An asymmetric double-sided compound eye lens array, its fabrication method and application

Abstract

This invention provides an asymmetric double-sided compound eye lens array, its fabrication method, and its application, belonging to the field of optical lens technology. By reducing the aperture of the exit lens unit, this invention lowers the processing difficulty of the mold cavity, eliminating the need for high-precision specialized processing equipment and reducing mold manufacturing costs by 40-60%. During the fabrication process, the amount of material used in injection molding is reduced, and the energy consumption for pressure holding during compression molding is lowered, further reducing production costs. With the reduced aperture, the material reduction during injection molding shortens the material filling and cooling time by 30-50%, and the pressure holding time during compression molding by 20-40%, adapting to the mass production needs of different materials and significantly improving production efficiency.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, and in particular to an asymmetric double-sided compound eye lens array, its preparation method, and its application. Background Technology

[0002] Compound eye lens arrays are widely used in various optical systems due to their excellent light-uniforming performance. Traditional double-sided compound eye lens arrays typically employ a symmetrical structure design, meaning that the lens apertures on the incident and exit surfaces are exactly the same, and both are continuously distributed full-aperture lens units. In actual production, this type of full-aperture double-sided compound eye mold has significant drawbacks: on the one hand, the processing of full-aperture lens units requires higher precision equipment and more complex processing techniques, leading to a substantial increase in mold manufacturing costs; on the other hand, during the mold forming process, the filling (injection molding) or pressurization (compression molding) of the full-aperture lens units requires a longer time, severely impacting production efficiency and failing to meet the demands of large-scale mass production.

[0003] In existing technologies, some solutions attempt to reduce the overall size of the lens array to lower costs and shorten molding time, but this leads to a decrease in optical uniformity. Other solutions employ a single-sided optimization design, but fail to asymmetrically adjust the aperture of the double-sided lenses and are only compatible with a single injection molding process, failing to meet the molding requirements of hard and brittle materials such as glass. Therefore, providing a double-sided compound eye lens array that can reduce mold costs, shorten molding time, and adapt to multiple thermoforming processes while ensuring optical uniformity has become a pressing technical problem in this field. Summary of the Invention

[0004] The purpose of this invention is to provide an asymmetric double-sided compound eye lens array, its preparation method and application. The asymmetric double-sided compound eye lens array provided by this invention has the same light uniformity as the traditional symmetric double-sided compound eye lens array, while significantly reducing mold costs, greatly improving production efficiency and yield, and is compatible with various thermoforming processes.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: The present invention provides an asymmetric double-sided compound eye lens array, comprising a substrate and an incident lens array and an exit lens array respectively disposed on both sides of the substrate; the aperture of the exit lens unit in the exit lens array is 30 to 70% of the aperture of the incident lens unit in the incident lens array.

[0006] Preferably, the asymmetric double-sided compound eye lens array is made of a polymer material or a hard and brittle material; the polymer material is optical grade acrylic or optical grade polycarbonate; the transmittance of the polymer material is ≥92%; the hard and brittle material is optical glass or optical crystal; the transmittance of the hard and brittle material is ≥90%.

[0007] Preferably, the incident lens units in the incident lens array are arranged in a regular polygonal or circular pattern; the number of incident lens units is 50 to 500; the aperture of the incident lens unit is 3 to 10 mm; and the focal length of the incident lens unit is 5 to 20 mm.

[0008] Preferably, the edge of the exit lens unit is provided with a transition chamfer of 0.1~0.5mm.

[0009] This invention provides a method for fabricating the asymmetric double-sided compound eye lens array described above, comprising the following steps: (1) Based on the light uniformity effect of the required asymmetric double-sided compound eye lens array, determine the aperture, focal length, number of lens units and arrangement of the incident lens unit in the incident lens array. Based on the thermoforming method, determine the substrate thickness and obtain the parameters of the incident lens unit. (2) Under the premise of ensuring that the total light transmission meets the requirements of the optical system, the exit lens unit in the exit lens array is designed asymmetrically to obtain the parameters of the exit lens unit; the light transmission aperture of the exit lens unit is 30~70% of the light transmission aperture of the incident lens unit in step (1); (3) The mold is processed according to the parameters of the incident lens unit obtained in step (1) and the parameters of the exit lens unit obtained in step (2) to obtain the incident mold and the exit mold. (4) The material is thermoformed in the incident surface mold and the exit surface mold obtained in step (3) to obtain an asymmetric double-sided compound eye lens array.

[0010] Preferably, in step (4), when the material is a polymer material, the thermoforming method is injection molding; the injection molding process is as follows: after melting the material, it is injected into the incident mold and the exit mold, and after cooling, an asymmetric double-sided compound eye lens array is obtained.

[0011] Preferably, the melting temperature is 200~280℃; the injection pressure is 60~100MPa; the injection time is 4~7s; and the cooling time is 8~14s.

[0012] Preferably, in step (4), when the material is a hard and brittle material, the thermoforming method is compression molding; the compression molding process is as follows: after softening the material, it is placed into the injection mold and the exit mold for compression molding.

[0013] Preferably, the softening temperature is 500~600℃; the molding pressure is 5~20MPa; and the molding time is 5~15s.

[0014] This invention provides the application of the asymmetric double-sided compound eye lens array described in the above technical solution or the asymmetric double-sided compound eye lens array prepared by the preparation method described in the above technical solution in projection display, lighting equipment or laser processing.

[0015] This invention provides an asymmetric double-sided compound eye lens array, comprising a substrate and an incident lens array and an exit lens array respectively disposed on both sides of the substrate; the aperture of the exit lens unit in the exit lens array is 30-70% of the aperture of the incident lens unit in the incident lens array. By reducing the aperture of the exit lens unit, this invention reduces the processing difficulty of the mold cavity, eliminating the need for high-precision specialized processing equipment and reducing mold manufacturing costs by 40-60%; during the manufacturing process, the amount of material used in injection molding is reduced, and the holding pressure energy consumption in compression molding is lowered, further reducing production costs; after reducing the aperture, the material reduction during injection molding can shorten the material filling and cooling time by 30-50%, and the holding pressure time during compression molding by 20-40%, and it adapts to the mass production needs of different materials, significantly improving production efficiency. This invention designs the aperture of the incident and exit lens units, ensuring a one-to-one correspondence between the exit and incident lens units. This creates a non-continuous array of small lenses on the incident and exit surfaces, guaranteeing orderly light transmission and achieving optical uniformity (≥92%) comparable to traditional full-aperture products. Results from embodiments show that the asymmetric double-sided compound eye lens array provided by this invention achieves ≥92% uniformity, reduces mold manufacturing costs by 40-60%, shortens material filling and cooling time in injection molding by 30-50%, reduces holding time in compression molding by 20-40%, and increases yield by 15-25%. Detailed Implementation

[0016] The present invention provides an asymmetric double-sided compound eye lens array, comprising a substrate and an incident lens array and an exit lens array respectively disposed on both sides of the substrate; the aperture of the exit lens unit in the exit lens array is 30 to 70% of the aperture of the incident lens unit in the incident lens array.

[0017] In this invention, the asymmetric double-sided compound eye lens array is preferably made of a polymer material or a hard and brittle material; the polymer material is preferably optical grade acrylic (PMMA) or optical grade polycarbonate (PC); the transmittance of the polymer material is preferably ≥92%; the hard and brittle material is preferably optical glass or optical crystal, more preferably K9 glass or quartz glass; the transmittance of the hard and brittle material is preferably ≥90%. By using the above materials, this invention can ensure that the obtained asymmetric double-sided compound eye lens array has excellent optical homogenization function (uniformity ≥92%).

[0018] In this invention, the thickness of the substrate is preferably 0.5~5mm. By controlling the thickness of the substrate, this invention can ensure uniform stress during the molding process.

[0019] In this invention, the arrangement of the incident lens units in the incident lens array is preferably a regular polygonal arrangement or a circular arrangement; the regular polygonal arrangement is preferably an equilateral triangle arrangement, a regular quadrilateral arrangement, a regular pentagonal arrangement, or a regular hexagonal arrangement; the number of incident lens units is preferably 50 to 500. As one embodiment of this invention, the number of incident lens units can be 64, 81, 100, 121, 144, 225, 256, 289, 324, 361, 400, 441, or 484.

[0020] In this invention, the incident lens unit is preferably structured as a spherical or aspherical surface. The aspherical structure is suitable for high-precision uniform lighting scenarios such as laser processing, while the spherical structure is suitable for low-cost lighting scenarios.

[0021] In this invention, the aperture of the incident lens unit is preferably 3-10 mm; the focal length of the incident lens unit is preferably 5-20 mm. As one embodiment of this invention, the aperture of the incident lens unit can be 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, or 9 mm; the focal length of the incident lens unit can be 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 15 mm, 16 mm, or 18 mm. This invention achieves the desired uniform light effect by controlling the parameters of the incident lens unit.

[0022] In this invention, the aperture of the exit lens unit is 30-70% of the aperture of the incident lens unit, preferably 40-60%, and more preferably 50%. The number and arrangement of the exit lens units preferably correspond one-to-one with the arrangement of the incident lens units. The focal length of the exit lens unit is preferably the same as that of the incident lens unit. By controlling the aperture of the exit lens unit, this invention allows the exit surface to form a discontinuous array of small lens units; by controlling the arrangement of the exit lens units, the continuity of light transmission can be ensured.

[0023] In this invention, the structure of the exit lens unit is preferably a spherical structure or an aspherical structure. The aspherical structure is suitable for high-precision uniform lighting scenarios such as laser processing, while the spherical structure is suitable for low-cost lighting scenarios.

[0024] In this invention, the edge of the exit lens unit preferably has a transition chamfer of 0.1~0.5mm, more preferably 0.2~0.4mm, and even more preferably 0.3mm. By providing a transition chamfer at the edge of the exit lens unit, this invention can prevent light scattering at the lens edge and enhance the stress dispersion effect during molding.

[0025] In this invention, the edge of the exit lens unit preferably includes a draft angle of 0.1~0.3mm, more preferably 0.2mm. By setting the draft angle, this invention can prevent sticking to the mold after molding, which is beneficial for better demolding.

[0026] In this invention, the surface roughness Ra of the asymmetric double-sided compound eye lens array is preferably ≤0.01μm.

[0027] This invention reduces the processing difficulty of the mold cavity by reducing the aperture of the exit lens unit, eliminating the need for high-precision special processing equipment and reducing mold manufacturing costs by 40-60%. During the preparation process, the amount of material used in injection molding is reduced, and the energy consumption for holding pressure during compression molding is lowered, further reducing production costs. With the reduced aperture, the material reduction during injection molding shortens the material filling and cooling time by 30-50%, and the holding pressure time during compression molding by 20-40%, while also adapting to the mass production needs of different materials, significantly improving production efficiency.

[0028] This invention designs the light-transmitting apertures of the incident and exit lens units and makes the arrangement of the exit lens units correspond one-to-one with that of the incident lens units. The incident and exit surfaces form a corresponding arrangement of discontinuous "small" lens arrays, which can ensure orderly light transmission and achieve the same optical uniformity function (uniformity ≥92%) as traditional full-aperture products.

[0029] This invention reduces stress concentration during molding by designing a smaller draft angle and transition chamfer in the exit lens unit, thereby improving structural stability, reducing the risk of lens cracking, and increasing the yield by 15-25%.

[0030] This invention provides a method for fabricating the asymmetric double-sided compound eye lens array described above, comprising the following steps: (1) Based on the light uniformity effect of the required asymmetric double-sided compound eye lens array, determine the aperture, focal length, number of lens units and arrangement of the incident lens unit in the incident lens array. Based on the thermoforming method, determine the substrate thickness and obtain the parameters of the incident lens unit. (2) Under the premise of ensuring that the total light transmission meets the requirements of the optical system, the exit lens unit in the exit lens array is designed asymmetrically to obtain the parameters of the exit lens unit; the light transmission aperture of the exit lens unit is 30~70% of the light transmission aperture of the incident lens unit in step (1); (3) The mold is processed according to the parameters of the incident lens unit obtained in step (1) and the parameters of the exit lens unit obtained in step (2) to obtain the incident mold and the exit mold. (4) The material is thermoformed in the incident surface mold and the exit surface mold obtained in step (3) to obtain an asymmetric double-sided compound eye lens array.

[0031] Based on the desired uniform light effect of the asymmetric double-sided compound eye lens array, this invention determines the aperture, focal length, number of lens units, and arrangement of the incident lens units in the incident lens array. Based on the thermoforming method, the substrate thickness is determined, and the parameters of the incident lens units are obtained.

[0032] This invention does not impose specific limitations on the aperture, focal length, number of lens units, and arrangement of the incident lens units. Conventional selections based on the uniform light distribution effect of the asymmetric double-sided compound eye lens array are sufficient. By determining the parameters based on the uniform light distribution effect, this invention ensures that the incident surface can efficiently receive and transmit incident light.

[0033] In this invention, the thermoforming is preferably injection molding or compression molding; the thickness of the substrate is preferably 0.5~5mm.

[0034] In this invention, when the thermoforming is injection molding, the thickness of the substrate is preferably 0.5~3mm, more preferably 1~2.5mm, and even more preferably 1.5~2mm; when the thermoforming is compression molding, the thickness of the substrate is preferably 1~5mm, more preferably 2~4mm, and even more preferably 3mm. By determining the substrate thickness according to the thermoforming method, this invention ensures uniform stress during the molding process.

[0035] After obtaining the parameters of the incident lens unit, this invention performs an asymmetric design on the exit lens unit in the exit lens array, while ensuring that the total light transmission meets the requirements of the optical system, and obtains the parameters of the exit lens unit.

[0036] In this invention, when the thermoforming is compression molding, the edge of the exit lens unit preferably has a draft angle of 0.1~0.3mm, more preferably 0.2mm. By setting the draft angle, this invention can prevent sticking to the mold after compression molding, which is beneficial for better demolding.

[0037] After obtaining the parameters of the incident lens unit and the exit lens unit, the present invention processes the mold according to the parameters of the incident lens unit and the exit lens unit respectively to obtain the incident mold and the exit mold.

[0038] In this invention, the incident surface mold is preferably machined by precision milling; the exit surface mold is preferably machined by conventional CNC milling followed by polishing. By controlling the machining method, this invention facilitates the production of molds with more precise dimensions.

[0039] In this invention, the cavity size of the ejector mold is preferably matched with the aperture of the ejector lens unit. By designing an ejector lens unit with a small aperture, this invention reduces the machining difficulty of the ejector mold, allowing it to be completed using ordinary precision machining equipment (such as CNC milling and EDM), thus reducing mold manufacturing costs.

[0040] In this invention, when the thermoforming is injection molding, the injection mold and the exit mold independently include a gate and a runner; the gate is preferably a side gate; the diameter of the gate is preferably 2-5 mm, more preferably 3-4 mm; the diameter of the runner is preferably 2-5 mm, more preferably 3-4 mm; when the thermoforming is compression molding, the injection mold and the exit mold independently include a heating module; the heating module is preferably adapted to a temperature of 200-600℃, more preferably 300-400℃. This invention does not impose any special limitations on the specific structure, size, and position of the gate and heating module; these can be determined based on the technical knowledge of those skilled in the art. This invention, by adjusting the structure of the injection mold and the exit mold according to different thermoforming methods, facilitates preparation according to different situations, and the preparation method is simple and has good universality.

[0041] After obtaining the incident surface mold and the exit surface mold, the present invention thermoforms the material in the incident surface mold and the exit surface mold to obtain an asymmetric double-sided compound eye lens array.

[0042] In this invention, the materials are preferably polymeric materials or hard and brittle materials; the polymeric materials are preferably optical grade acrylic (PMMA) or optical grade polycarbonate (PC); the transmittance of the polymeric materials is preferably ≥92%; the hard and brittle materials are preferably optical glass or optical crystals, more preferably K9 glass or quartz glass; the transmittance of the hard and brittle materials is preferably ≥90%. By using the above materials, this invention can ensure that the uniform light effect of the obtained asymmetric double-sided compound eye lens array meets the requirements.

[0043] In this invention, when the material is a polymer, the thermoforming method is preferably injection molding; the injection molding process is preferably as follows: the material is melted and injected into an incident mold and an exit mold, and after cooling, an asymmetric double-sided compound eye lens array is obtained; the melting temperature is preferably 200~280℃; the injection pressure is preferably 60~100MPa; the injection time is preferably 4~7s; and the cooling time is preferably 8~14s. As one embodiment of this invention, the melting temperature can be 210℃, 220℃, 230℃, 240℃, 250℃, 260℃, or 270℃; the injection pressure can be 65MPa, 70MPa, 75MPa, 80MPa, 85MPa, 90MPa, or 95MPa; the injection time is preferably 5~6s; and the cooling time can be 9s, 10s, 11s, 12s, or 13s. This invention uses injection molding to prepare an asymmetric double-sided compound eye lens array. Due to the small aperture of the exit lens unit, the material filling speed can be accelerated and the cooling time can be shortened by 30-50%.

[0044] In this invention, when the material is hard and brittle, the thermoforming method is preferably compression molding; the compression molding process is preferably as follows: after softening the material, it is placed into an injection mold and an exit mold for compression molding; the softening temperature is preferably 500~600℃; the compression molding pressure is preferably 5~20MPa; and the compression molding time is preferably 5~15s. As one embodiment of this invention, the softening temperature can be 510℃, 520℃, 530℃, 540℃, 550℃, 560℃, 570℃, 580℃, or 590℃; the compression molding pressure can be 6MPa, 8MPa, 10MPa, 12MPa, 14MPa, 15MPa, 16MPa, or 18MPa; and the compression molding time can be 6s, 7s, 8s, 9s, 10s, 11s, 12s, 13s, or 14s. This invention uses compression molding to prepare an asymmetric double-sided compound eye lens array. Because the light-transmitting aperture of the lens unit is small, the exit surface is "small", and the force-bearing area of ​​the lens unit is small, the holding time can be shortened by 20-40%.

[0045] The present invention preferably further includes post-processing of the asymmetric double-sided compound eye lens array; the post-processing preferably includes trimming and polishing in sequence.

[0046] The present invention does not impose any special limitations on the specific operation of the trimming. Any process known to those skilled in the art can be used to remove the injection gate or molding flash.

[0047] In this invention, the polishing is preferably physical polishing. This invention does not impose any special limitations on the specific polishing operation, as long as the surface accuracy of the asymmetric double-sided compound eye lens array meets the optical requirements.

[0048] The asymmetric double-sided compound eye lens array provided by this invention is compatible with thermoforming processes such as injection molding and compression molding, and can cover a variety of optical materials such as polymers, glass and crystals. It is suitable for different scenarios such as projection display, lighting and laser processing, and can meet the large-scale mass production needs of different materials.

[0049] This invention provides the application of the asymmetric double-sided compound eye lens array described in the above technical solution or the asymmetric double-sided compound eye lens array prepared by the preparation method described in the above technical solution in projection display, lighting equipment or laser processing.

[0050] The present invention does not impose any special limitation on the specific method of application, and can be applied in a manner known to those skilled in the art.

[0051] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0052] Example 1 An asymmetric double-sided compound eye lens array comprises a substrate and an incident lens array and an exit lens array respectively disposed on both sides of the substrate. The asymmetric double-sided compound eye lens array is made of optical-grade acrylic with a transmittance of ≥92%. The thickness of the substrate is 1 mm; The incident lens array is arranged in a regular quadrilateral pattern, and the number of incident lens units is 100 (10×10). Both the incident lens unit and the exit lens unit have spherical structures. The incident lens unit has a light-transmitting aperture of 5mm and a focal length of 10mm; the exit lens unit has a light-transmitting aperture of 50% (2.5mm) of the incident lens unit; the number and arrangement of the exit lens units correspond one-to-one with the arrangement of the incident lens units; the focal length of the exit lens unit is the same as that of the incident lens unit. The edge of the exit lens unit is provided with a 0.2mm transition chamfer; The surface roughness Ra of the asymmetric double-sided compound eye lens array is 0.008 μm; The method for preparing the asymmetric double-sided compound eye lens array comprises the following steps: (1) Based on the requirement that the uniformity of light in the asymmetric double-sided compound eye lens array is 95%, the aperture of the incident lens unit in the incident lens array is determined to be 5mm, the focal length is 10mm, the number of lens units is 100, and the arrangement is a regular quadrilateral arrangement. The thickness of the substrate is determined to be 1mm by injection molding, and the parameters of the incident lens unit are obtained. (2) Under the premise of ensuring that the total light transmission meets the requirements of the optical system, the exit lens unit in the exit lens array is designed asymmetrically. The light transmission aperture of the exit lens unit is 50% (2.5mm) of the light transmission aperture of the incident lens unit, and the parameters of the exit lens unit are obtained (other parameters are the same as those of the incident lens array). (3) Based on the parameters of the incident lens unit obtained in step (1) and the parameters of the exit lens unit obtained in step (2), the incident mold is precision milled and polished after ordinary CNC milling to obtain the exit mold; the cavity size of the exit mold matches the light transmission aperture of the exit lens unit; both the incident mold and the exit mold are provided with a side gate and runner with a diameter of 3mm; (4) After the material is melted, it is injected into the injection mold and the exit mold obtained in step (3). After cooling, the injection gate is removed, and then the surface roughness Ra is physically polished to 0.008 μm to obtain an asymmetric double-sided compound eye lens array. The melting temperature is 220℃, the injection pressure is 80 MPa, the injection time is 5 s, and the cooling time is 10 s.

[0053] Comparative Example 1 A symmetrical double-sided compound eye lens array comprises a substrate and an incident lens array and an exit lens array respectively disposed on both sides of the substrate. The symmetrical double-sided compound eye lens array is made of optical-grade acrylic with a transmittance of ≥92%. The thickness of the substrate is 1 mm; The incident lens array is arranged in a regular quadrilateral pattern, and the number of incident lens units is 100 (10×10). Both the incident lens unit and the exit lens unit have spherical structures. The incident lens unit and the exit lens unit both have a light transmission aperture of 5mm and a focal length of 10mm; the number and arrangement of the exit lens units correspond one-to-one with the arrangement of the incident lens units; the focal length of the exit lens units is the same as that of the incident lens units. The edge of the exit lens unit is provided with a 0.2mm transition chamfer; The surface roughness Ra of the symmetrical double-sided compound eye lens array is 0.008 μm; The method for preparing the symmetrical double-sided compound eye lens array comprises the following steps: (1) Based on the requirement that the uniformity of light in the symmetrical double-sided compound eye lens array is 95%, the aperture of the incident lens unit in the incident lens array is determined to be 5mm, the focal length is 10mm, the number of lens units is 100, and the arrangement is a regular quadrilateral arrangement. The thickness of the substrate is determined to be 1mm by injection molding, and the parameters of the incident lens unit are obtained. (2) Under the premise of ensuring that the total light transmission meets the requirements of the optical system, the exit lens unit in the exit lens array is symmetrically designed, and the parameters of the exit lens unit are the same as those of the incident lens array. (3) Based on the parameters of the incident lens unit obtained in step (1) and the parameters of the exit lens unit obtained in step (2), the incident mold and the exit mold are precision milled; both the incident mold and the exit mold are provided with side gates and runners with a diameter of 3mm. (4) After the material is melted, it is injected into the injection mold and the exit mold obtained in step (3). After cooling, the injection gate is removed, and then the surface is physically polished until the surface roughness Ra is 0.008μm to obtain a symmetrical double-sided compound eye lens array. The melting temperature is 220℃, the injection pressure is 80MP, the injection time is 10s, and the cooling time is 20s.

[0054] A comparison between Example 1 and Comparative Example 1 shows that the uniformity of light distribution of the asymmetric double-sided compound eye lens array prepared in Example 1 is 95%, and the uniformity of light distribution of the symmetrical double-sided compound eye lens array prepared in Comparative Example 1 is also 95%. This indicates that the asymmetric double-sided compound eye lens array prepared in this invention has the same performance as the traditional symmetrical double-sided compound eye lens array.

[0055] In Embodiment 1 of the present invention, the injection time and cooling time during injection molding are both half that of Comparative Example 1, resulting in a 50% increase in production efficiency and a significant reduction in production costs.

[0056] Example 2 An asymmetric double-sided compound eye lens array comprises a substrate and an incident lens array and an exit lens array respectively disposed on both sides of the substrate. The asymmetric double-sided compound eye lens array is made of K9 glass with a transmittance of ≥90%. The thickness of the substrate is 2 mm; The exit lens units in the incident lens array are arranged in a regular hexagonal pattern; the number of incident lens units is 144. Both the incident lens unit and the exit lens unit have spherical structures. The incident lens unit has a light-transmitting aperture of 6mm and a focal length of 12mm; the exit lens unit has a light-transmitting aperture of 30% (1.8mm) of the incident lens unit; the number and arrangement of the exit lens units correspond one-to-one with the arrangement of the incident lens units; the focal length of the exit lens unit is the same as that of the incident lens unit. The edge of the exit lens unit is provided with a 0.1mm transition chamfer and a 0.2mm draft angle; The surface roughness Ra of the asymmetric double-sided compound eye lens array is 0.005 μm.

[0057] The method for preparing the asymmetric double-sided compound eye lens array comprises the following steps: (1) Based on the requirement that the uniformity of light distribution of the asymmetric double-sided compound eye lens array is 97%, the aperture of the incident lens unit in the incident lens array is determined to be 6mm, the focal length is 12mm, the number of lens units is 144, and the arrangement is a regular hexagonal arrangement. The thickness of the substrate is determined to be 2mm by injection molding, and the parameters of the incident lens unit are obtained. (2) Under the premise of ensuring that the total light transmission meets the requirements of the optical system, the exit lens unit in the exit lens array is designed asymmetrically. The light transmission aperture of the exit lens unit is 30% (1.8mm) of the light transmission aperture of the incident lens unit, and the parameters of the exit lens unit are obtained (other parameters are the same as those of the incident lens array). (3) Based on the parameters of the incident lens unit obtained in step (1) and the parameters of the exit lens unit obtained in step (2), the incident mold is precision milled and polished after electrical discharge machining to obtain the exit mold; the cavity size of the exit mold matches the light transmission aperture of the exit lens unit; both the incident mold and the exit mold are provided with a side gate and runner with a diameter of 3mm; both the incident mold and the exit mold have built-in heating modules; the maximum temperature that the heating module can withstand is 650℃, and it is suitable for temperatures of 200~600℃; (4) After heating the K9 glass to 580°C to soften it, it is placed into the incident surface mold and the exit surface mold obtained in step (3) for molding. The molding pressure is 8MPa and the time is 8s. After cooling, the flash is removed and then the surface is physically polished until the surface roughness Ra is 0.005μm to obtain an asymmetric double-sided compound eye lens array.

[0058] Comparative Example 2 A symmetrical double-sided compound eye lens array consists of a substrate and an incident lens array and an exit lens array respectively disposed on both sides of the substrate. The symmetrical double-sided compound eye lens array is made of K9 glass with a transmittance of ≥90%; The thickness of the substrate is 2 mm; The exit lens units in the incident lens array are arranged in a regular hexagonal pattern; the number of incident lens units is 144. Both the incident lens unit and the exit lens unit have spherical structures. Both the incident lens unit and the exit lens unit have a light transmission aperture of 6mm and a focal length of 12mm; the number and arrangement of the exit lens units correspond one-to-one with the arrangement of the incident lens units; the focal length of the exit lens units is the same as that of the incident lens units. The edge of the exit lens unit is provided with a 0.1mm transition chamfer and a 0.2mm draft angle; The surface roughness Ra of the symmetrical double-sided compound eye lens array is 0.005 μm.

[0059] The method for preparing the symmetrical double-sided compound eye lens array comprises the following steps: (1) Based on the requirement that the uniformity of light in the symmetrical double-sided compound eye lens array is 97%, the aperture of the incident lens unit in the incident lens array is determined to be 6mm, the focal length is 12mm, the number of lens units is 144, and the arrangement is a regular hexagonal arrangement. The thickness of the substrate is determined to be 2mm by injection molding, and the parameters of the incident lens unit are obtained. (2) Under the premise of ensuring that the total light transmission meets the requirements of the optical system, the exit lens unit in the exit lens array is symmetrically designed, and the parameters of the exit lens unit are the same as those of the incident lens array. (3) Based on the parameters of the incident lens unit obtained in step (1) and the parameters of the exit lens unit obtained in step (2), the incident mold is precision milled and polished after electrical discharge machining to obtain the exit mold; the cavity size of the exit mold matches the light transmission aperture of the exit lens unit; both the incident mold and the exit mold are provided with a side gate and runner with a diameter of 3mm; both the incident mold and the exit mold have built-in heating modules; the maximum temperature that the heating module can withstand is 650℃, and it is suitable for temperatures of 200~600℃; (4) After heating K9 glass to 580°C to soften it, it is placed into the incident surface mold and the exit surface mold obtained in step (3) for molding. The molding pressure is 8MPa and the time is 15s. After cooling, the flash is removed and then the surface is physically polished until the surface roughness Ra is 0.005μm to obtain an asymmetric double-sided compound eye lens array.

[0060] A comparison between Example 2 and Comparative Example 2 shows that the uniformity of light distribution of the asymmetric double-sided compound eye lens array prepared in Example 2 of the present invention is 97%, and the uniformity of light distribution of the symmetrical double-sided compound eye lens array prepared in Comparative Example 2 is also 97%. This indicates that the asymmetric double-sided compound eye lens array prepared in the present invention has the same performance as the traditional symmetrical double-sided compound eye lens array.

[0061] In Example 2 of this invention, the holding time during compression molding is reduced by 47% compared to Comparative Example 2, which meets the high precision requirements of laser processing, increases production efficiency by 40%, and significantly reduces production costs (by about 45%). Furthermore, the yield of Example 2 is 88%, which is 18% higher than that of Comparative Example 2 (70%).

[0062] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An asymmetric double-sided compound eye lens array, characterized in that, It includes a substrate and an incident lens array and an exit lens array respectively disposed on both sides of the substrate; the aperture of the exit lens unit in the exit lens array is 30-70% of the aperture of the incident lens unit in the incident lens array; The incident lens array has incident lens units arranged in a regular polygonal or circular pattern; the number of incident lens units is 50 to 500; the aperture of the incident lens unit is 3 to 10 mm; and the focal length of the incident lens unit is 5 to 20 mm.

2. The asymmetric double-sided compound eye lens array according to claim 1, characterized in that, The asymmetric double-sided compound eye lens array is made of polymer material or hard and brittle material; the polymer material is optical grade acrylic or optical grade polycarbonate; the transmittance of the polymer material is ≥92%; the hard and brittle material is optical glass or optical crystal; the transmittance of the hard and brittle material is ≥90%.

3. The asymmetric double-sided compound eye lens array according to claim 1, characterized in that, The edge of the exit lens unit is provided with a transition chamfer of 0.1~0.5mm.

4. The method for preparing the asymmetric double-sided compound eye lens array according to any one of claims 1 to 3, characterized in that, Includes the following steps: (1) Based on the light uniformity effect of the required asymmetric double-sided compound eye lens array, determine the aperture, focal length, number of lens units and arrangement of the incident lens unit in the incident lens array. Based on the thermoforming method, determine the substrate thickness and obtain the parameters of the incident lens unit. (2) Under the premise of ensuring that the total light transmission meets the requirements of the optical system, the exit lens unit in the exit lens array is designed asymmetrically to obtain the parameters of the exit lens unit; the light transmission aperture of the exit lens unit is 30~70% of the light transmission aperture of the incident lens unit in step (1); (3) The mold is processed according to the parameters of the incident lens unit obtained in step (1) and the parameters of the exit lens unit obtained in step (2) to obtain the incident mold and the exit mold. (4) The material is thermoformed in the incident surface mold and the exit surface mold obtained in step (3) to obtain an asymmetric double-sided compound eye lens array.

5. The preparation method according to claim 4, characterized in that, In step (4), when the material is a polymer material, the thermoforming method is injection molding; the injection molding process is as follows: after melting the material, it is injected into the incident surface mold and the exit surface mold, and after cooling, an asymmetric double-sided compound eye lens array is obtained.

6. The preparation method according to claim 5, characterized in that, The melting temperature is 200~280℃; the injection pressure is 60~100MPa; the injection time is 4~7s; and the cooling time is 8~14s.

7. The preparation method according to claim 4, characterized in that, In step (4), when the material is hard and brittle, the thermoforming method is compression molding; the compression molding process is: after softening the material, it is placed into the injection mold and the exit mold for compression molding.

8. The preparation method according to claim 7, characterized in that, The softening temperature is 500~600℃; the molding pressure is 5~20MPa; and the molding time is 5~15s.

9. The application of the asymmetric double-sided compound eye lens array according to any one of claims 1 to 3 or the asymmetric double-sided compound eye lens array prepared by the preparation method according to any one of claims 4 to 8 in projection display, lighting equipment or laser processing.