaging pixel 310 is rectangular. When the focus detection pixel 313 and the focus detection pixel 314 are displayed with the microlens 10 superimposed, the photoelectric conversion units 13 and 14 whose light receiving areas are limited by the light shielding mask are arranged in the vertical direction.

  FIG. 9 is a cross-sectional view of the imaging pixel 310. 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. 10 is a cross-sectional view of the focus detection pixels 313 and 314. 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 photoelectric 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 an ND filter (neutral density filter) 34 is formed thereon. A planarizing layer 32 is formed on the ND filter 34, 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.

  As described above, the focus detection pixels 313 and 314 are not provided with a color filter for performing focus detection on all colors, but instead are provided with an ND filter 34 for reducing the amount of incident light. The spectral characteristics are shown in FIG. In other words, the spectral characteristics are obtained by adding the spectral characteristics of the green pixel, red pixel, and blue pixel shown in FIG. 7, and the light wavelength region of the sensitivity includes the light wavelength regions of the sensitivity of the green pixel, red pixel, and blue pixel. ing. The density of the ND filter 34 is, for example, 3/4 (75%) of the output level of the focus detection pixels 313 and 314 with respect to the output level of the green pixel of the imaging pixel 310 when the imaging device 212 is irradiated with white light. It is determined to be as follows. This is due to the action of the ND filter 34 described below.

  The first function of the ND filter 34 is as follows. As described above, the imaging pixel 310 includes the color filter 38 having the spectral sensitivity shown in FIG. Therefore, the amount of light incident on the photoelectric conversion unit 11 is reduced by the color filter 38. On the other hand, since there is no color filter in the focus detection pixels 313 and 314 and the above-described reduction in the amount of incident light does not occur, the output level of the focus detection pixels 313 and 314 may exceed the output level of the imaging pixel 310. . In order to prevent this, the ND filter 34 of the focus detection pixel reduces the amount of light incident on the photoelectric conversion units 13 and 14.

  The second function of the ND filter 34 is as follows. Vignetting of the focus detection light flux occurs in a region where the image height is high on the screen (focus detection areas 102 and 103), the output balance of the pair of focus detection pixels 313 and 314 is lost, and the output level of one focus detection pixel increases. Even in this case, the output level of the green pixel in the imaging pixel 310 is not exceeded.

  The focus detection pixels 313 and 314 are arranged in a column where B and G of the imaging pixel 310 are to be arranged according to the arrangement rule of the Bayer array. This is because when an interpolation error occurs in the interpolation processing for obtaining the image signal at the position of the focus detection pixels 313 and 314, the interpolation error of the blue pixel is compared with the interpolation error of the red pixel due to human visual characteristics. This is because it is not conspicuous.

  The imaging pixel 310 is designed in such a shape that the photoelectric conversion unit 11 receives all the light flux that passes through the exit pupil diameter (for example, F1.0) of the brightest interchangeable lens by the microlens 10. In addition, the focus detection pixels 313 and 314 are designed in such a shape that the photoelectric conversion units 13 and 14 respectively receive a pair of focus detection light beams that pass through a pair of predetermined regions of the exit pupil of the interchangeable lens by the microlens 10. Is done.

  FIG. 11 shows a configuration of a pupil division type phase difference detection type focus detection optical system using a microlens. The focus detection pixel portion is shown in an enlarged manner. In FIG. 11, the exit pupil 90 is set at a position of a distance d forward from the microlens arranged on the planned imaging plane of the interchangeable lens 202 (see FIG. 1). This distance d is a distance determined according to the curvature and refractive index of the microlens, the distance between the microlens and the photoelectric conversion unit, and is referred to as a distance measuring pupil distance in this specification. FIG. 11 also shows the optical axis 91 of the interchangeable lens, the microlens 10, the photoelectric conversion units 13 and 14, focus detection pixels 313 and 314, the photographing light beam 71, and the focus detection light beams 73 and 74.

  The distance measuring pupil 93 is a projection of the region of the opening 30b by the microlens 10. Similarly, the distance measuring pupil 94 is obtained by projecting the region of the opening 30 c by the microlens 10. In FIG. 11, the distance measuring pupils 93 and 94 are shown in clear areas for easy understanding, but in reality, the shapes of the openings 30 b and 30 c are enlarged and projected and become blurred due to diffraction. .

  In FIG. 11, five focus detection pixels adjacent to the photographing optical axis are schematically illustrated, but the focus detection area 102 in the periphery of the screen also in the other focus detection pixels and imaging pixels of the focus detection area 101. , 103 also, the photoelectric conversion units are configured to receive light beams that arrive at the microlenses from the corresponding distance measurement pupils 93 and 94, respectively. The arrangement direction of the focus detection pixels is made to coincide with the arrangement direction of the pair of distance measuring pupils, that is, the arrangement direction of the pair of photoelectric conversion units.

  The microlens 10 is disposed in the vicinity of the planned imaging plane of the interchangeable lens 202 (see FIG. 1), and the shape of the openings 30b and 30c disposed in the vicinity of the photoelectric conversion units 13 and 14 by the microlens 10 is micro. The projection is performed on the exit pupil 90 separated from the lens 10 by the distance measurement pupil distance d, and the projection shape forms distance measurement pupils 93 and 94.

  The photoelectric conversion unit 13 passes through the distance measuring pupil 93 and outputs a signal corresponding to the intensity of the image formed on the microlens 10 by the light flux 73 directed to the microlens 10 of the focus detection pixel 313. Further, the photoelectric conversion unit 14 outputs a signal corresponding to the intensity of the image formed on the microlens 10 by the light flux 74 that passes through the distance measuring pupil 94 and travels toward the microlens 10 of the focus detection pixel 314.

  A large number of the two types of focus detection pixels described above are arranged in a straight line, and the output of the photoelectric conversion unit of each pixel is grouped into a distance measurement pupil 93 and an output group corresponding to the distance measurement pupil 94, thereby measuring the distance measurement pupil 93 and the measurement pupil 93. Information on the intensity distribution of the pair of images formed on the pixel array by the focus detection light beams that respectively pass through the distance pupil 94 is 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 calculation 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 to the image displacement amount, the current image formation plane (micrometer on the planned image formation plane) A deviation (defocus amount) of the imaging plane at the focus detection position corresponding to the position of the lens array is calculated.

  FIG. 12 is a diagram for explaining the state of the imaging light beam received by the imaging pixel 310 of the imaging device 212 shown in FIG. 4 in comparison with FIG. 11, and description of portions overlapping those in FIG. 11 is omitted.

  The imaging pixel 310 includes the microlens 10 and the photoelectric conversion unit 11 disposed behind the microlens 10, and the shape of the opening 30 a (see FIG. 9) disposed close to the photoelectric conversion unit 11 is measured from the microlens 10. Projection is performed on the exit pupil 90 separated by the distance pupil distance d, and the projection shape forms a region 95 that is substantially circumscribed by the distance measurement pupils 93 and 94.

  The photoelectric conversion unit 11 outputs a signal corresponding to the intensity of the image formed on the microlens 11 by the imaging light beam 71 that passes through the region 95 and travels toward the microlens 10.

  A circuit configuration when the image sensor 212 is configured as a CMOS image sensor will be described. FIG. 13 is a conceptual diagram of a circuit configuration of the image sensor 212.

  In a CMOS image sensor, as is well known, the charge accumulation timing between pixels on the same scan line is the same, but the charge accumulation timing between pixels on different scan lines is different. If the charge accumulation timing is different in the focus detection pixel array described above, when focus detection is performed on a moving subject, the simultaneity (identity) of a pair of images generated by the focus detection pixel array is lost. In order to align the charge accumulation timing of the focus detection pixel array, in this embodiment, the scanning line direction of the image sensor 212 that is a CMOS image sensor is set to detect a detection error when detecting an image shift described later. They are set so as to be aligned in the same direction as the focus detection areas 101 to 103 in FIG. 2 (the short side direction of the rectangular screen). However, it is not limited to that.

  In FIG. 13, the circuit configuration of the image sensor 212 is simplified to a layout of 8 pixels in the horizontal direction × 4 pixels in the vertical direction. In the vertical direction, focus detection pixels 313 and 314 (◯: two pixels indicated by circles) are arranged at the second and third pixels in the sixth column, and the imaging pixels 310 (□: pixels indicated by squares) are at other positions. Arranged. The detailed operation of the circuit of FIG. 13 will be described below.

  In FIG. 13, a line memory 320 is a buffer that samples and holds pixel signals of pixels for one column and temporarily holds them, and a control in which the horizontal scanning circuit 522 generates pixel signals of the same column output to the signal line Vout. Sample and hold simultaneously based on the signal ΦS. The pixel signal held in the line memory 320 is reset in synchronization with the rise of the control signals ΦH1 to ΦH8.

  Outputs of pixel signals from the imaging pixel 310 and the focus detection pixels 313 and 314 are controlled independently for each column by control signals (ΦH1 to ΦH8) generated by the horizontal scanning circuit. Pixel signals of the pixels in the column selected by the control signals (ΦH1 to ΦH8) are output to the signal line 501. The pixel signals held in the line memory 320 are sequentially transferred to the output circuit 330 by the control signals (ΦV1 to ΦV4) generated by the vertical scanning circuit 502, amplified by the amplification degree set by the output circuit 330, and output to the outside. The After the pixel signal is sampled and held, the imaging pixel 310 is reset by a control signal (ΦR1 to ΦR8) generated by the reset circuit 504, and starts charge accumulation for the next pixel signal.

  FIG. 14 is a diagram illustrating a basic circuit configuration for one photoelectric conversion unit in the imaging pixel 310 and the focus detection pixels 313 and 314. The photoelectric conversion unit is composed of a photodiode (PD). The charge accumulated in the PD is accumulated in a floating diffusion layer (floating diffusion: FD). The FD is connected to the gate of the amplification MOS transistor (AMP), and the AMP generates a signal corresponding to the amount of charge accumulated in the FD.

  The FD portion is connected to the power supply voltage Vdd via the reset MOS transistor SW1, and when the reset MOS transistor SW1 is turned on by the control signal ΦRn, the charges accumulated in the FD and PD are cleared and set in a reset state. The output of AMP is connected to the vertical output line Vout via the row selection MOS transistor SW2. When the row selection MOS transistor SW2 is turned on by the control signal ΦSn, the output of AMP is output to the vertical output line Vout.

  FIG. 15 is an operation timing chart of the image sensor 212 shown in FIG. The imaging pixels 310 in the first column are selected by the control signal ΦH1 generated by the horizontal scanning circuit 522, and the pixel signals of the selected imaging pixels 310 are output to the signal line 501. The pixel signal in the first column output to the signal line 501 by the control signal ΦS generated in synchronization with the control signal ΦH1 is temporarily held in the line memory 320. The pixel signals of the imaging pixels 310 in the first column held in the line memory 320 are transferred to the output circuit 330 according to the control signals ΦV1 to ΦV4 sequentially issued from the vertical scanning circuit 502, and with the amplification degree set by the output circuit 330. Amplified and output to the outside.

  When the transfer of the pixel signals of the imaging pixels 310 in the first column to the line memory 320 is completed, the imaging pixels 310 in the first column are reset by the control signal ΦR1 issued from the reset circuit 504, and the falling edge of the control signal ΦR1 Then, the next charge accumulation of the imaging pixels in the first column is started. When the output of the pixel signal of the imaging pixel 310 in the first column from the output circuit 330 is completed, the imaging pixel 310 in the second column is selected by the control signal ΦH2 generated by the horizontal scanning circuit 522, and the selected imaging pixel 310 is selected. The pixel signal is output to the signal line 501. Thereafter, similarly, the pixel signal of the imaging pixels 310 in the second column is held, the focus detection pixels 313 and 314 are reset, the pixel signal is output, and the next charge accumulation is started.

  Subsequently, the pixel signals of the imaging pixels 310 and the focus detection pixels 313 and 314 in the third to eighth columns are retained, the imaging pixels 310 and the focus detection pixels 313 and 314 are reset, and the imaging pixels 310 and the focus detection pixels 313 and 314 are reset. The pixel signal is output and the next charge accumulation is started. When the output of the pixel signals of all the pixels is completed, the operation returns to the first column again and the above operation is repeated periodically. Further, by changing the pulse width of the control signals ΦR1 to ΦR8, it is possible to adjust the charge accumulation time (exposure time) of the imaging pixel 310 and the focus detection pixels 313 and 314.

  Through the operation as described above, pixels are scanned from the bottom to the top of the rectangular imaging region 100 of the image sensor 310, the scanned pixel signals are sequentially output to the outside, and the scanning lines are shifted from the left to the right of the screen. To sequentially output the pixel signals of the entire screen to the outside. Since the direction of the scanning line coincides with the short side direction of the rectangular screen and also coincides with the arrangement direction of the focus detection pixels 313 and 314, the same charge accumulation timing is obtained in the focus detection pixels 313 and 314 arranged in the same column. Can be maintained.

  FIG. 16 is a flowchart illustrating an imaging operation of the digital still camera (imaging device) 201 according to the embodiment. 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, the data of the imaging pixels is read out and displayed on the electronic viewfinder. In subsequent step S120, a pair of image data corresponding to the pair of images is read from the focus detection pixel array. 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 S130, an image shift detection calculation process (correlation calculation process, phase difference detection process) to be described later is performed based on the read pair of image data, and the image shift amount is calculated and converted into a defocus amount. 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 (F set by the photographer or automatically). Value). When the aperture control is finished, the image sensor 212 is caused to perform an imaging operation, and image data is read from the image pickup pixel 310 and all the focus detection pixels 313 and 314 of the image pickup element 212.

  In step S180, pixel interpolation of pixel data at each pixel position in the focus detection pixel row is performed based on the data of the imaging pixels 310 around the focus detection pixels 313 and 314 and the data of the focus detection pixels 313 and 314. In subsequent step S190, image data composed of the data of the imaging pixel 310 and the interpolated data 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 S130 of FIG. 16 will be described below.

In the pair of images detected by the focus detection pixels 313 and 314, the distance measurement pupils 93 and 94 may be displaced by the aperture of the lens and the light amount balance may be lost. A type of correlation operation that can maintain the above is applied. Japanese Patent Application Laid-Open (JP-A) No. 2004-A-1993 based on the application of the present applicant for a pair of data strings (A1 ₁ ,..., A1 _M , A2 ₁ ,..., A2 _M : M is the number of data) The correlation calculation formula (1) disclosed in 2007-333720 is performed to calculate the correlation amount C (k).

In equation (1), Σ operations are accumulated for n. 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. 17A, 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. 17A). Minimal (the smaller the value, the higher the correlation). The shift amount x that gives the minimum value C (x) when the correlation amount is regarded as continuous is obtained using the three-point interpolation method according to the equations (2) to (5).

  Whether the shift amount x calculated by the equation (2) is reliable is determined as follows. As shown in FIG. 17B, when the degree of correlation between a pair of data is low, the minimum value C (x) of the interpolated correlation amount increases. Therefore, when C (x) is equal to or greater than a predetermined threshold, it is determined that the reliability of the calculated shift amount x is low, and the calculated shift amount x is canceled. Alternatively, in order to normalize C (x) with the contrast of data, when the value obtained by dividing C (x) by SLOP that is proportional to the contrast is equal to or greater than a predetermined value, the reliability of the calculated shift amount x The calculated shift amount x is cancelled.

Alternatively, if SLOP that is 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 x is low, and the calculated shift amount x is canceled. . As shown in FIG. 17C, when the correlation between the pair of data is low and there is no drop in the correlation amount C (k) between the shift range _kmin and _kmax , the minimum value C (x) is obtained. In such a case, it is determined that the focus cannot be detected. When it is determined that the calculated shift amount x is reliable, it is converted into the image shift amount shft by the equation (6).

In Expression (6), PY is twice the pixel pitch (detection pitch) of the focus detection pixels 313 and 314. The image shift amount calculated by Expression (6) is multiplied by a predetermined conversion coefficient Kd to convert it to a defocus amount def.

  In the above embodiment, the focus detection performance deterioration due to diffraction is prevented by making the shape of the micro lens of the focus detection pixels 313 and 314 rectangular. By disposing an ND filter as an adjustment means in the focus detection pixels 313 and 314, it is possible to prevent the output of the focus detection pixels 313 and 314 from increasing due to an increase in the aperture area of the microlens and the like and exceeding the output of the imaging pixel 310, It is guaranteed that the output of the focus detection pixels 313 and 314 is 3/4 or less of the output of the imaging pixel 310 in the same exposure time. As a result, the pair of focus detection light beams are unevenly vignetted in the region corresponding to the peripheral portion of the screen range, and the amount of light beams incident on one of the pair of focus detection pixels 313 and 314 increases. In addition, the probability that the outputs of the focus detection pixels 313 and 314 are saturated can be reduced.

  In an image with a wide dynamic range, the output of the imaging pixel 310 may saturate in an area corresponding to a part on the screen. However, the focus detection pixel is also in an area where the output of the imaging pixel 310 slightly exceeds the saturation level. Since the outputs of 313 and 314 are not yet saturated, focus detection is possible even in this region.

The output of the focus detection pixels 313 and 314 is also used for pixel interpolation processing. However, the probability of saturation of the output of the focus detection pixels 313 and 314 due to the vignetting of the focus detection light beam is reduced, so that the pixel interpolation performance is improved. Image quality is improved.
<< Other Embodiments of the Invention >>

  In the above-described embodiment of the present invention, by providing the focus detection pixels 313 and 314 with the ND filter, the signal output level of the focus detection pixels 313 and 314 has the signal output level of the imaging pixel 310 under the same exposure condition. Although it is adjusted so that it does not exceed the value, it may be adjusted by means other than this.

  FIG. 18 is a diagram showing a configuration of the focus detection pixel 313 corresponding to FIG. 6B, and a light shielding member 39 for adjusting the light amount is added instead of the ND filter. A focus detection pixel 314 (not shown) is similarly configured. FIG. 19 is a cross-sectional view of the focus detection pixels 313 and 314 shown in FIG. 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 receive light that has passed through the openings 30 b and 30 c of the light shielding mask 30. A planarization layer 31 is formed on the light shielding mask 30, and a light shielding member 39 is formed thereon. A planarizing layer 32 is formed on the light shielding member 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 light shielding member 39 is disposed in the vicinity of the microlens 10 and shields the light beam passing through the vicinity of the optical axis of the microlens 10. As a result, the amount of light can be adjusted, and blurring can be reduced in the diffraction of the projected images of the openings 30b and 30c by the effect of apodization, thereby improving the pupil division performance.

  In the configuration of the focus detection pixels 313 and 314, a half mirror (beam splitter) member is disposed in the optical path from the microlens 10 to the photoelectric conversion units 13 and 14, and a part of the light beam incident on the focus detection pixels 313 and 314 is obtained. May be adjusted so that the signal output level of the focus detection pixels 313 and 314 does not exceed the signal output level of the imaging pixel 310 under the same exposure conditions. Specifically, a thin film having a half mirror function can be formed on the surface of the microlens 10 of the focus detection pixels 313 and 314 and the surfaces of the photoelectric conversion units 13 and 14 by a multilayer film or the like.

  In each of the embodiments of the present invention described above, optical means are used so that the signal output level of the focus detection pixels 313 and 314 does not exceed the signal output level of the imaging pixel 310 under the same exposure conditions. However, it may be adjusted by other means.

  For example, in the circuit configuration of the pixel shown in FIG. 14, the same exposure is achieved by making the amplification degree of the amplification MOS transistor (AMP) of the focus detection pixels 313 and 314 lower than the amplification degree of the amplification MOS transistor (AMP) of the imaging pixel 310. It is possible to adjust so that the signal output level of the focus detection pixels 313 and 314 does not exceed the signal output level of the imaging pixel 310 under the conditions.

  Further, by setting the quantum efficiency of the photoelectric conversion units 13 and 14 of the focus detection pixels 313 and 314 to be lower than the quantum efficiency of the photoelectric conversion unit 11 of the imaging pixel 310, the signal output of the focus detection pixels 313 and 314 under the same exposure conditions. The level can be adjusted so as not to exceed the signal output level of the imaging pixel 310. Specifically, when a photodiode (PN junction) serving as a photoelectric conversion portion is formed on a semiconductor substrate, the quantum efficiency can be controlled by controlling the depth.

  Further, by setting the charge accumulation time of the focus detection pixels 313 and 314 to be shorter than the charge accumulation time of the imaging pixel 310, the signal output level of the focus detection pixels 313 and 314 becomes the signal output level of the imaging pixel 310 under the same exposure condition. It is possible to adjust so as not to exceed.

  FIGS. 20 and 21 are circuit configurations and operation timing charts of the image sensor 310 corresponding to FIGS. 13 and 15, and description of overlapping portions is omitted. The difference between FIG. 20 and FIG. 13 is that the image pickup pixel 310 and the focus detection pixels 313 and 314 in the sixth column are reset by different control signals ΦR6 and ΦR6a generated by the reset circuit 504, and charge for the next pixel signal is obtained. This is the point where accumulation starts.

  With this configuration, as shown in FIG. 21, the reset of the focus detection pixels 313 and 314 in the sixth column rises simultaneously with the control signal ΦR6 and is controlled by the control signal ΦR6a falling after the control signal ΦR6. As a result, the charge accumulation time of the image pickup pixel 310 becomes the time T1 from the fall to the rise of the control signals ΦR1 to ΦR8, while the charge accumulation time of the focus detection pixels 313 and 314 is the time from the fall to the rise of the control signal ΦR6a. T2 (shorter than time T1), and the signal output level of the focus detection pixels 313 and 314 becomes smaller than the signal output level of the imaging pixel 310 under the same exposure condition. The time T2 is set by the reset circuit 522 so as to be 3/4 or less of the time T1.

  In the imaging device 212 illustrated in FIG. 4, an example in which each pixel includes a pair of focus detection pixels 313 and 314 having one photoelectric conversion unit is illustrated. However, a pair of photoelectric conversion units are provided in one focus detection pixel. It may be. FIG. 22 is a partially enlarged view of such an image sensor 212. The focus detection pixel 311 includes a pair of photoelectric conversion units. The focus detection pixel 311 illustrated in FIG. 23 performs a function corresponding to the pair of the focus detection pixel 313 and the focus detection pixel 314 illustrated in FIGS. 6B and 6C. The focus detection pixel 311 includes a microlens 10 and a pair of photoelectric conversion units 13 and 14 as shown in FIG. The focus detection pixel 311 is not provided with a color filter in order to increase the amount of light, and its spectral characteristic is a spectral that combines the spectral sensitivity of a photodiode that performs photoelectric conversion and the spectral characteristic of an infrared cut filter (not shown). Characteristics (see FIG. 7). In other words, the spectral characteristics are obtained by adding the spectral characteristics of the green pixel, red pixel, and blue pixel shown in FIG. 8, and the light wavelength region of the sensitivity includes the light wavelength regions of the sensitivity of the green pixel, red pixel, and blue pixel. ing.

  FIG. 24 is a cross-sectional view of the focus detection pixel 311 shown in FIG. 23, in which a light shielding mask 30 is formed close to the photoelectric conversion units 13 and 14, and light that has passed through the opening 30 d of the light shielding mask 30 is reflected. The photoelectric conversion units 13 and 14 receive light. A planarizing layer 31 is formed on the light shielding mask 30, and an ND filter 34 is formed thereon. A planarizing layer 32 is formed on the ND filter 34, 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.

  In the above-described embodiment, no optical element is arranged between the image sensor 212 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. In the case of the configuration of the imaging device as shown in FIG. 4, the characteristics of the optical low-pass filter are such that the high-frequency cut effect of the optical low-pass filter is more effective in the alignment direction of the focus detection pixels than in the direction perpendicular to the alignment direction of the focus detection pixels. By setting, the adverse effect on the focus detection accuracy when an image having a high frequency component enters between the focus detection pixels can be mitigated.

  In the above-described embodiment, the configuration shown in the cross-sectional view of the imaging pixel 310 shown in FIG. 9 and the cross-sectional views of the focus detection pixels 313, 314, and 311 shown in FIGS. By making the thickness of the filter 38 and the ND filter 34 substantially equal, each distance between the photoelectric conversion units 13, 14, 11 and the microlens 10 can be made equal. Further, since the focus detection pixels 313, 314, and 311 are provided with the ND filter 34 instead of the color filter 38 in the image pickup pixel 310, the manufacturing process of the image pickup pixel 310 and the focus detection pixels 313, 314, and 311 is omitted. It can be shared. Therefore, an integrated microlens array can be easily manufactured by the focus detection pixels 313, 314, 311 and the imaging pixel 310. On the other hand, as described above, by providing means other than the ND filter 34 to the focus detection pixels 313, 314, 311, the signal output level of the focus detection pixels 313, 314, 311 is the signal of the imaging pixel 310 under the same exposure conditions. It is possible to adjust so as not to exceed the output level. In that case, by providing the focus detection pixels 313, 314, and 311 with a colorless filter or the like instead of the ND filter 34, the distances between the photoelectric conversion units 13, 14, and 11 and the microlens 10 are made equal to each other. It is preferable that the manufacturing process of the 310 and the focus detection pixels 313, 314, and 311 can be made substantially common.

  In the imaging element 212 in the above-described embodiment, an example in which the imaging pixel includes a Bayer color filter is shown, but the configuration and arrangement of the color filter are not limited to this, and a complementary color filter (green: G, yellow). : Ye, magenta: Mg, cyan: Cy) and other arrangements other than the Bayer arrangement.

  In the focus detection pixel in the above-described embodiment, an example in which the opening shape of the light shielding mask is rectangular has been described. However, the opening shape of the light shielding mask is not limited thereto, and may be other shapes, for example, half It can also be a circle, ellipse or polygon.

  Note that the imaging apparatus is not limited to a digital still camera or a film still camera in which an interchangeable lens is mounted on the camera body as described above. For example, the present invention can 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.

1 is a cross-sectional view illustrating a configuration of a lens interchangeable digital still camera equipped with an image sensor according to an embodiment. The figure which shows the focus detection position on the imaging | photography screen of an interchangeable lens. The figure explaining the principle of a pupil division type phase difference detection system. The partial enlarged front view which shows the detailed structure of an image pick-up element. The figure which shows the shape of the micro lens of an imaging pixel and a focus detection pixel. The front view of an imaging pixel and a focus detection pixel. The figure which shows the spectral characteristic of a green pixel, a red pixel, and a blue pixel. The figure which shows the spectral characteristic of a focus detection pixel. Sectional drawing of an imaging pixel. Sectional drawing of a focus detection pixel. The figure which shows the structure of the focus detection optical system of the pupil division type phase difference detection system using a micro lens. The figure which shows the mode of the imaging | photography light beam which an imaging pixel receives. FIG. 6 is a diagram showing a simplified circuit configuration of an image sensor. The figure which shows the basic circuit structure with respect to one photoelectric conversion part in an imaging pixel and a focus detection pixel. The operation timing chart of an image sensor. The flowchart which shows the imaging operation of a digital still camera. The figure which shows the relationship of the correlation amount C (k) with respect to the shift amount k of a pair of data. The figure which shows the structure of the focus detection pixel in the image pick-up element of other embodiment. Sectional drawing of a focus detection pixel. FIG. 6 is a diagram showing a simplified circuit configuration of an image sensor. The operation timing chart of an image sensor. The partial enlarged front view which shows the detailed structure of an image pick-up element. The front view of a focus detection pixel. Sectional drawing of a focus detection pixel.

Explanation of symbols

100 Shooting screen, 101 to 103, Focus detection area, 110 Imaging surface, 111 Focus detection pixel, 112 Micro lens, 113, 114 Photoelectric conversion unit, 120 Distance pupil surface, 123, 124 Distance pupil, 133, 134 Distance measurement Pupil distribution, 135 superimposing unit, 201 digital still camera, 202 interchangeable lens, 203 camera body, 204 mount unit, 206 lens driving control device, 208 zooming lens, 209 lens, 210 focusing lens, 211 aperture, 212 imaging device, 213 Electrical contact, 214 Body drive control device, 215 Liquid crystal display element drive circuit, 216 Liquid crystal display element, 217 Eyepiece lens, 219 Memory card, 310 Imaging pixel, 311, 313, 314 Focus detection pixel, 320 line memory, 330 Output times Path, 501 signal line, 502 vertical scanning circuit, 504 reset circuit, 522 horizontal scanning circuit

Claims (14)

A first microlens, a color filter that transmits light in a specific wavelength region in visible light, a first photoelectric conversion unit that receives light via the first microlens and the color filter, and the first A first signal output unit that amplifies and outputs an electrical signal photoelectrically converted by the photoelectric conversion means, and generates a plurality of types of spectral sensitivity characteristics that generate output signals corresponding to an optical image formed by the optical system. A plurality of imaging pixels;
A second microlens, a second photoelectric conversion unit that receives light via the second microlens, and a second signal output unit that amplifies and outputs an electrical signal photoelectrically converted by the second photoelectric conversion unit; A plurality of focus detection pixels that generate a pair of output signals corresponding to a pair of images formed by a pair of light beams passing through the optical system;
Adjusting means for adjusting the signal level of the focus detection pixel and the signal level of the imaging element under the same light receiving condition so that the signal level of the focus detection pixel is smaller than the signal level of the imaging pixel;
The imaging device, wherein the plurality of imaging pixels and the plurality of focus detection pixels are two-dimensionally arranged. The imaging device according to claim 1,
The image pickup device according to claim 1, wherein the adjusting unit is a dimming unit that reduces the amount of light incident on the second photoelectric conversion unit. The imaging device according to claim 2,
The dimming means is a neutral density filter disposed between the second microlens and the second photoelectric conversion means,
The image-capturing element, wherein the neutral density filter transmits light in almost all wavelength regions of visible light. The imaging device according to claim 2,
The dimming means is a light shielding member disposed between the second microlens and the second photoelectric conversion means,
The image-capturing element, wherein the light-shielding member shields part of a light beam incident on the second photoelectric conversion means. The imaging device according to claim 2,
The dimming means is a beam splitter provided in the focus detection pixel,
The image pickup device, wherein the beam splitter deflects a part of a light beam incident on the second photoelectric conversion unit to a part other than the second photoelectric conversion unit. The imaging device according to claim 1,
The adjusting means determines the amplification level of the second signal output unit to be smaller than the amplification level of the first signal output unit, so that the signal level of the focus detection pixel and the signal of the imaging pixel in the same light receiving condition An imaging device characterized by adjusting a level. The imaging device according to claim 1,
The adjusting means determines the quantum efficiency of the second photoelectric conversion means to be smaller than the quantum efficiency of the first photoelectric conversion means, whereby the signal level of the focus detection pixel and the signal of the imaging pixel under the same light receiving condition An imaging device characterized by adjusting a level. The imaging device according to claim 1,
The image pickup device according to claim 1, wherein the adjusting means is charge accumulation time control means for determining a charge accumulation time of the second photoelectric conversion means to be smaller than a charge accumulation time of the first photoelectric conversion means. The imaging device according to claim 1,
The adjustment unit is configured such that the signal level of the focus detection pixel is approximately 75% or less of the signal level of the imaging pixel with respect to the signal level of the focus detection pixel and the signal level of the imaging pixel in the same light receiving condition. An image pickup device that is adjusted to the above. The imaging device according to claim 1,
The image pickup element and the focus detection pixel are arranged in a square lattice shape, and the opening shape of the first microlens and the opening shape of the second microlens are the same. The imaging device according to claim 10,
An imaging device, wherein the opening shape of the first microlens and the second microlens is a rectangle. The imaging device according to claim 1,
The plurality of types of imaging pixels are a red pixel, a green pixel, and a blue pixel, and are arranged in a Bayer array. The imaging device according to claim 1,
Image generating means for generating image data relating to the optical image based on a signal output of the imaging pixel;
An imaging apparatus comprising: a focus detection unit that detects a focus adjustment state of the optical system based on a signal output of the focus detection pixel. The imaging device according to claim 13.
The image generation means interpolates and generates pixel data relating to the optical image formed on the focus detection pixel by interpolating data of the focus detection pixel and data of the imaging pixels around the focus detection pixel. An imaging device comprising:

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