Curved compound eye lens and manufacturing method and manufacturing mold thereof

Abstract

The present application relates to the technical field of micro-machining, and particularly relates to a curved surface compound eye lens, a manufacturing method thereof and a manufacturing mold, the manufacturing method comprising the following steps: S10, establishing a three-dimensional model of a plane lens containing multiple sub-eyes; S20, printing the three-dimensional model of the plane lens by using a 3D printing technology; S30, after uniformly covering a smooth layer on the surface of the three-dimensional model of the plane lens, performing silanization treatment to obtain a master mold; S40, performing mold turning treatment on the master mold to obtain a flexible negative mold replicating the morphology of the master mold; S50, making the flexible negative mold form a curved surface cavity through negative pressure molding, injecting photosensitive resin into the curved surface cavity, and performing ultraviolet curing. The present application can manufacture a microlens array with a high-order aspheric surface profile in combination with a 3D printing technology, and effectively makes up for the shortcomings of high surface roughness and insufficient precision of a 3D printing element through the design of the smooth layer, so that the replicated lens has excellent optical performance.

Description

Technical Field

[0001] This invention belongs to the field of micromachining technology, and particularly relates to a curved compound eye lens, its manufacturing method, and manufacturing mold. Background Technology

[0002] Artificial compound eye lenses, as biomimetic optical components, mimic the structure of insect compound eyes. They integrate multiple tiny lens units onto a substrate, possessing advantages such as sensitivity to moving objects, a wide field of view, and strong anti-interference capabilities, demonstrating enormous application potential in various fields. In the medical field, novel endoscopes designed based on the principle of artificial compound eye lenses, with their wide field of view, can provide doctors with a broader field of vision, thus enabling more accurate observation of internal tissues. In the consumer electronics field, artificial compound eye lenses can improve optical imaging quality in virtual reality and augmented reality devices, providing users with a more immersive experience. In the field of drone obstacle avoidance, the core benefit of artificial compound eye lenses lies in providing drones with ultra-wide-angle, high-speed, and low-power visual perception capabilities, thereby greatly improving the efficiency and reliability of obstacle avoidance in complex and dynamic environments.

[0003] To achieve the fabrication of small aspherical compound eyes, researchers have proposed various processing methods, with the mainstream processing techniques including: 1. Femtosecond laser etching process: First, a femtosecond laser is focused onto the surface of a substrate such as quartz or silicon wafer to etch concave microlens array pits; then, a chemical solution is used for light etching to optimize the smoothness of the pits; finally, PDMS (polydimethylsiloxane) is poured into the pits, cured, and then demolded to obtain the compound eye array. This method has high precision, but involves many steps and has high laser equipment costs, making it suitable for small-batch preparation in the laboratory.

[0004] 2. Hot-press molding process: This method replicates the structure under high temperature and pressure by first creating a metal or ceramic master mold with a microlens array; then heating thermoplastic materials such as polycarbonate or optical resin to a softened state, applying pressure to the master mold to make the material conform to the pattern of the master mold; after cooling, the material is demolded to directly obtain the compound eye lens. This method is suitable for mass production and is less expensive than laser processing, but the master mold is more difficult to manufacture, and the high temperature may cause a decrease in the optical properties of the material.

[0005] 3. Photoresist thermal melting process: First, photoresist is coated on the substrate, and then the photoresist layer is etched into a cylindrical array using photolithography. The substrate is then placed on a heating stage. Upon heating, the photoresist contracts due to surface tension, naturally forming hemispherical or aspherical surfaces at the top of the cylinders. After cooling, the compound eye is fabricated. This method has low equipment requirements, but the microlens focal length adjustment range is narrow and the photoresist layer has poor temperature resistance.

[0006] It is evident that the above methods all have numerous problems and limitations in the process of preparing compound eye lenses.

[0007] As the demand for "small size, high image quality, and low cost" in miniature optical devices intensifies, existing processes are no longer sufficient to meet the needs of technological breakthroughs. Therefore, developing a simplified, low-cost, mass-producible fabrication process for small aspherical compound eyes that balances precision and material compatibility is of great significance.

[0008] With the development of 3D printing technology, its advantages in manufacturing complex three-dimensional structures are becoming increasingly prominent. However, current mainstream optical 3D printing technology, limited by factors such as materials, printing resolution, and surface roughness, often fails to achieve the precision and surface quality requirements of traditional optical processing, especially for aspherical optical surfaces. How to combine the flexible forming advantages of 3D printing with the high precision and high-quality surfaces required by traditional optical devices to achieve efficient and low-cost fabrication of complex aspherical compound eye lenses remains a current technical challenge. Summary of the Invention

[0009] In view of this, the present invention aims to provide a curved compound eye lens and its manufacturing method and mold, which utilizes the advantages of 3D printing technology to flexibly manufacture complex surface structure parts, combined with fine surface post-processing and mold making technology, to achieve low-cost, high-efficiency and high-precision manufacturing of optical-grade small aspherical compound eye lenses.

[0010] To achieve the above objectives, the technical solution created by this invention is implemented as follows: In a first aspect, the present invention provides a method for manufacturing a curved compound eye lens, comprising the following steps: S10. Establish a three-dimensional model of a planar lens containing multiple sub-eyes; S20. Use 3D printing technology to print the three-dimensional model of the planar lens; S30. After uniformly covering the surface of the three-dimensional model of the planar lens with a smoothing layer, a silanization process is performed to obtain the master mold. S40. Perform a mold-making process on the master mold to obtain a flexible negative mold that replicates the shape of the master mold; S50. The flexible negative mold is formed into a curved cavity by negative pressure molding, and photosensitive resin is injected into the curved cavity and then cured with ultraviolet light.

[0011] Furthermore, step S10 includes: obtaining the structural parameters of each sub-eye through Zemax optical simulation, constructing a three-dimensional model file in SolidWorks according to the structural parameters and importing it into Zemax, verifying it through ray tracing in non-sequential mode, and ensuring that the focus of all the sub-eyes can fall uniformly on the detector of the 3D printing technology on the same plane.

[0012] Furthermore, in step S20, the sub-eye consists of a cylindrical base and an aspherical crown disposed on the top of the cylindrical base.

[0013] Furthermore, the smoothing layer is a photoresist layer; step S30 includes: spraying a layer of photoresist onto the surface of the master mold, leveling it, and then drying it so that the photoresist uniformly covers the surface of the master mold.

[0014] Furthermore, step S40 includes: Prepare the PDMS prepolymer solution and perform the first vacuum degassing; The master mold is placed into a mold customized to its size, and the PDMS prepolymer liquid is also poured into the mold; The PDMS prepolymer liquid inside the mold is subjected to a second vacuum degassing process to remove air bubbles generated between the particles during the pouring process.

[0015] Secondly, the present invention provides a curved compound eye lens, comprising a lens body and a plurality of aspherical sub-eye lenses integrated on the lens body; the plurality of aspherical sub-eye lenses include a first-order aspherical sub-eye lens located at the top center of the lens body, and second to N-order aspherical sub-eye lenses arranged symmetrically in a ring around the first-order aspherical sub-eye lens and extending outward; the aperture and aspherical coefficient of the aspherical sub-eye lenses vary with the order, wherein N is a natural number greater than 2 and less than 6.

[0016] Furthermore, the aspherical sub-eye lens comprises a cylindrical base lens and an aspherical crown disposed on top of the cylindrical base lens, the aspherical crown lens satisfying the formula:

[0017] in, Let s be the sagitta of the surface along the optical axis at height s; This is the radial coordinate, i.e., the vertical distance from the optical axis; The curvature is the vertex curvature, that is, the curvature of the curved portion of the surface; The conic constant determines the basic conic surface type of the surface. The even-order surface coefficients are used to describe the deviation of a surface from the underlying conical surface.

[0018] Thirdly, the present invention provides a mold for manufacturing a curved compound eye lens, including a master mold, the master mold including a three-dimensional model of a planar lens containing multiple sub-eyes printed using 3D printing technology, a smoothing layer disposed on the three-dimensional model of the planar lens, and a release layer formed by silanization treatment.

[0019] Furthermore, it also includes a flexible negative mold that replicates the shape of the master mold and a molding mold with a smooth curved surface; wherein, the flexible negative mold can adhere to the smooth curved surface of the molding mold by negative pressure adsorption, so that the flexible negative mold can form a curved cavity for accommodating photosensitive resin.

[0020] Furthermore, the smoothing layer is a photoresist layer and the thickness of the photoresist layer is less than 3µm.

[0021] Compared with the prior art, the present invention can achieve the following beneficial effects: (1) The present invention adopts a step-by-step strategy of “printing a planar mold first and then smoothing it, followed by negative pressure curved surface forming” instead of directly printing a curved surface mold. This allows the photoresist to be subjected only to vertically downward gravity and uniform surface tension, spontaneously forming a smooth layer with uniform thickness and height.

[0022] (2) The method for fabricating the curved compound eye lens described in this invention, combined with 3D printing technology, can flexibly and quickly manufacture microlens arrays with high-order aspherical profiles that are difficult to achieve with traditional micro-nano processing, greatly expanding the freedom of optical design.

[0023] (3) The present invention creates a composite structure of “cylindrical base plus aspherical top crown” for the sub-eye. The significance of this configuration is to optimize the flow field of the subsequent post-processing: when the photoresist is sprayed and leveled, the cylindrical base can act as a physical isolation zone, inducing excess photoresist to accumulate in the gap between the cylindrical bases under the action of surface tension, without covering or changing the aspherical optical morphology of the top due to the droplet accumulation effect.

[0024] (4) The method for manufacturing the curved compound eye lens described in this invention and the mold manufacturing process, such as photoresist spraying to form a smooth layer on the three-dimensional model of the planar lens, effectively make up for the shortcomings of high surface roughness and insufficient precision of 3D printed components, so that the surface reaches the smoothness required by optical devices, and ensure that the replicated lens has excellent optical performance.

[0025] (5) The method for manufacturing the curved compound eye lens described in this invention and the mold manufacturing process, which combines 3D printing elements with mold making process, can accurately replicate the optical surface structure on the mold, and then achieve low-cost, large-scale mass production of small aspherical compound eye lenses by subsequent injection molding and curing of optical materials. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic flowchart illustrating the method for manufacturing a curved compound eye lens according to an embodiment of the present invention.

[0027] Figure 2 A cross-sectional view of the three-dimensional model of the planar lens described in the embodiment of the present invention.

[0028] Figure 3 A cross-sectional view of a three-dimensional model of a planar lens with a smoothing layer as described in an embodiment of the present invention.

[0029] Figure 4 This is a schematic diagram of a flexible negative mold that replicates the shape of the master mold by performing a mold-making process, as described in an embodiment of the present invention.

[0030] Figure 5 A schematic diagram of a flexible negative mold for forming a curved cavity by negative pressure molding, which is an embodiment of the present invention.

[0031] Figure 6 This is a schematic diagram of the structure of a curved compound eye lens according to an embodiment of the present invention.

[0032] Figure 7 A cross-sectional view of a curved compound eye lens according to an embodiment of the present invention.

[0033] Figure 8 This is a ray tracing diagram of a curved compound eye lens according to an embodiment of the present invention.

[0034] Explanation of reference numerals in the attached figures: 10. Master mold; 11. 3D model of planar lens; 12. Smooth layer; 20. Flexible negative mold; 21. Curved cavity; 30. Curved compound eye lens; 31. Lens body; 32. Aspherical sub-eye lens; 41. First-order aspherical sub-eye lens; 42. Second-order aspherical sub-eye lens; 43. Third-order aspherical sub-eye lens; 44. Fourth-order aspherical sub-eye lens. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and do not constitute a limitation thereof. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the invention. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the invention are not shown or described in the specification. This is to avoid obscuring the core parts of the invention with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined to form various implementations. Furthermore, the order of the steps or actions in the method description can be changed or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various orders in the specification and drawings are merely for the clear description of a particular embodiment and do not imply a mandatory order, unless otherwise stated that a particular order must be followed.

[0037] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. The term "based on" should be understood as "at least partially based on." Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more, and the term "including" means "including but not limited to." Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range; for example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] Example 1 like Figure 1 As shown, the present invention provides a method for manufacturing a curved compound eye lens, comprising the following steps: S10. Establish a three-dimensional model of a planar lens containing multiple sub-eyes; The aforementioned 3D model of the planar lens was established based on optical design requirements. More specifically, the structural parameters of each sub-eye were obtained through Zemax optical simulation. A 3D model file was then constructed in SolidWorks according to these parameters and imported into Zemax. Verification was performed using ray tracing in non-sequential mode to ensure that the focal points of all sub-eyes could fall uniformly on the same planar detector. Each sub-eye consists of a cylindrical base and an aspherical crown atop the cylindrical base. Generally, the top of the cylindrical base and the bottom of the aspherical crown have the same shape and size, ensuring a smooth transition and matching of the top contour of the cylindrical base with the bottom contour of the aspherical crown.

[0041] In this embodiment, the aforementioned sub-eye includes a first-level aspherical sub-eye, and second to N levels of aspherical sub-eyes arranged symmetrically in a ring around the first-level aspherical sub-eye and extending outwards; wherein N is a natural number greater than 2 and less than 6. Preferably, N is 4.

[0042] The primary aspherical sub-eye is located at the center of the top of the main body and there is only one. Multiple levels of aspherical sub-eyes are symmetrically distributed in concentric rings around the primary sub-eye, and the aperture of each sub-eye (i.e., the diameter of the cylindrical base) increases progressively with the level. In other words, the primary aspherical sub-eye has the smallest aperture; the larger the level, the larger the aperture. Furthermore, the height of the aspherical sub-eye (i.e., the height of the cylindrical base) also increases progressively with the level. Thus, through spatial partitioning, the primary aspherical sub-eye can focus at high resolution, while the outer second to N-level aspherical sub-eyes are used to extend the field of view, and symmetry is utilized to achieve efficient, uniform, and stable imaging.

[0043] At this point, when designing the structural parameters of the sub-eye, the aspherical coefficient in the aspherical surface formula can be adjusted through Zemax simulation to optimize the size of the RMS radius (an indicator of optical imaging quality) of the first-order aspherical sub-eye, thereby improving the optical imaging quality.

[0044] The surface shape formula for the aspherical crown of the sub-eye is as follows:

[0045] in, Let s be the sagitta of the surface along the optical axis at height s; This is the radial coordinate, i.e., the vertical distance from the optical axis; The curvature is the vertex curvature, that is, the curvature of the curved portion of the surface; The conic constant determines the basic conic surface type of the surface. The even-order surface coefficients are used to describe the deviation of a surface from the underlying conical surface.

[0046] The surface in the above formula refers to the surface of the aspherical top cap; the vertical distance from the optical axis represents the vertical distance from a point on the aspherical sub-eye lens to the optical axis.

[0047] Using the first-order aspherical eye as a benchmark, the aperture size of the second to Nth-order aspherical eyes is adjusted, and the simulation effect of ray tracing in non-sequential mode is combined to ensure that the focal point of each order of aspherical eyes falls on the same plane so that the signal can be received by the CMOS sensor in practical applications.

[0048] Based on the simulation parameters in Zemax, a three-dimensional model of a planar lens containing aspherical sub-eyes of various levels was built in SolidWorks.

[0049] S20, Using 3D printing technology to print such as Figure 2 The three-dimensional model of the planar lens shown is 11; The 3D printing technology used is photopolymer 3D printing, with a printing accuracy of 5μm layer thickness. Since 3D printing is done layer by layer, a structure can be seen as being made up of many layers of printing material stacked together. Each layer forms a step-like microstructure. The smaller these steps are, the better. Therefore, this application selects 5μm as a relatively high-precision printing parameter. Of course, within the accuracy range of the 3D printer, a layer thickness of less than 5μm is also acceptable.

[0050] In this embodiment, the printing material selected is a high-precision photosensitive resin, such as PR-SY-05. When selecting printing materials, it is necessary to consider whether there are problems such as severe structural shrinkage after printing, making it impossible to maintain the design morphology well. Molds printed with PR-SY-05 can maintain the designed surface morphology well.

[0051] The printed planar lens 3D model 11 consists of a horizontal substrate and multiple sub-eyes disposed on the horizontal substrate. The core logic of using a printed planar master mold lies in controlling the force balance during the leveling process of the smooth layer (photoresist) in the subsequent step S30: On a horizontal substrate, the photoresist is only subjected to vertically downward gravity and uniform surface tension, which can spontaneously form a smooth layer with uniform thickness and height; in contrast, if spraying is performed on a curved mold, the photoresist will inevitably flow tangentially along the curvature gradient, resulting in extremely uneven distribution of liquid film thickness on the surface of the sub-eyes.

[0052] S30. After uniformly covering the surface of the three-dimensional model of the planar lens with a smoothing layer, a silanization process is performed to obtain the master model. like Figure 3As shown, in this embodiment, the smoothing layer 12 is a photoresist layer. The material of the smoothing layer needs to have low viscosity, moderate surface tension, and good smoothness. Therefore, after experimental verification, photoresist was selected as the smoothing layer material. In addition, during the leveling process of spraying photoresist, the cylindrical base of the sub-eye can act as a physical isolation area, inducing excess photoresist to accumulate in the gaps between the cylindrical bases under the action of surface tension, without covering or changing the aspherical optical morphology of the top due to the droplet accumulation effect.

[0053] The implementation of step S30 specifically includes the following steps S31 and S32: S31. Spray a layer of AZ5214 photoresist onto the surface of the three-dimensional model of the planar lens, control the thickness of the photoresist to within 3µm, level it and dry it, so that the photoresist can uniformly cover the surface of the master mold, thereby significantly improving the surface smoothness without changing the surface shape of the three-dimensional model of the planar lens. S32. Place the three-dimensional model of the planar lens with a smooth layer into an oven and silanize it at 60°C for 2 hours.

[0054] This step involves surface treatment of the 3D-printed planar lens model to significantly reduce surface roughness and improve the shape accuracy of the aspherical profile, enabling the resulting master mold to achieve optical-grade surface quality.

[0055] S40. Perform a mold-making process on the master mold to obtain a flexible negative mold that replicates the shape of the master mold; Please refer to the following at the same time Figure 4 In practice, PDMS (polydimethylsiloxane) prepolymer solution is first prepared and vacuum degassing is performed for the first time to remove air bubbles inside the PDMS prepolymer solution. Then, the master mold is placed into a mold customized according to its size, and the PDMS prepolymer solution is also poured into the mold. Then, the PDMS prepolymer solution in the mold is vacuum degassed for the second time to remove air bubbles generated between the particles during the pouring process. Finally, the mold is placed in an oven to dry for 5 hours, and the dried mold is demolded to obtain a flexible negative mold 20 that replicates the morphology of the master mold 10, i.e., the PDMS film.

[0056] S50. A flexible negative mold is formed into a curved cavity by negative pressure molding, and photosensitive resin is injected into the curved cavity and then cured with ultraviolet light.

[0057] Please refer to the following at the same time Figure 5The flexible negative mold 20 is adhered to a smooth curved surface with a preset curvature on the molding mold by negative pressure adsorption, thereby forming a curved cavity 21 for accommodating the photosensitive resin. NOA63 photosensitive resin is poured into the curved cavity 21, and the cavity filled with photosensitive resin is cured with a UV curing lamp for 3 minutes. After curing, the mold is removed to obtain the desired product. Figure 6 The curved compound eye lens shown.

[0058] This embodiment enables the fabrication of lenses with complex surface shapes, offering greater freedom, lower cost, and higher production efficiency compared to traditional methods. Furthermore, the curved compound eye lens fabricated using this method allows for greater freedom in surface design, effectively reducing spherical aberration. Compared to spherical microlenses of the same size with only one curvature parameter, which struggle to simultaneously correct spherical aberration, this method produces superior imaging results.

[0059] Example 2 like Figures 5 to 8 As shown, the present invention provides a curved compound eye lens 30, including a lens body 31 and a plurality of aspherical sub-eye lenses 32 integrated on the lens body 31. The lens body 31 is a curved surface structure with a preset curvature to adapt to the imaging requirements of a large field of view. The plurality of aspherical sub-eye lenses 32 includes a first-order aspherical sub-eye lens 41 located at the top center of the lens body, and second to N-order aspherical sub-eye lenses symmetrically arranged in a ring extending outward from the first-order aspherical sub-eye lens as the center; wherein N is a natural number greater than 2 and less than 6. Preferably, N is 4. When N is four, the plurality of aspherical sub-eye lenses 32 includes a first-order aspherical lens 41, a second-order aspherical lens 42, a third-order aspherical lens 43, and a fourth-order aspherical lens 44. Among them, the first-order aspherical lens 41 is located at the top center of the lens body 31 and there is only one. The second to Nth grade aspherical lenses are arranged in a concentric ring symmetrical distribution with the first grade aspherical lens 41 as the center.

[0060] An aspherical sub-eye lens consists of a cylindrical base lens and an aspherical crown lens disposed on top of the cylindrical base lens, and the cylindrical base lens and the aspherical crown lens are integrally formed. Generally, the top of the cylindrical base lens and the bottom of the aspherical crown lens have the same shape and size, so that the top contour of the cylindrical base lens matches the bottom contour of the aspherical crown lens and forms a smooth transition.

[0061] Furthermore, the aperture (diameter of the cylindrical base lens) of the aforementioned aspherical sub-lens 32 increases progressively with each order. That is, the first-order aspherical sub-lens 41 has the smallest aperture. This is because, based on the curved contour of the lens body 31, the outermost aspherical sub-lenses require a longer focal length to ensure their focus falls on the same focal plane. A larger aperture means a longer focal length, hence the progressively increasing aperture. Thus, through spatial partitioning, the first-order aspherical lens 41 can focus at high resolution, while the outer second to Nth-order aspherical lenses 42, 43, and 44 are used to expand the field of view and utilize symmetry to achieve efficient, uniform, and stable imaging. In practical implementation, the height of the aspherical lenses (i.e., the height of the cylindrical base lens) also increases progressively with each order.

[0062] More specifically, the aspherical crown lens satisfies the formula:

[0063] in, Let s be the sagitta of the surface along the optical axis at height s; This is the radial coordinate, i.e., the vertical distance from the optical axis; The curvature is the vertex curvature, that is, the curvature of the curved portion of the surface; The conic constant determines the basic conic surface type of the surface. The even-order surface coefficients are used to describe the deviation of a surface from the underlying conical surface.

[0064] The surface in the above formula refers to the surface of the aspherical crown lens in the aspherical sub-eye lens; the vertical distance from the optical axis represents the vertical distance from a point on the aspherical sub-eye lens to the optical axis.

[0065] The aforementioned curved compound eye lens was manufactured using the method for manufacturing curved compound eye lenses provided by this invention.

[0066] Example 3 This invention provides a mold for manufacturing curved compound eye lenses, including a master mold. Please also refer to... Figure 3 The master mold includes a three-dimensional model 11 of a planar lens containing multiple sub-eyes printed using 3D printing technology, a smoothing layer 12 set on the three-dimensional model of the planar lens, and a release layer (not shown in the figure) formed by silanization treatment.

[0067] The smoothing layer 12 is a photoresist layer with a thickness of less than 3µm, thereby significantly improving the surface smoothness without altering the surface profile of the planar lens 3D model. In practice, an AZ5214 photoresist layer can be sprayed onto the surface of the planar lens 3D model, with the photoresist thickness controlled within 3µm. After leveling and drying, the photoresist can uniformly cover the surface of the master mold to form the smoothing layer 12. The release layer is obtained by placing the planar lens 3D model with the smoothing layer in an oven for silanization at 60°C for 2 hours.

[0068] In this embodiment, the three-dimensional model 11 of the planar lens is established according to the optical design requirements. More specifically, the structural parameters of each sub-eye are obtained through Zemax optical simulation, and a three-dimensional model file is built in SolidWorks according to the parameters and imported into Zemax. The model is then verified by ray tracing in non-sequential mode to ensure that the focal points of all sub-eyes can fall uniformly on the same planar detector.

[0069] The aforementioned sub-eye includes a first-order aspherical sub-eye, and second to N orders of aspherical sub-eyes arranged symmetrically in a ring around the first-order aspherical sub-eye and extending outwards; where N is a natural number greater than 2 and less than 6. Preferably, N is four. Preferably, the sub-eye consists of a cylindrical base and an aspherical crown disposed on top of the cylindrical base. The diameter of the sub-eye (i.e., the diameter of the cylindrical base) increases progressively with the number of orders, and the height of the sub-eye (i.e., the height of the cylindrical base) also increases progressively with the number of orders. Generally, the top of the cylindrical base and the bottom of the aspherical crown have the same shape and size, so that the top contour of the cylindrical base matches and smoothly transitions with the bottom contour of the aspherical crown.

[0070] At this point, when designing the structural parameters of the sub-eye, the RMS radius of the first-order aspherical sub-eye can be optimized by adjusting the aspherical coefficient in the aspherical surface formula through Zemax simulation.

[0071] Using the first-level aspherical sub-eye as a benchmark, the aperture size of the second to Nth level aspherical sub-eyes is adjusted, and the simulation effect of ray tracing in non-sequential mode is combined to ensure that the focus of each level of sub-eye falls on the same plane so that the signal can be received by the CMOS sensor in practical applications.

[0072] Based on the simulation parameters in Zemax, a three-dimensional model of a planar lens containing various levels of sub-eyes was created in SolidWorks.

[0073] The 3D printing technology is photopolymer 3D printing, with a printing accuracy of 5μm layer thickness, and the selected printing material is a high-precision photosensitive resin, such as PR-SY-05.

[0074] Example 4 This invention provides a mold for manufacturing a curved compound eye lens, comprising a master mold, a flexible negative mold replicating the shape of the master mold, and a molding mold with a smooth curved surface. The flexible negative mold can be adhered to the curved surface of the molding mold by negative pressure adsorption, allowing the flexible negative mold to form a curved cavity for accommodating photosensitive resin. The smooth curved surface of the molding mold has a preset curvature. The structure of the master mold is the same as that in Embodiment 3 above, and will not be described again here.

[0075] The flexible negative mold is obtained by replicating the master mold. In this embodiment, the flexible negative mold is a PDMS film. In practice, a PDMS prepolymer solution is first prepared and subjected to a first vacuum degassing process to remove air bubbles inside the PDMS prepolymer solution; then, the master mold is placed into a mold customized to its size, and the PDMS prepolymer solution is also poured into the mold; then, the PDMS prepolymer solution in the mold is subjected to a second vacuum degassing process to remove air bubbles generated during the pouring process; finally, the mold is placed in an oven to dry for 5 hours, and the dried mold is demolded to obtain a flexible negative mold 20 that replicates the morphology of the master mold 10, i.e., the PDMS film.

[0076] This invention effectively combines the complex structure forming capabilities of 3D printing, the improved optical precision of surface post-processing, and the advantages of batch replication of mold-making technology. It realizes complex aspherical compound eye structures that are difficult to manufacture using traditional processes, significantly reducing manufacturing costs and cycles, improving the ability to achieve product customization and complex optical designs, and providing a new solution for small-volume, high-quality, and low-cost optical systems.

[0077] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0078] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for manufacturing a curved compound eye lens, characterized in that, Including the following steps: S10. Establish a three-dimensional model of a planar lens containing multiple sub-eyes, wherein each sub-eye is composed of a cylindrical base and an aspherical crown disposed on the top of the cylindrical base; S20. The planar lens three-dimensional model is printed using 3D printing technology. The planar lens three-dimensional model consists of a horizontal substrate and multiple sub-eyes disposed on the horizontal substrate. S30. After uniformly covering the surface of the three-dimensional model of the planar lens with a smoothing layer, a silanization treatment is performed to obtain the master mold. The smoothing layer is a photoresist layer. A layer of photoresist is sprayed onto the surface of the three-dimensional model of the planar lens, leveled, and dried to uniformly cover the surface of the three-dimensional model of the planar lens. The smoothness of the surface is improved without changing the surface shape of the three-dimensional model of the planar lens. When spraying the photoresist for leveling treatment, the cylindrical base of the sub-eye acts as a physical isolation area, inducing excess photoresist to accumulate in the gaps between the cylindrical bases under the action of surface tension, so as not to cover or change the aspherical optical morphology of the top due to the droplet accumulation effect. S40. Perform a mold-making process on the master mold to obtain a flexible negative mold that replicates the shape of the master mold; S50. The flexible negative mold is formed into a curved cavity by negative pressure molding, and photosensitive resin is injected into the curved cavity and then cured with ultraviolet light.

2. The method for manufacturing a curved compound eye lens according to claim 1, characterized in that: Step S10 includes: obtaining the structural parameters of each sub-eye through Zemax optical simulation, constructing a three-dimensional model file in SolidWorks according to the structural parameters and importing it into Zemax, verifying it through ray tracing in non-sequential mode, and ensuring that the focal points of all the sub-eyes can fall uniformly on the detector of the same plane.

3. The method for manufacturing a curved compound eye lens according to claim 1, characterized in that, Step S40 includes: Prepare the PDMS prepolymer solution and perform the first vacuum degassing; The master mold is placed into a mold customized to its size, and the PDMS prepolymer liquid is also poured into the mold; The PDMS prepolymer liquid inside the mold is subjected to a second vacuum degassing process to remove air bubbles generated between the particles during the pouring process.

4. A curved compound eye lens, characterized in that, The curved compound eye lens is obtained by the manufacturing method of any one of claims 1 to 3. The curved compound eye lens includes a lens body and a plurality of aspherical sub-eye lenses integrated on the lens body. The plurality of aspherical sub-eye lenses include a first-order aspherical sub-eye lens located at the top center of the lens body, and second to N-order aspherical sub-eye lenses arranged symmetrically in a ring around the first-order aspherical sub-eye lens and extending outward. The aperture and aspherical coefficient of the aspherical sub-eye lenses change with the order, where N is a natural number greater than 2 and less than 6.

5. The curved compound eye lens according to claim 4, characterized in that, The aspherical sub-eye lens consists of a cylindrical base lens and an aspherical crown lens disposed on top of the cylindrical base lens. The aspherical crown lens satisfies the following formula: in, Let s be the sagitta of the surface along the optical axis at height s; This is the radial coordinate, i.e., the vertical distance from the optical axis; The curvature is the vertex curvature, that is, the curvature of the curved portion of the surface; The conic constant determines the basic conic surface type of the surface. The even-order surface coefficients are used to describe the deviation of a surface from the underlying conical surface.

6. A mold for manufacturing a curved compound eye lens, characterized in that, The mold for manufacturing the curved compound eye lens is obtained by the method for manufacturing the curved compound eye lens according to any one of claims 1 to 3. The mold for manufacturing the curved compound eye lens includes a master mold, which includes a three-dimensional model of a planar lens containing multiple sub-eyes printed by 3D printing technology, a smoothing layer disposed on the three-dimensional model of the planar lens, and a release layer formed by silanization treatment.

7. The mold for manufacturing the curved compound eye lens according to claim 6, characterized in that, It also includes a flexible negative mold that replicates the shape of the master mold and a molding mold with a smooth curved surface; wherein, the flexible negative mold can adhere to the smooth curved surface of the molding mold by negative pressure adsorption, so that the flexible negative mold can form a curved cavity for accommodating photosensitive resin.

8. The mold for manufacturing the curved compound eye lens according to claim 6, characterized in that, The smoothing layer is a photoresist layer and the thickness of the photoresist layer is less than 3µm.

Images