Image sensor, camera module and electronic device

Abstract

The application discloses an image sensor, a camera module and an electronic device. The image sensor comprises a substrate, an optical control component and a plurality of light sensing units. The optical control component has a plurality of light collection partitions. The plurality of light collection elements in the light collection partitions can converge incident light in the corresponding area. Since the light received by the light sensing units of different types is different in color, the structure of the plurality of light collection elements in different light collection partitions can be matched with the characteristic light received by the light sensing units of the corresponding type, so that the focusing depth of the light of different colors focused by the optical control component is the same, thereby reducing the difference between the focusing positions of the characteristic light received by the light sensing units of different types, and further reducing the difference in intensity distribution of the incident light entering the light sensing units of different types, so as to improve the imaging quality.

Description

Technical Field

[0001] This application relates to the field of image sensing technology, and in particular to an image sensor, a camera module, and an electronic device. Background Technology

[0002] An image sensor is a device that converts received light signals into electrical signals.

[0003] Image sensors are widely used in the optical imaging of electronic devices such as digital cameras, smartphones, virtual reality, and augmented reality. Some current image sensors employ phase detection autofocus, but these suffer from poor image quality due to chromatic aberration. Utility Model Content

[0004] This application provides an image sensor, a camera module, and an electronic device. The technical solution is as follows: According to a first aspect of this application, an image sensor is provided, the image sensor comprising: a substrate, an optical control component, and a plurality of photosensitive units; The plurality of photosensitive units are located on the same side of the substrate, and the plurality of photosensitive units include at least two types of photosensitive units, and the different types of photosensitive units are used to receive light of different colors; The optical control component is located on the side of the plurality of photosensitive units away from the substrate, and the metasurface lens has a plurality of light-concentrating zones arranged in an array, with a plurality of light-concentrating elements distributed in each light-concentrating zone; The plurality of light-concentrating zones correspond to the plurality of photosensitive units, and the orthographic projection of the light-concentrating zone on the substrate overlaps with the orthographic projection of the corresponding photosensitive unit on the substrate; different colors of light are focused to the same depth after being focused by the optical control component.

[0005] Here, multiple focusing elements in the focusing zone can converge the incident light in the corresponding area. Since different types of photosensitive units receive different colors of light, the structure of multiple focusing elements in different focusing zones can be matched with the characteristic light received by the corresponding type of photosensitive unit, so that the focusing depth of different colors of light after being focused by the optical control component is the same. This can reduce the difference in the focusing position of the characteristic light received by different types of photosensitive units, and further reduce the difference in intensity distribution of incident light entering different types of photosensitive units, thereby improving the image quality.

[0006] In some possible implementations, the optical control component is a metasurface lens, the light-concentrating element is a nanopillar, and multiple nanopillars within each light-concentrating zone are arranged in an array.

[0007] In some possible implementations, the plurality of photosensitive units include: a plurality of first photosensitive units and a plurality of second photosensitive units of different types, wherein the first photosensitive units are used to receive a first color light and the second photosensitive units are used to receive a second color light; the light-gathering zone corresponding to the first photosensitive unit is a first light-gathering zone and the light-gathering zone corresponding to the second photosensitive unit is a second light-gathering zone; Each nanopillar within the first focusing zone corresponds one-to-one with a nanopillar within the second focusing zone. For the first nanopillar within the first focusing zone and the second nanopillar within the second focusing zone, the distribution position of the first nanopillar within the first focusing zone is the same as the distribution position of the second nanopillar within the second focusing zone. The first nanopillar is any one of the nanopillars distributed within the first focusing zone, and the second nanopillar is the nanopillar within the second focusing zone that corresponds to the first nanopillar. The distribution pattern of the multiple nanopillars in the first focusing zone is different from that in the second focusing zone.

[0008] In this case, by adjusting the distribution pattern of multiple nanopillars in different focusing zones, it is easy to adjust the focal length of multiple nanopillars in the first focusing zone for the first color light, and the focal length of multiple nanopillars in the second focusing zone for the second color light, so that the focal lengths of the two are the same, thereby eliminating the color difference problem.

[0009] In some possible implementations, the size of the orthographic projection of the first nanopillar onto the substrate is the same as the size of the orthographic projection of the second nanopillar onto the substrate; the height of the first nanopillar is different from the height of the second nanopillar.

[0010] Here, by adjusting the height of the nanopillars, the distribution pattern of multiple nanopillars in the first focusing zone is different from that in the second focusing zone.

[0011] In some possible implementations, the wavelength of the first color light is greater than the wavelength of the second color light, and the height of the first nanopillar is greater than the height of the second nanopillar.

[0012] In this case, the focusing effect of the first focusing zone can be improved, thereby reducing the focusing depth of the first color light, and thus making the focusing depth of the first color light and the second color light the same, so as to improve the image quality.

[0013] In some possible implementations, the height of the first nanopillar is the same as the height of the second nanopillar; the size of the orthographic projection of the first nanopillar onto the substrate is different from the size of the orthographic projection of the second nanopillar onto the substrate.

[0014] Here, by adjusting the size of the orthographic projection on the nanopillar substrate, the distribution pattern of multiple nanopillars in the first focusing zone is different from that in the second focusing zone.

[0015] In some possible implementations, the nanopillars are cylindrical, and the diameter of the nanopillars ranges from 50 nanometers to 200 nanometers; and / or, the height of the nanopillars ranges from 200 nanometers to 1000 nanometers.

[0016] In some possible implementations, the nanopillars are cylindrical structures made of any one of silicon, gallium nitride, titanium oxide, and silicon nitride.

[0017] In some possible implementations, the image sensor further includes: a plurality of filter units corresponding to the plurality of photosensitive units, wherein the filter units are located on the side of the corresponding photosensitive unit closer to the optical control component, and the orthographic projection of the filter unit on the substrate overlaps with the orthographic projection of the corresponding photosensitive unit on the substrate; The filter unit corresponding to the first photosensitive unit is a first filter unit, and the filter unit corresponding to the second photosensitive unit is a second filter unit; the first filter unit is used to transmit the first color light, and the second filter unit is used to transmit the second color light.

[0018] Here, the filter unit is used to allow light of a specific wavelength to pass through and block light of other wavelengths. The specific wavelength matches the spectral response characteristics of the corresponding photosensitive unit, so the corresponding photosensitive unit can respond to the light of that wavelength to achieve photoelectric conversion, thereby ensuring color accuracy.

[0019] In some possible implementations, within the same focusing zone, at least some of the focusing elements have different sizes of their orthogonal projections onto the substrate.

[0020] Secondly, a camera module is provided, the camera module comprising: a lens assembly and an image sensor, wherein the image sensor is the image sensor described above.

[0021] Thirdly, an electronic device is provided, the electronic device comprising: the aforementioned camera module. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of an image sensor provided by related technologies; Figure 2 yes Figure 1 A schematic diagram of the sensitivity of the provided image sensor; Figure 3 This is a partial top view of an image sensor provided in an embodiment of this application; Figure 4 yes Figure 3 A schematic cross-sectional view of the provided image sensor at point A1-A1; Figure 5 yes Figure 3 Another schematic cross-sectional view of the provided image sensor at A1-A1; Figure 6 This is a schematic diagram of the phase distribution of a metasurface lens provided in an embodiment of this application; Figure 7 This is a schematic diagram of another image sensor structure provided in an embodiment of this application; Figure 8 This is a three-dimensional structural schematic diagram of a metasurface lens provided in an embodiment of this application; Figure 9 This is a partial top view of a portion of the structure of another image sensor provided in this application; Figure 10 yes Figure 9 A schematic cross-sectional view of the provided image sensor at point A2-A2; Figure 11 yes Figure 10 A schematic diagram of the sensitivity of the provided image sensor; Figure 12 This is a schematic diagram illustrating the autofocus performance of an image sensor provided by related technologies; Figure 13 This is a schematic diagram illustrating the autofocus performance of an image sensor according to an embodiment of this application; Figure 14 This is a schematic diagram of the incident light of an image sensor provided in an embodiment of this application; Figure 15 This is a schematic diagram of another image sensor structure provided by related technologies.

[0024] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0026] Please refer to Figure 1 , Figure 1 This is a schematic diagram of an image sensor structure provided by related technology. The image sensor 300 includes: a substrate 310, an isolation structure 320, photosensitive units 330, a filter unit 340, and microlenses 350. The multiple photosensitive units 330 include: a green photosensitive unit 330a, a red photosensitive unit 330b, and a blue photosensitive unit 330c, and these three types of photosensitive units 330 receive light of different wavelengths. The multiple microlenses 340 in the image sensor 300 all have the same radius of curvature, but the refractive index of light of different wavelengths is different in the microlenses 340. Therefore, the focusing depth of the microlenses 340 for light of different wavelengths varies significantly, such as... Figure 1 As shown, the focusing depth of red light corresponding to the red photosensitive unit 330b is greater than the focusing depth of green light corresponding to the green photosensitive unit 330a, which is greater than the focusing depth of blue light corresponding to the blue photosensitive unit 330c. The difference in focusing depth will cause color difference problems, which will easily lead to poor image quality.

[0027] In related technologies, the photosensitive unit 330 includes at least two photodiodes 331 to achieve phase detection autofocus. Please refer to... Figure 2 , Figure 2 yes Figure 1 The provided image sensor sensitivity diagram illustrates that, since the isolation structure 320 is designed based on the green photosensitive unit 330a, the light distribution of the isolation structure 320 is only adapted to the green photosensitive unit 330a. This ensures that the multiple photodiodes 331 within the green photosensitive unit 330a have no sensitivity difference, where sensitivity reflects the intensity of light received by the photodiodes 331. However, for the red photosensitive unit 330b and the blue photosensitive unit 330c, due to the difference in focus depth, the sensitivity difference of the photodiodes 331 within the red photosensitive unit 330b and the blue photosensitive unit 330c still exists. This results in significant differences in autofocus performance corresponding to different types of photosensitive units 330, leading to poorer image quality.

[0028] This application provides an image sensor, please refer to... Figure 3 and Figure 4 , Figure 3 This is a partial top view of an image sensor provided in an embodiment of this application. Figure 4 yes Figure 3 A schematic cross-sectional view of the provided image sensor at A1-A1. The image sensor 100 includes: a substrate 110, an optical control assembly 120, and a plurality of photosensitive units 130.

[0029] In this application, the image sensor 100 can be a CMOS image sensor (CIS), where CMOS stands for Complementary Metal Oxide Semiconductor. CMOS image sensors have the characteristics of high integration, low power consumption, high-speed readout, and flexible process.

[0030] The substrate 110 is used to support other structures in the image sensor 100, such as the metasurface lens 120 and multiple photosensitive units 130. In some possible implementations, a circuit structure can be integrated in the substrate 110, which can be electrically connected to the photosensitive units 130. The circuit structure can then process and transmit the electrical signals converted by the photosensitive units 130 to form the final electronic image.

[0031] Multiple photosensitive units 130 are located on the same side of the substrate 110. Here, the photosensitive units 130 are used to convert optical signals into electrical signals. Each photosensitive unit 130 may include at least one photodiode 131, wherein at least one photodiode 131 in the same photosensitive unit 130 responds to light of the same wavelength. The photodiode 131 is capable of converting photons into electron-hole pairs, generating a photocurrent whose magnitude is proportional to the light intensity, thereby generating an electrical signal. For example, a photosensitive unit 12 may contain four photodiodes, arranged in a row and column.

[0032] The plurality of photosensitive units 130 include at least two types of photosensitive units 130, each type of photosensitive unit 130 being used to receive light of different colors. For example, the photosensitive unit 130 may be used to receive one of red light, green light, and blue light.

[0033] The optical control component 120 is located on the side of the plurality of photosensitive units 130 facing away from the substrate 110. The optical control component 120 has a plurality of focusing zones Q arranged in an array, and a plurality of focusing elements 121 are distributed in each focusing zone Q. Here, the optical control component 120 is a component capable of controlling the optical path of the incident beam, and the focusing element 121 is the smallest unit in the optical control component 120. By controlling the optical path of the incident beam through the plurality of focusing elements 121 in the optical control component 120, the incident beam from the outside can be focused, thereby enhancing the light collection efficiency of the image sensor 100. Furthermore, in low-light environments, the focusing effect of the optical control component 120 can also improve the sensitivity of the image sensor 100.

[0034] In this system, multiple focusing zones Q correspond to multiple photosensitive units 130, and the orthographic projection of the focusing zone Q onto the substrate 110 overlaps with the orthographic projection of the corresponding photosensitive unit 130 onto the substrate 110. That is, an external incident light beam, after being focused by multiple focusing elements 121 in the focusing zone Q, enters the corresponding photosensitive unit 130 so that the corresponding photosensitive unit 130 can perform photoelectric conversion.

[0035] Light of different colors is focused to the same depth after being focused by the optical control component 120, which can reduce the difference in the focusing position of the characteristic light received by different types of photosensitive units 130, and thus eliminate the color difference problem caused by using the same microlens in related technologies.

[0036] It should be noted that, Figure 2 and Figure 3 Only one optical control component 120 is shown as an example, but the embodiments of this application are not limited thereto. The optical control component 120 can be various components with light-gathering effects.

[0037] In summary, this application provides an image sensor in which the optical control component has multiple focusing zones. The multiple focusing elements in the focusing zones can converge the incident light in the corresponding areas. Since different types of photosensitive units receive different colors of light, the structure of the multiple focusing elements in different focusing zones can be matched with the characteristic light received by the corresponding type of photosensitive unit, so that the focusing depth of different colors of light after being focused by the optical control component is the same. This can reduce the difference in the focusing position of the characteristic light received by different types of photosensitive units, and further reduce the difference in intensity distribution of incident light entering different types of photosensitive units, thereby improving the imaging quality.

[0038] In some possible implementations, the optical control component 120 is a metasurface lens, and the focusing element 121 is a nanopillar, with multiple nanopillars 121 arranged in an array within each focusing partition Q. Here, the multiple nanopillars 121 in the metasurface lens 120 can change the phase distribution of the incident beam, thereby enabling focusing of the external incident beam.

[0039] Compared to microlenses, metasurface lenses 120 offer greater flexibility. By adjusting the structure and arrangement of multiple focusing elements 121 in each focusing zone Q, each focusing zone Q can provide more precise light adjustment, optimizing the focusing paths of different colors of light and thus eliminating the effects of chromatic aberration. Due to the high flexibility and small size of the optical control assembly 120, performance improvements can be achieved without increasing the volume of the image sensor 100, making it suitable for various portable electronic devices.

[0040] It should be noted that, Figure 2 and Figure 3 The present invention only illustrates the structure and arrangement of multiple nanopillars 121 in a metasurface lens 120, but the embodiments of this application are not limited thereto. Specifically, the arrangement can be determined based on parameters such as the wavelength of the light received by the photosensitive unit 130 corresponding to each focusing zone Q.

[0041] The structure of the metasurface lens is explained below: For some possible implementations, please refer to Figure 3 and Figure 5 , Figure 5 yes Figure 3 Another cross-sectional schematic diagram of the provided image sensor at A1-A1. The plurality of photosensitive units 130 include: a plurality of first photosensitive units 130a and a plurality of second photosensitive units 130b of different types, wherein the first photosensitive units 130a are used to receive a first color light, and the second photosensitive units 130b are used to receive a second color light. For example, the first color light may be one of red light, green light, and blue light, and the second color light may be another of red light, green light, and blue light.

[0042] The focusing zone Q corresponding to the first photosensitive unit 130a is designated as the first focusing zone Q1, and the focusing zone Q corresponding to the second photosensitive unit 130b is designated as the second focusing zone Q2. The focusing ability of the multiple focusing elements 121 within the first focusing zone Q1 for the first color light is the same as the focusing ability of the multiple focusing elements 121 within the second focusing zone Q2 for the second color light. For example, the focal length of the multiple focusing elements 121 within the first focusing zone Q1 for the first color light is the same as the focal length of the multiple focusing elements 121 within the second focusing zone Q2 for the second color light. Thus, the depth of focus of the first color light after passing through the first focusing zone Q1 is the same as the depth of focus of the second color light after passing through the second focusing zone Q2.

[0043] Therefore, the structure of multiple focusing elements 121 in different focusing zones Q can be matched with the characteristic light received by the corresponding photosensitive unit 130, so that each focusing zone Q has the same focusing ability for the characteristic light received by the corresponding photosensitive unit 130, and the focusing depth of different colors of light after being focused by the optical control component 120 is the same. This can reduce the difference in the focusing position of the characteristic light received by different types of photosensitive units 130, and thus eliminate the color difference problem caused by using the same microlens in related technologies.

[0044] Multiple nanopillars 121 are arranged in an array within each focusing zone Q, with a one-to-one correspondence between the multiple nanopillars 121 in the first focusing zone Q1 and the multiple nanopillars 121 in the second focusing zone Q2. That is, the number of nanopillars 121 in each focusing zone Q is the same, and the arrangement of the nanopillars 121 in each focusing zone Q is identical. For example, as shown... Figure 2 As shown, in the first focusing partition Q1 and the second focusing partition Q2, multiple nanopillars 121 are arranged in 5 rows and 5 columns (5 5) Arrangement, but this application is not limited to this. For example, the multiple nanopillars 121 in each focusing partition Q2 can also be arranged in 3 rows and 3 columns (3 3) Arrangement, or 6 rows and 6 columns (6 6) Arrangement.

[0045] For the first nanopillar 121a within the first focusing partition Q1 and the second nanopillar 121b within the second focusing partition Q2, the distribution position of the first nanopillar 121a within the first focusing partition Q1 is the same as the distribution position of the second nanopillar 121b within the second focusing partition Q2. The first nanopillar 121a is any one of the multiple nanopillars 121 distributed within the first focusing partition Q1, and the second nanopillar 121b is the nanopillar 121 corresponding to the first nanopillar 121a among the multiple nanopillars 121 distributed within the second focusing partition Q2. Here, the distribution position of the nanopillar 121 within the focusing partition Q can be the row or column where the nanopillar 121 is located. For example, as shown... Figure 3 As shown, the first nanopillar 121a can be the nanopillar 121 in the 3rd row and 5th column within the first focusing partition Q1, and the second nanopillar 121b corresponding to the first nanopillar 121a is the nanopillar 121 in the 3rd row and 5th column within the second focusing partition Q2.

[0046] The distribution pattern of the multiple nanopillars 121 in the first focusing zone Q1 differs from that in the second focusing zone Q2. Here, the distribution pattern of the multiple nanopillars 121 can be parameters such as the shape, size, spacing, and orientation of the nanopillars 121 at various locations within the focusing zone Q. Changes in these parameters affect the light modulation effect of each nanopillar 121, thus affecting the focusing performance of each focusing zone Q. Therefore, by adjusting the distribution patterns of the multiple nanopillars 121 in different focusing zones Q1, it is possible to easily adjust the focal length of the multiple nanopillars 121 in the first focusing zone Q1 for the first color light, and the focal length of the multiple nanopillars 121 in the second focusing zone Q2 for the second color light, so that their focal lengths are the same, thereby eliminating the color difference problem.

[0047] In some possible implementations, within the same focusing zone Q, at least some of the focusing elements 121 have different orthographic projection dimensions on the substrate 110. For example, such as... Figure 5 As shown, the diameters of the nanopillars 121 within the same focusing partition Q are different.

[0048] In some possible implementations, when incident light from the outside strikes each focusing section Q of the metasurface lens 120, the multiple nanopillars 121 in the focusing section Q can adjust the phase of the incident light so that the phase of the incident light after being adjusted by the metasurface lens 120 satisfies the following formula: ; ; Where φ is the focused phase of the incident light after being adjusted by the metasurface lens 120, and A i Let A be a coefficient. i Related to the wavelength of the incident light, ρ is the normalized radial coordinate, x and y are the position coordinates of the nanopillars 121 in the metasurface lens 120, and R is the radius of the metasurface lens 120. Based on the required phase information φ, the dimensions of the nanopillars 121 corresponding to each position coordinate can be simulated, and multiple nanopillars 121 can be arranged to form various focusing zones Q, thereby achieving the focusing function.

[0049] In some possible implementations, the phase distribution of the metasurface lens can be referenced. Figure 6 , Figure 6 This is a schematic diagram of the phase distribution of a metasurface lens provided in an embodiment of this application, where the horizontal axis represents the distance between the nanopillar and the center of the focusing partition, in micrometers, and the vertical axis represents the phase. Based on Figure 6 The required phase information for each distribution location of the nanopillars 121 can be determined, for example, such as Figure 6As shown, the nanopillars 121 that are closer to the center of the focusing partition Q require a larger phase.

[0050] In this application embodiment, in order to satisfy the different distribution patterns of the multiple nanopillars 121 in the first focusing partition Q1 and the multiple nanopillars 121 in the second focusing partition Q2, various implementation methods can be adopted. Among them, adjusting the height of the nanopillars 121 and the size of the orthographic projection of the nanopillars 121 on the substrate 110 is relatively convenient. Two exemplary embodiments are described below: In a first exemplary embodiment, please refer to Figure 3 and Figure 5 The height of the first nanopillar 121a is the same as the height of the second nanopillar 121b. In some possible embodiments, the heights of multiple nanopillars 121 within the same focusing partition Q are all the same, so the heights of each nanopillar 121 in the metasurface lens 120 can be equal, thereby facilitating the manufacture of the metasurface lens 120.

[0051] The size of the orthographic projection of the first nanopillar 121a onto the substrate 110 is different from the size of the orthographic projection of the second nanopillar 121b onto the substrate 110. Here, since the first focusing zone Q1 where the first nanopillar 121a is located is used to focus the first color light, and the second focusing zone Q2 where the second nanopillar 121b is located is used to focus the second color light, and the first color light and the second color light are different colors, that is, the first color light and the second color light have different wavelengths, in order to achieve the same focusing depth, the first nanopillar 121a and the second nanopillar 121b require different phases. By adjusting the size of the orthographic projections of the first nanopillar 121a and the second nanopillar 121b onto the substrate 110, the adjusted phase of the incident light in the metasurface lens 120 can meet the requirements.

[0052] The dimensions of the orthographic projection of the nanopillar 121 onto the substrate 110 are related to the shape and structure of the nanopillar 121. The nanopillar 121 can be a cylindrical structure or a square pillar structure, but this application is not limited to these. When the nanopillar 121 is a cylindrical structure, the dimensions of its orthographic projection onto the substrate 110 can be the diameter of the nanopillar 121. When the nanopillar 121 is a square pillar structure, its orthographic projection onto the substrate 110 is rectangular, and the dimensions of this projection can be the length and width of the rectangle.

[0053] In some possible implementations, the dimensions of the orthographic projections of each nanopillar 121 in the first focusing partition Q1 onto the substrate 110, and the dimensions of the orthographic projections of each nanopillar 121 in the second focusing partition onto the substrate 110 can be simulated.

[0054] In the second exemplary embodiment, please refer to Figure 7 , Figure 7 This is a schematic diagram of another image sensor structure provided in an embodiment of this application. The size of the orthographic projection of the first nanopillar 121a onto the substrate 110 is the same as the size of the orthographic projection of the second nanopillar 121b onto the substrate 110. For example, when the nanopillar 121 is a cylindrical structure, the diameter of the first nanopillar 121a is the same as the diameter of the second nanopillar 121b. When the nanopillar 121 is a square prism structure, the lengths of the orthographic projections of the first nanopillar 121a and the second nanopillar 121b onto the substrate 110 are the same, and the widths of the orthographic projections of the first nanopillar 121a and the second nanopillar 121b onto the substrate 110 are the same.

[0055] The heights of the first nanopillar 121a and the second nanopillar 121b are different. Here, the higher the nanopillar 121, the more incident light it collects, and the longer the light takes to pass through it, thus achieving a higher focusing effect. Therefore, by adjusting the heights of the first nanopillar 121a and the second nanopillar 121b, this embodiment of the application can adapt the focusing effect of the first nanopillar 121a to the first focusing partition Q1 for the first color light, and the focusing effect of the second nanopillar 121b to the second focusing partition Q2 for the second color light. This allows for consistent focusing depth of light received by various types of photosensitive units 130, thereby improving image quality.

[0056] In some possible implementations, the wavelength of the first color light is greater than the wavelength of the second color light, and the height of the first nanopillar 121a is greater than the height of the second nanopillar 121b. For example, the first color light can be red light, and the second color light can be green light. Alternatively, the first color light can be red light, and the second color light can be blue light. Or, the first color light can be green light, and the second color light can be blue light.

[0057] Here, for a focusing partition Q with the same structure, the different refractive indices of light of different wavelengths within the focusing partition Q result in different focusing depths for light of different wavelengths. For example, a focusing partition Q with the same structure has a greater focusing depth for light with longer wavelengths. Therefore, in this embodiment, for the first color light with a longer wavelength, the height of the corresponding first nanopillar 121a can be set to be larger to improve the focusing effect of the first focusing partition Q, thereby reducing the focusing depth of the first color light. This allows the focusing depths of the first color light and the second color light to be consistent, thus improving image quality.

[0058] It should be noted that in the first exemplary embodiment and the second exemplary embodiment, at least one parameter of the shape, spacing and orientation of the first nanopillar 121a and the second nanopillar 121b can be consistent, so as to avoid these parameters affecting the focusing effect of the first focusing partition Q1 and the second focusing partition Q2, thereby achieving more precise light adjustment.

[0059] In some possible implementations, the nanopillars 121 are cylindrical, and the diameter of the nanopillars 121 ranges from 50 nm to 200 nm. And / or, the height of the nanopillars 121 ranges from 200 nm to 1000 nm. The distance between adjacent nanopillars 121 can be determined based on the size of the focusing partition Q and the number of nanopillars 121 within the focusing partition Q. For example, the distance between adjacent nanopillars 121 can range from 0.2 μm to 0.5 μm, for example, 0.3 μm, or 0.2 μm, or 0.5 μm.

[0060] In some possible implementations, the nanopillar 121 is a cylindrical structure made of any one of silicon, gallium nitride, titanium oxide, and silicon nitride.

[0061] For some possible implementations, please refer to Figure 8 , Figure 8 This is a three-dimensional structural schematic diagram of a metasurface lens provided in an embodiment of this application. The metasurface lens 120 may further include: a substrate 122, on which a plurality of nanopillars 121 may be distributed, the substrate 122 serving to support the plurality of nanopillars 121. The material of the substrate 122 may be an optically transparent material, so that light modulated by the nanopillars 121 can pass through the substrate 122 and be received by the photosensitive unit 130. For example, the material of the substrate 122 may include: glass or sapphire.

[0062] In one exemplary embodiment, please refer to Figure 9 and Figure 10 , Figure 9 This is a partial top view of a portion of the structure of another image sensor provided in this application (to clearly illustrate the structure of the photosensitive unit). Figure 9 The filter unit and metasurface lens are not shown, but the embodiments of this application are not limited to these. Figure 10 yes Figure 9 A schematic cross-sectional view of the provided image sensor at A2-A2, wherein multiple photosensitive units 130 include three types of photosensitive units 130: a first photosensitive unit 130a for receiving a first color light, a second photosensitive unit 130b for receiving a second color light, and a third photosensitive unit 130c for receiving a third color light.

[0063] For example, the first color light can be one of red, green, and blue light; the second color light can be another of red, green, and blue light; and the third color light can be yet another of red, green, and blue light. Figure 9 For example, the first color of light can be red light, the second color of light can be green light, and the third color of light can be blue light.

[0064] The focusing zone Q corresponding to the first photosensitive unit 130a is designated as the first focusing zone Q1, the focusing zone Q corresponding to the second photosensitive unit 130b is designated as the second focusing zone Q2, and the focusing zone Q corresponding to the third photosensitive unit 130c is designated as the third focusing zone Q3. The focusing ability of the multiple nanopillars 121 within the first focusing zone Q1 for the first color light, the focusing ability of the multiple nanopillars 121 within the second focusing zone Q2 for the second color light, and the focusing ability of the multiple nanopillars 121 within the third focusing zone Q3 for the third color light are all identical. This eliminates the difference in the focusing depth of the three colors of incident light, thereby reducing the impact of chromatic aberration on image quality.

[0065] It should be noted that, Figure 10 The example shown is only the case where the light-gathering ability is adjusted by changing the size of the orthographic projection of the nanopillar 121 onto the substrate 110. For the case where the light-gathering ability is adjusted by changing the height of the nanopillar 121, please refer to [reference needed]. Figure 7 The embodiments shown will not be described in detail here.

[0066] In some possible implementations, the image sensor 100 further includes a plurality of filter units 140, which correspond to a plurality of photosensitive units 130. The filter units 140 are located on the side of the corresponding photosensitive unit 130 closer to the optical control component 120, and the orthographic projection of the filter unit 140 on the substrate 110 overlaps with the orthographic projection of the corresponding photosensitive unit 130 on the substrate 110. The filter units 140 are used to transmit light of a specific wavelength band and block light of other wavelength bands. The specific wavelength band matches the spectral response characteristics of the corresponding photosensitive unit 130, so the corresponding photosensitive unit 130 can respond to the light of that wavelength band to achieve photoelectric conversion, thereby ensuring color accuracy.

[0067] Specifically, the filter unit 140 corresponding to the first photosensitive unit 130a is the first filter unit, the filter unit 140 corresponding to the second photosensitive unit 130b is the second filter unit, and the filter unit 140 corresponding to the third photosensitive unit 130c is the third filter unit. The first filter unit is used to transmit the first color light, the second filter unit is used to transmit the second color light, and the third filter unit is used to transmit the third color light.

[0068] In some possible implementations, the image sensor 100 may further include: a deep trench isolation (DTI) structure 150, a first anti-reflective layer 160, and a mesh structure 17.

[0069] The deep trench isolation structure 150 is located on the side of the substrate 110 facing the photosensitive unit 12. The deep trench isolation structure 150 has multiple first openings, and multiple photosensitive units 130 correspond to the multiple first openings, with each photosensitive unit 130 located within its corresponding first opening. The deep trench isolation structure 150 can be used to prevent charge diffusion and optical crosstalk between adjacent photosensitive units 130. The deep trench isolation structure 150 can also be used to divide the first openings into at least two partitions, and at least two photodiodes 131 in the same photosensitive unit 130 can be distributed in at least two partitions respectively.

[0070] For example, the deep trench isolation structure 150 can be made of a reflective material, which can distribute incident light to photodiodes 131 in at least two zones by physical reflection. By detecting and comparing the phase difference of the light received by at least two photodiodes 131, the focus position can be determined, thereby enabling autofocus (AF).

[0071] In one exemplary embodiment, please refer to Figure 9 , Figure 9 This is a partial top view of a portion of the structure of an image sensor provided in this application (to clearly illustrate the structure of the photosensitive unit). Figure 9 (The filter unit and metasurface lens are not shown, but this embodiment does not limit the scope of the invention.) A single photosensitive unit 130 can contain four photodiodes 131 arranged in a row and column. Correspondingly, the deep trench isolation structure 150 divides the area corresponding to the photosensitive unit 130 into four partitions, with the four photodiodes 131 distributed within each partition. This allows the four photodiodes 131 to autofocus in multiple directions. Since the metasurface lens 120 provides more precise light adjustment, it significantly improves the focusing response speed and reduces focusing delay.

[0072] The first anti-reflective layer 160 is located between the photosensitive unit 130 and the filter unit 140. The first anti-reflective layer 160 can reduce the reflectivity of light passing through the filter unit 140 when it enters the photosensitive unit 130, thereby improving the light collection rate of the image sensor 100.

[0073] A mesh structure 170 is located on the side of the first antireflective layer 160 facing away from the substrate 110. The mesh structure 170 has a plurality of second openings, and a plurality of filter units 140 correspond to the plurality of second openings, with at least a portion of the filter units 140 located within the corresponding second openings. The mesh structure 170 is used to separate the plurality of filter units 140. Exemplarily, the material of the mesh structure 170 may include silicon dioxide and tungsten.

[0074] This application's embodiments tested the sensitivity of three types of photosensitive units; please refer to [link / reference]. Figure 11 , Figure 11 yes Figure 10 A sensitivity diagram of an image sensor is provided, wherein R1, R2, R3, and R4 are four photodiodes 131 in the first photosensitive unit 130a, G1, G2, G3, and G4 are four photodiodes 131 in the second photosensitive unit 130b, and B1, B2, B3, and B4 are four photodiodes 131 in the third photosensitive unit 130c. According to the sensitivity diagram of the first photosensitive unit 130a, the four photodiodes 131 in the first photosensitive unit 130a have essentially the same sensitivity. According to the sensitivity diagram of the second photosensitive unit 130b, the four photodiodes 131 in the second photosensitive unit 130b have essentially the same sensitivity. According to the sensitivity diagram of the third photosensitive unit 130c, the four photodiodes 131 in the third photosensitive unit 130c have essentially the same sensitivity.

[0075] Therefore, after adjusting the three colors of light through the metasurface lens 120, the focusing depth of the three colors of light is consistent, which makes the intensity difference of the corresponding color light received by different types of photosensitive units 130 smaller, thus reducing the difference in sensitivity. This reduces the difference in autofocus performance of different types of photosensitive units 130, thereby improving the image quality.

[0076] This application also simulates the autofocus performance of three types of photosensitive units 130 and compares it with related technologies. Please refer to... Figure 12 and Figure 13 , Figure 12 This is a schematic diagram illustrating the autofocus performance of an image sensor provided by related technologies. Figure 13 This is a schematic diagram illustrating the autofocus performance of an image sensor provided in an embodiment of this application. Figure 12 The structure of the corresponding image sensor can be referenced. Figure 1 , Figure 13 The structure of the corresponding image sensor can be referenced. Figure 10 . Figure 12 and Figure 13 The x-axis represents the incident light tilt angle, in degrees, and the range of the incident light tilt angle is +30 degrees to... 30 degrees. Figure 12 and Figure 13 The vertical axis represents the autofocus signal, which reflects the level of sensitivity.

[0077] In this context, curves L11 and L12 correspond to the photodiodes of the left and right sections of the red photosensitive unit in the related technology, respectively; curves L21 and L22 correspond to the photodiodes of the left and right sections of the green photosensitive unit in the related technology, respectively; and curves L31 and L32 correspond to the photodiodes of the left and right sections of the blue photosensitive unit in the related technology, respectively. For the same photosensitive unit, when the autofocus signals of the photodiodes in the left and right sections are the same, that is, at the curve intersection point, it can be indicated that the focus position meets the requirements. Figure 12 It can be seen that the intersection points of the three types of photosensitive units are not aligned, and the angle range of the intersection point area is large. The intersection point B2 corresponding to the green photosensitive unit falls at 0 degrees, while the intersection points B1 corresponding to the red photosensitive unit and B3 corresponding to the blue photosensitive unit are both offset by 0 degrees. This indicates that the autofocus performance of different color photosensitive units varies greatly.

[0078] Curves L41 and L42 correspond to the photodiodes of the left and right partitions of the first photosensitive unit in this embodiment, respectively; curves L51 and L52 correspond to the photodiodes of the left and right partitions of the second photosensitive unit in this embodiment, respectively; and curves L61 and L62 correspond to the photodiodes of the left and right partitions of the third photosensitive unit in this embodiment, respectively. Figure 13 It can be seen that after adjusting the focusing depth of the incident light by using a metasurface lens, the intersection point B4 corresponding to the first photosensitive unit, the intersection point B5 corresponding to the second photosensitive unit, and the intersection point B6 corresponding to the third photosensitive unit all fall at 0 degrees. This indicates that the embodiments of this application can improve the uniformity of autofocus performance of different types of photosensitive units by using a metasurface lens, thereby improving the image quality.

[0079] The image sensor provided in this application embodiment can be applied to camera modules. Please refer to [link / reference]. Figure 14 , Figure 14 This is a schematic diagram of incident light for an image sensor provided in an embodiment of this application. In the camera module 000, the lens assembly 200 is used to receive light reflected from the object to be photographed and to direct the received external light into the image sensor 100. Figure 10The diagram illustrates the chief ray angle (CRA) of incident light from the lens assembly 200 to the photosensitive surface of the image sensor 100. Except for the central photosensitive zone of the image sensor 100, the incident light from other photosensitive zones enters the image sensor 100 at an angle, with the angle increasing the further away from the central photosensitive zone. This results in differences in sensitivity within the photosensitive units of different photosensitive zones. The chief ray angle is directly related to the size of the image sensor 100 and the focal length of the lens assembly 200. With a fixed focal length, as the size of the image sensor 100 increases, the chief ray angle of the edge photosensitive zones of the image sensor 100 also increases.

[0080] Please refer to the relevant technologies. Figure 15 , Figure 15 This is a schematic diagram of another image sensor structure provided by related technologies. For the region corresponding to oblique incident light, the center of the orthogonal projection of the filter unit 340 on the substrate 310 is offset from the center of the orthogonal projection of the photosensitive unit 330 on the substrate 310, and the center of the orthogonal projection of the microlens 350 on the substrate 310 is offset from the center of the orthogonal projection of the photosensitive unit 330 on the substrate 310, so as to reduce the light loss of oblique incident light.

[0081] However, on the one hand, setting the offset of the photosensitive unit 330 and the microlens 350 has a limited effect on correcting oblique incident light. On the other hand, the degree of offset of the photosensitive unit 330 and the microlens 350 is usually set based on only one type of photosensitive unit 330. Therefore, the sensitivity differences within other types of photosensitive units 330 still exist, resulting in poor uniformity of different types of photosensitive units 330.

[0082] In this embodiment, the metasurface lens 120 offers greater flexibility than a microlens. By adjusting the structure and arrangement of the multiple nanopillars 121 in each focusing zone Q, each focusing zone Q can provide more precise light adjustment. In some possible implementations, for the focusing zone Q corresponding to the same type of photosensitive unit 130, the distribution pattern of the multiple nanopillars 121 in the focusing zone Q within the region where the principal angle is not 0 can differ from the distribution pattern of the multiple nanopillars 121 in the focusing zone Q within the region where the principal angle is 0. This allows the metasurface lens 120 to not only optimize the focusing path of light of different colors, thereby eliminating the influence of chromatic aberration, but also optimize the focusing path of light in different regions.

[0083] In summary, this application provides an image sensor in which the optical control component has multiple focusing zones. The multiple focusing elements in the focusing zones can converge the incident light in the corresponding areas. Since different types of photosensitive units receive different colors of light, the structure of the multiple focusing elements in different focusing zones can be matched with the characteristic light received by the corresponding type of photosensitive unit, so that the focusing depth of different colors of light after being focused by the optical control component is the same. This can reduce the difference in the focusing position of the characteristic light received by different types of photosensitive units, and further reduce the difference in intensity distribution of incident light entering different types of photosensitive units, thereby improving the imaging quality.

[0084] Secondly, embodiments of this application also provide a camera module, which includes a lens assembly and an image sensor, wherein the image sensor is the image sensor provided in any of the above embodiments. The camera module may also include other optical elements, such as reflective components, infrared filters, etc., and embodiments of this application do not limit this.

[0085] Since the camera module includes the image sensor provided in the above embodiments, the camera module can also have a similar effect, that is, it can improve the image quality.

[0086] Thirdly, this application also provides an electronic device, which includes the camera module provided in the above embodiments. This electronic device may include: smartphones, tablets, advanced driver assistance cameras, smart home monitoring systems, multi-lens devices, wearable devices, digital cameras, cloud-based photography equipment, human-computer interaction platforms, and other devices with camera functions.

[0087] Since the electronic device includes the camera module provided in the above embodiments, it can also have a similar effect, namely, it can improve image quality.

[0088] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0089] In this application, the term "at least one of A and B" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, "at least one of A and B" can represent three cases: A exists alone, A and B exist simultaneously, and B exists alone. Similarly, "at least one of A, B, and C" indicates that seven relationships can exist, representing seven cases: A exists alone, B exists alone, C exists alone, A and B exist simultaneously, A and C exist simultaneously, C and B exist simultaneously, and A, B, and C exist simultaneously.

[0090] It should be noted that the dimensions of layers and regions may be exaggerated in the accompanying drawings for clarity. Furthermore, it is understood that when an element or layer is referred to as being "on" another element or layer, it can be directly on the other element, or there may be intermediate layers. Additionally, it is understood that when an element or layer is referred to as being "below" another element or layer, it can be directly below the other element, or there may be more than one intermediate layer or element. Furthermore, it is also understood that when a layer or element is referred to as being "between" two layers or two elements, it can be the only layer between the two layers or two elements, or there may be more than one intermediate layer or element. Similar reference numerals throughout indicate similar elements.

[0091] In this application, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "multiple" refers to two or more unless otherwise expressly defined.

[0092] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An image sensor, characterized in that, The image sensor includes: a substrate, an optical control component, and multiple photosensitive units; The plurality of photosensitive units are located on the same side of the substrate, and the plurality of photosensitive units include at least two types of photosensitive units, and the different types of photosensitive units are used to receive light of different colors; The optical control component is located on the side of the plurality of photosensitive units away from the substrate. The optical control component has a plurality of light-concentrating partitions arranged in an array, and a plurality of light-concentrating elements are distributed in each light-concentrating partition. The plurality of light-concentrating zones correspond to the plurality of photosensitive units, and the orthographic projection of the light-concentrating zone on the substrate overlaps with the orthographic projection of the corresponding photosensitive unit on the substrate; different colors of light are focused to the same depth after being focused by the optical control component.

2. The image sensor according to claim 1, characterized in that, The optical control component is a metasurface lens, and the light-concentrating element is a nanopillar. Multiple nanopillars in each light-concentrating zone are arranged in an array.

3. The image sensor according to claim 2, characterized in that, The plurality of photosensitive units include: a plurality of first photosensitive units and a plurality of second photosensitive units of different types, wherein the first photosensitive units are used to receive a first color light and the second photosensitive units are used to receive a second color light; the light-gathering zone corresponding to the first photosensitive unit is a first light-gathering zone and the light-gathering zone corresponding to the second photosensitive unit is a second light-gathering zone; Each nanopillar within the first focusing zone corresponds one-to-one with a nanopillar within the second focusing zone. For the first nanopillar within the first focusing zone and the second nanopillar within the second focusing zone, the distribution position of the first nanopillar within the first focusing zone is the same as the distribution position of the second nanopillar within the second focusing zone. The first nanopillar is any one of the nanopillars distributed within the first focusing zone, and the second nanopillar is the nanopillar within the second focusing zone that corresponds to the first nanopillar. The distribution pattern of the multiple nanopillars in the first focusing zone is different from that in the second focusing zone.

4. The image sensor according to claim 3, characterized in that, The dimensions of the orthographic projection of the first nanopillar onto the substrate are the same as the dimensions of the orthographic projection of the second nanopillar onto the substrate; the heights of the first nanopillar and the second nanopillar are different.

5. The image sensor according to claim 4, characterized in that, The wavelength of the first color light is greater than the wavelength of the second color light, and the height of the first nanopillar is greater than the height of the second nanopillar.

6. The image sensor according to claim 3, characterized in that, The height of the first nanopillar is the same as the height of the second nanopillar; the size of the orthographic projection of the first nanopillar onto the substrate is different from the size of the orthographic projection of the second nanopillar onto the substrate.

7. The image sensor according to any one of claims 2-6, characterized in that, The nanopillars are cylindrical, and the diameter of the nanopillars ranges from 50 nanometers to 200 nanometers; and / or, the height of the nanopillars ranges from 200 nanometers to 1000 nanometers.

8. The image sensor according to any one of claims 2-6, characterized in that, The nanopillars are cylindrical structures made of any one of the following materials: silicon, gallium nitride, titanium oxide, and silicon nitride.

9. The image sensor according to any one of claims 3-6, characterized in that, The image sensor further includes: a plurality of filter units, which correspond to the plurality of photosensitive units. The filter units are located on the side of the corresponding photosensitive unit that is close to the optical control component, and the orthographic projection of the filter unit on the substrate overlaps with the orthographic projection of the corresponding photosensitive unit on the substrate. The filter unit corresponding to the first photosensitive unit is a first filter unit, and the filter unit corresponding to the second photosensitive unit is a second filter unit; the first filter unit is used to transmit the first color light, and the second filter unit is used to transmit the second color light.

10. The image sensor according to any one of claims 1-6, characterized in that, Within the same focusing zone, at least some of the focusing elements have different sizes of their orthogonal projections onto the substrate.

11. A camera module, characterized in that, The camera module includes a lens assembly and an image sensor, wherein the image sensor is the image sensor according to any one of claims 1 to 10.

12. An electronic device, characterized in that, The electronic device includes the camera module as described in claim 11.

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