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

Abstract

The invention discloses a light path turning element, a manufacturing method thereof, an optical system and electronic equipment, and aims to reduce the cost of the light path turning element and reduce the surface flatness of the light path turning element. The light path turning element comprises a base body made of a plastic material, the base body comprises a plurality of base body surfaces, at least one base body surface is provided with a laminated structure, the laminated structure comprises a filling layer and a film layer, the filling layer is arranged on the base body surface, and the flatness of the surface of the side, away from the base body, of the filling layer is smaller than that of the base body surface; the film layer is arranged on the side, away from the base body, of the filling layer.

Description

Technical Field

[0001] 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 equipment. Background Art

[0002] The optical system is an important component in various electronic devices such as terminal equipment, laser radar, projector, laser printer, head-up display, etc. It can be used to process the optical information of electronic devices so that the electronic devices can realize imaging functions. The optical system is generally equipped with a light path deflection element for deflecting the light path, such as a prism. The use of prisms can not only effectively improve the optical performance of electronic devices, but also optimize the layout of the optical system in electronic devices, so that the optical system can match the structural design of the electronic devices.

[0003] Traditional prisms are mostly made of glass, and are generally processed by cold grinding, which results in relatively high weight and cost of the prisms. Compared with glass prisms, plastic prisms can be mass-produced by injection molding, so they have certain advantages in weight and cost. However, due to the high shrinkage rate of plastic materials, the shape of plastic prisms varies greatly after solidification and cooling, which results in relatively poor surface flatness of plastic prisms, affecting their optical performance. Summary of the invention

[0004] 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.

[0005] In a first aspect, the present application provides an optical path turning element, which includes a substrate made of plastic material, the substrate including multiple substrate surfaces, at least one substrate surface may be provided with a laminated structure, and each laminated structure may include a filling layer and a film layer. The filling layer may be provided on the corresponding substrate surface, and the flatness of the surface of the filling layer on the side away from the substrate is less than the flatness of the substrate surface, and the film layer is provided on the side of the filling layer away from the substrate.

[0006] In the present application, the plastic material has a relatively high shrinkage rate, so the surface flatness of the substrate formed by injection molding is relatively large. By adding the above-mentioned laminated structure, 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. In addition, compared with the traditional glass-based optical path turning element, the optical path turning element in the present application uses plastic as the base material, so the cost is also reduced.

[0007] In some embodiments, the flatness PV1 of the substrate surface satisfies: 1um≤PV1≤100um. 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 in the injection molding process.

[0008] Exemplarily, the material of the substrate includes, but is not limited to, plastics such as polymethyl methacrylate, polyvinyl chloride, amorphous polyolefin, and amorphous polycarbonate.

[0009] In some embodiments, the flatness PV2 of the surface of the filling layer on the side away from the substrate satisfies: PV2≤1um. The filling layer can be formed on the surface of the substrate by spin coating, and then the filling layer is embossed using a high-precision template so that the flatness of the surface of the filling layer on the side away from the substrate is less than the flatness of the substrate surface.

[0010] In some embodiments, the flatness PV3 of the surface of the film layer on the side facing away from the filling satisfies: 0.01 um≤PV3≤10 um.

[0011] In some embodiments, the thermal expansion coefficient CTE1 of the substrate and the thermal expansion coefficient CTE2 of the filling layer satisfy: 0.1≤CTE2 / CTE1≤10. The thermal expansion coefficient of the filling layer is similar to that of the substrate, which can ensure that the filling layer and the substrate have good weather resistance in high and low temperature environments, thereby helping to improve the reliability of the optical path turning element.

[0012] Exemplarily, the thermal expansion coefficient CTE1 of the substrate satisfies: 20E-6 / °C≤CTE1≤150E-6 / °C.

[0013] In some embodiments, the thickness D2 of the filling layer satisfies: 1um≤D2≤700um. By controlling the thickness of the filling layer within this range, it is possible to avoid affecting the interfacial adhesion between the filling layer and the substrate due to the filling layer being too thin, and to reduce the risk of poor surface flatness after curing shrinkage due to the filling layer being too thick.

[0014] In some embodiments, the refractive index n1 of the substrate and the refractive index n2 of the filling layer satisfy: 0.6≤n2 / n1≤1.5. When the optical path turning element causes internal reflection of light, the light must pass through the substrate and the filling layer in sequence before being reflected at the film layer. By making the refractive index of the substrate and the refractive index of the filling layer satisfy the above relationship, the aberration caused by the difference in refractive index between the filling layer and the substrate can be reduced.

[0015] In some embodiments, the film layer may be a reflective film or an anti-reflection film. In the case where the film layer is a reflective film, light may be internally reflected or externally reflected on the surface where the film layer is located; in the case where the film layer is an anti-reflection film, the film layer may be transmitted through the surface where the film layer is located and enter the interior of the optical path turning element.

[0016] 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, a spherical surface, or an aspherical surface. Accordingly, the reflector formed according to the substrate can be a plane reflector, a spherical reflector, or an aspherical reflector.

[0017] 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-shaped prism or a special-shaped prism, and the like.

[0018] In a second aspect, the present application further provides an optical system, which may include a lens and an optical path deflection element in any embodiment of the first aspect, wherein the optical path deflection element may be used to deflect light entering the optical system and then project it toward the lens, and the lens may be used to project the light onto an imaging surface of the optical system. Since the surface flatness of the optical path deflection element is relatively small, the optical performance of the optical system is improved.

[0019] In some embodiments, the optical path turning element may be a prism, and the prism may include an incident surface, an exit surface, and a reflective surface, at least the reflective surface may include the above-mentioned laminated structure, and the film layer of the laminated structure of the reflective surface is a reflective film, the incident surface is arranged toward the light input direction of the optical system, and the exit surface is arranged toward the lens. The light enters the prism through the incident surface, is reflected at the reflective surface of the prism, and then passes through the exit surface to the lens outside the prism, so that the light path can be turned.

[0020] 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.

[0021] In a third aspect, the present application further provides an optical system, which may include a transmitter, a receiver, and an optical path turning element in any embodiment of the first aspect, wherein the optical path turning element may be used to reflect light emitted by the transmitter to an external space, and reflect light in the external space to the receiver. Since the surface flatness of the optical path turning element is relatively small, the optical performance of the optical system is improved.

[0022] In some embodiments, the optical path turning element can be rotatably disposed in the optical system, and the optical path turning element can include a plurality of reflective surfaces arranged along the circumferential direction, each reflective surface includes a laminated structure, and the film layer of the laminated structure is a reflective film. The transmitter and the receiver can be located on both sides of the multi-faceted rotating mirror, respectively. When the multi-faceted rotating mirror rotates, the incident angle of the light emitted by the transmitter to one of the reflective surfaces of the multi-faceted rotating mirror will change, so that the exit angle of the light reflected by the reflective surface to the external space will also change accordingly, so that the external space can be scanned within a certain angle range; accordingly, the receiver can also receive the light within a certain angle range reflected by other reflective surfaces.

[0023] In a fourth aspect, the present application further provides an electronic device, which may include a housing and an optical system in any of the embodiments of the second aspect or the third aspect, and the optical system may be disposed in the housing. Exemplarily, the electronic device may be a terminal device, a projector, a head-up display, a laser radar, a laser printer, etc., and the optical system may be used to process optical information of these electronic devices, so that the electronic device can achieve imaging or other specific functions.

[0024] In a fifth aspect, the present application also provides a method for preparing an optical path turning element, which may include the following steps:

[0025] injection molding to form a base body, which may include a plurality of base surfaces;

[0026] Spin coating a filling layer on at least one substrate surface;

[0027] Using a template to emboss the filling layer, so that the flatness of the surface of the filling layer on the side away from the substrate is less than the flatness of the surface of the substrate;

[0028] The filling layer is cured and demoulded;

[0029] The coating is performed on the side of the filling layer facing away from the substrate to form a film layer.

[0030] The optical path turning element prepared by the above method significantly reduces the surface flatness of the optical path turning element obtained by adding a laminated structure on the surface of the substrate, thereby effectively improving the optical performance of the optical path turning element. In addition, compared with the traditional optical path turning element made of glass, the optical path turning element in the present application uses plastic as the substrate material, so the cost is also reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of a partial cross-sectional structure of an optical path turning element provided in an embodiment of the present application;

[0032] Figure 2 A schematic diagram of the structure of an optical path turning element provided in an embodiment of the present application;

[0033] Figure 3 A schematic diagram of the structure of another optical path turning element provided in an embodiment of the present application;

[0034] Figure 4 A schematic diagram of the cross-sectional structure of another optical path turning element provided in an embodiment of the present application;

[0035] Figure 5a to Figure 5h Schematic diagram of the cross-sectional structure of several other optical path turning elements provided in the embodiments of the present application;

[0036] Figure 6 A schematic diagram of a partial structure of an electronic device provided in an embodiment of the present application;

[0037] Figure 7 A schematic diagram of the structure of another optical path turning element provided in an embodiment of the present application;

[0038] Figure 8 A schematic diagram of the structure of another electronic device provided in an embodiment of the present application.

[0039] Reference numerals:

[0040] 100-optical path turning element; 101-incident surface; 102-exit surface; 103-reflection surface; 110-substrate; 120-laminated structure;

[0041] 120a-first stacked structure; 120b-second stacked structure; 120c-third stacked structure; 121-filling layer; 122-film layer;

[0042] 1, 2-electronic equipment; 1100, 2100-housing; 1110-light inlet; 1200-camera module; 1210, 2200-optical system;

[0043] 1211-lens; 1220-circuit board; 1230-photosensitive chip; 1240-mounting seat; 2210-transmitter; 2220-receiver. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical scheme and advantages of the present application clearer, the embodiments of the present application will be further described in detail below in conjunction with the accompanying drawings. However, the example implementation can be implemented in various forms and should not be construed as being limited to the implementations 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 illustrated by taking 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 of the embodiments of the present application are only used to illustrate the relative position relationship and do not represent the true proportion.

[0045] It should be noted that specific details are described in the following description to facilitate understanding of the present application. However, the embodiments of the present application can be implemented in a variety of other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the embodiments of the present application. Therefore, the present application is not limited to the specific implementation methods disclosed below.

[0046] 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.

[0047] With the rapid development of electronic devices, their appearance and performance are constantly improving, which also puts higher requirements on the optical performance of optical systems. Based on this, optical systems of various electronic devices are currently equipped with optical path turning elements, such as prisms and reflectors. Taking prisms as an example, prisms can change the propagation path of light in optical systems. The use of prisms can not only improve the optical performance of optical systems, but also optimize the layout of optical systems in electronic devices in some scenarios, which helps to achieve miniaturization of electronic devices.

[0048] Traditional prisms are mostly made of glass, which is mostly processed by cold grinding. The density of glass is relatively high, resulting in relatively high weight and cost of glass prisms. Compared with glass prisms, plastic prisms can be mass-produced by injection molding, and thanks to the lower cost and lower density of plastic materials, plastic prisms are significantly better than glass prisms in weight and cost. However, due to the high shrinkage rate of plastic materials, the shape of plastic prisms varies greatly after solidification and cooling, and the surface flatness (peak to valley, PV) of the prism is relatively poor, which still limits the large-scale application of plastic prisms.

[0049] In view of the above problems, the embodiments of the present application provide an optical path turning element and an optical system and an electronic device using the optical path turning element. The optical path turning element uses a plastic material as a substrate, and reduces its flatness by processing the surface of the substrate, so that the optical path turning element has the advantages of low cost and light weight of ordinary plastic prisms, and can also achieve good surface flatness, thereby improving the optical performance of the electronic device using the optical path turning element. The optical path turning element provided in the embodiments of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0050] Figure 1 A partial cross-sectional structural diagram of an optical path turning element provided in an embodiment of the present application. Figure 1As shown, in the 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 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 Figure 1 Only a partial structure of a substrate surface of the substrate 110 provided with the laminated structure 120 is shown, rather than the complete shape of the substrate 110 .

[0051] In the embodiment of the present application, the substrate 110 can be formed by injection molding, and 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, Figure 1 The unevenness of the substrate surface after injection molding is illustrated by using sawtooth-shaped protrusions or depressions, and these protrusions or depressions do not limit the specific shape of the substrate surface.

[0052] 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 by the substrate 110 can be a plane reflector, a spherical reflector or an aspherical reflector.

[0053] In some embodiments, the optical path turning element 100 can be a prism. Along the length direction perpendicular to the substrate 110, the cross-sectional shape of the substrate can be a right triangle, an isosceles triangle, a rectangle, a parallelogram, a trapezoid, a wedge or some other regular or irregular polygonal shape. Correspondingly, the prism formed according to the substrate 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-shaped prism or a special-shaped prism, etc.

[0054] Continue to refer Figure 1, the stacked 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 surface of the filling layer 121 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 surface of the film layer 122 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 surface of the filling layer 121 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.

[0055] 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, and it is difficult to meet the optical performance requirements. 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.

[0056] In the embodiment of the present application, the filling layer 121 may be a photoresist-like material. After being printed using a mold, the filling layer 121 may be cured by ultraviolet (UV) curing or thermal curing.

[0057] The thermal expansion coefficient CTE2 of the filling layer 121 is close to the thermal expansion coefficient CTE1 of the substrate 110 to ensure 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: 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: 0.1≤CTE2 / CTE1≤10.

[0058] In addition, if the thickness of the filling layer 121 is too thin, the interface adhesion between the filling layer 121 and the substrate 110 will be poor, affecting the structural stability of the optical path turning element 100, while 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: 1um≤D2≤700um.

[0059] Continue to refer Figure 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 by a dielectric film. It is easy to understand that the surface of one side of the optical path turning element 100 provided with the laminated structure 120 is a reflective surface. In an electronic device using the optical path turning element 100, the incident light may be reflected by the reflective surface and then turned. The reflection realized by the reflective surface may be an external reflection or an internal reflection, which may be determined according to the specific application scenario of the optical path turning element.

[0060] In the case of internal reflection, the incident light can pass through the substrate 110 and the filling layer 121 in sequence from the other surfaces of the optical path turning element 100 (which can be understood as the incident surface of the optical path turning element 100), and after being reflected by the film layer 122, it can be emitted from the other surfaces of the optical path turning element 100 (which can be understood as the exit surface of the turning element 100). In this case, since the light must pass through the substrate 110 and the filling layer 121 in sequence, in order to reduce the aberration caused by the difference in refractive index 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: 0.6≤n2 / n1≤1.5.

[0061] In the case of external reflection, the incident light does not pass through the substrate 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 substrate 110 .

[0062] In some other embodiments, the film layer 122 can also be an anti-reflection film, in which case the film layer 122 can also be implemented by a dielectric film. It is easy to understand that the surface of one side of the optical path turning element 100 provided with the laminated structure 120 is a light transmission surface that allows light to penetrate. In an electronic device using the optical path turning element 100, external light can pass through the light transmission surface to enter the optical path turning element 100, and the light transmission surface can be used as the incident surface of the optical path turning element 100; or, the light entering the optical path turning element 100 can also pass through the light transmission surface and be emitted from the optical path turning element 100, and the light transmission surface can be used as the exit surface of the optical path turning element 100.

[0063] It can be seen that when the light transmission surface is used as the incident surface, the light passes through the film layer 122, the filling layer 121 and the substrate 110 in sequence to enter the light path turning element 100, and when the light transmission surface is used as the exit surface, the light passes through the substrate 110, the filling layer 121 and the film layer 122 in sequence and is emitted from the light path turning element 100. In order to reduce the aberration 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: 0.6≤n2 / n1≤1.5.

[0064] Based on the optical path turning element 100 in the above embodiment, the embodiment of the present application further provides a method for preparing the optical path turning element 100, and the preparation method comprises the following steps:

[0065] Step 1: Injection molding to form a substrate 110, which may include a plurality of substrate surfaces. Exemplarily, the material of the substrate 110 includes, but is not limited to, plastics such as PMMA, PVC, amorphous polyolefin, and amorphous polycarbonate.

[0066] Step 2: Spin-coat a filling layer 121 on the surface of at least one substrate 110. Exemplarily, the filling layer 121 may be a photoresist-like material.

[0067] Step three: 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 smaller than the flatness of the surface of the substrate 110 .

[0068] 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.

[0069] Step 4: Curing and demoulding the filling layer 121. In a specific implementation, the filling layer 121 can be cured by UV or heat.

[0070] 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.

[0071] As mentioned above, in the embodiments of the present application, the optical path turning element may be a reflector, or may be a prism of various shapes. Several prisms and optical systems and electronic devices using these prisms are illustrated below.

[0072] Figure 2 This is a schematic diagram of a cross-sectional structure of an optical path turning element 100 provided in an embodiment of the present application. Figure 2 As shown, in this embodiment, the optical path turning element 100 can be a right-angle prism. It should be noted that the number of the prism below is the same as the number of the optical path turning element 100. The surfaces where the two right-angle sides of the prism 100 are located are respectively used as the incident surface 101 and the exit surface 102, and the surface where the hypotenuse is located is used as the reflection surface 103. Among them, at least the reflection surface of the prism may include the above-mentioned laminated structure. For example, in Figure 2 In the illustrated embodiment, the reflective surface of the prism includes a laminated structure, while 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.

[0073] 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. Figure 2 In the prism 100 shown, the light is internally reflected at the reflection surface 103. Specifically, the light enters the prism 100 from the incident surface, and then is reflected at the reflection surface 103. The reflected light is emitted from the exit surface 102, thereby realizing the redirection of the light path. At this time, for the reflection 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 difference in refractive index 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.

[0074] In the embodiment of the present application, in order to ensure that the light has good transmittance during the transmission of the prism 100 and reduce the difficulty of injection molding of the prism 100, the material of the substrate 110 of the prism 100 can be selected from non-crystalline polyolefins with high transmittance and high optical quality, and the thermal expansion coefficient CTE1 of the substrate 110 is about 80E-6 / °C. After the substrate 110 is injection molded, the flatness PV1 of the surface of the substrate 110 is approximately 1um. When forming the first stacked structure 120a, firstly, a filling layer 121 with a thickness of about 200um is spin-coated on the surface of the substrate 110 where the hypotenuse of the substrate 110 is located, and then the filling layer 121 is embossed with a mold with good flatness, and then cured and demolded, so that the thickness of the final filling layer 121 is approximately 100um, and at this time, the flatness PV2 of the surface of the side of the filling layer 121 away from the substrate 110 can meet the use requirements. Finally, a film layer 122 is plated on the side of the filling layer 121 facing away from the substrate 110 .

[0075] Figure 3 This is a schematic diagram of the structure of another optical path turning element 100 provided in an embodiment of the present application. Figure 3 As shown, in this embodiment, the optical path turning element 100 can also be a right-angle prism, and the surfaces where the two right-angle sides of the prism 100 are located are respectively used as the incident surface 101 and the exit surface 102, and the surface where the hypotenuse is located is used as the reflection surface 103. Different from the above-mentioned embodiment, in this embodiment, in addition to the first stacked structure 120a of the reflection surface 103, the incident surface 101 and the exit surface 102 can also include the above-mentioned stacked structures respectively, and 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 above-mentioned embodiment, it can be known that the film layers of the second stacked structure 120b and the third stacked structure 120c are both transmissive films, so that the light passes through the second stacked structure 120b to enter the prism 100, and the light reflected by the reflection surface 103 in the prism 100 is emitted through the third stacked structure 120c.

[0076] 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.

[0077] 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. Figure 4A schematic diagram of a cross-sectional structure of another optical path turning element 100 provided in an embodiment of the present application. Figure 4 As shown, in this embodiment, the light path turning element 100 can also be a right-angle prism, or the light path turning element 100 can be regarded as Figure 2 The light path turning element 100 shown in FIG. is rotated 180°. The hypotenuse of the prism 100 is located on a reflective surface 103, and the reflective surface 103 of the prism includes a first stacked structure 120a, and the film layer 122 of the first stacked structure 120a is a reflective layer.

[0078] exist Figure 4 In the prism 100 shown, the 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 to realize the turning. Therefore, this embodiment does not require the refractive index of the filling layer 121 and the substrate 110 of the first stacked structure 120a. Exemplarily, the material of the substrate 110 can be plastic. After the substrate 110 is injection molded, a filling layer 121 with a thickness of about 200um is spin-coated on the surface of the substrate 110 where the hypotenuse of the substrate 110 is located, and then the filling layer 121 is embossed with a mold with good flatness, and then cured and demolded, so that the flatness PV of the surface of the side of the filling layer 121 away from the substrate 110 can meet the use requirements, and the thickness of the filling layer 121 finally formed can be approximately 100um. Finally, a film layer (reflective film) 122 is plated on the side of the filling layer 121 away from the substrate 110.

[0079] 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 a reflective or transmissive function, 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.

[0080] In some other possible embodiments of the present application, at least one of the other two surfaces of the prism other than the reflective surface may be a surface with optical power. That is, the prism has at least one non-planar surface, which may be either a convex surface or a concave surface, and the present application does not limit this. The following examples illustrate several prisms including surfaces with optical power.

[0081] refer to Figure 5a to Figure 5h As shown, Figure 5a to Figure 5hSeveral possible cross-sectional structural schematic diagrams of the prism 100 are shown, wherein each prism 100 may include an incident surface 101, an exit surface 102, and a reflective surface 103, and the reflective surface 103 of the prism 100 includes a laminated structure, while the incident surface 101 and the exit surface 102 of the prism 100 do not include a laminated structure. The laminated structure of the reflective surface 103 of the 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.

[0082] For example, in Figure 5a In the embodiment shown, the incident surface 101 of the prism 100 is a convex surface, and the exit surface 102 is a flat surface; Figure 5b In the embodiment shown, the incident surface 101 of the prism 100 is a concave surface, and the exit surface 102 is a flat surface; Figure 5c In the embodiment shown, the incident surface 101 of the prism 100 is a plane, and the exit surface 102 is a convex surface; Figure 5d In the embodiment shown, the incident surface 101 of the prism 100 is a plane, and the exit surface 102 is a concave surface; Figure 5e In the embodiment shown, the incident surface 101 of the prism 100 is a convex surface, and the exit surface 102 is a concave surface; Figure 5f In the embodiment shown, the incident surface 101 of the prism 100 is a concave surface, and the exit surface 102 is a convex surface; Figure 5g In the embodiment shown, both the incident surface 101 and the exit surface 102 of the prism 100 are convex surfaces; Figure 5h In the illustrated embodiment, both the incident surface 101 and the exit surface 102 of the prism 100 are concave surfaces.

[0083] The prisms 100 provided in the above examples are all capable of causing internal reflection of light 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 emitting 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.

[0084] In addition, in order to ensure that the light has good transmittance when propagating in the prism 100, and to reduce the difficulty of injection molding of the prism 100, the material of the substrate 110 of the prism 100 can be selected from non-crystalline polyolefins with high transmittance and high optical quality, and the thermal expansion coefficient CTE1 of the substrate 110 is about 80E-6 / °C. After the substrate 110 is injection molded, the flatness PV1 of the surface of the substrate 110 is approximately 1um. When forming the first stacked structure 120a, first, a filling layer 121 with a thickness of about 200um is spin-coated on the surface of the substrate 110 where the hypotenuse of the substrate 110 is located, and then the filling layer 121 is embossed with a mold with good flatness, and then cured and demolded, so that the flatness PV of the surface of the side of the filling layer 121 away from the substrate 110 can meet the use requirements, and the thickness of the filling layer 121 finally formed can be approximately 100um. Finally, a film layer (reflective film) 122 is coated on the side of the filling layer 121 facing away from the substrate 110 .

[0085] Figure 6 This is a schematic diagram of a partial structure of an electronic device 1 provided in an embodiment of the present application, wherein the partial structure of the electronic device 1 including a camera module is shown. Figure 6 As shown, 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, a vehicle-mounted device, a wearable device, augmented reality (AR) glasses, an AR helmet, virtual reality (VR) glasses or a VR helmet, or other forms of devices with photo and video functions.

[0086] The electronic device 1 includes a housing 1100 and a camera module 1200 disposed in the housing 1100. The housing 1100 is provided with a light inlet 1110, and the light inlet 1110 can connect the inside of the electronic device to the outside of the electronic device. The camera module 1200 is used to collect ambient light entering the inside of the electronic device through the light inlet 1110.

[0087] 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-incoming side and a light-outgoing side. The light-incoming side of the optical system 1210 is arranged toward the light-incoming hole 1110, and the light-outgoing side is arranged toward the circuit board 1220. The photosensitive chip 1230 is arranged on the side of the circuit board 1220 facing 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 turning element 100. The optical path turning element 100 may be used to turn the light entering the electronic device from the light-incoming hole 1110 to the lens 1211. The lens 1211 is used to project the light to the photosensitive chip 1230 located on the imaging surface of the optical system 1210, so that the photosensitive chip 1230 collects the light on the light-outgoing side of the optical system 1210 and generates a signal.

[0088] In this embodiment, the optical path turning element 100 can adopt the aforementioned Figure 2 to Figure 5h The prism in any embodiment. In a specific implementation, the camera module may further include a mounting base 1240, on which the prism 100 may be disposed, so that the mounting base 1240 is used to fix the prism 100 inside the electronic device. The incident surface 101 of the prism 100 is disposed toward the light inlet 1110, and the exit surface 102 is disposed 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 reflection surface 103 of the prism 100. At this time, the light propagating along the x-axis direction is reflected to propagate along the y-axis direction. Finally, the light is emitted toward the lens 1211 outside the prism 100 through the exit surface 102 of the prism 100.

[0089] It can be understood that the light propagating along the x-axis direction is redirected to propagate along the y-axis direction by using the optical path turning element 100. With this design, the components of the camera module 1200 can be changed 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 arranged on the back side of the housing 1100. Therefore, the above-mentioned x-direction can be understood as the thickness direction of the electronic device 1. At this time, the y-direction can be the width direction of the electronic device 1 or the length direction of the electronic device 1. Compared with the thickness direction, the size of the electronic device 1 in the width direction or the length direction is larger. 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.

[0090] Figure 7 This is a schematic diagram of the structure of another optical path turning element 100 provided in an embodiment of the present application. Figure 7As shown, in the embodiment of the present application, the optical path turning element 100 can be a multi-faceted rotating mirror. It should be noted that the number of the multi-faceted rotating mirror below is the same as the number of the optical path turning element 100. The multi-faceted rotating mirror 100 is provided with a plurality of reflecting surfaces 103 in the circumferential direction, and there is a certain angle between two adjacent reflecting surfaces 103. For example, in the present embodiment, the multi-faceted rotating mirror 100 includes four reflecting surfaces 103, and the angle between any two adjacent reflecting surfaces 103 in the circumferential direction is about 90°. Each reflecting surface 103 of the multi-faceted rotating mirror 100 includes the aforementioned Figure 1 The stacked structure shown in the figure, and the film layers of each stacked structure are reflective films.

[0091] exist Figure 7 In the illustrated embodiment, each reflecting surface 103 of the polygonal mirror 100 can reflect light outwards, and the light does not enter the interior of the polygonal mirror 100. Therefore, this embodiment does not require the refractive index of the filling layer and the substrate of the laminated structure on each reflecting surface 103. In this embodiment, the substrate material of the polygonal mirror 100 can be PMMA, which has a low cost and high molding characteristics, and its thermal expansion coefficient CTE1 is about 80E-6 / °C. After the substrate is injection molded, the flatness PV1 of the substrate surface is approximately 10um. When forming each laminated structure, first, a filling layer with a thickness of about 400um is spin-coated on each substrate surface on the periphery of the substrate, and then the filling layer is embossed with a mold with good flatness, and then cured and demolded, so that the flatness PV2 of the surface of the filling layer on the side away from the substrate can meet the use requirements. Finally, a reflective film is plated on the side of the filling layer away from the substrate.

[0092] Figure 8 This is a schematic diagram of the structure of another electronic device 2 provided in an embodiment of the present application. Figure 8 As shown, the electronic device 2 in this embodiment is described by taking a laser radar as an example. The electronic device 2 includes a housing 2100 and an optical system 2200 disposed in the housing 2100. The housing 2100 may be partially or entirely made of a light-transmitting material so that the optical system 2200 can transmit light to the external space through the housing 2100 or receive light from the external space.

[0093] The optical system 2200 may include a transmitter 2210, a receiver 2220, and an optical path turning element 100. The optical path turning element 100 may be used to reflect the light (such as pulsed laser) emitted by the transmitter 2210 to the external space. When the light detects a target object (such as a road, a pedestrian, a vehicle, etc.), it will be reflected. The optical path turning element 100 may reflect the light reflected back by the target object to the receiver 2220 again, so that the electronic device 2 can detect the road condition or environment according to the received light.

[0094] In this embodiment, the optical path turning element 100 can adopt the aforementioned Figure 6 The polygonal mirror 100 is rotatably disposed in the optical system 2200. In one implementation, the optical system 2200 may further include a driving motor (not shown in the figure), which may be used to drive the polygonal mirror 100 to rotate around its axis. The transmitter 2210 and the receiver 2220 may be located on both sides of the polygonal mirror 100, respectively. When the driving motor drives the polygonal mirror 100 to rotate, the incident angle of the light emitted by the transmitter 2210 to one of the reflecting surfaces of the polygonal mirror 100 will change, so that the exit angle of the light reflected by the reflecting surface to the external space will also change accordingly, so that the external space can be scanned within a certain angle range; accordingly, the receiver 2220 can also receive the light within a certain angle range reflected by other reflecting surfaces.

[0095] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope 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 deflection 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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