Optical path steering element and manufacturing method therefor, optical system, and electronic device

Abstract

Disclosed in the present application are an optical path steering element and a manufacturing method therefor, an optical system, and an electronic device, to reduce the costs of the optical path steering element and decrease the surface flatness of the optical path steering element. The light path steering element comprises a substrate of a plastic material, the substrate comprising a plurality of substrate surfaces, and a laminated structure is provided on at least one of the substrate surfaces, and comprising a filling layer and a film layer, wherein the filling layer is arranged on the substrate surface, and the flatness of the surface of the filling layer on the side facing away from the substrate is less than the flatness of the substrate surface; and the film layer is arranged on the side of the filling layer facing away from the substrate.

Description

Optical path turning element and manufacturing method thereof, optical system and electronic equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on July 27, 2023, with application number 202310933717.0 and application name “Optical path turning element and its manufacturing method, optical system and electronic equipment”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the technical field of electronic equipment, and in particular to an optical path turning element and a manufacturing method thereof, an optical system and an electronic device. Background Art

[0004] Optical systems are crucial components in a variety of electronic devices, including terminals, lidar, projectors, laser printers, and head-up displays. They process optical information from these devices, enabling them to perform imaging functions. Optical systems typically incorporate light-path deflection elements, such as prisms, to deflect light paths. Using prisms not only effectively improves the optical performance of electronic devices but also optimizes their layout within them, ensuring they match the device's structural design.

[0005] Traditional prisms are mostly made of glass and typically processed by cold grinding, resulting in relatively high weight and cost. Compared to glass prisms, plastic prisms can be mass-produced using injection molding, offering certain advantages in weight and cost. However, due to the high shrinkage of plastic, the shape of plastic prisms varies significantly after solidification and cooling, resulting in relatively poor surface flatness, which affects their optical performance.

[0006] Summary of the Invention

[0007] The present application provides an optical path turning element and a manufacturing method thereof, an optical system and an electronic device, so as to reduce the cost of the optical path turning element and reduce the surface flatness of the optical path turning element.

[0008] In a first aspect, the present application provides an optical path deflection element, comprising a plastic substrate, the substrate comprising multiple substrate surfaces, at least one of which may be provided with a laminated structure, each laminated structure comprising a filling layer and a film layer. The filling layer may be provided on the corresponding substrate surface, with the surface flatness of the filling layer facing away from the substrate being less than that of the substrate surface, and the film layer may be provided on the side of the filling layer facing away from the substrate.

[0009] In this application, the surface flatness of the substrate formed by injection molding of plastic is relatively high due to its high shrinkage rate. However, by adding the aforementioned laminated structure, the surface flatness of the resulting optical path deflection element is significantly reduced, thereby effectively improving the optical performance of the optical path deflection element. Furthermore, compared to traditional glass optical path deflection elements, the optical path deflection element in this application uses plastic as the substrate material, thereby reducing costs.

[0010] In some embodiments, the flatness PV1 of the substrate surface satisfies: 1 μm ≤ PV1 ≤ 100 μm. The substrate is formed by an injection molding process, and the flatness of the substrate surface can be controlled according to the specific material of the substrate and relevant parameters during the injection molding process.

[0011] For example, the material of the substrate includes, but is not limited to, plastics such as polymethyl methacrylate, polyvinyl chloride, amorphous polyolefin, and amorphous polycarbonate.

[0012] In some embodiments, the flatness PV2 of the filling layer surface facing away from the substrate satisfies: PV2 ≤ 1 μm. The filling layer can be formed on the substrate surface by spin coating and then embossed using a high-precision template to ensure that the flatness of the filling layer surface facing away from the substrate is less than that of the substrate surface.

[0013] In some embodiments, the flatness PV3 of the surface of the film layer facing away from the filling layer satisfies: 0.01 um≤PV3≤10 um.

[0014] In some embodiments, the coefficient of thermal expansion (CTE1) of the substrate and the coefficient of thermal expansion (CTE2) of the filling layer satisfy the following relationship: 0.1 ≤ CTE2 / CTE1 ≤ 10. Having a similar coefficient of thermal expansion of the filling layer to that of the substrate ensures that the filling layer and substrate have good weather resistance in high and low temperature environments, thereby helping to improve the reliability of the optical path turning element.

[0015] Exemplarily, the thermal expansion coefficient CTE1 of the substrate satisfies: 20E-6 / °C≤CTE1≤150E-6 / °C.

[0016] In some embodiments, the thickness D2 of the filling layer satisfies the following condition: 1 μm ≤ D2 ≤ 700 μm. By controlling the thickness of the filling layer within this range, it is possible to avoid interfacial adhesion between the filling layer and the substrate due to a too thin filling layer, while also reducing the risk of poor surface flatness after curing shrinkage caused by an excessively thick filling layer.

[0017] In some embodiments, the refractive index n1 of the substrate and the refractive index n2 of the filling layer satisfy the following relationship: 0.6 ≤ n2 / n1 ≤ 1.5. When the optical path deflection element causes internal reflection of light, the light must sequentially pass through the substrate and the filling layer before being reflected by the film layer. By ensuring that the refractive index of the substrate and the filling layer satisfy this relationship, aberrations caused by the refractive index difference between the filling layer and the substrate can be reduced.

[0018] In some embodiments, the film layer may be a reflective film or an anti-reflection film. In the case of a reflective film, light may be internally reflected or externally reflected from the surface on which the film layer is located. In the case of an anti-reflection film, the film layer may transmit the surface on which the film layer is located and enter the interior of the optical path turning element.

[0019] In some embodiments, the optical path turning element can be a reflector. In this case, at least one substrate surface of the substrate can be a plane, spherical or aspherical surface. Accordingly, the reflector formed according to the substrate can be a plane reflector, a spherical reflector or an aspherical reflector.

[0020] In some other embodiments, the light path turning element may be a prism, such as but not limited to a triangular prism, a rectangular prism, a parallelogram prism, a trapezoidal prism, a wedge prism or a special-shaped prism, and the like.

[0021] In a second aspect, the present application further provides an optical system, which may include a lens and an optical deflection element according to any embodiment of the first aspect. The optical deflection element may be used to deflect light entering the optical system toward the lens, and the lens may be used to project the light onto an imaging surface of the optical system. Due to the low surface flatness of the optical deflection element, the optical performance of the optical system is improved.

[0022] In some embodiments, the optical path deflection element may be a prism. The prism may include an incident surface, an exit surface, and a reflective surface. At least the reflective surface may include the aforementioned laminated structure, and the film layer of the laminated structure of the reflective surface is a reflective film. The incident surface is positioned toward the light input direction of the optical system, and the exit surface is positioned toward the lens. Light enters the prism through the incident surface, is reflected by the reflective surface, and then passes through the exit surface to the lens outside the prism, thereby achieving a deflection of the optical path.

[0023] In some embodiments, at least one of the incident surface or the reflective surface may be a surface with optical focal length, so that the optical path turning element may also function as a lens, thereby helping to further improve the optical performance of the optical system.

[0024] In a third aspect, the present application further provides an optical system, which may include a transmitter, a receiver, and an optical path deflection element according to any embodiment of the first aspect. The optical path deflection element may be used to reflect light emitted by the transmitter toward the outside world, and to reflect light from the outside world toward the receiver. Due to the low surface flatness of the optical path deflection element, the optical performance of the optical system is improved.

[0025] In some embodiments, an optical path deflection element is rotatably disposed within an optical system. The optical path deflection element may include multiple reflective surfaces arranged circumferentially, each reflective surface comprising a laminated structure, wherein the film layer of the laminated structure is a reflective film. A transmitter and a receiver may be located on either side of a polygonal rotating mirror. When the polygonal rotating mirror rotates, the incident angle of light emitted by the transmitter onto one of the reflective surfaces of the polygonal rotating mirror changes, thereby correspondingly changing the exit angle of light reflected from the reflective surface toward the external space. This allows scanning of the external space within a certain angular range. Accordingly, the receiver can also receive light within a certain angular range reflected by the other reflective surfaces.

[0026] In a fourth aspect, the present application further provides an electronic device, which may include a housing and the optical system according to any of the embodiments of the second or third aspects, wherein the optical system may be disposed within the housing. For example, the electronic device may be a terminal device, a projector, a head-up display, a laser radar, a laser printer, or the like, and the optical system may be used to process optical information from these electronic devices, enabling the electronic device to perform imaging or other specific functions.

[0027] In a fifth aspect, the present application further provides a method for preparing an optical path turning element, which may include the following steps:

[0028] injection molding to form a base body, which may include a plurality of base surfaces;

[0029] Spin coating a filling layer on at least one substrate surface;

[0030] Using a template to emboss the filling layer so that the flatness of the surface of the filling layer facing away from the substrate is less than the flatness of the substrate surface;

[0031] Curing and demoulding the filling layer;

[0032] The coating is performed on the side of the filling layer facing away from the substrate to form a film layer.

[0033] The optical path deflection element prepared by the above method significantly reduces surface flatness by adding a laminated structure to the substrate surface, thereby effectively improving the optical performance of the optical path deflection element. Furthermore, compared to traditional glass optical path deflection elements, the optical path deflection element in this application uses plastic as the substrate material, thereby reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG1 is a schematic diagram of a partial cross-sectional structure of an optical path turning element provided in an embodiment of the present application;

[0035] FIG2 is a schematic structural diagram of an optical path turning element provided in an embodiment of the present application;

[0036] FIG3 is a schematic structural diagram of another optical path turning element provided in an embodiment of the present application;

[0037] FIG4 is a schematic diagram of the cross-sectional structure of another optical path turning element provided in an embodiment of the present application;

[0038] 5a to 5h are schematic cross-sectional views of several other optical path turning elements provided in embodiments of the present application;

[0039] FIG6 is a schematic diagram of a partial structure of an electronic device provided in an embodiment of the present application;

[0040] FIG7 is a schematic structural diagram of another optical path turning element provided in an embodiment of the present application;

[0041] FIG8 is a schematic structural diagram of another electronic device provided in an embodiment of the present application.

[0042] Figure markings: 100-optical path turning element; 101-incident surface; 102-exit surface; 103-reflecting surface; 110-substrate; 120-laminated structure; 120a-first laminated structure; 120b-second laminated structure; 120c-third laminated structure; 121-filling layer; 122-film layer; 1, 2-electronic equipment; 1100, 2100-housing; 1110-light inlet; 1200-camera module; 1210, 2200-optical system; 1211-lens; 1220-circuit board; 1230-photosensitive chip; 1240-mounting seat; 2210-transmitter; 2220-receiver. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present application clearer, the embodiments of the present application will be further described in detail with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein. The same reference numerals in the figures represent the same or similar structures, and thus their repeated description will be omitted. The words expressing position and direction described in the embodiments of the present application are all explained using the accompanying drawings as examples, but changes may be made as needed, and the changes made are all included in the scope of protection of the present application. The drawings in the embodiments of the present application are only used to illustrate the relative position relationship and do not represent the true proportion.

[0044] It should be noted that the following description sets forth specific details to facilitate understanding of the present application. However, the embodiments of the present application can be implemented in a variety of other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotations of the embodiments of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0045] Optical systems exist in a variety of electronic devices, such as but not limited to terminal devices, projectors, head-up displays, lidars, laser printers, etc. Optical systems can be used to process optical information of these electronic devices to enable the electronic devices to achieve imaging or other specific functions.

[0046] With the rapid development of electronic devices, their appearance and performance are constantly improving, which also places higher demands on the optical performance of optical systems. Based on this, the optical systems of various electronic devices are currently equipped with light path turning elements, such as prisms and reflectors. Taking prisms as an example, prisms can change the propagation path of light in optical systems. Using prisms can not only improve the optical performance of optical systems, but in some scenarios, it can also optimize the layout of optical systems in electronic devices, helping to achieve miniaturization of electronic devices.

[0047] Traditional prisms are mostly made of glass, which is often processed by cold grinding. Glass has a relatively high density, resulting in relatively high weight and cost. Compared to glass prisms, plastic prisms can be mass-produced using injection molding. Thanks to the lower cost and density of plastic, plastic prisms are significantly superior to glass prisms in terms of weight and cost. However, due to the high shrinkage of plastic, the shape of plastic prisms varies significantly after solidification and cooling, and the surface flatness (peak to valley, PV) of the prisms is relatively poor, which limits the large-scale application of plastic prisms.

[0048] To address the above-mentioned issues, embodiments of the present application provide an optical path deflection element, as well as an optical system and electronic device utilizing the optical path deflection element. The optical path deflection element utilizes a plastic substrate, and the substrate surface is treated to reduce its flatness. This allows the optical path deflection element to have the advantages of low cost and light weight of a conventional plastic prism while also achieving excellent surface flatness, thereby enhancing the optical performance of the electronic device utilizing the optical path deflection element. The optical path deflection element provided in embodiments of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0049] FIG1 is a schematic diagram of a partial cross-sectional structure of an optical path turning element provided in an embodiment of the present application. Referring to FIG1 , in an embodiment of the present application, the optical path turning element 100 may include a substrate 110 and a laminated structure 120. The substrate 110 is made of plastic, and the substrate 110 may include a plurality of substrate surfaces. It can also be understood that the substrate 110 is a polyhedron. At least one substrate surface of the substrate 110 may be provided with the above-mentioned laminated structure 120, and the laminated structure 120 may serve as a functional layer of the optical path turning element, so that the optical path turning element 100 can achieve a higher optical quality while realizing the optical path turning function. It should be noted that FIG1 only shows the partial structure of a substrate surface of the substrate 110 provided with the laminated structure 120, rather than the complete shape of the substrate 110.

[0050] In the embodiment of the present application, the substrate 110 can be formed by an injection molding process. The material of the substrate 110 includes, but is not limited to, plastics such as polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), amorphous polyolefin, and amorphous polycarbonate. For ease of understanding, FIG1 illustrates the unevenness of the substrate surface after injection molding using sawtooth-shaped protrusions or depressions. These protrusions or depressions do not limit the specific shape of the substrate surface.

[0051] In some embodiments, the optical path turning element 100 can be a reflector. In this case, at least one substrate surface of the substrate 110 can be a plane, a spherical or an aspherical surface. Accordingly, the reflector formed according to the substrate 110 can be a plane reflector, a spherical reflector or an aspherical reflector.

[0052] In some embodiments, the optical path turning element 100 can be a prism. Along the length direction perpendicular to the base 110, the cross-sectional shape of the base can be a right triangle, an isosceles triangle, a rectangle, a parallelogram, a trapezoid, a wedge or some other regular or irregular polygonal shapes. Accordingly, the prism formed according to the base 110 can be a triangular prism (including a right-angle prism, an isosceles prism), a rectangular prism, a parallelogram prism, a trapezoidal prism, a wedge prism or an irregular prism, etc.

[0053] Continuing with reference to FIG1 , the laminated structure 120 may include a filling layer 121 and a film layer 122, wherein the filling layer 121 may be disposed on the surface of the substrate 110, and the film layer 122 may be disposed on the side of the filling layer 121 facing away from the surface of the substrate 110, that is, the filling layer 121 is located between the surface of the substrate 110 and the film layer 122, and the side of the film layer 122 facing away from the filling layer 121 is the outer surface of the optical path turning element. In a specific implementation, the filling layer 121 may be formed on the surface of the substrate 110 by spin coating, and then the filling layer 121 may be embossed using a high-precision template so that the flatness of the side of the filling layer 121 facing away from the substrate is less than the flatness of the surface of the substrate 110; thereafter, the filling layer 121 is cured and demolded, and the film layer 122 is formed on the surface of the cured filling layer 121 by a coating process to meet the optical transmittance requirements of the optical path turning element 100.

[0054] As mentioned above, due to the high shrinkage rate of plastic materials, the surface flatness of the substrate 110 formed by injection molding thereof is relatively large, making it difficult to meet the optical performance requirements. However, by adding the above-mentioned laminated structure 120, the surface flatness of the optical path turning element finally obtained can be significantly reduced, thereby effectively improving the optical performance of the optical path turning element 100. In this embodiment, the flatness PV1 of the substrate surface of the substrate 110 formed by injection molding generally satisfies: 1um≤PV1≤100um, and thus, the flatness PV2 of the surface of the side of the filling layer 121 away from the substrate 110 satisfies: PV2≤1um. The surface of the side of the film layer 122 away from the filling layer 121 serves as the outer surface of the optical path turning element 100, and its flatness PV3 satisfies: 0.01um≤PV3≤10um.

[0055] In the embodiment of the present application, the filling layer 121 may be a photoresist-like material. After being imprinted using a mold, the filling layer 121 may be cured by ultraviolet (UV) curing or thermal curing.

[0056] The thermal expansion coefficient (CTE2) of the filling layer 121 is close to the thermal expansion coefficient (CTE1) of the substrate 110, ensuring that the filling layer 121 and the substrate 110 have good weather resistance in high and low temperature environments. In this embodiment, the thermal expansion coefficient (CTE1) of the substrate 110 satisfies the following conditions: 20E-6 / °C ≤ CTE1 ≤ 150E-6 / °C, and the thermal expansion coefficient (CTE2) of the filling layer 121 and the thermal expansion coefficient (CTE1) of the substrate 110 satisfy the following conditions: 0.1 ≤ CTE2 / CTE1 ≤ 10.

[0057] Furthermore, if the filling layer 121 is too thin, its interfacial adhesion with the substrate 110 will be poor, affecting the structural stability of the optical path turning element 100. If the filling layer 121 is too thick, there is a risk of poor surface flatness due to curing shrinkage. Taking the above into consideration, in this embodiment, the thickness D2 of the filling layer 121 satisfies the following conditions: 1 μm ≤ D2 ≤ 700 μm.

[0058] Continuing with reference to FIG. 1 , in some embodiments, the film layer 122 may be a reflective film. In a specific implementation, the film layer 122 may be a metal reflective film, or may be implemented as a dielectric film. It is easy to understand that the surface of the optical path turning element 100 on which the laminated structure 120 is provided is a reflective surface. In an electronic device employing the optical path turning element 100, incident light may be deflected after being reflected by the reflective surface. The reflection achieved by the reflective surface may be either external or internal, and may be determined based on the specific application scenario of the optical path turning element.

[0059] In the event of internal reflection, incident light can sequentially pass through the substrate 110 and the filling layer 121 from the other surfaces of the optical path deflection element 100 (which can be understood as the incident surface of the optical path deflection element 100 ), reflect from the film layer 122, and then exit from the other surfaces of the optical path deflection element 100 (which can be understood as the exit surface of the optical path deflection element 100 ). In this case, since light must sequentially pass through the substrate 110 and the filling layer 121, to reduce aberrations caused by the refractive index difference between the filling layer 121 and the substrate 110, the filling layer 121 can have a refractive index close to that of the substrate 110. In this embodiment, the refractive index n2 of the filling layer 121 and the refractive index n1 of the substrate 110 can satisfy the following: 0.6 ≤ n2 / n1 ≤ 1.5.

[0060] In the case of external reflection, the incident light does not pass through the base 110 and the filling layer 121 , but is directly reflected by the film layer 122 and then turned. At this time, no requirements are imposed on the refractive index of the filling layer 121 and the base 110 .

[0061] In some other embodiments, the film layer 122 may also be an anti-reflection film, in which case the film layer 122 may also be implemented by a dielectric film. It is easy to understand that the surface of the optical path turning element 100 provided with the laminated structure 120 serves as a light-transmitting surface that allows light to pass through. In an electronic device employing the optical path turning element 100, external light may pass through this light-transmitting surface to enter the optical path turning element 100, in which case this light-transmitting surface may serve as the incident surface of the optical path turning element 100. Alternatively, light entering the optical path turning element 100 may also pass through this light-transmitting surface to exit the optical path turning element 100, in which case this light-transmitting surface may serve as the exit surface of the optical path turning element 100.

[0062] It can be seen that when the light-transmitting surface serves as the incident surface, light sequentially passes through the film layer 122, the filling layer 121, and the substrate 110 to enter the interior of the optical path deflection element 100. When the light-transmitting surface serves as the exit surface, light sequentially passes through the substrate 110, the filling layer 121, and the film layer 122 and is emitted from the optical path deflection element 100. To reduce aberrations caused by the difference in refractive index between the filling layer 121 and the substrate 110, in this embodiment, the filling layer 121 can also have a refractive index close to that of the substrate 110. In specific design, the refractive index n2 of the filling layer 121 and the refractive index n1 of the substrate 110 can satisfy the following relationship: 0.6 ≤ n2 / n1 ≤ 1.5.

[0063] Based on the optical path turning element 100 in the above embodiment, the present invention further provides a method for preparing the optical path turning element 100. The method comprises the following steps:

[0064] Step 1: Injection molding to form a base 110, which may include multiple base surfaces. Exemplarily, the material of the base 110 includes, but is not limited to, plastics such as PMMA, PVC, amorphous polyolefin, and amorphous polycarbonate.

[0065] Step 2: Spin-coat a filling layer 121 on the surface of at least one substrate 110. For example, the filling layer 121 may be a photoresist-like material.

[0066] Step 3: Use a template to emboss the filling layer 121 so that the flatness of the surface of the filling layer 121 facing away from the substrate 110 is less than the flatness of the surface of the substrate 110 .

[0067] In this step, the flatness PV3 of the surface of the filling layer 121 facing away from the substrate 110 satisfies: 0.01um≤PV3≤10um; the thickness D2 of the filling layer 121 satisfies: 1um≤D2≤700um; the thermal expansion coefficient CTE2 of the filling layer 121 and the thermal expansion coefficient CTE1 of the substrate 110 satisfy: 0.1≤CTE2 / CTE1≤10.

[0068] Step 4: Curing and demoulding the filling layer 121. In a specific implementation, the filling layer 121 can be cured by UV or heat.

[0069] Step 5: Coating is performed on the side of the filling layer 121 away from the substrate 110 to form a film layer 122. The film layer 122 may be a reflective film or an anti-reflective film, and the flatness PV3 of the surface of the film layer 122 away from the filling layer 121 satisfies: 0.01um≤PV3≤10um.

[0070] As mentioned above, in the embodiment of the present application, the optical path turning element can be a reflector, or can be a prism of various shapes. The following examples illustrate several prisms and the optical systems and electronic equipment using these prisms.

[0071] FIG2 is a schematic diagram of the cross-sectional structure of an optical path turning element 100 provided in an embodiment of the present application. Referring to FIG2 , in this embodiment, the optical path turning element 100 can be a right-angle prism. It should be noted that the prism numbers below are the same as the prism numbers of the optical path turning element 100. The surfaces where the two right-angled sides of the prism 100 are located serve as the incident surface 101 and the exit surface 102, respectively, and the surface where the hypotenuse is located serves as the reflecting surface 103. Among them, at least the reflecting surface of the prism may include the above-mentioned laminated structure. For example, in the embodiment shown in FIG2 , the reflecting surface of the prism includes a laminated structure, and the incident surface 101 and the exit surface 102 do not include a laminated structure, that is, the incident surface 101 and the exit surface 102 can be directly formed using the substrate surface.

[0072] The laminated structure of the reflective surface is defined as the first laminated structure 120a, and the film layer 122 of the first laminated structure 120a is a reflective film. In the prism 100 shown in Figure 2, the light is internally reflected at the reflective surface 103. Specifically, the light enters the prism 100 from the incident surface, and then is reflected at the reflective surface 103. The reflected light is emitted from the exit surface 102, thereby achieving the redirection of the light path. At this time, for the reflective surface 103, the light must pass through the base 110 and the filling layer 121 in sequence before reaching the film layer 122 of the first laminated structure 120a. Therefore, in order to reduce the aberration caused by the refractive index difference between the filling layer 121 and the base 110, the refractive index n2 of the filling layer 121 of the first laminated structure 120a and the refractive index n1 of the base 110 can satisfy: 0.6≤n2 / n1≤1.5. Illustratively, in this embodiment, the refractive index n2 of the filling layer 121 and the refractive index of the matrix n1 satisfy: n2 / n1≈0.956.

[0073] In the embodiment of the present application, in order to ensure that light has good transmittance during the transmission process of the prism 100 and to reduce the difficulty of injection molding of the prism 100, the material of the base 110 of the prism 100 can be specifically selected from amorphous polyolefin with high transmittance and high optical quality. The thermal expansion coefficient CTE1 of the base 110 is approximately 80E-6 / °C. After the base 110 is injection molded, the flatness PV1 of the surface of the base 110 is approximately 1um. When forming the first stacked structure 120a, a filling layer 121 with a thickness of approximately 200um is first spin-coated on the surface of the base 110 where the hypotenuse of the base 110 is located. The filling layer 121 is then embossed using a mold with good flatness, and then cured and demolded, so that the thickness of the final filling layer 121 is approximately 100um. At this time, the flatness PV2 of the surface of the filling layer 121 facing away from the base 110 can meet the use requirements. Finally, a film layer 122 is deposited on the side of the filling layer 121 facing away from the substrate 110 .

[0074] FIG3 is a schematic diagram of the structure of another optical path deflection element 100 provided in an embodiment of the present application. Referring to FIG3 , in this embodiment, the optical path deflection element 100 can also be a right-angled prism, with the two right-angled sides of the prism 100 serving as the incident surface 101 and the exit surface 102, respectively, and the hypotenuse serving as the reflective surface 103. Different from the aforementioned embodiment, in this embodiment, in addition to the first stacked structure 120a of the reflective surface 103, the incident surface 101 and the exit surface 102 may also respectively include the aforementioned stacked structures. The stacked structure of the incident surface 101 is defined as the second stacked structure 120b, and the stacked structure of the exit surface 102 is defined as the third stacked structure 120c. According to the introduction of the aforementioned embodiment, the film layers of the second stacked structure 120b and the third stacked structure 120c are both transmissive films, so that light passes through the second stacked structure 120b to enter the prism 100, and light reflected by the reflective surface 103 in the prism 100 is emitted through the third stacked structure 120c.

[0075] Of course, in some other embodiments, one of the incident surface 101 or the exit surface 102 may include a laminated structure, and these forms of the prism 100 are all within the scope of the embodiments of the present application.

[0076] It should be understood that when the incident surface 101 and the exit surface 102 are respectively provided with a second stacked structure 120b and a third stacked structure 120c, the refractive index n2 of the filling layer of the second stacked structure 120b and the refractive index of the matrix n1 may satisfy: 0.6≤n2 / n1≤1.5, and the refractive index n2 of the filling layer of the third stacked structure 120c and the refractive index of the matrix n1 may satisfy: 0.6≤n2 / n1≤1.5. FIG4 is a schematic diagram of the cross-sectional structure 100 of another optical path turning element provided in an embodiment of the present application. Referring to FIG4 , in this embodiment, the optical path turning element 100 may also be a right-angle prism, or the optical path turning element 100 may be regarded as a structure after the optical path turning element 100 shown in FIG2 is rotated 180°. The surface where the hypotenuse of the triangular prism 100 is located serves as a reflective surface 103 , and the reflective surface 103 of the triangular prism includes a first stacked structure 120 a , and a film layer 122 of the first stacked structure 120 a serves as a reflective layer.

[0077] In the prism 100 shown in FIG4 , light is externally reflected at the reflecting surface 103, that is, the light does not enter the interior of the prism 100, but is directly reflected at the outer surface of the film layer 122 and then turned. Therefore, this embodiment does not require the refractive index of the filling layer 121 of the first stacked structure 120a and the substrate 110. For example, the material of the substrate 110 can be plastic. After the substrate 110 is injection molded, a filling layer 121 with a thickness of approximately 200 μm is spin-coated on the surface of the substrate 110 where the hypotenuse of the substrate 110 is located. The filling layer 121 is then embossed using a mold with good flatness, and then cured and demolded so that the flatness PV of the surface of the filling layer 121 facing away from the substrate 110 meets the use requirements. The thickness of the finally formed filling layer 121 can be approximately 100 μm. Finally, a film layer (reflective film) 122 is plated on the side of the filling layer 121 facing away from the substrate 110.

[0078] In addition, in the case of external reflection, the surfaces where the other two right-angled sides of the prism 100 are located do not need to have reflection or transmission functions, so the two surfaces may not include a laminated structure, which effectively simplifies the manufacturing process during the manufacturing process of the prism 100 and reduces the cost of the prism 100.

[0079] In some other possible embodiments of the present application, at least one of the two surfaces of the prism other than the reflective surface may be a surface having optical power. That is, the prism may have at least one non-planar surface, which may be either convex or concave, though this application does not impose any limitations thereon. The following examples illustrate several prisms that include surfaces having optical power.

[0080] 5a to 5h , which illustrate schematic cross-sectional structures of several possible triangular prisms 100, each triangular prism 100 may include an incident surface 101, an exit surface 102, and a reflective surface 103. The reflective surface 103 of the triangular prism 100 includes a laminated structure, while the incident surface 101 and the exit surface 102 of the triangular prism 100 do not. The laminated structure of the reflective surface 103 of the triangular prism 100 is defined as a first laminated structure 120a, and the film layer 122 of the first laminated structure 120a is a reflective film.

[0081] For example, in the embodiment shown in FIG5a, the incident surface 101 of the prism 100 is a convex surface, and the exit surface 102 is a plane; in the embodiment shown in FIG5b, the incident surface 101 of the prism 100 is a concave surface, and the exit surface 102 is a plane; in the embodiment shown in FIG5c, the incident surface 101 of the prism 100 is a plane, and the exit surface 102 is a convex surface; in the embodiment shown in FIG5d, the incident surface 101 of the prism 100 is a plane, and the exit surface 102 is a concave surface. 2 is a concave surface; in the embodiment shown in FIG5e, the incident surface 101 of the prism 100 is a convex surface, and the exit surface 102 is a concave surface; in the embodiment shown in FIG5f, the incident surface 101 of the prism 100 is a concave surface, and the exit surface 102 is a convex surface; in the embodiment shown in FIG5g, the incident surface 101 and the exit surface 102 of the prism 100 are both convex surfaces; in the embodiment shown in FIG5h, the incident surface 101 and the exit surface 102 of the prism 100 are both concave surfaces.

[0082] The prisms 100 provided in the above examples are all capable of causing light to be internally reflected therein. Light enters the prism 100 from the incident surface 101, and then is reflected at the reflecting surface 103. The reflected light is emitted from the exit surface 102, thereby achieving the redirection of the light path. For the reflecting surface 103, the light must pass through the substrate 110 and the filling layer 121 in sequence before reaching the film layer 122 of the first stacked structure 120a. Therefore, in order to reduce the aberration caused by the refractive index difference between the filling layer 121 and the substrate 110, the refractive index n2 of the filling layer 121 of the first stacked structure 120a and the refractive index n1 of the substrate 110 can satisfy: 0.6≤n2 / n1≤1.5. Exemplarily, in this embodiment, the refractive index n2 of the filling layer 121 and the refractive index n1 of the substrate satisfy: n2 / n1≈0.956.

[0083] In addition, in order to ensure that light has good transmittance when propagating within the prism 100 and to reduce the difficulty of injection molding of the prism 100, the material of the base 110 of the prism 100 can be specifically selected from amorphous polyolefins with high transmittance and high optical quality. The thermal expansion coefficient CTE1 of the base 110 is approximately 80E-6 / °C. After the base 110 is injection molded, the flatness PV1 of the surface of the base 110 is approximately 1 μm. When forming the first stacked structure 120a, a filling layer 121 with a thickness of approximately 200 μm is first spin-coated on the surface of the base 110 where the hypotenuse of the base 110 is located. The filling layer 121 is then embossed using a mold with good flatness, and then cured and demolded so that the flatness PV of the surface of the filling layer 121 facing away from the base 110 meets the use requirements. The thickness of the final filling layer 121 can be approximately 100 μm. Finally, a film layer (reflective film) 122 is coated on the side of the filling layer 121 facing away from the substrate 110 .

[0084] FIG6 is a schematic diagram of a partial structure of an electronic device 1 provided in an embodiment of the present application, showing the partial structure of the electronic device 1 including a camera module. Referring to FIG6 , in the embodiment of the present application, the electronic device 1 can be a mobile phone, a tablet personal computer, a laptop computer, a personal digital assistant (PDA), a camera, a personal computer, a notebook computer, an in-vehicle device, a wearable device, augmented reality (AR) glasses, an AR helmet, virtual reality (VR) glasses or a VR helmet, or other devices with photo and video recording functions.

[0085] Electronic device 1 includes a housing 1100 and a camera module 1200 disposed within housing 1100. Housing 1100 is provided with a light inlet 1110, which connects the interior of the electronic device to the exterior of the electronic device. Camera module 1200 is used to capture ambient light that enters the interior of the electronic device through light inlet 1110.

[0086] The camera module 1200 may include an optical system 1210, a circuit board 1220, and a photosensitive chip 1230. The optical system 1210 includes a light-input side and a light-output side. The light-input side of the optical system 1210 is disposed toward the light-input hole 1110, while the light-output side is disposed toward the circuit board 1220. The photosensitive chip 1230 is disposed on the side of the circuit board 1220 that faces the optical system 1210, and the photosensitive chip 1230 is located on the imaging surface of the optical system 1210. The optical system 1210 may include a lens 1211 and an optical path deflection element 100. The optical path deflection element 100 may be used to deflect light entering the electronic device through the light-input hole 1110 toward the lens 1211. The lens 1211 is used to project the light onto the photosensitive chip 1230 located on the imaging surface of the optical system 1210, so that the photosensitive chip 1230 collects light from the light-output side of the optical system 1210 and generates a signal.

[0087] In this embodiment, the optical path turning element 100 can adopt the prism in any of the embodiments of Figures 2 to 5h above. In specific implementation, the camera module can also include a mounting base 1240, on which the prism 100 can be set, so that the mounting base 1240 can be used to fix the prism 100 inside the electronic device. The incident surface 101 of the prism 100 is set toward the light inlet 1110, and the exit surface 102 is set toward the lens 1211. When light enters the interior of the electronic device through the light inlet 1110, the light enters the prism 100 through the incident surface 101 and is reflected by the reflective surface 103 of the prism 100. At this time, the light propagating along the x-axis is reflected to propagate along the y-axis. Finally, the light is emitted from the exit surface 102 of the prism 100 to the lens 1211 outside the prism 100.

[0088] It can be understood that the light propagating along the x-axis direction is redirected to propagate along the y-axis direction by utilizing the optical path turning element 100. With this design, the components of the camera module 1200 can be transformed from being arranged along the x-direction to being arranged along the y-direction. Usually, the light inlet 1110 of the electronic device 1 is provided on the back side of the housing 1100. Therefore, the aforementioned x-direction can be understood as the thickness direction of the electronic device 1. In this case, the y-direction can be the width direction of the electronic device 1 or the length direction of the electronic device 1. Compared to the thickness direction, the electronic device 1 is larger in the width direction or the length direction. Therefore, the optical path turning element 100 can make the arrangement of the components of the camera module 1200 in the y-axis direction more flexible and convenient.

[0089] FIG7 is a schematic structural diagram of another optical path turning element 100 provided in an embodiment of the present application. Referring to FIG7 , in an embodiment of the present application, the optical path turning element 100 may be a multi-faceted mirror. It should be noted that the number of the multi-faceted mirror hereinafter is the same as the number of the optical path turning element 100. The multi-faceted mirror 100 is provided with a plurality of reflecting surfaces 103 in the circumferential direction, and a certain angle is formed between any two adjacent reflecting surfaces 103. For example, in the present embodiment, the multi-faceted mirror 100 includes four reflecting surfaces 103, and the angle between any two adjacent reflecting surfaces 103 in the circumferential direction is approximately 90°. Each reflecting surface 103 of the multi-faceted mirror 100 includes the laminated structure shown in FIG1 , and the film layers of each laminated structure are respectively reflecting films.

[0090] In the embodiment shown in Figure 7, each reflective surface 103 of the polygonal mirror 100 is capable of reflecting light outward, preventing it from entering the interior of the polygonal mirror 100. Therefore, this embodiment does not impose any requirements on the refractive index of the filling layer and the substrate of the laminated structure on each reflective surface 103. In this embodiment, the substrate of the polygonal mirror 100 can be made of PMMA, which is relatively low-cost and has high moldability. Its thermal expansion coefficient CTE1 is approximately 80E-6 / °C. After injection molding, the substrate surface flatness PV1 is approximately 10 μm. To form each laminated structure, a filling layer with a thickness of approximately 400 μm is first spin-coated on each substrate surface around the substrate. The filling layer is then embossed using a mold with high flatness. After curing and demolding, the filling layer surface on the side facing away from the substrate has a flatness PV2 that meets the required surface flatness. Finally, a reflective film is applied to the side of the filling layer facing away from the substrate.

[0091] Figure 8 is a schematic diagram of the structure of another electronic device 2 provided in an embodiment of the present application. Referring to Figure 8 , the electronic device 2 in this embodiment is described using a laser radar as an example. The electronic device 2 includes a housing 2100 and an optical system 2200 disposed within the housing 2100. The housing 2100 may be partially or entirely made of a translucent material, allowing the optical system 2200 to transmit light to or receive light from the external space through the housing 2100.

[0092] The optical system 2200 may include a transmitter 2210, a receiver 2220, and an optical path deflection element 100. The optical path deflection element 100 may be used to reflect light (e.g., pulsed laser) emitted by the transmitter 2210 toward the outside world. When the light detects a target object (e.g., a road, a pedestrian, a vehicle, etc.), it is reflected. The optical path deflection element 100 may then reflect the light reflected from the target object back toward the receiver 2220, allowing the electronic device 2 to detect road conditions or the environment based on the received light.

[0093] In this embodiment, the optical path deflection element 100 can be a polygonal mirror as shown in FIG. 6 . The polygonal mirror 100 is rotatably disposed within the optical system 2200. In one implementation, the optical system 2200 can further include a drive motor (not shown) that can be used to drive the polygonal mirror 100 to rotate about its axis. The transmitter 2210 and the receiver 2220 can be located on either side of the polygonal mirror 100. When the drive motor rotates the polygonal mirror 100, the incident angle of light emitted by the transmitter 2210 on one of the reflective surfaces of the polygonal mirror 100 changes, thereby correspondingly changing the exit angle of light reflected from the reflective surface toward the external space. This allows scanning of the external space within a certain angular range. Correspondingly, the receiver 2220 can also receive light reflected from the other reflective surfaces within a certain angular range.

[0094] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. An optical path turning element, characterized in that: A substrate comprising a plastic material, the substrate comprising a plurality of substrate surfaces, at least one of the substrate surfaces being provided with a laminated structure, the laminated structure comprising a filling layer and a film layer, wherein: The filling layer is arranged on the surface of the substrate, and the flatness of the surface of the filling layer on a side away from the substrate is less than the flatness of the surface of the substrate; The film layer is arranged on a side of the filling layer away from the substrate.

2. The optical path turning element according to claim 1, characterized in that: The flatness PV1 of the substrate surface satisfies: 1um≤PV1≤100um.

3. The optical path deflection element according to claim 1 or 2, characterized in that: The flatness PV2 of the surface of the filling layer on one side away from the substrate satisfies: PV2≤1 um.

4. The optical path deflection element according to any one of claims 1 to 3, characterized in that: The flatness PV3 of the surface of the film layer on one side away from the filling layer satisfies: 0.01um≤PV3≤10um.

5. The optical path turning element according to any one of claims 1 to 4, characterized in that: The thermal expansion coefficient CTE1 of the substrate and the thermal expansion coefficient CTE2 of the filling layer satisfy: 0.1≤CTE2 / CTE1≤10.

6. The optical path turning element according to any one of claims 1 to 5, characterized in that: The thermal expansion coefficient CTE1 of the substrate satisfies: 20E-6 / °C≤CTE1≤150E-6 / °C.

7. The optical path turning element according to claim 1 or 6, characterized in that: The thickness D2 of the filling layer satisfies: 1um≤D2≤700um.

8. The optical path deflection element according to any one of claims 1 to 7, characterized in that: The refractive index n1 of the substrate and the refractive index n2 of the filling layer satisfy: 0.6≤n2 / n1≤1.

5.

9. The optical path turning element according to any one of claims 1 to 8, characterized in that: The film layer is a reflective film or an anti-reflective film.

10. The optical path turning element according to any one of claims 1 to 9, characterized in that: The optical path turning element includes a reflector, a prism, a trapezoidal prism, a wedge-shaped prism, a parallelogram prism or a special-shaped prism.

11. An optical system, characterized in that: It comprises a lens and an optical path turning element as described in any one of claims 1 to 10, wherein the optical path turning element is used to turn the light entering the optical system toward the lens, and the lens is used to project the light onto an imaging surface of the optical system.

12. The optical system according to claim 11, wherein: The optical path turning element is a prism, which includes an incident surface, an exit surface and a reflective surface. At least the reflective surface includes the stacked structure, and the film layer of the stacked structure of the reflective surface is a reflective film. The incident surface is set toward the light input direction of the optical system, and the exit surface is set toward the lens.

13. An optical system, characterized in that: It comprises a transmitter, a receiver and an optical path turning element as described in any one of claims 1 to 10, wherein the optical path turning element is used to reflect the light emitted by the transmitter to the external space, and reflect the light in the external space to the receiver.

14. The optical system according to claim 13, wherein: The optical path turning element is rotatably disposed in the optical system. The optical path turning element includes a plurality of reflecting surfaces arranged along a circumferential direction. Each of the reflecting surfaces includes the stacked structure, and the film layer of the stacked structure is a reflecting film.

15. An electronic device, characterized in that: The optical system comprises a housing and the optical system according to any one of claims 11 to 14, wherein the optical system is arranged in the housing.

16. A method for preparing an optical path turning element, characterized in that: include: injection molding to form a base body, wherein the base body includes a plurality of base body surfaces; Spin coating a filling layer on at least one surface of the substrate; Using a template to emboss the filling layer, so that the flatness of a surface of the filling layer on a side away from the substrate is less than the flatness of a surface of the substrate; Curing and demoulding the filling layer; The film layer is formed by coating the side of the filling layer away from the substrate.

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