JP2015065624A - Imaging device and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging device which equalizes incident light onto two light-receiving areas.SOLUTION: There is provided an imaging device comprising: a plurality of pixels which are arranged along a first direction and second direction and each includes two separated light-receiving areas; and an expansion optical element which is provided on some of the plurality of pixels and expands an area on the light-receiving area irradiated with light incident on the corresponding pixel. The imaging device makes reset timing of a second light-receiving area to be delayed with respect to reset timing for resetting electric charge accumulated in the first light-receiving area, and simultaneously reads out output signals corresponding to electric charge amounts accumulated in the first and second light-receiving areas and subtracts an output signal value of the second light-receiving area from an output signal value of the first light-receiving area to generate a pixel signal of that pixel.

Description

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

There is known an imaging device in which one pixel has two photoelectric conversion elements and outputs a focus detection signal (see, for example, Patent Document 1).
Japanese Patent Application Laid-Open No. 2012-113027

  When two photoelectric conversion elements are used for focus detection, separated light is incident on the two photoelectric conversion elements. On the other hand, in some cases, such as when the output of one photoelectric conversion element is used for correction of the output of the other photoelectric conversion element, it may be preferable that light is equally incident on the two photoelectric conversion elements. However, since the two photoelectric conversion elements cannot be arranged at the same position, the incident light to the two photoelectric conversion elements is not uniform.

  In the first aspect of the present invention, a plurality of pixels having two light receiving regions arranged along the first direction and the second direction and separated from each other, and a part of the plurality of pixels. Provided is an imaging device provided with a magnifying optical element that enlarges an irradiation region in the light receiving region of light incident on a corresponding pixel.

  According to a second aspect of the present invention, there is provided an imaging apparatus including the imaging element according to the first aspect.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

1 is a diagram illustrating an overview of an image sensor 100 according to one embodiment. It is a figure which shows an example of the 1st pixel 202-1. It is a figure which shows an example of the 2nd pixel 202-2 and the 3rd pixel 202-3. 2 is a diagram illustrating an example of a light receiving unit 200. FIG. It is a figure which shows the other process example of the signal processing part. 3 is a diagram illustrating a configuration example of a light receiving unit 200. FIG. FIG. 3 is a diagram illustrating a structural example of a light receiving unit 200. FIG. 3 is a diagram illustrating a structural example of a light receiving unit 200. It is a figure which shows an example of the array conversion process in the signal processing part. It is a figure which shows the example of an arrangement | sequence of the 1st conversion pixel 203-1. It is a figure which shows an example of the array conversion process in the signal processing part. It is a figure which shows the example of an arrangement | sequence of the 2nd conversion pixel 203-2 and the 3rd conversion pixel 203-3. It is a figure which shows the example of an arrangement | sequence of the 1st conversion pixel 203-1, the 2nd conversion pixel 203-2, and the 3rd conversion pixel 203-3. 1 is a perspective view of a micro lens 101. FIG. 2 is a diagram illustrating a planar shape of a microlens 101. FIG. 6 is a diagram illustrating another configuration example of the light receiving unit 200. FIG. It is a figure which shows the example of arrangement | positioning of the transfer transistor TX and the electric charge detection part in the example shown in FIG. 1 is a diagram illustrating an example of a cross section of an image sensor 100. FIG. It is a block diagram which shows the structural example of the imaging device 500 which concerns on one embodiment.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a diagram illustrating an overview of an image sensor 100 according to one embodiment. The image sensor 100 includes a light receiving unit 200 in which a plurality of pixels 202 are arranged, and a signal processing unit 210 that processes a signal from the light receiving unit 200. Each of the plurality of pixels 202 has a light receiving element such as a photodiode, and accumulates electric charges according to the amount of received light. The signal processing unit 210 of this example reads a signal corresponding to the amount of charge accumulated in each pixel 202 and performs a predetermined process.

  The plurality of pixels 202 in this example are arranged in a matrix. That is, the plurality of pixels 202 are arranged along a plurality of rows and a plurality of columns. In the present specification, the row direction is illustrated as the x-axis direction, and the column direction is illustrated as the y-axis direction. The row direction is an example of the first direction, and the column direction is an example of the second direction.

  The plurality of pixels 202 includes a plurality of first pixels 202-1, a plurality of second pixels 202-2, and a plurality of third pixels 202-3. The first pixel 202-1 is a pixel corresponding to the color filter of the first color, the second pixel 202-2 is a pixel corresponding to the color filter of the second color, and the third pixel 202-3. Are pixels corresponding to the color filter of the third color. In this example, the first color is green, the second color is blue, and the third color is red. In this example, the planar shape of each pixel 202 is a quadrangle, and each side of the pixel 202 is inclined 45 degrees with respect to the first direction and the second direction. In a more specific example, the planar shape of each pixel 202 is a square.

  The plurality of first pixels 202-1 are arranged along both the row direction and the column direction. In this example, the vertices of the first pixel 202-1 are arranged so as to be adjacent to each other. With such an arrangement, a region surrounded by the four first pixels 202-1 arranged in proximity is generated. The second pixel 202-2 and the third pixel 202-3 are provided in a region surrounded by the four first pixels 202-1. In this example, the shape of each pixel 202 is the same.

  The second pixels 202-2 are arranged along the column direction. The third pixel 202-3 is also arranged along the column direction. The column of the second pixel 202-2 and the column of the third pixel 202-3 are alternately arranged in the row direction. Further, the column of the second pixel 202-2 and the column of the third pixel 202-3 are arranged so as to be shifted by half a pixel in the column direction with respect to the column of the first pixel 202-1.

  Note that the arrangement of the pixels 202 illustrated in FIG. 1 is an example, and the arrangement of the pixels 202 is not limited to the example of FIG. The pixels 202 may be in an arbitrary arrangement. For example, the array of the pixels 202 may be a so-called Bayer array.

  FIG. 2A is a diagram illustrating an example of the first pixel 202-1. The first pixel 202-1 has two light receiving regions 214 separated. The first light receiving region 214a and the second light receiving region 214b of the first pixel 202-1 are arranged side by side in the row direction. In this example, the two light receiving regions 214 are defined by dividing the region of the first pixel 202-1 into two equal parts by a straight line extending in the column direction. In this example, the straight line is a diagonal line of the first pixel 202-1. An element isolation portion is provided between the light receiving regions 214 so that charges generated according to incident light do not move between the light receiving regions 214. In FIG. 2A, the microlens 101 provided corresponding to the first pixel 202-1 is indicated by a dotted line. The two light receiving regions 214 in this example are provided at different positions in the row direction with respect to the common microlens 101.

  In the light receiving unit 200, a plurality of first pixels 202-1 are arranged adjacent to each other in the row direction. The signal processing unit 210 is an image plane in the row direction of signals from the first light receiving region 214a and signals from the second light receiving region 214b of the first pixels 202-1 arranged adjacent to each other in the row direction. By detecting the phase difference, it functions as a focus detection unit that detects the focus state. Since the first pixels 202-1 for detecting the image plane phase difference are arranged adjacent to each other in the row direction, the image plane phase difference in the row direction can be accurately detected. In addition, the light use efficiency can be improved as compared with the method of detecting the image plane phase difference using light shielding.

  FIG. 2B is a diagram illustrating an example of the second pixel 202-2 and the third pixel 202-3. The second pixel 202-2 and the third pixel 202-3 have two separated light receiving regions 214. The first light receiving region 214a and the second light receiving region 214b of the second pixel 202-2 and the third pixel 202-3 are arranged side by side in the column direction. In this example, the two light receiving regions 214 are defined by dividing the region of the second pixel 202-2 or the third pixel 202-3 into two equal parts by a straight line extending in the row direction. The two light receiving regions 214 of the second pixel 202-2 and the third pixel 202-3 are provided at different positions in the column direction with respect to the common microlens 101.

  In the light receiving unit 200, a plurality of second pixels 202-2 or third pixels 202-3 are arranged adjacent to each other in the column direction. The signal processing unit 210 includes a signal from the first light receiving region 214a and a signal from the second light receiving region 214b of the second pixel 202-2 or the third pixel 202-3 arranged adjacent to each other in the column direction. By detecting the image plane phase difference in the column direction, it functions as a focus detection unit that detects the focus state. Since the second pixel 202-2 or the third pixel 202-3 for detecting the image plane phase difference is arranged adjacent to the column direction, the image plane phase difference in the column direction can be accurately detected. In addition, the light use efficiency can be improved as compared with the method of detecting the image plane phase difference using light shielding.

  FIG. 3 is a diagram illustrating an example of the light receiving unit 200. In the light receiving unit 200 of this example, all the pixels 202 have two light receiving regions 214. In FIG. 3, the boundary of the light receiving region 214 in each pixel 202 is indicated by a dotted line. In this example, image data is generated using outputs from some pixels 202, and outputs from the remaining pixels 202 are used for image plane phase difference detection.

  In FIG. 3, the pixels 202 used for generating image data are indicated by white squares, and the pixels 202 used for image plane phase difference detection are indicated by shaded squares. As described above, the first pixels 202-1 for detecting the image plane phase difference are arranged side by side in the column direction, and the second pixels 202-2 for detecting the image plane phase difference are arranged side by side in the row direction. The third pixels 202-3 for detecting the surface phase difference are arranged side by side in the row direction. As described above, the signal processing unit 210 detects the image plane phase difference using the output of the pixel 202 for detecting the image plane phase difference.

  Further, the signal processing unit 210 corrects the output signal of the other light receiving region 214 by using the output signal of one light receiving region 214 in the pixel 202 for generating image data. The corrected signal is used as a pixel signal in the pixel 202. In the light receiving unit 200 of this example, the number of pixels 202 for generating image data is larger than the number of pixels 202 for detecting the image plane phase difference.

  FIG. 4 is a diagram illustrating a processing example of the signal processing unit 210 for the output of the pixel 202 for generating image data. The signal processing unit 210 of this example selects the pixels 202 from which the output signal of the light receiving region 214 is read out in units of rows. The signal processing unit 210 simultaneously reads output signals from the pixels 202 belonging to the selected row. In this case, the read timing of the output signal is different for each row, and the charge accumulation time is different for each row. The signal processing unit 210 of this example compensates for the difference in the charge accumulation time by correcting the output signal of the first light receiving region 214a using the output signal of the second light receiving region 214b of each pixel 202. In the light receiving unit 200 of this example, all the pixels 202 have two light receiving regions 214.

  In FIG. 4, the charge accumulation time of the first light receiving region 214a of the pixel 202 belonging to the first row is indicated by a1, and the charge accumulation time of the second light receiving region 214b is indicated by b1. In addition, the charge accumulation time of the first light receiving region 214a of the pixels 202 belonging to the second row is denoted by a2, and the charge accumulation time of the second light receiving region 214b is denoted by b2. The same applies to the other rows. Further, ADC in FIG. 4 indicates time for digitally converting the output signal of each light receiving area 214.

  As shown in FIG. 4, the signal processing unit 210 delays the reset timing B of the second light receiving region 214b with respect to the reset timing A for resetting the charge accumulated in the first light receiving region 214a for each pixel 202. For this reason, the light receiving unit 200 has a reset line that independently controls the reset timing of the first light receiving region 214a and the second light receiving region 214b of each pixel 202. The reset timing A and the reset timing B are common to all the pixels 202.

  Then, the signal processing unit 210 simultaneously reads out an output signal corresponding to the amount of charge accumulated in the first light receiving region 214a and the second light receiving region 214b for each pixel 202. For this reason, the light receiving unit 200 has a readout line that transmits the output signals of the first light receiving region 214a and the second light receiving region 214b of each pixel 202 in parallel. The signal processing unit 210 includes a processing circuit that processes output signals from the first light receiving region 214a and the second light receiving region 214b of each pixel 202 in parallel.

  For each pixel 202, the signal processing unit 210 subtracts the value of the output signal of the second light receiving area 214b from the value of the output signal of the first light receiving area 214a to generate a pixel signal of each pixel 202. Thereby, in all the pixels 202, a pixel signal corresponding to the charge accumulation time from the reset timing A to the reset timing B can be generated. By such processing, a pixel signal by a global shutter can be generated in a pseudo manner from an output signal read by rolling reading. The signal processing unit 210 also functions as a global shutter processing unit that performs the processing described in FIG.

  FIG. 5 is a diagram illustrating a configuration example of the light receiving unit 200. Although only the configuration related to one pixel 202 is shown in FIG. 5, the light receiving unit 200 has the same configuration for all the pixels 202. As described above, the light receiving unit 200 includes the reset line 221-1 that controls the reset timing of the first light receiving region 214a and the reset line 221-2 that controls the reset timing of the second light receiving region 214b. The reset line 221-1 and the reset line 221-2 are provided for each row of the pixels 202. Pixels 202 included in the same row are connected to a common reset line 221-1 and reset line 221-2.

  In addition, the light receiving unit 200 includes a read line 224-1 for reading the output signal of the first light receiving region 214a and a read line 224-2 for reading the output signal of the second light receiving region 214b. The readout line 224-1 and the readout line 224-2 are provided for each column of the pixels 202. Pixels 202 included in the same column are connected to a common readout line 224-1 and readout line 224-2. The readout line 224 transmits each output signal to the signal processing unit 210.

  Note that the signal processing unit 210 selects a row from which an output signal is read based on the row selection signal SEL. Further, the signal processing unit 210 selects the light receiving region 214 to which the output signal is to be transferred, based on the transfer signals Tx1 and Tx2.

  With such a configuration, the signal processing unit 210 simultaneously outputs an output signal corresponding to the amount of charge accumulated in the first light receiving region 214a and the second light receiving region 214b for each pixel 202 and independently for each light receiving region. It functions as a reading unit that reads out data. Further, the signal processing unit 210 can artificially generate a pixel signal by the global shutter from the output signal read by rolling reading. Since the output signal of the first light receiving region 214a is corrected using the output signal of the second light receiving region 214b, it is preferable that the light is equally incident on the first light receiving region 214a and the second light receiving region 214b. However, since the first light receiving region 214a and the second light receiving region 214b are provided at different positions, the light may not be evenly incident on the first light receiving region 214a and the second light receiving region 214b.

  Usually, the microlens 101 in the image sensor 100 is arranged so as to be shifted with respect to the pixel 202 in accordance with the position of the pixel 202 with respect to the optical axis. By designing in this way, a light spot is arranged at the center of the pixel 202 at any position of the pixel 202 with respect to a lens having a specific EPD value. The EPD value is a value indicating the distance from the image plane (the surface of the image sensor 100) to the exit pupil of the lens. As described above, the EPD value in which the light spot is at the center of the pixel 202 regardless of the position of the pixel 202 is referred to as EPD just.

  On the other hand, in a lens in which the EPD is shorter or a lens in which the EPD is longer than that of the EPD just lens, the light spot is shifted from the center of the pixel 202 depending on the position of the pixel 202. Since the pixel 202 is divided into two light receiving regions 214 along the center line, if the spot of light deviates from the center of the pixel 202, a difference occurs in the magnitude of the output signal in the two light receiving regions 214. For example, at a position away from the optical axis, most of the light spot is included in one light receiving area 214, and the output signal of the light receiving area 214 becomes very large, whereas the other light receiving area 214 The output signal of 214 becomes very small. Thus, light is not necessarily incident on the two light receiving regions 214 evenly.

  Although it is conceivable to correct the output signal of the light receiving region 214 in accordance with the EPD value described above, light may not be incident on one light receiving region 214 depending on conditions. In this case, the output signal cannot be corrected by calculation.

  FIG. 6 is a diagram illustrating a structure example of the light receiving unit 200. FIG. 6 shows a cross-sectional structure of the light receiving unit 200. In FIG. 6, only a portion of the light receiving unit 200 corresponding to the two pixels 202 for generating image data is shown. The light receiving unit 200 includes a magnifying optical element 114 corresponding to the pixel 202 for generating image data. The magnifying optical element 114 enlarges the irradiation area in the light receiving area 214 of light incident on the corresponding pixel 202. That is, the magnifying optical element 114 equalizes the amount of light incident on the two light receiving regions 214. The magnifying optical element 114 is, for example, a diffusion plate that diffuses and outputs incident light, or a diffraction plate on which a diffraction grating is formed.

  The magnifying optical element 114 is provided on the optical path of the incident light to the pixel 202. In this example, the magnifying optical element 114 is provided between the color filter 102 corresponding to the pixel 202 and the light receiving region 214. However, the position of the magnifying optical element 114 is not limited to this position. The magnifying optical element 114 may be provided between the color filter 102 and the microlens 101 or may be provided at another position.

  As shown in FIG. 6, a pixel separation unit 115 is formed between the pixels 202. In addition, a region separation unit 116 is formed between the two light receiving regions 214 in each pixel 202. The pixel separation unit 115 and the region separation unit 116 may be formed of an insulating material.

  Even in the case where the spot of incident light is biased toward one light receiving region 214, the bias of the light amount can be reduced by providing the magnifying optical element 114. Further, even when the majority of the incident light spot is located on the region separation unit 116, the incident light can be dispersed in the two light receiving regions 214 by providing the magnifying optical element 114. Thus, by providing the magnifying optical element 114 with respect to the pixel 202 for generating image data, which is a part of the pixel 202 of the light receiving unit 200, a pixel signal can be generated with high accuracy.

  FIG. 7 is a diagram illustrating a structural example of the light receiving unit 200. FIG. 7 shows a cross-sectional structure of the light receiving unit 200. In FIG. 7, only a portion of the light receiving unit 200 corresponding to the two pixels 202 for detecting the image plane phase difference is shown. The light receiving unit 200 includes a separation optical element 117 corresponding to the image plane phase difference detection pixel 202. That is, the separation optical element 117 is provided for a pixel in which the magnifying optical element 114 is not provided.

  The separation optical element 117 separates incident light into each of the two light receiving regions 214. That is, the separation optical element 117 separates the light beam that has passed through the microlens 101 into a pair of separated light beams, and causes each separated light beam to enter the corresponding light receiving region 214. The separation optical element 117 is preferably arranged so that the exit pupil plane of the photographing optical system and the arrangement surface on which the separation optical element 117 is arranged are optically conjugate by the microlens 101. The separation optical element 117 is, for example, a prism or a lens. The separation optical element 117 has a prism or a lens for each light receiving region 214. The prism or lens irradiates the corresponding light receiving area 214 with a separated light beam.

  The separation optical element 117 is provided on the optical path of the incident light to the pixel 202. In this example, the separation optical element 117 is provided between the color filter 102 corresponding to the pixel 202 and the light receiving region 214. However, the position of the separation optical element 117 is not limited to the position. The separation optical element 117 may be provided between the color filter 102 and the microlens 101 or may be provided at another position.

  The light receiving unit 200 may further include a light shielding mask 118. The light shielding mask 118 is provided on substantially the same plane as the separation optical element 117 and is provided with an opening through which the separated light beam separated by the separation optical element 117 is passed.

  As shown in FIGS. 6 and 7, the light receiving unit 200 is provided with a magnifying optical element 114 for the image data generation pixel 202, and a separation optical element for the image plane phase difference detection pixel 202. 117 is provided. Thereby, it is possible to detect the image plane phase difference with high accuracy while generating the pixel signal with high accuracy.

  The signal processing unit 210 also functions as an array conversion unit that converts image data based on each pixel signal from the light receiving unit 200 into image data of a predetermined pixel array such as a Bayer array. As described above, the signal processing unit 210 generates a pixel signal of each pixel 202 using signals from the two light receiving regions 214 of each pixel 202 for generating image data. For the image plane phase difference detection pixel 202, a pixel signal may be generated using the output value of the pixel 202 around the pixel 202. For example, the signal processing unit 210 generates a pixel signal of the pixel 202 by interpolating the output values of the surrounding pixels 202 of the same color.

  FIG. 8 is a diagram illustrating an example of array conversion processing in the signal processing unit 210. In FIG. 8, the number of each column of the plurality of pixels 202 is m, m + 1, m + 2,..., M + k,..., And the number of each row is n, n + 1, n + 2,.・ Let's say. However, k and l are integers. In FIG. 8, a process of generating a converted pixel signal of the first converted pixel 203-1 after the array conversion from the pixel signal of the first pixel 202-1 will be described. The first pixels 202-1 of this example are arranged in columns where k is 0 or even and rows where l is 0 or even.

  The signal processing unit 210 adds the pixel signals of the two first pixels 202-1 adjacent in the row direction, and the first conversion pixel 203 that is virtually arranged between the two first pixels 202-1. A conversion pixel signal of −1 is generated. In FIG. 8, two first pixels 202-1 to which pixel signals are added are connected by a double arrow.

  More specifically, the signal processing unit 210 groups the first pixels 202-1 in each row so as to form a pair of two adjacent first pixels 202-1. The signal processing unit 210 adds the pixel signals of the paired first pixels 202-1 to generate a converted pixel signal of the first converted pixel 203-1. At this time, the first pixels 202-1 in each row are grouped so that the positions in the row direction of the first conversion pixels 203-1 are alternately different for each row of the first pixels 202-1. For example, in the (n + s) th row (where s is 0, 4, 8,...), The first pixel 202-1 at the column position (m, m + 2), (m + 4, m + 6), (m + 8, m + 10). Are grouped. On the other hand, in the (n + s + 2) th row, the first pixels 202-1 at the column positions (m + 2, m + 4), (m + 6, m + 8), (m + 10, m + 12) are grouped.

  FIG. 9 is a diagram illustrating an arrangement example of the first conversion pixels 203-1. By the conversion process described in FIG. 8, the first conversion pixels 203-1 are arranged as shown in FIG. That is, the positions of the first conversion pixels 203-1 in the row direction are arranged to be alternately different for each row of the first conversion pixels 203-1. Specifically, in the (n + s) th row, the first conversion pixel 203-1 is arranged at column positions m + 1, m + 5, and m + 9. In the (n + s + 2) th row, the first conversion pixel 203-1 is arranged at the column positions of m + 3, m + 7, and m + 11.

  FIG. 10 is a diagram illustrating an example of array conversion processing in the signal processing unit 210. In FIG. 10, the process which produces | generates the conversion pixel signal of the 2nd conversion pixel 203-2 and the 3rd conversion pixel 203-3 after arrangement | sequence conversion from the pixel signal of the 2nd pixel 202-2 and the 3rd pixel 202-3. Will be explained. The second pixel 202-2 and the third pixel 202-3 in this example are arranged in a column in which k is an odd number. In this example, the second pixels 202-2 are arranged in columns of m + 3, m + 7, m + 11,. The third pixels 202-3 are arranged in columns of m + 1, m + 5, m + 9,.

  The signal processing unit 210 adds the pixel signals of the two second pixels 202-2 adjacent in the column direction, and the second conversion pixel 203 that is virtually disposed between the two second pixels 202-2. -2 conversion pixel signal is generated. Further, the signal processing unit 210 adds the pixel signals of the two third pixels 202-3 adjacent in the column direction, and performs a third conversion that is virtually arranged between the two third pixels 202-3. A converted pixel signal of the pixel 203-3 is generated. In FIG. 10, two pixels 202 to which pixel signals are added are joined by a double arrow.

  It should be noted that the double arrow connecting the two first pixels 202-1 described in FIG. 8, the double arrow connecting the two second pixels 202-2 described in FIG. 10, and the two third pixels 202-3 The pair of the second pixel 202-2 and the pair of the third pixel 202-3 to which the pixel signals are added are selected so that the connecting arrows do not overlap. That is, the pair of the second pixel 202-2 and the third pixel to which the pixel signals are added so that the positions of the first conversion pixel 203-1, the second conversion pixel 203-2, and the third conversion pixel 203-3 do not overlap. The pair 202-3 is selected.

  More specifically, in the second pixel 202-2, the second pixels 202-2 in the row positions of (n + 3, n + 5), (n + 7, n + 9), and (n + 11, n + 13) are grouped. On the other hand, the third pixel 202-3 is grouped by the third pixel 202-3 at the column positions (n + 1, n + 3), (n + 5, n + 7), (n + 9, n + 11).

  FIG. 11 is a diagram illustrating an arrangement example of the second conversion pixel 203-2 and the third conversion pixel 203-3. The second conversion pixel 203-2 and the third conversion pixel 203-3 are arranged as shown in FIG. 11 by the conversion process described in FIG. Specifically, in the m + 3, m + 7, and m + 11 columns, the second conversion pixel 203-2 is arranged at the row positions of n + 4, n + 8, and n + 12. In the (m + 1), (m + 5), and (m + 9) rows, the third conversion pixels 203-3 are arranged at the (n + 2, n + 6, n + 10) row positions.

  FIG. 12 is a diagram illustrating an arrangement example of the first conversion pixel 203-1, the second conversion pixel 203-2, and the third conversion pixel 203-3. The array illustrated in FIG. 12 is an array in which the arrays of the conversion pixels 203 illustrated in FIGS. 9 and 11 are overlapped. 8 to 11, the signal processing unit 210 can acquire Bayer array image data as shown in FIG.

  According to the imaging device 100 described above, the image plane phase difference detection pixels can be continuously arranged in the row direction and the column direction, so that the detection accuracy of the image plane phase difference can be improved. Then, Bayer array image data can be acquired by a simple calculation of adding pixel signals of adjacent pixels 202.

  13A and 13B are diagrams illustrating a structure example of the microlens 101. FIG. FIG. 13A is a perspective view of the microlens 101. However, a curved grid line indicates a curved surface, and a straight grid line indicates a plane. FIG. 13B is a diagram illustrating a planar shape of the microlens 101. As shown in FIGS. 13A and 13B, the microlens 101 has a shape obtained by cutting off four sides of a spherical lens. Thereby, a spherical lens with a large diameter can be used, and the substantial opening of the microlens 101 can be raised. Further, by matching the positions of the four sides of the microlens 101 with the positions of the four sides of the pixel 202, the microlens 101 can be efficiently spread.

  FIG. 14 is a diagram illustrating another configuration example of the light receiving unit 200. In this example, each light receiving region 214 is a photodiode. In the light receiving unit 200 of this example, the reset transistor R, the source follower transistor SF, and the selection transistor S are provided in common for the four photodiodes. For example, a reset transistor R and the like are provided in common for four photodiodes included in the region 240.

  Further, a transfer transistor TX is provided for each photodiode. The four photodiodes are included in different pixels 202, respectively. For example, four photodiodes sharing the reset transistor R and the like are included in two first pixels 202-1 and two second pixels 202-2.

  The transfer transistor TX switches whether to transfer the charge accumulated in the photodiode to the charge detection unit. The charge detection unit is, for example, a capacitor connected between the wiring and the reference potential (not shown). The charge detection unit is also shared by the four photodiodes.

  The reset transistor R switches whether to reset the charge transferred to the charge detection unit. The source follower transistor SF outputs an output signal corresponding to the charge accumulated in the charge detection unit. The selection transistor S switches whether to output an output signal to the readout line 224.

  FIG. 15 is a diagram illustrating an arrangement example of the transfer transistor TX and the charge detection unit in the example illustrated in FIG. In this example, the pixel 202 and the transistor are provided in different layers. Therefore, the pixel 202 and the transistor can be stacked. As described above, the charge detection unit, the reset transistor R, and the like are shared by the four photodiodes PD. Each photodiode PD is provided with a transfer transistor TX. In FIG. 15, the gate electrode of the transfer transistor TX is indicated by a hatched portion.

  The four photodiodes are included in two first pixels 202-1 and two second pixels 202-2 or third pixels 202-3. Since the first pixel 202-1 is different from the second pixel 202-2 and the third pixel 202-3 in the direction in which the pixels are divided, a region surrounded by the four transfer transistors TX is generated. This region functions as a charge detection unit. In FIG. 15, the reset transistor R and the like are omitted, but the reset transistor R and the like are also shared by four photodiodes as shown in FIG.

  FIG. 16 is a diagram illustrating an example of a cross section of the image sensor 100. In this example, the back-illuminated image sensor 100 is shown, but the image sensor 100 is not limited to the back-illuminated image sensor. Further, in FIG. 16, the magnifying optical element 114 and the separating optical element 117 shown in FIG. 6 are omitted. The imaging device 100 of this example includes an imaging chip 113 that outputs a signal corresponding to incident light, a signal processing chip 111 that processes a signal from the imaging chip 113, and a memory that stores image data processed by the signal processing chip 111. Chip 112. The imaging chip 113, the signal processing chip 111, and the memory chip 112 are stacked, and are electrically connected to each other by a conductive bump 109 such as Cu.

  As shown in the figure, incident light is incident mainly in the direction indicated by the white arrow. In the present embodiment, in the imaging chip 113, the surface on the side where incident light is incident is referred to as a back surface. An example of the imaging chip 113 is a back-illuminated MOS image sensor. The imaging chip 113 corresponds to the light receiving unit 200. The PD (photodiode) layer 106 is disposed on the back side of the wiring layer 108. The PD layer 106 includes a plurality of PD sections 104 that are two-dimensionally arranged and accumulate charges corresponding to incident light, and transistors 105 that are provided corresponding to the PD sections 104. One PD unit 104 is provided for one pixel 202. That is, the PD unit 104 has a first light receiving region 214a and a second light receiving region 214b.

  A color filter 102 is provided on the incident side of incident light in the PD layer 106 via a passivation film 103. The color filter 102 has a plurality of types that transmit different wavelength regions, and has a specific arrangement corresponding to each of the PD units 104. A set of the color filter 102, the PD unit 104, and the plurality of transistors 105 forms one pixel. By controlling on / off of the plurality of transistors 105, the reading timing of each light receiving region 214, the light receiving start timing (reset timing), and the like are controlled.

  On the incident light incident side of the color filter 102, a microlens 101 is provided corresponding to each pixel. The microlens 101 condenses incident light toward the corresponding PD unit 104.

  The wiring layer 108 includes a wiring 107 that transmits a signal from the PD layer 106 to the signal processing chip 111. The wiring 107 corresponds to, for example, the readout line 224 illustrated in FIG. In the wiring layer 108, gate electrodes of the transistors illustrated in FIGS. 5 and 14 may be formed. Further, the transistors shown in FIGS. 5 and 14 may be formed in the signal processing chip 111. In this case, the wiring 107 corresponds to a wiring that connects the PD layer 106 and each transistor. The wiring 107 may be multilayer, and a passive element and an active element may be provided. The signal processing chip 111 in this example includes a signal processing unit 210.

  A plurality of bumps 109 are disposed on the surface of the wiring layer 108. The plurality of bumps 109 are aligned with the plurality of bumps 109 provided on the opposing surfaces of the signal processing chip 111, and the imaging chip 113 and the signal processing chip 111 are pressed and aligned. The bumps 109 are joined and electrically connected.

  Similarly, a plurality of bumps 109 are disposed on the mutually facing surfaces of the signal processing chip 111 and the memory chip 112. The bumps 109 are aligned with each other, and the signal processing chip 111 and the memory chip 112 are pressurized, so that the aligned bumps 109 are joined and electrically connected.

  The bonding between the bumps 109 is not limited to Cu bump bonding by solid phase diffusion, and micro bump bonding by solder melting may be employed. Further, about one bump 109 may be provided for one unit block described later. Therefore, the size of the bump 109 may be larger than the pitch of the PD unit 104. Further, a bump larger than the bump 109 corresponding to the imaging region may be provided in a peripheral region other than the imaging region where the pixels are arranged.

  The signal processing chip 111 has a TSV (silicon through electrode) 110 that connects circuits provided on the front and back surfaces to each other. The TSV 110 is preferably provided in the peripheral area. The TSV 110 may also be provided in the peripheral area of the imaging chip 113 and the memory chip 112.

  FIG. 17 is a block diagram illustrating a configuration example of an imaging apparatus 500 according to an embodiment. The imaging apparatus 500 includes a photographic lens 520 as a photographic optical system, and the photographic lens 520 guides a subject luminous flux incident along the optical axis OA to the imaging element 100. The photographing lens 520 may be an interchangeable lens that can be attached to and detached from the imaging apparatus 500. The imaging apparatus 500 mainly includes an imaging device 100, a system control unit 501, a drive unit 502, a photometry unit 503, a work memory 504, a recording unit 505, a display unit 506, and a drive unit 514.

  The photographing lens 520 is composed of a plurality of optical lens groups, and forms an image of a subject light flux from the scene in the vicinity of its focal plane. In FIG. 17, the photographic lens 520 is representatively represented by a single virtual lens disposed in the vicinity of the pupil.

  The driving unit 514 drives the taking lens 520. More specifically, the drive unit 514 moves the optical lens group of the photographic lens 520 to change the focus position, and also drives the iris diaphragm in the photographic lens 520 to input the light amount of the subject luminous flux incident on the image sensor 100. To control.

  The drive unit 502 is a control circuit that executes charge accumulation control such as timing control and area control of the image sensor 100 in accordance with instructions from the system control unit 501. The driving unit 502 operates the light receiving unit 200 and the signal processing unit 210 of the image sensor 100 as described with reference to FIGS. Further, the operation unit 508 receives an instruction from the photographer through a release button or the like.

  The image sensor 100 is the same as the image sensor 100 described with reference to FIGS. The image sensor 100 delivers the pixel signal to the image processing unit 511 of the system control unit 501. The image processing unit 511 performs various image processing using the work memory 504 as a work space, and generates image data. For example, when generating image data in JPEG file format, a compression process is executed after generating a color video signal from a signal obtained by the Bayer array. The image processing unit 511 may include a signal processing unit 210. In this case, the image sensor 100 may not have the signal processing unit 210. The generated image data is recorded in the recording unit 505, converted into a display signal, and displayed on the display unit 506 for a preset time.

  The photometric unit 503 detects the luminance distribution of the scene prior to a series of shooting sequences for generating image data. The photometry unit 503 includes, for example, an AE sensor having about 1 million pixels. The calculation unit 512 of the system control unit 501 receives the output of the photometry unit 503 and calculates the luminance for each area of the scene. The calculation unit 512 determines the shutter speed, aperture value, and ISO sensitivity according to the calculated luminance distribution. The light metering unit 503 may be shared by the image sensor 100. Note that the arithmetic unit 512 also executes various arithmetic operations for operating the imaging device 500. A part or all of the drive unit 502 may be mounted on the signal processing chip 111 of the image sensor 100. A part of the system control unit 501 may be mounted on the signal processing chip 111 of the image sensor 100.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

  100 Image sensor, 101 Micro lens, 102 Color filter, 103 Passivation film, 104 PD part, 105 Transistor, 106 PD layer, 107 Wiring, 108 Wiring layer, 109 Bump, 110 TSV, 111 Signal processing chip, 112 Memory chip, 113 Imaging chip, 114 magnifying optical element, 115 pixel separating unit, 116 region separating unit, 117 separating optical element, 118 light shielding mask, 200 light receiving unit, 202 pixels, 203 conversion pixel, 210 signal processing unit, 214 light receiving region, 214a first Light receiving area, 214b Second light receiving area, 222-1, 222-2 reset line, 224 readout line, 260 correction section, 270 lookup table, 500 imaging device, 501 system control section, 502 drive section, 503 photometry section 504 a work memory, 505 a recording unit, 506 display unit, 508 operation unit, 511 image processing unit, 512 operation unit, 514 drive, 520 a photographing lens

Claims (14)

A plurality of pixels having two light receiving regions arranged along the first direction and the second direction and separated from each other;
An imaging device comprising: a magnifying optical element that is provided for a part of the plurality of pixels and that enlarges an irradiation region in the light receiving region of light incident on the corresponding pixel. The imaging device according to claim 1, further comprising a focus detection unit that detects a focus state of the imaging device based on output signals of the two light receiving regions of a pixel not provided with the magnifying optical element. For each pixel provided with the magnifying optical element, the reset timing of the second light receiving region is delayed with respect to the reset timing for resetting the charge accumulated in the first light receiving region of the two light receiving regions, and And simultaneously reading out an output signal corresponding to the amount of charge accumulated in the first light receiving region and the second light receiving region, and from the value of the output signal in the first light receiving region, the value of the output signal in the second light receiving region The image pickup device according to claim 1, further comprising a global shutter processing unit that subtracts and generates a pixel signal of the pixel. The apparatus further comprises a reading unit that simultaneously reads out an output signal corresponding to the amount of charge accumulated in each of the two light receiving regions and independently for each light receiving region for each pixel provided with the magnifying optical element. The image sensor according to 1 or 2. The imaging according to any one of claims 1 to 4, further comprising a separation optical element that is provided for a pixel not provided with the magnification optical element and separates incident light into each of the two light receiving regions. element. A color filter provided for each pixel;
The imaging device according to claim 1, wherein the magnifying optical element is provided between the pixel and the color filter. The plurality of pixels are:
A plurality of first pixels arranged along the first direction and the second direction and corresponding to a first color;
A plurality of other pixels provided in respective regions surrounded by four adjacent first pixels and corresponding to a color different from the first color, according to any one of claims 1 to 6. Image sensor. The plurality of other pixels are:
A plurality of second pixels arranged along the second direction and corresponding to a second color;
A plurality of third pixels arranged along the second direction and corresponding to a third color;
The second pixel columns and the third pixel columns are alternately arranged in the first direction,
The output signals of the two first pixels adjacent in the first direction are added to generate a pixel signal corresponding to the first color, and the output signals of the two second pixels adjacent in the second direction Is added to generate a pixel signal corresponding to the second color, and the output signals of two third pixels adjacent in the second direction are added to generate a pixel signal corresponding to the third color. The imaging device according to claim 7, further comprising an array conversion unit that performs the processing. The first pixel has a first light receiving region and a second light receiving region arranged side by side in the first direction,
The imaging device according to claim 8, wherein the second pixel and the third pixel have a first light receiving region and a second light receiving region arranged side by side in the second direction. The array conversion unit, for each pixel,
Generating a first pixel signal obtained by adding the output signal of the first light receiving region of the pixel and the output signal of the second light receiving region;
Generating a second pixel signal obtained by adding the output signal of the first light receiving region of the pixel and the output signal of the second light receiving region of the pixel adjacent to the first light receiving region of the pixel;
The third pixel signal is generated by adding the output signal of the second light receiving area of the pixel and the output signal of the first light receiving area of a pixel adjacent to the second light receiving area of the pixel. Image sensor. The planar shape of each pixel is a rectangle,
The image sensor according to any one of claims 1 to 10, wherein each side of the pixel is inclined 45 degrees with respect to the first direction and the second direction. 12. The apparatus according to claim 1, further comprising: a correction unit that corrects a value of an output signal output from each of the two light receiving regions based on lens data indicating characteristics of a lens through which light incident on the image sensor has passed. The imaging device according to claim 1. An imaging chip in which each pixel is formed;
The image pickup device according to claim 1, further comprising: a signal processing chip that is stacked with the image pickup chip and processes an output signal of each pixel.   An imaging device comprising the imaging device according to any one of claims 1 to 13.

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