Image sensor, camera module, and electronic device

Abstract

Embodiments of the present application relate to the technical field of imaging. Disclosed are an image sensor, a camera module, and an electronic device, used for improving the light utilization rate of the image sensor and improving the spectral splitting effect of light of a second color. The image sensor comprises a photosensitive layer, a dielectric layer, and a metasurface array layer. The photosensitive layer comprises photosensitive units, each photosensitive unit is provided with a first color channel, two second color channels and a third color channel, and a line connecting the centers of the first color channel and the third color channel intersects a line connecting the centers of the two second color channels. The metasurface array layer comprises metasurface units, and each metasurface unit is configured to disperse incident light and respectively transmit light of different colors to the corresponding color channels. Each metasurface unit comprises second microstructures located on the second color channels. In an orthographic projection on a reference plane, each second microstructure is axially symmetric about a first direction and axially symmetric about a second direction. The two second microstructures are transposes of each other within an image matrix.

Description

Image sensor, camera module and electronic device

[0001] The present application claims priority to the Chinese patent application No. 202411231784.9, filed on September 3, 2024, entitled "Image sensor, camera module and electronic device", the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the field of imaging technology, and in particular to an image sensor, a camera module and an electronic device. BACKGROUND

[0003] An image sensor is a device that converts an optical image into an electronic signal, and is widely used in electronic devices such as digital cameras and mobile phones. In recent years, image sensors have developed from charge coupled device (CCD) image sensors to complementary metal oxide semiconductor (CMOS) image sensors, which are lower in cost and have effectively improved noise problems.

[0004] The photoelectric conversion element of a COMS image sensor can convert a light signal into an electrical signal, but the photoelectric conversion element itself cannot distinguish the frequency of light (i.e., cannot distinguish the color of light). Therefore, a color filter is usually provided on the photoelectric conversion element to obtain a colored picture. However, the color filter filters light, and only a portion of the light reaches the photoelectric conversion element to be converted into an electrical signal, resulting in low light utilization. Therefore, how to improve the light utilization of the COMS image sensor has become a technical problem to be solved. SUMMARY

[0005] Embodiments of the present application provide an image sensor, a camera module and an electronic device for enhancing the light utilization of the image sensor.

[0006] To achieve the above-mentioned purpose, the embodiments of the present application adopt the following technical solutions:

[0007] In a first aspect, an image sensor, for example, a CMOS image sensor, is provided. The image sensor includes a photosensitive layer, a dielectric layer, and a metasurface array layer. The dielectric layer is on the photosensitive layer, and the metasurface array layer is on the dielectric layer. The photosensitive layer includes a plurality of photosensitive units. Each photosensitive unit has a first color channel, two second color channels, and a third color channel. A line connecting the center of the first color channel and the center of the third color channel intersects a line connecting the centers of the two second color channels. The metasurface array layer includes a metasurface unit on each photosensitive unit. Each metasurface unit is configured to disperse incident light and transmit light of different colors to corresponding color channels of the photosensitive unit. Each metasurface unit includes a second microstructure on each second color channel. In an orthogonal projection on a reference plane, the second microstructure is symmetrically arranged about a first direction axis and symmetrically arranged about a second direction axis. The two second microstructures in the same metasurface unit are transposes of each other in an image matrix. The reference plane is perpendicular to the thickness direction of the photosensitive layer. The first direction is the arrangement direction of the first color channel and the second color channel. The second direction is the arrangement direction of the second color channel and the third color channel. The first direction and the second direction intersect.

[0008] The image sensor provided by some embodiments of the present application can disperse incident light and direct the dispersed light of different colors to corresponding color channels by arranging a metasurface array layer on a photosensitive layer, using the strong dispersion characteristics of the metasurface array layer. Compared with the arrangement of a color filter alone, the light (for example, first color light and second color light) that is originally filtered and absorbed by a certain color filter can be directed to other color channels (for example, the first color channel and the second color channel) other than the color channel below the color filter, and then received by a photoelectric conversion element in the other color channel, thereby improving the light amount of the image sensor, enhancing the photosensitive capability of the image sensor, and enhancing the light utilization rate or energy utilization rate of the image sensor.

[0009] Further, on this basis, on the one hand, the imaging quality of an output image can be effectively improved when an electronic device to which the image sensor is applied is in a low-illumination scene. On the other hand, the image sensor can support a smaller pixel size (i.e., a smaller target surface size) at the same resolution, thereby supporting the reduction in height of a camera module to which the image sensor is applied.

[0010] In addition, the second microstructure in the metasurface unit can have a relatively accurate mapping relationship with the second color channel in the photosensitive layer, and the dispersion effect of the second color light can be enhanced, and the dispersed second color light can be accurately transmitted to the corresponding second color channel, thereby further improving the imaging quality of the output image.

[0011] In a possible design manner of the first aspect, the number of the simply connected regions in the second microstructure ranges from 4 to 16 in the orthogonal projection on the reference plane. In this way, the second microstructure can cooperate with other microstructures to achieve a better light dispersion effect.

[0012] In a possible design manner of the first aspect, the duty cycle of the second microstructure ranges from 1% to 50%. In this way, the dispersion effect of the second color light can be improved in the process in which the light incident on the metasurface unit is dispersed by the metasurface unit, and the imaging quality of the output image can be improved.

[0013] In a possible design manner of the first aspect, the metasurface unit further includes a first microstructure located on the first color channel. The first microstructure has C4 symmetry in the orthogonal projection on the reference plane. In this way, the color channel in the photosensitive layer can have a relatively accurate mapping relationship with the first microstructure in the metasurface array layer, the first microstructure and the second microstructure can cooperate with each other to ensure that the light incident on the metasurface unit can be accurately dispersed by the metasurface unit, and the dispersion effect of the first color light can be enhanced, and the dispersed first color light can be accurately transmitted to the corresponding first color channel to improve the imaging quality of the output image.

[0014] In a possible design manner of the first aspect, the number of the simply connected regions in the first microstructure ranges from 1 to 18 in the orthogonal projection on the reference plane. In this way, the first microstructure can cooperate with other microstructures to achieve a better light dispersion effect.

[0015] In a possible design manner of the first aspect, the duty cycle of the first microstructure ranges from 3% to 75%. In this way, the dispersion effect of the first color light can be improved in the process in which the light incident on the metasurface unit is dispersed by the metasurface unit, and the imaging quality of the output image can be improved.

[0016] In a possible design manner of the first aspect, the metasurface unit further includes: a third microstructure located on the third color channel. In the orthographic projection on the reference plane, the third microstructure has C4 symmetry, and the third microstructure is different from the first microstructure. In this way, the metasurface array layer can have better light splitting effect, so that the metasurface unit can more accurately split light, and different colors of light dispersed can be more accurately transmitted to the corresponding color channel. Moreover, the metasurface unit can avoid being difficult to accurately deflect and separate the first color light and the third color light, and the first color channel and the third color channel can avoid being difficult to accurately receive the first color light and the third color light, respectively. In this way, the imaging quality of the output image can be greatly improved.

[0017] In a possible design manner of the first aspect, in the orthographic projection on the reference plane, the number of simply connected regions in the third microstructure ranges from 1 to 15. In this way, the third microstructure can cooperate with other microstructures to achieve better light splitting effect.

[0018] In a possible design manner of the first aspect, the duty cycle of the third microstructure is less than or equal to 38%. In this way, during the process in which the metasurface unit disperses light incident on itself, the dispersion effect of the third color light can be improved, and the imaging quality of the output image can be improved.

[0019] In a possible design manner of the first aspect, the photosensitive layer and the metasurface array layer are both polygons. The diagonal length D of the metasurface array layer satisfies:

[0020] D=D0-2Htanθ, where θ=sin -1 (nsinθ0);

[0021] D0 is the diagonal length of the photosensitive layer, H is the distance between the metasurface array layer and the photosensitive layer, n is the equivalent refractive index of the structure between the metasurface array layer and the photosensitive layer, and θ0 is the maximum value of the principal angle.

[0022] By limiting the relationship between the diagonal length D of the metasurface array layer and the diagonal length D0 of the photosensitive layer, the different principal angles on each color channel in the photosensitive layer can be better matched.

[0023] In a possible design manner of the first aspect, the distance between the metasurface array layer and the photosensitive layer ranges from 0.5 μm to 2.5 μm. In this way, the metasurface array layer can provide sufficient optical path for different colors of light dispersed, so that different color channels can more accurately receive light of the corresponding color.

[0024] In a possible design manner of the first aspect, along the thickness direction of the photosensitive layer, the center of the metasurface array layer and the center of the photosensitive layer coincide. The size L of the metasurface array layer in the first direction satisfies:

[0025] The size W of the metasurface array layer in the second direction satisfies:

[0026] Wherein, L0 is the size of the photosensitive layer in the first direction, and W0 is the size of the photosensitive layer in the second direction.

[0027] In this way, the mapping relationship between each color channel in the photosensitive layer and each microstructure in the metasurface array layer can be more accurate, and the accuracy of the metasurface array layer in directing and deflecting light of different colors to a specific color channel can be improved.

[0028] In a possible design manner of the first aspect, the size p of the metasurface unit satisfies:

[0029] Wherein, p0 is the size of the color channel.

[0030] In a possible design manner of the first aspect, the orthographic projection of the metasurface unit on the reference plane is located within the orthographic projection range of the photosensitive unit on the reference plane, or the orthographic projection of the metasurface unit on the reference plane partially overlaps with the orthographic projection of the photosensitive unit on the reference plane.

[0031] In a possible design manner of the first aspect, the metasurface unit further includes a filling medium part surrounding the second microstructure. The refractive index of the material of the second microstructure is greater than the refractive index of the material of the filling medium part. Further, the filling medium part also surrounds other microstructures in the metasurface unit. In this way, it can be ensured that the metasurface unit can have good light splitting effect, and can accurately disperse the incident light incident on the metasurface unit, and deflect the dispersed first color light, second color light and third color light to the corresponding color channels, respectively.

[0032] In a possible design manner of the first aspect, the refractive index of the material of the second microstructure ranges from 1.6 to 2.6, and the refractive index of the material of the filling medium part ranges from 1 to 1.6. The refractive index of the material of the second microstructure and the refractive index of the material of the filling medium part are not both 1.6.

[0033] In a possible design manner of the first aspect, the material of the second microstructure includes at least one of silicon nitride, titanium oxide or gallium nitride, and the material of the filling medium part includes air or silicon oxide.

[0034] In a possible design of the first aspect, the height of the second microstructure ranges from 0.3 μm to 0.8 μm in the thickness direction of the photosensitive layer. In this way, the second microstructure can have a better light splitting effect. Further, the height of other microstructures in the metasurface unit can also range from 0.3 μm to 0.8 μm.

[0035] In a possible design of the first aspect, the image sensor further includes a microlens array layer located on a side of the metasurface array layer away from the photosensitive layer. The microlens array layer includes microlenses located on the metasurface units. In this way, the microlens array layer can be used to pre-modulate the incident light, so that the angle range of the incident light falls within a specific angle range, thereby enabling the metasurface units to receive more light, improving the performance of the metasurface units, further enhancing the light utilization of the image sensor, and improving the resolution and clarity of the image sensor, reducing image blur and distortion.

[0036] In a possible design of the first aspect, the image sensor further includes a filter array layer located between the photosensitive layer and the dielectric layer. The filter array layer includes first color filters located on the first color channels, second color filters located on the second color channels, and third color filters located on the third color channels. In this way, after the different colors of light are respectively deflected to the color filters by the metasurface array layer, the light of non-specific colors can be filtered out, thereby reducing the optical crosstalk between different color channels, improving the color reproduction and dynamic range of the image sensor, and benefiting the color accuracy of imaging.

[0037] In a possible design of the first aspect, the image sensor further includes an anti-reflection layer located between the photosensitive layer and the dielectric layer. In this way, the reflection of light can be reduced, and the light utilization of the image sensor can be further improved.

[0038] In a possible design of the first aspect, the image sensor further includes an anti-reflection layer located between the photosensitive layer and the dielectric layer. In this way, the reflection of light can be reduced, and the light utilization of the image sensor can be further improved.

[0039] In a possible design of the first aspect, the image sensor further includes an anti-reflection layer located between the photosensitive layer and the dielectric layer. In this way, the reflection of light can be reduced, and the light utilization of the image sensor can be further improved.

[0040] The technical effects brought by any of the designs of the second aspect to the third aspect can be refer to the technical effects brought by the different designs of the first aspect, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0041] FIG. 1 is an architecture diagram of an electronic device according to an embodiment of the present application;

[0042] FIG. 2 is a structural diagram of an electronic device according to an embodiment of the present application;

[0043] FIG. 3 is an exploded view of a camera module according to an embodiment of the present application;

[0044] FIG. 4 is a sectional structural diagram of an image sensor according to an embodiment of the present application;

[0045] FIG. 5 is a structural diagram of a filter array layer and a photoelectric conversion element according to an embodiment of the present application;

[0046] FIG. 6 is a perspective structural diagram of an image sensor according to an embodiment of the present application;

[0047] FIG. 7 is a sectional structural diagram of an image sensor according to an embodiment of the present application;

[0048] FIG. 8 is a top view structural diagram of a photosensitive layer and a photosensitive unit according to an embodiment of the present application;

[0049] FIG. 9 is a sectional structural diagram of another image sensor according to an embodiment of the present application;

[0050] FIG. 10 is a sectional structural diagram of still another image sensor according to an embodiment of the present application;

[0051] FIG. 11 is a partial structural diagram of an image sensor according to an embodiment of the present application;

[0052] FIG. 12 is a top view structural diagram of the image sensor shown in FIG. 11;

[0053] FIG. 13 is a top view of a partial structure of an image sensor according to an embodiment of the present application;

[0054] FIG. 14 is a top view of a partial structure of another image sensor according to an embodiment of the present application;

[0055] FIG. 15 is a sectional structural diagram of still another image sensor according to an embodiment of the present application;

[0056] FIG. 16 is a partial structural diagram of another image sensor according to an embodiment of the present application;

[0057] FIG. 17 is a sectional structural diagram of still another image sensor according to an embodiment of the present application;

[0058] FIG. 18 is a sectional structural diagram of still another image sensor according to an embodiment of the present application;

[0059] FIG. 19 is a sectional structural diagram of still another image sensor according to an embodiment of the present application;

[0060] FIG. 20 is a sectional structure diagram of another image sensor according to an embodiment of the present application;

[0061] FIG. 21 is a sectional structure diagram of another image sensor according to an embodiment of the present application;

[0062] FIG. 22 is a comparison curve diagram of light splitting effects of an image sensor on different wavelengths of light according to an embodiment of the present application;

[0063] FIG. 23 is a comparison curve diagram of light splitting effects of another image sensor on different wavelengths of light according to an embodiment of the present application. DETAILED DESCRIPTION

[0064] The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments of the present application.

[0065] In the description of the present application, “a plurality of” means two or more than two, unless otherwise specified. “At least one” or similar expressions mean any combination of these items, including any combination of single or multiple. For example, at least one of a, b or c can mean a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0066] In addition, in order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, the same items or similar items with basically the same function and role are distinguished by using “first”, “second”, “third” and the like. Those skilled in the art can understand that “first”, “second”, “third” and the like do not limit the quantity and execution order, and “first”, “second”, “third” and the like do not necessarily mean different. At the same time, in the embodiments of the present application, “exemplary” or “for example” means to serve as an example, illustration or description. Any embodiment or design scheme described as “exemplary” or “for example” in the embodiments of the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Rather, the use of “exemplary” or “for example” is intended to present the relevant concept in a specific manner, for understanding.

[0067] In the embodiments of the present application, unless otherwise specified and limited, the term “connection” can be a direct mechanical connection or electrical connection, or an indirect mechanical connection or electrical connection through an intermediate medium. The mechanical connection here can not limit whether it is used for transmitting electrical signals, and the electrical connection is used for transmitting electrical signals.

[0068] In the embodiments of this application, the terms "vertical" and "parallel" respectively indicate approximately vertical and approximately parallel within a certain error range. This error range can be a range where the deviation angle relative to absolute verticality and absolute parallelism is less than or equal to 5°, 8°, or 10°, respectively, and is not specifically limited here.

[0069] This application describes exemplary embodiments with reference to cross-sectional views and / or plan views as idealized exemplary drawings. In the drawings, the thickness of layers and regions is enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as limited to the shapes of the regions shown in this application, but rather include shape deviations due to, for example, manufacturing processes. For example, etched regions shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the regions of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0070] Furthermore, the architecture and scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of architecture and the emergence of new scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0071] Some embodiments of this application provide an electronic device that can be applied in fields such as security, photography and videography, automotive electronics, or industrial machine vision. This electronic device may include a handheld device, an in-vehicle device, a wearable device, a computing device, or other processing devices connected to a wireless modem.

[0072] For example, the electronic devices in the embodiments of this application may be digital cameras, cellular phones, smartphones, personal digital assistant (PDA) computers, tablet computers, laptop computers, machine type communication (MTC) terminals, point of sale (POS) terminals, in-vehicle computers, head-mounted devices, wearable devices (such as wristbands, smartwatches, etc.), security equipment, virtual reality (VR) devices, augmented reality (AR) devices, and other electronic devices with imaging functions.

[0073] FIG. 1 is an architecture diagram of an electronic device according to an embodiment of the present application. As shown in FIG. 1, the electronic device 1000 can include a camera module 100 and a processor 200 electrically connected. The camera module 100 includes a lens assembly 110 and an image sensor 120. The camera module 100 is electrically connected to the processor 200, for example, through the image sensor 120.

[0074] The image sensor 120 can also be referred to as a photosensitive chip, a photosensitive element, etc. For example, the image sensor 120 can include a plurality of photoelectric conversion elements that generate electric charges after receiving light, i.e., can convert optical signals into electrical signals.

[0075] The processor 200 can include an analog-to-digital (A / D) converter 210 and a digital signal processor 220. The analog-to-digital converter 210 is an analog signal-to-digital signal converter, which converts analog electrical signals into digital electrical signals.

[0076] During photographing of the electronic device 1000, light (which can also be referred to as an optical signal) reflected by an object to be photographed can converge on the image sensor 120 through the lens assembly 110. The image sensor 120 can convert the optical signal into an analog electrical signal and transmit the analog electrical signal to the processor 200. The analog-to-digital converter 210 in the processor 200 can receive the analog electrical signal and convert it into a digital electrical signal, which is transmitted to the digital signal processor 220. The digital signal processor 220 can process the digital electrical signal, for example, by performing a series of complex mathematical algorithm operations to optimize the data electrical signal, and finally output an image.

[0077] Optionally, the processor 200 can further include an analog signal preprocessor 230 configured to output the analog electrical signal transmitted by the image sensor 120 to the analog-to-digital converter 210 after pre-processing.

[0078] For the convenience of description, the electronic device is taken as a mobile phone as an example for illustration, which cannot be considered as a specific limitation on the structure of the electronic device. FIG. 2 is a structural diagram of an electronic device according to an embodiment of the present application. FIG. 2(a) is a front view of the electronic device, and FIG. 2(b) is a bottom view of the electronic device. Those skilled in the art can understand that the architecture of the electronic device shown in FIG. 2 does not limit the electronic device, and the electronic device can include more or fewer components than those shown in FIG. 2, or can combine some of the components shown in FIG. 2, or can be arranged differently from the components shown in FIG. 2.

[0079] In some examples, in combination with (a) and (b) in FIG. 2, the electronic device 1000 includes a housing 300 and a display screen 400. Among them, the housing 300 can include a middle frame 310 and a back cover 320, and the display screen 400 and the back cover 320 are respectively installed on the two opposite sides of the middle frame 310.

[0080] Among them, the display screen 400 is used to display images, and of course, the display screen 400 can also integrate a touch function. Optionally, the display screen 400 can be a liquid crystal display (LCD), or an organic light-emitting diode (OLED) display screen, a quantum dot light-emitting diode (QLED) display screen, a mini light-emitting diode (Mini LED) display screen, or a micro light-emitting diode (Micro LED) display screen, etc.

[0081] The above-mentioned middle frame 310 includes a bearing plate and a frame 311 around the bearing plate. In some examples, in combination with (a) and (b) in FIG. 2, the electronic device 1000 further includes a front camera assembly 500, a rear camera assembly 600, a mainboard 700, a processor 200, a memory 800, and a battery 900, etc. devices arranged on the bearing plate.

[0082] As shown in (a) of FIG. 2, a front camera hole is provided in the display screen 400. The above-mentioned front camera assembly 500 is located between the display screen 400 and the bearing plate, for example, and a part of the front camera assembly 500 is exposed through the front camera hole. External light can be incident on the front camera assembly 500 through the front camera hole and be collected by the front camera assembly 500.

[0083] As shown in (b) of FIG. 2, at least one rear camera hole is provided in the back cover 320. The rear camera assembly 600 is located on the side of the bearing plate away from the display screen 400, for example. For example, the rear camera assembly 600 is located between the bearing plate and the back cover 320 as a whole, and a part of the rear camera assembly 600 is exposed through the rear camera hole; external light can be incident on the rear camera assembly 600 through the rear camera hole and be collected by the rear camera assembly 600. For another example, a part of the rear camera assembly 600 is located between the bearing plate and the back cover 320, and the other part extends out of the housing 300 through the rear camera hole; external light can be directly incident on the rear camera assembly 600 and be collected by the rear camera assembly 600.

[0084] Optionally, the rear camera assembly 600 includes at least one camera module 610, which can be a standard camera module, a long-focus camera module, a wide-angle camera module, an ultra-long-focus camera module, or an ultra-wide-angle camera module, for example. Further, the rear camera assembly 600 can further include a flash module 620, for example.

[0085] The mainboard 700 is disposed between the bearing plate and the rear cover 320, and the processor 200 and the memory 800 are fixed on the mainboard 700. The display screen 400, the front camera assembly 500, and the rear camera assembly 600 are coupled to the processor 200, for example. The memory 800 is configured to store computer program code including computer instructions. The processor 200 is configured to invoke the computer instructions to cause the electronic device 1000 to perform corresponding operations, for example, causing the display screen 400 to display a target image, causing the front camera assembly 500 and the rear camera assembly 600 to capture the target image, and the like.

[0086] The battery 900 is disposed between the bearing plate and the rear cover 320 and is electrically connected to the mainboard 700, and is configured to supply power to the electronic device 1000.

[0087] In some examples, the electronic device 1000 can further include one or more of an antenna module, a mobile communication module, a sensor module, a motor, a microphone module, a loudspeaker module, and the like. These functional modules can be electrically connected to the processor 200 to transmit signals.

[0088] Some embodiments of the present application also provide a camera module, which can be applied to the electronic device described above. In some examples, the camera module can be used as the front camera assembly 500 shown in (a) of FIG. 2, or as the camera module 610 of the rear camera assembly 600 shown in (b) of FIG. 2. The application scenarios of the camera module described above are not limited by the embodiments of the present application.

[0089] FIG. 3 is an exploded view of a camera module according to an embodiment of the present application. In some examples, as shown in FIG. 3, the camera module 100 includes a lens assembly 110 and an image sensor 120, and the lens assembly 110 is located on the light-receiving side of the image sensor 120. Here, the light-receiving side refers to the side of the image sensor 120 that receives light. The light collected by the lens assembly 110 can be transmitted to the image sensor 120. For example, the optical axis of the lens assembly 110 and the optical axis of the image sensor 120 can coincide.

[0090] Continuing to refer to FIG. 3, the camera module 100 can further include an image sensor driving module 130, a lens driving module 140, an adhesive layer 150, an optical element 160, and a circuit board 170.

[0091] The image sensor 120 can be disposed on an image sensor driving module 130, and the image sensor driving module 130 can drive the image sensor 120 to move. The lens driving module 140 is annularly disposed on the lens assembly 110, and the lens driving module 140 can drive the lens assembly 110 to move or tilt in the axial direction (i.e., the extension direction of the optical axis) to achieve optical image stabilization, optical focusing, aberration adjustment, and the like. The lens driving module 140 can be fixed to the image sensor driving module 130 by means of an adhesive layer 150.

[0092] The optical element 160, for example, includes a filter. The optical element 160 can be disposed between the image sensor 120 and the lens assembly 110 and opposite the image sensor 120. External light passing through the lens assembly 110 can be incident on the image sensor 120 after passing through the optical element 160. The optical element 160 can filter stray light in the light passing through the lens assembly 110, so that the image captured by the camera module 100 is more realistic, thereby improving the quality of the camera module 100.

[0093] The circuit board 170, for example, is a flexible circuit board. One end of the circuit board 170 can be electrically connected to the image sensor driving module 130, and the other end can be electrically connected to the processor 200. The circuit board 170 can transmit the electrical signal converted by the image sensor 120 to the processor 200 for processing, and finally output an image.

[0094] It can be understood that the performance of the image sensor 120 affects the quality of the final output image.

[0095] FIG. 4 is a sectional view of an image sensor according to an embodiment of the present application. The image sensor, for example, is a CMOS image sensor. In some examples, as shown in FIG. 4, the image sensor 120 includes a wiring layer 1 and a photodiode layer 2 disposed on the wiring layer 1.

[0096] Referring back to FIG. 4, the photodiode layer 2 is provided with an isolation structure and a plurality of photoelectric conversion elements 2a. The isolation structure is disposed between two adjacent photoelectric conversion elements 2a to isolate the two adjacent photoelectric conversion elements 2a. Each photoelectric conversion element 2a is configured to receive light incident from a side surface thereof away from the wiring layer 1 and convert the received light into an electrical signal. Optionally, the photoelectric conversion element 2a can be a photodiode. The wiring layer 1, for example, includes a plurality of metal wiring layers, which are used to form a logic circuit, including but not limited to an amplification circuit, an analog-to-digital conversion circuit, other related processing circuits, and the like. The wiring layer 1 can also be referred to as a circuit layer.

[0097] The photoelectric conversion element 2a converts light into an electrical signal, which can be transmitted to the wiring layer 1. The logic circuit in the wiring layer 1 can process the electrical signal, and then provide the processed electrical signal to other devices (e.g., the circuit board 170 and the processor 200).

[0098] The photoelectric conversion element 2a itself cannot distinguish the frequency of light (i.e., cannot distinguish the color of light), so the final image is black and white.

[0099] In one possible implementation, referring to FIG. 4, the image sensor 120 further includes a color filter array layer 3, which includes a plurality of color filters 3a, each of which is arranged opposite to a photoelectric conversion element 2a.

[0100] In FIG. 5(a), the color filter array layer 3 is shown in a top view. For example, as shown in FIG. 5(a), the plurality of color filters 3a includes a plurality of first color filters 31, a plurality of second color filters 32, and a plurality of third color filters 33.

[0101] Further, FIG. 5(b) shows the structure of the first color filter 31, the second color filter 32, the third color filter 33, and the corresponding photoelectric conversion element 2a, respectively.

[0102] Each color filter 3a is used to filter the light incident thereto and allow light of a specific color to pass through. For example, as shown in FIG. 5(b), the first color filter 31 can transmit light of a first color and filter light of a second color and a third color; the second color filter 32 can transmit light of the second color and filter light of the first color and the third color; and the third color filter 33 can transmit light of the third color and filter light of the first color and the second color. In this way, each photoelectric conversion element 2a can receive light of a specific color, and the plurality of photoelectric conversion elements 2a can cooperate to obtain a color image.

[0103] However, due to the filtering of light by each color filter 3a, the transmittance (or energy transmittance) of light is low, resulting in a large amount of light information not being effectively utilized, and reducing the light utilization rate.

[0104] Based on this, some embodiments of the present application improve the structure of the image sensor. Specifically, FIG. 6 shows a perspective view of an image sensor, FIG. 7, FIG. 9 and FIG. 10 respectively show a cross-sectional view of an image sensor, and FIG. 8 shows a top view of a photosensitive layer and a photosensitive unit. Specifically, FIG. 8(a) shows a top view of a photosensitive layer, and FIG. 8(b) and FIG. 8(c) respectively show a top view of a photosensitive unit. Specifically, the cross-sectional lines of FIG. 9 and FIG. 10 are first extended along the first direction X and then extended along the second direction Y. That is, the structures shown in FIG. 9 and FIG. 10 are composed of a cross-sectional structure along the first direction X and a cross-sectional structure along the second direction Y.

[0105] In some examples, as shown in FIG. 6 and FIG. 7, the image sensor 120 includes a wiring layer 1, a photosensitive layer 2, a dielectric layer 4 and a metasurface array layer 5. In the case of applying the image sensor 120 to the camera module 100 described above, the photosensitive layer 2 is located on the side of the wiring layer 1 close to the lens assembly 110, the dielectric layer 4 is located on the side of the photosensitive layer 2 close to the lens assembly 110, and the metasurface array layer 5 is located on the side of the dielectric layer 4 close to the lens assembly 110. As for the wiring layer 1, please refer to the relevant description above, which will not be repeated here.

[0106] For example, as shown in FIG. 6 and FIG. 7, the photosensitive layer 2 has a plurality of color channels 21a. As shown in FIG. 8(a), the plurality of color channels 21a are arranged in multiple rows and multiple columns. Each row of color channels 21a includes a plurality of color channels 21a arranged along the first direction X, and each column of color channels 21a includes a plurality of color channels 21a arranged along the second direction Y, and the first direction X and the second direction Y intersect (e.g., perpendicular). For example, the number of color channels 21a included in each row of color channels 21a and the number of color channels 21a included in each column of color channels 21a are equal.

[0107] The plurality of color channels 21a can constitute a plurality of photosensitive units 21, and the number of color channels 21a included in each photosensitive unit 21 can be equal or not equal. The embodiments of the present application take the example of equal number of color channels 21a included in each photosensitive unit 21 for illustrative purposes. Optionally, each photosensitive unit 21 includes four color channels 21a.

[0108] Continuing to refer to (a) of FIG. 8, the four color channels 21a included in each photosensitive unit 21 can be one first color channel 211, two second color channels 212, and one third color channel 213, respectively. The line connecting the center of the first color channel 211 and the center of the third color channel 213 intersects the line connecting the centers of the two second color channels 212. That is, in the quadrilateral formed by the lines connecting the centers of the four color channels 21a of the photosensitive unit 21, the first color channel 211 and the third color channel 213 are located at two opposite corners, and the two second color channels 212 are located at the other two opposite corners.

[0109] Further, as shown in (a) of FIG. 8, in the same row of color channels 21a, the first color channels 211 and the second color channels 212 are alternately arranged, or the second color channels 212 and the third color channels 213 are alternately arranged. In the same column of color channels 21a, the first color channels 211 and the second color channels 212 are alternately arranged, or the second color channels 212 and the third color channels 213 are alternately arranged. For example, the above-mentioned first direction X can also be considered as the arrangement direction of the first color channels 211 and the second color channels 212, and the second direction Y can also be considered as the arrangement direction of the second color channels 212 and the third color channels 213.

[0110] The above-mentioned first color channel 211, second color channel 212, and third color channel 213 are respectively configured to receive light of different colors. For example, the first color channel 211 is configured to receive first color light, the second color channel 212 is configured to receive second color light, and the third color channel 213 is configured to receive third color light.

[0111] Optionally, the first color light is red (R) light, the second color light is green (G) light, and the third color light is blue (B) light. In this case, the above-mentioned image sensor 120 is, for example, an image sensor in an RGGB mode.

[0112] Optionally, the first color light is red light, the second color light is yellow (Y) light, and the third color light is blue light. In this case, the above-mentioned image sensor 120 is, for example, an image sensor in an RYYB mode.

[0113] Of course, the above-mentioned first color light, second color light, and third color light are not limited to the above-mentioned two combinations, and correspondingly, the above-mentioned image sensor 120 is also not limited to the above-mentioned two modes.

[0114] Each color channel 21a in the photosensitive layer 2 can have one or more photoelectric conversion elements 2a. The number of photoelectric conversion elements 2a in different color channels 21a can be the same or different. Optionally, the number of photoelectric conversion elements 2a in each color channel 21a shown in (a) of FIG. 8 is the same. For example, as shown in (c) of FIG. 8, each color channel 21a has one photoelectric conversion element 2a. For another example, as shown in (b) of FIG. 8, each color channel 21a has four photoelectric conversion elements 2a.

[0115] For example, as shown in FIGS. 6 and 7, the medium layer 4 covers the photosensitive layer 2 in a planar shape. The material of the medium layer 4 can include inorganic medium materials, such as, but not limited to, silicon oxide, silicon nitride, etc. Alternatively, the material of the medium layer 4 can include organic medium materials, such as, but not limited to, photoresists (e.g., SU-8 photoresist, HSQ photoresist), etc.

[0116] The medium layer 4 can be transparent to light. For example, the refractive index of the medium layer 4 ranges from 1.4 to 2.3. Alternatively, the refractive index of the medium layer 4 can be 1.4, 1.5, 1.7, 1.9, 2.1, or 2.3, etc.

[0117] For example, as shown in FIGS. 6 and 7, the super surface array layer 5 includes a plurality of super surface units 51, which are respectively located on the plurality of photosensitive units 21. That is, the plurality of super surface units 51 and the plurality of photosensitive units 21 correspond to each other one by one, and each photosensitive unit 21 is provided with one super surface unit 51 away from the wiring layer 1. For example, each photosensitive unit 21 and its corresponding super surface unit 51 are at least partially arranged opposite to each other.

[0118] The super surface array layer 5 has strong dispersion characteristics and different deflection effects on different colors of light (or different wavelengths of light), which can realize the function of directing and deflecting different colors of light (corresponding to the required color channels) to a specific color channel 21a. The super surface units 51 are configured to disperse incident light and transmit different colors of light to the corresponding color channels 21a in the photosensitive units 21. The medium layer 4 provides a certain optical path (i.e., a certain transmission distance for different colors of light), which facilitates the different color channels 21a to accurately receive light of a specific color.

[0119] Specifically, continuing to refer to FIG. 7, each metasurface unit 51 includes a plurality of microstructures 51a. In combination with FIG. 7, (a) of FIG. 9, and (a) of FIG. 10, after the external light (i.e., incident light) is incident on the metasurface array layer 5, the plurality of microstructures 51a in each metasurface unit 51 can cooperate with each other to refract the external light, separate out the first color light, the second color light, and the third color light, and transmit the first color light through the medium layer 4 to the corresponding first color channel 211, the second color light through the medium layer 4 to the corresponding second color channel 212, and the third color light through the medium layer 4 to the corresponding third color channel 213.

[0120] Here, the different color lights separated by the metasurface unit 51 are transmitted to the corresponding color channels 21a around the photosensitive unit 21 in addition to the corresponding color channels 21a below the photosensitive unit 21.

[0121] In this way, compared with the manner of separately arranging the filter array layer 3 shown in FIG. 4 and FIG. 5, the embodiment of the present application can use the metasurface array layer 5 (or the metasurface unit 51) to refract the light (e.g., the first color light and the second color light) that is originally filtered and absorbed by a certain color filter 3a to other color channels 21a (e.g., the first color channel 211 and the second color channel 212) other than the color channel 21a below the color filter 3a, and the light is received by the photoelectric conversion element 2a in the other color channel 21a. In this way, the light amount of the image sensor 120 can be improved, the photosensitive capability of the image sensor 120 can be enhanced, and the light utilization rate or energy utilization rate of the image sensor 120 can be enhanced.

[0122] Further, on this basis, on the one hand, in the case that the electronic device 1000 applying the image sensor 120 described above is in a low-illumination scene, the imaging quality of the output image can be effectively improved; on the other hand, the image sensor 120 described above can support a smaller pixel size (i.e., a smaller target surface size) at the same resolution, thereby supporting the reduction of the camera module 100.

[0123] Optionally, the image sensor 120 described above can include a filter array layer arranged between the photosensitive layer 2 and the medium layer 4. For the arrangement of the filter array layer, refer to the relevant description below, which is not repeated here. Of course, the arrangement of the filter array layer can also be omitted in the image sensor 120 described above.

[0124] In the case where the filter array layer is not provided, the light amount of the image sensor 120 can be further increased and the light sensing capability of the image sensor 120 can be further enhanced due to the elimination of the absorption of light by the filter array layer. In the case where the filter array layer is provided, the color accuracy of the imaging can be improved by cooperating with the metasurface array layer 5 to reduce the crosstalk between different color channels 21a.

[0125] In some examples, as shown in FIG. 11, the plurality of microstructures 51a in the metasurface unit 51 includes a second microstructure 512 located on each of the two second color channels 212. That is, on the side of each second color channel 212 away from the wiring layer 1, the light sensing layer 2 is provided with a second microstructure 512.

[0126] As shown in FIG. 12, the orthographic projection of each second microstructure 512 on the reference plane is symmetrically arranged about the first direction X axis and symmetrically arranged about the second direction Y axis. For example, as shown in FIGS. 12, 13 and 14, the second microstructure 512 can have a first symmetry axis L1 extending along the first direction X, and the orthographic projection of the second microstructure 512 on the reference plane can be folded along the first symmetry axis L1, and the patterns on both sides of the first symmetry axis L1 can coincide. The second microstructure 512 can also have a second symmetry axis L2 extending along the second direction Y, and the orthographic projection of the second microstructure 512 on the reference plane can be folded along the second symmetry axis L2, and the patterns on both sides of the second symmetry axis L2 can coincide.

[0127] Further, referring to FIGS. 12, 13 and 14, the orthographic projections of the two second microstructures 512 in the same metasurface unit 51 on the reference plane are transposed to each other in the image matrix. For example, the orthographic projections of the two second microstructures 512 on the reference plane are symmetrically arranged about the center line L3 connecting the first color channel 211 and the third color channel 213 in the image matrix. For another example, the orthographic projections of the two second microstructures 512 are symmetrically arranged about the center line L3 connecting the first color channel 211 and the third color channel 213.

[0128] For example, in the structure shown in FIG. 13, the orthographic projection of the second microstructure 512 located at the lower left corner on the reference plane includes six quadrilaterals arranged in a manner of three rows and two columns, and the image matrix thereof is, for example, The orthographic projection of the second microstructure 512 located at the upper right corner on the reference plane includes six quadrilaterals arranged in a manner of two rows and three columns, and the image matrix thereof is, for example, In addition, the orthographic projection of each second microstructure 512 on the reference plane is symmetrically arranged about the first symmetry axis L1 and symmetrically arranged about the second symmetry axis L2.

[0129] It can be understood that the opposite sides of the first color channel 211 or the third color channel 213 along the first direction X and the opposite sides along the second direction Y are provided with the second color channel 212, and the second color channel 212 is located on the opposite sides of the center line of the adjacent first color channel 211 and third color channel 213, respectively. The plurality of second microstructures 512 in the metasurface unit 51 of the embodiment of the application can have a more accurate mapping relationship between the second color channel 212 in the photosensitive layer 2 and the second microstructure 512 in the metasurface array layer 5 by adopting the above arrangement, and in the process of dispersing the light incident to itself by each metasurface unit 51, the dispersion effect of the second color light is enhanced, and it is ensured that the dispersed second color light can be accurately transmitted to the corresponding second color channel 212, thereby improving the imaging quality of the output image.

[0130] In some examples, the second microstructure 512 is, for example, a topological structure. As shown in FIG. 11, the second microstructure 512 has a plurality of simply connected regions D2; the simply connected region D2 is manifested as: in this region, any simple closed curve can be continuously contracted into a point without leaving the region. Further, in the structure shown in FIG. 12, a simply connected region D2 is, for example, equivalent to a nanopillar structure; in the structures shown in FIGS. 12, 13 and 14, a simply connected region D2 is, for example, equivalent to an overhead view figure. Among them, the shapes of the plurality of simply connected regions D2 of the second microstructure 512 can be the same or different; the different simply connected regions D2 are independent and not connected.

[0131] For example, the number of simply connected regions D2 of the second microstructure 512 ranges from 4 to 16. Alternatively, the number of simply connected regions D2 of the second microstructure 512 can be 4, 7, 10, 12, 13, 15 or 16, etc.

[0132] For example, as shown in FIG. 12, the second microstructure 512 has 5 simply connected regions D2. In the structure shown in FIG. 12, the shapes of the five simply connected regions D2 are the same, and each is circular. One of the simply connected regions D2 is located in the middle, and the other four simply connected regions D2 are arranged around the simply connected region D2.

[0133] For another example, as shown in FIG. 13, the second microstructure 512 has 6 simply connected regions D2. In the structure shown in FIG. 13, two of the simply connected regions D2 have the same shape and are rectangular; the other four simply connected regions D2 have the same shape and are square. The six simply connected regions D2 are arranged in a manner of three rows and two columns, or in a manner of two columns and three rows.

[0134] For example, as shown in FIG. 14, the second microstructure 512 has 8 single-connected regions D2. In the structure shown in FIG. 14, the eight single-connected regions D2 are of the same shape, and are all circular, and are arranged in three rows and three columns.

[0135] With the above arrangement, it can be ensured that the second microstructure 512 itself can be symmetrically arranged about the symmetry axis extending along the first direction X, and about the symmetry axis extending along the second direction Y, and that the two second microstructures 512 in the same hyper-surface unit 51 can be transposed to each other on the image matrix data; and it can also be ensured that the second microstructure 512 can cooperate with other microstructures 51a to achieve a better light splitting effect.

[0136] In some examples, the duty cycle of the second microstructure 512 described above ranges from 1% to 50%. As shown in FIG. 12, the "duty cycle" refers to, for example, the ratio between the area of the orthogonal projection of the second microstructure 512 on the reference plane (e.g., the sum of the areas of the five circular patterns in FIG. 12) and the area of the orthogonal projection of the second color channel 212 on the reference plane.

[0137] Here, the range of the duty cycle of the second microstructure 512 is related to, for example, the size of the second color channel 212 in the first direction X. The duty cycle of the second microstructure 512 is described below in connection with the size of the second color channel 212 in the first direction X. The size of the second color channel 212 in the first direction X is, for example, the same as its size in the second direction Y.

[0138] Alternatively, the size of the second color channel 212 in the first direction X is 0.7 μm, and correspondingly, the range of the duty cycle of the second microstructure 512 is 3% to 31%. For example, the duty cycle of the second microstructure 512 is 3%, 10%, 18%, 22%, 26%, or 31%, etc.

[0139] Alternatively, the size of the second color channel 212 in the first direction X is 1.0 μm, and correspondingly, the range of the duty cycle of the second microstructure 512 is 8% to 40%. For example, the duty cycle of the second microstructure 512 is 8%, 13%, 20%, 28%, 33%, or 40%, etc.

[0140] Alternatively, the size of the second color channel 212 in the first direction X is 1.12 μm, and correspondingly, the range of the duty cycle of the second microstructure 512 is 1% to 26%. For example, the duty cycle of the second microstructure 512 is 1%, 5%, 9%, 14%, 24%, or 26%, etc.

[0141] Optionally, the second color channel 212 has a size of 1.22 pm in the first direction X, and correspondingly, the duty cycle of the second microstructure 512 ranges from 4% to 50%. For example, the duty cycle of the second microstructure 512 is 4%, 19%, 27%, 34%, 45%, or 50%, etc.

[0142] Optionally, the second color channel 212 has a size of 1.4 pm in the first direction X, and correspondingly, the duty cycle of the second microstructure 512 ranges from 2% to 31%. For example, the duty cycle of the second microstructure 512 is 2%, 11%, 16%, 23%, 25%, or 31%, etc.

[0143] In this way, in the process of each hyper-surface unit 51 dispersing the light incident thereon, the dispersion effect of the second color light is improved, and the imaging quality of the output image is improved.

[0144] In some examples, as shown in FIG. 11, along the thickness direction of the photosensitive layer 2, i.e., along the third direction Z, the height of the second microstructure 512 ranges from 0.3 pm to 0.8 pm. Optionally, the height of the second microstructure 512 can be 0.3 pm, 0.45 pm, 0.56 pm, 0.68 pm, 0.71 pm, or 0.8 pm, etc.

[0145] In this way, the second microstructure 512 can have a better light splitting effect.

[0146] In some examples, as shown in FIG. 11, the plurality of microstructures 51a in each hyper-surface unit 51 further includes a first microstructure 511 located on the first color channel 211. That is, on the side of each first color channel 211 of the photosensitive layer 2 away from the wiring layer 1, a first microstructure 511 is arranged.

[0147] As shown in FIG. 12, the orthographic projection of the first microstructure 511 on the reference plane has C4 symmetry. For example, as shown in FIGS. 12, 13, and 14, the orthographic projection of the first microstructure 511 on the reference plane has a center of symmetry P, and the orthographic projection of the first microstructure 511 on the reference plane coincides with the original figure after being rotated by 90°, 180°, or 270° about the center of symmetry. The first microstructure 511 has a symmetry axis extending along the third direction Z, and the first microstructure 511 coincides with the original structure after being rotated by 90°, 180°, or 270° about the symmetry axis. The third direction Z is, for example, the thickness direction of the photosensitive layer 2, and the reference plane is perpendicular to the third direction Z.

[0148] For example, the shape of the orthographic projection of the first microstructure 511 on the reference plane includes, but is not limited to, one or a combination of a circle, a cross, a polygon, etc.

[0149] Since the normal projection of the first microstructure 511 on the reference plane has C4 symmetry, the first microstructure 511 can have different deflection effects (or modulation effects) on light of different wavelengths, and the modulation effects are independent of polarization.

[0150] It can be understood that, based on the arrangement manners of the first color channel 211, the second color channel 212, and the third color channel 213, the first microstructure 511 in the metasurface unit 51 of the embodiment of the present application can have a relatively accurate mapping relationship with the color channel 21a in the photosensitive layer 2 and the first microstructure 511 in the metasurface array layer 5 by using the above setting manner, and the first microstructure 511 and the second microstructure 512 can cooperate with each other to ensure that each metasurface unit 51 can accurately disperse light incident thereon; moreover, it is also beneficial to enhance the dispersion effect of the first color light and ensure that the dispersed first color light can be accurately transmitted to the corresponding first color channel 211 to improve the imaging quality of the output image.

[0151] In some examples, the first microstructure 511 is, for example, a topological structure. As shown in FIG. 11, the first microstructure 511 has a simply connected region D1; for the simply connected region D1, reference can be made to the related description of the simply connected region D2 above, which will not be repeated here. The number of the simply connected regions D1 possessed by the first microstructure 511 can be one or multiple.

[0152] For example, the number of the simply connected regions D1 possessed by the first microstructure 511 ranges from 1 to 18. Alternatively, the number of the simply connected regions D1 possessed by the first microstructure 511 can be 1, 2, 5, 8, 11, 13, or 18, etc. In the case where the number of the simply connected regions D1 possessed by the first microstructure 511 is multiple, the shapes of the multiple simply connected regions D1 can be the same or different.

[0153] For example, as shown in FIG. 12, the first microstructure 511 has one simply connected region D1. In the structure shown in FIG. 12, the shape of the simply connected region D1 is a cross shape.

[0154] For another example, as shown in FIG. 13, the first microstructure 511 has five simply connected regions D1. In the structure shown in FIG. 13, the shape of one of the simply connected regions D1 is a square shape; the other four simply connected regions D1 are respectively arranged at the four corner positions of the simply connected region D1, and the shapes of the four simply connected regions D1 are the same and are all “L” shapes.

[0155] For example, as shown in FIG. 14, the first micro structure 511 has 5 single-connected regions D1. In the structure shown in FIG. 14, one of the single-connected regions D1 is in the shape of a square ring, and has protrusions at four corners; the other four single-connected regions D1 are respectively arranged between two adjacent protrusions, and the four single-connected regions D1 are in the same shape and are all in the shape of a heptagon.

[0156] With the above arrangement, the first micro structure 511 can have C4 symmetry by itself, and can cooperate with other micro structures 51a to achieve a better light splitting effect.

[0157] In some examples, the duty cycle of the first micro structure 511 is in the range of 3%-75%. As shown in FIG. 12, the "duty cycle" refers to, for example, the ratio between the area of the orthographic projection of the first micro structure 511 on the reference plane and the area of the orthographic projection of the first color channel 211 on the reference plane.

[0158] Here, the range of the duty cycle of the first micro structure 511 is related to, for example, the size of the first color channel 211 in the first direction X. The duty cycle of the first micro structure 511 is schematically described below in relation to the size of the first color channel 211 in the first direction X. The size of the first color channel 211 in the first direction X is, for example, the same as its size in the second direction Y.

[0159] Alternatively, the size of the first color channel 211 in the first direction X is 0.7 μm, and the range of the duty cycle of the first micro structure 511 is 14%-38%. For example, the duty cycle of the first micro structure 511 is 14%, 18%, 21%, 28%, 32%, or 38%, etc.

[0160] Alternatively, the size of the first color channel 211 in the first direction X is 1.0 μm, and the range of the duty cycle of the first micro structure 511 is 7%-75%. For example, the duty cycle of the first micro structure 511 is 7%, 19%, 33%, 46%, 61%, or 75%, etc.

[0161] Alternatively, the size of the first color channel 211 in the first direction X is 1.12 μm, and the range of the duty cycle of the first micro structure 511 is 4%-52%. For example, the duty cycle of the first micro structure 511 is 4%, 11%, 20%, 31%, 40%, or 52%, etc.

[0162] Optionally, the size of the first color channel 211 in the first direction X is 1.22 μm, and correspondingly, the duty cycle of the first microstructure 511 ranges from 8% to 42%. For example, the duty cycle of the first microstructure 511 is 8%, 17%, 22%, 29%, 33%, or 42%, etc.

[0163] Optionally, the size of the first color channel 211 in the first direction X is 1.4 μm, and correspondingly, the duty cycle of the first microstructure 511 ranges from 3% to 40%. For example, the duty cycle of the first microstructure 511 is 3%, 10%, 19%, 26%, 34%, or 40%, etc.

[0164] In this way, in the process that each metasurface unit 51 disperses the light incident to itself, the dispersion effect of the first color light is improved, and the imaging quality of the output image is improved.

[0165] The first microstructure 511 has the same height as the second microstructure 512, for example. Correspondingly, the height of the first microstructure 511 also ranges from 0.3 μm to 0.8 μm along the third direction Z. Optionally, the height of the first microstructure 511 is 0.3 μm, 0.45 μm, 0.56 μm, 0.68 μm, 0.71 μm, or 0.8 μm, etc.

[0166] In this way, the first microstructure 511 can have a better light splitting effect.

[0167] Optionally, in some embodiments, as shown in FIG. 11, the third color channel 213 away from the wiring layer 1 can not be provided with a third microstructure. That is, the plurality of microstructures 51a in the metasurface unit 51 only include the first microstructure 511 and the second microstructure 512. The first microstructure 511 and the second microstructure 512 cooperate to realize the dispersion of the first color light, the second color light, and the third color light.

[0168] Of course, as shown in FIG. 13 and FIG. 14, the third color channel 213 away from the wiring layer 1 can also be provided with a third microstructure 513. Based on this, the plurality of microstructures 51a in the metasurface unit 51 can also include the third microstructure 513, which is located on the third color channel 213. The first microstructure 511, the second microstructure 512, and the third color channel 213 cooperate to realize the dispersion of the first color light, the second color light, and the third color light.

[0169] The orthographic projection of the third microstructure 513 on the reference plane has C4 symmetry. For the third microstructure 513, please refer to the related description of the first microstructure 511 above, which will not be repeated here.

[0170] Further, as shown in FIG. 13 and FIG. 14, the normal projection of the third microstructure 513 on the reference plane is different from the normal projection of the first microstructure 511 on the reference plane.

[0171] It can be understood that the wavelength of the first color light is different from the wavelength of the third color light. Based on the arrangement mode of the first color channel 211, the second color channel 212 and the third color channel 213 in the photosensitive unit 21, the third microstructure 513 is arranged in the above manner, so that each super surface unit 51 in the super surface array layer 5 has better light splitting effect, ensures that each super surface unit 51 can more accurately split light, and ensures that different colors of light dispersed can be more accurately transmitted to the corresponding color channel 21a; Moreover, it can avoid the situation that the super surface unit 51 is difficult to accurately deflect and separate the first color light and the third color light, and avoid the phenomenon that the first color channel 211 and the third color channel 213 are difficult to accurately receive the first color light and the third color light respectively. This is conducive to greatly improving the imaging quality of the output image.

[0172] In some examples, the third microstructure 513 is, for example, a topological structure. As shown in FIG. 13 and FIG. 14, the third microstructure 513 has a simply connected region D3; for the simply connected region D3, please refer to the related description of the simply connected region D1 in the above, which will not be repeated here. Wherein, the number of the simply connected region D3 possessed by the third microstructure 513 can be one or more.

[0173] For example, the number of the simply connected region D3 possessed by the third microstructure 513 ranges from 1 to 15. Alternatively, the number of the simply connected region D3 possessed by the third microstructure 513 can be 1, 3, 5, 9, 11, 13 or 15, etc. In the case that the number of the simply connected region D3 possessed by the third microstructure 513 is more than one, the shapes of the plurality of simply connected regions D3 can be the same or different.

[0174] For example, as shown in FIG. 13, the third microstructure 513 has one simply connected region D3. In the structure shown in FIG. 13, the shape of the simply connected region D3 is a square.

[0175] For another example, as shown in FIG. 14, the third microstructure 513 has one simply connected region D3. In the structure shown in FIG. 14, the shape of the simply connected region D3 is an octagon.

[0176] In the above manner, it can be ensured that the third microstructure 513 itself has C4 symmetry, and the third microstructure 513 can cooperate with other microstructures 51a to achieve better light splitting effect.

[0177] In some examples, the duty cycle of the third microstructure 513 is less than or equal to 38%. As shown in FIG. 13, the "duty cycle" refers to, for example, the ratio between the area of the orthographic projection of the third microstructure 513 on the reference plane and the area of the orthographic projection of the third color channel 213 on the reference plane.

[0178] Here, the range of the duty cycle of the third microstructure 513 is related to, for example, the size of the third color channel 213 in the first direction X. The duty cycle of the third microstructure 513 is schematically described below in relation to the size of the third color channel 213 in the first direction X. The size of the third color channel 213 in the first direction X is, for example, the same as its size in the second direction Y.

[0179] Optionally, the size of the third color channel 213 in the first direction X is 0.7 μm, and correspondingly, the duty cycle of the third microstructure 513 is less than or equal to 22%. For example, the duty cycle of the third microstructure 513 is 1%, 3%, 8%, 12%, 19% or 22%, etc.

[0180] Optionally, the size of the third color channel 213 in the first direction X is 1.0 μm, and correspondingly, the duty cycle of the third microstructure 513 is less than or equal to 23%. For example, the duty cycle of the third microstructure 513 is 2%, 5%, 10%, 13%, 17% or 23%, etc.

[0181] Optionally, the size of the third color channel 213 in the first direction X is 1.12 μm, and correspondingly, the duty cycle of the third microstructure 513 is less than or equal to 34%. For example, the duty cycle of the third microstructure 513 is 1%, 5%, 9%, 14%, 24% or 34%, etc.

[0182] Optionally, the size of the third color channel 213 in the first direction X is 1.22 μm, and correspondingly, the duty cycle of the third microstructure 513 is less than or equal to 38%. For example, the duty cycle of the third microstructure 513 is 4%, 11%, 16%, 24%, 30% or 38%, etc.

[0183] Optionally, the size of the third color channel 213 in the first direction X is 1.4 μm, and correspondingly, the duty cycle of the third microstructure 513 is less than or equal to 32%. For example, the duty cycle of the third microstructure 513 is 2%, 11%, 16%, 23%, 25% or 32%, etc.

[0184] In this way, in the process of dispersing the light incident to itself by each super surface unit 51, the dispersion effect of the third color light is improved, and the imaging quality of the output image is improved.

[0185] The third microstructure 513 has the same height as the second microstructure 512, for example. Correspondingly, the height of the third microstructure 513 along the third direction Z can also range from 0.3 μm to 0.8 μm. Alternatively, the height of the third microstructure 513 can be 0.3 μm, 0.45 μm, 0.56 μm, 0.68 μm, 0.71 μm, or 0.8 μm, etc.

[0186] In this way, the third microstructure 513 can have a better light splitting effect.

[0187] It can be understood that, in the same super surface unit 51, the orthographic projection shapes of the first microstructure 511, the two second microstructures 512, and the third microstructure 513 on the reference plane can be equivalent to the orthographic projection shape of the super surface unit 51 on the reference plane. The heights of the first microstructure 511, the second microstructure 512, or the third microstructure 513 can be equivalent to the height of the super surface unit 51. The orthographic projection shape of the super surface unit 51 on the reference plane and the height of the super surface unit 51 have a certain matching relationship, so that the super surface unit 51 can disperse incident light and achieve dispersion of light of different colors (or different wavelengths).

[0188] Taking the first color light as red light, the second color light as green light or yellow light, and the third color light as blue light as an example. After the light of different wavelengths passes through the super surface array layer 5, different energy distributions S M，h (λ, x, y) can be generated on the side surface of the photosensitive layer 2 away from the wiring layer 1. Each color channel 21a is composed of the light of different wavelengths with specific weights w R (λ), w G / Y (λ), and w B (λ), and thus, the FOM can be defined, and the FOM can be optimized to obtain the orthographic projection shape M of the super surface unit 51 on the reference plane and the height h of the super surface unit 51. The function is as follows:

[0189] wherein λ is the wavelength; M 511 , M 512,512 , and M 513 are the orthographic projection shapes of the first microstructure 511, the two second microstructures 512, and the third microstructure 513 on the reference plane, respectively. By optimizing the function as above, the orthographic projection shape M of the super surface unit 51 on the reference plane and the height h of the super surface unit 51 can be obtained when the FOM M，h is the largest.

[0190] The super surface unit 51 of the super surface array layer 5 can also include other structures. The following is a schematic description in conjunction with the accompanying drawings.

[0191] In some embodiments, as shown in FIG. 7, the metasurface unit 51 further comprises a filling medium part 51b surrounding each microstructure 51a. Specifically, in the case where the plurality of microstructures 51a in the metasurface unit 51 comprises the second microstructure 512, the filling medium part 51b surrounds the second microstructure 512; in the case where the plurality of microstructures 51a in the metasurface unit 51 comprises the first microstructure 511, the filling medium part 51b surrounds the first microstructure 511; in the case where the plurality of microstructures 51a in the metasurface unit 51 comprises the third microstructure 513, the filling medium part 51b surrounds the third microstructure 513.

[0192] The refractive index of the microstructure 51a and the refractive index of the filling medium part 51b are different. For example, the refractive index of the microstructure 51a is greater than the refractive index of the filling medium part 51b. That is, the refractive index of the first microstructure 511, the second microstructure 512 or the third microstructure 513 is greater than the refractive index of the filling medium part 51b.

[0193] In this way, it can be ensured that the metasurface unit 51 can have a good light splitting effect, and the incident light incident to the metasurface unit 51 can be dispersed more accurately, and the dispersed first color light, second color light and third color light can be deflected to the corresponding color channels 21a, respectively.

[0194] In some examples, each microstructure 51a in the metasurface array layer 5 is prepared and formed synchronously using the same patterning process. Correspondingly, the materials of the first microstructure 511, the second microstructure 512 and the third microstructure 513 are the same, for example, and the refractive indices of the first microstructure 511, the second microstructure 512 and the third microstructure 513 are equal, for example.

[0195] Here, the refractive index and material of each microstructure 51a in the metasurface array layer 5 are described taking the second microstructure 512 as an example.

[0196] For example, the refractive index of the material of the second microstructure 512 ranges from 1.6 to 2.6. Alternatively, the refractive index of the material of the second microstructure 512 can be 1.6, 1.8, 1.9, 2.1, 2.3 or 2.6, etc.

[0197] For example, the material of the second microstructure 512 comprises a material with a high refractive index. For example, the material of the second microstructure 512 comprises at least one of silicon nitride, titanium oxide or gallium nitride. That is, the material of the second microstructure 512 can be composed of one kind of inorganic material, or can be composed of a mixture of multiple kinds of inorganic materials. In this way, the refractive index of the second microstructure 512 can be adjusted to meet the optical design requirements of the second microstructure 512.

[0198] The material of the filling medium 51b has a refractive index in the range of 1-1.6, for example. Alternatively, the material of the second microstructure 512 can have a refractive index of 1, 1.1, 1.2, 1.3, 1.4, or 1.6, etc. In this case, the materials of the filling medium 51b and the second microstructure 512 do not have the same refractive index of 1.6.

[0199] The material of the filling medium 51b includes a material with a lower refractive index. For example, the material of the filling medium 51b includes air or silicon oxide. In this case, the material of the filling medium 51b is air, as shown in FIGS. 7, 11, etc.

[0200] It can be understood that, in the above-mentioned super surface array layer 5 and the photosensitive layer 2, a super surface unit 51 is arranged above each photosensitive unit 21. In this way, the plurality of photosensitive units 21 and the plurality of super surface units 51 can define the same shape. That is, the photosensitive layer 2 and the super surface array layer 5 have the same shape. The shape here refers to, for example, the orthographic projection shape of the photosensitive layer 2 and the super surface array layer 5 on a reference plane.

[0201] For example, the photosensitive layer 2 and the super surface array layer 5 are both polygons, including but not limited to squares, rectangles, pentagons, hexagons, etc. In the structure shown in FIG. 6, the photosensitive layer 2 and the super surface array layer 5 are both squares. The number of super surface units 51 in the super surface array layer 5 is, for example, not less than 1200x900, that is, the number of super surface units 51 in the same row along the first direction X is not less than 1200, and the number of super surface units 51 in the same column along the second direction Y is not less than 900.

[0202] FIG. 15 shows a cross-sectional structure of an image sensor along the diagonal direction thereof. As shown in FIG. 15, the photosensitive layer 2 has a diagonal length D0, and the diagonal length D0 satisfies:

[0203] In this case, L0 is the size (or length) of the photosensitive layer 2 in the first direction X, and W0 is the size (or width) of the photosensitive layer 2 in the second direction Y.

[0204] Further, the super surface array layer 5 has a diagonal length D, and the diagonal length D of the super surface array layer 5 and the diagonal length D0 of the photosensitive layer 2 satisfy:

[0205] D=D0-2Htanθ, where θ=sin -1 (nsinθ0).

[0206] In the above formula, H is the spacing between the metasurface array layer 5 and the photosensitive layer 2, n is the equivalent refractive index of the structure between the metasurface array layer 5 and the photosensitive layer 2, and θ0 is the maximum value of the chief ray angle.

[0207] For example, the spacing between the metasurface array layer 5 and the photosensitive layer 2 refers to the spacing between the side surface of the metasurface array layer 5 close to the wiring layer 1 and the side surface of the photosensitive layer 2 away from the wiring layer 1. The spacing H can be in the range of 0.5 μm to 2.5 μm. Alternatively, the spacing H can be 0.5 μm, 0.5 μm, 0.5 μm, 0.5 μm, 0.5 μm, or 2.5 μm, etc.

[0208] As shown in FIG. 7, the structure between the metasurface array layer 5 and the photosensitive layer 2, for example, refers to the dielectric layer 4; correspondingly, n is the refractive index of the dielectric layer 4. Alternatively, at least one of a filter array layer or an anti-reflection layer can also be arranged between the metasurface array layer 5 and the photosensitive layer 2; correspondingly, n is the equivalent refractive index of at least one of the filter array layer or the anti-reflection layer and the dielectric layer 4. For the filter array layer and the anti-reflection layer, please refer to the relevant description below, which will not be repeated here.

[0209] By limiting the relationship between the diagonal length D of the metasurface array layer 5 and the diagonal length D0 of the photosensitive layer 2, the different chief ray angles (CRA) on each color channel 21a in the photosensitive layer 2 can be better matched.

[0210] In some examples, as shown in FIG. 15, along the third direction Z, the center of the metasurface array layer 5 and the center of the photosensitive layer 2 coincide. In this way, the color channels 21a in the photosensitive layer 2 and the microstructures 51a in the metasurface array layer 5 can have more accurate mapping relationship, and the accuracy of the metasurface array layer 5 in directing and deflecting light of different colors to a specific color channel 21a can be improved.

[0211] Based on the relationship between the diagonal length D of the metasurface array layer 5 and the diagonal length D0 of the photosensitive layer 2, the size L of the metasurface array layer 5 in the first direction X, for example, satisfies:

[0212] And the size W of the metasurface array layer 5 in the second direction Y satisfies:

[0213] Since the diagonal length D of the metasurface array layer 5 is less than the diagonal length D0 of the photosensitive layer 2, the size L of the metasurface array layer 5 in the first direction X is less than the size L0 of the photosensitive layer 2 in the first direction X; and the size W of the metasurface array layer 5 in the second direction Y is less than the size W0 of the photosensitive layer 2 in the second direction Y.

[0214] Further, the size p (i.e. the size in the first direction X or the second direction Y) of the metasurface unit 51 satisfies:

[0215] where p0 is the size (i.e. the size in the first direction X or the second direction Y) of the color channel 21a. For example, the size p0 of the color channel 21a is in the range of 0.6 pm - 1.6 pm. i

[0216] Here, each color channel 21a can have one or more photoelectric conversion elements 2a. In the case where the color channel 21a has a plurality of photoelectric conversion elements 2a, the plurality of photoelectric conversion elements 2a are arranged in an m x m manner, for example. For example, the size (i.e. the size in the first direction X or the second direction Y, which can also be referred to as the pixel size) of a single photoelectric conversion element 2a is p1, and accordingly, the size p0 of a single color channel 21a is mp1, and the period of the color channel 21a (or the size of the photosensitive unit 21) in the photosensitive layer 2 is 2mp1. The size p of the metasurface unit 51 also satisfies:

[0217] For example, the size p of the photosensitive unit 21 is in the range of [1.99p0, 2p0]. The size of the photosensitive unit 21 is slightly smaller than the size of the metasurface unit 51, or even tends to be consistent.

[0218] In this case, a portion of the metasurface units 51 in the metasurface array layer 5 near the center can be directly opposite the corresponding photosensitive units 21; at this time, as shown in FIG. 11, in the portion of the metasurface units 51, the orthographic projection of each metasurface unit 51 on the reference plane is located within the orthographic projection range of the corresponding photosensitive unit 21 on the reference plane. A portion of the metasurface units 51 in the metasurface array layer 5 away from the center can be misaligned with the corresponding photosensitive units 21; at this time, as shown in FIG. 16, in the portion of the metasurface units 51, the orthographic projection of each metasurface unit 51 on the reference plane partially overlaps with the orthographic projection of the corresponding photosensitive unit 21 on the reference plane.

[0219] In some embodiments, the image sensor 120 provided by the embodiments of the present application can also include other structures, such as a microlens array layer, a filter array layer, or an anti-reflection layer, etc. The following will be described schematically with reference to the accompanying drawings. FIGS. 17-21 respectively show a cross-sectional structure diagram of an image sensor. The image sensor 120 can include one or more of a microlens array layer, a filter array layer, and an anti-reflection layer. The cross-sectional line of FIG. 18 first extends along the first direction X and then extends along the second direction Y, that is, the structure shown in FIG. 18 is composed of a cross-sectional structure along the first direction X and a cross-sectional structure along the second direction Y. ​

[0220] In some examples, as shown in FIG. 17, the microlens array layer 6 is located on the side of the metasurface array layer 5 away from the photosensitive layer 2. The microlens array layer 6 includes a plurality of microlenses 61 arranged in an array, each of which is located on a plurality of metasurface units 51. For example, there is a one-to-one correspondence between the plurality of microlenses 61 and the plurality of metasurface units 51, and each metasurface unit 51 has a microlens 61 arranged on the side thereof away from the photosensitive layer 2. For example, each microlens 61 is arranged at least partially opposite to the metasurface unit 51 corresponding thereto.

[0221] As shown in FIG. 18, the microlens 61 can converge the light incident thereon, so that the exit angle of the light passing through the microlens 61 is smaller than the incident angle thereof.

[0222] Based on the characteristics of the metasurface unit 51, the metasurface unit 51 can receive light within a specific angle range, in which the metasurface unit 51 can have a better light splitting effect, so that the image sensor 120 has better performance.

[0223] By arranging the microlens array layer 6 on the side of the metasurface array layer 5 away from the photosensitive layer 2, the microlens array layer 6 can be used to pre-modulate the light incident on the image sensor 120, so that the angle range of the incident light falls within the specific angle range, thereby allowing the metasurface unit 51 to receive more light, improving the performance of the metasurface unit 51, further enhancing the light utilization of the image sensor 120, and improving the resolution and clarity of the image sensor 120, reducing the blurring and distortion of the image.

[0224] In some examples, as shown in FIG. 19 and FIG. 20 in combination with (b) of FIG. 9, the above-mentioned filter array layer 3 is located between the photosensitive layer 2 and the dielectric layer 4. The filter array layer 3 includes a plurality of color filters 3a, which includes a plurality of first color filters 31, a plurality of second color filters 32, and a plurality of third color filters 33, wherein the plurality of first color filters 31 are respectively located on each first color channel 211, the plurality of second color filters 32 are respectively located on each second color channel 212, and the plurality of third color filters 33 are respectively located on each third color channel 213.

[0225] Exemplarily, the first color filters 31 and the first color channels 211 are one-to-one corresponding, and each first color channel 211 is provided with a first color filter 31 away from one side of the wiring layer 1. For example, each first color channel 211 is arranged opposite to the corresponding first color filter 31. The second color filters 32 and the second color channels 212 are one-to-one corresponding, and each second color channel 212 is provided with a second color filter 32 away from one side of the wiring layer 1. For example, each second color channel 212 is arranged opposite to the corresponding second color filter 32. The third color filters 33 and the third color channels 213 are one-to-one corresponding, and each third color channel 213 is provided with a third color filter 33 away from one side of the wiring layer 1. For example, each third color channel 213 is arranged opposite to the corresponding third color filter 33.

[0226] As shown in (b) of FIG. 9 and (b) of FIG. 10, the first color filter 31 can transmit the first color light and filter the second color light and the third color light; the second color filter 32 can transmit the second color light and filter the first color light and the third color light; and the third color filter 33 can transmit the third color light and filter the first color light and the second color light.

[0227] By arranging the filter array layer 3 between the photosensitive layer 2 and the medium layer 4, after the different color lights are respectively deflected to the color filters on the super surface array layer 5, the non-specific color light can be filtered out, thereby reducing the optical crosstalk between the different color channels 21a, improving the color restoration degree and dynamic range of the image sensor 120, and being beneficial to the color accuracy of imaging.

[0228] In some examples, as shown in FIG. 21, the anti-reflection layer 7 is arranged between the photosensitive layer 2 and the medium layer 4. In the case that the image sensor 120 further comprises the filter array layer 3, the anti-reflection layer 7 is arranged between the filter array layer 3 and the medium layer 4, for example. The anti-reflection layer 7 can be composed of multiple thin films, for example. The structure of the anti-reflection layer 7 includes multiple types, and FIG. 21 only schematically shows the position of the anti-reflection layer 7 and does not limit the specific structure of the anti-reflection layer 7.

[0229] By arranging the anti-reflection layer 7, the reflection of light can be reduced, and the light utilization rate of the image sensor 120 can be further improved.

[0230] The light splitting enhancement effect of the image sensor 120 is tested under different design parameters respectively.

[0231] Example One

[0232] The resolution of the image sensor 120 is 2608x1960, the maximum principal angle θ0 at the diagonal is 35°, and the pixel size is 1.12 μm. Among them, the first color light received by the first color channel 211 is red light, the second color light received by the second color channel 212 is green light, and the third color light received by the third color channel 213 is blue light.

[0233] Each color channel 21a in the image sensor 120 has one photoelectric conversion element 2a, and thus the size L of the metasurface array layer 5 in the first direction X is 2919.67 μm, and the size W of the metasurface array layer 5 in the second direction Y is 2194.23 μm; the metasurface array layer 5 includes 1304x980 metasurface units 51 arranged in an array, that is, along the first direction X, the number of metasurface units 51 in the same row is 1304; along the second direction Y, the number of metasurface units 51 in the same column is 980; the size p of the metasurface unit 51 is 2.239 μm. The material of the plurality of microstructures 51a in the metasurface unit 51 includes silicon nitride, and the height of the microstructure 51a is 0.6 μm; the material of the filling medium part 51b in the metasurface unit 51 includes air.

[0234] The image sensor 120 includes a filter array layer 3, and along the third direction Z, the thickness of the filter array layer 3 is 0.2 μm; the spacing between the surface of the filter array layer 3 away from the wiring layer 1 and the surface of the metasurface array layer 5 close to the wiring layer 1 is 1.3 μm; the material of the medium layer 4 includes SU-8 photoresist.

[0235] Further, in the metasurface unit 51, the orthographic projection shape (or the top view shape) of the first microstructure 511, the second microstructure 512, and the third microstructure 513 on the reference plane is as shown in FIG. 13, wherein the first microstructure 511 and the third microstructure 513 respectively have C4 symmetry and are different from each other; each second microstructure 512 is symmetrically arranged about the first direction X axis and symmetrically arranged about the second direction Y axis; and the two second microstructures 512 are transposed to each other on the image matrix.

[0236] Continuing to refer to FIG. 13, the first microstructure 511 has 5 single-connected regions D1, and the duty cycle of the first microstructure 511 is 25%; each second microstructure 512 has 6 single-connected regions D2, and the duty cycle of each second microstructure 512 is 15%; and the third microstructure 513 has 1 single-connected region D1, and the duty cycle of the third microstructure 513 is 9%.

[0237] In the embodiment, the light splitting enhancement effect of the image sensor 120 is shown in FIG. 22, in which curve one, curve two and curve three respectively represent the relationship between the intensity and wavelength of red light, green light and blue light when the super surface array layer 5 is not arranged; curve four, curve five and curve six respectively represent the relationship between the intensity and wavelength of red light, green light and blue light when the structure shown in the embodiment one is arranged. The curve graph shown in FIG. 22 is a normalized curve graph, the value represented by the vertical coordinate is a relative value, and does not represent the actual light intensity.

[0238] As can be seen from FIG. 22, in the wavelength range of 620nm-700nm, curve four is slightly higher than curve one, that is, after the super surface array layer 5 is arranged, the light splitting effect of the image sensor 120 on red light is enhanced to a certain extent. In the wavelength range of 490nm-580nm, curve five is higher than curve two, and the difference between them is large; that is, after the super surface array layer 5 is arranged, the light splitting effect of the image sensor 120 on green light is well enhanced. In the wavelength range of 440nm-470nm, curve six is higher than curve three, and the difference between them is large; that is, after the super surface array layer 5 is arranged, the light splitting effect of the image sensor 120 on blue light is well enhanced.

[0239] Further, the image sensor 120 with the above design parameters has higher light utilization or energy utilization, which is conducive to enhancing the photosensitive capability of the image sensor 120.

[0240] Embodiment two

[0241] The resolution of the image sensor 120 is 8000x6000, the maximum principal angle θ0 at the diagonal line is 15°, and the pixel size is 0.7μm. Among them, the first color light received by the first color channel 211 is red light, the second color light received by the second color channel 212 is yellow light, and the third color light received by the third color channel 213 is blue light.

[0242] Each color channel 21a in the image sensor 120 has four photoelectric conversion elements 2a arranged in two rows and two columns. Thus, the size p0 of a single color channel 21a is 1.4 μm. The size L of the metasurface array layer 5 in the first direction X is 5599.3181 μm, and the size W of the metasurface array layer 5 in the second direction Y is 4199.4886 μm; the metasurface array layer 5 includes 2000 x 1500 metasurface units 51 arranged in an array, that is, along the first direction X, the number of metasurface units 51 in the same row is 2000; along the second direction Y, the number of metasurface units 51 in the same column is 1500; the size p of the metasurface unit 51 is 2.79966 μm. The material of the plurality of microstructures 51a in the metasurface unit 51 includes silicon nitride, and the height of the microstructure 51a is 0.6 μm; the material of the filling medium part 51b in the metasurface unit 51 includes air.

[0243] The image sensor 120 includes the filter array layer 3, and along the third direction Z, the thickness of the filter array layer 3 is 0.3 μm; the spacing between the surface of the filter array layer 3 away from the wiring layer 1 and the surface of the metasurface array layer 5 close to the wiring layer 1 is 2.2 μm; the material of the medium layer 4 includes silicon oxide.

[0244] Further, in the metasurface unit 51, the orthographic projection shape (or the top view shape) of the first microstructure 511, the second microstructure 512, and the third microstructure 513 on the reference plane is shown in FIG. 14, wherein the first microstructure 511 and the third microstructure 513 respectively have C4 symmetry and are different from each other; each second microstructure 512 is symmetrically arranged about the first direction X axis and symmetrically arranged about the second direction Y axis; two second microstructures 512 are transposed to each other on the image matrix.

[0245] Continuing to refer to FIG. 14, the first microstructure 511 has 5 single-connected regions D1, and the duty cycle of the first microstructure 511 is 37.2%; each second microstructure 512 has 8 single-connected regions D2, and the duty cycle of each second microstructure 512 is 12.4%; the third microstructure 513 has 1 single-connected region D1, and the duty cycle of the third microstructure 513 is 4.7%.

[0246] In the embodiment, the light splitting enhancement effect of the image sensor 120 is shown in FIG. 23, in which curve one, curve two and curve three respectively represent the relationship between the intensity and wavelength of red light, yellow light and blue light in the case that the metasurface array layer 5 is not arranged; curve four, curve five and curve six respectively represent the relationship between the intensity and wavelength of red light, yellow light and blue light in the case that the structure shown in Embodiment Two is arranged. The curve diagram shown in FIG. 23 is a normalized curve diagram, and the value represented by the ordinate is a relative value and does not represent the actual light intensity.

[0247] As can be seen from FIG. 23, in the wavelength range of 620nm-700nm, curve four is higher than curve one, and the difference between them is large; that is, after the above-mentioned metasurface array layer 5 is arranged, the light splitting effect of the image sensor 120 on red light is well enhanced. In the wavelength range of 550nm-600nm, curve five is higher than curve two, and the difference between them is large; that is, after the above-mentioned metasurface array layer 5 is arranged, the light splitting effect of the image sensor 120 on yellow light is well enhanced. In the wavelength range of 440nm-460nm, curve six is higher than curve three, and the difference between them is large; that is, after the above-mentioned metasurface array layer 5 is arranged, the light splitting effect of the image sensor 120 on blue light is well enhanced.

[0248] Further, the image sensor 120 with the above-mentioned design parameters has higher light utilization or energy utilization, and the light sensing capability of the image sensor 120 is enhanced.

[0249] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An image sensor, characterized by, The image sensor comprises a photosensitive layer, a medium layer and a metasurface array layer; the medium layer is located on the photosensitive layer, and the metasurface array layer is located on the medium layer; The photosensitive layer comprises a plurality of photosensitive units, each photosensitive unit having a first color channel, two second color channels and a third color channel, the center line of the first color channel and the center line of the third color channel intersecting the center line of the two second color channels; The metasurface array layer comprises a metasurface unit on each photosensitive unit; the metasurface unit is configured to disperse incident light and transmit light of different colors to the corresponding color channels in the photosensitive unit; The metasurface unit comprises a second microstructure on each second color channel; in the orthographic projection on the reference plane, the second microstructure is symmetrically arranged about a first direction axis and symmetrically arranged about a second direction axis; two second microstructures are transposed on the image matrix; The reference plane is perpendicular to the thickness direction of the photosensitive layer, the first direction is the arrangement direction of the first color channel and the second color channel, the second direction is the arrangement direction of the second color channel and the third color channel, and the first direction and the second direction intersect.

2. The image sensor of claim 1, wherein, In the orthographic projection on the reference plane, the number of simply connected regions in the second microstructure ranges from 4 to 16.

3. The image sensor according to claim 1 or 2, characterized by The duty cycle of the second microstructure ranges from 1% to 50%.

4. The image sensor according to any one of claims 1 to 3, characterized in that, The metasurface unit further comprises a first microstructure on the first color channel; In the orthographic projection on the reference plane, the first microstructure has C4 symmetry.

5. The image sensor of claim 4, wherein, In the orthographic projection on the reference plane, the number of simply connected regions in the first microstructure ranges from 1 to 18.

6. The image sensor of claim 5, wherein, The duty cycle of the first microstructure ranges from 3% to 75%.

7. The image sensor according to any one of claims 4-6, wherein, The metasurface unit further comprises a third microstructure on the third color channel; In the orthographic projection on the reference plane, the third microstructure has C4 symmetry, and the third microstructure is different from the first microstructure.

8. The image sensor of claim 7, wherein, In the orthographic projection on the reference plane, the number of simply connected regions in the third microstructure ranges from 1 to 15.

9. The image sensor according to claim 7 or 8, characterized in that, The duty cycle of the third microstructure is less than or equal to 38%.

10. The image sensor according to any one of claims 1 to 9, wherein, The photosensitive layer and the metasurface array layer are both polygons; The diagonal length D of the metasurface array layer satisfies: D = D0- 2H tan θ, where θ = sin -1 (n sin θ0); D0 is the diagonal length of the photosensitive layer, H is the spacing between the metasurface array layer and the photosensitive layer, n is the equivalent refractive index of the structure between the metasurface array layer and the photosensitive layer, and θ0 is the maximum value of the principal angle.

11. The image sensor of claim 10, wherein, The spacing between the metasurface array layer and the photosensitive layer ranges from 0.5 μm to 2.5 μm.

12. The image sensor according to claim 10 or 11, characterized by Along the thickness direction of the photosensitive layer, the center of the metasurface array layer coincides with the center of the photosensitive layer; The size L of the metasurface array layer in the first direction satisfies: The size W of the metasurface array layer in the second direction satisfies: Wherein, L0 is the size of the color channel in the first direction, and W0 is the size of the color channel in the second direction.

13. The image sensor according to any one of claims 10-12, wherein, The size p of the metasurface unit satisfies: Wherein, p0 is the size of the color channel.

14. The image sensor of any one of claims 1-13, wherein, A normal projection of the metasurface unit on the reference plane is located in a normal projection range of the photosensitive unit on the reference plane; or A normal projection of the metasurface unit on the reference plane partially overlaps with a normal projection of the photosensitive unit on the reference plane.

15. The image sensor of any one of claims 1-14, wherein, The metasurface unit further comprises a filling medium part surrounding the second microstructure; A refractive index of a material of the second microstructure is greater than a refractive index of a material of the filling medium part.

16. The image sensor of claim 15, wherein, The refractive index of the material of the second microstructure ranges from 1.6 to 2.6; The refractive index of the material of the filling medium part ranges from 1 to 1.

6.

17. The image sensor of claim 15 or 16, wherein, The material of the second microstructure comprises at least one of silicon nitride, titanium oxide or gallium nitride; The material of the filling medium part comprises air or silicon oxide.

18. The image sensor of any one of claims 1-17, wherein, Along a thickness direction of the photosensitive layer, a height of the second microstructure ranges from 0.3 μm to 0.8 μm.

19. The image sensor of any one of claims 1-18, wherein, The image sensor further comprises a microlens array layer located on a side of the metasurface array layer away from the photosensitive layer; The microlens array layer comprises a microlens located on each of the metasurface units.

20. The image sensor of any one of claims 1-19, wherein, The image sensor further comprises a filter array layer located between the photosensitive layer and the medium layer; The filter array layer comprises a first color filter located on each of the first color channels, a second color filter located on each of the second color channels, and a third color filter located on each of the third color channels.

21. The image sensor of any one of claims 1-20, wherein, The image sensor further comprises an anti-reflection layer located between the photosensitive layer and the medium layer.

22. A camera module, comprising: The camera module comprises: The image sensor according to any one of claims 1-21; A lens assembly located on a light-entering side of the image sensor.

23. An electronic device, comprising: The electronic device comprises: The camera module according to claim 22; A processor electrically connected to the image sensor in the camera module.

Images