Image sensor and imaging device

Abstract

To provide a novel image sensor and imaging device. [Solution] In an image sensor 5 having a plurality of pixels 61, each having a photoelectric conversion unit 61A and a charge holding unit 61B that holds the charge transferred from the photoelectric conversion unit 61A arranged in a row direction Y, the plurality of pixels 61 include a phase difference detection pixel 61R, and the photoelectric conversion unit 61A of the phase difference detection pixel 61R has a light-receiving area RR and a light-shielding area SR arranged in a row direction X that intersects the row direction Y, and the width of the photoelectric conversion unit 61A in the row direction X is greater than the width of the charge holding unit 61B in the row direction X.

Description

Technical Field

[0001] The present invention relates to an imaging device and an imaging apparatus.

Background Art

[0002] Patent Document 1 describes a solid-state imaging device having phase difference detection pixels. These phase difference detection pixels have photodiodes and a memory section arranged vertically, and an opening of a light shielding film is provided in approximately half of the left side or the right side of each of the photodiodes and the memory section.

[0003] Patent Document 2 describes an imaging device having pixels for phase difference detection. These pixels for phase difference detection have a photoelectric conversion section and a charge holding section arranged vertically, and an opening of a light shielding film is provided in approximately half of the left side or the right side of the photoelectric conversion section.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Means for Solving the Problems

[0005] The technology of the present disclosure is as follows.

[0006] (1) An imaging device having a plurality of pixels in which a photoelectric conversion section and a charge holding section for holding charges transferred from the photoelectric conversion section are arranged side by side in a first direction, the plurality of pixels includes a first pixel, in the photoelectric conversion section of the first pixel, a light receiving region and a light shielding region are arranged in a second direction intersecting the first direction. An image sensor in which the width of the photoelectric conversion section in the second direction is greater than the width of the charge holding section in the second direction.

[0007] (2) (1) The image sensor described above, The second direction mentioned above is the longitudinal direction of the image sensor.

[0008] (3) The image sensor described in (1) or (2), An image sensor in which the charge held in the charge holding portion of one of the two first pixels arranged adjacent to each other in the second direction described above, and the charge held in the charge holding portion of the other of the two first pixels, are configured to be mixable in the charge holding portions of the two first pixels.

[0009] (4) An image sensor as described in any of (1) to (3), The first pixel includes a first type pixel in which the light-receiving area is located on one side of the second direction and the light-shielding area is located on the other side of the second direction, and a second type pixel in which the light-receiving area is located on the other side of the second direction and the light-shielding area is located on one side of the second direction. An image sensor in which, in the first type pixel and the second type pixel arranged adjacent to each other in the second direction described above, the light-receiving area of ​​the first type pixel and the light-receiving area of ​​the second type pixel are arranged between the light-shielding area of ​​the first type pixel and the light-shielding area of ​​the second type pixel.

[0010] (5) (4) The image sensor described above, An image sensor in which the difference between the sum of the area of ​​the light-shielding region in the first type of pixel and the area of ​​the light-shielding region in the second type of pixel, and the sum of the area of ​​the light-receiving region in the first type of pixel and the area of ​​the light-receiving region in the second type of pixel, is less than or equal to a threshold.

[0011] (6) (4) The image sensor described above, The above-mentioned plurality of pixels include a second pixel in which the incident position of the principal ray of the imaging lens positioned in front of the image sensor coincides with the center of the light-receiving area of ​​the photoelectric conversion unit. An image sensor in which the difference between the sum of the area of ​​the light-receiving region in the first type of pixel and the area of ​​the light-receiving region in the second type of pixel and the area of ​​the light-receiving region in the second pixel is less than or equal to a threshold.

[0012] (7) An image sensor according to any of (4) to (6), In the second direction described above, the pairs of first-type pixels and second-type pixels that are adjacent to each other include the first pair. In the first pair described above, the boundary between the light-receiving regions is formed at an intermediate position between the center of the light-receiving region of the first type pixel and the center of the light-receiving region of the second type pixel.

[0013] (8) An image sensor according to any one of (4) to (7), The above pair of first-type pixels and second-type pixels includes a second pair, In the second pair described above, the midpoint between the center of the light-receiving region of the first type pixel and the center of the light-receiving region of the second type pixel is eccentric toward the edge of the image sensor compared to the boundary between the light-receiving regions.

[0014] (9) (8) The image sensor described above, The eccentricity of the intermediate position in the second pair described above increases as it approaches the edge of the image sensor.

[0015] (10) An image sensor having a plurality of pixels, each having a photoelectric conversion unit and a charge holding unit that holds the charge transferred from the photoelectric conversion unit arranged in a first direction, An imaging device in which charges held in one of the charge holding parts of two pixels arranged adjacent to each other in a second direction intersecting the first direction and charges held in the other charge holding part of the two pixels are configured to be mixable in the charge holding parts of the two pixels.

[0016] (11) An imaging device having a plurality of pixels in which a photoelectric conversion part and a charge holding part for holding charges transferred from the photoelectric conversion part are provided side by side in a first direction, the plurality of pixels includes a first pixel, in the photoelectric conversion part of the first pixel, a light receiving region and a light shielding region are arranged in a second direction intersecting the first direction, the first pixel includes a first type pixel in which the light receiving region is arranged on one side in the second direction and the light shielding region is arranged on the other side in the second direction, and a second type pixel in which the light receiving region is arranged on the other side in the second direction and the light shielding region is arranged on one side in the second direction, in the first type pixel and the second type pixel arranged adjacent to each other in the second direction, between the light shielding region of the first type pixel and the light shielding region of the second type pixel, the light receiving region of the first type pixel and the light receiving region of the second type pixel are arranged.

[0017] (12) An imaging device including the imaging device according to any one of (1) to (11).

Brief Description of Drawings

[0018] [Figure 1] It is a diagram showing a schematic configuration of a digital camera 100 which is an embodiment of an imaging device of the present invention. [Figure 2] It is a plan schematic diagram showing a schematic configuration of an imaging device 5 shown in FIG. 1. [Figure 3] It is a schematic diagram showing a configuration of a pixel 61 of the imaging device 5 shown in FIG. 2. [Figure 4] It is an enlarged view of a range HC of the imaging device 5 shown in FIG. 2. [Figure 5]Figure 2 is a magnified view of the HLE area of ​​the image sensor 5 shown in Figure 2. [Figure 6] Figure 2 is a magnified view of the HRE area of ​​the image sensor 5 shown in Figure 2. [Figure 7] This figure corresponds to Figure 4, which shows a first modified example of the image sensor 5. [Figure 8] This figure corresponds to Figure 4, which shows a second modified example of the image sensor 5. [Figure 9] This is a diagram showing the appearance of the Smartphone 200. [Figure 10] The block diagram shows the configuration of the smartphone 200 as shown in Figure 9. [Modes for carrying out the invention]

[0019] Figure 1 is a diagram showing the schematic configuration of a digital camera 100, which is one embodiment of the imaging device of the present invention. The digital camera 100 shown in Figure 1 comprises a lens device 40 having an imaging lens 1, an aperture 2, a lens drive unit 8 that drives the imaging lens 1, an aperture drive unit 9 that drives the aperture 2, and a lens control unit 4 that controls the lens drive unit 8 and the aperture drive unit 9, and a main body 100A.

[0020] The main unit 100A comprises an image sensor 5, a system control unit 11 that provides overall control of the entire electrical control system of the digital camera 100, an operation unit 14, a display device 22, a memory 16 including RAM (Random Access Memory) and ROM (Read Only Memory), a memory control unit 15 that controls data storage in the memory 16 and data reading from the memory 16, a digital signal processing unit 17, and an external memory control unit 20 that controls data storage in the storage medium 21 and data reading from the storage medium 21.

[0021] The lens device 40 may be detachable from the main body 100A, or it may be integrated with the main body 100A. The imaging lens 1 includes a focus lens that is movable in the optical axis direction. This focus lens is a lens for adjusting the focus of the imaging optical system, which includes the imaging lens 1 and the aperture 2, and is composed of a single lens or multiple lenses. As the focus lens moves in the optical axis direction, the position of the principal point of the focus lens changes along the optical axis direction, thereby changing the focal position on the subject side. As the focus lens, a liquid lens whose principal point position in the optical axis direction can be changed by electrical control may be used.

[0022] The lens control unit 4 of the lens device 40 controls the lens drive unit 8 based on the lens drive signal transmitted from the system control unit 11 to change the position of the principal point of the focus lens included in the imaging lens 1. The lens control unit 4 of the lens device 40 controls the aperture drive unit 9 based on the drive control signal transmitted from the system control unit 11 to change the aperture amount (F number) of the aperture 2.

[0023] The image sensor 5 captures an image of the subject through an imaging optical system that includes an imaging lens 1 and an aperture 2. The image sensor 5 has a light-receiving surface 60 (see Figure 2) in which multiple pixels are arranged in two dimensions, and the imaging optical system converts the image of the subject formed on this light-receiving surface 60 into a pixel signal using these multiple pixels and outputs it. For example, the image sensor 5 may be a CMOS (complementary metal-oxide semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor. Below, an example in which the image sensor 5 is a CMOS image sensor will be described.

[0024] The system control unit 11 provides overall control for the digital camera 100, and its hardware structure consists of various processors that execute programs and perform processing. The programs executed by the system control unit 11 are stored in the ROM of the memory 16.

[0025] Various types of processors include CPUs (Central Processing Units), which are general-purpose processors that execute programs and perform various processes; Programmable Logic Devices (PLDs), such as FPGAs (Field Programmable Gate Arrays), whose circuit configurations can be changed after manufacturing; and dedicated electrical circuits, such as ASICs (Application Specific Integrated Circuits), which have circuit configurations specifically designed to perform particular processes. More specifically, the structure of these various types of processors is an electrical circuit that combines circuit elements such as semiconductor elements.

[0026] The system control unit 11 may be composed of one of various processors, or it may be composed of a combination of two or more processors of the same or different types (for example, a combination of multiple FPGAs or a combination of a CPU and an FPGA).

[0027] The system control unit 11 drives the image sensor 5 and the lens device 40, and outputs the subject image captured through the imaging optical system of the lens device 40 as an image signal. The image signal output from the image sensor 5 is processed by the digital signal processing unit 17 to generate image data that is suitable for display on the display device 22 or suitable for storage on the storage medium 21.

[0028] The system control unit 11 receives instruction signals from the user through the operation unit 14. The operation unit 14 includes a touch panel integrated with the display surface 22b, as well as various buttons and other controls.

[0029] The display device 22 comprises a display surface 22b composed of an organic EL (electroluminescence) panel or a liquid crystal panel, and a display controller 22a that controls the display on the display surface 22b.

[0030] The memory control unit 15, the digital signal processing unit 17, the external memory control unit 20, and the display controller 22a are interconnected by a control bus 24 and a data bus 25, and are controlled by commands from the system control unit 11.

[0031] Figure 2 is a schematic plan view showing the general configuration of the image sensor 5 shown in Figure 1. Figure 3 is a schematic view showing the configuration of the pixels 61 of the image sensor 5 shown in Figure 2.

[0032] The image sensor 5 comprises a light-receiving surface 60 in which multiple pixel rows 62, each consisting of multiple pixels 61 arranged in the row direction X, are arranged in the column direction Y, which intersects (orthogonal in the example shown in the figure) with the row direction X; a drive circuit 63 for driving the pixels 61 arranged on the light-receiving surface 60; and a signal processing circuit 64 for processing the pixel signals read out to the signal lines from each pixel 61 of the pixel rows 62 arranged on the light-receiving surface 60. The light-receiving surface 60 is rectangular in shape with the row direction X as its longitudinal direction, and as a result, the image sensor 5 is rectangular in shape with the row direction X as its longitudinal direction. The column direction Y constitutes the first direction. The row direction X constitutes the second direction.

[0033] The multiple pixels 61 include a first pixel, which includes a first type pixel and a second type pixel, and a second pixel. The first type pixel is a phase difference detection pixel 61R, described later, that receives one of a pair of light beams that have passed through two different parts aligned in the row direction X of the pupil region of the imaging optical system of the lens device 40 and detects a signal corresponding to the amount of light received. The second type pixel is a phase difference detection pixel 61L, described later, that receives the other of this pair of light beams and detects a signal corresponding to the amount of light received. The second pixel is a normal pixel 61W, described later, that receives both of this pair of light beams and detects a signal corresponding to the amount of light received.

[0034] Pixel row 62 includes a first pixel row containing only normal pixels 61W, and a second pixel row containing phase difference detection pixels 61R, phase difference detection pixels 61L, and normal pixels 61W, with the second pixel row being discretely arranged at equal intervals in the column direction Y.

[0035] In the following, in Figure 2, the upper end of the light-receiving surface 60 in the column direction Y will be referred to as the upper end, and the lower end of the light-receiving surface 60 in the column direction Y will be referred to as the lower end. Also, in Figure 2, the right end of the light-receiving surface 60 in the row direction X will be referred to as the right end, and the left end of the light-receiving surface 60 in the row direction X will be referred to as the left end.

[0036] As shown in Figure 3, the pixel 61 includes a photoelectric conversion unit 61A, a charge holding unit 61B, a charge transfer unit 61C, a floating diffusion 61D, and a readout circuit 61E.

[0037] The photoelectric conversion unit 61A receives light that has passed through the imaging optical system of the lens device 40 and generates and stores an electric charge corresponding to the amount of light received. The photoelectric conversion unit 61A is composed of a photodiode or the like. In the example in Figure 3, a P-well layer 71 is formed on the surface of the N-type substrate 70, and the photoelectric conversion unit 61A is formed on the surface of the P-well layer 71. The photoelectric conversion unit 61A is composed of an N-type impurity layer 73 and a P-type impurity layer 74 formed on it. The N-type substrate 70 and the P-well layer 71 constitute a semiconductor substrate.

[0038] The charge transfer unit 61C transfers the charge accumulated in the photoelectric conversion unit 61A to the charge holding unit 61B. In the example shown in Figure 3, the charge transfer unit 61C is composed of an impurity region in the semiconductor substrate and an electrode formed above this impurity region. The voltage applied to this electrode is controlled by the drive circuit 63, thereby transferring charge from the photoelectric conversion unit 61A to the charge holding unit 61B.

[0039] The charge-holding section 61B holds the charge transferred from the photoelectric conversion section 61A by the charge transfer section 61C. The charge-holding section 61B is composed of impurity regions within the semiconductor substrate. In the example shown in Figure 3, the charge-holding section 61B, made of an N-type impurity layer, is formed on the surface of the P-well layer 71, slightly separated from the photoelectric conversion section 61A.

[0040] A transfer electrode 76 is formed above the region 75 of the P-well layer 71 between the charge holding portion 61B and the photoelectric conversion portion 61A, via an oxide film (not shown). The region 75 and the transfer electrode 76 constitute the charge transfer portion 61C.

[0041] By controlling the potential of the transfer electrode 76 to form a channel in region 75, the charge accumulated in the photoelectric conversion unit 61A can be transferred to the charge holding unit 61B. The potential of the transfer electrode 76 is controlled by the drive circuit 63.

[0042] The floating diffusion 61D is for converting charge into a signal, and the charge held in the charge holding portion 61B is transferred to it. In the example in Figure 3, the floating diffusion 61D, which consists of an N-type impurity layer, is formed on the surface of the P-well layer 71, slightly separated from the charge holding portion 61B. Above the P-well layer 71 between the charge holding portion 61B and the floating diffusion 61D, a readout electrode 72 is formed via an oxide film (not shown).

[0043] By controlling the potential of the readout electrode 72 and forming a channel in the region between the charge holding section 61B and the floating diffusion 61D, the charge held in the charge holding section 61B can be transferred to the floating diffusion 61D. The potential of the readout electrode 72 is controlled by the drive circuit 63.

[0044] The readout circuit 61E is a circuit that reads out a signal corresponding to the potential of the floating diffusion 61D as a pixel signal to the signal line 65. The readout circuit 61E is driven by the drive circuit 63.

[0045] In the example shown in Figure 3, the readout circuit 61E consists of a reset transistor 77 for resetting the potential of the floating diffusion 61D, an output transistor 78 for converting the potential of the floating diffusion 61D into a pixel signal and outputting it, and a selection transistor 79 for selectively reading the pixel signal output from the output transistor 78 to the signal line 65. The configuration of the readout circuit is just one example and is not limited to this. The readout circuit 61E may also be shared by multiple pixels 61.

[0046] Pixel 61 is provided with a light-shielding film (not shown), and areas other than the photoelectric conversion unit 61A are shielded from light by this film. The structure of pixel 61 shown in Figure 3 is an example and is not limited thereto.

[0047] The signal processing circuit 64 shown in Figure 2 performs correlated double sampling on the pixel signals read from each pixel 61 of the pixel row 62 to the signal line 65, converts the pixel signals after correlated double sampling into digital signals, and outputs them to the data bus 25 (see Figure 1). The signal processing circuit 64 is controlled by the system control unit 11. The digital signal processing unit 17 performs signal processing such as demosaicing and gamma correction on the group of pixel signals output from the image sensor 5 to the data bus 25 to generate image data.

[0048] Figure 4 is a magnified view of the range HC in the central part of the image sensor 5 shown in Figure 2. Figure 5 is a magnified view of the range HLE in the peripheral part (left end) of the image sensor 5 shown in Figure 2. Figure 6 is a magnified view of the range HRE in the peripheral part (right end) of the image sensor 5 shown in Figure 2. In Figures 4, 5, and 6, the charge transfer unit 61C and the readout circuit 61E are not shown. The ranges HLE, HC, and HRE each include a first pixel row (a pixel row containing only normal pixels) and a second pixel row (a pixel row containing phase difference detection pixels and normal pixels), respectively.

[0049] In Figures 4 and 5, the upper pixel row is the second pixel row, with normal pixels 61W, phase difference detection pixels 61R, phase difference detection pixels 61L, and normal pixels 61W arranged in this order along the row direction X. In Figures 4 and 5, the lower pixel row is the first pixel row, with four normal pixels 61W arranged along the row direction X.

[0050] Each pixel 61 has a rectangular photoelectric conversion unit 61A extending in the row direction X and a rectangular charge holding unit 61B extending in the row direction X, arranged side by side in the column direction Y. In each pixel 61, the width of the photoelectric conversion unit 61A in the row direction X is greater than the width of the charge holding unit 61B in the row direction X.

[0051] In the light-receiving surface 60, the structure within the semiconductor substrate of two adjacent pixels 61 in the row direction X is symmetrical with respect to the boundary line between these two pixels 61 as the axis of symmetry.

[0052] For example, consider the pair of the leftmost and uppermost normal pixel 61W in Figure 4 and the phase difference detection pixel 61R located to its right. In this pair, the center of the row direction X of the charge holding unit 61B of the normal pixel 61W is located to the left of the center of the row direction X of the photoelectric conversion unit 61A, whereas in the phase difference detection pixel 61R, the center of the row direction X of the charge holding unit 61B is located to the right of the center of the row direction X of the photoelectric conversion unit 61A. A floating diffusion 61D, which is common to this pair, is provided between the two charge holding units 61B.

[0053] Each pixel row 62 formed on the light-receiving surface 60 consists of two pixels 61 (hereinafter referred to as a pixel pair) with the same structure as the pair, arranged repeatedly in the row direction X. The floating diffusion 61D in the pixel pair may be divided at the boundary line of the pixel pair, with one diffusion 61 provided for each pixel 61.

[0054] In the second pixel row, of the four pixels 61 in two adjacent pixel pairs in the row direction X, the two pixels 61 adjacent to each other across the boundary between these two pixel pairs form a phase difference detection pixel 61R and a phase difference detection pixel 61L. More specifically, of these two pixels 61, the left pixel 61 is the phase difference detection pixel 61R, and the right pixel 61 is the phase difference detection pixel 61L.

[0055] In the image sensor 5, for example, the principal ray of the imaging lens 1 is incident on the center of the column direction Y and row direction X of the photoelectric conversion unit 61A at each pixel 61.

[0056] A light-shielding film 50 is formed above the semiconductor substrate in each pixel 61. In the light-shielding film 50, an aperture 50W is formed above the photoelectric conversion section 61A in a normal pixel 61W. In a normal pixel 61W, the center of the column direction Y of the photoelectric conversion section 61A coincides with the center of the row direction X of the aperture 50W.

[0057] In the plan view of Figure 4, the region of the photoelectric conversion unit 61A exposed from the aperture 50W forms the light-receiving area RW of the normal pixel 61W. The principal rays of the imaging lens 1 are incident on the center of the column direction Y and row direction X of the light-receiving area RW of the normal pixel 61W. In other words, the incident position of the principal rays of the imaging lens 1 coincides with the center of the light-receiving area RW of the normal pixel 61W.

[0058] The light-shielding film 50 further has an aperture 50R formed above the photoelectric conversion unit 61A in the phase difference detection pixel 61R, and an aperture 50L formed above the photoelectric conversion unit 61A in the phase difference detection pixel 61L. The aperture 50R has its center CR in the column direction Y and row direction X shifted to the right in the row direction X compared to the center in the column direction Y and row direction X of the photoelectric conversion unit 61A in the phase difference detection pixel 61R (i.e., the incident position of the principal ray of the imaging lens 1). The aperture 50L has its center CL in the column direction Y and row direction X shifted to the left in the row direction X compared to the center in the column direction Y and row direction X of the photoelectric conversion unit 61A in the phase difference detection pixel 61L (i.e., the incident position of the principal ray of the imaging lens 1).

[0059] The region of the photoelectric conversion unit 61A exposed from aperture 50R forms the light-receiving region RR of the phase difference detection pixel 61R. The region of the photoelectric conversion unit 61A exposed from aperture 50L forms the light-receiving region RL of the phase difference detection pixel 61L. The phase difference detection pixel 61R can be said to have a configuration in which the light-receiving region RR is eccentric to the right in the row direction X relative to the photoelectric conversion unit 61A. The phase difference detection pixel 61L can be said to have a configuration in which the light-receiving region RL is eccentric to the left in the row direction X relative to the photoelectric conversion unit 61A.

[0060] Here, a virtual line extending from the upper edge of the aperture 50R (one edge in the column direction Y) in the row direction X is defined as virtual line Lu, and a virtual line extending from the lower edge of the aperture 50R (the other edge in the column direction Y) in the row direction X is defined as virtual line Ld. In the phase difference detection pixel 61R, the widest area of ​​the light-shielded region in the photoelectric conversion unit 61A between virtual line Lu and virtual line Ld (the area to the left of the light-receiving region RR) is defined as the light-shielded region SR of the photoelectric conversion unit 61A in the phase difference detection pixel 61R.

[0061] Furthermore, in the phase difference detection pixel 61L, the widest area (the area to the right of the light-receiving area RL) among the light-shielded areas in the photoelectric conversion unit 61A between the virtual line Lu and the virtual line Ld is defined as the light-shielded area SL of the photoelectric conversion unit 61A in the phase difference detection pixel 61L.

[0062] With this definition, the phase difference detection pixel 61R can be described as having a configuration in which the light-receiving area RR and the light-shielding area SR are aligned in the row direction X, and the light-shielding area SR is positioned to the left of the light-receiving area RR. Furthermore, the phase difference detection pixel 61L can be described as having a configuration in which the light-receiving area RL and the light-shielding area SL are aligned in the row direction X, and the light-shielding area SL is positioned to the right of the light-receiving area RL.

[0063] Thus, in the image sensor 5, pairs of phase-difference detection pixels 61R and 61L are arranged adjacent to each other in the row direction X. In the phase-difference detection pixels 61R and 61L that are arranged adjacent to each other in the row direction X, the light-receiving area RR of the phase-difference detection pixel 61R and the light-receiving area RL of the phase-difference detection pixel 61L are positioned between the light-shielding area SR of the phase-difference detection pixel 61R and the light-shielding area SL of the phase-difference detection pixel 61L.

[0064] As shown in Figure 4, in a pair of phase-difference detection pixels 61R and 61L arranged adjacent to each other in the central part of the light-receiving surface 60 (near the position where it intersects with the optical axis of the imaging optical system), the boundary between these phase-difference detection pixels 61R and 61L is formed at a position midway between the center of the row direction X of the light-receiving area RR and the center of the row direction X of the light-receiving area RL. The pair of phase-difference detection pixels 61R and 61L shown in Figure 4 constitutes the first pair.

[0065] On the other hand, in pairs of phase-difference detection pixels 61R and 61L arranged adjacent to each other in the peripheral area of ​​the light-receiving surface 60 (close to the edge of the image sensor 5), the midpoint between the center of the row direction X of the light-receiving area RR and the center of the row direction X of the light-receiving area RL is eccentric toward the edge of the image sensor 5 (the left edge of the image sensor 5 in the example of Figure 5, and the right edge of the image sensor 5 in the example of Figure 6) compared to the boundary between these phase-difference detection pixels 61R and 61L. Furthermore, the amount of eccentricity at this midpoint increases the closer it is to the edge of the image sensor 5 (closer to the right or left edge of the light-receiving surface 60). As shown in Figures 5 and 6, pairs of phase-difference detection pixels 61R and 61L with an eccentric midpoint constitute a second pair.

[0066] With the image sensor 5 configured as described above, for example, by performing a correlation calculation between a group of pixel signals read from multiple phase difference detection pixels 61R included in the same pixel row 62 and a group of pixel signals read from multiple phase difference detection pixels 61L, the phase difference between these two groups of pixel signals in the row direction X can be derived. This phase difference can be used to control the principal point position of the focus lens.

[0067] The image sensor 5 has a horizontally elongated shape extending in the row direction X. The angle between the light rays incident on the light-receiving surface 60 and the optical axis of the imaging optical system is defined as the light incidence angle. At the right and left ends of the light-receiving surface 60, the light incidence angle is larger than at the upper and lower ends of the light-receiving surface 60. In the image sensor 5, the photoelectric conversion unit 61A in each pixel 61 has a horizontally elongated shape extending in the row direction X. Therefore, light can be efficiently captured in the normal pixels 61W at the right and left ends of the image sensor 5 where the light incidence angle is large. In addition, because the photoelectric conversion unit 61A has a horizontally elongated shape, the light-receiving areas of the phase difference detection pixels 61R and 61L can be enlarged horizontally, improving the sensitivity of the phase difference detection pixels. As a result, the accuracy of phase difference derivation can be improved, making it possible to perform focus adjustment with high precision.

[0068] Furthermore, in the image sensor 5, the light-receiving areas of adjacent phase-difference detection pixels 61R and 61L are arranged in close proximity in the row direction X. With this configuration, for example, by adding the pixel signals read from each of the phase-difference detection pixel pairs 61R and 61L, a pixel signal similar to the pixel signal read from a normal pixel 61W can be obtained. Therefore, the image quality can be improved when generating captured image data using the pixel signals read from the phase-difference detection pixels.

[0069] Furthermore, it is preferable that the difference between the sum of the areas of the light-shielding region SR and the light-shielding region SL and the sum of the areas of the light-receiving region RR and the light-receiving region RL is less than or equal to the first threshold (i.e., sufficiently small). Ideally, this difference should be zero. By doing so, it becomes easier to bring the sum of the areas of the light-receiving region RR and the light-receiving region RL closer to the area of ​​the light-receiving region RW. As a result, it is possible to improve the image quality when generating captured image data using the pixel signals read out from the phase-difference detection pixels.

[0070] Alternatively, instead of setting the above difference to be less than or equal to the first threshold, the difference between the sum of the areas of the light-receiving regions RR and RL and the area of ​​the light-receiving region RW may be set to be less than or equal to the second threshold. Ideally, this difference should be zero. Even in this way, the image quality when generating captured image data using the pixel signals read out from the phase difference detection pixels can be improved.

[0071] In the image sensor 5, as shown in Figures 5 and 6, the area of ​​the light-receiving region RR of the phase-difference detection pixel 61R increases as it moves to the left of the center of the row direction X on the light-receiving surface 60. Similarly, the area of ​​the light-receiving region RL of the phase-difference detection pixel 61L increases as it moves to the right of the center of the row direction X on the light-receiving surface 60. Therefore, even in areas with a large image height, the sensitivity of the phase-difference detection pixels 61R and 61L can be increased, improving the accuracy of phase difference derivation.

[0072] Figure 7 is a diagram corresponding to Figure 4, showing a first modified example of the image sensor 5. In this modified example, a gate electrode G1 is added between the boundary portion of the charge holding portion 61B of each adjacent pair of phase difference detection pixels 61R and phase difference detection pixels 61L, and the light-shielding film 50. The potential of the gate electrode G1 is controlled by the drive circuit 63.

[0073] When a voltage is applied to the gate electrode G1, a channel is formed in the semiconductor substrate below the gate electrode G1, eliminating the potential barrier at the boundary between the charge holding portions 61B of the phase difference detection pixel 61R and phase difference detection pixel 61L pair. As a result, the charges held in the charge holding portions 61B of the phase difference detection pixel 61R and phase difference detection pixel 61L pair can be mixed between these two charge holding portions 61B.

[0074] According to the modified example shown in Figure 7, since the charges can be mixed in the charge holding unit 61B, the processing can be simplified compared to the case where the pixel signal of the phase difference detection pixel 61R and the pixel signal of the phase difference detection pixel 61L are added together by signal processing.

[0075] Figure 8 is a diagram corresponding to Figure 4, showing a second modified example of the image sensor 5. In this modified example, compared to the configuration shown in Figure 7, a gate electrode G2 is added between the boundary portion of the charge holding portion 61B of two adjacent normal pixels 61W in the row direction X and the light-shielding film 50. The potential of the gate electrode G2 is controlled by the drive circuit 63.

[0076] When a voltage is applied to the gate electrode G2, a channel is formed in the semiconductor substrate below the gate electrode G2, eliminating the potential barrier at the boundary between the charge holding portions 61B of two adjacent normal pixels 61W arranged in the row direction X. As a result, the charges held in the charge holding portions 61B of two adjacent normal pixels 61W arranged in the row direction X can be mixed between these two charge holding portions 61B.

[0077] According to the modified example shown in Figure 8, even in a normal pixel 61W, the charge can be mixed in the charge holding section 61B. This enables high-sensitivity imaging. Note that in the modified example shown in Figure 8, the gate electrode G1 is not essential and may be omitted.

[0078] In the image sensor 5 shown in Figures 2 to 8, in the second pixel row, of the four pixels 61 in two adjacent pixel pairs in the row direction X, two pixels 61 adjacent to each other across the boundary between these two pixel pairs form a phase difference detection pixel 61R and a phase difference detection pixel 61L pair. As a variation of this, for example, two normal pixels 61W may be placed between these two pixel pairs. In other words, an adjacent pair of phase difference detection pixels 61R and 61L in the row direction X refers to a pair of phase difference detection pixels that are arranged at the shortest distance in the row direction X.

[0079] Furthermore, in the image sensor 5 shown in Figures 2 to 8, of the two adjacent pixels 61 separated by the boundary between the two pixel sets, the left one is a phase-difference detection pixel 61R, and the right one is a phase-difference detection pixel 61L. As a variation, the right pixel 61 may be a phase-difference detection pixel 61R, and the left pixel 61L. This also improves the sensitivity of the phase-difference detection pixels.

[0080] Furthermore, in the image sensor 5 shown in Figures 2 to 8, the apertures 50R and 50L of the pair of phase-difference detection pixels 61R and 61L may be combined into a single aperture.

[0081] Furthermore, in the image sensor 5 shown in Figures 2 to 8, the configuration includes a first pair and a second pair of phase-difference detection pixels. However, the first pair is not mandatory, and all pairs of phase-difference detection pixels may be second pairs.

[0082] Next, we will describe the configuration of a smartphone, which is another embodiment of the imaging device of the present invention.

[0083] Figure 9 shows the external appearance of the smartphone 200. The smartphone 200 shown in Figure 9 has a flat casing 201, and one side of the casing 201 is equipped with a display input unit 204 which is an integrated display panel 202 as a display unit and an operation panel 203 as an input unit.

[0084] Furthermore, such a housing 201 includes a speaker 205, a microphone 206, an operating unit 207, and a camera unit 208. However, the configuration of the housing 201 is not limited to this; for example, a configuration in which the display unit and input unit are independent, or a configuration having a folding structure or a sliding mechanism, can also be adopted.

[0085] Figure 10 is a block diagram showing the configuration of the smartphone 200 shown in Figure 9.

[0086] As shown in Figure 10, the main components of the smartphone include a wireless communication unit 210, a display input unit 204, a call unit 211, an operation unit 207, a camera unit 208, a storage unit 212, an external input / output unit 213, a GNSS (Global Navigation Satellite System) receiver unit 214, a motion sensor unit 215, a power supply unit 216, and a main control unit 220.

[0087] Furthermore, the main function of the smartphone 200 is to provide a wireless communication function that performs mobile wireless communication via a base station device BS (not shown) and a mobile communication network NW (not shown).

[0088] The wireless communication unit 210 performs wireless communication with base station equipment BS connected to the mobile communication network NW, in accordance with instructions from the main control unit 220. Using this wireless communication, it sends and receives various file data such as voice data and image data, email data, etc., and receives web data or streaming data, etc.

[0089] The display input unit 204 is a so-called touch panel that, under the control of the main control unit 220, displays images (still images and moving images) or text information to visually convey information to the user and detects user operations on the displayed information, and comprises a display panel 202 and an operation panel 203.

[0090] The display panel 202 uses LCD (Liquid Crystal Display), OELD (Organic Electro-Luminescence Display), etc., as display devices.

[0091] The operation panel 203 is a device that is visibly mounted on the display surface of the display panel 202 and detects one or more coordinates operated by the user's finger or stylus. When this device is operated by the user's finger or stylus, it outputs a detection signal generated by the operation to the main control unit 220. The main control unit 220 then detects the operation position (coordinates) on the display panel 202 based on the received detection signal.

[0092] As shown in Figure 10, the display panel 202 and operation panel 203 of the smartphone 200, which is illustrated as one embodiment of the imaging device of the present invention, together constitute a display input unit 204, but the operation panel 203 is positioned to completely cover the display panel 202.

[0093] When such an arrangement is adopted, the operation panel 203 may also be equipped with a function to detect user operations in areas outside the display panel 202. In other words, the operation panel 203 may be equipped with a detection area for the overlapping portion that overlaps with the display panel 202 (hereinafter referred to as the display area) and a detection area for the outer edge portion that does not overlap with the display panel 202 (hereinafter referred to as the non-display area).

[0094] The size of the display area and the size of the display panel 202 may be made to match perfectly, but it is not necessary for them to match. Furthermore, the operation panel 203 may have two sensitive areas: an outer edge portion and an inner portion. The width of the outer edge portion is designed appropriately according to the size of the housing 201, etc.

[0095] Furthermore, the position detection methods used in the control panel 203 include matrix switch methods, resistive film methods, surface acoustic wave methods, infrared methods, electromagnetic induction methods, and capacitive methods, and any of these methods can be adopted.

[0096] The communication unit 211 is equipped with a speaker 205 or a microphone 206, and converts the user's voice input through the microphone 206 into audio data that can be processed by the main control unit 220 and outputs it to the main control unit 220, or decodes audio data received by the wireless communication unit 210 or the external input / output unit 213 and outputs it from the speaker 205.

[0097] Furthermore, as shown in Figure 9, for example, the speaker 205 can be mounted on the same side as the display input unit 204, and the microphone 206 can be mounted on the side of the housing 201.

[0098] The operation unit 207 is a hardware key using a key switch or the like, which receives instructions from the user. For example, as shown in Figure 9, the operation unit 207 is mounted on the side of the casing 201 of the smartphone 200 and is a push-button type switch that turns on when pressed with a finger or the like, and turns off when the finger is released due to a restoring force such as a spring.

[0099] The memory unit 212 stores the control program and control data of the main control unit 220, application software, address data associated with the name or telephone number of the communication partner, sent and received email data, web data downloaded by web browsing, downloaded content data, and also temporarily stores streaming data. The memory unit 212 is composed of an internal memory unit 217 built into the smartphone and an external memory unit 218 with a removable external memory slot.

[0100] The internal storage units 217 and external storage units 218 that constitute the storage unit 212 are implemented using storage media such as flash memory type, hard disk type, multimedia card micro type, card type memory (for example, MicroSD® memory), RAM (Random Access Memory), and ROM (Read Only Memory).

[0101] The external input / output unit 213 serves as an interface for all external devices connected to the smartphone 200, and is intended for direct or indirect connection to other external devices via communication (e.g., Universal Serial Bus (USB), IEEE 1394, Bluetooth (registered trademark), RFID (Radio Frequency Identification), Infrared Data Association (IrDA) (registered trademark), UWB (Ultra Wideband) (registered trademark), ZigBee (registered trademark), etc.) or network (e.g., Ethernet (registered trademark), Wireless LAN (Local Area Network), etc.).

[0102] External devices that can be connected to the Smartphone 200 include, for example, wired / wireless headsets, wired / wireless external chargers, wired / wireless data ports, memory cards connected via card sockets, SIM (Subscriber Identity Module Card) / UIM (User Identity Module Card) cards, external audio / video equipment connected via audio / video I / O (Input / Output) terminals, wirelessly connected external audio / video equipment, wired / wireless connected smartphones, wired / wireless connected personal computers, wired / wireless connected personal computers, earphones, etc.

[0103] The external input / output unit 213 can transmit data received from such external devices to the various internal components of the smartphone 200, or enable data from inside the smartphone 200 to be transmitted to external devices.

[0104] The GNSS receiver 214 receives GNSS signals transmitted from GNSS satellites ST1 to STn in accordance with instructions from the main control unit 220, performs positioning calculation processing based on the received GNSS signals, and detects the position of the smartphone 200, consisting of its latitude, longitude, and altitude. When the GNSS receiver 214 can obtain position information from the wireless communication unit 210 or the external input / output unit 213 (for example, wireless LAN), it can also use that position information to detect the position.

[0105] The motion sensor unit 215 includes, for example, a 3-axis acceleration sensor, and detects the physical movement of the smartphone 200 according to the instructions of the main control unit 220. By detecting the physical movement of the smartphone 200, the direction of movement or acceleration of the smartphone 200 is detected. The detection results are output to the main control unit 220.

[0106] The power supply unit 216 supplies power stored in a battery (not shown) to each part of the smartphone 200 according to the instructions of the main control unit 220.

[0107] The main control unit 220 is equipped with a microprocessor and operates according to the control program and control data stored in the memory unit 212, and comprehensively controls each part of the smartphone 200. The microprocessor of the main control unit 220 has the same functions as the system control unit 11. In addition, the main control unit 220 is equipped with a mobile communication control function that controls each part of the communication system for voice communication or data communication via the wireless communication unit 210, and an application processing function.

[0108] The application processing function is realized by the operation of the main control unit 220 according to the application software stored in the memory unit 212. Examples of application processing functions include an infrared communication function that controls the external input / output unit 213 to communicate data with a counterpart device, an email function that sends and receives emails, and a web browsing function that displays web pages.

[0109] Furthermore, the main control unit 220 is equipped with image processing functions, such as displaying video on the display input unit 204 based on image data (still image or moving image data) such as received data or downloaded streaming data.

[0110] The image processing function refers to the function in which the main control unit 220 decodes the above image data, applies image processing to the decoded result, and displays the image on the display input unit 204.

[0111] Furthermore, the main control unit 220 performs display control for the display panel 202 and operation detection control to detect user operations through the operation unit 207 and the operation panel 203.

[0112] By executing display control, the main control unit 220 displays software keys such as icons or scroll bars for launching application software, or displays a window for composing an email.

[0113] A scroll bar is a software key that accepts commands to move the display portion of an image, such as a large image that does not fit within the display area of ​​the display panel 202.

[0114] Furthermore, by executing operation detection control, the main control unit 220 detects user operations through the operation unit 207, accepts operations on the icons and input of strings into the input fields of the windows through the operation panel 203, or accepts requests to scroll the displayed image through the scroll bar.

[0115] Furthermore, by executing operation detection control, the main control unit 220 determines whether the operation position on the operation panel 203 is in the overlapping portion (display area) that overlaps with the display panel 202 or in the outer edge portion (non-display area) that does not overlap with the display panel 202, and has a touch panel control function that controls the display position of the sensitive area of ​​the operation panel 203 or the software key.

[0116] Furthermore, the main control unit 220 can detect gesture operations on the operation panel 203 and execute pre-set functions in response to the detected gesture operations.

[0117] Gesture control refers to operations that differ from traditional simple touch operations, such as drawing a path with a finger or other object, specifying multiple locations simultaneously, or combining these to draw a path from at least one of multiple locations.

[0118] The camera unit 208 includes the lens device 40, image sensor 5, and digital signal processing unit 17 shown in Figure 1.

[0119] The image data generated by the camera unit 208 can be stored in the storage unit 212 or output via the external input / output unit 213 or the wireless communication unit 210.

[0120] In the smartphone 200 shown in Figure 10, the camera unit 208 is mounted on the same side as the display input unit 204, but the mounting position of the camera unit 208 is not limited to this, and it may also be mounted on the back of the display input unit 204.

[0121] Furthermore, the camera unit 208 can be used for various functions of the smartphone 200. For example, images acquired by the camera unit 208 can be displayed on the display panel 202, or images from the camera unit 208 can be used as one of the inputs for the operation panel 203.

[0122] Furthermore, when the GNSS receiver 214 detects a position, it can also detect the position by referring to the image from the camera unit 208. Moreover, by referring to the image from the camera unit 208, it is possible to determine the optical axis direction of the camera unit 208 of the smartphone 200, or to determine the current usage environment, either without using the 3-axis accelerometer or in combination with the 3-axis accelerometer. Of course, the image from the camera unit 208 can also be used within the application software.

[0123] In addition, position information acquired by the GNSS receiver 214, audio information acquired by the microphone 206 (which may be converted to text information by the main control unit, etc.), posture information acquired by the motion sensor unit 215, etc., can be added to still image or video image data and stored in the storage unit 212 or output through the external input / output unit 213 or the wireless communication unit 210. [Explanation of Symbols]

[0124] 1 imaging lens 2 apertures 4. Lens control unit 5 Image sensor 50 Light-shielding film 50W, 50R, 50L aperture RW, RR, RL light receiving area SR, SL light-shielding area Mainly CR, CL Lu, Ld virtual line G1, G2 gate electrodes HLE, HC, HRE range 8. Lens drive unit 9. Aperture drive unit 11 System Control Unit 14,207 Operation section 15 Memory Control Unit 16 memory 17 Digital signal processing unit 20 External memory control unit 21 Storage medium 22a Display Controller 22b Display surface 22 Display device 24 control bus 25 Data Bus 40 Lens device 60 Photosensitive area 61A Photoelectric conversion unit 61B Charge holding section 61C Charge Transfer Section 61D Floating Diffusion 61E Circuit 61 pixels 61W Standard Pixel 61R, 61L Pixels for phase-difference detection 62 pixel rows 63 Drive Circuit 64 Signal Processing Circuits 65 signal line 70 N-type substrate 71 P-well layer 72 electrode 73 N-type impurity layer 74 P-type impurity layer 75 areas 76 Transfer electrodes 77 Reset Transistor 78 Output transistors 79 Selective Transistors 100A Main Unit 100 Digital Cameras 200 Smartphones 201 cabinet 202 Display Panel 203 Control Panel 204 Display Input Section 205 Speakers 206 Microphone 208 Camera Department 210 Wireless Communication Section 211 Telephone section 212 Storage section 213 External input / output section 214 GNSS receiver 215 Motion sensor unit 216 Power supply section 217 Internal storage 218 External storage unit 220 Main Control Unit

Claims

1. An image sensor having a plurality of pixels arranged in a first direction and a second direction intersecting the first direction, The plurality of pixels include a photoelectric conversion unit, a charge holding unit to which the charge accumulated in the photoelectric conversion unit is transferred and held, and a voltage conversion unit to which the charge transferred from the charge holding unit is converted into a voltage. The photoelectric conversion unit and the charge holding unit are arranged side by side in the first direction. The charge holding unit and the voltage conversion unit are arranged side by side in the second direction. The plurality of pixels include the first pixel, The photoelectric conversion unit of the first pixel has a light-receiving region and a light-shielding region arranged in the second direction. An image sensor in which the width of the photoelectric conversion unit in the second direction is greater than the width of the charge holding unit in the second direction.

2. The image sensor according to claim 1, The second direction is the longitudinal direction of the image sensor.

3. The image sensor according to claim 1, An image sensor in which the charge held in the charge holding portion of one of the two first pixels arranged adjacent to each other in the second direction and the charge held in the charge holding portion of the other of the two first pixels are configured to be mixable in the charge holding portions of the two first pixels.

4. The image sensor according to claim 1, The first pixel includes a first type of pixel in which the light-receiving area is located on one side of the second direction and the light-shielding area is located on the other side of the second direction, and a second type of pixel in which the light-receiving area is located on the other side of the second direction and the light-shielding area is located on one side of the second direction. An image sensor in which, in the first type pixel and the second type pixel arranged adjacent to each other in the second direction, the light-receiving area of ​​the first type pixel and the light-receiving area of ​​the second type pixel are arranged between the light-shielding area of ​​the first type pixel and the light-shielding area of ​​the second type pixel.

5. The image sensor according to claim 4, The pair of first-type pixels and second-type pixels adjacent in the second direction includes the first pair, In the first pair, the boundary between the light-receiving regions is formed at an intermediate position between the center of the light-receiving region of the first type pixel and the center of the light-receiving region of the second type pixel.

6. The image sensor according to claim 4, The pair of the first type pixel and the second type pixel includes a second pair, In the second pair, the midpoint between the center of the light-receiving region of the first type pixel and the center of the light-receiving region of the second type pixel is eccentric toward the edge of the image sensor compared to the boundary between the light-receiving regions.

7. The image sensor according to claim 6, An image sensor in which the eccentricity of the intermediate position in the second pair increases as it approaches the edge of the image sensor.

8. An image sensor having a plurality of pixels arranged in a first direction and a second direction intersecting the first direction, The plurality of pixels include a photoelectric conversion unit, a charge holding unit to which the charge accumulated in the photoelectric conversion unit is transferred and held, and a voltage conversion unit to which the charge transferred from the charge holding unit is converted into a voltage. The photoelectric conversion unit and the charge holding unit are arranged side by side in the first direction. The charge holding unit and the voltage conversion unit are arranged side by side in the second direction. An image sensor in which the charge held in the charge holding portion of one of two pixels arranged adjacent to each other in a second direction intersecting the first direction, and the charge held in the charge holding portion of the other of the two pixels, are configured to be mixable in the charge holding portions of the two pixels.

9. An image sensor having a plurality of pixels arranged in a first direction and a second direction intersecting the first direction, The plurality of pixels include a photoelectric conversion unit, a charge holding unit to which the charge accumulated in the photoelectric conversion unit is transferred and held, and a voltage conversion unit to which the charge transferred from the charge holding unit is converted into a voltage. The photoelectric conversion unit and the charge holding unit are arranged side by side in the first direction. The charge holding unit and the voltage conversion unit are arranged side by side in the second direction. The plurality of pixels include the first pixel, The photoelectric conversion unit of the first pixel has a light-receiving region and a light-shielding region arranged in the second direction. The first pixel includes a first type of pixel in which the light-receiving area is located on one side of the second direction and the light-shielding area is located on the other side of the second direction, and a second type of pixel in which the light-receiving area is located on the other side of the second direction and the light-shielding area is located on one side of the second direction. An image sensor in which, in the first type pixel and the second type pixel arranged adjacent to each other in the second direction, the light-receiving area of ​​the first type pixel and the light-receiving area of ​​the second type pixel are arranged between the light-shielding area of ​​the first type pixel and the light-shielding area of ​​the second type pixel.

10. An imaging device comprising an image sensor according to any one of claims 1 to 9.

Images