JP2015161727A - Imaging element and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a resolution from deteriorating while keeping interpolation precision high.SOLUTION: A solid state imaging element 1 including a plurality of pixels 3A for imaging and a plurality of (four kinds of) pixels 2L, 2R, 2T, and 2B for focus detection (for AF) which perform a focus detecting operation using image light from a subject, a two-dimensional pixel arrangement includes a Bayer color array of a plurality of two pixels by two pixels comprising the pixels 2L, 2R, 2T, and 2B for AF, and when interpolation processing is performed in which the pixel 2L, 2R, 2T, or 2B for AF in the Bayer color array of two pixels by two pixels is defined as a defective pixel to be corrected, only a pixel 3A for imaging among the pixels 2L, 2R, 2T, and 2B for AF and the pixel 3A for imaging is arranged as a pixel of the same color with the defective pixel to be corrected (one of the pixels 2L, 2R, 2T, and 2B for AF) in a region of five pixels by five pixels including the defective pixels to be corrected (pixel 2L, 2R, 2T, or 2B for AF) in the center respectively and in a region outside the Bayer color array of two pixels by two pixels of the parenthesized pixels.

Description

  The present invention relates to an image pickup device that performs a focus detection operation using a plurality of focus detection pixels and photoelectrically converts image light from a subject using the plurality of image pickup pixels, for example, a digital video camera and a digital still It is used in the imaging section of electronic information equipment such as digital cameras such as cameras, image input cameras such as surveillance cameras, scanner devices, facsimile devices, television telephone devices, and mobile phone devices with cameras. It is related with the imaging device used as.

  Recently, in an imaging apparatus such as a camera, it is necessary to detect a focus adjustment state of a photographing lens in order to realize automatic focus adjustment. Conventionally, a focus detection element has been provided separately from the imaging element. However, in this case, the cost is increased and the apparatus is increased in size by the focus detection element and the focus detection optical system that guides light to the focus detection element.

  Therefore, in recent years, for example, Patent Document 1 proposes an imaging device configured to be used as a focus detection element while adopting a so-called pupil division phase difference method as a focus detection method. In the pupil division phase difference method, the light beam passing through the photographing lens is divided into pupils to form a pair of divided images, and the pattern shift (phase shift amount) is detected to detect the defocus amount of the photographing lens. Yes.

  FIG. 12 is a schematic plan view schematically showing an effective pixel region of a conventional solid-state imaging device disclosed in Patent Document 1. As shown in FIG.

  As shown in FIG. 12, the effective pixel region 101 of the solid-state imaging device 100 includes cross-shaped focus detection regions 102 and 103 disposed at the center, focus detection regions 104 and 105 disposed opposite to the left and right sides, Focus detection areas 106 and 107 arranged on both upper and lower sides are provided. Note that an X axis, a Y axis, and a Z axis that are orthogonal to each other are defined. A plane parallel to the XY plane coincides with the imaging surface (light receiving surface; effective pixel region 101) of the solid-state imaging device 100. The arrangement in the X-axis direction is a row, and the arrangement in the Y-axis direction is a column. Further, the incident light is incident from the front side of the sheet of FIG.

  FIG. 13 is a schematic enlarged plan view in which the vicinity of the intersection of the focus detection areas 102 and 103 in FIG. 12 is enlarged.

  In FIG. 13, each pixel is provided with a color filter, but if the color filter provided in the pixel is classified without distinguishing colors, the solid-state imaging device 100 includes one type of imaging pixel 20 </ b> A, Four types of AF pixels 110L, 110R, 110T, and 110B are provided.

  The focus detection regions 102 to 107 include AF pixels 110 </ b> L and 110 </ b> R that selectively receive a light beam from an exit pupil that is decentered left and right from the center of the exit pupil of the optical system and output a signal obtained by photoelectric conversion. , AF pixels 110T and 110B for selectively receiving a light beam from an exit pupil decentered vertically from the center of the exit pupil of the optical system and outputting a signal obtained by photoelectric conversion, and a pixel block, All 2 × 2 pixels (4 pixels) are provided with color filters of the same color, and each color information is output.

  Thereby, in the AF detection, phase difference detection by the vertical edge component by the AF pixels 110L and 110R and phase difference detection by the horizontal edge component by the AF pixels 110T and 110B can be performed. When generating a recorded image, the AF pixels 110R, 110L, 110T, and 110B are replaced with 2 × 2 pixels (4 pixels) provided with a color filter of the same color, thereby improving the interpolation accuracy.

  FIG. 14A is a schematic diagram illustrating the types of focus detection (AF) pixels, and FIG. 14B illustrates the eccentricity of the light beam as viewed from the lens surface for each AF pixel in FIG. 14A. FIG. 14C is a schematic plan view illustrating a decentering of the light flux on the lens surface by shielding the incident light beam from the subject and the sensor surface.

  As shown in FIG. 14A, the AF pixel 110L in which the light shielding region 111 is on the right half and the incident light is incident on the left half, and the light shielding region 111 is on the left half and the incident light is incident on the right half. The AF pixel 110R, the AF pixel 110T in which the light shielding region 111 is in the lower half and the incident light is incident on the upper half, and the AF pixel 11B in which the light shielding region 111 is in the upper half and the incident light is incident on the lower half And four types of AF pixels. It is a Bayer color arrangement for every four pixels of the same color. The four pixels of the same color include AF pixels 110L and 110R or AF pixels 110T and 110B.

  In FIG. 14B, light is incident on the lens 112 on the AF pixel 110L, and light is incident on the right half incident light region 113 reaching the AF pixel 110L and the lens 112 on the AF pixel 110R. Light is incident on the left half light region 113 that reaches the AF pixel 110R and the lens 112 on the pixel 110T, and light enters the lower half light region 113 that reaches the pixel 110T and the lens 112 on the AF pixel 110B. , And the upper half incident light region 113 reaching the AF pixel 110B. For example, in the right half incident light region 113 reaching the AF pixel 110L, the right half of the AF pixel 110L is covered with a light-shielding film, so that the light incident on the right half of the incident light region 113 of the lens 112 is diagonally opposite. This is incident on the left half AF pixel 110L on the left side.

  As shown in FIG. 14C, since the light shielding film 114 is disposed on the right half of the sensor surface of the AF pixel 110L, the light enters the incident light region 113 on the right half of the lens 112 from the subject 115. Light enters the left half of the AF pixel 110L on the diagonally opposite side.

  FIG. 15A is a plan view showing the pixel arrangement state in the central portion of the effective pixel region at the time of reading all pixels, and FIGS. 15B and 15C are the pixel arrangement state at the time of vertical 1/2 thinning readout. FIG.

  From the pixel array in the central portion of the effective pixel region at the time of reading all the pixels in FIG. 15A, rows having four pixels as one unit are alternately thinned out in the vertical direction as shown in FIG. ), A combined pixel array at the time of vertical ½ thinning readout can be obtained.

Japanese Patent No. 5040458

  In the above-described conventional configuration disclosed in Patent Document 1, all 2 × 2 pixels (4 pixel units) are provided with color filters of the same color in the pixel block, and each pixel block has a single color. Color information is output. In AF detection, AF operation can be performed by performing phase difference detection by vertical edge components by AF pixels 110L and 110R and phase difference detection by horizontal edge components by AF pixels 110T and 110B. When a recorded image is generated, the pair of AF pixels 110R and 110L or the pair of AF pixels 110T and 110B is any of 2 × 2 pixels provided with a color filter of the same color in units of four pixels. Interpolation accuracy is improved by replacing with such imaging pixels.

  However, in this pixel block, color filters of the same color are used for all 2 pixels × 2 pixels (4 pixel units). A pair of AF pixels 110L and 110R for AF detection receives and photoelectrically converts a light beam from an exit pupil which is present in a 2 pixel × 2 pixel block using a color filter of the same color and is not substantially eccentric. This is a Bayer array in units of four pixel blocks on the assumption that the pixel 110A is replaced with a normal imaging pixel 110A. For this reason, by replacing the pair of AF pixels 110L and 110R with the imaging pixels 110A in the vicinity of the same color filter within the 4-pixel unit, the entire effective pixel area can be made the same as the arrangement of the imaging pixels 110A. Although the accuracy of the interpolation is improved, there is a problem that when a recording image for recording is created, only a resolution of 1/4 of the number of solid-state image sensors can be obtained.

  The present invention solves the above-described conventional problems, and an object thereof is to provide an imaging device capable of preventing resolution degradation while maintaining high interpolation accuracy, and an imaging device using the imaging device. And

  The imaging device of the present invention includes a plurality of imaging pixels that photoelectrically convert incident light to generate signal charges, and a plurality of focus detection pixels that perform a focus detection operation using image light from a subject. In the image pickup device, the two-dimensional pixel arrangement includes a predetermined color array of a plurality of 2 pixels × 2 pixels configured by the focus detection pixels, and the focus detection within the predetermined color array of 2 pixels × 2 pixels is performed. When the target pixel is a defective pixel to be corrected, the correction target defect is within a region of 5 pixels × 5 pixels centered on the defective pixel to be corrected and outside the predetermined color array of 2 pixels × 2 pixels. In the same color pixel as the pixel, only the image pickup pixel is arranged, and thereby the above object is achieved.

  Preferably, the two-dimensional pixel arrangement in the imaging device of the present invention includes a predetermined color array of a plurality of 2 pixels × 2 pixels configured by the imaging pixels and a plurality of the focus detection pixels. The predetermined color arrangement of 2 pixels × 2 pixels is uniformly arranged at equal intervals in the two-dimensional pixel arrangement.

  Furthermore, it is preferable that the predetermined color arrangement of a plurality of 2 pixels × 2 pixels configured by focus detection pixels in the image sensor of the present invention has at least two columns in the horizontal direction and at least two rows in the vertical direction. They are arranged with pixels in between.

  Further preferably, in the image pickup device of the present invention, even in the two-dimensional pixel arrangement after the preview drive, the predetermined color arrangement of a plurality of 2 pixels × 2 pixels constituted by the focus detection pixels is a horizontal The imaging pixels are arranged with at least two columns in the direction and at least two rows in the vertical direction.

  Further preferably, the preview driving in the image sensor of the present invention is vertical thinning driving.

  Further preferably, the predetermined color arrangement of 2 pixels × 2 pixels in the image sensor of the present invention is a Bayer color arrangement of 2 pixels × 2 pixels.

  The image pickup apparatus of the present invention uses the image pickup device of the present invention as an image input device, and thereby achieves the above object.

  With the above configuration, the operation of the present invention will be described below.

  In the present invention, imaging including a plurality of imaging pixels that photoelectrically convert incident light to generate a signal charge and a plurality of focus detection pixels for performing a focus detection operation using image light from a subject. In the element, the two-dimensional pixel arrangement includes a predetermined color array of a plurality of 2 pixels × 2 pixels composed of focus detection pixels, and the focus detection pixels in the predetermined color array of 2 pixels × 2 pixels are to be corrected. In the case of a defective pixel, the same color pixel as the correction target defective pixel is used for imaging in a region of 5 pixels × 5 pixels centered on the correction target defective pixel and outside the predetermined color array of 2 pixels × 2 pixels. Only the pixels are arranged.

  This makes it possible to prevent resolution degradation while maintaining interpolation accuracy.

  As described above, according to the present invention, resolution degradation can be prevented while maintaining interpolation accuracy.

It is a partial schematic plan view which shows typically the pixel structural example of 10 rows 16 columns of the solid-state image sensor in Embodiment 1 of this invention. (A) is a schematic diagram showing the types of AF pixels, (b) is a schematic plan view for explaining the eccentricity of a light beam as viewed from the lens surface for each AF pixel in (a), and (c) is from a subject. It is a longitudinal cross-sectional schematic diagram explaining the eccentricity of the light beam in a lens surface by the light-shielding of the incident light beam and the sensor surface. (A) is a longitudinal sectional view for explaining an optical path from the subject 7 to one AF pixel, and (b) is a plan view when the lower side is viewed from the microlens of (a). (A) is a longitudinal sectional view for explaining an optical path from the subject 7 to one AF pixel, and (b) is a plan view when the lower side is viewed from the microlens of (a). (A) is a plan view when the one AF pixel is viewed from the microlens, and (b) is a plan view when the one AF pixel is viewed from the microlens. It is a figure for demonstrating AF operation | movement using a pair of AF pixel. (A)-(d) is a pixel top view for demonstrating the case where each AF pixel in the center block for AF of FIG. 1 is replaced with the surrounding some imaging pixel. (A)-(h) is a top view for demonstrating the kind of four AF pixel arrangement | positioning in the center block for AF in the 4-pixel unit of FIG. FIG. 9A is a pixel arrangement diagram when thinning readout driving is performed with vertical 1/2 thinning (no horizontal thinning) in the solid-state imaging device according to the second embodiment of the present invention, and FIG. FIG. 9B is a pixel arrangement diagram for explaining thinning out at the time of vertical 1/2 pixel readout, and FIG. 9C is a pixel composition diagram after vertical 1/2 pixel readout. FIG. 9 is a pixel layout diagram when thinning readout driving is performed with vertical 1/4 thinning (no horizontal thinning) in another solid-state imaging device according to Embodiment 2 of the present invention, and (a) is a pixel layout diagram when all pixels are read. (B) is a pixel arrangement diagram for explaining thinning out at the time of vertical 1/4 pixel reading, and (c) is a pixel composition diagram after vertical 1/4 pixel reading. It is a block diagram which shows the principal part structural example of the high-speed AF camera system as an imaging device of Embodiment 3 of this invention. It is a schematic plan view which shows typically the effective pixel area | region of the conventional solid-state image sensor currently disclosed by patent document 1. FIG. FIG. 13 is a schematic enlarged plan view in which the vicinity of the intersection of the focus detection area in FIG. 12 is enlarged. Schematic diagram showing the types of focus detection (AF) pixels, (b) is a schematic plan view for explaining the eccentricity of the light beam seen from the lens surface for each AF pixel in (a), and (c) is the subject. It is a longitudinal cross-sectional schematic diagram explaining the eccentricity of the light beam in a lens surface by the light-shielding of the incident light from and the sensor surface. (A) is a plan view showing a pixel arrangement state in the central portion of the effective pixel region at the time of reading all pixels, and (b) and (c) are plan views showing a central pixel arrangement state at the time of vertical 1/2 thinning readout. is there.

  Hereinafter, Embodiments 1 and 2 of the AF pixel array of the image sensor of the present invention and Embodiment 3 of an image pickup apparatus such as a camera using Embodiments 1 and 2 of the AF pixel array of the image sensor will be described. Details will be described with reference to FIG. In addition, each thickness, length, etc. of the structural member in each figure are not limited to the structure to illustrate from a viewpoint on drawing preparation.

(Embodiment 1)
FIG. 1 is a partial schematic plan view schematically showing a 10 × 16 pixel configuration example of the solid-state imaging device according to Embodiment 1 of the present invention.

  In FIG. 1, the solid-state imaging device 1 of Embodiment 1 includes a green color (G; indicated by a white background without dots) in one diagonal direction, a green color (G), and a red color (R; , Indicated by dense dots), blue (B; indicated by sparse dots in the figure), one block (2 rows × 2 columns; 2 × 2) of 4 pixel units in a Bayer array (Bayer color array) in which each color filter is arranged ) Is configured. An AF central block 2 (2 rows × 2 columns; 2 × 2) in which four types of focus detection (AF) pixels 2R, 2L, 2T, and 2B are arranged, and four imaging pixels 3A around it. And 8 surrounding blocks 30 in which 8 arranged 1 block (2 rows × 2 columns; 2 × 2) is arranged. One imaging block (2 rows × 2 columns; 2 × 2) is interposed between adjacent AF central blocks 2. One imaging block is shared as each peripheral block of each AF central block 2. In other words, the AF central block 2 is arranged with two rows or two columns (one block) in between. As a result, the AF central blocks 2 are discretely arranged every other block, evenly on the sensor surface of the effective pixel region in the matrix direction.

  In one block every 4 pixel units (AF central block 2; 2 × 2), a green (G) AF pixel 2L is arranged at the upper left, and a blue (B) AF pixel 2R is arranged at the lower left. A red (R) AF pixel 2T is arranged at the upper right, and a green (G) AF pixel 2B is arranged at the lower right to form a Bayer color arrangement.

  The edge pattern in the vertical direction can be detected by the pair of AF pixels 2L and 2R, and the edge pattern in the horizontal direction can be detected by the pair of AF pixels 2T and 2B. These four types of AF pixels 2L, 2R, 2T, and 2B are collected in the AF central block 2, and one block composed of four imaging pixels 3A is arranged around the AF central block 2 so that interpolation described later is easy. Eight surrounding blocks 30 are provided.

  From the AF pixels 2L and 2R for selectively receiving a light beam from the exit pupil decentered to the left and right from the center of the exit pupil of the optical system and outputting a signal obtained by photoelectric conversion, and from the center of the exit pupil of the optical system It has AF pixels 2T and 2B that selectively receive light beams from the vertically exiting exit pupil and output signals obtained by photoelectric conversion. Thus, for AF detection, phase difference detection by the vertical edge component by the pair of AF detection pixels 2L and 2R and phase difference detection by the horizontal edge component by the pair of AF detection pixels 2T and 2B are performed. In addition, when generating a recorded image, the AF pixels 110R, 110L, 110T, and 110B are replaced with four or more pixels that are provided with a color filter of the same color in the immediate vicinity so that Patent Document 1 The interpolation accuracy can be equal to or better than.

  2A is a schematic diagram showing the types of AF pixels, FIG. 2B is a schematic plan view for explaining the decentering of the light beam as viewed from the lens surface for each AF pixel in FIG. 2A, and FIG. (C) is a longitudinal cross-sectional schematic diagram explaining the eccentricity of the light beam in a lens surface by the light ray from a to-be-photographed object and the light shielding of the sensor surface.

  As shown in FIG. 2A, an AF pixel 2L into which incident light (white without dots; green) is incident from an opening area 22 in the left half, and the light shielding area 21 is in the right half. The AF pixel 2R in which incident light (sparse dots; blue) is incident from the right half opening area 22 and the light shielding area 21 is in the lower half and incident light (dense from the upper half opening area 22). The four types of pixels, the AF pixel 2T on which dots (red) are incident, and the AF pixel 2B on which the light shielding region 21 is located in the upper half and the incident light is incident from the lower half opening region 22 are in units of four pixels. Each (2 rows × 2 columns; 2 × 2) is provided in the AF central block 2. In the Bayer color arrangement, for example, an AF pixel 2L using a green color filter and an AF pixel 2B using a green color filter are arranged in one diagonal direction, and red in the other diagonal direction. The AF pixel 2T using the color filter and the AF pixel 2R using the blue color filter are arranged.

  In FIG. 2B, in the leftmost microlens 4, light is incident on the microlens 4 on the AF pixel 2 </ b> L, and light in the incident light region 5 in the right half of the microlens 4 is in the left half opening region 22. Through to the AF pixel 2L. In the second microlens 4 from the left, light enters the microlens 4 on the AF pixel 2R, and the light in the left half light region 5 of the microlens 4 passes through the right half opening region 22 to the pixel 2R. It reaches. Further, in the third microlens 4 from the left, light enters the microlens 4 on the AF pixel 2T, and the light in the lower half light region 5 of the microlens 4 passes through the upper half opening region 22, and the AF pixel. 2T. Furthermore, in the fourth microlens 4 from the left, light enters the microlens 4 on the AF pixel 2B, and the light in the upper half light area 5 of the microlens 4 passes through the lower half opening area 22 to be the AF pixel. Up to 2B.

  As shown in FIG. 2C, since the light shielding film 6 is disposed on the right half of the sensor surface of the AF pixel 2L, the light enters the incident light region 5 on the right half of the microlens 4 from the subject 7. The incident light enters the left half of the AF pixel 2L on the diagonally opposite side through the opening region 22.

  FIG. 3A is a longitudinal sectional view for explaining an optical path from the subject 7 to the AF pixel 2L, and FIG. 3B is a view when the lower side is viewed from the microlens 4 in FIG. FIG.

  As shown in FIGS. 3A and 3B, the light from the subject 7 is further condensed by the microlens 4 for each pixel through the imaging lens 8 and is centered through the green (G) color filter 9. The light enters the left half of the sensor surface of the AF pixel 2L made of a photodiode through the opening region 22 on the left half of the line CL. The right half of the center line CL is a light shielding film 6 and the right half of the sensor surface of the AF pixel 2L is a light shielding region 21. Note that E indicates a chief ray due to metal shading. F indicates the exit pupil position due to metal shading. G indicates a region where light is shielded by metal shading.

  4A is a longitudinal sectional view for explaining an optical path from the subject 7 to the AF pixel 2R, and FIG. 4B is a view when the lower side is viewed from the microlens 4 of FIG. 4A. FIG.

  As shown in FIGS. 4A and 4B, the light from the subject 7 is further condensed by the microlens 4 for each pixel through the imaging lens 8 and is centered through the blue (B) color filter 9. The light enters the right half of the sensor surface of the AF pixel 2R made of a photodiode through the opening region 22 on the right half of the line CL. The left half of the center line CL is a light shielding film 6, and the left half of the sensor surface of the AF pixel 2 </ b> R is a light shielding region 21. Note that E indicates a chief ray due to metal shading. F indicates the exit pupil position due to metal shading. G indicates a region where light is shielded by metal shading.

  FIG. 5A is a plan view when the AF pixel 2B is viewed from the micro lens 4, and FIG. 5B is a plan view when the AF pixel 2T is viewed from the micro lens 4. FIG. is there.

  As shown in FIG. 5A, the light from the subject 7 is further condensed by the microlens 4 for each pixel through the imaging lens 8 and passes through the green (G) color filter 9 to the lower half of the center line CL. Is incident on the lower half of the sensor surface of the AF pixel 2B made of a photodiode. The upper half of the center line CL is a light shielding film 6, and the upper half of the sensor surface of the AF pixel 2 </ b> B is a light shielding region 21.

  As shown in FIG. 5B, the light from the subject 7 is further condensed by the microlens 4 for each pixel through the imaging lens 8 and passes through the red (R) color filter 9 to the upper half of the center line CL. The light is incident on the upper half of the sensor surface of the AF pixel 2T made of a photodiode through the opening region 22. The lower half of the center line CL is a light shielding film 6, and the lower half of the sensor surface of the AF pixel 2T is a light shielding region 21.

  Here, an AF operation using the AF pixels 2L, 2R, 2T, and 2B will be described with reference to FIG.

  FIG. 6 is a diagram for explaining an AF operation using a pair of AF pixels 2L and 2R.

  As shown in FIG. 6, by comparing the signal amount of the AF pixel 2L at the out-of-focus position with the signal amount of the AF pixel 2R, the solid-state image sensor 10 (corresponding to the solid-state image sensor 1) is effective. The amount of movement f (d) (μm) of the imaging lens 8 from the inter-pixel distance (phase difference d (μm)) in which the signal amount between the AF pixels 2L and 2R in the pixel region matches is obtained. Thus, AF control can be performed.

  If the angle of the pupil position viewed from the solid-state imaging device 10 is θ, the moving amount f (d) (μm) of the imaging lens 8 can be set to 2 × d / tan θ (μm).

  Next, AF pixel defect correction for interpolating the AF pixels 2L, 2R, 2T, and 2B as the imaging pixels 2A will be described.

  The AF pixels 2L, 2R, 2T, 2B in the AF central block 2 are arranged in a 2 pixel × 2 pixel Bayer color array, and the AF pixels 2L, 2R, 2T, 2B are used as defective pixels to be corrected. Sometimes, the AF pixels 2L, 2R, 2T, and 2B are not arranged in the 5 pixel × 5 pixel region in the peripheral 8 block 30 centering on the defective pixel to be corrected, and are not substantially decentered. A normal imaging pixel 3A that receives a light beam from the exit pupil and performs photoelectric conversion is disposed.

  The imaging pixels 3A of the same color that can be used to correct AF pixel defects (pixels that are not imaged) are in the surrounding 8 blocks 30 with the correction target defective pixels (AF pixels 2L, 2R, 2T, and 2B) as centers. There are 8 pixels in the left, right, top, bottom, right diagonal and left diagonal directions. As an example of the correction method shown in FIGS. 7A to 7D, the correction target defective pixels (AF pixels 2L, 2R, 2T, and 2B) are set to 8 pixels of the same color in the peripheral 8 block 30. It can be replaced with the average value of the data.

  FIGS. 7A to 7D are pixel plan views for explaining a case where the AF pixels 2L, 2R, 2T, and 2B in the AF central block 2 of FIG. 1 are replaced with the imaging pixels 2A. is there.

  As shown in FIG. 7A, the blue AF pixel 2R located at the lower left of the AF central block 2 in units of 4 pixels is replaced with the blue peripheral 8 pixels in the 5 pixels × 5 pixel region in the peripheral 8 block 3. The average value is taken from the image data of the imaging pixels 3A (left, right, up, down, right diagonal and left diagonal directions) and interpolated as image data of the AF pixel 2R.

  As shown in FIG. 7B, the red color in the 5 pixels × 5 pixel region in the peripheral 8 block 3 centering on the red AF pixel 2T located at the upper right of the AF central block 2 in units of 4 pixels. The average value is taken from the image data of the imaging pixels 3A of the surrounding 8 pixels (right and left, up and down, right diagonal and left diagonal directions), and is interpolated as image data of the AF pixel 2T.

  As shown in FIG. 7C, the green pixels in the 5 pixel × 5 pixel region in the peripheral 8 block 3 centering on the green AF pixel 2L located at the upper left of the AF central block 2 in units of 4 pixels. The average value is taken from the image data of the imaging pixels 3A of the surrounding 8 pixels (left and right, up and down, right diagonal and left diagonal directions), and is interpolated as image data of the AF pixel 2L.

  As shown in FIG. 7D, the green color in the 5 pixels × 5 pixel area in the peripheral 8 block 3 centering on the green AF pixel 2B located at the lower right of the AF central block 2 in units of 4 pixels. Are averaged from the image data of the imaging pixels 3A of the 8 pixels around (right, left, up, down, diagonally right and diagonally left) and interpolated as image data of the AF pixel 2B.

  As a result, the Bayer color arrangement in units of one pixel and the AF pixels 2L, 2R, 2T, and 2B are arranged almost uniformly in the sensor surface (effective pixel area), and the horizontal and vertical edges are arranged. Phase difference detection by pattern is possible (equivalent to or better than Patent Document 1), and the same color pixels that can be used for AF pixel defect correction are centered on the correction target defective pixels (AF pixels 2L, 2R, 2T, and 2B). Since there are 8 pixels of 4 pixels or more in the neighborhood 5 pixels × 5 pixels, the resolution is not deteriorated when all the pixels are read, and the interpolation accuracy can be maintained with high accuracy.

  As described above, according to the first embodiment, a plurality of imaging pixels 3A that photoelectrically convert incident light to generate signal charges and a plurality (here, a focus detection operation using image light from a subject). In the solid-state imaging device 1 provided with four types of focus detection (AF) pixels 2L, 2R, 2T, and 2B, the two-dimensional pixel arrangement includes AF pixels 2L, 2R, 2T, and 2B. When the interpolation processing is performed on the AF pixels 2L, 2R, 2T, and 2B in the 2 pixel × 2 pixel Bayer color array as defective pixels to be corrected, In the area of 5 pixels × 5 pixels centered on each of the defect pixels to be corrected (AF pixels 2L, 2R, 2T, 2B), and in the area outside the Bayer color array of 2 pixels × 2 pixels, Pixels (AF pixels 2L, 2R, 2 Any) and AF pixel 2L in the same color pixels 2B, 2R, 2T, only imaging pixels 3A of 2B and imaging pixels 3A is arranged.

  Thus, the AF pixels 2R, 2L, 2T, and 2B are arranged in the Bayer color arrangement in units of one pixel, and the AF pixels are evenly or substantially evenly arranged in the sensor surface of the solid-state image pickup device 1 so that the horizontal and vertical directions are arranged. The same color pixel that can detect the phase difference by the direction edge pattern (equivalent to Patent Document 1) and can be used for AF pixel defect correction for the AF pixels 2R, 2L, 2T, and 2B is used for AF. Since there are 8 pixels of 4 pixels or more in the vicinity 5 pixels x 5 pixels centering on the defective pixel to be corrected of the pixels 2R, 2L, 2T, and 2B, there is no deterioration in resolution and high interpolation accuracy when reading all pixels Can be held in. In this way, resolution degradation can be prevented while maintaining high interpolation accuracy.

  In the first embodiment, as shown in FIG. 8A, in the AF central block 2 for each four-pixel unit, the green (G) AF pixel 2L is arranged at the upper left, and the blue ( B) AF pixel 2R is arranged, red (R) AF pixel 2T is arranged at the upper right, and green (G) AF pixel 2B is arranged at the lower right to form a 4-pixel unit of the Bayer color array. Although the configuration has been described, the present invention is not limited thereto, and other arrangements of AF pixels 2R, 2L, 2T, and 2B as shown in FIGS. 8B to 8H may be used.

  FIGS. 8A to 8H are plan views for explaining types of arrangement of AF pixels 2R, 2L, 2T, and 2B in the AF central block 2 in the 4-pixel unit of FIG. is there.

  In FIG. 8B, in the AF central block 2 for each four-pixel unit in the Bayer color array, the green (G) AF pixel 2R is arranged at the upper left, and the blue (B) AF pixel 2L at the lower left. Are arranged, the red (R) AF pixel 2B is arranged at the upper right, and the green (G) AF pixel 2T is arranged at the lower right.

  In FIG. 8C, in the AF central block 2 for each four-pixel unit in the Bayer color array, the green (G) AF pixel 2T is arranged at the upper left, and the blue (B) AF pixel 2B at the lower left. Are arranged, the red (R) AF pixel 2L is arranged at the upper right, and the green (G) AF pixel 2R is arranged at the lower right.

  In FIG. 8D, in the AF central block 2 for each four-pixel unit in the Bayer color array, the green (G) AF pixel 2B is arranged at the upper left, and the blue (B) AF pixel 2T at the lower left. Are arranged, the red (R) AF pixel 2R is arranged at the upper right, and the green (G) AF pixel 2L is arranged at the lower right.

  In FIG. 8E, in the AF central block 2 for each four-pixel unit in the Bayer color array, the green (G) AF pixel 2R is arranged at the upper left, and the blue (B) AF pixel 2B at the lower left. Are arranged, a red (R) AF pixel 2L is arranged at the upper right, and a green (G) AF pixel 2T is arranged at the lower right.

  In FIG. 8F, in the AF central block 2 for each four-pixel unit in the Bayer color array, the green (G) AF pixel 2L is arranged at the upper left, and the blue (B) AF pixel 2T at the lower left. Are arranged, the red (R) AF pixel 2R is arranged at the upper right, and the green (G) AF pixel 2B is arranged at the lower right.

  In FIG. 8G, in the AF central block 2 for each four-pixel unit in the Bayer color array, the green (G) AF pixel 2R is arranged at the upper left, and the blue (B) AF pixel 2B at the lower left. Are arranged, the red (R) AF pixel 2T is arranged at the upper right, and the green (G) AF pixel 2L is arranged at the lower right.

  In FIG. 8H, in the AF central block 2 for each four-pixel unit in the Bayer color array, the green (G) AF pixel 2L is arranged at the upper left, and the blue (B) AF pixel 2T at the lower left. Are arranged, the red (R) AF pixel 2B is arranged at the upper right, and the green (G) AF pixel 2R is arranged at the lower right.

  In the first embodiment, one imaging block (2 rows and 2 columns; 2 × 2) is provided between adjacent AF central blocks 2, and the one imaging block is provided on each AF on both sides. The AF central block 2 is shared by each AF central block 2 as surrounding blocks, and the AF central block 2 is arranged in two rows or two columns (one block) in the horizontal and vertical directions. However, the present invention is not limited to this, and the AF central block 2 may be arranged every n (n is a plurality) blocks.

  That is, a plurality of imaging blocks (2 rows × 2 columns; 2 × 2) are provided between adjacent AF central blocks 2, and the plurality of imaging blocks correspond to the AF central blocks 2 on both sides thereof. Each of the AF central blocks 2 is shared with each other as a peripheral block. The AF central block 2 is arranged every n blocks in the horizontal direction and the vertical direction. As a result, the AF central block 2 is discretely and evenly spaced every n blocks in the horizontal and vertical directions. Further, 1 or n blocks interposed depending on the horizontal direction and the vertical direction may have different numbers of blocks such as m1 blocks and m2 blocks.

  In short, the Bayer color arrangement of a plurality of 2 pixels × 2 pixels composed of four types of AF pixels 2L, 2R, 2T, and 2B has at least two columns in the horizontal direction and at least two rows in the vertical direction. 3A is placed in between.

  In the second embodiment, even in the two-dimensional pixel arrangement after the preview driving, a plurality of 2 pixels × 2 pixels Bayer color array composed of four types of AF pixels 2L, 2R, 2T, and 2B Will describe a case where imaging pixels 3A are arranged with at least two columns in the horizontal direction and at least two rows in the vertical direction.

(Embodiment 2)
In the first embodiment, the case of reading all pixels using the AF pixel array of the present invention has been described. In the second embodiment, the case of thinning readout driving using the AF pixel array of the present invention will be described. .

  FIG. 9 is a pixel layout diagram when thinning readout driving is performed with vertical ½ thinning (no horizontal thinning) in the solid-state imaging device 1A according to Embodiment 2 of the present invention, and FIG. FIG. 9B is a pixel arrangement diagram for explaining thinning out at the time of vertical 1/2 pixel readout, and FIG. 9C is a pixel composition diagram after the vertical 1/2 pixel readout.

  9A to 9C, in the solid-state imaging device 1A of the second embodiment, the AF central block 2 in which the AF pixels 2R, 2L, 2T, and 2B of the first embodiment are arranged is horizontal. In the direction, two rows of imaging pixels 3A are sequentially arranged, and in the vertical direction, the AF central block 2 is sequentially arranged with six rows of imaging pixels 3A in between, and vertical 1/2 thinning ( Thinning readout drive is possible without horizontal thinning). In this case, even after the pixel arrangement synthesis after the vertical 1/2 pixel reading shown in FIG. 9C, the surrounding 8 blocks 30 are secured around the AF central block 2, and the interpolation operation is the same as in the case of the first embodiment. Similarly, high accuracy can be maintained.

  Since the solid-state imaging device 1A of Embodiment 2 displays a finder image on the liquid crystal screen when performing moving image recording or still image shooting, preview driving (vertical driving) that reduces the number of output pixels from the sensor (solid-state imaging device 1A). Even when ½ decimation readout driving) is performed, the same color pixels that can be used for the AF pixel defect correction described above are corrected target defective pixels (AF pixels 2R, 2L, 2T, Since there are 8 pixels of the same color of 4 pixels or more in the neighborhood of 5 pixels × 5 pixels, each centered on 2B), the resolution is not deteriorated even during preview driving, and the interpolation accuracy can be maintained with high accuracy.

  Next, a case where the thinning rate is different will be further described.

  FIG. 10 is a pixel arrangement diagram when thinning readout driving is performed with vertical 1/4 thinning (no horizontal thinning) in another solid-state imaging device 1B according to Embodiment 2 of the present invention. FIG. FIG. 10B is a pixel layout diagram for explaining thinning out at the time of vertical 1/4 pixel reading, and FIG. 10C is a pixel composition diagram after vertical 1/4 pixel reading. .

  10A to 10C, another solid-state imaging device 1B of the second embodiment is an AF central block 2 in which the AF pixels 2R, 2L, 2T, and 2B of the first embodiment are arranged. Are sequentially arranged with two rows of imaging pixels 3A in the horizontal direction, and the AF central block 2 is sequentially arranged with 14 rows of imaging pixels 3A in the vertical direction, and the vertical 1/4. Thinning readout drive is possible by thinning (no horizontal thinning). In this case, even after the pixel arrangement synthesis after the vertical 1/4 pixel reading shown in FIG. 10C, the surrounding 8 blocks 30 are secured around the AF central block 2, and the interpolation operation is the same as in the case of the first embodiment. Similarly, it can be performed with high accuracy.

  Since the solid-state imaging device 1B of the second embodiment displays a finder image on the liquid crystal screen when performing moving image recording or still image shooting, preview driving (vertical driving) that reduces the number of output pixels from the sensor (solid-state imaging device 1B). Even when 1/4 thinning-out readout driving is performed, the same color pixels that can be used for the AF pixel defect correction described above are corrected target defective pixels (AF pixels 2R, 2L, 2T, Since there are 8 pixels of the same color of 4 pixels or more in the neighborhood of 5 pixels × 5 pixels, each centered on 2B), the resolution is not deteriorated even during preview driving, and the interpolation accuracy can be maintained with high accuracy.

  As described above, according to the second embodiment, even in the two-dimensional pixel arrangement after the preview driving, a plurality of 2 pixels × focus pixels (AF) pixels 2R, 2L, 2T, and 2B × The two-pixel Bayer color array is arranged with at least two columns in the horizontal direction and at least two rows of imaging pixels 3A in the vertical direction. This preview driving is vertical thinning driving (here, vertical 1/2 thinning readout driving or vertical 1/4 thinning readout driving).

  As a result, a preview drive (vertical ½ thinning or vertical ¼) reduces the number of output pixels from the solid-state imaging device 1A or 1B in order to display a finder image on the liquid crystal screen when recording a moving image or taking a still image. Even when performing thinning readout driving), the same color pixels (imaging pixels 3A) that can be used for AF pixel defect correction are corrected target defective pixels (AF pixels 2R, 2L, 2T, Since there are 8 pixels of 4 pixels or more in the neighborhood 5 pixels × 5 pixels each centered on 2B), resolution is not deteriorated even during preview driving, and interpolation accuracy can be maintained with high accuracy. In this way, resolution degradation can be prevented while maintaining high interpolation accuracy.

(Embodiment 3)
In the third embodiment, a high-speed AF camera system of a digital camera as an imaging apparatus using the solid-state imaging device 1, 1A, or 1B of the first and second embodiments will be described.

  FIG. 11 is a block diagram illustrating a configuration example of a main part of a high-speed AF camera system as an imaging apparatus according to the third embodiment of the present invention.

  As shown in FIG. 11, the high-speed AF camera system 50 as the imaging apparatus according to the third embodiment has an imaging lens 8 that is mounted as an optical system that forms an image of a subject, and the focus operation is driven and controlled by moving the imaging lens 8. A lens driving AF driver 51, a solid-state imaging device 1, 1A or 1B for photoelectrically converting image light focused by driving the imaging lens 8, and signals from the solid-state imaging device 1, 1A or 1B. A signal processing unit 52; a memory 53 connected to the signal processing unit 52; a system control unit 54 for driving and controlling the solid-state imaging device 1, 1A or 1B; a recording unit 55 connected to the system control unit 54; An operation SW 56 connected to the control unit 54 and a touch panel connected to the system control unit 54 and capable of position input operation. 57, an LCD drive circuit 58 connected to the system control unit 54, and a display unit 59 connected to the LCD driving circuit 58 (LCD).

  The lens driving AF driver 51 drives the imaging lens 8 to execute a focusing operation.

  The signal processing unit 52 receives an imaging signal and an AF pixel signal from the solid-state imaging device 1, 1A, or 1B, and performs predetermined signal processing.

  The memory 53 stores the imaging signal and the AF pixel signal via the signal processing unit 52.

  The system control unit 54 drives and controls the solid-state imaging device 1, 1 </ b> A or 1 </ b> B, and controls output of pixel signals and AF pixel signals from the solid-state imaging device 1, 1 </ b> A or 1 </ b> B.

  The display unit 59 is configured by an LCD or the like, and a touch panel 57 capable of position input j operation is disposed on the display screen.

  The operation of the above configuration will be described.

  First, an ON operation (shutter operation) is performed by the operation SW 56, and the solid-state imaging device 1, 1A or 1B is driven by a command from the system control unit 54. The solid-state imaging device 1, 1A or 1B The AF pixel signal is output to the signal processing unit 52.

  Next, signals output from the solid-state imaging device 1, 1 </ b> A or 1 </ b> B are an imaging signal that forms a pixel signal indicating a subject image and an AF pixel signal for detecting the focus adjustment state of the imaging lens 8. These imaging signals and AF pixel signals are stored in the memory 53 via the signal processing unit 52.

  Subsequently, the signal amount of the L pixel (AF pixel 2L) of the AF pixel signal stored in the memory 53 and the signal amount of the R pixel (AF pixel 2R) of the AF pixel signal stored in the memory 53 are compared. The amount of movement f of the imaging lens 8 from the inter-pixel distance where the signal amounts between the AF pixel 2L and the AF pixel 2R on the sensor surface of the solid-state imaging device 1, 1A, or 1B coincide with each other to the in-focus position f. (D) is obtained.

  The detection result of the movement amount is transmitted to the system control unit 54 side, the movement amount of the imaging lens 8 is transmitted from the system control unit 54 to the lens driving AF driver 51, and the lens driving AF driver 51 causes the imaging lens 8 to move. The AF operation is performed by driving and moving the movement amount.

  The imaging signal for forming the pixel signal indicating the subject image stored in the memory 53 includes an AF pixel signal. Before performing a signal process for generating a recorded image, a defect correction process using an AF pixel signal included in the imaging signal as a defect is performed. The image signal after the defect correction processing is subjected to signal processing for generating a recorded image, subjected to image compression processing, transmitted to the system control unit 54, and stored in the recording unit 55 from the system control unit 54.

  Therefore, according to the third embodiment, as an imaging apparatus using the solid-state imaging device 1, 1A, or 1B of the first and second embodiments, which can prevent deterioration in resolution while maintaining high interpolation accuracy. A high-speed AF camera system 50 can be obtained.

  In the first to third embodiments, in a two-dimensional and matrix pixel arrangement, a plurality of 2 pixels × 2 pixels Bayer color array composed of four imaging pixels 3A and four AF pixels 2L. , 2R, 2T, 2B, and a plurality of 2 pixels × 2 pixels Bayer color array, the four AF pixels (2 pixels × 2 pixels) are arranged in a Bayer color array (RGB array). However, other predetermined color arrangements may be used. In short, the four AF pixels may have a color arrangement in units of four pixels of 2 pixels × 2 pixels.

  In particular, the image pickup pixel 3A is a predetermined color arrangement in units of four pixels such as a Bayer color arrangement (RGB arrangement), and all four AF pixels (2 pixels × 2 pixels) are the same color (for example, all green). A filter can also be used.

  Further, among the four AF pixels 2L, 2R, 2T, and 2B, different color filters of the same color can be used for the AF pixels 2L and 2R and the AF pixels 2T and 2B, respectively. For example, a green (G) color filter may be used for the AF pixels 2L and 2R, a red (R) color filter may be used for the AF pixels 2T and 2B, and a red (R) may be used for the AF pixels 2L and 2R, for example. ) Color filters, and blue (B) color filters may be used for AF pixels 2T and 2B. For example, blue (B) color filters may be used for AF pixels 2L and 2R, and AF pixels 2T , 2B may be a green (G) color filter. Various other combinations of the color filter colors of the four AF pixels (2 pixels × 2 pixels) (for example, four colors including RGB in addition to RGB) are conceivable.

  In this way, by using different color filters of the same color for the AF pixels 2L, 2R and the AF pixels 2T, 2B among the four AF pixels 2L, 2R, 2T, 2B, the pixel sensitivities are equal (pixel The output signal amount is also equal), and the phase difference calculation accuracy can be improved. The finally recorded image is color-interpolated from the surrounding imaging pixels 3A of the same color.

  As mentioned above, although this invention has been illustrated using preferable Embodiment 1-3 of this invention, this invention should not be limited and limited to this Embodiment 1-3. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and the common general technical knowledge from the description of specific preferred embodiments 1 to 3 of the present invention. Patents, patent applications, and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

  The present invention relates to an imaging device that performs a focus detection operation using a plurality of focus detection pixels, photoelectrically converts image light from a subject using the plurality of imaging pixels, and performs imaging using the plurality of imaging pixels, for example, digital Used for imaging units of electronic information equipment such as digital cameras such as video cameras and digital still cameras, image input cameras such as surveillance cameras, scanner devices, facsimile devices, television telephone devices, and mobile phone devices with cameras. In the field of an imaging apparatus using an element as an image input device, resolution degradation can be prevented while maintaining high interpolation accuracy.

1, 1A, 1B, 10 Solid-state imaging device (imaging device)
2 AF central block 2R, 2L, 2T, 2B Focus detection (AF) pixels 21 Light shielding area 22 Opening area 3 Imaging block 3A Imaging pixels 30 Surrounding 8 blocks 4 Microlens 5 Incident light area 6 Light shielding film 7 Subject 8 Imaging lens 9 Color filter 50 High-speed AF camera system 51 AF driver for lens driving 52 Signal processing unit 53 Memory 54 System control unit 55 Recording unit 56 Operation SW
57 Touch Panel 58 LCD Drive Circuit 59 Display Unit (LCD)

Claims (5)

In an imaging device comprising a plurality of imaging pixels that photoelectrically convert incident light to generate a signal charge, and a plurality of focus detection pixels for performing a focus detection operation using image light from a subject,
The two-dimensional pixel arrangement includes a predetermined color array of a plurality of 2 pixels × 2 pixels constituted by the focus detection pixels, and the focus detection pixels in the predetermined color array of 2 pixels × 2 pixels are to be corrected. When a defective pixel is used, a pixel of the same color as that of the defective pixel to be corrected in a region of 5 pixels × 5 pixels centered on the defective pixel to be corrected and outside the predetermined color array of 2 pixels × 2 pixels. Is an imaging device in which only the imaging pixels are arranged.   The two-dimensional pixel arrangement includes a predetermined color array of a plurality of 2 pixels × 2 pixels configured by the imaging pixels, and a plurality of a predetermined color array of 2 pixels × 2 pixels configured by the focus detection pixels The image pickup device according to claim 1, wherein the two-dimensional pixel arrangement is uniformly arranged at equal intervals.   A predetermined color array of a plurality of 2 pixels × 2 pixels composed of the focus detection pixels is arranged with at least two columns in the horizontal direction and at least two rows of the imaging pixels in the vertical direction. The imaging device according to claim 2.   Even in the two-dimensional pixel arrangement after the preview driving, the predetermined color arrangement of the plurality of 2 pixels × 2 pixels configured by the focus detection pixels is at least two rows in the horizontal direction and at least 2 in the vertical direction. The imaging device according to claim 3, wherein the imaging pixels in a row are disposed with the imaging pixels interposed therebetween.   An imaging device using the imaging device according to claim 1 as an image input device.