Image sensor, camera module and electronic equipment

Abstract

The invention relates to an image sensor, a camera module and electronic equipment. The image sensor comprises a first micro-lens layer, a second micro-lens layer and a plurality of photosensitive units arranged in an array. The first micro-lens layer is arranged on the light incident side of the light sensing unit and comprises a plurality of first micro-lenses arranged in an array, and the orthographic projection of each first micro-lens on the light sensing unit covers at least part of at least one light sensing unit; the second micro-lens layer is arranged on one side, opposite to the light sensing unit, of the first micro-lens layer and comprises a plurality of second micro-lenses arranged in an array, the orthographic projection of each second micro-lens on the light sensing unit covers at least part of at least two first micro-lenses, and the orthographic projection of each second micro-lens on the light sensing unit covers at least part of at least two second micro-lenses. The material refractive index of the second micro lens layer is smaller than that of the first micro lens layer. According to the image sensor, improvement of resolution, quantum efficiency and focusing performance can be well considered.

Description

Technical Field

[0001] This application relates to the field of imaging technology, and particularly to an image sensor, an imaging module, and an electronic device. Background Art

[0002] An image sensor generally includes a plurality of pixel structures arranged in an array. The pixel structure usually includes a photosensitive unit and a microlens disposed on the light incident side of the photosensitive unit. The microlens can converge incident light and improve the light utilization efficiency of the photosensitive unit. However, in a traditional image sensor, the setting of the microlens easily introduces scattering and diffraction phenomena, affecting the photosensitive performance of the image sensor. Summary of the Invention

[0003] Embodiments of this application provide an image sensor, an imaging module, and an electronic device to solve the problem that the setting of the microlens easily introduces scattering and diffraction phenomena and affects the photosensitive performance.

[0004] An image sensor includes:

[0005] A plurality of photosensitive units arranged in an array;

[0006] A first microlens layer disposed on the light incident side of the photosensitive unit and including a plurality of first microlenses arranged in an array, and the orthographic projection of each first microlens on the photosensitive unit covers at least part of at least one of the photosensitive units; and

[0007] A second microlens layer disposed on the side of the first microlens layer facing away from the photosensitive unit and including a plurality of second microlenses arranged in an array, and the orthographic projection of each second microlens on the photosensitive unit covers at least part of at least two of the first microlenses, and the refractive index of the material of the second microlens layer is less than the refractive index of the material of the first microlens layer.

[0008] An imaging module includes the image sensor according to any one of the above embodiments.

[0009] An electronic device includes the imaging module as described above.

[0010] In the above image sensor, a stacked first microlens layer and second microlens layer are provided on the light incident side of the photosensitive unit, and the refractive index of the material of the second microlens layer is less than that of the material of the first microlens layer. Thus, the second microlens layer can play a role in refractive index transition between the first microlens layer and the air medium, reducing the refractive index difference that the light passes through when incident, which is beneficial to suppressing the reflection and scattering phenomena of the light on the light incident surfaces of the first microlens and the second microlens. At the same time, the gradual transition of the refractive index is beneficial to slowing down the deflection angle of the light on the respective surfaces of the first microlens and the second microlens, which is beneficial to suppressing the generation of aberrations such as distortion and improving the imaging quality and photosensitive performance of the image sensor. The two converging effects of the first microlens and the second microlens can also improve the degree of light convergence and the utilization efficiency of the photosensitive unit for light.

[0011] In addition, the first microlenses with a relatively large arrangement density are beneficial to reducing the signal crosstalk between adjacent photosensitive units and improving the resolution of the image sensor, while the second microlenses with a relatively small arrangement density and a relatively large size are beneficial to collecting more light and suppressing the scattering and diffraction phenomena of the light, which is beneficial to improving the quantum efficiency and focusing performance of the image sensor. Through the combination of the first microlens layer and the second microlens layer, it is possible to well balance the improvement of resolution, quantum efficiency and focusing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0013] Figure 1 It is a schematic structural diagram of an electronic device in some embodiments.

[0014] Figure 2 It is a schematic structural diagram of a camera module in some embodiments.

[0015] Figure 3 It is a schematic structural diagram of a sensor in some embodiments.

[0016] Figure 4 It is a schematic structural diagram of a first microlens layer and a second microlens layer in some embodiments.

[0017] Figure 5 It is a schematic optical path diagram of a first microlens layer and a second microlens layer in some embodiments.

[0018] Figure 6 It is a schematic structural diagram of a second transition layer provided in some embodiments.

[0019] Figure 7 Schematic diagram of the structure of the first transition layer and the second transition layer in some embodiments.

[0020] Figure 8 Schematic diagram of the structure in which one second microlens covers four first microlenses in some embodiments.

[0021] Figure 9 Schematic diagram of the structure in which one second microlens covers two first microlenses in some embodiments.

[0022] Figure 10 Schematic diagram of the structure in which one first microlens covers four photosensitive units in some embodiments.

[0023] Figure 11 Schematic diagram of the structure in which the second microlens is offset relative to the first microlens in some embodiments.

[0024] Figure 12 Schematic diagram of the structure in which the first microlens is offset relative to the photosensitive unit in some embodiments.

[0025] Figure 13 Schematic diagram of other components of the electronic device in some embodiments.

[0026] Reference numerals:

[0027] 10, electronic device; 11, middle frame; 12, back plate; 13, camera module; 131, lens; 1311, lens; 20, image sensor; 21, first microlens layer; 211, first microlens; 22, second microlens layer; 221, second microlens; 23, photosensitive unit; 231, filter layer; 24, first transition layer; 25, second transition layer; 26, first direction; 27, second direction. Detailed implementation manners

[0028] To facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0029] As used herein, "electronic device" refers to a device capable of receiving and / or transmitting communication signals connected by any one or more of the following connection methods:

[0030] (1) By means of a wired connection, such as via a Public Switched Telephone Networks (PSTN), Digital Subscriber Line (DSL), digital cable, direct cable connection;

[0031] (2) By means of a wireless interface, such as a cellular network, Wireless Local Area Network (WLAN), digital television network such as DVB-H network, satellite network, AM-FM broadcast transmitter.

[0032] An electronic device configured to communicate via a wireless interface may be referred to as a "mobile terminal". Examples of mobile terminals include, but are not limited to, the following electronic devices:

[0033] (1) Satellite phone or cellular phone;

[0034] (2) A Personal Communications System (PCS) terminal that can combine cellular radio telephone with data processing, fax, and data communication capabilities;

[0035] (3) Radiotelephone, pager, Internet / Intranet access, web browser, notepad, calendar, Personal Digital Assistant (PDA) equipped with a Global Positioning System (GPS) receiver;

[0036] (4) Conventional laptop and / or palmtop receivers;

[0037] (5) Conventional laptop and / or palmtop radiotelephone transceivers, etc.

[0038] In a conventional image sensor, a microlens layer is usually disposed on the light incident side of a photosensitive unit to converge light, improve the light utilization efficiency, and enhance the photosensitivity of the image sensor. In the conventional image sensor, the microlens layer includes a plurality of microlenses arranged in an array, and usually one microlens covers one photosensitive unit, or one microlens covers four photosensitive units arranged in a two-row and two-column array. When one microlens covers one photosensitive unit, the optical signals between adjacent photosensitive units are not easily crosstalked, so that the image sensor has better image resolution. However, due to the small size of a single microlens, the surface profile of the microlens layer is relatively complex, and stray light is easily introduced due to phenomena such as scattering and diffraction, affecting the effective utilization of light, resulting in a decrease in the quantum efficiency and focusing performance of the image sensor. When one microlens covers a plurality of photosensitive units, although the quantum efficiency and focusing performance of the image sensor can be improved, the optical signals between adjacent photosensitive units are easily crosstalked, resulting in a decrease in the image resolution of the image sensor. Therefore, it is difficult for the conventional image sensor to have good photosensitivity.

[0039] To solve the above problems, the present application provides an image sensor, a camera module, and an electronic device.

[0040] Please refer to Figure 1 、 Figure 2 and Figure 3 , Figure 1 which shows a schematic structural diagram of an electronic device 10 in some embodiments of the present application, Figure 2 which shows a schematic structural diagram of a camera module 13 in some embodiments of the present application, Figure 3 which shows a schematic structural diagram of an image sensor 20 in some embodiments of the present application. The image sensor 20 provided by the present application can form a camera module 13 with a lens 131. The camera module 13 includes but is not limited to being used in electronic devices 10 such as smart phones, tablet computers, and e-readers. In the embodiments of the present application, a smart phone is taken as an example.

[0041] The electronic device 10 further includes a middle frame 11, a back plate 12, and a display panel. The back plate 12 and the display panel are disposed on two opposite sides of the middle frame 11 and enclose a receiving space with the middle frame 11. The camera module 13 is disposed in the receiving space and collects light through a light passing hole provided in the back plate 12, so that the camera module 13 can be a rear camera of the electronic device 10. Of course, the camera module 13 can also collect light through a light passing hole provided in the display panel, so that the camera module 13 is a front camera of the electronic device 10.

[0042] The camera module 13 includes a lens 131 and an image sensor 20. The lens 131 may include one or more lenses 1311 with optical power. The lens 131 can collect light and conduct the light to the image sensor 20. The photosensitive units 23 on the image sensor 20 can convert the optical signal into an electrical signal and transmit it to the main board in the electronic device 10 or a chip dedicated to processing image signals in the electronic device 10, so as to convert the electrical signal into an image and display it on the display panel of the electronic device 10.

[0043] Reference Figure 3 and Figure 4 As shown, in some embodiments, the image sensor 20 includes a first microlens layer 21, a second microlens layer 22, and a plurality of photosensitive units 23 arranged in an array. Any applicable photoelectric conversion device such as a photodiode is provided in the photosensitive unit 23. The photosensitive unit 23 is used to receive light from the lens 131 and convert the optical signal into an electrical signal. Each photosensitive unit 23 may correspond to one pixel, or a plurality of photosensitive units 23 correspond to one pixel.

[0044] The plurality of photosensitive units 23 together form the photosensitive structure layer of the image sensor 20. The first microlens layer 21 is disposed on the light incident side of the photosensitive structure layer. The first microlens layer 21 includes a plurality of first microlenses 211 arranged in an array. The orthographic projection of each first microlens 211 on the photosensitive unit 23 covers at least a part of at least one photosensitive unit 23. For example, the orthographic projection of each first microlens 211 on the photosensitive unit 23 covers at least the photosensitive area of at least one photosensitive unit 23.

[0045] The second microlens layer 22 is disposed on the side of the first microlens layer 21 facing away from the photosensitive unit 23 and includes a plurality of second microlenses 221 arranged in an array. The orthographic projection of each second microlens 221 on the photosensitive unit 23 covers at least a part of at least two first microlenses 211. For example, the orthographic projection of each microlens 1311 on the photosensitive unit 23 covers at least the photosensitive areas of the photosensitive units 23 corresponding to at least two first microlenses 211. In the present application, for the convenience of description, the first microlens 211 is corresponded to the photosensitive unit 23 covered by the first microlens 211, and the second microlens 221 is corresponded to the photosensitive unit 23 covered by the second microlens 221.

[0046] Moreover, the refractive index of the material of the second microlens layer 22 is less than the refractive index of the material of the first microlens layer 21. For example, the refractive index of the material of the second microlens layer 22 is between the refractive index of air and the refractive index of the material of the first microlens layer 21.

[0047] Combined Figure 5As shown, in the above image sensor 20, a stacked first microlens layer 21 and second microlens layer 22 are provided on the light incident side of the photosensitive unit 23, and the refractive index of the material of the second microlens layer 22 is less than that of the material of the first microlens layer 21. Light from the lens 131 can be refracted by the second microlens layer 22 and the first microlens layer 21 in sequence and then reach the photosensitive unit 23.

[0048] Thus, the second microlens layer 22 can play a role in refractive index transition between the first microlens layer 21 and the air medium, reducing the refractive index difference that the light passes through when incident (for example, the refractive index difference between air and the second microlens 221, and the refractive index difference between the second microlens 221 and the first microlens 211 is less than the refractive index difference between air and the first microlens 211), which is beneficial to suppressing the reflection and scattering phenomena of light on the light incident surfaces of the first microlens 211 and the second microlens 221.

[0049] At the same time, the gradual transition of the refractive index is beneficial to slowing down the deflection angle of light on the respective surfaces of the first microlens 211 and the second microlens 221 (the light incident surface and the light exit surface of the second microlens 221, and the light incident surface and the light exit surface of the first microlens 211), which is beneficial to suppressing the generation of aberrations such as distortion and improving the imaging quality and photosensitive performance of the image sensor 20. The two converging effects of the first microlens 211 and the second microlens 221 can also improve the degree of light convergence and the utilization efficiency of the photosensitive unit 23 for light.

[0050] In addition, guiding light to the photosensitive unit 23 through the first microlenses 211 with a large arrangement density is beneficial to reducing the signal crosstalk between adjacent photosensitive units 23 and is beneficial to improving the resolution of the image sensor 20, while the second microlenses 221 with a small arrangement density and a large size are beneficial to collecting more light and suppressing the scattering and diffraction phenomena of light, which is beneficial to improving the quantum efficiency and focusing performance of the image sensor 20. Through the combination of the first microlens layer 21 and the second microlens layer 22, it is possible to well balance the improvement of resolution, quantum efficiency and focusing performance.

[0051] The size of a single pixel (i.e., the diagonal length of the photosensitive unit 23) in the image sensor 20 provided in this application can be less than or equal to 2um. For example, the diagonal length of a single photosensitive unit 23 can be 0.56um, 0.61um or 0.7um, etc. By adopting the above image sensor 20, in the image sensor 20 where the diagonal length of the photosensitive unit 23 is less than or equal to 2um, it is also possible to well balance the improvement of resolution, quantum efficiency and focusing performance.

[0052] In this application, for the convenience of description, according to the incident and outgoing relationships of light, the surface of the second microlens 221 facing away from the photosensitive unit 23 is referred to as the incident light surface of the second microlens 221, and the surface of the second microlens 221 facing the photosensitive unit 23 is referred to as the outgoing light surface of the second microlens 221. The surface of the first microlens 211 facing away from the photosensitive unit 23 is referred to as the incident light surface of the first microlens 211, and the surface of the first microlens 211 facing the photosensitive unit 23 is referred to as the outgoing light surface of the first microlens 211.

[0053] In this application, the photosensitive unit 23 includes, but is not limited to, adopting a front-illuminated (FSI) or back-illuminated (BSI) design. When the photosensitive unit 23 adopts a front-illuminated design, in the direction from the second microlens layer 22 to the first microlens layer 21, the photosensitive unit 23 includes a color filter layer 231, a conductive interconnection layer, and a photoelectric conversion layer that are sequentially stacked. When the photosensitive unit 23 adopts a back-illuminated design, in the direction from the second microlens layer 22 to the first microlens layer 21, the photosensitive unit 23 includes a color filter layer 231, a photoelectric conversion layer, and a conductive interconnection layer that are sequentially stacked. The color filter layer 231 is used to filter the light incident on the photosensitive unit 23, for example, only allowing light of one of the red, green, and blue colors to pass through. The conductive interconnection layer is used to transmit the electrical signals of the image sensor 20, and the photoelectric conversion layer is used to convert the optical signal into an electrical signal. The photoelectric conversion layer includes any suitable photoelectric conversion device such as a photodiode. Of course, the structural arrangement of the photosensitive unit 23 is not limited to the description in the embodiments of this application, as long as the functional group can achieve the conversion of optical and electrical signals.

[0054] In this application, the surface of the photosensitive unit 23 closest to the first microlens 211 is referred to as the incident light surface of the photosensitive unit 23. For example, when the color filter layer 231 is the structure in the photosensitive unit 23 closest to the first microlens layer 21, the surface of the color filter layer 231 facing the first microlens layer 21 is referred to as the incident light surface of the photosensitive unit 23.

[0055] Reference Figure 5 As shown, in some embodiments, the incident light surface of the first microlens 211 is a convex surface, the outgoing light surface is a flat surface, the incident light surface of the second microlens 221 is a convex surface, and the outgoing light surface is attached to and covers the corresponding incident light surface of the first microlens 211. The outgoing light surface of the first microlens 211 can be a flat surface attached to the incident light surface of the photosensitive unit 23. In this way, while enabling the first microlens 211 and the second microlens 221 to have light-gathering capabilities, the first microlens layer 21 can be directly formed on the photosensitive structure layer, only the surface shape of the incident light surface of the first microlens 211 needs to be controlled, and the second microlens layer 22 can be directly formed on the first microlens layer 21, only the surface shape of the incident light surface of the second microlens 221 needs to be controlled, which is beneficial to reducing the manufacturing difficulty and manufacturing cost of the first microlens layer 21 and the second microlens layer 22.

[0056] In some embodiments, the difference in refractive index between the materials of the first microlens layer 21 and the second microlens layer 22 is greater than or equal to 0.1. For example, the difference in refractive index between the materials of the first microlens layer 21 and the second microlens layer 22 can be 0.1, 0.2, or 0.3, etc. In this way, there can be a sufficient refractive index difference between the second microlens 221 and the first microlens 211 to play an effective refractive index transition role between the air medium and the first microlens 211, which is conducive to suppressing the generation of phenomena such as reflection and scattering.

[0057] The specific settings of the refractive indices of the materials of the first microlens layer 21 and the second microlens layer 22 are not limited, as long as the above-mentioned refractive index difference of the materials can be satisfied. In some embodiments, the refractive indices of the materials of the first microlens layer 21 and the second microlens layer 22 are both greater than or equal to 1.1 and less than or equal to 2. For example, the refractive index of the material of the first microlens layer 21 can be 1.52, and the refractive index of the material of the second microlens layer 22 can be 1.64. Or, the refractive index of the material of the first microlens layer 21 can be 1.49, and the refractive index of the material of the second microlens layer 22 can be 1.59, etc.

[0058] The materials of the first microlens layer 21 and the second microlens layer 22 include, but are not limited to, any materials such as glass and resin.

[0059] Reference Figure 6 and Figure 7 As shown, in some embodiments, the image sensor 20 further includes a first transition layer 24. The first transition layer 24 is disposed between the photosensitive unit 23 and the first microlens layer 21. Both opposite sides of the first transition layer 24 are flat and are respectively attached to the photosensitive unit 23 and the first microlens layer 21. The material of the first transition layer 24 can be the same as the material of the first microlens layer 21. The first transition layer 24 can be formed on the photosensitive unit 23 by the same process as the first microlens layer 21, so the first transition layer 24 and the first microlens layer 21 can be an integral structure.

[0060] Providing the first transition layer 24 is beneficial to smoothing the light conduction path between the first microlens layer 21 and the photosensitive unit 23, reducing the reflection and refraction distortion of light on each surface. At the same time, it is beneficial to adjust the distance between the light incident surface of the first microlens 211 and the photosensitive unit 23, adjust the converging effect of the light passing through the first microlens 211 on the photosensitive unit 23, and improve the light collection efficiency. Providing a flat first transition layer 24 is also beneficial to improving the stacking accuracy of the first microlens layer 21 on the photosensitive unit 23. In addition, it is beneficial to improve the thermal stability of the image sensor 20, reduce the stress risk, and improve the mechanical stability and durability of the structure.

[0061] In some embodiments, the image sensor 20 further includes a second transition layer 25 disposed between the first microlens layer 21 and the second microlens layer 22. Both opposite sides of the second transition layer 25 are flat surfaces and are respectively adhered to the first microlens layer 21 and the second microlens layer 22. The material of the second transition layer 25 may be the same as that of the second microlens layer 22, and the second transition layer 25 and the second microlens layer 22 may be formed on the photosensitive unit 23 by the same process.

[0062] The provision of the second transition layer 25 is conducive to smoothing the light conduction path between the second microlens layer 22 and the first microlens layer 21, reducing the reflection and refraction distortion of light on each surface, and at the same time is conducive to adjusting the distance between the light incident surface of the second microlens 221 and the photosensitive unit 23, adjusting the converging effect of the light passing through the second microlens 221 on the photosensitive unit 23, and improving the light collection efficiency. Providing the flat second transition layer 25 is also conducive to improving the stacking accuracy of the second microlens layer 22 on the first microlens layer 21. In addition, it is also conducive to improving the thermal stability of the image sensor 20, reducing the stress risk, and improving the mechanical stability and durability of the structure. Either the first transition layer 24 or the second transition layer 25 can be provided alone, or both can be provided simultaneously.

[0063] In some embodiments, when the image sensor 20 is provided with the first transition layer 24, the thickness of the first transition layer 24 is less than or equal to the sum of the thickness of the first microlens layer 21 and the diagonal length of the photosensitive unit 23. When the image sensor 20 is provided with the second transition layer 25, the thickness of the second transition layer 25 is less than or equal to the sum of the thickness of the second microlens layer 22 and the diagonal length of the photosensitive unit 23. Thus, it is possible to avoid the excessive increase in the occupied space of the image sensor 20 due to the provision of the first transition layer 24 and the second transition layer 25, and at the same time, it is also possible to avoid the light being difficult to effectively converge on the photoelectric conversion layer of the photosensitive unit 23 due to the excessive distance between the first microlens layer 21 and the second microlens layer 22 from the photosensitive unit 23.

[0064] In the present application, the diagonal length of the photosensitive unit 23 can be understood as the diagonal length of the photosensitive area of the photosensitive unit 23.

[0065] Reference Figure 8As shown, in some embodiments, the orthographic projection of each first microlens 211 on the photosensitive unit 23 covers the photosensitive areas of a plurality of photosensitive units 23, and the number of the plurality of photosensitive units 23 covered by one first microlens 211 is equal in the first direction 26 and the second direction 27. The first direction 26 and the second direction 27 are two mutually perpendicular directions on a plane parallel to the light incident surface of the photosensitive unit 23. With such a setting, through the symmetric covering design of the first microlens 211, color deviation and optical distortion caused by the change of the light incident angle can be reduced. At the same time, it is beneficial to avoid the optical path offset caused by thermal expansion and contraction, which is beneficial to improving the stability of the photosensitive performance of the image sensor 20.

[0066] In some embodiments, the orthographic projection of each second microlens 221 on the photosensitive unit 23 covers a plurality of first microlenses 211 and covers the photosensitive areas of the photosensitive units 23 corresponding to the corresponding plurality of first microlenses 211, and the number of the plurality of first microlenses 211 covered by one second microlens 221 is equal in the first direction 26 and the second direction 27. With such a setting, through the symmetric covering design of the second microlens 221, color deviation and optical distortion caused by the change of the light incident angle can be reduced. At the same time, it is beneficial to avoid the optical path offset caused by thermal expansion and contraction, which is beneficial to improving the stability of the photosensitive performance of the image sensor 20.

[0067] Reference Figure 9 As shown, in some other embodiments, the number of the plurality of first microlenses 211 covered by one second microlens 221 in the first direction 26 is greater than the number in the second direction 27. The flexible setting of the corresponding number of the second microlens 221 and the first microlens 211 can improve the flexibility of the manufacturing process of the second microlens layer 22, and at the same time can meet the requirements of different usage scenarios and photosensitive performance.

[0068] For example, when a higher requirement is imposed on the image resolution of the image sensor 20, the number of the photosensitive units 23 covered by each first microlens 211 can be appropriately reduced to reduce the optical signal crosstalk and improve the image resolution. When a higher requirement is imposed on the quantum efficiency and focusing performance of the image sensor 20, the number of the first microlenses 211 covered by each second microlens 221 can be appropriately increased.

[0069] The following provides some embodiments of the corresponding relationships among the numbers of the second microlenses 221, the first microlenses 211, and the photosensitive units 23 as examples. The corresponding relationships among the numbers of the second microlenses 221, the first microlenses 211, and the photosensitive units 23 are not limited to the descriptions of the embodiments of the present application.

[0070] Combined with Figure 5 and Figure 8As shown, in some embodiments, the orthographic projection of each first microlens 211 on the photosensitive unit 23 covers the light incident surface of the corresponding photosensitive unit 23. The orthographic projection of each second microlens 221 on the photosensitive unit 23 covers the corresponding four first microlenses 211, and the four first microlenses 211 covered by one second microlens 221 are arranged in a two-row and two-column array. With such an arrangement, by reasonably designing the arrangement density of the first microlenses 211 and the second microlenses 221, the image resolution, quantum efficiency, and focusing performance of the image sensor 20 can be effectively balanced, and the photosensitive performance of the image sensor 20 can be improved.

[0071] Reference Figure 9 As shown, in some embodiments, the orthographic projection of each first microlens 211 on the photosensitive unit 23 covers the light incident surface of the corresponding photosensitive unit 23, and the orthographic projection of each second microlens 221 on the photosensitive unit 23 covers the corresponding two first microlenses 211. In this embodiment, the two photosensitive units 23 covered by one second microlens 221 are arranged in sequence in the first direction 26, so the size of the second microlens 221 in the first direction 26 is larger than the size in the second direction 27.

[0072] Reference Figure 10 As shown, in some embodiments, the orthographic projection of each first microlens 211 on the photosensitive unit 23 covers the light incident surfaces of the corresponding four photosensitive units 23, and the four photosensitive units 23 covered by one first microlens 211 are arranged in a two-row and two-column array. The orthographic projection of each second microlens 221 on the photosensitive unit 23 covers four first microlenses 211, and the four first microlenses 211 covered by one second microlens 221 are arranged in a two-row and two-column array. That is to say, the orthographic projection of each second microlens 221 on the photosensitive unit 23 covers the light incident surfaces of sixteen photosensitive units 23, and the sixteen photosensitive units 23 covered by one second microlens 221 are arranged in a four-row and four-column array. With such an arrangement, the manufacturing difficulty and cost of the first microlens layer 21 and the second microlens layer 22 can be reduced, and at the same time, it is beneficial to improve the light collection efficiency, the quantum efficiency, and the focusing performance of the image sensor 20.

[0073] In some embodiments, an antireflection film layer is provided on at least one of the light incident surface of the first microlens layer 21 and the light incident surface of the second microlens layer 22. The provision of the antireflection film layer can reduce the reflection and scattering effects when light hits the light incident surface of the first microlens 211 and / or the light incident surface of the second microlens 221, and improve the light collection efficiency.

[0074] Reference Figure 11As shown, in some embodiments, the edge contour of a part of the second microlens 221 in the image sensor 20 is misaligned with the edge contour of the corresponding first microlens 211. Among them, the edge contour of the second microlens 221 on the photosensitive unit 23 in the central region of the image sensor 20 can coincide with the edge contour of the corresponding first microlens 211 and the edge contour of the corresponding photosensitive unit 23. In the direction from the center to the edge of the image sensor 20, the relative offset between the edge contours of at least some of the second microlenses 221 and the corresponding first microlenses 211 gradually increases. That is to say, for the field-of-view region with a larger corresponding field-of-view angle, the relative offset between the edge contour of the second microlens 221 and the edge contour of the corresponding first microlens 211 can also be larger.

[0075] When the edge contour of the second microlens 221 is misaligned with the edge contour of the corresponding first microlens 211, the edge contour of the second microlens 221 can be offset relative to the edge contour of the corresponding first microlens 211 toward the side where the center of the image sensor 20 is located.

[0076] With such a setting, the relative positional relationship between the second microlens 221 and the first microlens 211 can adapt to the different incident angles of light in different fields of view, so as to better collect the light in different fields of view, improve the light collection and utilization efficiency, and suppress phenomena such as reflection and scattering.

[0077] Reference Figure 12 As shown, when the edge contour of the second microlens 221 is misaligned with the edge contour of the corresponding first microlens 211, the edge contour of the first microlens 211 can also be misaligned with the contour of the corresponding photosensitive unit 23. For example, the edge contour of the first microlens 211 is offset relative to the edge contour of the photosensitive unit 23 toward the side where the center of the image sensor 20 is located. With such a setting, through the two offset settings of the first microlens 211 and the second microlens 221, the adaptability to the incident angles of light in different fields of view can be further improved, the light collection and utilization efficiency can be further improved, and phenomena such as reflection and scattering can be suppressed.

[0078] Of course, the offset of the edge contour of the second microlens 221 relative to the edge contour of the light incident surface of the photosensitive unit 23, the offset of the edge contour of the second microlens 221 relative to the edge contour of the first microlens 211, and the offset of the edge contour of the first microlens 211 relative to the edge contour of the light incident surface of the photosensitive unit 23 should be less than the diagonal length of a photosensitive unit 23, so as to prevent the offset of the second microlens 221 and the first microlens 211 from affecting the light reception of the photosensitive unit 23.

[0079] It should be noted that the double-layer microlens structure composed of the first microlens layer 21 and the second microlens layer 22 provided in this application can be used not only in the image sensor 20 described in the embodiments of this application, but also in display panels such as micro-OLED or micro-LED of the electronic device 10. The light-emitting layer of the display panel may include a plurality of light-emitting units arranged in an array. The first microlens layer 21 is disposed on the light-emitting side of the light-emitting layer, and the second microlens layer 22 is disposed on the side of the first microlens layer 21 facing away from the light-emitting layer. The first microlens layer 21 and the second microlens layer 22 may be sequentially stacked on the color film layer or any other applicable film layer structure of the display panel.

[0080] By adopting the above double-layer microlens structure in the display panel, the light emitted by the light-emitting units can be collimated after passing through the first microlens 211 and the second microlens 221 in sequence and then emitted from the display panel. Through two times of collimation and the matching design of the refractive index, it is beneficial to improve the light extraction efficiency of the display panel, and phenomena such as scattering, diffraction, and reflection are reduced in sequence, thereby improving the light-emitting brightness of the display panel. At the same time, the setting of the first microlenses 211 with a higher arrangement density is also beneficial to improving the image resolution of the display panel, thus effectively taking into account the improvement of both the image resolution and the light-emitting brightness of the display panel.

[0081] The above settings of the double-layer microlens structure in the image sensor 20 are all applicable to the display panel and will not be elaborated in this application.

[0082] Reference Figure 13 , Figure 13 is a schematic structural diagram of the electronic device 10 provided in the embodiments of this application. The electronic device 10 may include a radio frequency (RF) circuit 501, a memory 502 including one or more computer-readable storage media, an input unit 503, a display unit 504, a sensor 505, an audio circuit 506, a wireless fidelity (WiFi) module 507, a processor 508 including one or more processing cores, and a power supply 509, etc. Those skilled in the art can understand that Figure 13 the structure of the electronic device 10 shown in

[0083] The radio frequency circuit 501 can be used to receive and transmit information, or receive and send signals during a call. In particular, after receiving the downlink information of the base station, it is handed over to one or more processors 508 for processing. Additionally, data related to the uplink is sent to the base station. Generally, the radio frequency circuit 501 includes, but is not limited to, an antenna, at least one amplifier, a tuner, one or more oscillators, a subscriber identity module (SIM) card, a transceiver, a coupler, a low noise amplifier (LNA), a duplexer, etc. In addition, the radio frequency circuit 501 can also communicate with the network and other devices through wireless communication. This wireless communication can use any communication standard or protocol, including but not limited to the Global System of Mobile communication (GSM), General Packet Radio Service (GPRS), Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (WCDMA), Long Term Evolution (LTE), email, Short Messaging Service (SMS), etc.

[0084] The memory 502 can be used to store application programs and data. The application programs stored in the memory 502 contain executable code. The application programs can form various functional modules. The processor 508 executes various functional applications and data processing by running the application programs stored in the memory 502. The memory 502 mainly includes a program storage area and a data storage area. Among them, the program storage area can store an operating system, application programs required for at least one function (such as a sound playback function, an image playback function, etc.); the data storage area can store data created according to the use of the electronic device 10 (such as audio data, a phone book, etc.). In addition, the memory 502 can include high-speed random access memory, and can also include non-volatile memory, such as at least one magnetic disk storage device, a flash memory device, or other non-volatile solid-state storage devices. Correspondingly, the memory 502 can also include a memory controller to provide access to the memory 502 for the processor 508 and the input unit 503.

[0085] The input unit 503 can be used to receive input numerical, character information or user characteristic information (such as fingerprints), and generate keyboard, mouse, joystick, optical or trackball signal inputs related to user settings and function control. Specifically, in a specific embodiment, the input unit 503 may include a touch-sensitive surface and other input devices. The touch-sensitive surface, also known as a touch display screen or a touchpad, can collect touch operations of the user on or near it (such as operations of the user using any suitable object or accessory such as a finger or a stylus on or near the touch-sensitive surface), and drive the corresponding connection device according to a preset program. Optionally, the touch-sensitive surface may include two parts: a touch detection device and a touch controller. Among them, the touch detection device detects the touch position of the user and detects the signal brought by the touch operation, and transmits the signal to the touch controller; the touch controller receives the touch information from the touch detection device, converts it into contact coordinates, and then sends it to the processor 508, and can receive and execute the commands sent by the processor 508.

[0086] The display unit 504 can be used to display information input by the user or information provided to the user, as well as various graphical user interfaces of the electronic device 10. These graphical user interfaces can be composed of graphics, text, icons, videos and any combination thereof. The display unit 504 may include a display panel. Optionally, the display panel can be configured in the form of a liquid crystal display (LCD), an organic light-emitting diode (OLED), etc. Further, the touch-sensitive surface can cover the display panel. After the touch-sensitive surface detects a touch operation on or near it, it is transmitted to the processor 508 to determine the type of touch event. Subsequently, the processor 508 provides a corresponding visual output on the display panel according to the type of touch event. Although in Figure 13 the touch-sensitive surface and the display panel are implemented as two independent components to achieve input and input functions, in some embodiments, the touch-sensitive surface and the display panel can be integrated to achieve input and output functions.

[0087] The electronic device 10 may further include at least one sensor 505, such as a light sensor, a motion sensor, and other sensors. Specifically, the light sensor may include an ambient light sensor and a proximity sensor. Among them, the ambient light sensor can adjust the brightness of the display panel according to the brightness of the ambient light, and the proximity sensor can turn off the display panel and / or the backlight when the electronic device 10 is moved to the ear. As a kind of motion sensor, the gravity acceleration sensor can detect the magnitude of acceleration in all directions (generally three axes). When stationary, it can detect the magnitude and direction of gravity, and can be used for applications that identify the posture of the mobile phone (such as horizontal and vertical screen switching, related games, magnetometer posture calibration), vibration recognition related functions (such as pedometer, tapping), etc. As for other sensors such as a gyroscope, a barometer, a hygrometer, a thermometer, and an infrared sensor that the electronic device 10 may also be configured with, they will not be elaborated here.

[0088] The audio circuit 506 can provide an audio interface between the user and the electronic device 10 through a speaker and a microphone. The audio circuit 506 can convert the received audio data into an electrical signal and transmit it to the speaker, which converts it into a sound signal for output. On the other hand, the microphone converts the collected sound signal into an electrical signal, which is received by the audio circuit 506 and then converted into audio data. After the audio data is output to the processor 508 for processing, it is sent through the radio frequency circuit 501 to, for example, another electronic device 10, or the audio data is output to the memory 502 for further processing. The audio circuit 506 may also include a headphone jack to provide communication between the peripheral headphone and the electronic device 10.

[0089] Wireless Fidelity (WiFi) belongs to short - range wireless transmission technology. The electronic device 10 can help users send and receive emails, browse the web, and access streaming media through the WiFi module 507, which provides users with wireless broadband Internet access. Although Figure 13 the WiFi module 507 is shown, it can be understood that it does not belong to the essential components of the electronic device 10 and can be completely omitted within the scope of not changing the essence of the invention according to needs.

[0090] The processor 508 is the control center of the electronic device 10, connecting various parts of the entire electronic device 10 using various interfaces and lines. By running or executing the application programs stored in the memory 502 and calling the data stored in the memory 502, it executes various functions of the electronic device 10 and processes data, thereby monitoring the electronic device 10 as a whole. Optionally, the processor 508 may include one or more processing cores; preferably, the processor 508 may integrate an application processor and a modem processor. Among them, the application processor mainly processes the operating system, user interface, and application programs, and the modem processor mainly processes wireless communication. It can be understood that the above - mentioned modem processor may not be integrated into the processor 508 either.

[0091] The electronic device 10 further includes a power source 509 for supplying power to each component. Preferably, the power source 509 can be logically connected to the processor 508 through a power management system, so as to implement functions such as management of charging, discharging, and power consumption management through the power management system. The power source 509 can also include any components such as one or more DC or AC power sources, a recharge system, a power failure detection circuit, a power converter or inverter, and a power status indicator.

[0092] Although Figure 13 not shown in the figure, the electronic device 10 may further include a Bluetooth module, etc., which will not be elaborated here. In specific implementation, each of the above modules can be implemented as an independent entity, or can be combined arbitrarily and implemented as the same or several entities. For the specific implementation of each of the above modules, reference can be made to the foregoing method embodiments, which will not be elaborated here.

[0093] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0094] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An image sensor, characterized in that, Comprising: A plurality of photosensitive units arranged in an array; A first microlens layer, disposed on the light incident side of the photosensitive units, and including a plurality of first microlenses arranged in an array, the positive projection of each first microlens on the photosensitive unit covering at least a part of at least one of the photosensitive units; And, A second microlens layer, disposed on the side of the first microlens layer facing away from the photosensitive units, and including a plurality of second microlenses arranged in an array, the positive projection of each second microlens on the photosensitive unit covering at least a part of at least two of the first microlenses, and the refractive index of the material of the second microlens layer being less than the refractive index of the material of the first microlens layer.

2. The image sensor according to claim 1, wherein The light incident surface of the first microlens is convex, and the light exiting surface is flat. The light incident surface of the second microlens is convex, and the light exiting surface is attached to and covers the light incident surface of the corresponding first microlens.

3. The image sensor according to claim 1, wherein The difference between the refractive indices of the material of the first microlens layer and the second microlens layer is greater than or equal to 0.

1.

4. The image sensor according to claim 3, wherein The refractive indices of both the first microlens layer and the second microlens layer are greater than or equal to 1.1 and less than or equal to 2.

5. The image sensor according to claim 1, wherein The image sensor further includes a first transition layer, the first transition layer being disposed between the photosensitive units and the first microlens layer, both opposite sides of the first transition layer being flat and being respectively attached to the photosensitive units and the first microlens layer; and / or, The image sensor further includes a second transition layer, the second transition layer being disposed between the first microlens layer and the second microlens layer, both opposite sides of the second transition layer being flat and being respectively attached to the first microlens layer and the second microlens layer.

6. The image sensor according to claim 5, wherein When the image sensor includes the first transition layer, the thickness of the first transition layer is less than or equal to the sum of the thickness of the first microlens layer and the diagonal length of the photosensitive unit; When the image sensor includes the second transition layer, the thickness of the second transition layer is less than or equal to the sum of the thickness of the second microlens layer and the diagonal length of the photosensitive unit.

7. The image sensor according to claim 1, characterized in that, The positive projection of each first microlens on the photosensitive unit covers a plurality of the photosensitive units, and the number of the photosensitive units covered by one first microlens is equal in a first direction and a second direction perpendicular to each other; The positive projection of each second microlens on the photosensitive unit covers a plurality of the first microlenses, and the number of the first microlenses covered by one second microlens is equal in the first direction and the second direction, or the number of the first microlenses covered by one second microlens in the first direction is greater than the number in the second direction.

8. The image sensor according to claim 1, characterized in that, The positive projection of each first microlens on the photosensitive unit covers the light incident surface of a corresponding one of the photosensitive units. The positive projection of each second microlens on the photosensitive unit covers four corresponding first microlenses, and the four first microlenses covered by one second microlens are arranged in a two-row and two-column array; or, The orthographic projection of each of the first microlenses on the photosensitive unit covers the light incident surface of a corresponding photosensitive unit, and the orthographic projection of each of the second microlenses on the photosensitive unit covers two corresponding first microlenses; or, The orthographic projection of each of the first microlenses on the photosensitive unit covers the light incident surfaces of four corresponding photosensitive units, and the four photosensitive units covered by one first microlens are arranged in a two-row and two-column array. The orthographic projection of each of the second microlenses on the photosensitive unit covers four first microlenses, and the four first microlenses covered by one second microlens are arranged in a two-row and two-column array.

9. The image sensor according to claim 1, wherein The edge contours of some of the second microlenses are misaligned with the edge contours of the corresponding first microlenses, and in the direction from the center to the edge of the image sensor, the relative offset amount of the edge contours of at least some of the second microlenses and the edge contours of the corresponding first microlenses gradually increases.

10. The image sensor according to claim 1, wherein, The image sensor further includes an anti-reflection film layer provided on the light incident surface of the first microlens layer; and / or, the image sensor further includes an anti-reflection film layer provided on the light incident surface of the second microlens layer.

11. The image sensor according to claim 1, characterized in that, The diagonal length of the photosensitive unit is less than or equal to 2 μm.

12. A camera module, characterized in that, It includes the image sensor according to any one of claims 1-11.

13. An electronic device, characterized in that, It includes the imaging module according to claim 12.

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