JP2020088029A - Imaging element and imaging apparatus - Google Patents

Abstract

An imaging device having high photodetection sensitivity and an imaging device using the same are provided. Kind Code: A1 An image pickup device in which a plurality of image pickup pixels are arranged two-dimensionally, wherein each of the plurality of image pickup pixels includes a plurality of electrically divided photoelectric conversion units, a microlens, and the photoelectric conversion. and a light shielding wall surrounding the imaging pixel between the portion and the microlens, wherein the width of the surface of the light shielding wall on the microlens side is larger than the width of the surface of the light shielding wall on the photoelectric conversion unit side. It is characterized by [Selection drawing] Fig. 2

Description

The present invention particularly relates to an image pickup device and an image pickup apparatus for performing phase difference detection by pupil division.

2. Description of the Related Art In an image pickup apparatus such as a digital camera or a digital video camera that images a scene by forming light from a subject on an image pickup element in which image pickup pixels are two-dimensionally arranged, in recent years, the pixel size has been reduced by increasing the number of pixels and It is important to improve the photodetection sensitivity. In particular, there are many image pickup devices that perform focus detection by an image pickup surface phase difference method that performs phase difference detection by dividing the pupil of the imaging optical system, and it is important to guide light incident on a pixel to a photoelectric conversion unit with high sensitivity. .. Therefore, various proposals have been made in order to obtain an image pickup device having high light detection sensitivity.

In Patent Document 1, in order to prevent sensitivity deterioration due to light leakage between pixels, color mixture between pixels, and phase loss information from being lost, an optical waveguide is shielded so as to surround each pixel. Pixel configurations that introduce walls have been proposed. Patent Document 2 discloses a configuration in which an optical waveguide is formed from the vicinity of the surface of a photoelectric conversion unit to the upper end of an insulating film, and light incident on a pixel is scattered and absorbed by wiring inside the pixel, resulting in loss. I'm trying to avoid that.

Furthermore, as the pixel size is reduced due to the increase in the number of pixels, it has become difficult to efficiently introduce light into a narrow light receiving region as the wavelength of light increases. As means for dealing with such a current situation, Patent Document 3 proposes a configuration in which the refractive index of the antireflection film on the bottom surface of the optical waveguide of the pixel corresponding to each color is adjusted to suppress variations in light receiving sensitivity between colors. Has been done.

JP, 2005-167219, A JP, 2005-162562, A JP, 2005-69992, A

However, light may leak from the peripheral portion of the pixel or from an adjacent pixel, which may disturb the electromagnetic field distribution in the pixel or change the light receiving efficiency depending on the color as the pixel size is reduced. In such a case, the focus detection accuracy in the imaging plane phase difference method is deteriorated.

In view of the above problems, it is an object of the present invention to provide an image pickup device having high photodetection sensitivity and an image pickup apparatus using the same.

The image pickup device according to the present invention is an image pickup device in which a plurality of image pickup pixels are two-dimensionally arranged, and each of the plurality of image pickup pixels includes a plurality of electrically divided photoelectric conversion units, a microlens, and A light-shielding wall that surrounds the imaging pixel between the photoelectric conversion unit and the microlens, and a width of a surface of the light-shielding wall on the microlens side is equal to a width of a surface of the light-shielding wall on the photoelectric conversion unit side. Characterized by being larger than the width.

According to the present invention, it is possible to provide an image pickup element having high photodetection sensitivity, which enhances focus detection accuracy by an image pickup surface phase difference method, and an image pickup apparatus using the same.

It is a schematic diagram showing an image sensor and a basic pixel group of 2 rows and 2 columns which is a part thereof. It is a schematic diagram showing the cross section of the imaging pixel in 1st Embodiment. It is a figure for demonstrating the detailed shape of the shading wall between pixels. It is a figure for explaining other examples of a shading wall between pixels. It is a figure for demonstrating the gap of a top micro lens. It is the schematic which showed the correspondence of an image sensor and pupil division. It is a figure for explaining the outline of the relation between the amount of image shifts between parallax images, and the amount of defocus. It is a block diagram which shows the internal structural example of an imaging device. It is a schematic diagram showing the cross section of the image pick-up pixel which has the area|region of the edge part in an optical waveguide. It is a schematic diagram showing the cross section of the imaging pixel which has the area|region of the edge part in an optical waveguide in the image surface position away from the center position. It is a schematic diagram showing the cross section of the imaging pixel in 2nd Embodiment. It is a figure for explaining a propagation path of light which enters into a pixel with and without a shade part. It is a schematic diagram showing the cross section of the imaging pixel in 3rd Embodiment. It is a block diagram which shows the internal structural example of an imaging device. It is a schematic diagram showing a basic pixel group of RGB pixels. It is a figure for demonstrating the cross section of an imaging pixel, and the propagation path of light. It is a figure for explaining the outline of the corresponding relation between a pixel structure and pupil division. It is a figure for demonstrating the beam waist radius of light. It is a figure for demonstrating the direction where crosstalk arises between R pixel, G pixel, and B pixel.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. In the present embodiment, an example will be described in which the effective pixel area has a horizontal size of 22.32 mm, a vertical size of 14.88 mm, a horizontal effective pixel count of 6000, and a vertical effective pixel count of 4000.

FIG. 1A is a schematic diagram showing a basic pixel group 101 of 2 rows and 2 columns as a part of a plurality of imaging pixels arranged on an imaging surface of an imaging device. The basic pixel group 101 includes an imaging pixel 102 having spectral sensitivity in a wavelength band corresponding to red, an imaging pixel 103 having spectral sensitivity in a wavelength band corresponding to blue, and two imaging pixels 104 having spectral sensitivity in a wavelength band corresponding to green. , 105. In the following description, the image pickup surface on which a plurality of image pickup pixels are arranged is parallel to the xy plane, and the direction perpendicular to the xy plane is the z direction.

FIG. 1B is a schematic diagram of the image sensor 106 viewed from above the image pickup surface. As shown in FIG. 1B, the basic pixel group 101 is two-dimensionally arranged on the image pickup surface. Here, the image pickup pixels 102 to 105 that form the basic pixel group 101 have the same basic configuration except for a color filter that transmits light of a color having a specific wavelength region. Therefore, hereinafter, when describing the configuration of the image pickup pixel, the image pickup pixel 102 will be representatively described.

FIG. 2 is a schematic diagram showing a cross section parallel to the zx plane in the image pickup pixel 102 in FIG. 1A in the present embodiment. On the n-type silicon substrate 201, a photoelectric conversion unit 202 formed by ion implantation is provided from the surface side. The photoelectric conversion unit 202 is electrically separated into the sub photoelectric conversion units 202a and 202b by the central separation region 211, and the pixel region corresponding to each is a sub pixel. Ion implantation is performed from the −z direction in FIG. 2, and after thinning the back surface (+z side in FIG. 2) of the silicon substrate 201, an optical structure such as a microlens is arranged on the back surface side.

Further, the silicon substrate 201 has an insulating portion 204 made of silicon oxide (SiO _x ) formed on the back side thereof, and an in-layer microlens (inner lens) 205, a color filter 207, and a top microlens 209 formed above the insulating portion 204. Has been done. Inter-pixel light blocking walls 203 and 210 are light blocking walls for blocking light between pixels, and are arranged so as to surround each pixel. The inter-pixel light blocking wall 203 has a constant wall width in the z direction, while the inter-pixel light blocking wall 210 is formed such that the wall width increases toward the top. That is, the width of the surface of the light-shielding wall between pixels on the top microlens side (uppermost surface) is larger than the width of the surface on the photoelectric conversion unit side (lowermost surface). With this configuration, leaking light and stray light that cause harmful effects can be eliminated above, so that even when the incident angle is severe, the incident light can be efficiently guided to the photoelectric conversion unit 202 by the inner lens 205.

Next, the detailed shape of the inter-pixel light shielding wall 210 will be described with reference to FIG. 3A is a schematic view showing a cross section parallel to the xy plane in AA′ of FIG. 2, and FIG. 3B is a parallel view to the xy plane in BB′ of FIG. It is a schematic diagram showing a cross section. In FIGS. 3A and 3B, a dotted line 301 indicates a boundary with an adjacent pixel, and shows a cross-sectional shape of the inter-pixel light shielding wall 210.

FIG. 3C is an enlarged schematic view of a region 302 surrounded by a circular dotted line in FIG. 3A and shows a corner portion 303 of the inter-pixel light shielding wall 210. In the corner portion of the inter-pixel light shielding wall 210 shown in FIG. 3C, the width 304 of the side portion and the corner in the pixel diagonal direction (in the present embodiment, the direction parallel to the straight line −x=y in the figure). The width 305 of the part is shown. At this time, the area of the corner portion on the uppermost surface of the inter-pixel light shielding wall 210 is larger than the area of the corner portion on the lowermost surface of the inter-pixel light shielding wall 210. With such a configuration, it is possible to block stray light in a pixel adjacent portion between pixels in a diagonal direction. That is, in the present embodiment, the width of the corner portion on the uppermost surface of the inter-pixel light shielding wall 210 in the pixel diagonal direction is larger than the width of the corner portion on the lowermost surface of the inter-pixel light shielding wall 210 in the pixel diagonal direction. Is configured.

Further, the shape of the inter-pixel light shielding wall 210 may be any shape as long as it has a feature in its corner portion, and is not limited to the example shown in FIG. For example, the cross-sectional shape as shown in FIG. In this case, the size of the width 401 of the corner portion in the diagonal direction of the pixel is twice or more the width 402 of the side portion. Further, it may have a cross-sectional shape as shown in FIG. This example is also an example of the shape of the inter-pixel light shielding wall 210 having the same characteristics, but the part forming the side is not a side having a constant width but gradually changes. In this case, the width 404 can be considered as the width of the part forming the side.

Further, in the present embodiment, the cross-sectional shape in the pixel diagonal direction at the corner portion of the inter-pixel light shielding wall is not limited to the shape shown in FIG. For example, the example shown in FIG. 4C has a shape in which the area or width of the inter-pixel light shielding wall 210 monotonically decreases from the upper portion to the lower portion, and is similar to that in FIG. 2, but is not limited to such a shape. .. For example, as shown in FIG. 4D, the shape may be such that the width or area is increased only at the upper portion of the inter-pixel light shielding wall 210, and as shown in FIG. The shape may be such that the width or area decreases in a non-linear manner. In particular, in the case of the shape shown in FIG. 4C or FIG. 4E, since there is no step in the cross-sectional shape in the vertical direction, the manufacturing process is simplified, manufacturing accuracy is improved, and cost is reduced. You can

Further, in the present embodiment, the width or area in the pixel diagonal direction of the corner on the uppermost surface of the inter-pixel light shielding wall 210 may be larger than the width or area of the gap of the top microlens 209. Good. Even with such a configuration, it is possible to suppress stray light entering the pixel. Furthermore, the width or area in the pixel diagonal direction of the corner portion on the lowermost surface of the inter-pixel light blocking wall 210 may be smaller than the width or area of the gap of the top microlens 209. By doing so, it is possible to further improve the effect of suppressing stray light entering the pixel.

FIG. 5A is a perspective view schematically showing only the top microlens 209 and the inter-pixel light shielding wall 210. In many image pickup pixels, a flat or near-flat region exists in a corner portion of the top microlens in a diagonal direction of the pixel, and this region is called a gap 502 of the top microlens 501.

FIG. 5B is a schematic view seen from the +z direction including a part of the adjacent pixels. In FIG. 5B, a gap 502 exists at a corner portion of the top microlens 501 in the pixel diagonal direction, and a width 503 of the gap in the pixel diagonal direction is shown. FIG. 5C is a diagram showing the relationship between the width 503 of the gap 502 of the top microlens 501 in the pixel diagonal direction, the width 504 in the upper part of the inter-pixel light shielding wall 210, and the width 505 in the lower part. In the present embodiment, these width relationships are also characterized as area relationships. However, the size relationship of the widths 503, 504, and 505 in FIG. 5C is not limited to these.

Next, the focus detection method of the pupil division phase difference method will be described. FIG. 6 is a schematic diagram showing the correspondence relationship between the image sensor of this embodiment and pupil division.
In FIG. 6, a line 604 indicates the position (plane) of the subject, and forms a subject image at the image pickup element surface position 606 through the image pickup optical system at the position 605. Further, the position 609 represents the position on the back side of the inner lens of the imaging pixel forming the image sensor. The sub-photoelectric conversion unit 602 and the sub-photoelectric conversion unit 603, which are divided into two in the x direction for each pixel of the image sensor, receive the light fluxes passing through the pupil partial region 607 and the pupil partial region 608, respectively.

By selecting the signals of the sub photoelectric conversion unit 602 and the sub photoelectric conversion unit 603 for each pixel, a parallax image corresponding to a specific pupil partial region in the pupil partial region 607 and the pupil partial region 608 of the imaging optical system is obtained. Obtainable. Specifically, by selecting a signal corresponding to the sub photoelectric conversion unit 602 for each pixel, it is possible to obtain a parallax image having a resolution of the effective number of pixels corresponding to the pupil partial region 607 of the imaging optical system. Further, by selecting a signal corresponding to the sub photoelectric conversion unit 603, it is possible to obtain a parallax image having a resolution of the number of effective pixels corresponding to the pupil partial region 608 of the imaging optical system.

Further, by adding all the signals of the sub photoelectric conversion unit 602 and the sub photoelectric conversion unit 603 for each pixel, it is possible to generate a captured image with a resolution of the number of effective pixels. In the present embodiment, as shown in FIG. 6, the position of the top microlens of the image pickup pixel farther from the center of the image pickup element is decentered toward the center of the image pickup pixel. This is because the direction of the principal ray from the image forming optical system is more inclined in a portion far from the center of the image pickup element, and this inclination is dealt with.

Next, the relationship between the image shift amount of the parallax image and the defocus amount will be described. FIG. 7 is a diagram for explaining the outline of the relationship between the image shift amount between parallax images and the defocus amount. An image sensor (not shown) of the present embodiment is arranged at the image sensor surface position 606, and the exit pupil of the imaging optical system is divided into a pupil partial area 607 and a pupil partial area 608, as in FIG. I shall.

The defocus amount d represents the distance from the image forming position of the subject to the image pickup element surface position (image pickup surface) 606, and its size is |d|. Here, regarding the defocus amount d, the front focus state in which the image forming position of the subject is on the subject side from the image pickup surface is a negative sign (d<0), and the image forming position of the subject is on the opposite side of the image pickup face from the subject. The rear pin state is defined as a plus sign (d>0). The in-focus state in which the imaging position of the subject is on the imaging surface is d=0. In FIG. 7, the subject 701 shows an example in the focused state (d=0), and the subject 702 shows an example in the front focus state (d<0). Further, the front focus state (d<0) and the rear focus state (d>0) are combined into a defocus state (|d|>0).

In the front focus state (d<0), among the light fluxes from the subject 702, the light fluxes that have passed through the pupil partial region 607 (608) are once focused and then have a width around the center of gravity G1 (G2) of the light flux. It spreads to P1 (P2) and becomes a blurred image on the imaging surface 606. The blurred image is received by the sub photoelectric conversion unit 602 and the sub photoelectric conversion unit 603, and a parallax image is generated. Therefore, in the parallax image generated from the signals of the sub-photoelectric conversion unit 602 and the sub-photoelectric conversion unit 603, the subject 702 is recorded at the center of gravity position G1 (G2) as a blurred subject image with a width P1 (P2). The blur width P1 (P2) of the subject image generally increases in proportion as the size |d| of the defocus amount d increases. Similarly, the magnitude |p| of the image shift amount p (=G1-G2) of the subject images between the parallax images is approximately proportional to the magnitude |d| of the defocus amount d. Increase. Even in the rear focus state (d>0), the image shift direction of the subject image between the parallax images is opposite to the front focus state, but the same is true. In the focused state (d=0), the barycentric positions of the subject images between the parallax images match (p=0), and no image shift occurs.

Therefore, in two (plurality) parallax images obtained by using the signals of the sub-photoelectric conversion unit 602 and the sub-photoelectric conversion unit 603, as the size of the defocus amount of the parallax images increases, the plurality of parallax images The magnitude of the image shift amount between them increases. Performing focus detection using a focus detection signal of the pupil division phase difference detection method by calculating an image shift amount between parallax images by a correlation calculation using a signal from the photoelectric conversion unit of the image sensor of the present embodiment. You can

Further, in the example shown in FIG. 2, the back-illuminated image pickup pixel has no wiring layer for signal transmission between the photoelectric conversion unit 202 and the top microlens 209. In the front-illuminated image pickup pixel, it is difficult to eliminate stray light, which is scattered and absorbed in the wiring layer, in the wiring layer. Therefore, it is preferable to apply the present embodiment to the back-illuminated image pickup pixel, and the effect of suppressing stray light can be improved. With such a configuration, it is possible to realize an image sensor with higher focus detection accuracy of the phase difference method by pupil division.

Next, a specific configuration example of the image pickup apparatus to which the above-described image pickup element is applied will be described. FIG. 8 is a block diagram showing a functional configuration example of a digital camera which is an image pickup apparatus according to this embodiment, and has an image pickup element 106. In the present embodiment, a digital camera will be described as an example of the image pickup device, but the image pickup device having the above-described image pickup device may be a mobile phone, a surveillance camera, a mobile camera, a medical camera, or the like. In the image pickup apparatus of the present embodiment, the signal from the photoelectric conversion unit of the image pickup element 106 is used not only for focus adjustment of the pupil division phase difference method but also as an image pickup signal.

The digital camera of this embodiment is an interchangeable lens single-lens reflex camera, and has a lens unit 800 and a camera body 820. The lens unit 800 is attached to the camera body 820 via a mount M shown by a dotted line in the center of the figure.

The lens unit 800 has an optical system (first lens group 801, diaphragm 802, second lens group 803, focus lens group (hereinafter, simply referred to as “focus lens” 804)), and a drive/control system. As described above, the lens unit 800 includes the focus lens 804 and corresponds to a photographing lens that forms an optical image of a subject.

The first lens group 801 is arranged at the tip of the lens unit 800 and is movably held in the optical axis direction OA. The diaphragm 802 has a function of adjusting the amount of light at the time of shooting, and also functions as a mechanical shutter for controlling the exposure time at the time of shooting a still image. However, since the image sensor according to the present embodiment is provided with the global shutter mechanism, it is not always necessary to use the mechanical shutter using the diaphragm.

The diaphragm 802 and the second lens group 803 can be moved integrally in the optical axis direction OA, and a zoom function is realized by moving in conjunction with the first lens group 801. The focus lens 804 is also movable in the optical axis direction OA, and the subject distance (focus distance) on which the lens unit 800 focuses is changed depending on the position. By controlling the position of the focus lens 804 in the optical axis direction OA, focus adjustment for adjusting the focusing distance of the lens unit 800 is performed.

The drive/control system includes a zoom actuator 811, an aperture actuator 812, a focus actuator 813, a zoom drive circuit 814, an aperture stop drive circuit 815, and a focus drive circuit 816. Further, it has a lens MPU (MPU: microprocessor) 817 and a lens memory 818.

The zoom drive circuit 814 drives the first lens group 801 and the third lens group 803 in the optical axis direction OA using the zoom actuator 811, and controls the angle of view of the optical system of the lens unit 800. The diaphragm drive circuit 815 drives the diaphragm 802 using the diaphragm actuator 812, and controls the aperture diameter and the opening/closing operation of the diaphragm 802. The focus drive circuit 816 drives the focus lens 804 in the optical axis direction OA using the focus actuator 813 to change the focusing distance of the optical system of the lens unit 800. Further, the focus drive circuit 816 detects the current position of the focus lens 804 using the focus actuator 813.

The lens MPU 817 performs all calculations and controls related to the lens unit 800, and controls the zoom drive circuit 814, the diaphragm drive circuit 815, and the focus drive circuit 816. The lens MPU 817 is also connected to the camera MPU 825 through the mount M and communicates commands and data. For example, the lens MPU 817 detects the position of the focus lens 804 and notifies the lens position information to the request from the camera MPU 825. This lens position information includes the position of the focus lens 804 in the optical axis direction OA, the position and diameter of the exit pupil in the optical axis direction OA when the optical system is not moving, and the optical axis of the lens frame that limits the luminous flux of the exit pupil. It includes information such as position and diameter in direction OA. The lens MPU 817 also controls the zoom drive circuit 814, the aperture drive circuit 815, and the focus drive circuit 816 in response to a request from the camera MPU 825. Optical information required for automatic focus detection is stored in the lens memory 818 in advance. The camera MPU 825 controls the operation of the lens unit 800 by executing a program stored in a built-in non-volatile memory or a lens memory 818, for example.

The camera body 820 has an optical system (optical low-pass filter 821 and image sensor 106) and a drive/control system. The first lens group 801, the diaphragm 802, the second lens group 803, the focus lens 804 of the lens unit 800, and the optical low-pass filter 821 of the camera body 820 form an imaging optical system.

The optical low-pass filter 821 reduces false color and moire of a captured image. The image sensor 106 is the image sensor described in the present embodiment, and basically includes a microlens, an upper transparent electrode, a lower transparent electrode for pupil division, an organic photoelectric conversion film, an optical waveguide, a Si photoelectric conversion unit, and a peripheral circuit. Is composed of Further, as described above, the image sensor 106 has 6000 pixels arranged in the horizontal direction (horizontal direction) and 4000 pixels arranged in the vertical direction (vertical direction). The image sensor 106 of this embodiment has a pupil division function in the photoelectric conversion unit, and is capable of phase difference AF (autofocus) using image data based on a signal from the photoelectric conversion unit. The image processing circuit 824 generates data for phase difference AF and a moving image from image data obtained from the photoelectric conversion unit 202 of the image sensor 106. Further, the image processing circuit 824 generates still image, display, and recorded image data from the image data obtained from the photoelectric conversion unit 202.

The drive/control system includes an image pickup element drive circuit 823, an image processing circuit 824, a camera MPU 825, a display unit 826, an operation switch group 827, a memory 828, and an image pickup surface phase difference detection unit 829. The image pickup apparatus of this embodiment may include a communication unit (not shown) connected to the camera MPU 825. The communication unit is not limited to wired communication such as USB and LAN, and includes wireless communication such as wireless LAN. The imaging device of this embodiment can acquire a control signal from an external device outside via the communication unit, and can also distribute image data and the like based on the acquired control signal.

The image sensor drive circuit 823 controls the operation of the image sensor 106, A/D-converts the acquired moving image and still image signals, and transmits the signals to the camera MPU 825. The image processing circuit 824 performs general image processing such as γ conversion, white balance adjustment processing, color interpolation processing, and compression encoding processing on each image data acquired by the image sensor 106, which is performed by a digital camera. The image processing circuit 824 also generates a signal for phase difference AF (focus detection data).

The camera MPU 825 performs all calculations and controls relating to the camera body 820, and controls the image sensor drive circuit 823, the image processing circuit 824, the display unit 826, the operation switch group 827, the memory 828, and the image plane phase difference detection unit 829. .. The camera MPU 825 is connected to the lens MPU 817 via the mount M and communicates commands and data with the lens MPU 817. The camera MPU 825 requests the lens MPU 817 to obtain a lens position, a diaphragm, focus lens, and zoom drive request at a predetermined drive amount, an optical information acquisition request unique to the lens unit 800, and the like. The camera MPU 825 includes a ROM 825a that stores a program for controlling the camera operation, a RAM 825b that stores variables, and an EEPROM 825c that stores various parameters.

The display unit 826 is composed of an LCD (Liquid Crystal Display) or the like, and displays information about the shooting mode of the camera, a preview image before shooting, a confirmation image after shooting, an image in a focused state at the time of focus detection, and the like. The operation switch group 827 includes a power switch, a release (shooting trigger) switch, a zoom operation switch, a shooting mode selection switch, and the like. The memory 828 is a removable flash memory, and records image data of captured images.

The imaging plane phase difference detection unit 829 performs focus detection processing by the phase difference detection method using the focus detection data from the photoelectric conversion unit 202 obtained by the image processing circuit 824. Specifically, the image processing circuit 824 generates, as focus detection data, a pair of image data from the photoelectric conversion unit 202, which is formed by a light flux passing through a pair of pupil regions of the photographing optical system, and the imaging plane phase difference is obtained. The detection unit 829 detects the focus shift amount based on the shift amount of the pair of image data. As described above, the image pickup surface phase difference detection unit 829 of the present embodiment performs the phase difference AF (image pickup surface phase difference AF) based on the output of the image pickup element 106 without using a dedicated AF sensor.

As described above, by applying the image pickup device having the image pickup pixel having the above-described structure to the image pickup device such as a digital camera, it is possible to provide the image pickup device with high focus detection accuracy.

(Second embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. Only the points different from the first embodiment will be described below. Although the basic configuration of the image sensor is the same as that of FIG. 1, the configuration of the image pickup pixel is different from that of the first embodiment and will be described below.

FIG. 9 is a schematic diagram showing a cross section parallel to the zx plane in the image pickup pixel 102 in FIG. On the n-type silicon substrate 901, a photoelectric conversion unit 902 formed by ion implantation is provided from the surface side thereof. The photoelectric conversion unit 902 is electrically separated into the sub photoelectric conversion units 902a and 902b by the central separation region 911, and the pixel region corresponding to each is a sub pixel.

Further, the silicon substrate 901 has an insulating portion 904 made of silicon oxide (SiO _x ), a wiring layer made of a plurality of wirings 905 on the surface side thereof, and an optical waveguide made of silicon nitride (SiN _x ) so as to penetrate the insulating portion 904. The waveguide 903 is formed. Here, the edge portion region 910 represents the edge portion region of the optical waveguide 903 opposite to the silicon substrate 901 side (that is, the microlens 909 side). A color filter 907 is formed above the optical waveguide 903 via a passivation film 906, and a microlens 909 is arranged above the color filter 907.

Light incident from the outside of the image pickup pixel 102 is introduced into the optical waveguide 903 while being condensed by the microlens 909. Then, inside the optical waveguide 903, the light propagates in a state of being confined by the total reflection (sometimes partially reflected) on the side surface and reaches the photoelectric conversion unit 902. At this time, since light is confined in the optical waveguide 903, it is possible to avoid light leakage to the insulating portion 904 and light loss due to scattering and absorption in the wiring 905.

Normally, in the image pickup device, the microlenses on each pixel are shifted to the center as the distance from the center of the image pickup surface increases concentrically. For example, a microlens at a position on the image plane of about +10 millimeters from the center of the screen in the x direction is shifted by a specific amount in the x direction. FIG. 10 shows an example of an image pickup pixel in which the microlens 1001 is shifted, which is located far from the center of the image pickup surface.

However, in the pixel at the image plane position distant from the center position in this way, a light ray as indicated by an arrow 1002 in FIG. 10 collides with the edge portion region 910 of the optical waveguide 903, and the light is transmitted to the optical waveguide 903. Is not directly incident. The light that is directly incident on the optical waveguide is introduced into the photoelectric conversion unit while basically maintaining the light-collecting distribution by the microlens. On the other hand, the light that collides with the edge region 910 not only contributes to the loss itself, but also enters the inside of the optical waveguide from the outside of the side surface of the optical waveguide. This will disturb the distribution of the internal electromagnetic field. In the focus detection of the phase difference method by the pupil division in which the photoelectric conversion unit is divided, the disturbance of the electromagnetic field distribution affects the deterioration of the focus detection accuracy.

Therefore, in the present embodiment, as shown in FIG. 11, light shielding of tungsten (W) having a thickness of about 30 nm is provided on the microlens 909 side of the edge portion 910 of the optical waveguide 903 of the imaging pixel 102 of FIG. A portion 1101 is provided. Note that the material of the light blocking unit 1101 is not limited to tungsten as long as it has a property of blocking incident light by absorbing, scattering, or reflecting it. As a result, the light incident from the direction shown by the arrow 1002 in FIG. 10 is reflected and absorbed by the light shielding unit 1101, and is effectively scattered, thereby avoiding or suppressing the disturbance of the electromagnetic field distribution inside the optical waveguide 903. Is possible. That is, it is possible to suppress a decrease in focus detection accuracy of the phase difference method due to pupil division. The distance 1102 between the edge portion 910 of the optical waveguide 903 and the light shielding portion 1101 is preferably smaller than the center wavelength or the peak wavelength of the wavelength band of light handled in the pixel. As a result, it is possible to suppress light that passes through between the edge region 910 and the light shielding unit 1101 and leaks to the adjacent pixel.

FIG. 12A and FIG. 12B are diagrams showing a cross section of a pixel having an optical waveguide at a position on the image plane away from the center position, and the shading represents the distribution of the size of the pointing vector. .. This distribution shows a steady state when a plane wave having a wavelength of 550 nm is incident from a direction tilted toward the center of the image plane at an angle of 3 degrees with the z axis in the zx plane from above the microlens. 12(a) and 12(b), the gray scales of black and white representing the strength of the pointing vector are the same. The photoelectric conversion unit of the image pickup pixel in FIG. 12A is electrically divided into sub photoelectric conversion units 1204a and 1204b. Similarly, the photoelectric conversion unit of the imaging pixel in FIG. 12B is electrically divided into sub photoelectric conversion units 1205a and 1205b.

A light-shielding portion is not provided near the edge portion region of the optical waveguide in FIG. 12A, and a thickness of 30 nm made of tungsten is provided in the vicinity of the edge portion region of the optical waveguide in FIG. A light shielding portion 1203 is provided. In the example shown in FIG. 12A, the incident light is scattered in the edge portion area, and the electromagnetic field distribution inside the optical waveguide is disturbed by the light entering inside from the side surface of the optical waveguide. As a result, it can be seen that most of the light that should be mainly incident on the sub photoelectric conversion unit 1204b is incident on the sub photoelectric conversion unit 1204a on the opposite side, as shown in the region 1201.

On the other hand, in the example shown in FIG. 12B, no large disturbance of the electromagnetic field distribution is found inside the optical waveguide, and as can be seen from the region 1202, a large amount of light is incident on the sub photoelectric conversion unit 1205b which should originally enter. You can see that By adopting the configuration in which the light shielding portion is provided as shown in FIG. 12B, it is possible to suppress the deterioration of the pupil division performance and improve the focus detection accuracy. The focus detection method using the pupil division phase difference method is the same as that described in the first embodiment.

As described above, according to the present embodiment, the light shielding portion 1101 is provided at a position closer to the microlens 909 than the edge portion 910 of the optical waveguide 903, so that focus detection accuracy can be improved. If the image pickup device according to the present embodiment is applied to an image pickup device such as a digital camera, it is possible to provide an image pickup device with high focus detection accuracy. The details of the imaging device are the same as those in the first embodiment.

(Third Embodiment)
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. Only the points different from the second embodiment will be described below. Although the basic configuration of the image sensor is the same as that of FIG. 1, the configuration of the image pickup pixel is different from that of the second embodiment, and will be described below.

FIG. 13 is a schematic diagram showing a cross section parallel to the zx plane in the image pickup pixel 102 in FIG. 1A in the present embodiment. Only differences from FIG. 9 will be described below. The silicon substrate 901 has an insulating portion 1301 made of silicon oxide (SiO _x ), a wiring layer made of a plurality of wirings 905, and an optical waveguide made of silicon nitride (SiN _x ) embedded in the insulating portion 1301 on the upper surface of the silicon substrate 901. 1302 is formed. In the present embodiment, in the optical waveguide 1302, there is no edge region on the side opposite to the silicon substrate 901 side. Therefore, the insulating portion 1301 on the side of the optical waveguide 1302 is continuously arranged above the optical waveguide 1302.

As described above, in the pixel configuration of the present embodiment, the optical waveguide 1302 is embedded in the insulating portion 1301 and the edge portion region 910 as shown in FIG. 9 does not exist. Therefore, it is not necessary to consider adverse effects such as scattering and reflection at the edge portion, and it is possible to avoid deterioration of focus detection accuracy.

(Fourth Embodiment)
Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 15 is a diagram for explaining the outline of the arrangement of the image pickup pixels and the focus detection pixels of the image pickup device in the present embodiment. In FIG. 15, the pixel (imaging pixel) array of the two-dimensional CMOS sensor (imaging element) is shown in a range of 4 columns×4 rows, and the array of focus detection pixels is shown in a range of 8 columns×4 rows.

A pixel group 1500 of 2 columns×2 rows is shown at the upper left position in FIG. In the pixel group 1500, an imaging pixel 1500R having a spectral sensitivity of R (red) is in the upper left, and an imaging pixel 1500G having a spectral sensitivity of G (green) is in the upper right and lower left, and an image having a spectral sensitivity of B (blue). The pixel 1500B is arranged at the lower right. Further, each pixel is composed of a first focus detection pixel (sub-pixel) 1501 and a second focus detection pixel (sub-pixel) 1502 arranged in 2 columns×1 row.

Although a large number of pixel groups 1500 are arranged on the image pickup surface of the image pickup element, in order to simplify the description, in FIG. 15, 4 columns×4 rows of imaging pixels (8 columns×4 rows of focus points are shown). It is assumed that the detection pixels) are arranged. With such a large number of arrays, it is possible to acquire a captured image and a focus detection signal. In the present embodiment, the pixel period P is 1.0 μm, the number of pixels N is 5575 horizontal rows×3725 vertical lines=about 20.75 million pixels, the column direction period P _AF of focus detection pixels is 0.5 μm, and the focus detection pixel number N is N. _The description will be made assuming that the _AF is an image sensor having 11150 horizontal rows×3725 vertical rows=about 41530,000 pixels.

FIG. 16A shows a plan view of one image pickup pixel 1500G of the image pickup device shown in FIG. 15 as seen from the light receiving surface side (+z side) of the image pickup device, and shows a cross section taken along the line aa of FIG. 16A. A cross-sectional view seen from the −y side is shown in FIG. In the example shown in FIG. 16, the imaging pixel 1500G having the G (green) spectral sensitivity is taken as an example, but the imaging pixel 1500R having the R (red) spectral sensitivity and the B (blue) spectral sensitivity. The imaging pixel 1500B has the same configuration.

As shown in FIG. 16B, the imaging pixel according to this embodiment includes a photoelectric conversion unit 1601 including sub photoelectric conversion units 1601a and 1601b near the surface of the silicon substrate. Further, the image pickup pixel according to the present embodiment includes a top microlens 1605 for collecting the light incident from the image forming optical system and introducing the light into the image pickup pixel. Between the top microlens 1605 and the photoelectric conversion unit 1601, an insulating unit 1600 made of silicon oxide (SiO _x ), a wiring layer made of a plurality of wirings 1613, and a light guide for efficiently guiding light to the photoelectric conversion unit 1601. A waveguide 1610 is provided. The inner lens 1606 may be provided depending on the pixel design. With this pixel structure, the light incident on the imaging pixel is condensed by the top microlens 1605, dispersed by a color filter (not shown), and propagated through the optical waveguide 1610.

In addition, FIGS. 16C to 16E are diagrams for explaining how the light incident on the pixel propagates in the pixel. 16C to 16E show the results of calculation of the propagation state of a plane wave incident at a specific angle by the FDTD method (Finite Difference Time Domain Method). Here, the focal position 1607 of the top microlens 1605 is also shown. The range from the focal position 1607 to the position 1608a and the range from the focal position 1607 to the position 1608b indicate the range of the one-side focal depth of the top microlens 1605, respectively.

As shown in FIG. 16D, when light is incident at 0° with respect to the optical axis (parallel to the z direction), the two sub photoelectric conversion units 1601a and 1601b receive almost the same amount of light received. Become. On the other hand, as shown in FIG. 16C, when the light enters at −15° with respect to the optical axis, the amount of light received by the sub photoelectric conversion unit 1601b becomes larger. On the other hand, as shown in FIG. 3E, when the light enters at 15° with respect to the optical axis, the amount of light received by the sub photoelectric conversion unit 1601a becomes larger. In the sub photoelectric conversion units 1601a and 1601b, a pair of electrons and holes is generated according to the amount of light received, and after being separated in the depletion layer, negatively charged electrons are accumulated in an n-type layer (not shown). On the other hand, the holes are discharged to the outside of the image sensor through the p-type layer connected to the constant voltage source (not shown).

FIG. 17 is a diagram for explaining the outline of the correspondence relationship between the pixel structure shown in FIG. 16 and pupil division. The lower part of FIG. 17 shows a cross section of the pixel structure shown in FIG. 16A as seen from the +y side, and the upper part of FIG. 17 shows the exit pupil plane of the imaging optical system. Note that in FIG. 17, the x-axis and the y-axis of the cross-sectional view are inverted with respect to FIG. 16 in order to correspond to the coordinate axes of the exit pupil plane.

In FIG. 17, the first pupil partial region 1701 is substantially in a conjugate relationship with the light receiving surface of the sub photoelectric conversion unit 1601a whose center of gravity is decentered in the −X direction by the top microlens 1605, and the first focus detection pixel 1501. Represents a pupil region in which light can be received. The center of gravity of the first pupil partial region 1701 is eccentric to the +X side on the pupil plane.

On the other hand, in the second pupil partial region 1702, the light receiving surface of the photoelectric conversion unit 1601b whose center of gravity is decentered in the +X direction and the top microlens 1605 have a substantially conjugate relationship, and the second focus detection pixel 1502 can receive light. It represents the pupil area. The center of gravity of the second pupil partial region 1702 is eccentric to the −X side on the pupil plane. In addition, in FIG. 17, a pupil region 1700 is a pupil region in which the entire image pickup pixel 1500G can receive light when the two sub photoelectric conversion units 1601a and 1601b are all combined. The focus detection method using the phase difference method by pupil division is the same as the method described in the first embodiment.

The light fluxes that have passed through different pupil partial areas, that is, the first pupil partial area 1701 and the second pupil partial area 1702, are incident on the pixels of the image pickup pixel at different angles, respectively, and the first focus detection pixel 1501 is divided into two. The second focus detection pixel 1502 receives the light. In the imaging pixel of the present embodiment, the first focus detection pixel 1501 receives the light flux that passes through the first pupil partial area 1701 of the imaging optical system, and the second focus detection pixel 1502 passes through the second pupil partial area 1702. Receives light flux. That is, in the image sensor according to the present embodiment, a plurality of imaging pixels that receive the light flux that passes through the pupil area 1700 that is a combination of all of the first pupil partial area 1701 and the second pupil partial area 1702 are arranged.

It should be noted that the imaging pixel, the first focus detection pixel, and the second focus detection pixel each have an individual pixel configuration as necessary, and the first focus detection pixel and the second focus detection pixel are included in a part of the imaging pixel array. May be partially arranged. In the present embodiment, the first focus detection pixel 1501 of each image pickup pixel of the image pickup device is generated as a first focus signal, and the second focus detection pixel 1502 of each image pickup pixel of the image pickup device is generated as a second focus signal. Detect. Further, by adding the first focus detection pixel 1501 and the second focus detection pixel 1502 at each pixel of the image pickup pixels, an image pickup signal (taken image) having a resolution of the number of effective pixels is generated.

Next, the refractive index of each pixel of RGB will be described. FIG. 18 is a diagram for explaining the top microlens 1605 arranged in the imaging pixel and the beam waist radius of the light condensed by the top microlens 1605. In FIG. 18, a light beam 1801 is a light beam guided from the top microlens 1605. Here, the aperture angle of the top microlens 1605 is α, the focal length of the top microlens 1605 is f, the diameter of the top microlens 1605 is D, and the effective refractive index between the top microlens 1605 and the photoelectric conversion unit 1601 is n. ', the wavelength of light is λ. In this case, the beam waist radius (minimum spot radius of light) w when the light of wavelength λ is condensed by the top microlens 1605 is expressed by the following formula (1) using the formula of Rayleigh resolution (diffraction limit). Is defined by
w=1.22×fλ/n′D (1)

In an actual pixel structure, a number of layers are stacked, so that the refractive index between the top microlens and the photoelectric conversion unit is not fixed. However, in the imaging pixel having a large proportion of the optical waveguide as in the present embodiment, when the refractive index between the top microlens and the photoelectric conversion unit is considered as the effective refractive index n′, the influence of the refractive index n of the optical waveguide is affected. Is big. Therefore, the effective refractive index n'in the formula (1) greatly depends on the refractive index n in the optical waveguide. Therefore, it can be understood from the formula (1) that, in principle, the minimum spot radius w of the light condensed by the top microlens 1605 is proportional to the wavelength λ and inversely proportional to the refractive index n.

In the image sensor of the present embodiment, the size of the image pickup pixel is 1.0 μm, and the size of the subpixel when the pupil is divided is simply 0.5 μm. Since the image sensor of the pixel group as shown in FIG. 15 is composed of pixels that receive light corresponding to the wavelength bands of R (red), G (green), and B (blue), pixels corresponding to each color The wavelength of the light propagating inside is different. That is, the wavelength becomes shorter in the order of red, green, and blue.

When the refractive index inside the optical waveguide is the same, the shorter the wavelength λ is, the smaller the minimum spot radius w of the light is, and the longer the wavelength λ is, the larger the minimum spot radius w of the light is. For example, when the refractive index n inside the optical waveguide is the refractive index of SiO ₂ (about 1.46), it is difficult to introduce light into the divided sub photoelectric conversion units in the red image pickup pixel. The optical waveguide may be divided so as to correspond to the two sub photoelectric conversion units, but in this case as well, it is difficult to introduce light into the divided optical waveguide, and the longer the wavelength of light, the less the light is received. ..

In order to solve this situation, the image pickup pixel in the image pickup device of this embodiment is configured such that the R pixel has the highest refractive index inside the optical waveguide. When the refractive indices inside the optical waveguides of the R, G, and B pixels are nR, nG, and nB, respectively, the relationship of nR>nG>nB is established. As a result, even light having a long wavelength can be introduced into the narrow sub-photoelectric conversion portion or the optical waveguide.

Further, as one method of avoiding the deterioration of the pupil division performance of the R pixel, a method of sufficiently increasing the refractive index n of the optical waveguide of the entire image sensor can be considered. However, in this method, as the number of pixels becomes smaller, the separation performance between pixels is reduced, and the problem that crosstalk between pixels increases occurs. Therefore, by configuring the refractive index inside the optical waveguide to satisfy the relationship of nR>nG>nB, it is possible to reduce optical crosstalk between pixels.

FIG. 19 is a diagram for explaining a direction in which crosstalk occurs among R pixels, G pixels, and B pixels. FIG. 19A shows a case where the R pixels, the G pixels, and the B pixels all have the same refractive index n in the optical waveguide. Further, FIG. 19B shows a relationship in which the magnitude of the refractive index is nR>nG>nB when the refractive index of the R pixel is nR, the refractive index of the G pixel is nG, and the refractive index of the R pixel is nR. Is shown.

When the magnitude of the refractive index of the optical waveguide is changed in accordance with the lengths of the R, G, and B wavelengths, it becomes more difficult to guide unnecessary light beams that are sources of crosstalk between pixels to the optical waveguide. Become. A specific description will be given using the R pixel and the G pixel in FIG.

When the refractive indices of the optical waveguides are the same, the minimum spot radius of the light beam incident on the R pixel is larger than the minimum spot radius of the light beam incident on the G pixel. Therefore, by appropriately setting the refractive index nR of the R pixel and the refractive index nG of the G pixel, it is possible to prevent the light flux incident on the R pixel from crosstalking to the G pixel. Thus, although the crosstalk from the G pixel to the R pixel cannot be reduced, the crosstalk from the R pixel to the G pixel can be reduced. The same is true between the G pixel and the B pixel. Further, by appropriately setting the refractive index nB of the B pixel, crosstalk from the G pixel to the B pixel can be reduced.

As described above, according to the present embodiment, it is possible to suppress the crosstalk between pixels while avoiding the deterioration of the pupil division performance of the R pixel having a long wavelength. Although the G pixel is described as one kind of pixel in the present embodiment, the G pixel horizontally adjacent to the R pixel may be distinguished as a Gr pixel, and the G pixel horizontally adjacent to the B pixel may be distinguished as a Gb pixel. Good. Considering optical leakage from adjacent pixels, the Gr pixel and the Gb pixel may have different spectral sensitivities. Therefore, the Gr pixel and the Gb pixel may have different optical waveguide refractive indexes.

In addition, if the minimum spot radius of the red image pickup pixel is reduced at the minimum, light can be introduced into the narrow sub photoelectric conversion unit or the optical waveguide. Therefore, only the refractive index of the optical waveguide of the red image pickup pixel may be made larger than that of the other colors, and the refractive index of the optical waveguide of the green and blue image pickup pixels may be the same.

Next, an example of an image pickup apparatus using the image pickup element according to the present embodiment will be described with reference to FIG. FIG. 14 is a block diagram showing a functional configuration example of a digital camera which is an image pickup apparatus according to this embodiment, and includes the above-described image pickup element. In the present embodiment, a digital camera will be described as an example of the image pickup device, but the image pickup device having the above-described image pickup device may be a mobile phone, a surveillance camera, a mobile camera, a medical camera, or the like. In the image pickup apparatus according to the present embodiment, the signal from the photoelectric conversion unit of the image pickup element is used not only for focus adjustment of the pupil division phase difference method but also as an image pickup signal.

In FIG. 14, the first lens group 1401 arranged at the tip of the imaging optical system is held so as to be able to move back and forth in the optical axis direction. The aperture/shutter 1402 adjusts the light amount at the time of shooting by adjusting the aperture diameter thereof, and also has a function as an exposure time adjusting shutter at the time of shooting a still image. Then, the aperture/shutter 1402 and the second lens group 1403 integrally move forward and backward in the optical axis direction, and in conjunction with the forward/backward movement of the first lens group 1401, perform a zooming function (zoom function).

The third lens group 1405 performs focus adjustment by moving back and forth in the optical axis direction. The optical low pass filter 1406 is an optical element for reducing false color and moire of a captured image. The image pickup element 1407 includes a two-dimensional CMOS photo sensor and peripheral circuits, and is arranged on the image forming plane of the image forming optical system. It should be noted that in the present embodiment, as described above, the image pickup device having the image pickup pixels having different refractive indexes depending on colors is used.

The zoom actuator 1411 drives a first lens group 1401 to a third lens group 1405 to move back and forth in the optical axis direction by rotating a cam cylinder (not shown), and performs a zooming operation. The aperture shutter actuator 1412 controls the aperture diameter of the aperture/shutter 1402 to adjust the amount of photographing light and controls the exposure time during still image photographing. The focus actuator 1414 drives the third lens group 1405 forward and backward in the optical axis direction to perform focus adjustment.

The illuminating device 1415 is, for example, an electronic flash for illuminating an object at the time of photographing, and a flash illuminating device using a xenon tube is suitable, but an illuminating device including an LED that continuously emits light may be used. The AF auxiliary light unit 1416 projects an image of a mask having a predetermined aperture pattern onto a field through a light projecting lens to improve focus detection capability for a dark subject or a low contrast subject.

The control unit 1421 includes a CPU that controls various controls of the image pickup apparatus main body, and further includes an arithmetic unit, a ROM, a RAM, an A/D converter, a D/A converter, a communication interface circuit, and the like. The control unit 1421 drives various circuits included in the imaging device based on a predetermined program stored in the ROM, and executes a series of operations such as AF, shooting, image processing, and recording processing.

The electronic flash control circuit 1422 controls the lighting of the lighting device 1415 in synchronization with the shooting operation. The auxiliary light drive circuit 1423 controls the lighting of the AF auxiliary light unit 1416 in synchronization with the focus detection operation. The image pickup pixel drive circuit 1424 controls the image pickup operation of the image pickup element 1407, A/D-converts the acquired image signal, and sends the image signal to the control unit 1421. The image processing circuit 1425 performs processes such as γ conversion, color interpolation, and JPEG compression of the image acquired by the image sensor 1407.

The focus drive circuit 1426 drives and controls the focus actuator 1414 based on the focus detection result, and drives the third lens group 1405 forward and backward in the optical axis direction to perform focus adjustment. A diaphragm shutter drive circuit 1428 drives and controls the diaphragm shutter actuator 1412 to control the opening of the diaphragm/shutter 1402. The zoom drive circuit 1429 drives the zoom actuator 1411 according to the zoom operation of the photographer.

The display unit 1431 is a display device such as an LCD, and displays information about the shooting mode of the camera, a preview image before shooting and a confirmation image after shooting, a focus state display image at the time of focus detection, and the like. The operation switch group 1432 includes a power switch, a release (shooting trigger) switch, a zoom operation switch, a shooting mode selection switch, and the like. The flash memory 1433 is a removable memory and records a captured image.

As described above, by applying the image pickup device of the present embodiment to the image pickup apparatus shown in FIG. 14, it is possible to efficiently introduce light into the optical waveguide and the photoelectric conversion unit even when the image pickup pixel is small. ..

202 photoelectric conversion unit 209 top micro lens 210 light shielding wall between pixels

Claims (16)

An image pickup device in which a plurality of image pickup pixels are two-dimensionally arranged,
Each of the plurality of imaging pixels,
A plurality of electrically divided photoelectric conversion units,
A micro lens,
A light shielding wall surrounding the image pickup pixel between the photoelectric conversion unit and the microlens,
An image sensor, wherein a width of a surface of the light shielding wall on the microlens side is larger than a width of a surface of the light shielding wall on the photoelectric conversion unit side. The image pickup device according to claim 1, wherein an area of a corner portion on the surface of the light blocking wall on the microlens side is larger than an area of a gap of the microlens. The image pickup device according to claim 2, wherein an area of a corner portion on the surface of the light shielding wall on the photoelectric conversion portion side is smaller than an area of a gap of the microlens. The width of the corner portion of the light-shielding wall on the microlens side in the pixel diagonal direction is larger than the width of the corner portion of the light-shielding wall on the photoelectric conversion unit side in the pixel diagonal direction. The image pickup device according to any one of claims 1 to 3. 5. The width of the corner portion of the surface of the light shielding wall on the photoelectric conversion portion side in the pixel diagonal direction is smaller than the width of the gap of the microlens in the pixel diagonal direction. The image sensor according to Item 1. The width of a corner portion of the light shielding wall in a pixel diagonal direction is twice or more the width of a side portion of the light shielding wall. Image sensor. 7. The plurality of imaging pixels has a configuration in which a wiring layer for signal transmission is not provided between the photoelectric conversion unit and the microlens, respectively. Image sensor. An image pickup device in which a plurality of image pickup pixels are two-dimensionally arranged,
Each of the plurality of imaging pixels,
A plurality of electrically divided photoelectric conversion units,
A micro lens,
An optical waveguide for introducing light incident from the microlens between the photoelectric conversion unit and the microlens,
A region of the edge portion is formed on the microlens side of the optical waveguide, and a light shielding portion for blocking light incident on the region of the edge portion is provided on the microlens side of the region of the edge portion. An image pickup device characterized in that 9. The image pickup device according to claim 8, wherein the light blocking portion has a property of blocking incident light by absorbing, scattering, or reflecting the light. The image pickup device according to claim 8 or 9, wherein a distance between the light blocking portion and the edge portion region is shorter than a center wavelength or a peak wavelength of a wavelength band of light incident on the image pickup pixel. An image pickup device in which a plurality of image pickup pixels are two-dimensionally arranged,
Each of the plurality of imaging pixels,
A plurality of electrically divided photoelectric conversion units,
A micro lens,
An insulating section is provided between the photoelectric conversion section and the microlens,
An image pickup device, wherein an optical waveguide for introducing light incident from the microlens is embedded in a part of the insulating part on the photoelectric conversion part side. An image pickup device in which a plurality of image pickup pixels are two-dimensionally arranged,
The image pickup device has a plurality of first image pickup pixels and a plurality of second image pickup pixels,
The plurality of first imaging pixels and the plurality of second imaging pixels are respectively
A plurality of electrically divided photoelectric conversion units,
With a micro lens,
Each of the first imaging pixels further includes:
A first color filter that transmits light of a color having a first wavelength region among light incident from the microlens;
A first optical waveguide for introducing the transmitted light between the first color filter and the photoelectric conversion unit,
Each of the second imaging pixels further includes:
A second color filter that transmits light of a color having a second wavelength region smaller than the first wavelength region, of the light incident from the microlens;
A second optical waveguide for introducing the transmitted light between the second color filter and the photoelectric conversion unit,
An image pickup device, wherein the refractive index of the first optical waveguide is larger than the refractive index of the second optical waveguide. An image pickup device in which a plurality of image pickup pixels are two-dimensionally arranged,
The image sensor has a plurality of R pixels, a plurality of G pixels, and a plurality of B pixels,
The plurality of R pixels, the plurality of G pixels, and the plurality of B pixels, respectively,
A plurality of electrically divided photoelectric conversion units,
A micro lens,
Of the light incident from the microlens, a color filter that transmits light of a corresponding color,
An optical waveguide for introducing the transmitted light between the color filter and the photoelectric conversion unit,
An image pickup device characterized in that a refractive index of an optical waveguide of the R pixel is larger than a refractive index of an optical waveguide of the G pixel and the B pixel. The image pickup device according to claim 13, wherein the R pixel, the G pixel, and the B pixel are arranged in the order of increasing refractive index of the optical waveguide. The image pickup device according to claim 13 or 14, wherein the G pixel further includes a Gr pixel and a Gb pixel, and the Gr pixel and the Gb pixel have different refractive indexes of the optical waveguides. An image pickup apparatus comprising the image pickup device according to any one of claims 1 to 15.