JP6676393B2 - Solid-state imaging device and imaging device including the same - Google Patents

Description

  The present invention relates to a solid-state imaging device, and more particularly to a solid-state imaging device suitably used for an imaging device such as a digital camera.

  In recent years, there has been an increasing demand for an increase in the dynamic range of an image acquired by an imaging device such as a digital camera. To cope with this problem, in Patent Document 1, the aperture areas of a plurality of photoelectric conversion units provided in a pixel are made different from each other, the ratio of the amount of light incident on each of the photoelectric conversion units is changed, and a high sensitivity signal and a low sensitivity signal are compared. Two types of pixel signals are obtained. A technique has been proposed in which these are combined to expand the dynamic range of an image.

  There is also a growing demand for an imaging device that can acquire a still image signal while acquiring a moving image signal. Generally, in order to obtain a smooth moving image, it is preferable to perform shooting with an exposure time (charge accumulation time) substantially equal to the reading frame rate of the solid-state imaging device. On the other hand, in the case of a still image, it is preferable to set the exposure time according to the speed of movement of the subject. Therefore, in order to acquire a still image signal while acquiring a moving image signal, it is necessary to acquire two pixel signals having different exposure times.

  Patent Literature 2 includes a plurality of photoelectric conversion elements (corresponding to the photoelectric conversion unit in Patent Literature 1) in which one pixel has different exposure times in order to obtain a still image signal while obtaining a moving image signal. A solid-state imaging device has been disclosed. The area of the photoelectric conversion element with a relatively short exposure time is relatively large, and the area of the photoelectric conversion element with a relatively long exposure time is relatively small. Have different sensitivities.

  The “sensitivity of the photoelectric conversion element (photoelectric conversion unit)” is defined by the ratio of the amount of charge accumulated in the photoelectric conversion unit to the amount of light incident on the pixel per unit time.

  Further, Patent Document 3 discloses, as a conventional technique, a solid state device which includes a distance measuring pixel having a distance measuring function (hereinafter referred to as a distance measuring pixel) and can detect a distance to a subject by a phase difference method. An imaging device is disclosed. A plurality of photoelectric conversion units are provided in the distance measurement pixel, and light fluxes that have passed through different regions on the pupil of the photographing lens are respectively guided to different photoelectric conversion units. An image (hereinafter, referred to as distance measurement) based on a signal obtained by each of the plurality of photoelectric conversion units provided for each distance measurement pixel, based on a light beam that has passed through a pupil region shifted to the opposite side to the optical axis of the photographing lens. Image and description). Then, the distance to the subject can be detected by using the principle of triangulation based on the shift amount between the distance measurement images generated from the light beams that have passed through the different pupil regions of the photographing lens. At the time of imaging, an imaging signal can be obtained by adding and obtaining signal outputs obtained by a plurality of photoelectric conversion units in a pixel.

JP 2004-363193 A JP 2004-120391 A JP 2002-314062 A

  By the way, when acquiring a ranging image while acquiring images having different sensitivities, the following problems occur.

  In order to acquire one of a plurality of imaging signals having different sensitivities while acquiring the other using a method disclosed in Patent Document 1 or Patent Document 2, a plurality of photoelectric conversion units provided in a pixel are required. It is necessary to change the ratio of the amount of light incident on each of the sections. Specifically, two photoelectric conversion units are provided in the pixel, and the optical axis of the microlens is shifted from the center of the barrier region for separating the two photoelectric conversion units. However, when such an arrangement is employed, the distance (base line length) between the pupil regions of the photographing lens through which the light beam received by each photoelectric conversion unit passes decreases, and the distance measurement accuracy decreases.

  On the other hand, as in Patent Document 3, when the optical axis of the microlens passes through the center of the barrier region separating the two photoelectric conversion units, the light beam received by each of the plurality of photoelectric conversion units passes. Since the distance between the pupil regions (base line length) increases, the distance measurement accuracy increases. However, the amounts of light incident on the two photoelectric conversion units via the microlenses become substantially equal, and it becomes difficult to acquire one of a plurality of imaging signals having different sensitivities while acquiring the other.

  The present invention acquires a ranging signal (signal for acquiring a ranging image) while acquiring imaging signals (signals for acquiring images) having different sensitivities while preventing a decrease in ranging accuracy. The purpose is to make it possible.

The solid-state imaging device according to the present invention has a plurality of pixels, and for each of the plurality of pixels, a first photoelectric conversion region and a second photoelectric conversion region having different sensitivities are arranged in parallel in a first direction. A solid-state imaging device having the first photoelectric conversion region and a first barrier region sandwiched between the second photoelectric conversion regions, wherein the first photoelectric conversion region is in the first direction A first photoelectric conversion unit and a second photoelectric conversion unit for outputting signals for distance measurement arranged in parallel in a second direction intersecting with the first photoelectric conversion unit and the second photoelectric conversion unit A second barrier region interposed between the conversion units, the pixel has a microlens on the light incident side of the first photoelectric conversion region and the second photoelectric conversion region, and the second The optical axis of the microlens in one direction relative to the center of the first barrier region; Shift amount is, in the second direction, the larger than the deviation amount with respect to the center of the second barrier region of the optical axis of the microlens, the electrical size of the separation of the first barrier region, the It is characterized in that it is larger than the magnitude of the electrical isolation of the second barrier region.

  Furthermore, an image pickup apparatus according to the present invention includes a photographing lens and any one of the solid-state image pickup devices described above.

  According to the present invention, it is possible to acquire a ranging signal while acquiring imaging signals having different sensitivities while preventing a decrease in ranging accuracy.

FIG. 2 is a diagram illustrating an example of the solid-state imaging device according to the first embodiment. FIG. 2 is a diagram illustrating a configuration example of a pixel according to the first embodiment, and a diagram illustrating an example of a potential distribution provided in the pixel. FIG. 4 is a diagram illustrating angle dependence of sensitivity of a photoelectric conversion unit provided in a pixel according to the first embodiment. FIG. 5 is a diagram illustrating a modification of the microlens arranged in the pixel according to the first embodiment. FIG. 4 is a diagram illustrating an example in which microlenses having different refractive powers are arranged in pixels according to the first embodiment, and the angle dependence of the sensitivity of the second photoelectric conversion region in that case. FIG. 4 is a diagram illustrating a specific example in which microlenses having different refractive powers are arranged in pixels according to the first embodiment. FIG. 2 is a diagram illustrating a configuration example in which an optical waveguide is provided in a pixel according to the first embodiment, and the angle dependence of the sensitivity of the second photoelectric conversion region 122 in that case. FIG. 3 is a diagram illustrating an example of a potential distribution of first and second barrier regions provided in a pixel according to the first embodiment. FIG. 2 is a diagram illustrating an example of pixel arrangement in the solid-state imaging device according to the first embodiment; FIG. 9 is a diagram illustrating a configuration example of a pixel in a solid-state imaging device according to a second embodiment. FIG. 9 is a diagram illustrating a configuration example of a pixel in a solid-state imaging device according to a third embodiment. FIG. 14 is a diagram schematically illustrating an example of an imaging device including a solid-state imaging element according to a sixth embodiment. FIG. 7 is a diagram illustrating a configuration example of a pixel in a solid-state imaging device of a comparative example, and a relationship between sensitivity and a base line length of a photoelectric conversion unit provided in the pixel and a shift amount of an optical axis of a microlens. FIG. 4 is a diagram illustrating a state of propagation of a light beam incident on a pixel when a shift amount of an optical axis of a microlens is small and large. FIG. 4 is a diagram illustrating pixels in which a plurality of photoelectric conversion units for acquiring signals for distance measurement and a plurality of photoelectric conversion regions for acquiring imaging signals having different sensitivities are arranged in the same direction. FIG. 3 is a circuit diagram applicable to the pixels of the first and second embodiments. FIG. 11 is a diagram illustrating exposure times of a plurality of pixels arranged in the same column (when the first photoelectric conversion region has higher sensitivity than the second photoelectric conversion region). FIG. 7 is a diagram illustrating exposure times of a plurality of pixels arranged in the same column (when the first photoelectric conversion region has lower sensitivity than the second photoelectric conversion region).

  Hereinafter, an embodiment of a solid-state imaging device according to the present invention will be described with reference to the drawings. At this time, members having the same or corresponding functions are denoted by the same reference numerals in all the drawings, and repeated description will be omitted.

(Embodiment 1)
A configuration of a solid-state imaging device capable of simultaneously acquiring a ranging signal and a plurality of imaging signals having different sensitivities will be described.

  FIG. 1 is a schematic diagram illustrating an example of the solid-state imaging device 100 according to the present invention. The solid-state imaging device 100 has an imaging area 103 in which pixels are provided and an area in which a peripheral circuit 104 is arranged.

  The pixel 101 is a pixel arranged in the central area 102 of the imaging area 103. Here, the pixel arranged in the central region 102 is used to mean a pixel whose center of gravity of the pixel 101 is included in the central region 102 when viewed from a direction (Z direction) perpendicular to the imaging region 103. The central region 102 refers to a region whose distance from the center of the solid-state imaging device 100 is equal to or less than a predetermined value. The predetermined value is preferably equal to or less than a quarter of the length of the diagonal line of the imaging region 103, and more preferably equal to or less than one-twentieth of the length of the diagonal line.

  FIG. 1 shows an example of a solid-state imaging device in which 3 × 3 pixels 101 are arranged in the central region 102. However, the arrangement of the pixels 101 is not limited to this, and the central region 102 includes a plurality of pixels 101. I just need to have it. Further, the central region 102 may include a pixel having a different configuration from the pixel 101 in addition to the pixel 101.

  FIG. 2A is a diagram (XY plane) of the pixel 101 as viewed from the light incident side. FIG. 2B is a view (XZ sectional view) of a section taken along the broken line 2B-2B in FIG. 2A viewed from the Y direction, and FIG. 2C is a view taken along the broken line 2C-2C in FIG. It is the figure (YZ sectional view) which looked at the section from the X direction. The pixel 101 is provided with a microlens 110 and a substrate 120 from the light incident side (the pixel 101 has the microlens 110 on the light incident side of the substrate 120). The substrate 120 has a first photoelectric conversion region 121, a second photoelectric conversion region 122, and a first photoelectric conversion region sandwiched between the first photoelectric conversion region and the second photoelectric conversion region along the first direction. Are provided (parallel). In the case of FIG. 2, the first direction coincides with the Y direction in which pixels are arranged in the short direction of the solid-state imaging device.

  Further, in the first photoelectric conversion region 121, the first photoelectric conversion unit 123, the second photoelectric conversion unit 124, and the second photoelectric conversion unit 124 extend along the second direction that intersects the first direction on the surface of the substrate 120. A second barrier region 127 is provided (parallel) between one photoelectric conversion unit and the second photoelectric conversion unit. In the case of FIG. 2, the second direction coincides with the X direction in which pixels are arranged in the longitudinal direction of the solid-state imaging device. The second photoelectric conversion region 122 includes a single photoelectric conversion unit (122).

  In the pixel 101, a wiring 112 for setting an exposure time (charge accumulation time) of each photoelectric conversion unit and obtaining a signal generated by each photoelectric conversion unit is provided.

  The photoelectric conversion units 122, 123, and 124 are formed by forming a potential distribution by ion implantation or the like on a substrate 120 formed of a material such as silicon having absorption in a wavelength band to be detected. With a potential barrier formed by the potential distribution, a potential barrier is formed between the first photoelectric conversion region 121 and the second photoelectric conversion region 122, and becomes a first barrier region 125. Similarly, a potential barrier is also formed between the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 to form a second barrier region 127.

  FIG. 2D shows the potential distribution in the cross section of FIG. 2B, and FIG. 2E shows the potential distribution in the cross section of FIG. 2C. As shown in FIGS. 2D and 2E, the region including the maximum value of the potential barrier formed between the photoelectric conversion units and having a potential of 90% or more of the maximum value of the potential barrier is a barrier. Area.

  Note that in order to form a potential distribution in a pixel, ions may be implanted into a region corresponding to a barrier region instead of a region corresponding to a photoelectric conversion unit. Further, ion implantation may be performed on both the photoelectric conversion unit and the barrier region. In this case, it is preferable to implant ions having conductivity opposite to that of the ions implanted into the region corresponding to the photoelectric conversion unit into the barrier region.

  The shape of each photoelectric conversion region or photoelectric conversion unit in plan view may not be a rectangle as shown in FIG. 2A, and may be a circle, an ellipse, a polygon, or the like. The corners of the polygon may be rounded as formed in the manufacturing process.

  The microlenses 110 are provided to increase the light collection efficiency of light incident on the pixel 101 and to distribute the incident light to each photoelectric conversion unit. The microlens 110 is formed of an inorganic substance such as silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or BPSG, an organic substance such as a polymer or a resin, or a mixture thereof.

  The optical axis 111 of the microlens 110 is shifted from the center 126 of the first barrier region toward the first photoelectric conversion region (the −Y direction). The direction of deviation from the center 128 of the second barrier region with respect to the center 126 of the first barrier region is the Y direction. That is, the optical axis 111 of the microlens 110 is not shifted in the second direction (X direction) with respect to the center 126 of the first barrier region and the center 128 of the second barrier region. Here, “not shifted” means that a shift of about a manufacturing error is allowed. Specifically, a shift of about 5% of the width of the pixel in the second direction is allowed. The center of the first barrier region is used synonymously with the center of gravity of the region between the first photoelectric conversion region and the second photoelectric conversion region, and the shape of the first barrier region on the surface of the substrate 120 is defined as Z. It means the center of gravity of the figure when viewed in a plan view from the direction. The same applies to the center of the second barrier region.

  As described above, in the solid-state imaging device 100 shown in FIG. 2, the optical axis 111 of the microlens is not displaced in the X direction with respect to the center 128 of the second barrier region. Therefore, the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 receive the light beam that has passed through the pupil regions that are displaced in opposite directions (+ X direction and −X direction) with respect to the optical axis of the photographing lens. Thus, an electric signal is obtained. The image shift amount between the distance measurement image generated from the electric signal acquired by the first photoelectric conversion unit 123 and the distance measurement image generated from the signal acquired by the second photoelectric conversion unit 124 is calculated as follows. By calculating, the distance to the subject can be detected. That is, the signals obtained by each of the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 can be used as signals for distance measurement.

  Further, since the optical axis 111 of the microlens is arranged to be shifted from the center 126 of the first barrier region toward the first photoelectric conversion region 121, the amount of light incident on the first photoelectric conversion region 121 is Is larger than the amount of light incident on the photoelectric conversion region 122. That is, the sensitivity of the first photoelectric conversion region 121 is higher than the sensitivity of the second photoelectric conversion region 122. Accordingly, the sum of the electric signals generated by the first photoelectric conversion region 121, that is, the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124, is converted into a high-sensitivity signal, the second photoelectric conversion region, that is, the photoelectric conversion region. The electric signal generated by the conversion unit 122 can be used as a low-sensitivity signal.

  As described above, in the pixel 101, the second direction (X direction) in which the photoelectric conversion unit that acquires the signal for distance measurement is arranged, and the photoelectric conversion region that acquires signals having different sensitivities are arranged. The first direction (Y direction) crosses each other. Therefore, it is possible to realize a solid-state imaging device capable of simultaneously acquiring a signal required for distance measurement and a plurality of signals having different sensitivities required for imaging.

  Next, the present embodiment will be described in detail while comparing with a conventional solid-state imaging device.

  FIG. 13A is a configuration example of a pixel 1001 in a solid-state imaging device shown for comparison. FIG. 13A is a layout of the pixel 1001 viewed from the light incident side, and FIG. 13B is a view (XZ cross-sectional view) of a cross section taken along a dashed line 13B-13B in FIG. It is. The pixel 1001 includes a first photoelectric conversion unit 1021, a second photoelectric conversion unit 1022, a barrier region 1025, and a microlens 1010.

  FIG. 13C shows the relationship between the shift amount of the optical axis 1011 of the microlens in the X direction with respect to the center 1026 of the barrier region 1025 and the sensitivity ratio between the first photoelectric conversion unit 1021 and the second light conversion unit 1022. Is indicated by a two-dot chain line. When the optical axis 1011 of the microlens passes through the center 1026 of the barrier region, the shift amount is set to zero. The amount of displacement of the optical axis 1011 of the microlens in the X direction with respect to the center 1026 of the barrier region is determined while maintaining the arrangement of the microlens 1010 in the X direction of the openings of the first photoelectric conversion unit and the second photoelectric conversion unit. By changing the width, it can be easily adjusted.

  Sensitivity ratio = (sensitivity of first photoelectric conversion unit 1021) / (sensitivity of second photoelectric conversion unit 1022). As the value of the sensitivity ratio increases, the difference between the sensitivity of the first photoelectric conversion unit 1021 and the sensitivity of the second photoelectric conversion unit 1022 also increases.

  Further, FIG. 13C shows a distance measurement image generated from the signal obtained by the first photoelectric conversion unit 1021 and a distance measurement image generated from the signal obtained by the second photoelectric conversion unit 1022. The relationship between the base line length between them and the shift amount of the optical axis 1011 is indicated by a broken line. The base line length corresponds to the angle of incidence on the pixel between the light beams received by each of the first photoelectric conversion unit 1021 and the second photoelectric conversion unit 1022. The longer the base line length, the more accurate the distance measurement. It becomes possible.

  As can be seen from FIG. 13C, when the optical axis 1011 of the microlens passes through the center 1026 of the barrier region (shift amount = 0), the base line length is long, but the sensitivity ratio is small. On the other hand, if the amount by which the optical axis 1011 of the microlens is shifted toward the first photoelectric conversion unit 1021 (−X direction) from the center 1026 of the barrier region is increased, the sensitivity ratio increases but the base line length decreases. . Thus, in the conventional configuration, the sensitivity ratio and the base line length have a trade-off relationship.

  Next, the cause of this trade-off will be considered.

FIG. 14A shows the state of propagation of a light beam incident on the pixel 1001 when the shift amount of the optical axis 1011 of the micro lens 1010 with respect to the center 1026 of the barrier region is small, with respect to the XZ plane. As can be seen from the figure, the light flux indicated by the solid line and incident on the optical axis 1011 of the microlens at an angle + θ _(XZ) (+ X and −Z directions) is selectively guided to the photoelectric conversion unit 1022. A light flux indicated by a broken line and incident on the optical axis 1011 of the microlens at an angle −θ _(XZ) (−X and −Z directions) is selectively guided to the first photoelectric conversion unit 1021. Accordingly, the dashed light flux that has passed through the pupil region shifted in the + X direction with respect to the optical axis of the photographing lens has been selectively detected by the first photoelectric conversion unit 1021 and has passed through the pupil region shifted in the −X direction. The solid line luminous flux is selectively detected by the second photoelectric conversion unit 1022, and the base line length becomes longer.

  However, in the case of the pixel 1001 shown in FIG. 14A, the sizes of the incident angle ranges of the light beams received by the respective photoelectric conversion units are equal to each other, and the light amounts incident on the two photoelectric conversion units are also substantially equal. Therefore, the difference in sensitivity between the first photoelectric conversion unit 1021 and the second photoelectric conversion unit 1022 is reduced. Although it depends on the application, the sensitivity ratio of the sensitivity of the first photoelectric conversion unit to the sensitivity of the second photoelectric conversion unit is preferably at least twice.

  FIG. 14B shows the propagation state of a light beam incident on the pixel 1001 when the amount of displacement of the optical axis 1011 of the microlens with respect to the center 1026 of the barrier region is large, with respect to the XZ plane. As can be seen, most of the light incident on the pixel is guided to the first photoelectric conversion unit 1021. Accordingly, the sensitivity of the first photoelectric conversion unit 1021 is higher than the sensitivity of the second photoelectric conversion unit 1022, and the difference between the two sensitivities is large. However, at the same time, most of the light flux indicated by the broken line passing through the pupil area in the + X direction and the light flux indicated by the solid line passing through the pupil area in the −X direction are guided to the first photoelectric conversion unit 1021. The base line length becomes relatively short.

  Therefore, in the pixel 101 shown in FIG. 2, a direction (X direction) in which a photoelectric conversion unit for acquiring a signal for distance measurement is arranged and a direction in which a photoelectric conversion region for acquiring signals having different sensitivities are arranged. (Y direction) and cross each other. According to such a configuration, it is possible to realize a solid-state imaging device capable of simultaneously obtaining a distance measurement signal having a long base line length and a plurality of signals having different sensitivities having sufficient sensitivity differences.

  FIG. 3A shows the angle dependence of the first and second photoelectric conversion regions in the pixel 101 shown in FIG. FIG. 3A shows the sensitivities of the first photoelectric conversion region 121 and the second photoelectric conversion region 122 with respect to a light beam incident obliquely in the YZ plane. The sensitivity of the first photoelectric conversion region 121 means the sensitivity of the sum of the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124. FIG. 3A shows that the sensitivity of the first photoelectric conversion region 121 is higher than that of the second photoelectric conversion region 122 at almost all angles. Therefore, considering the entire light flux incident on the pixel, the sensitivity of the first photoelectric conversion region 121 is higher than that of the second photoelectric conversion region 122.

FIG. 3B shows the sensitivities of the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 with respect to a light beam incident obliquely in the XZ plane. The horizontal axis in FIG. 3B represents the angle of inclination in the + X and -Z directions as + θ _(XZ) and the angle inclining in the -X and -Z directions, with the incident angle of the light beam incident in the −Z direction being zero. −θ _(XZ) . From FIG. 3B, it is confirmed that light incident at an angle of + θ _(XZ) is selectively guided to the photoelectric conversion region 124 and light incident at an angle of −θ _(XZ) is selectively guided to the photoelectric conversion region 123. it can.

  FIG. 3C shows the sensitivity ratio and the base line length of the pixel 101 in the solid-state imaging device 100 according to the present embodiment together with the representative value of the pixel 1001 in the conventional solid-state imaging device 1000 in FIG. Is shown. In the pixel 101, the sensitivity ratio means a sensitivity ratio between the first photoelectric conversion region 121 and the second photoelectric conversion region 122 that have acquired signals having different sensitivities. The base length refers to the base length of the pupil region through which the light beam received by the first photoelectric conversion unit 123 passes and the pupil region through which the speed of light received by the second photoelectric conversion unit 124 passes. As a representative value of the pixel 1001 of the conventional solid-state imaging device, when the optical axis of the microlens and the center of the barrier region coincide with “conventional_displacement 0”, the optical axis of the microlens is set on the “conventional_displacement large”. (The value on the right side of FIG. 13C). In FIG. 13 (c), when the optical axis of the microlens is largely shifted from the center of the barrier region (right in FIG. 13 (c), the shift amount is large), even if the shift amount of the microlens is further increased. This is the case where the sensitivity ratio between the first photoelectric conversion unit and the second photoelectric conversion unit hardly changes.

  From the figure, it can be seen that when the present invention is used, a conventional solid-state imaging device having a small eccentricity can realize a base length equivalent to the base length of the pixel 1001 in the conventional solid-state imaging device when the eccentricity of the microlens is small, And a sensitivity ratio equivalent to that of the pixel 1001 in the solid-state imaging device.

  Up to this point, the optical axis 111 of the microlens is shifted in the first direction (Y direction) with respect to the center 126 of the first barrier region, and is shifted with respect to the center 128 of the second barrier region 127. The description has been given of the case in which there is no deviation in the two directions (X direction). However, the present invention is not limited to this condition. Specifically, the amount of deviation of the optical axis 111 of the microlens from the center 126 of the first barrier region in the first direction is different from that of the optical axis 111 of the microlens in the second direction. It suffices that the distance is larger than the shift amount from the center 128 of the region. If this condition is satisfied, a plurality of imaging signals having different sensitivities and a distance measurement signal can be simultaneously obtained.

  However, as shown in FIG. 2, the optical axis 111 of the microlens 110 is shifted in the first direction (Y direction) with respect to the center 126 of the barrier region 125, and is shifted to the center 128 of the second barrier region 127. On the other hand, it is preferable not to be displaced in the second direction (X direction). This is because the base line length between the ranging image generated from the signal obtained by the first photoelectric conversion unit and the ranging image obtained from the signal generated by the second photoelectric conversion unit can be the longest. .

  In FIG. 2, the position of the microlens 110 having a shape symmetrical with respect to a plane (XZ plane) passing through the optical axis 111 of the microlens 110 and perpendicular to the first direction (Y direction) is set at the center of the barrier region 125. The case where the microlens is decentered by shifting from 126 is shown. However, the invention is not limited to this example.

  FIG. 4 shows cross-sectional views corresponding to FIG. 2C for various modifications. In FIG. 4, the area of the first photoelectric conversion region and the opening area of the second photoelectric conversion region are almost equal, but may be different.

  FIG. 4A shows the optical axis of the microlens 110 by using a microlens including the optical axis of the microlens and having an asymmetric shape with respect to a plane perpendicular to the first direction (Y direction). 111 is a pixel 201 shifted from the center 126 of the first barrier region. FIG. 4B shows an optical axis of the microlens and an asymmetrical refractive index distribution with respect to a plane perpendicular to the first direction (Y direction) to effectively decenter the optical axis of the microlens. Pixel 202. In order to provide an asymmetric refractive index distribution, a layer forming a microlens may be formed of a plurality of materials, and an asymmetric distribution may be provided in a filling rate of a medium. Further, as in the pixel 203 shown in FIG. 4C, a part of the microlens may extend to an adjacent pixel.

  As shown in FIG. 2 and FIG. 4C, a configuration using a symmetrically shaped microlens 110 is preferable because the microlens can be easily manufactured. On the other hand, when an asymmetric lens shape or refractive index distribution is provided as shown in FIGS. 4A and 4B, the propagation of light incident on a pixel can be more precisely controlled by the lens shape or refractive index distribution. . Therefore, it is preferable because the sensitivity ratio between the first photoelectric conversion region 121 and the second photoelectric conversion region 122 can be increased, and the base line length between distance measurement images generated by signals can be increased.

  FIG. 5 shows a pixel 301 using a microlens having a different refractive power depending on the direction. Specifically, a photoelectric conversion region for obtaining a signal having a different sensitivity than the second direction (X direction) in which the photoelectric conversion units for receiving light beams from different pupil regions is disposed. A lens having a small refractive power in a first direction (Y direction) is disposed. 5A is a cross-sectional view corresponding to FIG. 2B, and FIG. 5B is a cross-sectional view corresponding to FIG. 2C. The configuration of FIG. 5 is preferable for the following reasons.

  As the refractive power of the microlens is larger, the influence of the imaging relationship by the microlens becomes stronger and the angle dependency of the sensitivity ratio becomes larger. Therefore, if a microlens having a large refractive power is used in the second direction (X direction) in which the photoelectric conversion unit for acquiring the signal for distance measurement is arranged, the first photoelectric conversion unit 123 and the second photoelectric conversion unit are used. This is preferable because the base line length of the distance measurement signal acquired by the conversion unit 124 can be increased. It is preferable that the focal point of the microlens 110 in the X direction coincides with the surface of the substrate 120 because the base line length can be particularly increased.

  On the other hand, in the first direction (Y direction) in which the first photoelectric conversion region 121 and the second photoelectric conversion region 122 are arranged to acquire signals having different sensitivities, the angle dependence of the sensitivity is small. Is more preferred. Because, when the angle dependence of the sensitivity is large, the first and second photoelectric conversion regions 121 and 122 receive only a light beam from a specific portion of the exit pupil region of the imaging lens to be used. This is because the blurred image of the subject deviated from the image is distorted. As a result, the quality of an image generated by combining the high-sensitivity signal and the low-sensitivity signal also deteriorates. Therefore, it is preferable to reduce the refractive power of the microlens in the first direction (Y direction) for acquiring signals of different sensitivities to reduce the angle dependence of the sensitivity.

FIG. 5C shows the dependence of the sensitivity of the second photoelectric conversion region 122 on the incident angle of the incident light beam with respect to the YZ plane, and the second photoelectric conversion in the pixel 101 in FIGS. 2A to 2C. This is shown together with the incident angle dependence of the sensitivity of the conversion region 122. The solid line in the drawing is the pixel 301 shown in FIGS. 5A and 5B (using a microlens having a smaller refractive power in the first direction than the second direction), and the broken line is in FIG. FIGS. 6A to 6C show the case of the pixel 101 shown in (a microlens having the same refractive power in the first direction and the second direction). From the figure, it can be seen that the use of a microlens having a smaller refractive power in the first direction than in the second direction makes it possible to apply a second lens, particularly for a light beam incident on a pixel at an angle range 140, that is, a large angle + θ _(YZ) . It can be seen that the angle dependence of the sensitivity of the photoelectric conversion region 122 can be reduced.

  If the refractive power in the Y direction is smaller than the refractive power in the X direction, as shown in the pixel 302 shown in FIGS. May be used. When a plurality of microlenses stacked in the Z direction is provided in the pixel, the refractive power of one of the microlenses in the X and Y directions may be changed, or the X and Y directions of both microlenses may be changed. The refractive power in the direction may be changed.

  Further, as a pixel 303 shown in FIGS. 6C and 6D, a digital lens that changes refractive power by changing a refractive index distribution depending on a direction may be used as a microlens. If a layer forming a digital lens is formed of a plurality of materials and a difference is provided in the filling rate of the medium between the X direction and the Y direction, the refractive power in the X direction and the Y direction can be controlled independently.

  Further, like the pixel 401 shown in FIGS. 7A to 7C, the optical waveguide 113 may be provided between the microlens 110 and the second photoelectric conversion region 122 and the photoelectric conversion units 123 and 124. good. 7A is a diagram showing a light incident surface (XY surface) of the pixel 101, FIG. 7B is a cross-sectional diagram (XZ cross-section) along a broken line 7B-7B in FIG. 7A, and FIG. It is sectional drawing (YZ cross section) in broken line 7C-7C of Fig.7 (a).

The provision of the optical waveguide 113 is preferable because the angle dependence of the sensitivity of the second photoelectric conversion region 122 with respect to a light beam incident obliquely on the YZ plane is reduced. FIG. 7D shows the angle dependence of the sensitivity of the second photoelectric conversion region 122 when the optical waveguide 113 is provided, together with the case where the optical waveguide is not provided. The solid line in the drawing indicates the case where the optical waveguide 113 is provided, and the broken line indicates the case where no optical waveguide is provided. From the figure, it can be seen that the provision of the optical waveguide 113 reduces the angle dependence of the sensitivity of the second photoelectric conversion region 122 with respect to a light beam incident on the angle range 140, that is, at a large angle + θ _(YZ) on the YZ plane. You can see that it is.

  The optical waveguide 113 includes a core 114 and a clad 115, and can be made of an inorganic substance such as silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or BPSG, or an organic substance such as a polymer or a resin. However, the combination of materials is selected such that the refractive index of the core 114 is larger than the refractive index of the cladding 115.

  As shown in FIGS. 7A to 7C, the center 116 of the exit end of the core 114 of the optical waveguide 113 is aligned with the center 126 of the first barrier region 125 with respect to the optical axis 111 of the microlens 110. It is preferable that they are shifted in the same direction as the above. With such a configuration, the difference in sensitivity between the first photoelectric conversion region 121 and the photoelectric conversion region 122 can be increased. Further, it is preferable that the center 116 of the emission end of the core 114 is not eccentric in the second direction (X direction) with respect to the center 128 of the second barrier region 127. With such a configuration, light from the pupil region can be selectively guided to each of the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124, and the base line length can be increased. .

  Therefore, when an optical waveguide is provided in the pixel, the amount of displacement of the center 116 of the exit end of the core with respect to the center 126 of the first barrier region in the first direction is different from the center 116 of the exit end with respect to the center 128 of the second barrier region. Is preferably larger than the shift amount in the second direction.

  Note that, like the microlens 110, a part of the core 114 of the optical waveguide may protrude into an adjacent pixel. However, the exit end of the core 114 does not protrude into an adjacent pixel. Also, when an optical waveguide is provided, microlenses having different refractive powers in the X direction and the Y direction may be used.

  The example of the so-called surface-illuminated solid-state imaging device in which the wiring 112 is arranged on the same side of the substrate as the microlens 110 has been described. However, the present invention may be applied to a so-called back-illuminated solid-state imaging device in which the wiring 112 is arranged on the side opposite to the microlens 110. In particular, when the pixel has the optical waveguide 113 as shown in FIG. 7, the wiring layout is restricted by the optical waveguide in the front-illuminated type, and therefore, the back-illuminated type is preferable.

  Further, in the pixel, the first direction in which the first photoelectric conversion region 121 and the second photoelectric conversion region 122 are arranged does not have to coincide with the Y direction in FIG. There may be. Similarly, the second direction in which the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 are arranged does not have to coincide with the X direction. May be. However, it is preferable that the angle between the first direction and the second direction is closer to 90 degrees, because the direction in which the light beam from the pupil region is obtained and the direction in which signals with different sensitivities are obtained can be separated. It is particularly preferable that the angle between the first direction and the second direction is 90 degrees (vertical), because the direction in which the light beam from the pupil region is obtained and the direction in which signals with different sensitivities are obtained are independent. Here, the case where the angle between the first direction and the second direction is 90 degrees (perpendicular) allows variations due to manufacturing errors. Specifically, the angle between the first direction and the second direction includes a range of 90 degrees ± 10 degrees.

  Further, it is preferable that the second direction coincides with the direction in which the pixels are arranged, since the sampling of the ranging image generated from the signal becomes finer and the detection accuracy of the image shift amount is improved. Therefore, as shown in FIG. 2, the first direction is the Y direction and the second direction is the X direction, or the first direction is the X direction and the second direction is the Y direction. Is most preferred.

  The potential distribution of the first barrier region 125 and the potential distribution of the second barrier region 127 may be determined independently.

  When there is charge crosstalk between the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 (hereinafter, “charge crosstalk” is also simply referred to as “crosstalk”), each photoelectric conversion is performed. The signal generated by the unit cannot be obtained separately. Therefore, when importance is attached to distance measurement accuracy, it is preferable that the magnitude of the electrical separation of the first barrier region 125 be larger than the magnitude of the electrical separation of the second barrier region 127.

  On the other hand, when acquiring signals of different sensitivities, the signal generated by the first photoelectric conversion unit 123 and the signal generated by the second photoelectric conversion unit 124 are added and used as a high-sensitivity signal. The presence of the talk does not change the magnitude of the high-sensitivity signal. On the other hand, when there is a crosstalk of charges between the first photoelectric conversion region 121 and the second photoelectric conversion region 122, the charge from the first photoelectric conversion region 121 having high sensitivity is converted into the charge having low sensitivity. It is diffused to the second photoelectric conversion region 122. Therefore, particularly, the magnitude of the low-sensitivity signal greatly changes. Therefore, when giving priority to images having different sensitivities, the magnitude of the electrical separation of the first barrier region 125 is made larger than the magnitude of the electrical separation of the second barrier region 127. Is more preferred.

  In particular, as the sensitivity difference between the photoelectric conversion units increases, the influence of the crosstalk between the photoelectric conversion units increases. Therefore, the magnitude of the electrical isolation of the first barrier region 125 is reduced by the second barrier region 127. It is preferable to make the size larger than the magnitude of the electrical separation. In order to increase the magnitude of the electrical isolation, the height of the potential barrier in the barrier region may be increased. Specifically, as shown in FIGS. 8A and 8B, the height of the potential barrier of the first barrier region 125 may be higher than the height of the potential barrier of the second barrier region 127. .

  Let φ be the height of the potential barrier when the bottom of the electron energy of the first photoelectric conversion region 121 and the second photoelectric conversion region 122 is the origin. Classically, electrons accumulated in the photoelectric conversion region follow the Boltzmann distribution, so that the charge density n over the potential barrier satisfies Equation 1 below. Here, e is the elementary charge, k is the Boltzmann constant, and T is the temperature of the photoelectric conversion unit.

  The crosstalk of the charge between the first photoelectric conversion region 121 and the second photoelectric conversion region 122 is 0.1% of the crosstalk of the charge between the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124. If it is less than twice, it can be said that the magnitude of the electrical isolation of the first barrier region 125 is larger than the magnitude of the electrical isolation of the second potential barrier 126.

Therefore, the height phi ₁ of the potential barrier of the first barrier region _125, when the height of the potential barrier of the second barrier region 127 and phi _2, it is preferable to satisfy Equation 2 below.

When the temperature of the photoelectric conversion unit is about 100 ° C., the difference phi ₁ and phi ₂ may if 74 [mV]. Note that Equation 2 is derived through the following process (Equation 3). And the first barrier region 125 and the charge density to overcome the potential barrier of the second barrier region 126 and n ₁ and n _2, respectively.

・・・（３）

... (3)

  Note that, as in the present invention, the direction in which the first photoelectric conversion region 121 and the second photoelectric conversion region 122 are arranged intersects with the direction in which the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 are arranged. In this case, a favorable effect can be obtained from the viewpoint of crosstalk between photoelectric conversion units. As in a pixel 1101 shown in FIG. 15, a first photoelectric conversion region 1021 and a second photoelectric conversion region 1022, a first photoelectric conversion portion 1023, and a second photoelectric conversion portion 1024 are arranged in the same direction. Explanation will be made in comparison with the case where 15A is a diagram (XY plane view) of the photoelectric conversion unit viewed from the light incident side, and FIG. 15B is a diagram of a cross section taken along a broken line 15B-15B in FIG. (XZ sectional view).

  In the case of the configuration illustrated in FIG. 15, the crosstalk between the second photoelectric conversion unit 1024 and the second photoelectric conversion region 1022 adjacent to each other is better than the first photoelectric conversion unit 1023 and the second photoelectric conversion region not adjacent to each other. It is greater than 1022 crosstalk. As a result, a sensitivity difference occurs between the first photoelectric conversion unit 1023 that is not affected by crosstalk and the second photoelectric conversion unit 1024 that is affected by crosstalk, and the distance measurement accuracy is reduced.

  In the present invention, the direction in which the first photoelectric conversion region 121 and the second photoelectric conversion region 122 are arranged and the direction in which the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 are arranged cross each other. Therefore, the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 are both adjacent to the second photoelectric conversion region, and the influence of crosstalk between the first photoelectric conversion unit 123 and the second photoelectric conversion region 122 is reduced. receive. Therefore, the effect of crosstalk between the first photoelectric conversion unit 123 and the second photoelectric conversion region 122 and the effect of crosstalk between the second photoelectric conversion unit 124 and the second photoelectric conversion region 122 Can be reduced. As a result, the sensitivity difference between the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 is reduced, and the distance measurement accuracy is improved.

  Furthermore, when the direction of arranging a plurality of photoelectric conversion units for acquiring signals of different sensitivities and the direction of arranging a plurality of photoelectric conversion units for acquiring a signal for distance measurement are crossed as in the present invention, The effect of increasing the speed of charge transfer from the photoelectric conversion unit can also be obtained.

  Like the pixel 1101 shown in FIG. 15, a first photoelectric conversion unit 1023 and a second photoelectric conversion unit 1024 for acquiring a signal for distance measurement, and a first photoelectric conversion unit 1024 for acquiring signals having different sensitivities from each other. Are compared with the case where the photoelectric conversion region 1021 and the second photoelectric conversion region 1022 are arranged in the same direction.

  Generally, a transfer electrode for transferring the charge generated in each photoelectric conversion unit to the peripheral circuit 104 is formed along an end of the photoelectric conversion unit. In the case of the configuration in FIG. 15, in order to obtain electric charge from the photoelectric conversion unit 1024 in which each of the long sides is close to another photoelectric conversion unit, a transfer electrode is provided along the short side. Become. As a result, the cross-sectional area of the channel of the transfer electrode is reduced, and the speed at which charges are transferred is reduced.

  On the other hand, in the pixel of the solid-state imaging device according to the present invention, the direction in which the first photoelectric conversion region 121 and the second photoelectric conversion region 122 are arranged, the first photoelectric conversion portion 123, and the second photoelectric conversion portion 124 and the direction in which they are arranged. Therefore, none of the photoelectric conversion units is sandwiched between the other photoelectric conversion units, so that a transfer electrode can be formed along any one of the three sides. In other words, the transfer electrode may be formed along the side having the largest cross-sectional area of the transfer channel among the three sides, and the speed at which charges are transferred can be improved.

  Although the configuration of one pixel has been described in detail, the arrangement of the photoelectric conversion unit, the barrier region, and the microlens may be different or the same between a plurality of pixels. As shown in FIG. 4C, when a part of the microlens 110 protrudes into an adjacent pixel, the arrangement as shown in FIG. This is preferable because the lens 110 can be arranged without interference. FIG. 9 shows a configuration of a plurality of pixels arranged in the central region 102 shown in FIG.

  FIG. 9A illustrates a case where the direction from the first photoelectric conversion region 121 to the second photoelectric conversion region 122 is the same + X direction among a plurality of pixels. FIG. 9B shows a case where the direction from the first photoelectric conversion region 121 to the second photoelectric conversion region 122 is reversed between pixels adjacent in the X direction.

  In addition, the direction from the first photoelectric conversion region 121 to the second photoelectric conversion region 122 may be different for each pixel from the X direction, the Y direction, and the oblique direction. Note that the direction from the first photoelectric conversion region to the second photoelectric conversion region means a direction from the center of gravity of the first photoelectric conversion region to the center of gravity of the second photoelectric conversion region.

(Embodiment 2)
FIGS. 10A to 10C are diagrams illustrating a configuration example of another pixel provided in a central region of the solid-state imaging device according to the second embodiment. The pixel 501 differs from the pixel 101 shown in FIG. 2 in that the shift direction of the optical axis 111 of the microlens 110 is opposite. That is, the optical axis 111 of the microlens 110 moves the second photoelectric conversion region with respect to the center 126 of the first barrier region 125 electrically separating the first photoelectric conversion region 121 and the second photoelectric conversion region 122. It is arranged to be shifted toward the conversion area 122 (+ Y direction) (see FIGS. 10A and 10C).

  Therefore, in the pixel 501, the sensitivity of the second photoelectric conversion region 122 is higher than the sensitivity of the first photoelectric conversion region 121. Therefore, in the case of the present embodiment, a signal obtained in the first photoelectric conversion region 121 is used as a low-sensitivity signal, and a signal obtained in the second photoelectric conversion region 121 is used as a high-sensitivity signal.

  As can be seen from Embodiment 1 and the present embodiment, in the present invention, if a high-sensitivity signal can be obtained on one of the first photoelectric conversion region and the second photoelectric conversion region, and a low-sensitivity signal can be obtained on the other. Good. Then, which photoelectric conversion region acquires the high-sensitivity signal or the low-sensitivity signal can be determined by the direction in which the optical axis 111 of the microlens is shifted.

  The optical axis 111 of the microlens 110 is shifted in the X direction with respect to the center 128 of the second barrier region 127, which electrically separates the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124. (See FIG. 10B). Therefore, the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 receive a light beam that has passed through a pupil region that is displaced on opposite sides (−X direction and + X direction) with respect to the optical axis of the photographing lens. Thus, a signal for distance measurement can be obtained.

  Thus, also in the solid-state imaging device according to the second embodiment, different pupils are provided by the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 arranged along the second direction (X direction). A signal for distance measurement is acquired from a light beam that has passed through the area. Then, of the first photoelectric conversion region 121 and the second photoelectric conversion region 122 arranged along the first direction (Y direction) intersecting with the second direction, the first photoelectric conversion region 121 is lower than the first photoelectric conversion region 121. A high sensitivity signal is obtained from the sensitivity signal and the second photoelectric conversion region 122. Note that the sum of the signals acquired by the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 corresponds to the low-sensitivity signal acquired by the first photoelectric conversion region 121. Various modifications can be applied to the solid-state imaging device 100 according to the second embodiment, similarly to the first embodiment.

(Embodiment 3)
FIG. 11 is a diagram illustrating a configuration example of another pixel provided in the central region of the solid-state imaging device according to the embodiment. The pixel 601 is different from the pixel 101 illustrated in FIG. 2 in that the third photoelectric conversion unit 131 and the fourth photoelectric conversion unit 132 arranged along the second direction (X direction) in the photoelectric conversion region 122 are different from each other. They differ in that they are provided.

  With such a configuration, even in the third photoelectric conversion unit 131 and the fourth photoelectric conversion unit 132, the pupil areas deviated from each other (−X direction and + X direction) with respect to the optical axis of the photographing lens. It is possible to receive the luminous flux that has passed through and obtain a signal for distance measurement. Therefore, distance measurement may be performed using the signals acquired by the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124, or may be acquired by the third photoelectric conversion unit 131 and the fourth photoelectric conversion unit 132. Distance measurement may be performed using the obtained signal. Alternatively, the reliability of the distance measurement result may be determined by comparing the two results.

(Embodiment 4)
In the present embodiment, an embodiment will be described in which a plurality of signals having different sensitivities acquired by a solid-state imaging device are used for expanding a dynamic range. In the case of this embodiment, a plurality of photoelectric conversion units having different sensitivities are driven at the same exposure time, a high-sensitivity signal and a low-sensitivity signal are obtained from each, and an image having a wide dynamic range is generated by combining them. I do.

  The second photoelectric conversion region 122 and the photoelectric conversion units 123 and 124 are driven by a signal transmitted from the peripheral circuit 104 of the solid-state imaging device 100 via the wiring 112 so that the exposure times of the two become equal. That is, the exposure time of the first photoelectric conversion unit 123 and the exposure time of the second photoelectric conversion unit 124 are equal, and the exposure time of the first photoelectric conversion region 121 and the exposure time of the second photoelectric conversion region 122 are also equal.

  If the amount of light incident on the pixel is below a certain threshold, use the high-sensitivity signal obtained in the first photoelectric conversion region, and if larger than the threshold, use the low-sensitivity signal obtained in the second photoelectric conversion region. By combining the two, an image having a wide dynamic range can be generated. The threshold value is set so as to be smaller than the signal intensity at which the high-sensitivity signal is saturated and larger than the signal intensity at which the low-sensitivity signal has a desired SN ratio.

Here, in order to expand the dynamic range by combining the high-sensitivity signal and the low-sensitivity signal, it is necessary to satisfy Expression 4 below. Here, the sensitivity of the first photoelectric conversion region 121 for acquiring a high-sensitivity signal is S1, the capacitance is C1, the sensitivity of the second photoelectric conversion region 122 for acquiring a low-sensitivity signal is S2, and the capacitance is C2. Note that, as described above, the sensitivity of the first photoelectric conversion region 121 means the sum of the sensitivities of the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124. Similarly, the capacity of the first photoelectric conversion region 121 means the sum of the capacities of the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124.
C1 / S1> C2 / S2 (4)

  Since C1 / S1 and C2 / S2 are the maximum light amounts that can be incident on the respective photoelectric conversion regions, when C1 / S1 ≦ C2 / S2, the light amount is equal to or less than the light amount at which the first photoelectric conversion region for acquiring a high-sensitivity signal is saturated. Therefore, the second photoelectric conversion region for acquiring a low-sensitivity signal is saturated. Therefore, it is necessary to control the values of C1, C2, S1, and S2 in advance so as to satisfy Equation 4.

  The ratio between S1 and S2 (sensitivity ratio between photoelectric conversion regions) can be controlled by changing the amount of displacement of the microlens 110 in the first direction, or by changing the size of each photoelectric conversion region or barrier region. .

  In order to increase the capacity of the photoelectric conversion region, the volume of the photoelectric conversion unit may be increased or the doping concentration of the photoelectric conversion unit may be increased. In order to increase the volume of the photoelectric conversion region, the area into which ions are implanted may be increased to increase the opening area of the photoelectric conversion portion, or the depth of the photoelectric conversion portion may be increased by implanting ions deeply. However, the depth and the doping concentration of the second photoelectric conversion region (third photoelectric conversion unit 131, fourth photoelectric conversion unit 132) 122, first photoelectric conversion unit 123, and second photoelectric conversion unit 124 are mutually different. It is preferable that the values be equal, since the respective photoelectric conversion portions can be formed under the same ion implantation conditions, so that the manufacturing process becomes easy.

(Embodiment 5)
In the present embodiment, a mode in which a plurality of signals having different sensitivities acquired by a solid-state imaging device are used to acquire a moving image and a still image will be described. In the case of the present embodiment, a plurality of photoelectric conversion units having different sensitivities are driven at different exposure times, and an image having a low sensitivity and a long exposure time and an image having a high sensitivity and a short exposure time are simultaneously obtained.

  Generally, the exposure time required to acquire a smooth moving image is often longer than the exposure time required to acquire a still image. Therefore, in the following, a signal acquired by the photoelectric conversion unit having a low sensitivity and a long exposure time will be described as a moving image, and a signal acquired by a high sensitivity and a photoelectric conversion unit with a short exposure time will be described as a still image. If the exposure time of the still image is required to be longer than the exposure time of the moving image, the signal obtained by the low-sensitivity and long-exposure time photoelectric conversion unit is used by the still image, high-sensitivity and short-exposure time photoelectric conversion unit. The acquired signal may be used for a moving image.

  In this embodiment, any of the solid-state imaging devices described in Embodiments 1 to 3 can be used. Here, the solid-state imaging device shown in FIG. 2 will be described as an example. If, as in the solid-state imaging device described in the second embodiment, the direction in which the optical axis of the microlens is shifted is opposite to that in FIG. 2, the signal acquired in the first photoelectric conversion region is used for moving images, The signals obtained in the two photoelectric conversion regions may be used for still images.

  In the present embodiment, driving is performed so that the exposure times of the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 are equal to each other and shorter than the exposure time of the second photoelectric conversion region 122. That is, the exposure time of the first photoelectric conversion area is shorter than the exposure time of the second photoelectric conversion area. Then, the still image is obtained from the sum of the signal obtained by the first photoelectric conversion unit 123 and the signal obtained by the second photoelectric conversion unit 124, that is, the second photoelectric conversion unit 121 A moving image is generated from the signal acquired in the conversion area 122. At the same time, the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 arranged along the second direction (X direction) are opposite to each other with respect to the optical axis of the photographing lens (−X direction and + X direction). The light flux passing through the pupil region deviated in the direction (direction) is received, and a signal for distance measurement is obtained.

  Subsequently, a modification specific to the solid-state imaging device according to the present embodiment will be described. Specifically, the sensitivity and capacity of the first photoelectric conversion region 121 and the second photoelectric conversion region 122 are described.

  In the fourth embodiment, one image with a wide dynamic range is generated by combining the signals acquired in the first photoelectric conversion area 121 and the second photoelectric conversion area 122. Therefore, it is necessary to satisfy Expression 4 between the first photoelectric conversion region 121 and the second photoelectric conversion region 122. However, in the solid-state imaging device according to the present embodiment, different images are generated from the signals acquired in the first photoelectric conversion region 121 and the second photoelectric conversion region 122, respectively. Therefore, it is preferable that the signal strength and the dynamic range of the still image signal and the moving image signal are as close as possible.

Specifically, it is most preferable to satisfy the following Expressions 5 and 6. In Equations 5 and 6, the sensitivity of the first photoelectric conversion region 121 for acquiring a signal for a still image is S1, the capacitance is C1, the exposure time is T1, and the second photoelectric conversion region 122 for acquiring a signal for a moving image is: The sensitivity is represented by S2, the capacity is represented by C2, and the exposure time is represented by T2. Equation 5 is a condition for signal strength, and Equation 6 is a condition for dynamic range.
S1 × T1 = S2 × T2 (5)
C1 / (S1 × T1) = C2 / (S2 × T2) (6)

  As described above, the ratio between S1 and S2 can be controlled by changing the amount of eccentricity of the optical waveguide or changing the size of each photoelectric conversion unit or barrier region. As can be seen from Expression 5, in the solid-state imaging device according to the present embodiment, the ratio between S1 and S2 may be determined assuming the exposure time of a still image and a moving image to be used. For example, assuming that the exposure time of a moving image is 1/60 second and the exposure time of a still image is 1/600 second, the pixel configuration may be determined so that S1 is 10 times S2. .

  From Equations 5 and 6, it is preferable that the capacities of the first photoelectric conversion region 121 and the second photoelectric conversion region 122 be equal. As described in the fourth embodiment, the capacity of the photoelectric conversion unit can be determined by the volume of the photoelectric conversion unit and the doping concentration of the photoelectric conversion unit.

  A case where the first photoelectric conversion region 121 and the second photoelectric conversion region 122 have the same capacity in the configuration of FIG. 2 will be described.

  For example, the length of the first photoelectric conversion unit and the length of the second photoelectric conversion unit in the first direction (Y direction) are longer than the length of the second photoelectric conversion region, and the length in the second direction (X direction) The case where the length of the first photoelectric conversion region and the length of the second photoelectric conversion region are the same is considered. In this case, in order to set C1 = C2, at least one of the doping depth and the doping concentration of the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 constituting the first photoelectric conversion region 121 is set to the second May be deeper or higher than the photoelectric conversion region 122.

  Next, a case where the doping concentration and the doping depth of the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 forming the first photoelectric conversion region 121 and the doping concentration of the second photoelectric conversion region 122 are the same will be considered.

  The first photoelectric conversion region 121 is provided with a second barrier region 127 for electrically separating the first photoelectric conversion unit and the second photoelectric conversion unit. On the other hand, the second photoelectric conversion region is constituted by a single photoelectric conversion unit, and has no barrier region. Therefore, when considering the capacity of the first photoelectric conversion region, it is necessary to consider that the length of the photoelectric conversion portion in the X direction is shorter than the length of the second photoelectric conversion region in the X direction. Therefore, the length of the first and second photoelectric conversion units in the Y direction is longer than the length of the second photoelectric conversion region in the Y direction, or the length of the first photoelectric conversion region in the X direction is By making the length longer than the two photoelectric conversion regions, C1 = C2 may be satisfied.

  However, as described above, when the depth and the doping concentration of the plurality of photoelectric conversion units are equal to each other, the plurality of photoelectric conversion units can be formed under the same ion implantation condition. preferable.

  As described above, any of the solid-state imaging devices described in Embodiments 1 to 3 can be used in the present invention. However, as shown in FIG. 2, among the first photoelectric conversion area and the second photoelectric conversion area, a plurality of photoelectric conversion units (for acquiring a signal for distance measurement) (the first photoelectric conversion unit and the If the first photoelectric conversion region including the second photoelectric conversion unit) has higher sensitivity than the second photoelectric conversion region, the distance measurement signal is acquired while acquiring imaging signals having different sensitivities from each other. This has the advantage that it can be performed at high speed. The following is a description.

  FIG. 16 is a circuit diagram applicable to the pixels 101, 201, 202, 203, 301, 302.303, 401, and 501 in the solid-state imaging device of the present invention. The circuit diagram shown in FIG. 16 is a circuit diagram of a signal acquisition circuit (readout circuit) called a 4Tr type, and the basic operation flow is the same as that of a general 4Tr type. However, it differs from a general 4Tr type in that a plurality of photoelectric conversion units are provided in one pixel. The signal detection operation will be described with reference to FIG.

  First, the reset transistors (RST) 175 and 176 and the transfer transistors (TX) 172, 173 and 174 are sequentially turned on by the horizontal drive line from the upper row of the solid-state imaging device (for example, see FIG. 1). Thus, the second photoelectric conversion region 122, the first photoelectric conversion unit 123, the second photoelectric conversion unit 124, and the in-pixel memories (FD) 181 and 182 connected thereto are reset. The FD 181 is shared by the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124, and the FD 182 is connected to the second photoelectric conversion region 122. Next, the TX 172, 173, and 174 are sequentially turned off from the upper row of the solid-state imaging device 100, and charge accumulation in the second photoelectric conversion region 122, the first photoelectric converter 123, and the second photoelectric converter 124 is performed. To start.

  During charge accumulation, a dark level signal for performing correlated double sampling is acquired in advance. Specifically, after turning off the RSTs 175 and 176, the selection transistors (SEL) 177 and 178 are turned on sequentially from the upper row of the solid-state imaging device 100, and the dark level signals of the FDs 181 and 182 are transmitted to the peripheral circuits. Forward.

  After the charge accumulation for a predetermined exposure time, a signal detection operation is performed. First, an operation of acquiring a pixel signal (voltage signal) based on the charge accumulated in the second photoelectric conversion region 122 will be described. The TX 172 is sequentially turned on from the upper row of the solid-state imaging device, and the charges accumulated in the second photoelectric conversion region 122 are transferred to the FD 182. After the TX 172 is turned off, the SEL 178 is turned on sequentially from the upper row of the solid-state imaging device to transfer the voltage signal to the peripheral circuit. In this case, the voltage signal transferred to the peripheral circuit is the sum of the voltage signal due to the charges transferred from the second photoelectric conversion region 122 to the FD 182 and the dark level signal. Therefore, the difference between the voltage signal (the sum of the pixel signal and the dark level signal) transferred to the peripheral circuit and the dark level signal previously transferred to the peripheral circuit is obtained, so that the second photoelectric conversion region 122 is obtained. , It is possible to acquire only the voltage signal based on the electric charge accumulated in the memory. In this manner, a voltage signal with low sensitivity and a long exposure time can be obtained.

  Next, two methods will be described for the operation of acquiring a voltage signal based on the charges accumulated in the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124. Either of the two methods may be used. Further, as will be described later, the two methods may be selectively used as two modes (a first mode and a second mode) according to the required ranging accuracy and image quality. The two modes may be automatically selected by a mode selection unit included in an imaging device (CPU 192) described later, or may be manually selected.

  The first method (first mode) is a method of separately acquiring voltage signals based on charges accumulated in the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124. The TX 173 is turned on sequentially from the upper row of the solid-state imaging device (see, for example, FIG. 1), and the charge accumulated in the first photoelectric conversion unit 123 is transferred to the FD 181. After the TX 173 is turned off, the SEL 177 is turned on sequentially from the upper row of the solid-state imaging device to transfer the voltage signal to the peripheral circuit. After that, by taking the difference between the voltage signal transferred to the peripheral circuit and the dark level signal, a voltage signal based on the electric charge accumulated in the first photoelectric conversion unit 123 is obtained.

  Subsequently, after the RST 175 is turned on to reset the charges stored in the FD 181, a signal based on the charges stored in the second photoelectric conversion unit 124 is obtained. Specifically, the TX 174 is turned on sequentially from the upper row of the solid-state imaging device, and the charges accumulated in the second photoelectric conversion unit 124 are transferred to the FD 181. After the TX 174 is turned off, the SEL 177 is turned on sequentially from the upper row of the solid-state imaging device to acquire a voltage signal. After that, by taking the difference between the read voltage signal and the dark level signal, a voltage signal based on the charge accumulated in the second photoelectric conversion unit 124 is obtained. The high-sensitivity and short-exposure-time voltage signal is obtained by calculating the sum of the voltage signal due to the charge accumulated in the first photoelectric conversion unit 123 and the voltage signal due to the charge accumulated in the second photoelectric conversion unit 124 as a It may be obtained by performing addition between voltage signals in a circuit.

  The second method (second mode) is a method of acquiring a signal based on a charge obtained by adding the charge stored in the first photoelectric conversion unit 123 and the charge stored in the second photoelectric conversion unit 124. . The second method is the same as the first method until a signal based on the charges accumulated in the first photoelectric conversion unit 123 is obtained. That is, from the upper row of the solid-state imaging device (for example, see FIG. 1), the TX 173 is sequentially turned on to transfer the charge accumulated in the first photoelectric conversion unit 123 to the FD 181. After the TX 173 is turned off, the SEL 177 is turned on sequentially from the upper row of the solid-state imaging device to acquire a voltage signal. After that, by taking the difference between the read voltage signal and the dark level signal, a voltage signal based on the charges accumulated in the first photoelectric conversion unit 123 is obtained.

  Subsequently, the TX 174 is turned on while the RST 175 is turned off, and the charge accumulated in the second photoelectric conversion unit 124 is transferred to the FD 181. In this case, the FD 181 stores a charge obtained by adding the charge stored in the first photoelectric conversion unit 123 and the charge stored in the second photoelectric conversion unit 124. Therefore, the SEL 177 is turned ON from the upper row of the solid-state imaging device to acquire a voltage signal. Thereafter, by taking the difference between the read voltage signal and the dark level signal, the charge stored in the first photoelectric conversion unit 123 and the charge stored in the second photoelectric conversion unit 124 are added. A signal based on charges can be obtained. However, in the second method, it is not possible to directly obtain a signal based on the charge accumulated in the second photoelectric conversion unit 124. Therefore, a voltage signal based on the charge obtained by adding the charge stored in the first photoelectric conversion unit 123 and the charge stored in the second photoelectric conversion unit 124 and a voltage signal based on the charge stored in the second photoelectric conversion unit 124 The difference between the two signals may be obtained by subtraction between the two voltage signals in the peripheral circuit.

  In the first method, a signal for distance measurement is directly obtained, while a signal for a captured image is obtained by adding two voltage signals. On the other hand, in the second method, a signal for a captured image is directly obtained, and one of the signals for distance measurement is obtained by subtraction between voltage signals. Generally, by performing addition and subtraction between two voltage signals, the SN of the signal is reduced. Therefore, the first method has higher quality of a signal for distance measurement, and the second method has higher quality. The signal quality for the captured image is high. Therefore, when the required ranging accuracy is high, it is preferable to use the first method, and when the required image quality is high, it is preferable to use the second method. Note that, in the above example, the case where the charge accumulated in the first photoelectric conversion unit 123 is transferred to the FD first, but the charge accumulated in the second photoelectric conversion unit 124 is first transferred to the FD. You may transfer it.

  The exposure time (charge accumulation time) of the second photoelectric conversion region 122 is a time from when the TX 172 is turned off to when it is turned on. Similarly, the exposure time (charge accumulation time) of the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 is the time from when TX 173 is turned off to when it is turned on, and when TX 174 is turned off. It is the time from turning on to turning on. In the fifth embodiment, the exposure times of the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 are equal.

  FIGS. 17 and 18 show exposure times of a plurality of pixels arranged in the same column. FIG. 17 shows that the first photoelectric conversion region (provided with the first photoelectric conversion unit and the second photoelectric conversion unit) is larger than the second photoelectric conversion region (122a,..., 122f). FIG. 18 shows a case where the sensitivity is high, and FIG. 18 shows a case where the sensitivity of the first photoelectric conversion region is lower than that of the second photoelectric conversion region (the pixel 501 shown in FIG. When it is arranged). FIGS. 17 and 18 differ in the relationship of the exposure time between the first photoelectric conversion region and the second photoelectric conversion region because the sensitivity relationship is different.

  As can be seen from FIG. 17, FIG. 17 has a shorter time to acquire the distance measurement signal and the captured image signal than FIG. The reason can be understood as follows.

  As described above, the signal read out from the signal line connected to the FD 181 includes the signal based on the charge accumulated in the first photoelectric conversion unit 123 (123a,..., 123f) and the second photoelectric conversion unit 124. (124a,..., 124f). On the other hand, a signal read out from a signal line connected to the FD 182 is only one type of a signal due to charges accumulated in the second photoelectric conversion region 122. Therefore, the read time of the signal line connected to the FD 181 is longer than the read time of the signal line connected to the FD 182, and is almost twice the read time of the signal line connected to the FD 182. Note that if the signal based on the electric charge stored in the first photoelectric conversion unit 123 and the signal based on the electric charge stored in the second photoelectric conversion unit 124 are read out using separate signal lines, the reading time will be short. As a result, the number of necessary transistors and signal lines increases. As a result, there are disadvantages such as a decrease in the aperture ratio of the photoelectric conversion unit and an increase in the cost required for manufacturing.

  As shown in FIG. 17, when the exposure time of the first photoelectric conversion region is shorter than the exposure time of the second photoelectric conversion region 122, the exposure of the second photoelectric conversion region 122 is completed before the exposure is completed. In addition, a time-consuming operation of reading signals from the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 can be performed in advance. Therefore, the time for acquiring the voltage signal can be shortened. On the other hand, as shown in FIG. 18, when the exposure time of the first photoelectric conversion region is longer than the exposure time of the second photoelectric conversion region 122, the exposure of the second photoelectric conversion region 122 ends. After that, it is necessary to perform a time-consuming signal read operation from the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124. Therefore, the time for acquiring the voltage signal becomes long.

  As described above, when the exposure time of the first photoelectric conversion region is shorter than the exposure time of the second photoelectric conversion region 122, the time for acquiring a signal can be shorter. That is, as shown in FIG. 2, when the first photoelectric conversion region including a plurality of photoelectric conversion units for acquiring a signal for distance measurement has higher sensitivity than the second photoelectric conversion region, In addition, it is possible to acquire a ranging signal at a high speed while acquiring imaging signals having different sensitivities.

  When acquiring a moving image from the first photoelectric conversion region and a still image from the second photoelectric conversion region, the time for acquiring a signal is shortened, and the continuous shooting speed for acquiring a still image can be improved. There is an advantage that it can be done. When a still image is obtained from the first photoelectric conversion region and a moving image is obtained from the second photoelectric conversion region, the frame rate of the moving image can be improved by shortening the time for obtaining a signal. The merit arises.

  In particular, when the exposure time of the first photoelectric conversion region is equal to or less than half of the exposure time of the second photoelectric conversion region, the exposure and reading of the first photoelectric conversion unit during the exposure of the second photoelectric conversion region are performed. It is more preferable because the operation can be completed.

(Embodiment 6)
FIG. 12 is a schematic diagram of an imaging device 190 including the solid-state imaging device 100 according to the present invention. The imaging device 190 includes a housing 197 having a lens mounting portion 196 for mounting the photographing lens 191. The housing 197 includes the solid-state imaging device 100 and a control unit 198 that controls the operation of the imaging device 190. I have. Then, the photographing lens 191 is attached to the housing 197 at the lens attaching portion 196. The imaging device 190 may have a configuration in which the imaging lens 191 can be removed from the housing 197 and replaced, or a configuration in which the imaging lens 191 cannot be replaced. The control unit includes a CPU 192, a transfer circuit 193, a signal processing unit 194, and an element driving circuit 195.

  The CPU 192 is a circuit that controls the transfer circuit 193, the signal processing unit 194, and the element driving circuit 195. The element driving circuit 195 is a circuit that drives the solid-state imaging device 100 in response to a signal from the CPU 192. For example, the exposure time of a photoelectric conversion unit provided in each pixel and the timing of reading a signal acquired by the photoelectric conversion unit And so on. The transfer circuit 193 stores the signal read from the solid-state imaging device 100 or transfers the signal to the signal processing unit 194. The signal processing unit 194 performs image processing of a signal obtained via the transfer circuit 193.

  The solid-state imaging device 100 outputs a signal obtained by each of the first photoelectric conversion unit 123, the second photoelectric conversion unit 124, and the second photoelectric conversion region 122 to the transmission circuit 193, and outputs the signal to the transmission circuit 193. The transmitted signal is transmitted to the signal processing unit 194.

  The signal processing unit 194 receives the signal from the CPU 192, detects the distance to the subject, and generates an image of the subject from the signal acquired by each photoelectric conversion unit. Here, an imaging apparatus including a solid-state imaging device including the pixels 101 in FIG. 2 will be described as an example.

  First, a case where the CPU 192 outputs a signal for generating an image having a wide dynamic range will be described.

  In this case, the element driving circuit 195 operates such that the exposure times of the first photoelectric conversion unit 123, the second photoelectric conversion unit 124, and the second photoelectric conversion region 122 are equal to each other.

  The signal processing unit 194 adds the signal obtained by the first photoelectric conversion unit 123 and the signal obtained by the second photoelectric conversion unit 124 to obtain a high-sensitivity signal. Then, it is obtained as a low-sensitivity signal obtained in the second photoelectric conversion region 122. If the amount of light incident on the pixel is below a predetermined threshold, a high-sensitivity signal is used, and if it is above the threshold, a low-sensitivity signal is used to combine the two to form an image with a wide dynamic range. I do. Further, the signal processing unit 194 compares the distance measurement image generated from the signal obtained by the first photoelectric conversion unit 123 with the distance measurement image generated from the signal obtained by the second photoelectric conversion unit 124, and Calculate the distance to.

  Next, a case where the CPU 192 outputs a signal for simultaneously generating a moving image and a still image will be described.

  In this case, the element driving circuit 195 operates such that the exposure time of the first photoelectric conversion unit 123 and the second photoelectric conversion unit 124 is shorter than the exposure time of the second photoelectric conversion region 122.

  The signal processing unit 194 adds the signal obtained by the first photoelectric conversion unit 123 and the signal obtained by the second photoelectric conversion unit 124 to obtain a high-sensitivity signal. Then, it is obtained as a low-sensitivity signal obtained in the second photoelectric conversion region 122. Then, a still image is generated from the high-sensitivity signal, and a moving image is generated from the low-sensitivity signal. Further, the signal processing unit 194 compares the distance measurement image generated from the signal obtained by the first photoelectric conversion unit 123 with the distance measurement image generated from the signal obtained by the second photoelectric conversion unit 124, and Calculate the distance to. In addition, autofocus may be performed by the imaging device 190 using the calculated distance. In this case, the distance to the subject can be calculated without lowering the frame rate at which a moving image is acquired by acquiring the ranging image together with the still image by the photoelectric conversion unit having high sensitivity and short exposure time.

  In addition, the imaging device 190 has a dynamic range expansion mode for forming an image with a wide dynamic range, and a moving and still image simultaneous acquisition mode for simultaneously acquiring a moving image and a still image, and the user can select either one. Device may be used. The CPU 192 outputs a signal for generating an image with a wide dynamic range when the dynamic range expansion mode is selected, and a signal for simultaneously generating a moving image and a still image when the simultaneous moving and still image acquisition mode is selected. Is output. These two modes may be automatically selected by a mode selection unit included in the imaging device (CPU 192), or may be manually selected.

  When the dynamic range expansion mode is selected, the signal processing unit 194 uses a relatively sensitive signal when the amount of light incident on the pixel is equal to or less than a predetermined threshold, and when the amount of light incident on the pixel is smaller than the predetermined threshold, An image of the subject is generated using a relatively insensitive signal. On the other hand, when the moving and still image simultaneous acquisition mode is selected, the signal processing unit 194 generates one of a still image and a moving image with the signal acquired in the first photoelectric conversion region, and generates the other image. The signal is generated based on the signal obtained by the second photoelectric conversion unit.

  As described above, when the imaging device 190 has the dynamic range expansion mode and the moving and still image simultaneous acquisition mode, the solid-state imaging device needs to have a configuration suitable for both applications. Therefore, the sensitivity and the capacity of each of the first photoelectric conversion region 121 and the second photoelectric conversion region 122 are designed to satisfy at least Equation 4. Furthermore, it is more preferable that Expressions 5 and 6 are satisfied.

100, 1000 solid-state imaging device 101 pixel 201, 202, 203 pixel 301, 302, 303 pixel 401 pixel 501 pixel 601 pixel 1001 pixel 102 central region 110, 1010 microlens 111, 1011 optical axis of microlens 112 wiring 113 optical waveguide 114 Core 115 Cladding 116 Center of emission end of core 120 Substrate 121 First photoelectric conversion region 122 Second photoelectric conversion region (photoelectric conversion unit)
123 first photoelectric conversion unit 124 second photoelectric conversion unit 125 first barrier region 126 center of first barrier region 127 second barrier region 128 center of second barrier region 190 imaging device 191 imaging lens 192 CPU
193 transfer circuit 194 signal processing unit

Claims (12)

Having a plurality of pixels, for each of the plurality of pixels, arranged in parallel in a first direction, the first photoelectric conversion region and the second photoelectric conversion region having mutually different sensitivities, and the first photoelectric conversion region A first barrier region sandwiched between the second photoelectric conversion region, and a solid-state imaging device,
The first photoelectric conversion region, a first photoelectric conversion unit and a second photoelectric conversion unit for outputting a signal for distance measurement arranged in parallel in a second direction intersecting the first direction, Including the first photoelectric conversion unit and a second barrier region sandwiched between the second photoelectric conversion unit,
The pixel has a microlens on the light incident side of the first photoelectric conversion region and the second photoelectric conversion region, and in the first direction, the first of the optical axis of the microlens The shift amount with respect to the center of the barrier region is larger than the shift amount of the optical axis of the microlens with respect to the center of the second barrier region in the second direction,
A solid-state imaging device, wherein the magnitude of the electrical separation of the first barrier region is larger than the magnitude of the electrical separation of the second barrier region.   Since the height of the potential barrier of the first barrier region is higher than the height of the potential barrier of the second barrier region, the magnitude of the electrical isolation of the first barrier region is 2. The solid-state imaging device according to claim 1, wherein the magnitude of the electrical isolation of the barrier region is larger than that of the solid-state imaging device.   Among the first photoelectric conversion region and the second photoelectric conversion region, the first photoelectric conversion region has a relatively high sensitivity, and the second photoelectric conversion region has a relatively low sensitivity. The solid-state imaging device according to claim 1.   4. The solid-state imaging device according to claim 1, wherein an angle between the first direction and the second direction is perpendicular. 5. The pixel has a microlens on the light incident side of the first photoelectric conversion region and the second photoelectric conversion region,
5. The microlens according to claim 1, wherein the microlens includes an optical axis of the microlens and has an asymmetric shape with respect to a plane perpendicular to the first direction. 6. Solid-state imaging device. The pixel has a microlens on the light incident side of the first photoelectric conversion region and the second photoelectric conversion region,
5. The microlens according to claim 1, wherein the microlens includes an optical axis of the microlens and has an asymmetric refractive index distribution with respect to a plane perpendicular to the first direction. 6. The solid-state imaging device according to any one of the preceding claims. The pixel has a microlens on the light incident side of the first photoelectric conversion region and the second photoelectric conversion region,
The solid-state imaging device according to claim 1, wherein a refractive power of the micro lens in the first direction is smaller than a refractive power in the second direction. The pixel has a microlens on the light incident side of the first photoelectric conversion region and the second photoelectric conversion region, and an optical waveguide on the light emission side of the microlens,
In the first direction, the shift amount of the center of the emission end of the core of the optical waveguide with respect to the center of the first barrier region is in the second direction, the center of the emission end of the core of the optical waveguide, The solid-state imaging device according to any one of claims 1 to 7, wherein the difference is larger than a shift amount from a center of the second barrier region.   The method according to claim 1, wherein the second photoelectric conversion region includes a third photoelectric conversion unit and a fourth photoelectric conversion unit arranged in parallel in the second direction. 20. The solid-state imaging device according to claim 20.   The solid-state imaging device according to claim 1, wherein a charge accumulation time of the first photoelectric conversion region is equal to or less than half of a charge accumulation time of the second photoelectric conversion region. A shooting lens,
An imaging apparatus comprising: the solid-state imaging device according to claim 1. The first mode, the second mode, having a mode selection unit that can select,
When the first mode is selected by the mode selection unit, a signal based on a charge obtained by adding the charge stored in the first photoelectric conversion unit and the charge stored in the second photoelectric conversion unit is used. Acquired,
When the second mode is selected by the mode selection unit, a signal based on the charge stored in the first photoelectric conversion unit and a signal based on the charge stored in the second photoelectric conversion unit are separately obtained. The imaging device according to claim 11, wherein:

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