Photovoltaic conversion device, photovoltaic conversion system, mobile body

Abstract

To provide a photoelectric conversion device capable of obtaining a wide dynamic range.SOLUTION: The photoelectric conversion device has a plurality of pixels. Each of the plurality of pixels has a first photoelectric conversion unit, a second photoelectric conversion unit, and a divergent lens that diverges incident light. The divergent lens covers at least a portion of an area of the first photoelectric conversion unit in plan view from the light input side.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a photoelectric conversion device capable of obtaining a wide dynamic range.

Background Art

[0002] In recent years, there has been a demand for a photoelectric conversion device with a wide dynamic range. A device with a high dynamic range that can simultaneously image dark and bright parts, which cannot be achieved by conventional photoelectric conversion devices, can be advantageously used, for example, in in-vehicle cameras and security cameras when there is a large difference in brightness such as backlight.

[0003] Photoelectric conversion devices that achieve a high dynamic range are shown in Patent Documents 1 to 4.

[0004] In Patent Document 1, a plurality of photodiodes with different sensitivities are formed by using the difference in the area between photodiodes to achieve a high dynamic range.

[0005] In Patent Document 2, a plurality of photodiodes with different sensitivities are realized by forming light attenuation filters with different transmittances on each photodiode.

[0006] Furthermore, Patent Documents 3 and 4 obtain a wider dynamic range by combining a plurality of photodiodes with different sensitivities and toroidal microlenses or a plurality of spherical microlenses.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

[0008] An object of the present invention is to provide a photoelectric conversion device capable of obtaining a wide dynamic range. MEANS FOR SOLVING THE PROBLEM

[0009] One aspect of the present invention is a photoelectric conversion device having a plurality of pixels, each of the plurality of pixels having a first photoelectric conversion unit, a second photoelectric conversion unit, and a diverging lens that diverges incident light, wherein the diverging lens covers at least a part of the first photoelectric conversion unit in a plan view from the light incident side.

[0010] Another aspect of the present invention is a photoelectric conversion device having a plurality of pixels, each of the plurality of pixels having a first photoelectric conversion unit, a second photoelectric conversion unit, and a diverging structure that diverges incident light, wherein the diverging structure is provided on a semiconductor substrate on which the first photoelectric conversion unit and the second photoelectric conversion unit are formed, and covers at least a part of the first photoelectric conversion unit in a plan view from the light incident side.

[0011] Still another aspect of the present invention is a photoelectric conversion device having a plurality of pixels, each of the plurality of pixels having a first photoelectric conversion unit, a second photoelectric conversion unit, and a focusing structure that focuses incident light, wherein the focusing structure is provided on a semiconductor substrate on which the first photoelectric conversion unit and the second photoelectric conversion unit are formed, and covers at least a part of the second photoelectric conversion unit in a plan view from the light incident side.

[0012] Still another aspect of the present invention is a semiconductor substrate laminated on a semiconductor substrate including a wiring layer, having a plurality of pixels including a first photoelectric conversion unit and a second photoelectric conversion unit, and including a diverging lens that diverges incident light and covers at least a part of the first photoelectric conversion unit in a plan view.

[0013] Another aspect of the present invention is a semiconductor substrate having a plurality of pixels and a diverging structure for diverging incident light, wherein each of the plurality of pixels has a first photoelectric conversion unit and a second photoelectric conversion unit, and the diverging structure covers at least a part of the first photoelectric conversion unit in a plan view.

Advantages of the Invention

[0014] According to the present invention, it is possible to provide a photoelectric conversion device capable of obtaining a wide dynamic range.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

[0016] Hereinafter, embodiments of the photoelectric conversion device of the present invention will be described with reference to the drawings. Note that the present invention is not limited by these embodiments.

[0017] In each of the embodiments described below, as an example of a photoelectric conversion device to which the present invention is applicable, an imaging device will be mainly described. However, the device to which the present invention is applicable is not limited to the imaging device. For example, the present invention is applicable to a distance measuring device (a device for distance measurement using focus detection or TOF (Time Of Flight)), a photometric device (a device for measuring the amount of incident light), and the like.

[0018] (First Embodiment) The photoelectric conversion device according to the first embodiment is an imaging device including a pixel array unit, a vertical drive unit, a column processing unit, a horizontal drive unit, a system control unit, and the like.

[0019] In the pixel array unit, unit pixels each having a photoelectric conversion element that generates and accumulates charges corresponding to the amount of incident light are arranged in an array. Hereinafter, the unit pixel will be simply referred to as a pixel, and the configuration of each pixel will be described.

[0020] FIG. 1 is a schematic cross-sectional view of a pixel of the photoelectric conversion device according to the first embodiment.

[0021] In FIG. 1, pixel 11 is a pixel of a back-illuminated CMOS image sensor in which incident light is irradiated from the upper surface in FIG. 1. In the following description, the upper surface of FIG. 1 is defined as the back surface, and the lower surface as the front surface.

[0022] Pixel 11 is configured by laminating, in order from the lower side in FIG. 1, a wiring layer 51, an oxide film 52, a semiconductor substrate 53, a dielectric material layer 54, a color filter layer 55, and an on-chip lens 109.

[0023] The wiring layer 51 is configured by embedding a plurality of wirings 101 for reading out charges accumulated in the first photoelectric conversion unit 104 and the second photoelectric conversion unit 105 formed on the semiconductor substrate 53 in an interlayer insulating film 102.

[0024] Further, a transfer gate 103 is disposed on the wiring layer 51 with respect to the semiconductor substrate 53 via an oxide film 52. When a predetermined voltage is applied to the transfer gate 103, the charges accumulated in the first photoelectric conversion unit 104 and the second photoelectric conversion unit 105 are transferred.

[0025] The wiring layer 51 is supported by a substrate support member (not shown) disposed below it. For example, by forming a charge readout circuit in the wiring layer 51 and configuring a signal processing unit after an AD conversion circuit that processes a signal based on the read charge on the substrate support member side, the image sensor can be driven at high speed.

[0026] The oxide film 52 has insulating properties and insulates the surface side of the semiconductor substrate 53.

[0027] The semiconductor substrate 53 includes a first photoelectric conversion unit 104, a second photoelectric conversion unit 105, and an inner lens 108 having a concave lens function (hereinafter also referred to as a "diverging lens 108"). The areas of the light incident surfaces of the first photoelectric conversion unit 104 and the second photoelectric conversion unit 105 for receiving incident light are different from each other, and the sensitivities to the incident light are different from each other. The first photoelectric conversion unit 104 with low sensitivity due to a smaller area of the light incident surface compared to the photoelectric conversion unit 105 is arranged so as to surround the second photoelectric conversion unit 105 with high sensitivity due to a larger area of the light incident surface compared to the photoelectric conversion unit 104.

[0028] The photoelectric conversion units 104 and 105 that convert incident light into charges are elements having a PN junction type photodiode structure or an SPAD (Single Photon Avalanche Diode) structure, but are not limited to these elements.

[0029] The diverging lens 108 has a structure in which a concave portion having a concave spherical surface is formed by digging a part of the semiconductor substrate 53, and a dielectric material layer 54 is embedded in the concave portion. The dielectric material layer is generally formed of an organic material.

[0030] For example, when Si with a refractive index of approximately 3.4 is used as the semiconductor substrate 53 and the refractive index of the dielectric material layer 54 to be embedded is approximately 1.5, a diverging lens with a large divergence angle can be formed due to the refractive index difference between the semiconductor substrate 53 and the dielectric material layer 54. In the diverging lens 108 (concave portion), a layer such as SiO 2 or SiN may be embedded, and the diverging lens 108 may have a Fresnel lens structure instead of a normal spherical lens structure. By making the diverging lens 108 have a Fresnel lens structure, the thickness of the lens can be reduced.

[0031] When the substrate 53 is viewed in a plan view from the light incident side, the diverging lens 108 is arranged to cover at least the first photoelectric conversion unit 104 among the first photoelectric conversion unit 104 and the second photoelectric conversion unit 105. By covering the first photoelectric conversion unit 104 with the diverging lens 108, the light incident on the device toward the first photoelectric conversion unit 104 is diverged by the diverging lens 108, and a part of the light is directed and incident on a portion other than the photoelectric conversion unit 104 (for example, the second photoelectric conversion unit 105). Therefore, the light incident on the first photoelectric conversion unit 104 can be made less than the case without passing through the diverging lens 108. As a result, the sensitivity difference between the first photoelectric conversion unit 104 and the second photoelectric conversion unit 105 can be increased, and the dynamic range is further widened.

[0032] Note that the pixel array portion where unit pixels are arranged has OB (Optical Black) pixels and reference pixels in addition to the unit pixels.

[0033] The OB pixel has the same element structure as the unit pixel, but a light-shielding portion (not shown) that restricts the incidence of light is provided on the light incident surface side of the pixel. Therefore, photoelectric conversion of the incident light does not occur in the photoelectric conversion unit of the OB pixel, and as the output of the OB pixel, a reference value of the black level including the dark current and noise of the photoelectric conversion unit can be obtained.

[0034] The reference pixel differs from the unit pixel and the OB pixel in that a photoelectric conversion section is not formed. Since the photoelectric conversion section is not formed, the signal output from the reference pixel is not affected by the dark current or noise of the photoelectric conversion section. As the output of the reference pixel, a reference value of the noise of the pixel section that does not include the dark current or noise of the photoelectric conversion section can be obtained.

[0035] FIG. 2 is a schematic plan view of the first and second photoelectric conversion sections of the pixel according to the first embodiment as viewed from the back side of the semiconductor substrate 53.

[0036] FIGS. 3(a) and 3(b) are schematic plan views of the first and second photoelectric conversion sections of the pixel according to the first embodiment and the diverging lens 108 as viewed from the back side of the substrate 53.

[0037] As shown in FIGS. 3(a) and 3(b), the shape of the diverging lens in plan view is not limited to a circular shape, and can be a rectangular shape or other shapes. In the present embodiment, the diverging lens 108 covers the entire first photoelectric conversion section (entirely) in plan view. However, in plan view, a form in which the diverging lens 108 covers most of the central portion of the first photoelectric conversion section but does not cover the peripheral portion, or a form in which a part of the first photoelectric conversion section is covered can also be adopted.

[0038] Furthermore, a form in which the diverging lens 108 covers the entire first photoelectric conversion section and a part of the second photoelectric conversion section in plan view can also be adopted. When the diverging lens 108 adopts a form of covering a part of the second photoelectric conversion section, the diverging lens 108 does not cover most of the second photoelectric conversion section.

[0039] As described above, the first photoelectric conversion unit 104 disposed at the center of the pixel and the second photoelectric conversion unit 105 disposed at the peripheral portion of the pixel form a nested structure in which one surrounds the other. It is desirable to arrange the first photoelectric conversion unit 104 and the second photoelectric conversion unit 105 so that their respective centers of gravity coincide. In such an arrangement, when performing signal correction for dynamic range expansion using the signal based on the charge photoelectrically converted by the first photoelectric conversion unit 104 and the signal based on the charge photoelectrically converted by the second photoelectric conversion unit 105, there is no need to consider the shift of the center of gravity between the photoelectric conversion units. That is, signal correction is easy.

[0040] In this embodiment, the first photoelectric conversion unit 104 and the second photoelectric conversion unit 105 are each composed of one photoelectric conversion unit, but they may be composed of a combination of a plurality of photoelectric conversion units. At this time, the area of the light incident surface of the first photoelectric conversion unit 104 and the second photoelectric conversion unit 105 is the sum of the areas of the light incident surfaces of the plurality of photoelectric conversion units that make up each of them.

[0041] Also, in this embodiment, the sensitivity difference between the first photoelectric conversion unit 104 and the second photoelectric conversion unit 105, which have different sensitivities to light due to the difference in the area of the light incident surface, is enlarged by a diverging lens. However, for example, even for the first and second photoelectric conversion units with equal light incident surface areas and equal sensitivities to light, it is possible to provide a sensitivity difference by a diverging lens covering the photoelectric conversion units.

[0042] Furthermore, in this embodiment, the diverging lens 108 is formed in the semiconductor substrate 53. However, for example, it is also possible to form an inner lens (diverging lens) having a concave lens function in the dielectric material layer 54 formed on the light incident surface side of the semiconductor substrate 53.

[0043] Also, on the semiconductor substrate 53, a first light shielding wall 106 that shields light between the first photoelectric conversion unit 104 and the second photoelectric conversion unit 105 is formed, and a second light shielding wall 107 that shields light between adjacent pixels is further formed. Both the first light shielding wall 106 and the second light shielding wall 107 are Al 2 O 3It is formed of a material having light-shielding properties such as W.

[0044] The first light-shielding wall 106 can effectively prevent crosstalk of light from occurring between the first photoelectric conversion unit 104 and the second photoelectric conversion unit 105.

[0045] In addition, the second light-shielding wall 107 can prevent crosstalk of light from occurring between pixels. In this case, with respect to the second photoelectric conversion units 105 of two adjacent pixels, the occurrence of crosstalk of light is prevented by the two second light-shielding walls 107 therebetween.

[0046] Note that when the position where the second photoelectric conversion unit 105 is disposed is close to the second photoelectric conversion unit 105 of an adjacent pixel, one second light-shielding wall 107 may be disposed with respect to the second photoelectric conversion units 105 of two adjacent pixels.

[0047] Alternatively, a separation part may be formed by using an impurity diffusion layer and a potential barrier that restricts the movement of charges accumulated in the photoelectric conversion unit to perform separation of each photoelectric conversion unit. By forming such a separation part, the occurrence of crosstalk of charges can be prevented.

[0048] (Modification of the First Embodiment) FIG. 4 is a diagram showing a modification of the first embodiment and is a schematic cross-sectional view of a pixel of a photoelectric conversion device.

[0049] Unlike the pixel shown in FIG. 1, the pixel shown in FIG. 4 has a height of the second light-shielding wall 107 higher than the height of the first light-shielding wall 106. Thereby, light diverged by the inner lens 108 (diverging lens 108) having a concave lens function or obliquely incident light is reflected by the second light-shielding wall 107, and the occurrence of crosstalk of light between pixels can be more effectively prevented.

[0050] Note that, in accordance with the height of the second light-shielding wall 107, it is also possible to make the height of the light incident surface of the second photoelectric conversion unit 105 higher than the height of the light incident surface of the first photoelectric conversion unit 104. Thereby, the sensitivity of the second photoelectric conversion unit 105 can be increased, and the sensitivity difference between the first photoelectric conversion unit 104 and the second photoelectric conversion unit 105 can be enlarged.

[0051] As described above, according to the first embodiment and its modification, by overlapping the divergence structure that diverges the incident light on a part of the plurality of photoelectric conversion units, the light incident on a part of the pixels is dimmed, and a sensitivity difference can be provided between the plurality of photoelectric conversion units.

[0052] In the present embodiment and the embodiments described later, a photoelectric conversion device having a plurality of photoelectric conversion units with different sensitivities whose light incident surface areas are different from each other is shown. However, the present invention is also applicable to a photoelectric conversion device having a plurality of photoelectric conversion units with different sensitivities by changing the impurity concentrations of the semiconductor regions of the photoelectric conversion units from each other. Further, the present invention is also applicable to a photoelectric conversion device having a plurality of photoelectric conversion units with different sensitivities by covering the light incident surfaces of the photoelectric conversion units with dimming filters having different transmittances from each other.

[0053] (Second Embodiment) FIG. 5 is a schematic cross-sectional view of a pixel of a photoelectric conversion device according to the second embodiment. This embodiment is different from the first embodiment in the configuration of the inner lens having a concave lens function. In the following description, parts common to the description of the first embodiment are omitted, and mainly parts different from the first embodiment will be described.

[0054] In FIG. 5, the pixel 12 is a pixel of a back-illuminated CMOS image sensor, and a wiring layer 51, an oxide film 52, a semiconductor substrate 53, a dielectric material layer 54, a color filter layer 55, and an on-chip lens 109 are laminated in order from the lower side of FIG. 5.

[0055] The configurations of the wiring layer 51 and the oxide film 52 are the same as those in the first embodiment.

[0056] On the semiconductor substrate 53, a first photoelectric conversion unit 104, a second photoelectric conversion unit 105, and a flat lens 110 having the function of a concave lens are formed. The flat lens 110 of the present embodiment is a flat diverging lens, and is a lens formed by generating a non-uniform refractive index distribution based on a periodic structure in the sub-wavelength region in the substrate. The sub-wavelength region refers to a region having a dimension equal to or smaller than the wavelength of the target light (incident light in the present embodiment). In order to realize such a periodic structure, a plurality of grooves are formed in the lens. As the main groove shapes of such a lens, structures called a blazed type, a sine wave type, and a laminar type are known.

[0057] The lens 110 is formed by digging a plurality of grooves having a width smaller than the wavelength of the incident light into the semiconductor substrate 53, and a dielectric material layer 54 is embedded therein. For example, when Si having a refractive index of about 3.4 is used as the semiconductor substrate 53 and the dielectric material layer 54 having a refractive index of about 1.5 is embedded in the plurality of grooves, Si and the dielectric material having different refractive indices are alternately arranged in the semiconductor substrate 53.

[0058] By making the average refractive index of the peripheral region of the lens 110 higher than the average refractive index of the central region, a flat lens having the function of a concave lens can be formed. Specifically, the ratio of the low refractive index structure arranged in the central region is increased compared to the ratio of the low refractive index structure arranged in the peripheral region, and conversely, the ratio of the high refractive index structure arranged in the peripheral region is increased compared to the ratio of the high refractive index structure arranged in the central region, thereby creating a difference in the average refractive index. Here, the average refractive index is a value calculated by the volume ratio of the high refractive index structure and the low refractive index structure.

[0059] Note that SiO2, SiN, etc. may be used instead of the dielectric material of the organic substance.

[0060] The lens 110 is arranged to cover at least one of the first photoelectric conversion unit 104 and the second photoelectric conversion unit 105. By arranging the lens 110 to cover the first photoelectric conversion unit 104, the incident light can be diverged by the lens 110, and the amount of light incident on the first photoelectric conversion unit 104 can be reduced. As a result, the sensitivity difference between the first photoelectric conversion unit 104 and the second photoelectric conversion unit 105 can be widened, and the dynamic range is further widened.

[0061] FIG. 6 is a schematic plan view of the first and second photoelectric conversion units and the lens 110 of the pixel according to the second embodiment as viewed from the back surface direction of the substrate 53.

[0062] In FIG. 6, the first photoelectric conversion unit 104 and the second photoelectric conversion unit 105 are arranged in a nested manner such that their respective centers of gravity coincide with each other, and further, the lens 110 is also arranged such that its center of gravity (optical axis) coincides with the centers of gravity of the conversion units 104 and 105. In such an arrangement, when performing signal correction for dynamic range expansion using the signal based on the charge converted by the first photoelectric conversion unit 104 and the signal based on the charge converted by the second photoelectric conversion unit 105, it is not necessary to consider the shift of the center of gravity between the photoelectric conversion units. That is, the signal correction is easy.

[0063] In the present embodiment, similar to the first embodiment, a light shielding wall for preventing light crosstalk between adjacent pixels and a separation portion by a potential barrier for preventing signal charge crosstalk between adjacent pixels may be formed.

[0064] Also, similar to the first embodiment, the height of the light shielding wall may be varied according to the position where the light shielding wall is installed, and the height of the light incident surface of the photoelectric conversion unit may be varied according to the height of the light shielding wall.

[0065] In this way, by causing a diverging structure such as a diverging lens to overlap a part of a plurality of photoelectric conversion units in a plan view, a sensitivity difference can be provided between the plurality of photoelectric conversion units.

[0066] (Third Embodiment) FIG. 7 is a schematic cross-sectional view of a pixel of a photoelectric conversion device according to a third embodiment.

[0067] This embodiment shows a configuration in which, in addition to a concave lens disposed at the pixel center to attenuate the light incident on the first photoelectric conversion unit, a convex lens for collecting light is disposed in the second photoelectric conversion unit. In the following description, parts overlapping with the descriptions of the first and second embodiments will be omitted, and mainly the parts different from the first and second embodiments will be described.

[0068] In FIG. 7, pixel 13 is a pixel of a back-illuminated CMOS image sensor, and a wiring layer 51, an oxide film 52, a semiconductor substrate 53, a dielectric material layer 54, a color filter layer 55, and an on-chip lens 109 are stacked in this order from the lower side of FIG. 7.

[0069] The configurations of the wiring layer 51 and the oxide film 52 are the same as those in the first embodiment.

[0070] On the semiconductor substrate 53, a first photoelectric conversion unit, a second photoelectric conversion unit, an inner lens 108 (diverging lens 108) having a concave lens function, and an inner lens 111 having a convex lens function (hereinafter also referred to as "converging lens 111") are formed.

[0071] The configuration of the diverging lens 108 is the same as that in the first embodiment, and the diverging lens 108 diverges the incident light.

[0072] In this embodiment, in addition to the diverging lens 108, a converging lens 111 for converging the incident light is formed on the back side of the semiconductor substrate 53. The converging lens 111 converges the incident light onto the second photoelectric conversion unit. The converging lens 111 is formed of, for example, SiN, SiO2, etc. having a refractive index larger than that of the dielectric material layer 54.

[0073] The diverging lens 108 is arranged to cover the first photoelectric conversion unit 104, and the converging lens 111 is arranged to cover the second photoelectric conversion unit 105. With such an arrangement, the light incident on the central part of the pixel corresponding to the first photoelectric conversion unit is diverged by the diverging lens 108, and the light incident on the first photoelectric conversion unit 104 is reduced. Further, the light incident on the peripheral part of the pixel corresponding to the second photoelectric conversion unit is converged by the converging lens 111, and the light incident on the second photoelectric conversion unit 105 can be increased. As a result, a sensitivity difference can be provided between the first photoelectric conversion unit 104 and the second photoelectric conversion unit 105, and the dynamic range is widened.

[0074] Also in this embodiment, similar to the first embodiment, a light-shielding wall for preventing light crosstalk between adjacent pixels or a separation part by a potential barrier for preventing signal charge crosstalk between adjacent pixels may be formed.

[0075] Further, similar to the first embodiment, the height of the light-shielding wall may be made different according to the position where the light-shielding wall is installed, and the height of the light incident surface of the photoelectric conversion unit may be made different according to the height of the light-shielding wall.

[0076] In this way, by arranging each of the plurality of photoelectric conversion units so as to be covered by a diverging structure such as a diverging lens and a converging structure such as a converging lens, a sensitivity difference can be provided between the plurality of photoelectric conversion units.

[0077] (Fourth Embodiment) The photoelectric conversion system according to this embodiment will be described with reference to FIG. 8. FIG. 8 is a block diagram showing a schematic configuration of the photoelectric conversion system according to this embodiment.

[0078] The photoelectric conversion device (imaging device) described in the above first to third embodiments is applicable to various photoelectric conversion systems. Examples of applicable photoelectric conversion systems include digital still cameras, digital camcorders, surveillance cameras, copiers, fax machines, mobile phones, in-vehicle cameras, observation satellites, and the like. Further, a camera module including an optical system such as a lens and an imaging device is also included in the photoelectric conversion system. FIG. 8 illustrates a block diagram of a digital still camera as an example of these.

[0079] The photoelectric conversion system illustrated in FIG. 8 includes an imaging device 1004, which is an example of the photoelectric conversion device described in the above first to third embodiments, and a lens 1002 that forms an optical image of a subject on the imaging device 1004. Further, it has a diaphragm 1003 for variably controlling the amount of light passing through the lens 1002 and a barrier 1001 for protecting the lens 1002. The lens 1002 and the diaphragm 1003 are an optical system that condenses light on the imaging device 1004. The imaging device 1004 is the photoelectric conversion device (imaging device) of any of the above embodiments, and converts the optical image formed by the lens 1002 into an electrical signal.

[0080] The photoelectric conversion system also has a signal processing unit 1007, which is an image generation unit that generates an image by processing the output signal output from the imaging device 1004. The signal processing unit 1007 performs operations such as various corrections and compressions as necessary to output image data. The signal processing unit 1007 may be formed on the semiconductor substrate on which the imaging device 1004 is provided, or may be formed on a semiconductor substrate different from the imaging device 1004.

[0081] The photoelectric conversion system further includes a memory unit 1010 for temporarily storing image data, and an external interface unit (external I / F unit) 1013 for communicating with an external computer or the like. The photoelectric conversion system further includes a recording medium 1012 such as a semiconductor memory for recording or reading imaging data, and a recording medium control interface unit (recording medium control I / F unit) 1011 for recording or reading from the recording medium 1012. Note that the recording medium 1012 may be built into the photoelectric conversion system or may be detachable.

[0082] Furthermore, the photoelectric conversion system includes an overall control and arithmetic unit 1009 for performing various operations and controlling the entire digital still camera, and a timing generation unit 1008 for outputting various timing signals to the imaging device 1004 and the signal processing unit 1007. Here, the timing signals and the like may be input from the outside, and the photoelectric conversion system may have at least the imaging device 1004 and the signal processing unit 1007 that processes the output signal output from the imaging device 1004.

[0083] The imaging device 1004 outputs a signal (imaging signal) formed by photoelectrically converting an optical image to the signal processing unit 1007. The signal processing unit 1007 performs predetermined signal processing on the imaging signal output from the imaging device 1004 and outputs image data. The signal processing unit 1007 generates an image using the imaging signal.

[0084] Thus, according to this embodiment, a photoelectric conversion system applying the photoelectric conversion device (imaging device) of any of the above embodiments can be realized.

[0085] (Fifth Embodiment) The photoelectric conversion system and the moving body of this embodiment will be described with reference to FIG. 9. FIG. 9 is a diagram showing the configuration of the photoelectric conversion system and the moving body of this embodiment.

[0086] FIG. 9(a) shows an example of a photoelectric conversion system related to an in-vehicle camera. The photoelectric conversion system 300 includes an imaging device 310. The imaging device 310 is the photoelectric conversion device (imaging device) described in any of the above embodiments. The photoelectric conversion system 300 includes an image processing unit 312 that performs image processing on a plurality of pieces of image data acquired by the imaging device 310, and a parallax acquisition unit 314 that calculates a parallax (phase difference of a parallax image) from the plurality of pieces of image data acquired by the photoelectric conversion system 300. Further, the photoelectric conversion system 300 includes a distance acquisition unit 316 that calculates the distance to an object based on the calculated parallax, and a collision determination unit 318 that determines whether there is a possibility of collision based on the calculated distance. Here, the parallax acquisition unit 314 and the distance acquisition unit 316 are examples of distance information acquisition means for acquiring distance information to an object. That is, the distance information is information related to parallax, defocus amount, distance to an object, and the like. The collision determination unit 318 may determine the possibility of collision using any of these distance information. The distance information acquisition means may be realized by dedicatedly designed hardware, or may be realized by a software module. Further, it may be realized by an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or the like, or may be realized by a combination of these.

[0087] The photoelectric conversion system 300 is connected to a vehicle information acquisition device 320 and can acquire vehicle information such as vehicle speed, yaw rate, and steering angle. Further, the photoelectric conversion system 300 is connected to a control ECU 330 which is a control device that outputs a control signal for generating a braking force for the vehicle based on the determination result of the collision determination unit 318. Further, the photoelectric conversion system 300 is also connected to an alarm device 340 that issues an alarm to the driver based on the determination result of the collision determination unit 318. For example, when the determination result of the collision determination unit 318 indicates a high possibility of collision, the control ECU 330 performs vehicle control to avoid collision and reduce damage, such as applying brakes, returning the accelerator, and suppressing engine output. The alarm device 340 warns the user by sounding an alarm such as a sound, displaying alarm information on a screen of a car navigation system, or applying vibration to a seat belt or steering wheel.

[0088] In the present embodiment, the photoelectric conversion system 300 images the surroundings of the vehicle, for example, the front or the rear. Fig. 9(b) shows the photoelectric conversion system when imaging the front of the vehicle (imaging range 350). The vehicle information acquisition device 320 sends an instruction to the photoelectric conversion system 300 or the imaging device 310. With such a configuration, the ranging accuracy can be further improved.

[0089] In the above, an example of controlling to avoid collision with other vehicles has been described, but it is also applicable to controls such as automatic driving following other vehicles and automatic driving so as not to deviate from the lane. Further, the photoelectric conversion system can be applied not only to vehicles such as the host vehicle, but also to moving bodies (moving devices) such as ships, aircraft, or industrial robots. In addition, it can be applied not only to moving bodies, but also to devices that widely utilize object recognition, such as an advanced road traffic system (ITS).

[0090] [Modified Embodiment] The present invention is not limited to the above embodiment and various modifications are possible.

[0091] For example, embodiments of the present invention also include examples in which a part of the configuration of one embodiment is added to another embodiment, or examples in which a part of the configuration of another embodiment is replaced.

[0092] In addition, the photoelectric conversion systems of the fourth embodiment shown in FIG. 8 and the fifth embodiment shown in FIG. 9 are examples of photoelectric conversion systems to which the photoelectric conversion device can be applied. The photoelectric conversion system applicable to the photoelectric conversion device of the present invention is not limited to the configurations shown in FIGS. 8 and 9.

[0093] It should be noted that the above embodiments are merely specific examples for implementing the present invention, and the technical scope of the present invention should not be construed in a limited manner by these. That is, the present invention can be implemented in various forms without departing from its technical idea or its main features.

Description of Reference Numerals

[0094] 53 Semiconductor substrate 104 First photoelectric conversion unit 105 Second photoelectric conversion unit 108 Concave lens type inner lens

Claims

1. A photoelectric conversion device having a plurality of pixels, each of the plurality of pixels having a first photoelectric conversion section, a second photoelectric conversion section, and a diverging lens that diverges incident light, wherein the diverging lens is provided on a semiconductor substrate on which the first photoelectric conversion section and the second photoelectric conversion section are formed, and covers at least a part of the first photoelectric conversion section in a plan view from the light incident side, wherein the sensitivity of the first photoelectric conversion section to incident light is lower than the sensitivity of the second photoelectric conversion section to incident light, and a part of the light diverged by the diverging lens is incident on the second photoelectric conversion section. A photoelectric conversion device characterized by this.

2. The photoelectric conversion device according to claim 1, wherein the area of the light incident surface of the first photoelectric conversion section is smaller than the area of the light incident surface of the second photoelectric conversion section.

3. The photoelectric conversion device according to claim 1 or 2, wherein the second photoelectric conversion section is arranged so as to surround the first photoelectric conversion section.

4. The photoelectric conversion device according to any one of claims 1 to 3, wherein the diverging lens is a lens formed by covering a concave portion of the semiconductor substrate with a material having a refractive index lower than that of the semiconductor substrate.

5. The photoelectric conversion device according to any one of claims 1 to 4, wherein the diverging lens is a Fresnel lens that functions as a concave lens.

6. The photoelectric conversion device according to any one of claims 1 to 5, wherein the diverging lens is a lens that diverges incident light by a periodic structure in a sub-wavelength region.

7. Between the first photoelectric conversion section and the second photoelectric conversion section, The photoelectric conversion device according to any one of claims 1 to 6, further comprising a first light shielding wall that shields light.

8. Between the pixels, The photoelectric conversion device according to any one of claims 1 to 7, further comprising a second light shielding wall that shields light.

9. Between the first photoelectric conversion section and the second photoelectric conversion section, a first light shielding wall that shields light is provided, The photoelectric conversion device according to claim 8, wherein the height of the second light shielding wall is higher than the height of the first light shielding wall.

10. Between the first photoelectric conversion section and the second photoelectric conversion section, The photoelectric conversion device according to any one of claims 1 to 9, further comprising a separation section that restricts the movement of charges.

11. Between the pixels, The photoelectric conversion device according to any one of claims 1 to 10, characterized by comprising a separation part that restricts the movement of charges.

12. having a focusing lens that focuses the light incident on the pixel onto the second photoelectric conversion part, The photoelectric conversion device according to any one of claims 1 to 11, characterized in that the focusing lens covers at least a part of the second photoelectric conversion part in a plan view from the light incident side.

13. A photoelectric conversion device according to any one of claims 1 to 12, and a signal processing part that generates an image using the signal output by the photoelectric conversion device. A photoelectric conversion system characterized by having the above.

14. A moving body comprising the photoelectric conversion device according to any one of claims 1 to 12, characterized by having a control part that controls the movement of the moving body using the signal output by the photoelectric conversion device.

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