Microlens structure, method for manufacturing microlens structure, and electronic device

Abstract

The application provides a microlens structure, a preparation method of the microlens structure and an electronic device. The microlens structure comprises a substrate layer, a first microlens and a second microlens. The substrate layer comprises a substrate layer body and a plurality of substrate pedestals. The substrate pedestals are fixed on the substrate layer body and located in a second region. The substrate pedestals comprise a bottom surface and an inclined surface with a preset inclination angle relative to the bottom surface. The distance between the inclined surface and the corresponding bottom surface gradually decreases in a direction away from the first region. The first microlens is located on the substrate layer body, and the second microlens is located on the inclined surface of the corresponding substrate pedestal. In the direction away from the first region, the inclination angle between the inclined surface and the bottom surface of the substrate pedestal gradually increases. The above structure sets the microlens with the inclination angle, and the inclination angle gradually increases in the direction away from the first region, so that each microlens can effectively match the exit light angle or the incident light angle at the corresponding position, thereby improving the light output efficiency or the light collection efficiency at the position.

Description

Technical Field

[0001] This application relates to the field of microlens technology, and more specifically, to a microlens structure, a method for fabricating the microlens structure, and an electronic device thereof. Background Technology

[0002] Microlens arrays (MLAs) are key components in modern optical imaging and display systems, widely used in CMOS image sensors, augmented reality (AR), and virtual reality (VR). In CMOS image sensors, MLAs are used to focus incident light onto the photosensitive area of ​​a photodiode, thereby improving quantum efficiency and signal-to-noise ratio. In AR / VR display systems, MLAs are used to improve pixel light extraction efficiency, achieving high resolution and a wide field of view. However, all of these electronic devices face the optical mismatch problem of edge microlenses. For CMOS image sensors, microlenses located at the edges cannot effectively focus incident light onto the photodiode (i.e., the photodiode) due to a significant deviation in the principal ray angle of the incident light compared to the central region. This results in decreased light collection efficiency, exacerbated shadowing effects, and severely impacts the uniformity of image quality. For AR / VR display systems, microlenses located at the edge have their optical axes perpendicular to the surface of optoelectronic devices (i.e., light-emitting devices), making it difficult for the emitted light to deflect towards a large field of view. In other words, they cannot match the required angle of emitted light at the edge, which restricts the display effect and light emission efficiency of the display system in large field-of-view scenarios.

[0003] Therefore, how to effectively improve the matching ability of microlens arrays to the outgoing light angle or the incoming light angle at corresponding positions, so as to improve the light extraction efficiency or light collection efficiency of electronic devices, has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] To overcome the technical problems mentioned in the above background, this application provides a microlens structure, the microlens structure comprising: A substrate layer having a first region and a second region surrounding the first region, the substrate layer including a substrate layer body and a plurality of substrate bases, the substrate bases being fixed to the substrate layer body and located in the second region, the substrate bases including a bottom surface and an inclined surface having a preset tilt angle with the bottom surface, the distance between the inclined surface and the corresponding bottom surface gradually decreasing in the direction away from the first region in a direction perpendicular to the surface of the substrate layer body; A first microlens is located on the substrate layer body in the first region; The second microlens is located on the inclined surface of the substrate base in the second region; Along the surface of the substrate layer body and away from the first region, the angle of inclination between the inclined surface of the substrate base and the bottom surface gradually increases.

[0005] In one possible implementation, the substrate bases that are at the same distance from the first region have the same tilt angle; Multiple substrate bases are arranged at intervals along a direction away from the first region, and the spacing between adjacent substrate bases is the same.

[0006] In one possible implementation, the first angle formed between the optical axis of the second microlens and the direction perpendicular to the bottom surface of the corresponding substrate base is the same as the tilt angle of the substrate base. The first microlens is of the same type as the second microlens, and the first microlens can be a spherical lens, an aspherical lens, or a freeform surface lens. The radius of curvature of the first microlens is the same as that of the second microlens, and the radius of curvature of the first microlens is 1 micrometer to 50 micrometers.

[0007] In one possible implementation, the refractive index of the second microlens is greater than the refractive index of the substrate layer; The refractive index of the first microlens is the same as that of the second microlens, and the refractive index of the second microlens is 1.4~2.2; The first microlens is made of the same material as the second microlens, and the material of the first microlens includes a transparent polymer material, a glass material, or a dielectric material.

[0008] This application also provides a method for fabricating a microlens structure, the method comprising: Provide a substrate material layer; A mask material layer is formed on one side of the substrate material layer; The mask material layer is patterned to obtain a patterned mask material layer; The substrate material layer is etched based on the patterned mask material layer to form a substrate layer. The substrate layer has a first region and a second region surrounding the first region. The substrate layer includes a substrate layer body and a plurality of substrate bases. The substrate bases are fixed on the substrate layer body and located in the second region. The substrate base includes a bottom surface and an inclined surface with a preset tilt angle to the bottom surface. In a direction perpendicular to the surface of the substrate layer body, the distance between the inclined surface and the corresponding bottom surface gradually decreases in the direction away from the first region. A first microlens is fabricated on the substrate layer body in the first region, and a second microlens is fabricated on the inclined surface corresponding to the substrate base in the second region, thereby forming the microlens structure.

[0009] In one possible implementation, prior to the step of providing a substrate material layer, the method further includes: The tilt angle of the second microlens at the target position on the substrate layer is predetermined; An imprinting substrate is fabricated based on the position of the second microlens on the substrate layer and the tilt angle corresponding to the second microlens, wherein the imprinting substrate includes an imprinting groove corresponding to the tilt angle of the second microlens. The step of patterning the mask material layer to obtain a patterned mask material layer includes: The side of the imprinting substrate with the imprinting groove is imprinted towards the mask material layer, and an imprinting base is formed on the side of the mask material layer away from the substrate material layer to obtain the patterned mask material layer. The step of etching the substrate material layer based on the patterned mask material layer to form the substrate layer includes: Based on the patterned mask material layer, the substrate material layer is etched to transfer the pattern of the imprinted base on the mask material layer onto the substrate material layer, thus obtaining the substrate layer.

[0010] In one possible implementation, the step of fabricating a first microlens on the substrate layer body in the first region and fabricating a second microlens on the inclined surface corresponding to the substrate base in the second region to form the microlens structure includes: A microlens material layer covering the substrate layer is formed on the substrate layer; Multiple blocking units for forming the first microlens and the second microlens are fabricated on the side of the microlens material layer away from the substrate layer; Based on the blocking unit, the microlens material layer is etched to transfer the pattern of the blocking unit to the microlens material layer, forming the first microlens on the substrate layer body located in the first region and the second microlens on the inclined surface of the corresponding substrate base located in the second region, thus obtaining the microlens structure.

[0011] This application also provides an electronic device, which includes a substrate and the microlens structures provided in the aforementioned embodiments of this application, wherein the microlens structures are disposed on one side of the substrate; The substrate includes an optoelectronic device layer, which includes multiple optoelectronic devices. The second angle formed by the optical axis of the second microlens of the microlens structure corresponding to the optoelectronic device and the direction perpendicular to the plane where the optoelectronic device is located is the same as the tilt angle of the substrate base of the microlens structure corresponding to the optoelectronic device.

[0012] In one possible implementation, the substrate further includes a substrate and a photoelectric conversion layer located on the substrate; The optoelectronic device layer is located on the side of the optoelectronic conversion layer away from the substrate; The photoelectric conversion layer is used to convert the optical signal received by the photoelectric device in the photoelectric device layer into an electrical signal, or to drive the photoelectric device in the photoelectric device layer to emit light. The optoelectronic device includes a photosensitive device or a light-emitting device.

[0013] In one possible implementation, the orthographic projection of the substrate base onto the substrate covers the orthographic projection of the corresponding optoelectronic device onto the substrate; The orthogonal projection of the first microlens onto the substrate covers the orthogonal projection of the optoelectronic device corresponding to the first microlens onto the substrate, and the orthogonal projection of the second microlens onto the substrate covers the orthogonal projection of the optoelectronic device corresponding to the second microlens onto the substrate.

[0014] Based on any of the above aspects, embodiments of this application provide a microlens structure, a method for fabricating the microlens structure, and an electronic device. The microlens structure includes a substrate layer, a first microlens, and a second microlens. The substrate layer includes a substrate layer body and multiple substrate bases. The substrate bases are fixed on the substrate layer body and located in a second region. Each substrate base includes a bottom surface and an inclined surface with a preset tilt angle to the bottom surface. The distance between the inclined surface and the corresponding bottom surface gradually decreases in the direction away from the first region. The first microlens is located on the substrate layer body, and the second microlens is located on the inclined surface of the corresponding substrate base. In the direction away from the first region, the tilt angle between the inclined surface of the substrate base and the bottom surface gradually increases. By providing microlenses with tilt angles that gradually increase in the direction away from the first region, the above structure enables each microlens to effectively match the emitted light angle or incident light angle at its corresponding position, thereby improving the light emission efficiency or light collection efficiency at that position. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings required in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of a microlens structure provided in this embodiment; Figure 2 This is a schematic diagram of an electronic device provided in this embodiment; Figure 3 This is a schematic flowchart of a method for fabricating a microlens structure provided in this embodiment; Figure 4 for Figure 3 Corresponding process flow chart; Figure 5 This is the process diagram corresponding to step S13 provided in this embodiment; Figure 6 for Figure 1 A flowchart of the sub-steps corresponding to step S15; Figure 7 for Figure 6 Corresponding process flow chart; Figure 8 This is a schematic diagram of the blocking portion formed in sub-step S151 provided in this embodiment.

[0017] Icons: 1-Microlens structure; 10-Substrate layer; 100-Substrate layer body; 110-Substrate base; 11-First microlens; 12-Second microlens; 1101-Bottom surface; 1102-Sloping surface; 2-Electronic device; 20-Substrate; 200-Optoelectronic device layer; 2001-Optoelectronic device; 210-Photoelectric conversion layer; 220-Encapsulation layer; 13-Substrate material layer; 14-Mask material layer; 15-Imprint substrate; 150-Imprint groove; 140-Imprint base; 16-Microlens material layer; 17-Blocking unit; 170-Blocking part. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0020] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0021] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] It should be noted that, where there is no conflict, different features in the embodiments of this application can be combined with each other.

[0023] The inventors discovered through research that microlens arrays (MLAs) are key components in modern optical imaging and display systems, widely used in CMOS image sensors, augmented reality (AR), and virtual reality (VR). In CMOS image sensors, MLAs are used to focus incident light onto the photosensitive area of ​​a photodiode, thereby improving quantum efficiency and signal-to-noise ratio. In AR / VR display systems, MLAs are used to improve pixel light extraction efficiency, achieving high resolution and a wide field of view. However, all of these electronic devices face the optical mismatch problem of edge microlenses. For CMOS image sensors, microlenses located at the edges cannot effectively focus incident light onto the photoelectric device (i.e., the photodiode) due to a significant deviation in the chief ray angle (CRA) of the incident light relative to the central area. This results in decreased light collection efficiency, exacerbated shadowing effects, and severely impacts the uniformity of image quality. For AR / VR display systems, microlenses located at the edges have their optical axes perpendicular to the surface of the optoelectronic device (i.e., the light-emitting device), making it difficult to deflect the emitted light angle towards a large field of view. This means they cannot match the edge's requirements for the emitted light angle, thus limiting the display effect and light extraction efficiency of the system. The principal ray angle refers to the maximum angle of light that can be focused onto the optoelectronic device from the image sensor side.

[0024] Currently, to address the aforementioned issues, two approaches have been taken. First, the edge microlenses can be horizontally offset to match the angle of emitted or incident light at corresponding positions. However, this method requires independent design of the offset for each light-emitting device, significantly increasing the complexity of the layout. Furthermore, the asymmetrical gaps created by the offset between adjacent microlenses can lead to light leakage. Second, increasing the number of microlenses for each optoelectronic device can improve light collection efficiency. However, this significantly increases the manufacturing cost of electronic devices, and the spacing between adjacent microlenses is difficult to control precisely, increasing the manufacturing complexity. Moreover, even with multiple microlenses, their optical axes remain perpendicular to the optoelectronic device surface, and the edge regions still cannot effectively match the required angle of incident or emitted light. Therefore, how to effectively improve the matching capability of the microlens array to the angle of emitted or incident light at corresponding positions, thereby improving the light extraction or collection efficiency of electronic devices, has become a pressing technical problem for those skilled in the art.

[0025] In order to solve the aforementioned technical problems, the inventors have innovatively designed the following technical solutions, and the specific implementation scheme of this application will be described in detail below with reference to the accompanying drawings.

[0026] Please see Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of a microlens structure 1 provided in this embodiment. Figure 2 This is a schematic diagram of an electronic device 2 provided in this embodiment. The microlens structure 1 includes a substrate layer 10, a first microlens 11, and a second microlens 12. The substrate layer 10 has a first region AA1 and a second region AA2 surrounding the first region AA1. The substrate layer 10 includes a substrate layer body 100 and a plurality of substrate bases 110. The substrate bases 110 are fixed on the substrate layer body 100 and located in the second region AA2. The substrate base 110 includes a bottom surface 1101 and an inclined surface 1102 with a preset tilt angle α to the bottom surface 1101. In a direction perpendicular to the surface of the substrate layer body 100, the distance between the inclined surface 1102 and the corresponding bottom surface 1101 gradually decreases in the direction away from the first region AA1. The first microlens 11 is located on the substrate layer body 100 in the first region AA1, and the second microlens 12 is located on the inclined surface 1102 of the corresponding substrate base 110 in the second region AA2. Along the surface of the substrate layer body 100 and away from the first region AA1, the inclination angle α between the inclined surface 1102 and the bottom surface 1101 of the substrate base 110 gradually increases.

[0027] In this embodiment, the microlens structure 1 can be applied to electronic devices 2, for example, to CMOS image sensors, AR display systems or VR display systems. When the microlens structure 1 is applied to electronic devices 2, the substrate layer 10 can be formed on the substrate 20.

[0028] In this embodiment, the substrate layer 10 serves as the supporting foundation for the entire microlens structure 1. The substrate layer 10 is typically circular and is divided into a first region AA1 and a second region AA2. The first region AA1 is the central region of the substrate layer 10, i.e., the central region of the microlens structure 1, while the second region AA2 surrounds the first region AA1. One or more first microlenses 11 can be disposed in the first region AA1. The surface of the substrate layer body 100 is flat, and a substrate base 110 with an inclination angle α is fixed within the second region AA2. The substrate layer body 100 and the substrate base 110 are typically integrally formed. The inclination angle α of the substrate base 110 gradually increases along the surface of the substrate layer body 100 and away from the first region AA1. Using the central region as a reference, incident or outgoing light is incident or outgoing in the central region in a vertical direction. The closer to the edge, the larger the incident and outgoing light angles. Therefore, the tilt angle α of the microlens at the first region AA1 is 0 degrees, and there is no need to set the substrate base 110. Along the direction away from the first region AA1, the incident or outgoing light angle at each position also increases sequentially, and the tilt angle α of the substrate base 110 also increases sequentially. Thus, the tilt angle α of the second microlens 12 on the substrate base 110 also increases sequentially. In this way, by setting microlenses with tilt angle α that gradually increases along the direction away from the first region, each microlens can effectively match the outgoing or incident light angle at the corresponding position, thereby improving the light extraction efficiency or light collection efficiency at that position.

[0029] Furthermore, please see again Figure 1 and Figure 2 In this embodiment, the tilt angle α of the substrate base 110 at the same distance from the first region AA1 is the same. Thus, on the annular region of the same radius of the substrate layer 10, the tilt angle α of the microlens is kept consistent, so that the optical axis S1 of each microlens in the microlens structure 1 presents a circular distribution with the center of the substrate layer 10 as the center.

[0030] In this embodiment, multiple substrate bases 110 are arranged at intervals along a direction away from the first region AA1, with the same spacing between adjacent substrate bases 110. Similarly, the second microlenses 12 on the substrate bases 110 are also arranged at intervals along a direction away from the first region AA1, with the same spacing between adjacent second microlenses 12. The first microlens 11 is located at the center of the substrate layer 10, and the spacing between the first microlens 11 and the surrounding second microlenses 12 is also the same. This ensures that the microlenses are evenly spaced on the substrate layer 10, guaranteeing a neat arrangement and significantly reducing process complexity. Furthermore, the arrangement of the microlenses on the substrate layer 10 should be consistent with the arrangement of the optoelectronic devices 2001 in the electronic device 2, ensuring precise alignment between the microlenses and the optoelectronic devices 2001 to prevent light leakage. Each microlens can effectively match the emitted or incident light angle at the corresponding optoelectronic device 2001, thereby improving the light extraction or collection efficiency of the electronic device 2.

[0031] It is worth noting that the spacing between adjacent microlenses is not limited here and needs to be set according to the actual situation.

[0032] Furthermore, please see again Figure 1 and Figure 2 The first angle β1 formed by the optical axis S1 of the second microlens 12 and the direction S2 perpendicular to the bottom surface 1101 of the corresponding substrate base 110 is the same as the tilt angle α of the substrate base 110. In this embodiment, since the substrate base 110 has a tilt angle α, when the second microlens 12 is disposed on the substrate base 110, its optical axis S1 also has a tilt angle α, and the first angle β1 formed by its optical axis S1 and the direction perpendicular to the bottom surface 1101 of the corresponding substrate base 110 is the same as the tilt angle α. In this way, it is ensured that the second microlens 12 is precisely matched with the incident light angle or the outgoing light angle at this position.

[0033] In this embodiment, the first microlens 11 and the second microlens 12 are of the same type, and the first microlens 11 includes a spherical lens, an aspherical lens, or a freeform lens.

[0034] In this embodiment, the radius of curvature of the first microlens 11 is the same as that of the second microlens 12. The radius of curvature of the first microlens 11 is 1 micrometer to 50 micrometers. For example, the radius of curvature of the first microlens 11 is 1 micrometer, 10 micrometer, 20 micrometer, 30 micrometer, 40 micrometer and 50 micrometer, etc. The radius of curvature directly affects the focal length and light-gathering ability of the microlens, and the corresponding radius of curvature can be selected according to the actual situation.

[0035] Furthermore, in this embodiment, the refractive index of the second microlens 12 is greater than that of the substrate layer 10. Thus, when incident light strikes the surface of the second microlens 12, the incident light travels from a lower refractive index to a higher refractive index, resulting in a refraction angle smaller than the incident angle. The incident light converges towards the optical axis of the second microlens 12. When the incident light reaches the substrate layer 10, it enters the substrate layer 10 from the higher refractive index second microlens 12, resulting in a refraction angle greater than the incident angle. The incident light is deflected away from the optical axis, allowing the second microlens 12 to effectively converge the incident light onto the photodiode at that location.

[0036] When the emitted light hits the second microlens 12, it enters the high-refractive-index second microlens 12 from the low-refractive-index substrate layer 10, and passes from an optically less dense medium to an optically denser medium. The angle of refraction is smaller than the angle of incidence, and the light ray is deflected away from the optical axis. Then, the emitted light passes from the second microlens 12 to the outside air, and passes from an optically denser medium to an optically less dense medium. The angle of refraction is larger than the angle of incidence, and the emitted light is emitted at a larger angle of view, thereby expanding the field of view.

[0037] The refractive index of the first microlens 11 is the same as that of the second microlens 12. The refractive index of the second microlens 12 is 1.4 to 2.2. For example, the refractive index of the second microlens 12 is 1.4, 1.6, 1.8, 2 and 2.2.

[0038] The first microlens 11 is made of the same material as the second microlens 12. The material of the first microlens 11 includes a transparent polymer material, a glass material, or a dielectric material. In this embodiment, the transparent polymer material (e.g., optical resin) can be formed by embossing or hot reflow molding, the glass material has high stability and durability, and the dielectric material can be a high refractive index dielectric material, such as silicon nitride.

[0039] Based on the same inventive concept, please see Figure 2 , Figure 3 , Figure 4 and Figure 4 , Figure 3 This is a schematic flowchart of the fabrication method of a microlens structure 1 provided in this embodiment. Figure 4 for Figure 3 The corresponding process flow diagram, Figure 5 For the process diagram corresponding to step S13 provided in this embodiment, this application embodiment also provides a method for fabricating a microlens structure 1, the method including: Step S11: Provide a substrate material layer 13.

[0040] In this step, when the microlens structure 1 is applied to the electronic device 2 (e.g., a CMOS image sensor or an AR / VR display system), the substrate material layer 13 can be fabricated on the substrate 20 of the electronic device 2. The substrate 20 of the electronic device 2 includes a substrate (not shown in the figure) and an optoelectronic device layer 200 stacked together. Specifically, the substrate material layer 13 can be deposited on the substrate 20. In the direction perpendicular to the plane of the substrate 20, the thickness of the substrate material layer 13 ranges from 1.5 micrometers to 2 micrometers. The substrate material layer 13 can be a material with a relatively low etching rate in plasma containing fluorine radicals such as CF4 and SF6, such as alumina.

[0041] Step S12: A mask material layer 14 is formed on one side of the substrate material layer 13.

[0042] In this step, a mask material layer 14 is coated on the substrate material layer 13. The mask material layer 14 can be a UV-curable organic material.

[0043] In this embodiment, the mask material layer 14 is used for subsequent patterning processing.

[0044] Step S13: Pattern the mask material layer 14 to obtain the patterned mask material layer 14.

[0045] In this step, the mask material layer 14 can be patterned by imprinting to form an imprinting base 140 with a corresponding tilt angle α, such as... Figure 5 As shown.

[0046] Step S14: Based on the patterned mask material layer 14, the substrate material layer 13 is etched to form a substrate layer 10. The substrate layer 10 has a first region AA1 and a second region AA2 surrounding the first region AA1. The substrate layer 10 includes a substrate layer body 100 and a plurality of substrate bases 110. The substrate bases 110 are fixed on the substrate layer body 100 and located in the second region AA2. The substrate bases 110 include a bottom surface 1101 and an inclined surface 1102 with a preset tilt angle α to the bottom surface 1101. In the direction perpendicular to the surface of the substrate layer body 100, the distance between the inclined surface 1102 and the corresponding bottom surface 1101 gradually decreases in the direction away from the first region AA1.

[0047] In step S15, a first microlens 11 is fabricated on the substrate layer body 100 in the first region AA1, and a second microlens 12 is fabricated on the inclined surface 1102 corresponding to the substrate base 110 in the second region AA2, forming a microlens structure 1.

[0048] In the above scheme, by setting microlenses with tilt angle α that gradually increases in the direction away from the first region, each microlens can effectively match the outgoing light angle or the incoming light angle at the corresponding position, thereby improving the light output efficiency or light collection efficiency at that position.

[0049] Furthermore, prior to step S11, the method further includes: First, the tilt angle α of the second microlens 12 at the target position on the substrate layer 10 is determined in advance.

[0050] In this step, the outgoing light angle or the incident light angle at each target position is obtained, and the tilt angle α of the corresponding second microlens 12 is determined, that is, the optical axis tilt angle α of the second microlens 12. The tilt angle α of the second microlens 12 has a tolerance angle with respect to the outgoing light angle or the incident light angle. This tolerance angle ranges from 0° to 3°, and is expressed by the formula θ(x,y) = CRA(x,y) ± Δθ, where θ(x,y) represents the tilt angle α of the second microlens 12 at the target position, CRA(x,y) represents the outgoing light angle or the incident light angle at the target position, and Δθ represents the tolerance angle.

[0051] In this embodiment, the tilt angle α of the second microlens 12 on the substrate layer 10 can be designed specifically according to different optical parameters or application scenarios, and is not specifically limited here. It is applicable to CMOS image sensors of various sizes and resolutions as well as different types of AR / VR display systems, which significantly improves the flexibility of the microlens structure 1.

[0052] Next, an imprinting substrate 15 is fabricated based on the position of the second microlens 12 on the substrate layer 10 and the tilt angle α corresponding to the second microlens 12. The imprinting substrate 15 includes an imprinting groove 150 corresponding to the tilt angle α of the second microlens 12.

[0053] Furthermore, step S13 can be implemented in the following way.

[0054] The side of the imprinting substrate 15 with the imprinting groove 150 is imprinted towards the mask material layer 14, and an imprinting base 140 is formed on the side of the mask material layer 14 away from the substrate material layer 13, resulting in a patterned mask material layer 14.

[0055] In this step, please refer to Figure 5 One side of the imprinting groove 150 on the imprinting substrate 15 is transferred to the mask material layer 14 by nanoimprinting technology. On the side of the mask material layer 14 away from the substrate material layer 13, an imprinting base 140 with the opposite concavity and convexity to the imprinting groove 150 is pressed out.

[0056] Furthermore, step S14 can be implemented in the following way.

[0057] Based on the patterned mask material layer 14, the substrate material layer 13 is etched to transfer the pattern of the imprint base 140 on the mask material layer 14 onto the substrate material layer 13, thus obtaining the substrate layer 10.

[0058] In this step, the substrate material layer 13 is dry-etched based on the patterned mask material layer 14. The dry etching process can use F-based or Cl-based plasma gases, such as SF6, CF4, CHF3, C4F8, Cl2, BCl3, HCl, etc. During the etching process, etching is usually performed in a direction perpendicular to the substrate layer 10. The etching gas first etches away the patterned mask material layer 14, and then etches the substrate material layer 13. At the same etching rate, the thinner parts of the mask material layer 14 are etched through first, followed by the substrate material layer 13, while the thicker parts are etched through later. In this way, the shape of the patterned mask material layer 14 can be transferred to the substrate material layer 13 to obtain the substrate layer 10.

[0059] Further, please see Figure 6 and Figure 7 , Figure 6 for Figure 1 A flowchart illustrating the sub-steps corresponding to step S15. Figure 7 for Figure 6 The corresponding process diagram, step S15 can be implemented in the following way.

[0060] In sub-step S150, a microlens material layer 16 covering the substrate layer 10 is formed on the substrate layer 10.

[0061] In this step, a microlens material layer 16 is coated on the substrate layer 10. The microlens material layer 16 flatly covers the substrate layer 10. The microlens material layer 16 can be an organic lens material (e.g., various resin materials) or a deposited inorganic lens material (e.g., SiNx, SiOx).

[0062] In sub-step S151, a plurality of blocking units 17 for forming the first microlens 11 and the second microlens 12 are fabricated on the side of the microlens material layer 16 away from the substrate layer 10.

[0063] In this step, a barrier layer is first coated on the side of the microlens material layer 16 away from the substrate layer 10. Then, a photoresist layer is coated on the side of the barrier layer away from the substrate layer 10. Based on the photoresist layer, the barrier layer is patterned to form multiple barrier portions 170. (See [link to previous step]). Figure 8 , Figure 8This is a schematic diagram of the blocking portion 170 formed in sub-step S151 of this embodiment. The blocking portion 170 is correspondingly disposed with the substrate base 110, and the cross-sectional shape of the blocking portion 170 is rectangular in the direction perpendicular to the plane where the substrate layer 10 is located. Then, by heat reflow, the blocking portion 170 forms a blocking unit 17 under heat reflow, wherein the side of the blocking unit 17 away from the substrate layer 10 is arc-shaped. For example, the cross-sectional shape of the blocking portion 170 in the direction perpendicular to the plane where the substrate layer 10 is located can be semi-circular.

[0064] In sub-step S152, the microlens material layer 16 is etched based on the blocking unit 17 to transfer the pattern of the blocking unit 17 to the microlens material layer 16, forming a first microlens 11 on the substrate body 100 located in the first region AA1 and a second microlens 12 on the inclined surface 1102 of the corresponding substrate base 110 in the second region AA2, thus obtaining the microlens structure 1.

[0065] In this step, the microlens material layer 16 is dry etched based on the blocking unit 17. The etching is usually performed in a direction perpendicular to the substrate layer 10. At the same etching rate, the thinner part of the blocking unit 17 is etched through first and then the microlens material layer 16 is etched. The thicker part is etched through later and then the microlens material layer 16 is etched. When the substrate layer 10 is etched, its etching rate is almost 0. In this way, a second microlens 12 is formed on the inclined surface 1102 of the substrate base 110 in the second region AA2, which is consistent with the inclined surface 1102. A first microlens 11 is formed on the substrate layer body 100 in the first region AA1.

[0066] In this embodiment, a microlens material layer 16 with patterning capability can be directly coated on the substrate layer 10, and then a photoresist layer can be coated on the side of the microlens material layer 16 away from the substrate layer 10. The microlens material layer 16 is patterned, and after exposure and development, a first microlens 11 and a second microlens 12 are formed on the substrate layer body 100 and the substrate base 110 respectively by a hot reflow process.

[0067] Based on the same inventive concept, please see Figure 1 and Figure 2 This application also provides an electronic device 2, which includes a substrate 20 and the aforementioned microlens structures 1 provided in the embodiments of this application. The microlens structures 1 are disposed on one side of the substrate 20.

[0068] The substrate 20 includes a photoelectric device layer 200, which includes a plurality of photoelectric devices 2001. The second included angle β2 formed by the optical axis S1 of the second microlens 12 of the microlens structure 1 corresponding to the photoelectric device 2001 and the direction S3 perpendicular to the plane where the photoelectric device 2001 is located is the same as the tilt angle α of the substrate base 110 of the microlens structure 1 corresponding to the photoelectric device 2001.

[0069] In the above scheme, the electronic device 2 can be a CMOS image sensor or an AR / VR display system. Microlenses with an angle α that gradually increases in the direction away from the first region are provided on one side of the substrate 20, namely, a first microlens 11 and a second microlens 12, so that each microlens can effectively match the outgoing light angle or the incoming light angle at its corresponding position. Thus, when the electronic device 2 is a CMOS image sensor, when incident light enters the image sensor, the photoelectric device 2001 of the image sensor can obtain optimal light-gathering efficiency, significantly improving the uniformity of imaging, and effectively eliminating the shadow effect in the edge region of the image sensor, significantly improving the quantum efficiency of the photoelectric device 2001 in the edge region.

[0070] When the electronic device 2 is an AR / VR display system, when the emitted light is emitted from the optoelectronic device 2001 to the microlens structure 1, the emitted light from the optoelectronic device 2001 can be emitted at the optimal emission angle, which effectively improves the light emission efficiency of the edge area of ​​the display system and expands the field of view of the display system.

[0071] Furthermore, please see again Figure 2 The substrate 20 further includes a substrate (not shown) and a photoelectric conversion layer 210 located on the substrate. A photoelectric device layer 200 is located on the side of the photoelectric conversion layer 210 away from the substrate. The photoelectric conversion layer 210 is used to convert the optical signal received by the photoelectric device 2001 in the photoelectric device layer 200 into an electrical signal, or to drive the photoelectric device 2001 in the photoelectric device layer 200 to emit light. In this embodiment, when the electronic device 2 is a CMOS image sensor, the photoelectric conversion layer 210 is used to convert the optical signal received by the photoelectric device 2001 in the photoelectric device layer 200 into an electrical signal. When the electronic device 2 is an AR / VR display system, the photoelectric conversion layer 210 is used to drive the photoelectric device 2001 in the photoelectric device layer 200 to emit light.

[0072] In this embodiment, the substrate 20 further includes an encapsulation layer 220, which is located between the photoelectric conversion layer 210 and the microlens structure 1.

[0073] The optoelectronic device 2001 includes a photosensitive device or a light-emitting device. In this embodiment, when the electronic device 2 is a CMOS image sensor, the optoelectronic device 2001 is a photosensitive device, such as a photodiode. When the electronic device 2 is an AR / VR display system, the optoelectronic device 2001 is a light-emitting device.

[0074] Furthermore, please see again Figure 2 In this embodiment, the orthographic projection of the substrate base 110 on the substrate 20 covers the orthographic projection of the corresponding optoelectronic device 2001 on the substrate 20. The orthographic projection of the first microlens 11 on the substrate 20 covers the orthographic projection of the corresponding optoelectronic device 2001 on the substrate 20, and the orthographic projection of the second microlens 12 on the substrate 20 covers the orthographic projection of the corresponding optoelectronic device 2001 on the substrate 20. This ensures that the substrate base 110 and the second microlens 12 thereon, and the substrate layer body 100 and the first microlens 11 thereon, can effectively cover the corresponding optoelectronic device 2001. This ensures that incident light accurately reaches the optoelectronic device 2001 when passing through the first microlens 11 or the second microlens 12, and that outgoing light emitted from the optoelectronic device 2001 accurately reaches the first microlens 11 or the second microlens 12, avoiding optical loss caused by mismatch in position or size between the optoelectronic device 2001 and each microlens.

[0075] In summary, this application provides a microlens structure, a method for fabricating the microlens structure, and an electronic device. The microlens structure includes a substrate layer, a first microlens, and a second microlens. The substrate layer includes a substrate layer body and multiple substrate bases. The substrate bases are fixed to the substrate layer body and located in a second region. Each substrate base includes a bottom surface and an inclined surface with a preset tilt angle to the bottom surface. The distance between the inclined surface and the corresponding bottom surface gradually decreases in the direction away from the first region. The first microlens is located on the substrate layer body, and the second microlens is located on the inclined surface of the corresponding substrate base. In the direction away from the first region, the tilt angle between the inclined surface of the substrate base and the bottom surface gradually increases. By setting microlenses with tilt angles that gradually increase in the direction away from the first region, the above structure enables each microlens to effectively match the emitted light angle or incident light angle at its corresponding position, thereby improving the light extraction efficiency or light collection efficiency at that position.

[0076] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A microlens structure, characterized in that, The microlens structure includes: A substrate layer having a first region and a second region surrounding the first region, the substrate layer including a substrate layer body and a plurality of substrate bases, the substrate bases being fixed to the substrate layer body and located in the second region, the substrate bases including a bottom surface and an inclined surface having a preset tilt angle with the bottom surface, the distance between the inclined surface and the corresponding bottom surface gradually decreasing in the direction away from the first region in a direction perpendicular to the surface of the substrate layer body; A first microlens is located on the substrate layer body in the first region; The second microlens is located on the inclined surface of the substrate base in the second region; Along the surface of the substrate layer body and away from the first region, the angle of inclination between the inclined surface of the substrate base and the bottom surface gradually increases.

2. The microlens structure as described in claim 1, characterized in that, The substrate bases that are at the same distance from the first region have the same tilt angle; Multiple substrate bases are arranged at intervals along a direction away from the first region, and the spacing between adjacent substrate bases is the same.

3. The microlens structure as described in claim 1, characterized in that, The first angle formed by the optical axis of the second microlens and the direction perpendicular to the bottom surface of the corresponding substrate base is the same as the tilt angle of the substrate base; The first microlens is of the same type as the second microlens, and the first microlens can be a spherical lens, an aspherical lens, or a freeform surface lens. The radius of curvature of the first microlens is the same as that of the second microlens, and the radius of curvature of the first microlens is 1 micrometer to 50 micrometers.

4. The microlens structure as described in claim 1, characterized in that, The refractive index of the second microlens is greater than that of the substrate layer; The refractive index of the first microlens is the same as that of the second microlens, and the refractive index of the second microlens is 1.4~2.2; The first microlens is made of the same material as the second microlens, and the material of the first microlens includes a transparent polymer material, a glass material, or a dielectric material.

5. A method for fabricating a microlens structure, characterized in that, The method includes: Provide a substrate material layer; A mask material layer is formed on one side of the substrate material layer; The mask material layer is patterned to obtain a patterned mask material layer; The substrate material layer is etched based on the patterned mask material layer to form a substrate layer. The substrate layer has a first region and a second region surrounding the first region. The substrate layer includes a substrate layer body and a plurality of substrate bases. The substrate bases are fixed on the substrate layer body and located in the second region. The substrate base includes a bottom surface and an inclined surface with a preset tilt angle to the bottom surface. In a direction perpendicular to the surface of the substrate layer body, the distance between the inclined surface and the corresponding bottom surface gradually decreases in the direction away from the first region. A first microlens is fabricated on the substrate layer body in the first region, and a second microlens is fabricated on the inclined surface corresponding to the substrate base in the second region, thereby forming the microlens structure.

6. The method for fabricating the microlens structure as described in claim 5, characterized in that, Prior to the step of providing a substrate material layer, the method further includes: The tilt angle of the second microlens at the target position on the substrate layer is predetermined; An imprinting substrate is fabricated based on the position of the second microlens on the substrate layer and the tilt angle corresponding to the second microlens, wherein the imprinting substrate includes an imprinting groove corresponding to the tilt angle of the second microlens. The step of patterning the mask material layer to obtain a patterned mask material layer includes: The side of the imprinting substrate with the imprinting groove is imprinted towards the mask material layer, and an imprinting base is formed on the side of the mask material layer away from the substrate material layer to obtain the patterned mask material layer. The step of etching the substrate material layer based on the patterned mask material layer to form the substrate layer includes: Based on the patterned mask material layer, the substrate material layer is etched to transfer the pattern of the imprinted base on the mask material layer onto the substrate material layer, thus obtaining the substrate layer.

7. The method for fabricating the microlens structure as described in claim 5, characterized in that, The step of fabricating a first microlens on the substrate layer body in the first region and fabricating a second microlens on the inclined surface corresponding to the substrate base in the second region to form the microlens structure includes: A microlens material layer covering the substrate layer is formed on the substrate layer; Multiple blocking units for forming the first microlens and the second microlens are fabricated on the side of the microlens material layer away from the substrate layer; Based on the blocking unit, the microlens material layer is etched to transfer the pattern of the blocking unit to the microlens material layer, forming the first microlens on the substrate layer body located in the first region and the second microlens on the inclined surface of the corresponding substrate base located in the second region, thus obtaining the microlens structure.

8. An electronic device, characterized in that, The electronic device includes a substrate and a microlens structure as described in any one of claims 1-4, wherein the microlens structure is disposed on one side of the substrate; The substrate includes an optoelectronic device layer, which includes multiple optoelectronic devices. The second angle formed by the optical axis of the second microlens of the microlens structure corresponding to the optoelectronic device and the direction perpendicular to the plane where the optoelectronic device is located is the same as the tilt angle of the substrate base of the microlens structure corresponding to the optoelectronic device.

9. The electronic device as claimed in claim 8, characterized in that, The substrate further includes a substrate and a photoelectric conversion layer located on the substrate; The optoelectronic device layer is located on the side of the optoelectronic conversion layer away from the substrate; The photoelectric conversion layer is used to convert the optical signal received by the photoelectric device in the photoelectric device layer into an electrical signal, or to drive the photoelectric device in the photoelectric device layer to emit light. The optoelectronic device includes a photosensitive device or a light-emitting device.

10. The electronic device as claimed in claim 8, characterized in that, The orthogonal projection of the substrate base onto the substrate covers the orthogonal projection of the corresponding optoelectronic device onto the substrate. The orthogonal projection of the first microlens onto the substrate covers the orthogonal projection of the optoelectronic device corresponding to the first microlens onto the substrate, and the orthogonal projection of the second microlens onto the substrate covers the orthogonal projection of the optoelectronic device corresponding to the second microlens onto the substrate.

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