Method and device for compensating surface shape-optical error of mould pressing mould of glass optical element

Abstract

The invention discloses a surface shape-optical error compensation method and device for a glass optical element mold pressing mold. The method comprises the following steps: determining high-temperature viscoelasticity parameters of glass by using a creep test method based on constant-pressure stress micro-deformation low-friction disturbance axial compression; an initial glass optical element contour curve equation is constructed to determine initial mold pressing mold parameters, and then a glass preform simulation model under the force-heat coupling effect is established; simulating the compression molding process by using the simulation prediction model to obtain a simulated glass optical element, and predicting to obtain a predicted surface shape error and a predicted optical error of the simulated glass optical element; and compensating the initial mold pressing mold parameters based on the predicted surface shape error and the predicted optical error so as to manufacture a compensated mold pressing mold based on the compensated mold pressing mold parameters. According to the method, surface shape-optical error compensation can be carried out on parameters of the mold pressing mold, and the compensated mold pressing mold can be subjected to one-time mold pressing forming to obtain a glass optical element with high precision and high optical performance.

Description

Technical Field

[0001] The present invention relates to the technical field of ultra-precision molding, and in particular to a method for compensating the surface shape and optical error of an ultra-precision molding die for a glass optical element and a device for compensating the surface shape and optical error of an ultra-precision molding die for a glass optical element. Background Art

[0002] Traditional glass optical component manufacturing processes mainly include cold processing processes such as ultra-precision grinding, polishing or single-point diamond turning. Although these cold processing processes can achieve high-precision manufacturing of glass optical components, they have problems such as low processing efficiency and poor consistency. Especially with the rapid development of industries such as semiconductor lithography and precision optical devices, large-scale manufacturing of glass optical components is required. How to manufacture nano-precision fused quartz optical components at low cost, high efficiency and in large quantities faces major challenges.

[0003] As a hot forming technology, precision glass compression molding technology heats the glass to its softening temperature and then applies molding pressure to replicate the mold surface morphology onto the glass surface, and obtains glass optical components after cooling and annealing. The process flow of glass optical component compression molding is: mold design → mold manufacturing → mold coating → compression molding. During the compression molding process of glass optical components, since optical glass is in a viscoelastic state, it will expand and contract after annealing and cooling, causing the contour curve of the molded glass component to deviate from the designed contour curve of the glass optical component, thereby causing a large surface error.

[0004] In order to achieve nano-precision compression molding of glass optical components, it is necessary to compensate for the thermal expansion and contraction of the glass in the compression mold. According to the existing compensation method, the mold is compensated and corrected by the surface error of the optical component obtained by the compression test, which requires repeated tests to correct the mold. This method has the problems of large correction times, high cost and long cycle. In addition, in addition to the surface error that will affect the molding performance of the glass optical component, the residual stress of the glass optical component during the annealing and cooling stage will also affect its optical properties (such as refractive index). Therefore, it is also necessary to compensate for the optical error of the mold. However, the existing compression molding technology for glass optical components does not take into account the optical error compensation of the mold, resulting in poor optical performance of the glass optical components obtained by compression molding.

[0005] Therefore, a method for compensating the surface shape and optical error of a glass optical element molding mold is needed to solve the problems existing in the above technical solutions. Summary of the invention

[0006] To this end, the present invention provides a glass optical element molding mold surface shape-optical error compensation method and a glass optical element molding mold surface shape-optical error compensation device to solve or at least alleviate the above problems.

[0007] According to one aspect of the present invention, a method for compensating the surface shape-optical error of a glass optical element molding die is provided, which is executed in a computing device and includes: obtaining the creep displacement of the glass by using a creep testing method based on constant pressure stress micro-deformation low friction disturbance axial compression, and determining the high-temperature viscoelastic parameters of the glass based on the creep displacement; constructing an initial glass optical element profile curve equation, and determining the initial molding die parameters based on the initial glass optical element profile curve equation; establishing a glass preform simulation model under force-heat coupling based on the initial molding die parameters; simulating the molding process by using a simulation prediction model based on the initial molding die parameters, the glass preform simulation model and the high-temperature viscoelastic parameters of the glass to obtain a simulated glass optical element, and predicting the surface shape error and optical error of the simulated glass optical element to obtain the corresponding predicted surface shape error and predicted optical error; compensating the initial molding die parameters based on the predicted surface shape error and predicted optical error to obtain compensated molding die parameters, so as to manufacture a compensated molding die based on the compensated molding die parameters.

[0008] Optionally, in the surface shape-optical error compensation method for a glass optical element molding mold according to the present invention, the compensated molding mold is used to perform a molding test to obtain a test surface shape error and a test optical error of the glass optical element after the test; the method further includes: determining a test surface shape error and a test optical error of the glass optical element after the test obtained by performing a molding test using the compensated molding mold; judging whether the test surface shape error and the test optical error are respectively less than a surface shape error threshold and an optical error threshold, and if not, then: based on the test surface shape error and the test optical error of the glass optical element after the test, correcting the simulation prediction model to obtain the corrected simulation prediction model; using the corrected simulation prediction model, based on Based on the initial molding mold parameters, the glass preform simulation model and the glass high-temperature viscoelastic parameters, the molding process is simulated to obtain a simulated glass optical element, and the surface error and optical error of the simulated glass optical element are predicted to obtain the corresponding predicted surface error and predicted optical error; based on the predicted surface error and predicted optical error, the initial molding mold parameters are compensated to obtain compensated molding mold parameters, so as to manufacture a compensated molding mold based on the compensated molding mold parameters; the above steps are iteratively performed until the test surface error and test optical error of the test glass optical element are respectively less than the surface error threshold and the optical error threshold, and the simulation prediction model corrected this time is used as the final simulation prediction model.

[0009] Optionally, in the glass optical element molding mold surface shape-optical error compensation method according to the present invention, the molding process includes a molding stage and an annealing and cooling stage; based on the initial molding mold parameters, the glass preform simulation model and the glass high-temperature viscoelastic parameters, the molding process is simulated to obtain a simulated glass optical element, including: determining molding process conditions, the molding process conditions including an initial temperature, a target temperature, and a predetermined molding pressure; based on the initial molding mold parameters, the glass preform simulation model and the glass high-temperature viscoelastic parameters, and according to the molding process conditions, the molding stage of the glass preform is simulated to obtain an initial glass optical element as a molding result; using the molding result as the initial condition of the annealing and cooling stage to simulate the annealing and cooling stage to obtain a simulated glass optical element.

[0010] Optionally, in the surface shape-optical error compensation method of the glass optical element molding mold according to the present invention, the predicted optical error includes the glass refractive index; the surface shape error and optical error of the simulated glass optical element are predicted to obtain the corresponding predicted surface shape error and predicted optical error, including: using the interpolation method to fit the node coordinates of the simulated glass optical element and the node coordinates of the initial molding mold corresponding to the initial molding mold parameters to determine the predicted surface shape error of the simulated glass optical element; constructing a volume change-refractive index model of the glass optical element in the annealing and cooling stage, the volume change-refractive index model of the glass optical element is used to simulate the volume and refractive index changes of the glass optical element in the annealing and cooling stage; by solving the volume change-refractive index model of the glass element, the final refractive index of the simulated glass optical element is obtained, and the final refractive index is used as the glass refractive index of the simulated glass optical element.

[0011] Optionally, in the surface shape-optical error compensation method of a glass optical element molding mold according to the present invention, the initial molding mold parameters are compensated based on the predicted surface shape error and the predicted optical error to obtain compensated molding mold parameters, including: performing optical error compensation on the initial glass optical element contour curve equation based on the glass refractive index to obtain a first glass optical element contour curve equation; determining first compensating molding mold parameters based on the first glass optical element contour curve equation; constructing a surface error compensation model based on the predicted surface shape error and the first compensating glass optical element contour curve equation; determining a compensation factor based on the surface error compensation model; performing surface error compensation on the first compensating molding mold parameters based on the compensation factor to obtain the compensated molding mold parameters.

[0012] Optionally, in the glass optical element molding mold surface-optical error compensation method according to the present invention, the first compensating molding mold parameters are compensated for surface error based on the compensation factor to obtain the compensated molding mold parameters, including: compensating the first compensating glass optical element contour curve equation based on the compensation factor to obtain the second compensating glass optical element contour curve equation; based on the second compensating glass optical element contour curve equation, determining the compensated molding mold parameters.

[0013] Optionally, in the glass optical element molding die surface shape-optical error compensation method according to the present invention, a creep testing method based on constant pressure stress, micro-deformation, low friction perturbation axial compression is used to obtain the creep displacement of the glass, including: grinding and polishing the surfaces of the glass to be tested, the sapphire upper substrate and the sapphire lower substrate respectively, and clamping the polished glass between the sapphire upper substrate and the sapphire lower substrate to form a test module, and placing the test module at the center position of the test platform of the test device; performing a creep testing method based on constant pressure stress, micro-deformation, low friction perturbation axial compression by the test device, including: contacting a measuring probe with the upper surface of the sapphire upper substrate, heating the glass by an infrared or electromagnetic heating device to heat the glass to a test temperature, and keeping it warm for a predetermined time; applying a vertical load on the sapphire upper substrate by a load applying device and a parallel guide system; and obtaining the creep displacement of the glass at the test temperature by a high-precision displacement sensor.

[0014] Optionally, in the glass optical element molding mold surface shape-optical error compensation method according to the present invention, the high-temperature viscoelastic parameters of the glass are determined based on the creep displacement, including: constructing a stress relaxation model based on the creep displacement, and determining the high-temperature viscoelastic parameters of the glass based on the stress relaxation model; wherein the high-temperature viscoelastic parameters of the glass include shear modulus and shear stress relaxation time.

[0015] Optionally, in the glass optical element molding mold surface shape-optical error compensation method according to the present invention, the glass optical element is a glass aspheric lens, a double-sided aspheric lens, an aspheric array or a cylindrical aspheric array.

[0016] Optionally, in the glass optical element molding die surface shape-optical error compensation method according to the present invention, constructing an initial glass optical element profile curve equation includes: constructing an initial glass optical element profile curve equation using optical design software.

[0017] Optionally, in the glass optical element molding mold surface shape-optical error compensation method according to the present invention, the volume change-refractive index model of the glass optical element is as follows:

[0018]

[0019] n c =n+Δn

[0020] Where V0 represents the initial volume of the preformed glass optical element before annealing and cooling, V c represents the final volume of the simulated glass optical element after annealing and cooling; n represents the initial refractive index of the preformed glass optical element before annealing and cooling, n c Represents the final refractive index of the simulated glass optical element after annealing and cooling.

[0021] According to one aspect of the present invention, a glass optical element molding die surface shape-optical error compensation device is provided, which is deployed in a computing device, and the device comprises: an acquisition unit, which is suitable for obtaining the creep displacement of the glass by using a creep test method based on constant pressure stress micro-deformation low-friction disturbance axial compression, and determining the high-temperature viscoelastic parameters of the glass based on the creep displacement; a construction unit, which is suitable for constructing an initial glass optical element profile curve equation, and determining initial molding die parameters based on the initial glass optical element profile curve equation; an establishment unit, which is suitable for establishing the glass preform under force-heat coupling based on the initial molding die parameters. a simulation model of the glass preform; a simulation prediction unit, adapted to utilize the simulation prediction model to simulate the molding process based on the initial molding die parameters, the glass preform simulation model and the glass high-temperature viscoelastic parameters to obtain a simulated glass optical element, and to predict the surface error and optical error of the simulated glass optical element to obtain the corresponding predicted surface error and predicted optical error; a compensation unit, adapted to compensate the initial molding die parameters based on the predicted surface error and predicted optical error to obtain compensated molding die parameters, so as to manufacture a compensated molding die based on the compensated molding die parameters.

[0022] Optionally, in the surface shape-optical error compensation device for a glass optical element molding mold according to the present invention, the compensated molding mold is used to perform a molding test to obtain a test surface shape error and a test optical error of the glass optical element after the test; the device further comprises:

[0023] A determination unit, adapted to determine a test surface shape error and a test optical error of a post-test glass optical element obtained by performing a compression molding test using the post-compensation compression mold;

[0024] A judging unit, adapted to judge whether the test surface shape error and the test optical error are respectively less than a surface shape error threshold and an optical error threshold:

[0025] A correction unit, wherein if the test surface error is not less than a surface error threshold or the test optical error is not less than an optical error threshold, the correction unit is adapted to correct the simulation prediction model based on the test surface error and the test optical error of the glass optical element after the test to obtain the corrected simulation prediction model;

[0026] The simulation prediction unit is further adapted to: using the modified simulation prediction model, based on the initial molding die parameters, the glass preform simulation model and the glass high-temperature viscoelastic parameters, simulate the molding process to obtain a simulated glass optical element, and predict the surface error and optical error of the simulated glass optical element to obtain a corresponding predicted surface error and predicted optical error;

[0027] The compensation unit is also suitable for: compensating the initial molding mold parameters based on the predicted surface error and the predicted optical error to obtain compensated molding mold parameters, so as to manufacture a compensated molding mold based on the compensated molding mold parameters, until the test surface error and the test optical error of the glass optical element after the test are respectively less than the surface error threshold and the optical error threshold, and the simulation prediction model corrected this time is used as the final simulation prediction model.

[0028] According to one aspect of the present invention, there is provided a computing device, comprising: at least one processor; and a memory storing program instructions, wherein the program instructions are configured to be suitable for execution by the at least one processor, and the program instructions include instructions for executing the glass optical element molding mold surface shape-optical error compensation method as described above.

[0029] According to one aspect of the present invention, a computer program product is provided, comprising a computer program / instruction, wherein the computer program / instruction implements the method as described above when executed by a processor.

[0030] According to one aspect of the present invention, a readable storage medium storing program instructions is provided. When the program instructions are read and executed by a computing device, the computing device executes the glass optical element molding mold surface shape-optical error compensation method as described above.

[0031] According to the technical solution of the present invention, a method for compensating the surface shape-optical errors of a glass optical element molding die is provided. A creep test method based on constant pressure stress, micro-deformation, low-friction disturbance axial compression is used to obtain the high-temperature viscoelastic parameters of the glass. The initial molding die parameters are determined by constructing an equation for the initial glass optical element contour curve, and a simulation model of a glass preform under force-heat coupling is established. Then, a simulation prediction model is used to simulate and predict the surface shape errors and optical errors of the glass optical element based on the initial molding die parameters, the glass preform simulation model, and the high-temperature viscoelastic parameters of the glass. The predicted surface shape errors and optical errors compensate for the initial molding die parameters, and then a compensated molding die can be manufactured based on the compensated molding die parameters. According to the technical solution of the present invention, firstly, a creep test method based on constant pressure stress micro-deformation low friction disturbance axial compression can be used to obtain high-precision high-temperature viscoelastic parameters of glass, and then a simulation prediction model can be used to accurately simulate and predict the surface error and optical error of the glass optical element formed by compression molding; secondly, based on the predicted surface error and optical error, the surface error and optical error of the compression mold parameters can be compensated at the same time, and a compression mold after surface-optical error compensation can be used to obtain a high-precision, high-optical performance glass optical element by one-time compression molding. On the one hand, the problem of poor optical performance of glass optical elements caused by not considering optical errors is solved, and the optical performance of glass optical elements is improved. On the other hand, repeated mold repair is avoided, thereby reducing the number of compensation times for the compression mold and reducing the manufacturing cost and cycle of the compression mold.

[0032] In addition, the present invention can also continuously correct the simulation prediction model based on the test surface shape error and test optical error of the glass optical element after the test, so that the compensation accuracy of the simulation prediction model can be continuously improved. The final simulation prediction model obtained after multiple corrections can achieve a higher-precision simulation prediction of the surface shape error and optical error of the glass optical element, thereby achieving accurate compensation of the molding die parameters and improving the compensation accuracy.

[0033] In addition, the glass optical element molding mold surface shape-optical error compensation method according to the present invention is suitable for compensation of glass optical elements such as conventional glass aspheric lenses, double-sided aspheric lenses, aspheric arrays or cylindrical aspheric arrays of different scales. It has wide adaptability, and the surface shape accuracy, optical performance and consistency of the molded glass optical elements can be improved based on the compensation. It meets the needs of aerospace, biomedicine, national defense and military industry, 5G+AI, new energy vehicles and other industries for mass production and efficient manufacturing of glass optical elements, and has broad application prospects.

[0034] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to achieve the above and related purposes, some illustrative aspects are described herein in conjunction with the following description and accompanying drawings, which indicate various ways in which the principles disclosed herein can be practiced, and all aspects and their equivalents are intended to fall within the scope of the claimed subject matter. By reading the following detailed description in conjunction with the accompanying drawings, the above and other purposes, features and advantages of the present invention will become more apparent. Throughout the present invention, the same reference numerals generally refer to the same parts or elements.

[0036] Figure 1 A schematic diagram of a computing device 100 provided according to an embodiment of the present invention is shown;

[0037] Figure 2 A schematic flow chart of a method 200 for compensating surface shape and optical error of a glass optical element molding die according to an embodiment of the present invention is shown;

[0038] Figure 3 A schematic diagram showing the principle of a testing device 300 provided according to an embodiment of the present invention is shown;

[0039] Figure 4 A schematic diagram showing the principle comparison between the traditional large strain friction perturbation creep test and the constant pressure stress low friction perturbation creep test;

[0040] Figure 5 A schematic flow chart of a method 500 for compensating surface shape-optical errors of a glass optical element molding mold provided according to some embodiments of the present invention is shown;

[0041] Figure 6 A schematic diagram showing a predicted surface shape error of a simulated glass optical element (aspherical lens) according to a specific embodiment of the present invention is shown;

[0042] Figure 7 A schematic diagram showing the surface error of a glass optical element molded by using an initial molding mold corresponding to uncompensated initial molding mold parameters according to a specific embodiment of the present invention;

[0043] Figure 8 A schematic diagram showing the surface error of a glass optical element molded by using a compensated molding mold corresponding to the compensated molding mold parameters according to a specific embodiment of the present invention;

[0044] Fig. 9 A schematic diagram of a glass optical element molding mold surface shape-optical error compensation device 900 provided according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0045] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0046] According to the existing ultra-precision compression molding technology for glass optical components, on the one hand, optical error compensation for the compression mold is not taken into consideration, resulting in poor optical performance of the glass optical components obtained by compression molding. On the other hand, the mold is compensated and corrected through the surface error of the optical component obtained through the compression test, which requires repeated tests to correct the mold, resulting in problems such as a large number of corrections, high costs, and long cycles.

[0047] In order to solve the above technical problems, the present invention proposes a method for compensating the surface shape-optical error of a glass optical element molding die used in the field of ultra-precision molding. Firstly, a creep test method based on constant pressure stress, micro-deformation, low-friction disturbance, axial compression can be used to obtain high-precision glass high-temperature viscoelastic parameters, and then a simulation prediction model can be used to accurately simulate and predict the surface shape error and optical error of the molded glass optical element; secondly, based on the predicted surface shape error and optical error, the molding die parameters can be simultaneously compensated for the surface shape error and optical error. Through the molding die after the surface shape-optical error compensation, a high-precision, high-optical performance glass optical element can be obtained by one-time molding. On the one hand, the problem of poor optical performance of glass optical elements caused by not considering optical errors is solved, and the optical performance of glass optical elements is improved. On the other hand, repeated mold repair is avoided, thereby reducing the number of compensation times for the molding die, and reducing the manufacturing cost and cycle of the molding die.

[0048] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0049] Figure 1 FIG. 1 is a schematic diagram of a computing device 100 provided according to an embodiment of the present invention. Figure 1As shown, in a basic configuration, the computing device 100 includes at least one processing unit 102 and a system memory 104. According to one aspect, depending on the configuration and type of the computing device, the processing unit 102 can be implemented as a processor. The system memory 104 includes, but is not limited to, volatile storage (e.g., random access memory), non-volatile storage (e.g., read-only memory), flash memory, or any combination of such memories. According to one aspect, the system memory 104 includes an operating system 105.

[0050] According to one aspect, operating system 105 is suitable for controlling the operation of computing device 100, for example. Furthermore, examples are practiced in conjunction with graphics libraries, other operating systems, or any other application programs, and are not limited to any particular application or system. Figure 1 The basic configuration is shown in FIG. 1 by those components within the dashed lines. According to one aspect, computing device 100 has additional features or functionality. For example, according to one aspect, computing device 100 includes additional data storage devices (removable and / or non-removable), such as magnetic disks, optical disks, or tapes. Such additional storage Figure 1 1 is illustrated by a removable storage device 109 and a non-removable storage device 110.

[0051] As stated above, according to one aspect, a program module 103 is stored in the system memory 104. According to one aspect, the program module 103 may include one or more application programs, and the present invention does not limit the type of application program, for example, the application program may include: email and contact application programs, word processing application programs, spreadsheet application programs, database application programs, slide show application programs, drawing or computer-aided application programs, web browser application programs, etc.

[0052] According to one aspect, the program module 103 may include multiple program instructions suitable for executing the glass optical element molding mold surface shape-optical error compensation method of the present invention, so that the computing device 100 is configured to execute the glass optical element molding mold surface shape-optical error compensation method of the present invention.

[0053] According to one aspect, the program module 103 may include a glass optical element molding mold surface shape-optical error compensation device 900, and the glass optical element molding mold surface shape-optical error compensation device 900 may be configured to execute the glass optical element molding mold surface shape-optical error compensation method of the present invention.

[0054] According to one aspect, the examples may be practiced on a circuit comprising discrete electronic components, a packaged or integrated electronic chip containing logic gates, a circuit utilizing a microprocessor, or a single chip containing electronic components or a microprocessor. Figure 1 Each or many components shown in can be integrated into a system on a chip (SOC) on a single integrated circuit to practice examples. According to one aspect, such a SOC device may include one or more processing units, a graphics unit, a communication unit, a system virtualization unit, and various application functions, all of which are integrated (or "burned") into a chip substrate as a single integrated circuit. When operated via SOC, the functions described in this article can be operated via a dedicated logic integrated with other components of the computing device 100 on a single integrated circuit (chip). Embodiments of the present invention can also be practiced using other technologies capable of performing logical operations (such as AND, OR, and NOT), including but not limited to mechanical, optical, fluid, and quantum technologies. In addition, embodiments of the present invention can be practiced in a general-purpose computer or in any other circuit or system.

[0055] According to one aspect, the computing device 100 may also have one or more input devices 112, such as a keyboard, a mouse, a pen, a voice input device, a touch input device, etc. Output devices 114 may also be included, such as a display, a speaker, a printer, etc. The aforementioned devices are examples and other devices may also be used. The computing device 100 may include one or more communication connections 116 that allow communication with other computing devices 118. Examples of suitable communication connections 116 include, but are not limited to: RF transmitter, receiver and / or transceiver circuits; Universal Serial Bus (USB), parallel and / or serial ports.

[0056] The term computer-readable medium as used herein includes computer storage media. Computer storage media may include volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (e.g., computer-readable instructions, data structures, or program modules 103). System memory 104, removable storage device 109, and non-removable storage device 110 are all examples of computer storage media (i.e., memory storage). Computer storage media may include random access memory (RAM), read-only memory (ROM), electrically erasable read-only memory (EEPROM), flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical storage, cassettes, tapes, disk storage or other magnetic storage devices, or any other products that can be used to store information and can be accessed by computing device 100. According to one aspect, any such computer storage medium can be a part of computing device 100. Computer storage media do not include carrier waves or other propagated data signals.

[0057] According to one aspect, communication media is implemented by computer readable instructions, data structures, program modules 103, or other data in a modulated data signal (e.g., a carrier wave or other transport mechanism), and includes any information delivery media. According to one aspect, the term "modulated data signal" describes a signal that has one or more characteristics set or changed in such a manner as to encode information in the signal. By way of example and not limitation, communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, radio frequency (RF), infrared, and other wireless media.

[0058] In an embodiment according to the present invention, the computing device 100 is configured to execute the surface shape-optical error compensation method of the glass optical element molding mold of the present invention. The computing device 100 includes one or more processors, and one or more readable storage media storing program instructions. When the program instructions are configured to be executed by one or more processors, the computing device executes the surface shape-optical error compensation method of the glass optical element molding mold in the embodiment of the present invention. By executing the surface shape-optical error compensation method of the glass optical element molding mold in the embodiment of the present invention, the surface shape error and optical error compensation of the molding mold of the glass optical element (used for ultra-precision molding of glass optical elements) can be performed.

[0059] Figure 2 A schematic flow chart of a method 200 for compensating surface shape and optical error of a glass optical element molding mold provided according to an embodiment of the present invention is shown. The method 200 for compensating surface shape and optical error of a glass optical element molding mold can be executed in a computing device (eg, the aforementioned computing device 100).

[0060] In an embodiment of the present invention, the molding die is used for ultra-precision molding of glass optical elements. The glass optical element may specifically be a conventional glass aspheric lens, a double-sided aspheric lens, an aspheric array, or a cylindrical aspheric array. In other words, the surface shape-optical error compensation method 200 for molding die of glass optical element according to the present invention can perform surface shape error compensation and optical error compensation on the molding die of glass optical elements such as conventional glass aspheric lens, double-sided aspheric lens, aspheric array, or cylindrical aspheric array.

[0061] like Figure 2 As shown, the glass optical element molding mold surface shape-optical error compensation method 200 includes steps 210-250.

[0062] Figure 3 A schematic diagram showing the principle of a method for compensating surface shape-optical errors of a glass optical element molding mold provided according to an embodiment of the present invention is shown.

[0063] The following will be combined Figure 2 and Figure 3 Steps 210 to 250 will be described below.

[0064] First, in step 210, a creep test method based on constant pressure stress micro-deformation low friction disturbance axial compression can be used to obtain the creep displacement of glass (i.e., glass used to prepare glass optical elements), and the high temperature viscoelastic parameters of the glass can be determined based on the creep displacement. In this way, high-precision high temperature viscoelastic parameters of the glass can be obtained.

[0065] Subsequently, in step 220, an initial glass optical component profile curve equation may be constructed, and initial molding die parameters may be determined based on the initial glass optical component profile curve equation.

[0066] In an embodiment of the present invention, the glass optical element can be designed using optical design software to construct an initial glass optical element profile curve equation. Subsequently, initial molding die parameters can be determined based on the initial glass optical element profile curve equation.

[0067] Next, in step 230, a simulation model of the glass preform under the force-heat coupling effect may be established based on the initial molding die parameters.

[0068] It should be noted that the glass preform simulation model is a digital expression of the glass preform. The glass preform is a glass material used for compression molding to obtain a glass optical element. That is, in the embodiment of the present invention, the glass optical element can be obtained by compression molding the glass preform.

[0069] Afterwards, the above-mentioned initial molding die parameters, glass preform simulation model, and glass high-temperature viscoelastic parameters may be input into the simulation prediction model.

[0070] Next, in step 240, the simulation prediction model can be used to simulate the compression molding process (i.e., the process of compression molding the glass preform to obtain a glass optical element) based on the initial molding mold parameters, the glass preform simulation model and the glass high-temperature viscoelastic parameters to obtain a simulated glass optical element, and predict the surface error and optical error of the simulated glass optical element to obtain the corresponding predicted surface error and predicted optical error.

[0071] It should be noted that the predicted surface error is the deviation between the simulated glass optical element profile and the initial glass optical element profile.

[0072] In an embodiment of the present invention, the compression molding process includes a compression molding stage and an annealing cooling stage. The specific process of simulating the compression molding process using a simulation prediction model based on initial compression mold parameters, a glass preform simulation model, and glass high-temperature viscoelastic parameters is as follows:

[0073] First, the molding process conditions are determined. The molding process conditions may include an initial temperature, a target temperature, and a predetermined molding pressure. Subsequently, based on the initial molding mold parameters, the glass preform simulation model, and the glass high-temperature viscoelastic parameters, and according to the molding process conditions, the molding stage of the glass preform is simulated to obtain a preformed glass optical element as a molding result. Specifically, the process of simulating the molding stage of the glass preform according to the molding process conditions is as follows: the glass preform simulation model is heated from the initial temperature to the target temperature, and then a predetermined molding pressure is applied thereto for molding. After the glass preform simulation model is filled, the predetermined molding pressure is removed, and a holding pressure less than the predetermined molding pressure is applied for holding pressure to obtain a molding result. Furthermore, the molding result (preformed glass optical element) is used as the initial condition of the annealing cooling stage to simulate the annealing cooling stage to obtain a simulated glass optical element.

[0074] Finally, in step 250, the initial molding die parameters can be compensated based on the predicted surface shape error and the predicted optical error to obtain compensated molding die parameters, so as to manufacture the compensated molding die based on the compensated molding die parameters. It should be understood that the compensated molding die parameters can be used as processing parameters of the compensated molding die for manufacturing the compensated molding die.

[0075] According to the surface-optical error compensation method of a glass optical element molding die provided by an embodiment of the present invention, firstly, a creep test method based on constant pressure stress micro-deformation low-friction disturbance axial compression can be used to obtain high-precision glass high-temperature viscoelastic parameters, and then a simulation prediction model can be used to accurately simulate and predict the surface error and optical error of the molded glass optical element; secondly, based on the predicted surface error and optical error, the molding die parameters can be simultaneously compensated for the surface error and optical error, and a high-precision, high-optical-performance glass optical element can be obtained by one-time molding through a molding die after surface-optical error compensation. On the one hand, the problem of poor optical performance of glass optical elements caused by not considering optical errors is solved, and the optical performance of glass optical elements is improved. On the other hand, repeated mold repairs are avoided, thereby reducing the number of compensation times for the molding die, and reducing the manufacturing cost and cycle of the molding die.

[0076] In some embodiments, the glass optical element is an aspheric glass optical element. Accordingly, the molding mold parameters include a plurality of aspheric coefficients.

[0077] In some embodiments, the creep test method based on constant pressure stress, micro deformation, low friction perturbation axial compression in step 210 can be performed in the test device 300. That is, the creep test method based on constant pressure stress, micro deformation, low friction perturbation axial compression can be performed by the test device 300 to perform a creep test on the glass.

[0078] Figure 3 A schematic diagram of the principle of a testing device 300 provided according to an embodiment of the present invention is shown.

[0079] like Figure 3 As shown, the test device 300 is used to perform a creep test based on constant pressure stress micro-deformation low friction disturbance axial compression on an optical glass 305. The test device 300 includes: a test housing 301, an infrared or electromagnetic heating device (including a first infrared or electromagnetic heating device 302 and a second infrared or electromagnetic heating device 306), a measuring probe 303, a sapphire upper substrate 304, a sapphire lower substrate 307, a test platform 309, a sample holder 310, a support frame 311, a constant temperature test unit 312, a high-precision displacement sensor 313, a parallel guide system 314, a load application device 315, and a calibration weight 316.

[0080] The first infrared or electromagnetic heating device 302 , the second infrared or electromagnetic heating device 306 , the first infrared or electromagnetic heating device 302 , and the second infrared or electromagnetic heating device 306 may all be arranged in the test housing 301 .

[0081] The test platform 309 and the sample holder 310 can be installed together through mechanical assembly and installed on the support frame 311. The test platform 309 is installed on the upper end of the sample holder 310, and the upper end of the sample holder 310 and the test platform 309 extend into the test housing 301. The upper part of the measurement probe 303 extends into the test housing 301.

[0082] The high-precision displacement sensor 313, the parallel guide system 314 of the full bearing, and the load applying device 315 are all installed in the constant temperature test unit 312, so as to avoid the influence of temperature on the sensor unit. It should be noted that before the creep test based on constant pressure stress micro-deformation low friction disturbance axial compression is performed on the glass by the test device 300, the test device 300 can be calibrated in advance by the calibration weight 316.

[0083] In some embodiments, the creep displacement of glass is obtained in the following manner using a creep testing method based on constant pressure stress micro-deformation low friction disturbance axial compression.

[0084] First, the surfaces of the optical glass 305 to be tested (ie, glass used to prepare glass optical elements), the sapphire upper substrate 304 and the sapphire lower substrate 307 may be ground and polished respectively to form ultra-precision smooth surfaces.

[0085] Subsequently, the polished optical glass 305 is clamped between the sapphire upper substrate 304 and the sapphire lower substrate 307 to form a test module, and the test module is placed at the center of the test platform 309 of the test device 300 .

[0086] Furthermore, the creep test method based on constant pressure stress micro-deformation low friction disturbance axial compression can be performed by the test device 300, specifically as follows: the measuring probe 303 is contacted with the upper surface of the sapphire substrate 304. Afterwards, the optical glass 305 can be heated by an infrared or electromagnetic heating device, and the heating temperature of the optical glass 305 is detected by a thermocouple temperature sensor 308, so as to heat the optical glass 305 to the optical glass yield point temperature (test temperature), and keep the temperature for a predetermined time. Then, a small load is applied to the sapphire substrate 304 by a load applying device 315, and the load applied to the sapphire substrate 304 is ensured to be in the vertical direction by a full-bearing parallel guide system 314, that is, a small load in the vertical direction is applied to the sapphire substrate 304 by the load applying device 315 and the parallel guide system 314. While applying the load, the creep displacement of the optical glass 305 at the test temperature can be detected and obtained by a high-precision displacement sensor 313.

[0087] It should be noted that the above-mentioned method of applying load can ensure that the axial compressive stress of the glass is constant and micro-deformed, so that the cross-section of the glass remains unchanged during the axial compression process, achieving low friction disturbance, which can be approximately equivalent to frictionless disturbance, thereby realizing creep testing of the glass (optical glass 305) based on constant compressive stress, micro-deformation, low friction disturbance and axial compression.

[0088] Based on this, during the above creep test of the glass (optical glass 305), the creep displacement of the glass with low friction disturbance can be obtained by the high-precision displacement sensor 313. Here, the high-precision displacement sensor 313 can realize micron-level creep displacement detection to obtain high-precision creep displacement of the glass (optical glass 305).

[0089] In some embodiments, the computing device 100 can be communicatively connected to the high-precision displacement sensor 313, and the high-precision displacement sensor 313 can send the creep displacement of the glass detected by it to the computing device 100, that is, the computing device 100 can obtain the creep displacement of the glass from the high-precision displacement sensor 313.

[0090] Figure 4 A schematic diagram showing the principle comparison between the traditional large strain friction perturbation creep test and the constant pressure stress low friction perturbation creep test.

[0091] It needs to be further explained that if Figure 4As shown, when the glass is tested based on the creep test method of constant pressure stress, micro-deformation, low friction disturbance, axial compression, only a small load is applied, the glass undergoes micro-deformation, and due to the ultra-smooth surface between the sapphire upper substrate 304, the sapphire lower substrate 307 and the optical glass 305, the friction is close to zero (μ≈0), so the shape of the optical glass can always remain cylindrical, and the cross-sectional area remains unchanged. At this time, the compressive stress on the glass is constant.

[0092] However, in the traditional large-load and large-strain friction perturbation creep test, due to the existence of friction (μ>0), the strain area of ​​the glass during the test is drum-shaped, and the cross-sectional area increases relative to that before the test, and the compressive stress decreases with the increase in test time, resulting in a large error in the creep displacement obtained from the test. Friction needs to be considered and creep needs to be corrected, but there will also be cumulative errors in the friction test process, which will affect the accuracy of the creep displacement solution.

[0093] In some embodiments, in step 210, after obtaining the creep displacement of the glass using a creep test method based on constant pressure stress micro-deformation low friction perturbation axial compression, a stress relaxation model can be constructed based on the creep displacement, and the high temperature viscoelastic parameters of the glass can be determined based on the stress relaxation model. The viscoelastic parameters of the glass include the shear modulus G(t) and the shear stress relaxation time τ i .

[0094] The specific process of constructing the stress relaxation model based on creep displacement is as follows.

[0095] First, the compressive stress σ on the glass can be z and the initial height of the glass L0, the real-time height of the glass during creep compression L z (t), the creep compliance J(t) of the glass creep compression is calculated. Specifically, the creep compliance can be calculated according to the following formula (1):

[0096] J(t)=-ln(L z (t) / L0) / σ z (1)

[0097] In the above formula, J(t) represents the creep compliance of glass creep compression, σ z represents the compressive stress on the glass, L0 represents the initial height of the glass, L z (t) represents the real-time height of the glass during the creep compression process.

[0098] In creep compression based on constant compressive stress, the relationship between the shear modulus G(t) and creep compliance J(t) of glass after Laplace transformation can be expressed as the following equation (2):

[0099]

[0100] In the above formula, represents the relaxation modulus. Furthermore, the Kelvin-Voigt model can be used to fit the creep compliance test data. The creep compliance function J z (t) can be expressed as the following formula (3):

[0101]

[0102] Where E is the temperature-dependent Young's modulus. E0 is the Young's modulus of the glass at room temperature, E i and λ i are the elastic modulus relaxation times for each Kelvin component, respectively.

[0103] By considering the creep compliance function J z After Laplace transformation of (t), the relaxation modulus can be obtained and The relationship between is as follows (4):

[0104]

[0105] According to the above relaxation modulus and By performing an inverse Laplace transform on the relationship between , we can get the shear modulus G(t) of the glass. The shear modulus G(t) of the glass can be expressed in the form of a Prony series:

[0106]

[0107] τ i =η i / G i (6)

[0108] In the above formula, τ i is the shear stress relaxation time, G i is the shear modulus component, G ∞ is the long-term shear modulus.

[0109] The instantaneous shear modulus G0 can be expressed as:

[0110]

[0111] Thus, a stress relaxation model can be obtained, including the above equations (1) to (7).

[0112] Furthermore, by fitting the stress relaxation model, high-precision glass viscoelastic parameters can be solved. Glass viscoelastic parameters include shear modulus G(t) and shear stress relaxation time τ i .

[0113] In some embodiments, during the simulation prediction process using the simulation prediction model, the predicted surface error and predicted optical error of the simulated glass optical element may be predicted in the following manner.

[0114] For the predicted surface shape error of the simulated glass optical element, the interpolation method can be used to fit the node coordinates of the simulated glass optical element and the node coordinates of the initial pressing mold corresponding to the initial pressing mold parameters to determine the predicted surface shape error of the simulated glass optical element (i.e., the deviation between the contour of the simulated glass optical element and the contour of the initial glass optical element). Specifically, the nodes on the simulated glass optical element and the nodes on the initial pressing mold corresponding to the initial pressing mold parameters can be extracted along the radial direction and fitted to calculate the predicted surface shape error of the simulated glass optical element.

[0115] It should be noted that the residual stress of the glass optical element during the annealing cooling stage will affect its optical properties (such as refractive index). Therefore, the predicted optical error of the simulated glass optical element includes the glass refractive index of the simulated glass optical element, and the predicted optical error can be used as the predicted glass refractive index of the simulated glass optical element.

[0116] Specifically, for predicting optical errors of simulated glass optical elements, a volume change-refractive index model of the glass optical element during the annealing and cooling stage can be first constructed. The volume change-refractive index model of the glass optical element is used to simulate the volume and refractive index changes of the glass optical element during the annealing and cooling stage.

[0117] Among them, the volume change-refractive index model of glass optical elements is as follows:

[0118]

[0119] n c =n+Δn (9)

[0120] In the above formula, V0 represents the initial volume of the preformed glass optical element before annealing and cooling, V c represents the final volume of the simulated glass optical element after annealing and cooling. n represents the initial refractive index of the preformed glass optical element before annealing and cooling, n c Represents the final refractive index of the simulated glass optical element after annealing and cooling.

[0121] Furthermore, by solving the volume change-refractive index model of the glass element, the final refractive index (n c ), and the final refractive index is used as the glass refractive index of the simulated glass optical element. Here, the glass refractive index of the simulated glass optical element, that is, the glass refractive index of the simulated glass optical element coupled with residual stress, can be used as the predicted optical error of the simulated glass optical element.

[0122] In step 250, the specific method of compensating the initial molding die parameters based on the predicted surface shape error and the predicted optical error is as follows:

[0123] First, the initial glass optical element profile curve equation can be optically compensated based on the glass refractive index of the simulated glass optical element (i.e., predicted optical error) to obtain the first glass optical element profile curve equation after optical error compensation (i.e., the glass optical element profile curve equation after optical error compensation). Furthermore, the corresponding first compensation molding die parameters (i.e., the molding die parameters after optical error compensation) can be determined based on the first glass optical element profile curve equation.

[0124] Furthermore, surface error compensation can be performed based on the first glass optical element profile curve equation obtained after optical error compensation and the first compensation molding die parameters.

[0125] Specifically, a surface error compensation model can be constructed based on the predicted surface error and the first compensating glass optical element profile curve equation. Subsequently, a compensation factor can be determined based on the surface error compensation model. Furthermore, the surface error compensation can be performed on the first compensating molding die parameters based on the compensation factor to obtain the compensated molding die parameters.

[0126] Further, after determining the compensation factor, the first compensation glass optical element profile curve equation can be compensated based on the compensation factor to obtain the second compensation glass optical element profile curve equation. Then, the corresponding second compensation molding die parameters (i.e., compensated molding die parameters) can be determined based on the second compensation glass optical element profile curve equation.

[0127] In one embodiment, the glass optical element is an aspherical glass optical element. The specific method of constructing the surface error compensation model is as follows.

[0128] First, the aspheric equation of the aspheric glass optical element can be established as the profile curve equation of the glass optical element, as follows:

[0129]

[0130] Then, assuming that the compensation factor is α, the high-order coefficients of the second glass optical element profile curve equation obtained by compensating the first glass optical element profile curve equation based on the compensation factor α can be expressed as:

[0131]

[0132] In the above formula, A ia A is the coefficient of the higher order term of the profile curve equation of the second glass optical element obtained after compensation.ib are the coefficients of the first glass optical element profile equation.

[0133] In addition, the cone coefficient k and the inverse of the curvature radius c of the profile curve equation of the glass optical element can be expressed as:

[0134] k ia =k ib (1+α) i-1 ,i=1 (12)

[0135] c a =c b (1+α) (13)

[0136] In the above formula, k ia 、c a are the cone coefficient and curvature radius of the profile curve equation of the second glass optical element obtained after compensation. id 、c b are respectively the cone coefficient and the curvature radius of the profile curve equation of the first glass optical element.

[0137] Furthermore, by discretizing the first glass optical element profile curve equation and the second glass optical element profile curve equation within the effective diameter, the profile curve equation of the discrete point glass optical element after compensation at the maximum radius can be obtained as follows:

[0138]

[0139] The surface accuracy shrinkage deformation compensation of glass optical elements is:

[0140] PV 预补 =Z amax -Z bmax =PV sim -PV object (15)

[0141] In the above formula, Z amax , Z bmax They are the Z-axis height values ​​before and after compensation respectively. PVsim and PV object They are the predicted surface error obtained by simulation prediction and the target surface error that needs to be compensated.

[0142] Based on the above equations (10)-(15), the surface error compensation model can be obtained.

[0143] By solving the above-mentioned surface error compensation model, the value of the compensation factor α can be obtained. Then, the surface error compensation can be performed on the first compensation molding die parameters based on the compensation factor to obtain the compensated molding die parameters (aspheric parameters). Specifically, the first compensation glass optical element profile curve equation can be compensated based on the compensation factor to obtain the second compensation glass optical element profile curve equation, and the compensated molding die parameters can be determined based on the second compensation glass optical element profile curve equation.

[0144] It should be understood that the compensated molding die parameters are the molding die parameters obtained after optical error compensation and surface error compensation, and the compensated molding die parameters can be directly used as the processing parameters of the molding die.

[0145] also, Figure 5 A schematic flow chart of a method 500 for compensating surface shape and optical error of a glass optical element molding mold according to some embodiments of the present invention is shown. The method 500 may be executed in the aforementioned computing device 100.

[0146] like Figure 5 As shown, the glass optical element molding die surface shape-optical error compensation method 500 includes steps 510 to 580. Figure 5 Steps 510 to 580 will be described below.

[0147] Step 510: Using a creep test method based on constant pressure stress micro-deformation low friction disturbance axial compression, the creep displacement of glass (i.e., glass used to prepare glass optical elements) is obtained, and the high temperature viscoelastic parameters of the glass are determined based on the creep displacement. Thus, high-precision high temperature viscoelastic parameters of the glass can be obtained.

[0148] Step 520: construct an initial glass optical element profile curve equation, and determine initial molding die parameters based on the initial glass optical element profile curve equation.

[0149] In some embodiments, the glass optical element can be designed using optical design software to construct an initial glass optical element profile curve equation. Subsequently, initial molding mold parameters can be determined based on the initial glass optical element profile curve equation.

[0150] Step 530: Based on the initial molding die parameters, a simulation model of the glass preform under force-heat coupling is established.

[0151] It should be noted that the glass preform simulation model is a digital expression of the glass preform. The glass preform is a glass material used for compression molding to obtain a glass optical element. That is, in the embodiment of the present invention, the glass optical element can be obtained by compression molding the glass preform.

[0152] Afterwards, the above-mentioned initial molding die parameters, glass preform simulation model, and glass high-temperature viscoelastic parameters may be input into the simulation prediction model.

[0153] Step 540, using the simulation prediction model, based on the initial molding mold parameters, the glass preform simulation model and the glass high-temperature viscoelastic parameters, to simulate the molding process (i.e., the process of molding the glass preform to obtain the glass optical element) to obtain a simulated glass optical element, and predict the surface error and optical error of the simulated glass optical element to obtain the corresponding predicted surface error and predicted optical error.

[0154] It should be noted that the predicted surface error is the deviation between the simulated glass optical element profile and the initial glass optical element profile.

[0155] Step 550: Compensate the initial molding die parameters based on the predicted surface shape error and the predicted optical error to obtain compensated molding die parameters, so as to manufacture a compensated molding die based on the compensated molding die parameters.

[0156] It should be understood that the compensated post-molding mold parameters can be used as processing parameters of the compensated post-molding mold for manufacturing the compensated post-molding mold.

[0157] It should be noted that the compensated compression mold is used to perform compression molding tests to obtain the test surface shape error and test optical error of the glass optical element after the test.

[0158] After executing step 550, the computing device 100 may continue to execute the following steps 560 to 580:

[0159] Step 560: The computing device 100 may determine a test surface shape error and a test optical error of the tested glass optical element obtained by performing a compression molding test using the compensated compression mold.

[0160] Step 570: The computing device 100 determines whether the test surface shape error and the test optical error are less than the surface shape error threshold and the optical error threshold, respectively. If yes (it is determined that the above simulation prediction model meets the compensation accuracy requirement), the above simulation prediction model is directly used as the final simulation prediction model without executing the following steps. If no, continue to execute the following step 580.

[0161] Step 580: The computing device 100 corrects the simulation prediction model based on the experimental surface shape error and the experimental optical error of the glass optical element after the test to obtain the corrected simulation prediction model.

[0162] Next, based on the simulation prediction model corrected this time, the process may return to the above step 540 and iteratively execute steps 540 to 580.

[0163] Specifically, in step 540, the computing device 100 can use the corrected simulation prediction model to simulate the molding process based on the initial molding mold parameters, the glass preform simulation model and the glass high-temperature viscoelastic parameters to obtain a simulated glass optical element, and predict the surface error and optical error of the simulated glass optical element to obtain the corresponding predicted surface error and predicted optical error.

[0164] Subsequently, in step 550, the computing device 100 may compensate the initial molding mold parameters based on the predicted surface shape error and the predicted optical error to obtain compensated molding mold parameters, so as to manufacture a compensated molding mold based on the compensated molding mold parameters.

[0165] Next, in step 560, the computing device 100 may determine a test surface shape error and a test optical error of the tested glass optical element obtained by performing a compression molding test using the compensated compression mold.

[0166] In step 570, the computing device 100 determines whether the test surface shape error and the test optical error are less than the surface shape error threshold and the optical error threshold, respectively. If yes (it is determined that the simulation prediction model after this correction meets the compensation accuracy requirement), the simulation prediction model after this correction is used as the final simulation prediction model, and the following steps do not need to be performed. If not, continue to step 580.

[0167] In step 580, the computing device 100 corrects the simulation prediction model after the correction based on the experimental surface shape error and the experimental optical error of the glass optical element after the test, and obtains a second corrected simulation prediction model.

[0168] Iterative execution of the above steps 540 to 580 can continuously improve the compensation accuracy of the simulation prediction model until the test surface error and the test optical error of the glass optical element after the test are respectively less than the surface error threshold and the optical error threshold. The simulation prediction model after the last correction can be used as the final simulation prediction model, and the corresponding compensated molding mold parameters can be used as the final molding mold parameters. The final molding mold can be manufactured based on the final molding mold parameters.

[0169] It should be noted that the present invention can accurately predict the surface error and optical error of the glass optical element based on the final simulation prediction model, and then accurately compensate for the molding die parameters to improve the compensation accuracy.

[0170] A specific embodiment of the present invention is described below by taking K-PSFn214P optical glass as an example.

[0171] In a specific embodiment, a glass optical element can be prepared based on K-PSFn214P optical glass. The transition temperature Tg of K-PSFn214P optical glass is 427°C. In this embodiment, K-PSFn214P optical glass can be processed into a cylindrical shape with a diameter of φ5 mm and a height of 3 mm to obtain a K-PSFn214P glass preform, and the K-PSFn214P glass preform is used as the optical glass to be tested, and a creep test based on constant pressure stress micro-deformation low friction disturbance axial compression is performed in the test device 300.

[0172] In this specific embodiment, the diameters of the selected sapphire upper substrate and the sapphire lower substrate are both 10 mm and the thicknesses are both 1 mm.

[0173] Before the creep test, the upper and lower surfaces of the K-PSFn214P glass preform can be polished to Ra2nm in advance. In addition, the sapphire upper substrate and the sapphire lower substrate can be ultra-precision polished to an ultra-smooth surface.

[0174] Subsequently, the K-PSFn214P glass preform can be clamped between the sapphire upper substrate 304 and the sapphire lower substrate 307 to form a test module, and the test module is placed at the center of the test platform 309. Afterwards, the K-PSFn214P glass preform can be heated to test temperatures of 450°C, 460°C, and 470°C respectively by an infrared or electromagnetic heating device, and kept warm for 10 minutes. For each test temperature, a load of 0.2N can be applied to the sapphire upper substrate 304 by a load applying device 315, and the load applied to the sapphire upper substrate 304 is ensured to be in the vertical direction by a full-bearing parallel guide system 314. In addition, for each test temperature, while applying the load, the creep displacement (creep displacement of low friction disturbance) of the K-PSFn214P glass preform at the test temperature can be detected and recorded by a high-precision displacement sensor 313, that is, the creep displacement of the K-PSFn214P optical glass at the test temperature.

[0175] Furthermore, a stress relaxation model can be constructed based on the creep displacement of the K-PSFn214P optical glass at the test temperature, and the high temperature viscoelastic parameters (including shear modulus and shear stress relaxation time) of the K-PSFn214P optical glass at the test temperature can be determined based on the stress relaxation model. Here, the specific process of constructing the stress relaxation model can be referred to the description in the above embodiment, which will not be repeated here.

[0176] The high temperature viscoelastic parameters of K-PSFn214P optical glass at different test temperatures are shown in Table 1.

[0177] Table 1 High temperature viscoelastic parameters of K-PSFn214P optical glass at different test temperatures

[0178]

[0179]

[0180] In this specific embodiment, the glass optical element is an aspheric glass optical element (aspheric lens). The glass optical element can be designed using optical design software to construct an initial glass optical element profile curve equation. Subsequently, the initial molding die parameters can be determined based on the initial glass optical element profile curve equation. The effective diameter of the initial molding die is 19 mm. The initial molding die parameters include a plurality of aspheric coefficients, see Table 2.

[0181] Table 2 Initial molding die parameters

[0182]

[0183] In this specific embodiment, based on the initial molding die parameters, the diameter of the glass preform simulation model under the force-heat coupling effect is established to be φ14 mm. The material of the molding die is J05 tungsten carbide.

[0184] In the process of simulating the compression molding process using the simulation prediction model, the compression molding process conditions can be set as follows: initial temperature 25°C, target temperature 470°C, and predetermined mold pressure 779.31N. Specifically, the process of simulating the compression molding process is as follows: the glass preform simulation model is heated from 25°C to 470°C, and then a mold pressure of 779.31N is applied to it for compression molding. After the glass preform simulation model is filled, the predetermined mold pressure is removed, and a holding pressure less than the predetermined mold pressure is applied for holding pressure to obtain the compression molding result. Furthermore, the compression molding result is used as the initial condition of the annealing and cooling stage to simulate the annealing and cooling stage. After the simulation of the annealing and cooling stage is completed, a simulated glass optical element can be obtained.

[0185] Figure 6 A schematic diagram showing the predicted surface shape error of a simulated glass optical element (aspherical lens) according to a specific embodiment of the present invention is shown.

[0186] After the annealing cooling stage simulation is completed, Figure 6 As shown, the nodes on the simulated glass optical element and the nodes on the initial molding die can be extracted along the radial direction and fitted to calculate the profile deviation between the simulated glass optical element and the initial glass optical element at the maximum radius as the predicted surface error of the simulated glass optical element (aspherical lens). The predicted surface error calculated here is PV 7.187μm.

[0187] In this specific embodiment, the final refractive index of the simulated glass optical element can be calculated based on the volume change-refractive index model of the glass optical element in the annealing cooling stage. c =2.14607, and use the final refractive index as the glass refractive index (K-PSFn214P optical glass refractive index) to design optical error compensation for the initial glass optical element, that is, perform optical error compensation on the contour curve equation of the initial glass optical element based on the glass refractive index to obtain the contour curve equation of the first glass optical element after optical error compensation (that is, the contour curve equation of the glass optical element after optical error compensation), and then determine the corresponding first compensating molding mold parameters (that is, the molding mold parameters after optical error compensation) based on the contour curve equation of the first glass optical element.

[0188] Figure 7 A schematic diagram showing the surface error of a glass optical element molded by using an initial molding mold corresponding to uncompensated initial molding mold parameters according to a specific embodiment of the present invention is shown.

[0189] It should be noted that if Figure 7 As shown, under the same molding process conditions, the actual surface error PV of the glass optical element molded by the initial molding mold corresponding to the uncompensated initial molding mold parameters is 6.5134μm, which is close to the predicted surface error PV 7.187μm obtained by the above simulation prediction, thereby verifying the accuracy of the parameters input into the simulation prediction model.

[0190] In this specific embodiment, the predicted surface shape error ( PVsim ) is PV 7.187μm, and the target surface error (PV object ) is 0.7 μm. According to the surface error compensation model constructed above, the value of the compensation factor α can be calculated to be 0.001. Furthermore, the surface error compensation of the first compensating pressing mold parameters can be performed based on the compensation factor to obtain the compensated pressing mold parameters (aspheric parameters). Specifically, the first compensating glass optical element contour curve equation can be compensated based on the compensation factor to obtain the second compensating glass optical element contour curve equation, and the compensated pressing mold parameters can be determined based on the second compensating glass optical element contour curve equation.

[0191] The compensated molding die parameters include a plurality of correction coefficients (ie, compensated aspheric coefficients), as shown in Table 3.

[0192] Table 3 Compensated mold parameters

[0193]

[0194] Figure 8 A schematic diagram showing the surface error of a glass optical element molded by using a compensated molding mold corresponding to the compensated molding mold parameters according to a specific embodiment of the present invention is shown.

[0195] In a specific embodiment, after determining the post-compensation molding die parameters, a corresponding post-compensation molding die can be manufactured based on the post-compensation molding die parameters. Then, the post-compensation molding die can be used to perform a molding experiment under molding process conditions of a target temperature of 470°C and a predetermined molding pressure of 779.31N, and the surface shape accuracy of the test glass optical element (aspherical glass optical element) obtained by the molding experiment can be detected, such as Figure 8 As shown, the test surface error PV of the glass optical element after the test is 0.6186 μm. It can be seen that the compensated molding die designed by the present invention after surface shape-optical error compensation can obtain a glass optical element that meets the surface shape accuracy and optical performance requirements by one-time molding, avoiding repeated mold repairs.

[0196] According to the surface shape-optical error compensation method of the glass optical element molding die of the present invention, a creep test method based on constant pressure stress micro-deformation low friction disturbance axial compression is used to obtain the high-temperature viscoelastic parameters of the glass, and the initial molding die parameters are determined by constructing an initial glass optical element contour curve equation, and a glass preform simulation model under force-heat coupling is established. Then, a simulation prediction model is used to simulate and predict the surface shape error and optical error of the glass optical element based on the initial molding die parameters, the glass preform simulation model and the high-temperature viscoelastic parameters of the glass. The predicted surface shape error and optical error compensate for the initial molding die parameters, and then a compensated molding die can be manufactured based on the compensated molding die parameters. According to the technical solution of the present invention, firstly, a creep test method based on constant pressure stress micro-deformation low friction disturbance axial compression can be used to obtain high-precision high-temperature viscoelastic parameters of glass, and then a simulation prediction model can be used to accurately simulate and predict the surface error and optical error of the glass optical element formed by compression molding; secondly, based on the predicted surface error and optical error, the surface error and optical error of the compression mold parameters can be compensated at the same time, and a compression mold after surface-optical error compensation can be used to obtain a high-precision, high-optical performance glass optical element by one-time compression molding. On the one hand, the problem of poor optical performance of glass optical elements caused by not considering optical errors is solved, and the optical performance of glass optical elements is improved. On the other hand, repeated mold repair is avoided, thereby reducing the number of compensation times for the compression mold and reducing the manufacturing cost and cycle of the compression mold.

[0197] In addition, the present invention can also continuously correct the simulation prediction model based on the test surface shape error and test optical error of the glass optical element after the test, so that the compensation accuracy of the simulation prediction model can be continuously improved. The final simulation prediction model obtained after multiple corrections can achieve a higher-precision simulation prediction of the surface shape error and optical error of the glass optical element, thereby achieving accurate compensation of the molding die parameters and improving the compensation accuracy.

[0198] In addition, the glass optical element molding mold surface shape-optical error compensation method according to the present invention is suitable for compensation of glass optical elements such as conventional glass aspheric lenses, double-sided aspheric lenses, aspheric arrays or cylindrical aspheric arrays of different scales. It has wide adaptability, and the surface shape accuracy, optical performance and consistency of the molded glass optical elements can be improved based on the compensation. It meets the needs of aerospace, biomedicine, national defense and military industry, 5G+AI, new energy vehicles and other industries for mass production and efficient manufacturing of glass optical elements, and has broad application prospects.

[0199] Fig. 9 A schematic diagram of a glass optical element molding mold surface shape-optical error compensation device 900 provided according to an embodiment of the present invention is shown. The glass optical element molding mold surface shape-optical error compensation device 900 can be deployed in a computing device 100, and the glass optical element molding mold surface shape-optical error compensation device 900 can be configured to perform the glass optical element molding mold surface shape-optical error compensation method 200 and / or 500 of the present invention.

[0200] like Fig. 9 As shown, in an embodiment of the present invention, a glass optical element molding mold surface shape-optical error compensation device 900 includes an acquisition unit 910, a construction unit 920, an establishment unit 930, a simulation prediction unit 940, a compensation unit 950, a determination unit 960, a judgment unit 970 and a correction unit 980 which are sequentially communicated with each other.

[0201] The acquisition unit 910 may utilize a creep test method based on constant pressure stress micro-deformation low friction disturbance axial compression to acquire the creep displacement of the glass, and determine the high temperature viscoelastic parameters of the glass based on the creep displacement.

[0202] The construction unit 920 is used to construct an initial glass optical element profile curve equation, and determine initial molding die parameters based on the initial glass optical element profile curve equation.

[0203] The establishing unit 930 may establish a simulation model of the glass preform under the force-heat coupling effect based on the initial molding die parameters.

[0204] The simulation prediction unit 940 can use the simulation prediction model to simulate the molding process based on the initial molding mold parameters, the glass preform simulation model and the glass high-temperature viscoelastic parameters to obtain a simulated glass optical element, and predict the surface error and optical error of the simulated glass optical element to obtain the corresponding predicted surface error and predicted optical error.

[0205] The compensation unit 950 can compensate the initial molding mold parameters based on the predicted surface shape error and the predicted optical error to obtain compensated molding mold parameters, so as to manufacture the compensated molding mold based on the compensated molding mold parameters.

[0206] In addition, in some embodiments, the compensated compression mold is used to perform compression molding tests to obtain test surface shape errors and test optical errors of the glass optical element after the test.

[0207] The determination unit 960 may determine a test surface shape error and a test optical error of the tested glass optical element obtained by performing a compression molding test using the compensated compression mold.

[0208] The judgment unit 970 can judge whether the test surface shape error and the test optical error are respectively smaller than the surface shape error threshold and the optical error threshold.

[0209] If the test surface error is not less than the surface error threshold or the test optical error is not less than the optical error threshold, the correction unit 980 can correct the simulation prediction model based on the test surface error and the test optical error of the glass optical element after the test to obtain the corrected simulation prediction model.

[0210] The simulation prediction unit 940 can also use the revised simulation prediction model to simulate the molding process based on the initial molding mold parameters, the glass preform simulation model and the glass high-temperature viscoelastic parameters to obtain a simulated glass optical element, and predict the surface error and optical error of the simulated glass optical element to obtain the corresponding predicted surface error and predicted optical error.

[0211] The compensation unit 950 can also compensate the initial molding mold parameters based on the predicted surface shape error and the predicted optical error to obtain the compensated molding mold parameters, so as to manufacture the compensated molding mold based on the compensated molding mold parameters. When the test surface shape error and the test optical error of the glass optical element after the test are respectively less than the surface shape error threshold and the optical error threshold, the simulation prediction model after this correction can be used as the final simulation prediction model.

[0212] It should be noted that the specific execution logic of each unit can be found in the description of each step in the above method 200 / 500, which will not be repeated here.

[0213] The various techniques described herein may be implemented in combination with hardware or software, or a combination thereof. Thus, the method and apparatus of the present invention, or some aspects or parts of the method and apparatus of the present invention may be in the form of program codes (i.e., instructions) embedded in a tangible medium, such as a removable hard disk, a USB flash drive, a floppy disk, a CD-ROM, or any other machine-readable storage medium, wherein when the program is loaded into a machine such as a computer and executed by the machine, the machine becomes a device for practicing the present invention.

[0214] In the case where the program code is executed on a programmable computer, the mobile terminal generally includes a processor, a storage medium readable by the processor (including volatile and non-volatile memory and / or storage element), at least one input device, and at least one output device. The memory is configured to store the program code; the processor is configured to execute the glass optical element molding mold surface shape-optical error compensation method of the present invention according to the instructions in the program code stored in the memory.

[0215] By way of example and not limitation, readable media include readable storage media and communication media. Readable storage media stores information such as computer readable instructions, data structures, program modules or other data. Communication media generally embody computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transmission mechanism, and include any information transfer medium. Any combination of the above is also included within the scope of readable media.

[0216] In the description provided herein, algorithms and displays are not inherently related to any particular computer, virtual system or other device. Various general purpose systems can also be used together with the examples of the present invention. According to the above description, it is obvious that the structure required for constructing such systems. In addition, the present invention is not directed to any specific programming language either. It should be understood that various programming languages ​​can be utilized to implement the content of the present invention described herein, and the above description of specific languages ​​is for the purpose of disclosing the best mode of the present invention.

[0217] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0218] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof.

[0219] Those skilled in the art will appreciate that the modules or units or components of the devices in the examples disclosed herein may be arranged in the devices described in the embodiment, or alternatively may be located in one or more devices different from the devices in the examples. The modules in the foregoing examples may be combined into one module or may be divided into multiple submodules.

[0220] Unless otherwise specified, the use of ordinal numbers "first", "second", "third", etc. to describe common objects merely indicates that different instances of similar objects are involved and is not intended to imply that the objects so described must have a given order in time, space, order or in any other manner.

Claims

1. A method for compensating surface shape and optical error of a glass optical element molding die, executed in a computing device, comprising: Using a creep test method based on constant pressure stress micro-deformation low friction disturbance axial compression, the creep displacement of the glass is obtained, and the high temperature viscoelastic parameters of the glass are determined based on the creep displacement; Constructing an initial glass optical element profile curve equation, and determining initial molding die parameters based on the initial glass optical element profile curve equation; Based on the initial molding die parameters, a simulation model of the glass preform under force-heat coupling is established; Using a simulation prediction model, based on the initial molding die parameters, the glass preform simulation model and the glass high-temperature viscoelastic parameters, the molding process is simulated to obtain a simulated glass optical element, and the surface error and optical error of the simulated glass optical element are predicted to obtain corresponding predicted surface error and predicted optical error; The initial molding die parameters are compensated based on the predicted surface shape error and the predicted optical error to obtain compensated molding die parameters, so as to manufacture the compensated molding die based on the compensated molding die parameters.

2. The method of claim 1, wherein: The post-compensation compression mold is used to perform compression molding tests to obtain test surface shape errors and test optical errors of the glass optical element after the test; the method further comprises: Determine the test surface shape error and test optical error of the glass optical element after the test obtained by performing a compression molding test using the compensated compression mold; Determine whether the test surface shape error and the test optical error are respectively less than the surface shape error threshold and the optical error threshold. If not, then: Based on the experimental surface shape error and the experimental optical error of the glass optical element after the experiment, the simulation prediction model is corrected to obtain the corrected simulation prediction model; Using the revised simulation prediction model, based on the initial molding die parameters, the glass preform simulation model and the glass high-temperature viscoelastic parameters, the molding process is simulated to obtain a simulated glass optical element, and the surface error and optical error of the simulated glass optical element are predicted to obtain the corresponding predicted surface error and predicted optical error; The initial molding die parameters are compensated based on the predicted surface shape error and the predicted optical error to obtain compensated molding die parameters, so as to manufacture the compensated molding die based on the compensated molding die parameters; The above steps are iterated until the test surface error and the test optical error of the glass optical element after the test are respectively less than the surface error threshold and the optical error threshold, and the simulation prediction model corrected this time is used as the final simulation prediction model.

3. The method according to claim 1 or 2, wherein: The compression molding process includes a compression molding stage and an annealing cooling stage; Based on the initial molding die parameters, the glass preform simulation model and the glass high-temperature viscoelastic parameters, the molding process is simulated to obtain a simulated glass optical element, including: Determining molding process conditions, wherein the molding process conditions include initial temperature, target temperature, and predetermined molding pressure; Based on the initial molding mold parameters, the glass preform simulation model and the glass high-temperature viscoelastic parameters, and according to the molding process conditions, the molding stage of the glass preform is simulated to obtain an initial glass optical element as a molding result; The molding result is used as the initial condition of the annealing and cooling stage to simulate the annealing and cooling stage to obtain a simulated glass optical element.

4. The method according to any one of claims 1 to 3, wherein: The predicted optical error includes a glass refractive index; predicting the surface error and optical error of the simulated glass optical element to obtain the corresponding predicted surface error and predicted optical error, including: Using an interpolation method, fitting the node coordinates of the simulated glass optical element and the node coordinates of the initial pressing mold corresponding to the initial pressing mold parameters to determine the predicted surface shape error of the simulated glass optical element; Constructing a volume change-refractive index model of a glass optical element during an annealing and cooling stage, wherein the volume change-refractive index model of a glass optical element is used to simulate the volume and refractive index changes of the glass optical element during an annealing and cooling stage; The final refractive index of the simulated glass optical element is obtained by solving the volume change-refractive index model of the glass element, and the final refractive index is used as the glass refractive index of the simulated glass optical element.

5. The method of claim 4, wherein: The initial molding die parameters are compensated based on the predicted surface shape error and the predicted optical error to obtain compensated molding die parameters, including: Based on the glass refractive index, performing optical error compensation on the initial glass optical element profile curve equation to obtain a first glass optical element profile curve equation; Determining first compensation molding die parameters based on the first glass optical element profile curve equation; Based on the predicted surface error and the first compensating glass optical element profile curve equation, constructing a surface error compensation model; Based on the surface error compensation model, determining a compensation factor; The first compensating molding die parameters are compensated for surface errors based on the compensation factor to obtain the compensated molding die parameters.

6. The method of claim 5, wherein: Performing surface error compensation on the first compensation molding die parameter based on the compensation factor to obtain the compensated molding die parameter includes: Compensating the first compensating glass optical element profile curve equation based on the compensation factor to obtain a second compensating glass optical element profile curve equation; Based on the profile curve equation of the second compensating glass optical element, the parameters of the post-compensation molding die are determined.

7. The method according to any one of claims 1 to 6, wherein: The creep displacement of glass is obtained by using a creep test method based on constant pressure stress micro-deformation low friction disturbance axial compression, including: Grinding and polishing the surfaces of the glass to be tested, the sapphire upper substrate and the sapphire lower substrate respectively, clamping the polished glass between the sapphire upper substrate and the sapphire lower substrate to form a test module, and placing the test module at the center of the test platform of the test device; The creep test method based on constant pressure stress micro-deformation low friction disturbance axial compression is performed by the test device, which includes: placing a measuring probe in contact with the upper surface of the sapphire upper substrate, heating the glass by an infrared or electromagnetic heating device to heat the glass to a test temperature, and keeping the temperature for a predetermined time; Applying a vertical load on the sapphire substrate by means of a load applying device and a parallel guide system; The creep displacement of the glass at the test temperature is obtained by a high-precision displacement sensor.

8. The method according to any one of claims 1 to 7, wherein: Determining high temperature viscoelastic parameters of glass based on the creep displacement includes: constructing a stress relaxation model based on the creep displacement, and determining high-temperature viscoelastic parameters of the glass based on the stress relaxation model; Wherein, the high-temperature viscoelastic parameters of the glass include shear modulus and shear stress relaxation time.

9. A glass optical element molding die surface shape-optical error compensation device, deployed in a computing device, the device comprising: An acquisition unit, adapted to acquire the creep displacement of the glass by using a creep test method based on constant pressure stress micro-deformation low friction disturbance axial compression, and determine the high temperature viscoelastic parameters of the glass based on the creep displacement; A construction unit, adapted to construct an initial glass optical element profile curve equation, and determine initial molding die parameters based on the initial glass optical element profile curve equation; An establishing unit adapted to establish a simulation model of a glass preform under force-heat coupling based on the initial molding die parameters; A simulation prediction unit, adapted to use a simulation prediction model to simulate the compression molding process based on the initial compression mold parameters, the glass preform simulation model and the glass high-temperature viscoelastic parameters to obtain a simulated glass optical element, and predict the surface error and optical error of the simulated glass optical element to obtain a corresponding predicted surface error and predicted optical error; The compensation unit is adapted to compensate the initial molding die parameters based on the predicted surface shape error and the predicted optical error to obtain compensated molding die parameters, so as to manufacture the compensated molding die based on the compensated molding die parameters.

10. A computing device comprising: at least one processor; and A memory storing program instructions, wherein the program instructions are configured to be processed by the at least one processor, and the program instructions include instructions for processing the method according to any one of claims 1 to 8.

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