Aspherical lens forming device and method with active surface shape constraint of deformable mold

Abstract

The present invention belongs to the field of aspherical lens forming, and discloses an aspherical lens forming device and method with active surface shape constraint for a deformable mold, including a flexible mold body; a lens forming cavity is formed between two flexible mold bodies and a support member, or a lens forming cavity is formed between a flexible mold body, an initial substrate and a support member; the deformation driving device of the flexible mold body includes a number of annular jacks, and the number of annular jacks are arranged in sequence from the center to the outer circle of the flexible mold body to cover the entire flexible mold. Each annular jack is driven by at least two driving devices. Each driving device drives the annular jack to perform a macroscopic linear motion at the millimeter level before the optical resin is cured, and drives the annular jack to perform a microscopic motion at the micron or nanometer level during the curing process of the optical resin.

Description

Technical Field

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

[0002] With the continuous increase in the number of people with vision problems in the market, the demand for aspherical lenses has been continuously expanding. At the same time, with the continuous development of science and technology, VR technology has been continuously improved and its application scope has been continuously expanded. Since problems such as spherical aberration, chromatic aberration, and distortion are more common when wearing VR devices, aspherical lenses are required to optimize and avoid such problems.

[0003] Currently, the forming methods of aspherical lenses are basically the same as those of spherical lenses, including injection molding and compression molding, etc.; however, the method most commonly used in the production of aspherical lenses is injection molding. During the injection molding process, the shape of the mold is generally immutable. To form different lenses, different molds need to be replaced; therefore, the production cost is high and the cycle is long; some flexible molds for lens production have emerged in the prior art. For example, a lens forming device and related method are disclosed in patent AU2002319618A1, but this patent only generally states that the mold can be deformed to adapt to different lenses, but does not disclose how to specifically control the deformation of the mold; a manufacturing process of spectacle lenses is also disclosed in patent US20090146331A1. At the same time, some deformable mold platforms are also disclosed in the prior art, but the deformation of the mold is directly driven by several ejector rods, and this driving method has a relatively high cost; because compared with free-form surface lenses, aspherical lenses are relatively simple, are of a symmetric structure and only need to be optimized on one meridian. If the existing driving method is still used, the cost of the device will be relatively high;

[0004] The materials used for producing lenses are optical resin or photocuring glue, which are combined with an ultraviolet light source for photocuring, without heating, rapid curing, and minimizing the number of processes and operation difficulties as much as possible. During the curing process, since the resin forms a crosslinked structure and the distance between molecular chains decreases when changing from a liquid state and a semi-liquid state to a solid state, its volume will shrink; in addition, due to factors such as curing shrinkage and thermal expansion, stress will be generated inside the resin during the curing process, and stress concentration will cause material deformation and affect the quality of the final product; currently, most of the methods for solving problems such as material shrinkage during the curing process focus on changing the material formula or adjusting the light source required for its curing; however, this adjustment is not jointly controlled with the control of the mold. Therefore, when the precision requirements of the lens are relatively high, the precision requirements of the lens cannot be met. Summary of the Invention

[0005] In order to shorten the manufacturing cycle of optical molds, reduce the mold processing cost, and meet the personalized customization production requirements of diversified lenses, the present invention proposes a deformable mold active surface shape constraint aspherical lens forming device and method. Combining the symmetric design characteristics of aspherical lenses and the characteristics of optimization on one meridian, a ring structure is used to drive the cavity surface of the flexible mold, and high-precision displacement is combined to compensate for the contour offset during the mold processing, so as to achieve the effect of rapid one-time forming. At the same time, during the curing process of the optical resin, due to factors such as curing speed and stress, the change in the distance between the material molecular chains causes shrinkage, and even random errors such as tiny depressions appear on the lens surface, affecting the accuracy of the lens finished product. The present invention controls the displacement of the deformable surface of the mold during the curing process, compensates for the shrinkage amount, and controls the final forming effect at the same time, which can effectively reduce the errors generated during the curing process of the lens, realize the personalized customization of aspherical lenses, improve production efficiency, and flexibly adapt to the production design requirements of various aspherical lenses.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] In the first aspect, the present invention provides an aspherical lens forming device with active surface shape constraint of a deformable mold, including a flexible mold body; a lens forming cavity is formed between two flexible mold bodies and a support member, or a lens forming cavity is formed between a flexible mold body, an initial substrate, and a support member; the deformation driving device of the flexible mold body includes a plurality of annular top members, and the plurality of annular top members are sequentially arranged from the center of the flexible mold body to the outer circle, covering the entire flexible mold body. Each annular top member is driven by at least two driving devices, and each driving device drives the annular top member to perform millimeter-level macroscopic linear motion before the optical resin is cured, and drives the annular top member to perform micron or nanometer-level microscopic motion during the curing process of the optical resin.

[0008] As a further technical solution, each driving device includes a first-stage driving device and a second-stage driving device. The first-stage driving device drives the annular top member to perform millimeter-level macroscopic linear motion before the optical resin is cured, and the second-stage driving device drives the annular top member to perform micron or nanometer-level microscopic motion during the curing process of the optical resin.

[0009] As a further technical solution, for the same flexible mold body, the corresponding driving devices are arranged in a staggered manner.

[0010] As a further technical solution, the contact surface between the annular top member and the flexible mold body is aspherical.

[0011] As a further technical solution, the support member is a transparent member, and a ring of light sources is arranged on its outer circle.

[0012] As a further technical solution, a heating film is arranged in the interlayer of the flexible mold, and the heating films are concentrically arranged in a circular shape in sequence from the center to the outer circle of the flexible mold.

[0013] In a second aspect, the present invention provides a forming method, which is specifically as follows:

[0014] Step 1: Obtain the three-dimensional structure of the lens to be formed, and combine the lens forming material and relevant parameters during the curing process to obtain the three-dimensional structure of the specific surface shape of the flexible mold after compensating the lens to be formed.

[0015] Step 2: According to the three-dimensional structure of the surface shape of the flexible mold obtained in Step 1, control the driving device to perform macroscopic deformation adjustment at the millimeter level and / or microscopic deformation adjustment at the micron or nanometer level on the flexible mold.

[0016] Step 3: Inject liquid photocuring resin or thermosetting resin into the lens forming cavity.

[0017] Step 4: Set a light source outside the lens forming cavity or set a heating film in the interlayer of the flexible mold, and then control the curing speed of the photocuring resin or thermosetting resin. Synchronously control the driving device to make a quick response, and adjust the micro-deformation of the corresponding area of the mold, so that the shrinkage of the photocuring resin or thermosetting resin is always kept under the constraint of the mold.

[0018] As a further technical solution, in Step 2, the control process for the macroscopic deformation of the flexible mold is as follows: drive gradually from the area with small deformation of the mold to the area with large deformation.

[0019] As a further technical solution, in Step 4, the specific cooperative control method of the light source and the driving device is as follows:

[0020] The light source is set in a circle, and during the curing process of the optical resin, it is cured layer by layer from the outer circle to the inner circle, and the intensity of the light source gradually increases during the curing process. At the same time, the driving device drives layer by layer from the outer circle to the inner circle along with the photocuring process.

[0021] As a further technical solution, the specific control method of the heating film and the driving device is as follows:

[0022] Start thermosetting from the thickest position of the thermosetting resin, and the corresponding driving device drives according to the thermosetting deformation.

[0023] The beneficial effects of the present invention are as follows:

[0024] By combining the symmetric design characteristics of the aspherical lens and the characteristics of being optimized on one meridian, the present invention drives the cavity surface of the flexible mold body by means of an annular top piece, and combines high-precision displacement to meet the contour offset compensation during the mold processing, so as to achieve the effect of one-time rapid forming. Moreover, by utilizing the characteristics of high precision, controllability and deformability of the deformable mold, it works in coordination with the photocuring / thermal curing process, compensates for the resin shrinkage through the deformation of the flexible mold body, and at the same time restricts the shrinkage direction and curing shape to avoid the randomness during the free curing of the resin; the shrinkage change is constrained in the controllable surface deformation process, improving the surface shape accuracy and the yield rate of the product.

[0025] In the present invention, the driving component drives the annular top piece to move, realizing the controllable deformation of the flexible mold body, quickly responding to the aspherical optical lens design of different data. After the liquid photocuring glue or optical resin is injected into the mold, it is formed by photocuring or thermal curing, and high-quality optical lenses with stable properties can be obtained in batches; effectively avoiding the high cost of manufacturing different molds for different optical lens designs and greatly shortening the product R & D cycle. Brief Description of the Drawings

[0026] Figure 1 It is a flowchart of the aspherical lens forming method with active surface shape constraint of the aspherical lens forming device proposed by the present invention;

[0027] Figure 2 It is a schematic diagram of the aspherical lens forming device with active surface shape constraint of the deformable mold proposed in Embodiment 1 of the present invention Figure 1 ;

[0028] Figure 3 It is a schematic diagram of the aspherical lens forming device with active surface shape constraint of the deformable mold proposed in Embodiment 1 of the present invention Figure 2 ;

[0029] Figure 4 It is a schematic diagram of the aspherical lens forming device with active surface shape constraint of the deformable mold proposed in Embodiment 1 of the present invention Figure 3 ;

[0030] Figure 5 It is a schematic diagram of the aspherical lens forming device with active surface shape constraint of the deformable mold proposed in Embodiment 1 of the present invention Figure 4 ;

[0031] Figure 6 It is a schematic diagram of the aspherical lens forming device with active surface shape constraint of the deformable mold proposed in Embodiment 2 of the present invention;

[0032] Figure 7 It is a schematic diagram of the aspherical lens forming device with active surface shape constraint of the deformable mold proposed in Embodiment 3 of the present invention;

[0033] In the figure: 1. Outer shell; 2. First two-stage driving device; 2-1. First-stage driving device, 2-2. Second-stage driving device, 3. First annular top piece; 4. First flexible mold body; 5. Injection port; 6. Optical resin; 7. Ultraviolet light source; 8. Support piece; 9. Second flexible mold body; 10. Second two-stage driving device; 11. Second annular top piece; 13. Initial substrate; 14. Fixture; 15. Heating film. Detailed implementation mode

[0034] It should be noted that the following detailed description is illustrative and aims to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0035] It should be noted that the terms used herein are only for describing specific implementation modes and are not intended to limit the exemplary implementation modes according to the present invention. As used herein, unless the present invention clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof;

[0036] In order to shorten the manufacturing cycle of the optical mold, reduce the mold processing cost, and meet the personalized customization production requirements of diversified lenses, this embodiment proposes an aspherical lens forming device with active surface shape constraint of a deformable mold. Combining the symmetric design characteristics of the aspherical lens and the characteristics of being optimized on one meridian, the cavity surface of the flexible mold body is driven by an annular structure, and high-precision displacement is combined to meet the profile offset compensation during the mold processing, so as to achieve the effect of one-time rapid forming. At the same time, during the curing process of the optical resin 6, due to the influence of factors such as curing speed and stress, the change in the molecular chain spacing of the material causes shrinkage, and even random errors such as tiny depressions appear on the lens surface, affecting the accuracy of the lens finished product. And the present invention can effectively reduce the errors generated during the curing process of the lens by controlling the displacement of the deformable surface of the mold during the curing process, compensating for the shrinkage amount, and controlling the final forming effect, realizing the personalized customization of the aspherical lens, improving the production efficiency and flexibly adapting to the production design requirements of various aspherical lenses.

[0037] Embodiment 1

[0038] This embodiment provides an aspherical lens forming device with active surface shape constraint of a deformable mold, and the structure is as Figure 2 、 Figure 3 、 Figure 4As shown in the figure, it mainly consists of a housing 1, a first flexible mold 4, a first annular ejector 3, a first two-stage driving device 2, a second flexible mold 9, a second annular ejector 11, a second two-stage driving device 10, and a support 8;

[0039] The first flexible mold 4 and the second flexible mold 9 are arranged vertically, and together with the support 8, they enclose a lens forming cavity; a resin injection port 5 is provided on the support 8, and after the resin is injected, the resin injection port 5 is closed;

[0040] The deformation driving device of the first flexible mold 4 includes a number of first annular ejectors 3. The first annular ejectors 3 are sequentially arranged from the center of the first flexible mold 4 to the outer circle, covering the entire first flexible mold. Each first annular ejector 3 is driven by at least two first driving devices. The first driving device drives the annular ejector to perform a macroscopic linear motion at the millimeter level before the optical resin 6 cures, and drives the annular ejector to perform a microscopic motion at the micron or nanometer level during the curing process of the optical resin 6;

[0041] The deformation driving device of the second flexible mold 9 includes a number of second annular ejectors 11. The second annular ejectors 11 are sequentially arranged from the center of the second flexible mold 9 to the outer circle, covering the entire second flexible mold. Each second annular ejector 11 is driven by at least two second driving devices. The second driving device drives the annular ejector to perform a macroscopic linear motion at the millimeter level before the optical resin 6 cures, and drives the annular ejector to perform a microscopic motion at the micron or nanometer level during the curing process of the optical resin 6.

[0042] Furthermore, the materials of the first flexible mold 4 and the second flexible mold 9 can be high-elasticity alloys or shape memory alloys. When the molds need to be deformed after each batch of components is produced, they can be restored to their initial shapes by elastic recovery and temperature change respectively, and then adjusted for deformation according to the new lens shape again. In addition to relying on its own elastic deformation or thermal recovery, the flexible mold can apply negative pressure in the circumferential direction or install springs to assist the flexible mold to restore its initial shape.

[0043] Furthermore, the materials of the first flexible mold 4 and the second flexible mold 9 can also be shape memory polymers (such as styrene and vinyl compounds, and crosslinking agents, initiators, and modified polymers are added on this basis). Compared with shape memory alloys, they have greater fatigue strength and better deformation recovery. After the flexible mold is restored to its initial shape, the above process can be repeated to produce optical lenses with different surface shapes.

[0044] Furthermore, each annular top piece is used to apply a deformation force to the flexible mold body. Since the aspherical lens is symmetrically designed, an annular top piece is used instead of a top rod. At the same time, the aspherical lens is optimized on a meridian relative to the spherical lens, so the annular structure is nested and distributed in a progressive manner, and the different top-up heights between each layer are used to achieve optimization on a meridian. The upper end of the annular top piece adopts an aspherical surface to avoid local protrusions and poor bonding as much as possible.

[0045] Furthermore, the drive device uses a staggered arrangement of micro electric cylinders or linear actuators as a power source, and each micro electric cylinder or linear actuator corresponding to the annular top piece is connected in series. The end of the drive device is directly connected to the annular top piece, and the electric cylinder or actuator connected to the annular top piece synchronously and directly drives the axial displacement of the top piece. Of course, the annular top piece can also be connected by using a lead screw, using a voice coil motor as a driving power source, and using the angle characteristics of the lead screw nut to achieve self-locking. The drive components corresponding to each annular top piece of different diameters are arranged in a staggered manner.

[0046] Furthermore, each of the driving devices can also be designed as a two-stage drive, that is, a macro-micro drive structure design, and its accuracy is ensured to meet the application requirements through two-stage drive. Specifically, by setting piezoelectric ceramics at the end of the top rod of the micro electric cylinder or linear actuator, the micro electric cylinder or linear actuator is used as the first-stage driving device, that is, a macro driving device; piezoelectric ceramics are used as the second-stage driving device, that is, a micro driving device, to ensure the surface accuracy and fine-tuning during the resin curing process, and to ensure the surface quality of the final product. Specifically in this embodiment, the first driving device in this embodiment is a first two-stage driving device 2, the first two-stage driving device 2 includes a first-stage driving device 2-1 and a second-stage driving device 2-2, the first-stage driving device 2-1 is a micro electric cylinder or linear actuator, and the second-stage driving device 2-2 is a piezoelectric ceramic; correspondingly, the second driving device is a second two-stage driving device 10, and the second two-stage driving device 10 also includes a first-stage driving device and a second-stage driving device, the first-stage driving device is a micro electric cylinder or linear actuator, and the second-stage driving device is a piezoelectric ceramic.

[0047] Furthermore, the micro-electric cylinder or linear actuator, as the first-stage driving device, generates a macroscopic driving of millimeter-level displacement when driving the deformation of the flexible mold body, and the mechanical error of the driving device can be ignored at this time. The piezoelectric ceramic, as the second-stage driving device, fine-tunes the surface shape after the first driving device finishes working, and compensates for its shrinkage and controls the surface shape during the curing process of the optical resin 6, and can generate microscopic movement of micrometer-level or even nanometer-level displacement.

[0048] Further, to avoid errors, the ejector rod of the micro electric cylinder or linear driver in this embodiment is connected to the housing 1 through a linear bearing to avoid obvious radial deviation during the movement. Specifically, Figure 4 This is the top view of the present invention after removing the upper housing 1. Each ring can be driven by 2-3 drivers, and the position during the movement is ensured not to deviate by the ultra-precision clearance fit between the rings, ensuring its final position accuracy. In addition, the surface accuracy after deformation can be ensured by adding gaskets on the contact surface between the deformable mold and the annular ejector or using an appropriate material thickness to avoid obvious annular protrusions.

[0049] Further, the above-mentioned support member is made of a transparent material, and an ultraviolet light source 7 is provided in a circle on the outer ring of the support member;

[0050] Further, due to the different curing speeds and uneven internal stress distribution of the optical resin 6 during the curing process, its volume will shrink after curing, and the deformable mold can use its high-precision and deformable characteristics to make certain compensation for it. For example, the shrinkage amount of the optical resin 6 can be calculated in advance, and a margin can be left in the initial deformation stage. At the beginning of curing, according to the different curing stages, pressure is gradually applied to the deformable surface of the mold from the outside to the inside to make the flexible mold deform, so as to adjust the shrinkage rate and shape of the resin, and finally cure to reach the best profile designed in advance. At the same time, applying pressure to the cured area helps to balance the stress generated during the curing process in the area being cured.

[0051] The idea of calculating its shrinkage amount is as follows: the total shrinkage amount = shrinkage caused by density change + shrinkage caused by temperature change + shrinkage caused by stress change, that is .

[0052] Among them, the shrinkage caused by density change is as follows (it can also be expressed in volume):

[0053]

[0054] Temperature has a significant impact on the shrinkage amount of the resin during the curing process. Especially during the photo-curing process, temperature not only affects the curing rate and crosslinking density of the resin, but also affects the volume expansion or contraction of the resin. Specifically, the volume change of the resin caused by temperature change can be estimated by introducing the coefficient of thermal expansion to calculate the shrinkage amount:

[0055]

[0056] During the resin curing process, due to reasons such as temperature change, uneven light, and uneven shrinkage of materials, stress may be generated inside the resin. These stresses will affect the volume and shape of the resin. The volume change caused by stress can usually be calculated through the stress-strain relationship.

[0057]

[0058] where E is the elastic modulus of the resin material used, is the Poisson's ratio, is the stress during the curing process, and the stress distribution during the curing process can be simulated.

[0059] Based on the above description of the deformable mold and the shrinkage during the curing process, the forming process of the aspherical lens can be optimized. Combining the data of the required lens production to obtain the required surface shape, where the aspherical surface shape is usually described by the following formula:

[0060]

[0061] where z is the sag of the surface, c is the curvature at the vertex of the aspherical surface, and k is the conic coefficient. When k > 0, it is a prolate ellipse; when k = 0, it is a spherical surface; when k = -1, it is a paraboloid; when k < -1, it is a hyperboloid; when -1 < k < 0, it is an oblate ellipse. In addition, this formula is a two-dimensional description of the base of the mirror shape. When converted to a three-dimensional coordinate system, it is:

[0062]

[0063] After obtaining the required surface shape, according to the geometric parameters such as the thickness and curvature of different regions of the lens in optical design, the curing parameters such as the light intensity, and the curing characteristic parameters of the optical resin 6, the shrinkage amount at different positions of the lens can be obtained, and then the mold surface shape with material shrinkage allowance can be obtained.

[0064] Furthermore, in this embodiment, the resin curing can be carried out by a UV light source. During the curing process, the mold annular top piece is driven to deform the deformable surface to compensate for the shrinkage error and constrain the cured surface shape, so that the curing process of the optical resin 6 is always carried out under the constraint of the mold surface, and finally the required shape is formed to obtain a surface shape accuracy of less than 0.5 microns. (The process is as Figure 1 shown).

[0065] In this embodiment, the driving component drives the annular top piece to move, realizing the controllable deformation of the flexible mold body, quickly responding to the design of aspherical optical lenses with different data. After the liquid light-curing glue or optical resin 6 is injected into the mold, it is formed by light curing or thermal curing, and high-quality optical lenses with stable properties can be obtained in batches. It effectively avoids the high cost of manufacturing different molds for different optical lens designs and greatly shortens the product R & D cycle. At the same time, by utilizing the deformable characteristics of the mold cavity surface in this mold, during the curing process, the driving surface generates deformation, and in the process of free curing, the surface shape is controlled to have a synergistic effect, constraining the shrinkage change in the controllable surface deformation process, and improving the surface shape accuracy and the yield rate of the product.

[0066] The specific forming process of the above device is as follows:

[0067] Step 1 After the optical lens is designed and finalized, a three-dimensional model of the optical lens can be obtained. According to parameters such as the shrinkage rate of the photocuring glue or optical resin 6 during the curing process, the models of the first flexible mold body 4 and the second flexible mold body 9 are obtained.

[0068] Step 2 Discretize the geometric parameters of the models of the first flexible mold body 4 and the second flexible mold body 9 into the axial movement distances corresponding to each annular top piece, and gradually adjust the positions of each annular top piece one by one until they are the same as the mold model to obtain the lens forming cavity.

[0069] Step 3 Inject liquid photocuring resin into the lens forming cavity.

[0070] Step 4 Set an ultraviolet light source 7 outside the lens forming cavity, and then control the curing speed of the photocuring resin. Synchronously control the driving device to respond quickly, and adjust the corresponding area of the mold for micro-deformation, so that the shrinkage of the photocuring resin or thermosetting resin is always kept under the constraint of the mold.

[0071] In the said Step 2, the control process for the macroscopic deformation of the flexible mold body is: driving gradually from the area with small deformation of the mold body to the area with large deformation; in this embodiment, a concave-convex lens is formed. Figure 1 During the macroscopic forming process, the upper mold is driven step by step from the outer ring to the inner ring; the lower mold is driven step by step from the outer ring to the inner ring.

[0072] As a further technical solution, in the said Step 4, the specific cooperative control method of the ultraviolet light source 7 and the driving device is as follows: The ultraviolet light source 7 is set in a circle, and during the curing process of the optical resin 6, it is cured step by step from the outer ring to the inner ring, and the intensity of the ultraviolet light source 7 gradually increases during the curing process. At the same time, the driving device is driven step by step from the outer ring to the inner ring along with the photocuring process.

[0073] After completing the production of this batch, control the top piece to return to the initial position. During this process, the flexible mold body restores its initial shape through elastic recovery (high-elastic alloy, amorphous alloy) or by changing the temperature (shape memory alloy), and then the above process can be repeated to produce optical lenses with different surface shapes.

[0074] Embodiment 2

[0075] Compared with designing both the front and back surfaces of the lens, for some production requirements with relatively small personalized needs or relatively low requirements for the surface shape, the design difficulty can be reduced and the mass production efficiency can be improved by designing one of the surfaces as a plane or using a designed fixed surface shape mold.

[0076] Such as Figure 6As shown, the lens with the prefabricated upper surface serves as the initial substrate 13. The upper surface has been formed and coated, and the formation of the lower surface needs to be completed according to the customized requirements of customers. The initial substrate 13 is fixed above the deformable mold body using the fixture 14, and the optical resin 6 is injected into the enclosed cavity formed by the two. Using the optical lens forming method with active surface shape constraint of the deformable mold, while curing, according to the curing speed of the optical resin 6, the deformation of the corresponding area of the mold is adjusted, so that the shrinkage of the optical resin 6 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 optical resin 6 is completely cured and demolded, it becomes a complete customized lens.

[0077] For this working condition, the selection of the ultraviolet light source 7 and the curing parameters, etc. can be adjusted according to actual needs. For example, a planar ultraviolet light source 7 can be selected for overall irradiation to increase the curing speed of the optical resin 6; or a planar ultraviolet light source 7 can be used in cooperation with a diaphragm to achieve variable-aperture light curing, reduce the stress and deformation generated during the curing of the optical resin 6, and improve the lens forming accuracy.

[0078] Embodiment III

[0079] In addition to being applicable to light curing forming, the device in Embodiment I or Embodiment II is also suitable for thermal curing forming. The difference from Embodiment I or Embodiment II is that the ultraviolet light source 7 is no longer provided in the device, and instead a heat source is provided. At the same time, the lens forming cavity is filled with thermosetting resin; during the thermal curing process, the mold annular top member is driven to cause deformation of the deformable surface to compensate for the shrinkage error and constrain the cured surface shape, so that the curing process of the optical resin 6 is always carried out under the constraint of the mold surface, and finally the desired shape is formed, and a surface shape accuracy of less than 0.5 micrometers is obtained.

[0080] Specifically, as Figure 7 shown, a heating film 15 is placed inside the material of the flexible mold body in Embodiment I or Embodiment II, which can enable the lens to be finally formed by thermal curing. Since temperature is an important factor affecting the curing rate and curing effect during the thermal curing process, the curing speed of the resin can be controlled by adjusting the heating power of the heating film 15. At that time, according to relevant conditions such as temperature, the shrinkage amount and shrinkage rate of the thermosetting optical resin 6 are obtained, and then its shrinkage is compensated, its shrinkage direction and the final surface shape are controlled, and the final surface shape and ideal accuracy desired in this application can be obtained. For example, a ring-shaped heating film corresponds to the ring-shaped top member, and heating starts from the place where more resin is injected. For example, in Figure 7In the middle, the outer heating film can be first heated to ensure that the outer layer where there is more resin is cured first, and then the inner heating film 15 is heated to ensure the synchronous curing of the internal resin, so as to reduce the internal stress caused by uneven curing. At the same time, when the outer heating film 15 starts to be heated first, the outer ring-shaped top part is first driven to compensate for the shrinkage deformation, and then as the internal part gradually starts to be heated, the inner ring is also driven to compensate for the shrinkage deformation.

Claims

1. Aspherical lens forming device with active surface shape constraint of deformable mold, characterized in that It includes flexible mold bodies; between two flexible mold bodies and a support member, a lens forming cavity is formed, or between a flexible mold body, an initial substrate, and a support member, a lens forming cavity is formed; the deformation driving device of the flexible mold body includes a plurality of annular top members, which are sequentially arranged from the center of the flexible mold body to the outer ring, covering the entire flexible mold body. Each annular top member is driven by at least two driving devices. Each driving device drives the annular top member to perform a macroscopic linear motion at the millimeter level before the optical resin is cured, and during the curing process of the optical resin, drives the annular top member to perform a microscopic motion at the micron or nanometer level.

2. The aspherical lens forming device with active surface shape constraint of a deformable mold according to claim 1, characterized in that Each of the driving devices includes a first-stage driving device and a second-stage driving device. The first-stage driving device drives the annular top member to perform a macroscopic linear motion at the millimeter level before the optical resin is cured, and the second-stage driving device drives the annular top member to perform a microscopic motion at the micron or nanometer level during the curing process of the optical resin.

3. The aspherical lens forming device with active surface shape constraint of a deformable mold according to claim 1, characterized in that, For the same flexible mold body, the corresponding driving devices are arranged in a staggered manner.

4. The aspherical lens forming device with active surface shape constraint of a deformable mold according to claim 1, characterized in that, The contact surface between the annular top member and the flexible mold body is an aspherical surface.

5. The aspherical lens forming device with active surface shape constraint of a deformable mold according to claim 1, characterized in that, The support member is a transparent member, and a ring of light sources is arranged on its outer ring.

6. The aspherical lens forming device with active surface shape constraint of a deformable mold according to claim 1, wherein, A heating film is arranged in the sandwich layer of the flexible mold body, and the heating films are sequentially arranged in concentric circles from the center of the flexible mold body to the outer ring.

7. The forming method of the aspherical lens forming device with active surface shape constraint of a deformable mold according to any one of claims 1-6, characterized in that Specifically as follows: Step 1: Obtain the three-dimensional structure of the lens to be formed. Combine the lens forming material and relevant parameters during the curing process, and after compensating the lens to be formed, obtain the three-dimensional structure of the specific surface shape of the flexible mold body. Step 2: According to the three-dimensional structure of the surface shape of the flexible mold body obtained in Step 1, control the driving device to perform macroscopic and / or microscopic deformation adjustment at the millimeter level on the flexible mold body. Step 3: Inject liquid photocuring resin or thermosetting resin into the lens forming cavity. Step 4: Set a light source on the outer ring of the lens forming cavity, or set a heating film in the sandwich layer of the flexible mold body, thereby controlling the curing speed of the photocuring resin or thermosetting resin. Synchronously control the driving device to perform a quick response, adjust the corresponding area of the mold for micro-deformation, so that the shrinkage of the photocuring resin or thermosetting resin is always kept under the constraint of the mold.

8. The shaping method according to claim 7, wherein In Step 2, the control process for the macroscopic deformation of the flexible mold body is: drive gradually from the area with small deformation of the mold body to the area with large deformation.

9. The shaping method according to claim 7, characterized in that, In Step 4, the specific cooperative control method of the light source and the driving device is as follows: The light source is set in a ring. During the curing process of the optical resin, it is cured layer by layer from the outer ring to the inner ring, and the intensity of the light source gradually increases during the curing process. At the same time, the driving device is driven layer by layer from the outer ring to the inner ring along with the photocuring process.

10. The shaping method according to claim 7, characterized in that, The specific control method of the heating film and the driving device is as follows: Start the thermosetting from the thickest position of the thermosetting resin, and the corresponding driving device is driven according to the thermosetting deformation.

Images