Optical lens forming device and method for active surface shape constraint of deformable mold

Abstract

The invention belongs to the field of customized lens forming, and provides an optical lens forming device and method for active surface shape constraint of a deformable mold. A lens forming cavity is defined by the flexible mold body and the circumferential baffle. The deformation of the flexible mold body is controlled by a plurality of ejector rods, the plurality of ejector rods are driven by the same driving assembly, and the driving assembly can move to the position of each ejector rod and drive the ejector rod to do millimeter-level macroscopic linear motion; and each ejector rod is provided with a piezoelectric actuator for driving the ejector rod to do micro-scale or nano-scale microcosmic motion. According to the deformable die, high-precision large-stroke movement of the flexible die body is used for replacing compensation of the offset of a die contour in traditional machining, and rapid response of the die to lenses of different specifications is achieved; the characteristic that the shape of a deformable mold is accurate and controllable in real time is utilized, the curing characteristic of light-cured resin is combined, and the shape of the mold is synchronously adjusted by utilizing quick response of a piezoelectric actuator in the curing process.

Description

Technical Field

[0001] The invention belongs to the field of customized lens forming, and relates to an optical lens forming method and device with active surface shape constraint of a deformable mold. Background Art

[0002] Optical lens forming methods include injection molding, compression molding, cold working molding, polishing molding, etc. Among them, the injection molding method is to inject molten plastic into a mold, and then cool and solidify it in the mold to form the desired optical lens shape. This method is low-cost and suitable for applications such as glasses and mobile phone lenses. However, this method requires different lenses to be equipped with different molds. Under the current mold manufacturing model, only lenses with fixed shapes and specifications can be produced, and it is not flexible to meet the manufacturing needs of lenses with different surface shapes. Therefore, it is not suitable for the production of personalized customized lenses. In addition, in the prior art, since the optical mold surface shape is fixed, the cross-sectional view of the mold cut in half along the symmetry axis is as follows: Figure 1 As shown, its initial state is Figure 1 As shown in (a), the liquid photocurable resin fills the mold cavity. During the curing process of the photocurable resin, due to the free shrinkage of the resin, gaps are generated on the upper surface and side of the lens and the lens is free from the constraints of the mold. Figure 1 As shown in (b), uncontrolled surface error occurs.

[0003] Of course, some deformable mold platforms have also been proposed in the field of optics or other fields, see CN113070406 A, CN115195091A, CN111497273A, US6558590B1, US7516937B2, etc.; however, there are the following problems: In the currently disclosed deformable mold platforms, each ejector pin corresponding to the mold is equipped with an independent driving device. Since the driving device is relatively large, the number of ejector pins that can be set is limited. In order to improve the accuracy of the lens, it is hoped to set as many ejector pins as possible within the same area. However, if the existing ejector pin driving method is directly adopted, the accuracy of the lens cannot be guaranteed. In addition, the current mold design does not achieve joint control with the curing and forming process of the lens resin. This is because, in addition to the influence of the mold on the lens forming accuracy, during the curing and forming process of the lens resin, a cross-linked structure is formed between the molecular chains and the spacing is reduced, resulting in shrinkage, thereby allowing the resin to break away from the constraints of the mold surface and deform freely, resulting in uncontrollable random errors, which also causes a decrease in the accuracy of the lens. Summary of the invention

[0004] In order to solve the technical problems existing in the prior art, the present invention discloses an optical lens forming device and method with active surface shape constraint of a deformable mold; the system and method can realize personalized customization of the lens while ensuring the accuracy and quality of the lens.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows: In a first aspect, an optical lens forming device with active surface shape constraint of a deformable mold comprises a first flexible mold body and a second flexible mold body; a lens forming cavity is formed between the first flexible mold body, the second flexible mold body and a circumferential baffle; The specific deformation of the first flexible mold is controlled by a plurality of first push rods, all of which are driven by the same first driving assembly, which can move to the position of the first push rod to be adjusted and drive it to perform millimeter-level macroscopic linear motion; at the same time, each first push rod is provided with a first micro-motion driving device, which drives the first push rod to perform micro- or nano-level microscopic motion; The specific deformation of the second flexible mold is controlled by a plurality of second push rods, and all the second push rods are driven by the same second driving assembly. The second driving assembly can move to the position of each second push rod and drive it to perform millimeter-level macroscopic linear motion; at the same time, each second push rod is provided with a second micro-motion driving device, and the second micro-motion driving device drives the second push rod to perform micron or nanometer-level microscopic motion.

[0006] The deformable mold of the present invention utilizes the high-precision and large-stroke movement of the flexible mold to replace the traditional processing to compensate for the mold contour offset, thereby realizing the rapid response of the mold to lenses of different specifications; utilizing the real-time and precise controllable surface shape of the deformable mold, combined with the curing characteristics of the photocurable resin, the piezoelectric actuator is used to respond quickly during the curing process, and the mold surface shape is adjusted synchronously, thereby reducing the deformation of the lens caused by material shrinkage and internal stress.

[0007] As a further technical solution, the outer ring of the lens forming cavity is provided with a light source for photocuring resin forming; the first flexible mold body and the second flexible mold body are provided with an interlayer, in which a heating film is installed for thermosetting resin forming.

[0008] As a further technical solution, the first drive assembly includes a two-axis drive mechanism, a motor, and a linear transmission device. The two-axis drive mechanism drives the motor to move in a horizontal plane above the first flexible mold body, and the motor drives the first push rod to move up and down through the linear transmission device.

[0009] As a further technical solution, the first push rod and the second push rod have the same structure and both include a piezoelectric brake. The piezoelectric actuator drives the corresponding first push rod or second push rod to perform micron and nanometer-level microscopic linear motion up and down.

[0010] As a further technical solution, the plurality of first push rods are mounted on a first support plate, and each first push rod is threadedly matched with the first support plate.

[0011] As a further technical solution, the end of the linear transmission device cooperates with the first push rod through a clutch device.

[0012] As a further technical solution, the second drive assembly includes a two-axis drive mechanism, a motor, and a linear transmission device. The two-axis drive mechanism drives the motor to move in the horizontal plane below the second flexible mold body, and the motor drives the second push rod to move up and down through the linear transmission device.

[0013] As a further technical solution, the plurality of second push rods are mounted on a second support plate, and each second push rod is threadedly matched with the second support plate.

[0014] As a further technical solution, the end of the linear transmission device cooperates with the second push rod through a clutch device.

[0015] In the second aspect, based on the above device, the present invention also provides a forming method as follows: Step 1: Obtain the three-dimensional structure of the lens to be formed, and obtain the three-dimensional structure of the surface shape of the first flexible mold body and the second flexible mold body after compensating the lens to be formed in combination with the lens forming material and relevant parameters in the curing process; Step 2: According to the three-dimensional structures of the surface shapes of the first flexible mold body and the second flexible mold body obtained in step 1, the first driving assembly, the second driving assembly, the first ejector rod and the second ejector rod are controlled to perform macro deformation adjustment on the first flexible mold body and the second flexible mold body; Step 3: injecting light-curing resin or heat-curing resin into the lens forming cavity; In step 4, a light source is arranged in the outer circle of the lens forming cavity, or a heating film is arranged in the interlayer of the flexible mold body, so as to control the curing speed of the photocurable resin or the thermosetting resin, and synchronously control the first micro-motion driving device or the second micro-motion driving device to respond quickly, and adjust the mold in the corresponding area to perform micro-deformation, so that the contraction of the photocurable resin or the thermosetting resin is always kept under the specific constraints of the first flexible mold body and the second flexible mold body.

[0016] In the third aspect, the present invention proposes an optical lens forming device with active surface constraint of a deformable mold, comprising a flexible mold body; a lens forming cavity is formed between the flexible mold body, the initial base and the circumferential baffle; the specific deformation of the flexible mold is controlled by a plurality of push rods, and the plurality of push rods are driven by the same driving component, and the driving component can move to the position of each push rod and drive it to perform millimeter-level macroscopic linear motion; each push rod is provided with a piezoelectric actuator to drive the push rod to perform fast-response microscopic motion at the micrometer or nanometer level.

[0017] As a further technical solution, the driving assembly includes a two-axis driving mechanism, a motor, and a linear transmission device. The two-axis driving mechanism drives the motor to move in the horizontal plane below the flexible mold body, and the motor drives the push rod to perform millimeter-level macroscopic linear motion up and down through the linear transmission device.

[0018] As a further technical solution, the first push rod and the second push rod have the same structure and both include a piezoelectric brake. The piezoelectric actuator drives the corresponding first push rod or second push rod to perform micron and nanometer-level microscopic linear motion up and down.

[0019] As a further technical solution, the plurality of push rods are installed on a support plate, and each push rod is threadably matched with the support plate.

[0020] As a further technical solution, the end of the linear transmission device cooperates with the ejector rod through a clutch device.

[0021] In a fourth aspect, based on the above device, the present invention also provides a forming method as follows: Step 1: Obtain the three-dimensional structure of the lens to be formed, and obtain the three-dimensional structure of the specific surface shape of the flexible mold body after compensating the lens to be formed in combination with the lens forming material and relevant parameters in the curing process; Step 2: According to the three-dimensional structure of the surface of the flexible mold body obtained in step 1, the driving assembly and the ejector rod are controlled to perform macroscopic deformation adjustment on the flexible mold body; Step 3: injecting light-curing resin or heat-curing resin into the lens forming cavity; Step 4 sets a light source on the outer circle of the lens forming cavity, or sets a heating film in the interlayer of the flexible mold body, so as to control the curing speed of the photocurable resin or the thermosetting resin, synchronously control the micro-motion drive device for rapid response, and adjust the mold in the corresponding area for micro-deformation, so that the contraction of the photocurable resin or the thermosetting resin is always kept under the constraint of the mold.

[0022] The beneficial effects of the present invention are as follows: 1. The present invention uses a driving assembly to drive a plurality of ejector rods to move independently, thereby realizing controllable deformation of the flexible mold. Since all first ejector rods share a first driving assembly and all second ejector rods share a second driving assembly, the space occupied by each ejector rod is reduced. Therefore, compared with the prior art, as many ejector rods as possible can be arranged within the same area, thereby improving the accuracy of lens forming. At the same time, the first ejector rod and the second ejector rod can be used to form molds of different shapes, effectively avoiding the high cost of manufacturing different molds for different optical lens designs and greatly shortening the product development cycle.

[0023] 2. During the mold forming stage, the present invention utilizes a driving component to realize millimeter-level macroscopic linear motion of the ejector rod, thereby realizing macroscopic forming of the mold; during the optical curing process of the optical lens, the real-time and precise controllable characteristics of the deformable mold surface are utilized, combined with the curing characteristics of the photocurable resin or the thermosetting resin, and a micro-motion driving device is utilized during the curing process to quickly respond and synchronously adjust the mold surface shape, thereby reducing lens deformation caused by material shrinkage and internal stress, and realizing high-precision manufacturing of customized lenses. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of forming a non-deformable mold lens in the prior art; Figure 2 It is a schematic diagram of the overall structure of the optical lens forming device disclosed in Example 1 of the present invention; Figure 3 Schematic diagram of a deformable mold proposed in Example 1 of the present invention; Figure 4 This is a schematic diagram of a lens mold with a prefabricated upper surface disclosed in Example 2 of the present invention; Figure 5 A schematic diagram of a driving component in Embodiment 1 or Embodiment 2 of the present invention; Figure 6 It is a schematic diagram of the process of the forming method disclosed in Example 3 of the present invention; Figure 7 Schematic diagram of a deformable mold using a thermal curing solution proposed in Example 4 of the present invention; Figure 8 It is a schematic diagram of a lens mold with a prefabricated upper surface using a thermal curing method disclosed in Example 4 of the present invention; Fig. 9 The flexible mold strain and deformation simulation diagram of the present invention is shown in FIG. Figure 1 ; Fig.10 The flexible mold strain and deformation simulation diagram of the present invention is shown in FIG. Figure 2 ; Fig.11 Schematic diagram of the simulation of optical lens forming accuracy under non-deformable mold conditions Figure 1 ; Fig.12 Schematic diagram of the simulation of optical lens forming accuracy under non-deformable mold conditions Figure 2 ; Fig.13 It is a schematic diagram of the error distribution simulation along the radial direction of the upper and lower surfaces of the optical lens under the condition of non-deformable mold; Fig.14 Schematic diagram of deformation simulation of optical lens after curing under deformable mold conditions Figure 1 ; Fig.15Schematic diagram of deformation simulation of optical lens after curing under deformable mold conditions Figure 2 ; Fig.16 It is a schematic diagram of the error distribution simulation along the radial direction of the upper and lower surfaces of the lens under the deformable mold working condition; In the figure: 1. photocurable resin; 2. circumferential baffle; 3. light source; 4. second flexible mold body; 5. housing; 6. second push rod; 7. second drive assembly; 8. first flexible mold body, 9. first push rod, 10. first drive assembly; 11. first support plate, 12. second support plate; 13. piezoelectric actuator; 14. lens with prefabricated upper surface; 15. fixture; 16. heating film; 7-1. two-axis drive mechanism; 7-2. motor; 7-3. ball spline shaft; 7-4. clutch; DETAILED DESCRIPTION It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0025] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless otherwise explicitly stated in the present invention, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof; In order to shorten the manufacturing cycle of optical molds, reduce mold processing costs, and achieve precise control of the curing process of photocurable resins to meet the diverse production needs of lenses, this embodiment proposes an optical lens forming method and device with active surface shape constraints of a deformable mold. The deformable mold uses the high-precision and large-stroke movement of the flexible mold to replace the traditional processing to compensate for the mold contour offset, so as to achieve the rapid response of the mold to lenses of different specifications; the deformable mold surface shape is used in real time and precisely controlled, combined with the curing characteristics of photocurable resins or thermosetting resins, and the mold surface shape is synchronously adjusted during its curing process, thereby reducing the deformation of the lens caused by material shrinkage and internal stress. Finally, the high-efficiency and high-precision manufacturing of customized lenses is achieved.

[0026] Example 1 The optical lens forming system with active surface shape constraint of the deformable mold proposed in this embodiment has a structure as follows Figure 1As shown, due to the limitation of mold space and the requirement of dense arrangement of ejector pins to more accurately control the surface shape of the flexible mold body, it is impossible to set an independent power source for all ejector pins. Therefore, the optical lens forming system with active surface shape constraint of the deformable mold proposed in this embodiment adopts a two-axis driving mechanism 7-1 to drive the motor 7-2 to move and adjust the position of the ejector pins in turn. A micro-motion driving device is provided on each ejector pin. In this embodiment, the micro-motion driving device adopts a piezoelectric actuator 13. The piezoelectric actuator 13 can control the synchronous deformation of the mold during the curing process of the photocurable resin 1, so as to realize the microscopic movement of the ejector pin at the micrometer or nanometer level; Specifically, it is mainly composed of a flexible mold body, a first push rod 9, a second push rod 6, a first drive component 10, a second drive component 7, a piezoelectric actuator 13, a shell 5, a light source 3, a circumferential baffle 2, etc.; wherein the flexible mold body is composed of a second flexible mold body 4 and a first flexible mold body 8, the two have the same structure, correspond to the front surface and the rear surface of the optical element respectively, and can be deformed into spherical, aspherical, free-form surface and other surface shapes according to the optical design scheme; the curved surface shape of the second flexible mold body 4 is controlled by a plurality of first push rods 9 and the first drive component 10, and the curved surface shape of the first flexible mold body 8 is controlled by a plurality of second push rods 6 and the second drive component 7; specifically, the first flexible mold body 8, the circumferential baffle 2, and the second flexible mold body 4 are installed in sequence from top to bottom in the middle part of the shell 5, the first flexible mold body 8, the circumferential baffle 2, and the second flexible mold body 4 surround a cavity, and the cavity is used to mold optical lenses, and a plurality of first push rods 9 are arranged above the first flexible mold body 8, and the first push rods 9 are arranged above the first flexible mold body 8. The rod 9 is driven by the first driving assembly 10 to make a linear motion to control the deformation of the first flexible mold body 8. A plurality of second push rods 6 are arranged below the second flexible mold body 4. The second push rods 6 are driven by the second driving assembly 7 to make a linear motion to control the deformation of the second flexible mold body 4. The first driving assembly 10 is movable and can be moved above any first push rod 9 to drive the first push rod 9 to move up and down. The second driving assembly 7 is movable and can be moved below any second push rod 6 to drive the second push rod 6 to move up and down. The first push rod 9 and the second push rod 6 are both provided with a piezoelectric actuator 13 to control the flexible mold body to make a fast-response micrometer and nanometer deformation. Specifically, the first push rod 9 and the second push rod 6 each include two sections, wherein the piezoelectric actuator 13 is arranged between the two sections of the push rods, or the piezoelectric actuator 13 is directly arranged at the head position of the first push rod 9 and the second push rod 6, and the output end of the piezoelectric actuator 13 is a smooth arc shape.

[0027] Furthermore, the first drive assembly 10 drives a plurality of first mandrels 9 to perform linear motion, and the second drive assembly 7 drives a plurality of second mandrels 6 to perform linear motion. The first drive assembly 10 and the second drive assembly 7 have the same structure, and each comprises: a two-axis drive mechanism 7-1, a motor 7-2, a ball spline shaft 7-3, and a clutch 7-4; wherein the two-axis drive mechanism 7-1 enables the motor 7-2 to move in the X and Y directions in the horizontal plane, and the motor 7-2 drives the clutch 7-4 to perform linear motion through a linear transmission device. In this embodiment, the linear transmission device uses a driving ball spline shaft 7-3 and a motor 7-2 to drive the ball spline shaft 7-3 to perform linear, rotational, and spiral motions, thereby meeting the rotational positioning requirements of the mandrel. A tooth clutch 7-4 is installed or processed at the front end of the ball spline shaft 7-3 to achieve torque output to the mandrel.

[0028] Specifically, the motor 7-2 is carried by the two-axis driving mechanism 7-1 to the push rod that needs to be adjusted, and the ball spline shaft 7-3 moves linearly until the clutch 7-4 contacts the push rod, and then the spiral motion drives the push rod to be ejected or retracted axially. This process monitors the rotation angle of the ball spline shaft 7-3, and its axial displacement can be calculated based on the rotation angle and the spiral angle of the ball spline shaft 7-3, thereby achieving accurate control of the axial movement distance of the push rod.

[0029] Further preferably, the first push rod 9 and the second push rod 6 each include several; a support plate is respectively arranged at the upper and lower parts of the shell 5, the first support plate 11 is used to support several first push rods 9, the second support plate 12 is used to support the second push rod 6, and the first support plate 11 and the first push rod 9, and the second support plate 12 and the second push rod 6 are threadedly matched, the helix angle of the first support plate 11, the second support plate 12, the first push rod 9, and the second push rod 6 is less than or equal to the equivalent friction angle, and has a self-locking characteristic, and the torque is provided by the drive component, so that the first push rod 9 and the lower push plate produce axial displacement to drive the flexible mold body to deform.

[0030] Further preferably, the helix angle of the push rod is the same as the helix angle of the spiral groove on the ball spline shaft 7-3, thereby ensuring movement synchronization.

[0031] Further preferably, the top ends of the first push rod 9 and the second push rod 6 are aspherical surfaces, and the maximum curvature radius thereof is smaller than the maximum curvature radius of the mold body after deformation.

[0032] Further preferably, a certain vacuum degree can be maintained in the cavity formed by the second flexible mold body 4, the first flexible mold body 8 and the shell 5, so that the second flexible mold body 4, the first flexible mold body 8 and the top rod can maintain a good fit; or the top rod and the second flexible mold body 4, the first flexible mold body 8 can also be connected by a flexible hinge. In this case, vacuum is no longer required to maintain the specific fit of the flexible molds.

[0033] Further preferably, when the number of ejector rods to be controlled is too large and affects efficiency, the ejector rods may be partitioned according to the total number of ejector rods, and multiple groups of drive components may be provided to adjust the ejector rods synchronously in the partitions.

[0034] Furthermore, the materials of the second flexible mold body 4 and the first flexible mold body 8 can be selected from conventional mold materials such as nickel-phosphorus alloy, etc. As a further preference, materials with better performance such as amorphous alloys, high elastic alloys or shape memory alloys can also be selected. After each batch of components is produced, when the mold body needs to be deformed again according to the surface shape of the next batch of parts, it can be restored to its original shape through elastic recovery, temperature change, etc., and the deformation can be adjusted again according to the new lens shape.

[0035] Furthermore, the second flexible mold body 4 and the first flexible mold body 8 can be restored by applying negative pressure in the circumferential direction or installing springs in addition to their own elastic deformation or thermal recovery to assist the flexible mold body in restoring its initial shape.

[0036] Furthermore, the selection principles of the materials of the second flexible mold body 4 and the first flexible mold body 8 are as follows: For example, when producing a lens with a diopter of D0, the flexible mold body is deformed from a flat surface to a curved surface with a diopter of D0, and the maximum deformation is Δ max , the strain generated at the maximum strain point on the flexible mold body is ε max , the stress generated can be calculated σ max =E×ε max Should satisfy σ max ≤σ e Where E is the elastic modulus of the flexible module, σ e is the specific elastic limit of the flexible module.

[0037] Affected by the elastic limit of the material, a single flexible mold body cannot meet the production of all diopter lenses, so it can be selected and manufactured according to the diopter classification. For example, the flexible mold body has an initial diopter D1 surface shape. When it is deformed to the maximum stress generated reaching the elastic limit, the diopter of the surface shape is D2. Then the flexible mold body can be used for the production of lenses with diopter of D1~D2.

[0038] The driving assembly drives the ejector rod to move, realizes the controllable deformation of the flexible mold, quickly responds to the design of optical lenses with different surface shapes, and the light-curing resin 1 is injected into the mold and cured to form, so that high-quality optical lenses with stable properties can be obtained in batches. The high cost of manufacturing different molds for different optical lens designs is effectively avoided, and the product development cycle is greatly shortened.

[0039] By utilizing the real-time and precise controllable characteristics of the deformable mold surface and combining it with the curing characteristics of the light-curable resin 1, the mold surface shape is adjusted synchronously during the curing process, thereby reducing the lens deformation caused by material shrinkage and internal stress, etc. This enables high-precision manufacturing of customized lenses.

[0040] The cross-sectional view of the optical lens forming mold with active surface shape constraint of the deformable mold proposed in this embodiment is as follows: Figure 3 As shown; according to the parameters of the light-curing resin 1, the curing parameters and the optical lens design parameters, the material shrinkage in different areas of the optical lens is calculated, so as to determine the mold surface shape that compensates for the material shrinkage margin, that is, the initial state is as shown Figure 3 As shown in (a) in FIG. 1 , with the introduction of external conditions such as UV light or heating, the photocurable resin 1 is gradually cured. During this process, the piezoelectric actuator 13 is controlled to make the mold deform synchronously with the contraction of the photocurable resin 1, thereby maintaining the constraint on the photocurable resin 1, as shown in FIG. Figure 3 As shown in (b) in FIG. 1 , the mold is deformed into the designed surface shape, and the light-curable resin 1 is completely cured to obtain the final optical lens, such as Figure 3 As shown in (c) in the figure, this process gradually compensates the material shrinkage margin to the curing process of the light-curing resin 1 through the active surface constraint of the deformable mold, effectively avoiding the generation of gaps and improving the forming accuracy of the optical lens.

[0041] Example 2 This embodiment provides another optical lens forming device with active surface shape constraint of a deformable mold, such as Figure 5 As shown, it is mainly for the case where only one surface of the lens needs to be processed. In the process of manufacturing customized lenses, a lens with one surface prefabricated is sometimes selected as the initial substrate. At this time, the forming device provided in this embodiment can be used for forming; completing the processing of the other surface can further improve the production efficiency of the optical lens.

[0042] Specifically, this embodiment is described by taking a lens that needs to be shaped on the lower surface as an example; Figure 5 The optical lens forming device with active surface shape constraint of the deformable mold shown comprises a housing 5, a fixture 15, a circumferential baffle 2, a lower mold, a second ejector rod 6 and a second driving assembly 7; The lens 14 with the prefabricated upper surface is fixed on the upper part of the housing 5 by a clamp 15. The upper surface of the lens has been formed and coated, and the lower surface needs to be formed according to the customer's customized requirements. The lens 14 with the prefabricated upper surface is positioned and adsorbed on the top of the lower mold by the clamp 15, and the light-curing resin 1 can be injected into the closed cavity formed between the lens 14 with the prefabricated upper surface and the lower mold body. The second driving component 7 drives the movement of the second push rod 6 to change the shape of the lower mold, thereby realizing the shaping control of the lower surface of the lens; Specifically, an optical lens forming method with active surface shape constraint of a deformable mold can be adopted. While curing, the piezoelectric actuator 13 is controlled to adjust the mold deformation of the corresponding area according to the curing speed of the light-curable resin 1, so that the shrinkage of the light-curable resin 1 is always kept under the constraint of the mold, thereby forming a stable and controllable curing shrinkage deformation, and finally forming the designed surface shape of the optical lens. After the light-curable resin 1 is completely cured and demolded, the lens 14 with the prefabricated upper surface and the newly formed resin part form a complete customized lens.

[0043] For this working condition, the selection of light source 3 and curing parameters can be adjusted according to actual needs. For example, a planar ultraviolet light source 3 can be used for overall irradiation to increase the curing speed of the photocurable resin 1; or a planar ultraviolet light source 3 can be used in combination with an aperture to achieve variable-aperture light curing, reduce the stress and deformation caused by the curing of the photocurable resin 1, and improve the lens forming accuracy.

[0044] Example 3 Based on the forming device provided in Example 1 or Example 2, this embodiment further provides a forming method, which is as follows: Step 1: Obtain the three-dimensional structure of the lens to be formed, and obtain the three-dimensional structure of the surface shape of the first flexible mold body 8 and the second flexible mold body 4 after compensating the lens to be formed by combining the lens forming material, the control parameters of the light source 3, and the relevant parameters in the light curing process; Step 2: According to the three-dimensional structures of the surface shapes of the first flexible mold body 8 and the second flexible mold body 4 obtained in step 1, the first driving assembly 10, the second driving assembly 7, the first ejector rod 9, and the second ejector rod 6 are controlled to deform the first flexible mold body 8 and the second flexible mold body 4; Step 3: injecting light-curing resin 1 into the lens forming cavity; Step 4: a light source 3 is arranged at the outer ring of the lens forming cavity, and at the same time, according to the curing speed of the light-curing resin 1, the piezoelectric actuator 13 is controlled to adjust the mold of the corresponding area to perform micro-deformation, so that the contraction of the light-curing resin 1 is always kept under the constraint of the mold, and the forming is performed. After the forming is completed, the lens is taken out; After the batch production is completed in step 5, the corresponding ejector pin is controlled to return to the initial position; if other shapes of lenses need to be formed, the forming can be carried out after readjustment according to the above steps 1 to 4.

[0045] Furthermore, the photocurable resin 1 is cured by irradiation or heating with an annular ultraviolet light source 3, and is gradually cured from the edge of the lens to the center.

[0046] Furthermore, in the above step 1, based on the geometric parameters such as thickness and curvature of different areas of the lens in the optical design, the curing parameters such as light intensity, and the curing characteristic parameters of the photocurable resin 1, the shrinkage amount of different positions of the lens can be obtained, and then a three-dimensional structure of the mold surface with material shrinkage margin can be obtained.

[0047] Among them, during the molding process, the material shrinkage can be obtained according to the following principle: total shrinkage = shrinkage caused by density change + shrinkage caused by temperature change + shrinkage caused by stress change, that is, ;in is the total shrinkage, is the shrinkage caused by density change, The shrinkage caused by temperature change, Shrinkage due to stress changes; The shrinkage caused by the density change is as follows (can also be expressed in volume):

[0048] in, is the initial volume of the optical resin before curing, It is the volume of the optical resin when it is cured and the residual heat and stress are not completely released; is the initial density of the optical resin before curing, It is the density of the optical resin after curing and the residual heat and stress have not been completely released.

[0049] Temperature has a significant effect on the amount of shrinkage during resin curing, especially during light curing, where temperature not only affects the curing rate and crosslinking density of the resin, but also affects the volume expansion or contraction of the resin. The amount of shrinkage can be estimated by introducing the coefficient of thermal expansion:

[0050] in, is the coefficient of thermal expansion, is the initial volume of the optical resin, is the temperature change during the curing process.

[0051] During the resin curing process, stress may be generated inside the resin due to temperature changes, uneven light, uneven material shrinkage, etc. These stresses will affect the volume and shape of the resin. Shrinkage caused by stress changes This can usually be calculated using the stress-strain relationship.

[0052]

[0053] Where E is the elastic modulus of the optical resin, is Poisson's ratio, is the stress during the curing process.

[0054] In order to compare the lens formed by this method with the lens formed by traditional optical molds, the two molds are compared below: The traditional optical mold has a fixed surface shape. The cross-sectional view of the mold cut in half along the symmetry axis is as follows: Figure 1 Its initial state is as follows Figure 1 As shown in (a), the light-curable resin 1 fills the mold cavity. During the curing process of the light-curable resin 1, due to the free shrinkage of the resin, gaps are generated on the upper surface and side of the lens and the lens is free from the constraint of the mold. Figure 1 As shown in (b), uncontrolled surface error occurs.

[0055] Furthermore, in the above step 2, the geometric parameters of the mold model are discretized into the axial movement distance corresponding to each ejector pin, and the two-axis driving mechanism 7-1 drives the motor 7-2 to move, and the position of each ejector pin is adjusted gradually in sequence until it is the same as the mold model. A circumferential baffle 2 is installed between the upper and lower mold bodies, and a photocurable resin 1 is injected after the mold is closed, and it is formed by photocuring and other methods to mass-produce optical lenses.

[0056] Furthermore, in the above step 3, after the photocurable resin 1 is injected into the mold cavity, the deformation of the mold in the corresponding area is adjusted according to the curing speed of the photocurable resin 1 while curing, so that the shrinkage of the photocurable resin 1 is always kept under the constraint of the mold, thereby forming a stable and controllable curing shrinkage deformation, and finally becoming the designed surface shape of the optical lens, and obtaining a qualified customized lens.

[0057] Furthermore, when shape memory alloy is used as the flexible mold body, since the deformation stress of the flexible mold body exceeds the elastic limit or even the yield limit of the memory alloy, the material undergoes plastic deformation and cannot spontaneously recover to the surface shape before deformation. Therefore, it is necessary to change the ambient temperature to restore the flexible mold body to its initial shape. The above process can be repeated to produce the next batch of optical lenses with different surface shapes.

[0058] Furthermore, an amorphous alloy is used as the flexible mold body. Since the flexible mold body is manufactured in a graded manner, the deformation stress is less than the elastic limit of the amorphous alloy, and the material can spontaneously recover to its surface shape before deformation. The above process can be repeated to produce the next batch of optical lenses with different surface shapes.

[0059] It should be noted that, according to simulation cases, the present invention can obtain high-quality optical lenses with a surface accuracy of 0.2-0.3 μm.

[0060] Example 4 Based on the forming device provided in Example 1 or Example 2, in addition to using the light source 3 to cure the light-curable resin 1, a thermosetting resin can also be selected for lens manufacturing. Figure 7 and Figure 8 As shown, a sandwich is added between the second flexible mold body 4 and the first flexible mold body 8, and a heating film 16 is installed.

[0061] Furthermore, the heating film 16 can be heated in different areas to match the curing speed of the thermosetting resin with the deformation speed of the flexible mold. The heat generated by the heating film 16 is transferred to the thermosetting resin through the flexible mold body, and the thermosetting resin is cured stably and evenly by controlling the heating power, and the surface shape of the flexible mold body is adjusted synchronously during the curing process.

[0062] like Figure 7 As shown, optical lenses are manufactured according to customer customization. The upper and lower molds are both deformable molds. The thermosetting resin is injected into the closed cavity formed by the two. The optical lens forming method with active surface shape constraint of the deformable mold is adopted. While heating and curing, the mold deformation of the corresponding area is adjusted according to the curing speed of the thermosetting resin, so that the shrinkage of the thermosetting resin is always kept under the constraint of the mold, thereby forming a stable and controllable curing shrinkage deformation, and finally becoming the designed surface shape of the optical lens. After the thermosetting resin is completely cured and demolded, the thermosetting resin becomes a complete customized lens.

[0063] Selecting a lens with one surface prefabricated as the initial substrate, and then using the optical lens forming method and device with active surface shape constraint of the deformable mold to complete the processing of the other surface can further improve the production efficiency of the optical lens. Figure 8 As shown, the upper surface of the lens 14 with a prefabricated upper surface has been formed and coated, and the lower surface needs to be formed according to the customer's customized requirements. Use a fixture 15 to position the lens and adsorb it on top of the deformable mold, inject a thermosetting resin into the closed cavity formed by the two, and use the optical lens forming method with active surface shape constraint of the deformable mold. While heating and curing, adjust the mold deformation of the corresponding area according to the curing speed of the thermosetting resin, so that the shrinkage of the thermosetting resin is always kept under the constraint of the mold, thereby forming a stable and controllable curing shrinkage deformation, and finally becoming the designed surface shape of the optical lens. After the thermosetting resin is completely cured and demolded, the thermosetting resin and the lens 14 with a prefabricated upper surface become a complete customized lens.

[0064] Further, in order to verify the forming effect of the present invention, different simulations are performed as follows: 1. Flexible mold body strain and deformation simulation Taking Inconel718 as the flexible mold body material as an example, at room temperature, the elastic modulus E=2.06×10 5MPa, elastic limit σ e =414 MPa. When the ejector pushes the flat flexible mold body with a force of 500 N to deform it into a curved surface, the maximum deformation Δ max =0.0286 mm, e.g. Fig. 9 As shown; the corresponding maximum strain ε max =7.8203×10 -4 ,like Fig.10 The maximum stress generated by calculation is as follows σ max =E×ε max =2.06×10 5 MPa×7.4609×10 -4 =153.6945 MPa<414 MPa That is, the flexible mold body is still in an elastically deformed state, and after the ejector rod is retracted, the mold body can spontaneously return to its initial planar state; and the ejector rod force can be further increased, thereby causing the flexible mold body to undergo greater deformation for the production of lenses with greater diopter.

[0065] 2. Optical lens forming accuracy simulation The optical lens forming with active surface shape constraints of deformable molds can effectively avoid the random error problem caused by traditional non-deformable molds. Taking UV light curing as an example, the final forming accuracy of the optical lens under the above two forming schemes is simulated and analyzed. When the light-curing resin 1 is cured, it is irradiated by a circular ultraviolet light source 3, and gradually cured from the edge of the lens to the center. The material properties, UV light parameters and other conditions are kept consistent.

[0066] (1) Optical lens forming under non-deformable mold conditions The light-curing resin 1 fills the mold cavity. The mold surface shape remains unchanged during the curing process. After the curing is completed, the optical lens is deformed as shown in the figure. Fig.11 , Fig.12 As shown; the error distribution of the upper and lower surfaces of the lens along the radial direction is derived respectively, as shown Fig.13 As shown, the maximum errors of the upper and lower surfaces are 0.34μm and 0.45μm respectively.

[0067] (2) Optical lens forming with active surface constraints of deformable molds The light-curing resin 1 fills the mold cavity. During the curing process, the mold surface gradually deforms into the designed surface shape as the curing state progresses. After the curing is completed, the optical lens is deformed as shown in FIG. Fig.14 , Fig.15 As shown; the error distribution of the upper and lower surfaces of the lens along the radial direction is derived respectively, as shown Fig.16 As shown in Figure 2, the maximum errors of the upper and lower surfaces are close to 0.

[0068] From the above simulation results, it can be seen that the optical lens forming with active surface shape constraints of deformable molds can greatly improve the lens forming accuracy.

Claims

1. An optical lens forming device with active surface shape constraint of a deformable mold, characterized in that: It comprises a first flexible mold body and a second flexible mold body; a lens forming cavity is formed between the first flexible mold body, the second flexible mold body and the circumferential baffle; The specific deformation of the first flexible mold is controlled by a plurality of first push rods, all of which are driven by the same first driving assembly, and the first driving assembly can move to the position of the first push rod to be adjusted, and drive it to perform millimeter-level macroscopic linear motion; At the same time, each first push rod is provided with a first micro-motion driving device, which drives the first push rod to perform micro-motion at the micrometer or nanometer level; The specific deformation of the second flexible mold is controlled by a plurality of second push rods, and all the second push rods are driven by the same second driving assembly, and the second driving assembly can move to the position of each second push rod and drive it to perform millimeter-level macroscopic linear motion; At the same time, each second push rod is provided with a second micro-motion driving device, and the second micro-motion driving device drives the second push rod to perform micro-motion at the micrometer or nanometer level.

2. The optical lens forming device with active surface constraint of a deformable mold as claimed in claim 1, characterized in that: The outer ring of the lens forming cavity is provided with a light source for photocuring resin forming; Alternatively, an interlayer is provided in the first flexible mold body and the second flexible mold body, and a heating film is installed in the interlayer for thermosetting resin molding.

3. The optical lens forming device with active surface constraint of a deformable mold as claimed in claim 1, characterized in that: The first drive assembly and the second drive assembly have the same structure, and each includes a two-axis drive mechanism, a motor, and a linear transmission device. The two-axis drive mechanism drives the motor to move in a horizontal plane, and the motor drives the corresponding first push rod or the second push rod through the linear transmission device to perform millimeter-level macroscopic linear motion up and down.

4. The optical lens forming device with active surface constraint of a deformable mold as claimed in claim 3, characterized in that: The plurality of first push rods are installed on a first support plate, and each first push rod is threadedly matched with the first support plate; the plurality of second push rods are installed on a second support plate, and each second push rod is threadedly matched with the second support plate.

5. The optical lens forming device with active surface constraint of a deformable mold as claimed in claim 3, characterized in that: The end of the linear transmission device cooperates with the first push rod or the second push rod through a clutch device.

6. The forming method of the optical lens forming device with active surface shape constraint of a deformable mold as described in any one of claims 1 to 5, characterized in that: Step 1: Obtain the three-dimensional structure of the lens to be formed, and obtain the three-dimensional structure of the surface shape of the first flexible mold body and the second flexible mold body after compensating the lens to be formed in combination with the lens forming material and relevant parameters in the curing process; Step 2: According to the three-dimensional structures of the surface shapes of the first flexible mold body and the second flexible mold body obtained in step 1, the first driving assembly, the second driving assembly, the first ejector rod and the second ejector rod are controlled to perform macro deformation adjustment on the first flexible mold body and the second flexible mold body; Step 3: injecting light-curing resin or heat-curing resin into the lens forming cavity; In step 4, a light source is arranged in the outer circle of the lens forming cavity, or a heating film is arranged in the interlayer of the flexible mold body, so as to control the curing speed of the photocurable resin or the thermosetting resin, and synchronously control the first micro-motion driving device or the second micro-motion driving device to respond quickly, and adjust the mold in the corresponding area to perform micro-deformation, so that the contraction of the photocurable resin or the thermosetting resin is always kept under the specific constraints of the first flexible mold body and the second flexible mold body.

7. An optical lens forming device with active surface shape constraint of a deformable mold, characterized in that: It includes a flexible mold body and an initial substrate; a lens forming cavity is formed between the flexible mold body, the initial substrate and the circumferential baffle; the deformation of the flexible mold body is controlled by a plurality of ejector pins, and the plurality of ejector pins are driven by the same driving assembly, and the driving assembly can move to the position of each ejector pin and drive it to perform millimeter-level macroscopic linear motion; each ejector pin is provided with a micro-motion driving device, and the micro-motion driving device drives the ejector pin to perform micron or nanometer-level microscopic motion.

8. The optical lens forming device with active surface shape constraint of a deformable mold as claimed in claim 7, characterized in that: The driving assembly includes a two-axis driving mechanism, a motor, and a linear transmission device. The two-axis driving mechanism drives the motor to move in the horizontal plane below the flexible mold body, and the motor drives the ejector rod to perform millimeter-level macroscopic linear motion up and down through the linear transmission device.

9. The optical lens forming device with active surface constraint of a deformable mold as claimed in claim 7, characterized in that: The plurality of push rods are installed on a support plate, and each push rod is threadedly matched with the support plate; the end of the linear transmission device is matched with the push rod through a clutch device.

10. The forming method of the optical lens forming device with active surface shape constraint of a deformable mold as claimed in any one of claims 7 to 9, characterized in that: Step 1: Obtain the three-dimensional structure of the lens to be formed, and obtain the three-dimensional structure of the specific surface shape of the flexible mold body after compensating the lens to be formed in combination with the lens forming material and relevant parameters in the curing process; Step 2: According to the three-dimensional structure of the surface of the flexible mold body obtained in step 1, the driving assembly and the ejector rod are controlled to perform macroscopic deformation adjustment on the flexible mold body; Step 3: injecting light-curing resin or heat-curing resin into the lens forming cavity; Step 4 sets a light source on the outer circle of the lens forming cavity, or sets a heating film in the interlayer of the flexible mold body, so as to control the curing speed of the photocurable resin or the thermosetting resin, synchronously control the micro-motion drive device for rapid response, and adjust the mold in the corresponding area for micro-deformation, so that the contraction of the photocurable resin or the thermosetting resin is always kept under the constraint of the mold.

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