JP3852121B2 - Optical element mold design method and optical element mold design support system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mold design means for manufacturing an optical element that does not require grinding and polishing after molding.
[0002]
[Prior art]
Conventionally, in order to manufacture optical elements having various shapes, in particular, optical elements having an aspherical shape, an optical glass material is heated, softened, molded, and then cooled. It was broken. Further, in such a molding process, the shape of the mold is transferred to the glass surface of the optical glass material with high accuracy, so the design of the mold has been made to match the design shape of the optical element. .
[0003]
[Problems to be solved by the invention]
However, in general, the shape of the mold does not match the surface shape of the molded optical element. It is generally known that this reason is caused by thermal deformation of a mold material or glass material, and further generation of thermal stress caused by temperature distribution inside the molded optical element. In particular, the `` stress '' that occurs inside the glass material during molding and remains after cooling causes distortion of the surface shape of the optical element after molding, so-called `` sink '', and the shape of the optical element is the design target. It is the main factor that will not match the shape to be.
[0004]
Temporarily, if the state of the glass material at the time of molding, such as temperature, stress, etc. can be measured, the amount of change from the design target value of the shape of the optical element to be manufactured, from this prediction, It is possible to manufacture a mold that has been corrected in consideration of the amount of deformation. However, in general, since it is impossible to measure the temperature, stress, and the like inside the glass material, the prediction as described above has to rely on thermal deformation simulation by a finite element method or the like.
[0005]
By the way, when performing such thermal deformation simulation, the most important thing is to create an accurate simulation model. However, glass materials have various characteristics such as thermal expansion coefficient that are nonlinear and have a temperature function. Therefore, it is extremely difficult to create an accurate model, and it is impossible to predict the amount of change from the design target value of the shape of the optical element to be manufactured simply by performing thermal deformation simulation. .
[0006]
For these reasons, in order for the shape of the optical element to have a desired design value, a change in shape is predicted from the surface shape data of the optical element obtained by molding without using simulation, The design method that has been carried out has been to optimize the shape of the mold while correcting the mold. In other words, in order to perform the prediction, it is necessary to perform the molding work at least once, and when the prediction result deviates from the allowable range at the time of design, the mold is corrected and processed several times. It was necessary to carry out, and the work which required very many man-hours, cost, time etc. was performed.
[0007]
Then, an object of this invention is to provide the means to manufacture a highly accurate shaping | molding die with few man-hours.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, there are the following means.
[0009]
That is, a method for designing a mold for molding an optical element having a desired shape using an optical glass material, and firstly, a thermal expansion coefficient identification process for determining a thermal expansion coefficient of the optical glass material is performed. Next, there is an optical element molding die design method for performing molding die simulation processing for obtaining a molding die at room temperature by thermal deformation simulation using the obtained thermal expansion coefficient.
[0010]
Furthermore, the thermal expansion coefficient identification process is roughly divided into two systems, and the first system manufactures an optical element by molding an optical glass material using a mold that has already been manufactured. A process, an annealing process for heating and cooling the optical element in a predetermined temperature pattern, and a measurement process for measuring the shape of the optical element after the annealing process. The second system includes a step of measuring the shape of the mold, a mold deformation calculating step of obtaining a mold shape of the mold in a predetermined temperature state by a thermal deformation simulation, and the optical glass material. Temporarily giving a thermal expansion coefficient, and using the mold shape obtained in the mold deformation calculation step and the temporarily input thermal expansion coefficient, the shape of the optical glass material at room temperature is obtained by a thermal deformation simulation. And determining a coefficient of thermal expansion in which the difference between the measurement result of the measurement process of the first system and the thermal deformation simulation by the material shape calculation process of the second system is within a predetermined range. This is an optical element molding die design method.
[0011]
Further, the molding die simulation process specifically uses the shape of the optical glass material designed in advance to a desired shape and the thermal expansion coefficient determined in the thermal expansion coefficient identification process, so that the optical mold in a predetermined temperature state is used. A material deformation calculation step for obtaining the shape of the glass material by thermal deformation simulation, and a mold design step for obtaining the shape of the mold at room temperature by the thermal deformation simulation from the shape of the optical glass material obtained by the step, This is an optical element mold designing method.
[0012]
The predetermined temperature state is preferably a temperature state where the optical glass material is at a transition point.
[0013]
The following system aspects are also conceivable.
[0014]
That is, a design support system for a mold for optical elements, an input means for inputting at least a given thermal expansion coefficient, a processing means for performing a design support process for a mold, and a display for displaying a processing result Means.
[0015]
The processing means includes a material deformation calculation process for obtaining a shape of the optical glass material in a predetermined temperature state by a thermal deformation simulation using a preliminarily designed shape of the optical glass material and a given thermal expansion coefficient, and The system performs a mold design process in which the shape of the mold at room temperature is determined by thermal deformation simulation from the shape of the optical glass material determined by the process.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
First, an outline of the present invention will be described, and then specific embodiments will be described with reference to the drawings.
[0017]
As a result of intensive research to obtain a mold that the molding surface of the optical element can accurately correspond to the desired design value, an annealing treatment is first added as a process after molding the optical glass material. Furthermore, only two states, room temperature and molding temperature, are considered as the molding state, and the thermal expansion coefficient is a virtual physical quantity that takes a fixed value regardless of the temperature.
[0018]
Under such conditions, for example, by molding an optical glass material with a mold designed by thermal deformation simulation using the finite element method, the shape of the molding surface of the optical element can be easily reduced to the design value. We found that it was within the allowable range. This will be described in detail as follows.
[0019]
In general, when molding conditions such as temperature, molding pressure, molding time and the like are optimized, a molded product is obtained by repeatedly performing molding under such conditions. For the same glass type, if the shape of the optical element to be molded is different, the conditions such as molding pressure and molding time will be somewhat different, but the viscosity value of the glass that gives good molding results is within a limited range. Therefore, the molding temperature is the same even if the shape of the optical element is different.
[0020]
Further, in order to obtain a good shape as designed on the entire surface of the molded optical element surface, it is expected that the entire molded surface is within a certain temperature range. Furthermore, since the plastic deformation may occur when the molding pressure is depressurized above the glass transition point (Tg point), the depressurization is performed to the Tg point that is the elastic deformation region or less. In general it is not.
[0021]
Furthermore, for the purpose of removing the internal stress generated when the high-temperature glass is rapidly cooled, i.e., the permanent distortion and the non-uniform refractive index distribution generated by the distortion, the optical glass material has an annealing point. An annealing treatment is performed, which is a process of slowly cooling to the strain point (the temperature at which the viscous flow of the glass material starts and the strain can be removed) that is heated and maintained near (the temperature at which the internal strain can be removed). To do.
[0022]
The optical glass material immediately after depressurization has a temperature distribution inside, and when it is rapidly cooled to room temperature, it is expected that distortion will occur along with the generation of thermal stress inside the material. When the annealing process is added to the subsequent process, the annealing process removes the internal distortion of the glass material, so that it is not necessary to consider the influence of the distortion on the final shape. That is, from these, it can be considered that the shape of the molding die at the decompression temperature near the Tg point is directly transferred to the glass material under the optimum molding conditions including the annealing step.
[0023]
Originally, the molding includes various nonlinear elements, but by providing the above-mentioned assumption, it is sufficient to consider only two states, a state at a decompression temperature near the Tg point and a state at room temperature. The state can be assumed to be a steady state.
[0024]
In addition, the thermal expansion coefficient is non-linear and is a physical quantity having temperature characteristics. However, as described above, since molding is repeated under the same conditions, the history of changes in the thermal expansion coefficient during molding must be equal. Therefore, it is assumed that the coefficient of thermal expansion takes a fixed value regardless of the temperature. However, in order to obtain such a virtual thermal expansion coefficient, it is necessary to identify the thermal expansion coefficient by determining the thermal expansion coefficient from the actual mold shape data and the shape data of the molded glass surface. It becomes. However, since the thermal expansion coefficient obtained for a certain glass type can be applied to other molded shapes as long as the glass material is of the same type, the identification of the thermal expansion coefficient need only be performed once per glass type.
[0025]
Then, after the thermal expansion coefficient identification work, the mold at room temperature is obtained by thermal deformation simulation using the obtained thermal expansion coefficient.
[0026]
As described above, according to the present invention, a molding operation for predicting a change in the molding shape and a correction operation for the mold shape are not required, and the delivery time of the optical element product can be greatly shortened. In addition, by introducing the thermal expansion coefficient as described above, calculations such as simulation are simplified and can be performed in a short time, so it is possible to handle a wide variety of molding shapes and glass types without time constraints. Can do.
[0027]
Hereinafter, embodiments according to the present invention will be described with reference to the drawings.
[0028]
First, a configuration example of a system to which the present invention is applied will be described, and then a molding die design method will be described.
[0029]
FIG. 7 shows a system configuration according to the present invention. This system functions as a support system that supports high-precision mold design.
[0030]
The system includes an input device 16 for inputting a command for giving a predetermined instruction and a physical quantity such as a thermal expansion coefficient, a display device 12 for displaying a simulation result and a shape measurement result, and various calculations and display processing. An arithmetic / processing device 14 to perform, and a shape measuring machine 18 for measuring a shape exhibited by a given mold or molded glass material are configured.
[0031]
Data measured by the shape measuring machine 18 is input to the arithmetic / processing device 14 via a communication cable. Note that when the measurement mode is designated by the input device 16, the measurement data may be input to the arithmetic / processing device 14 from the shape measuring machine 18. The shape measuring machine 18 is configured to include a probe for measuring in contact with a measurement target, and a signal processing unit for processing a detection signal of the probe and outputting it as shape data. A contact-type measuring device may be used.
[0032]
Hereinafter, the shape measuring machine 18 using this contact-type measuring device is assumed.
[0033]
Further, the arithmetic / processing device 14 receives and interprets an input instruction, and performs processing according to the input instruction, for example, display processing for displaying the result calculated by itself on the display device 12. .
[0034]
Further, the calculation / processing device 14 has a function of performing a calculation for identifying a thermal expansion coefficient, a thermal deformation simulation between the room temperature and the transition point of the molding die and the glass material shape after molding, and the like. .
[0035]
As such thermal deformation simulation, what is used comparatively well in a known method, for example, an object is divided into a plurality of elements, and simultaneous equations relating to nodes of each element are solved to obtain the amount of thermal deformation. A finite element method simulation may be employed. Parameters such as the shape of the object, the coefficient of thermal expansion of the object, the temperature at which the simulation is performed, and the like necessary for the thermal deformation simulation are given to the arithmetic / processing device 14 via the input device 16.
[0036]
The arithmetic / processing device 14 can be realized by an electronic device such as a ROM in which a program is preliminarily stored, a CPU that performs predetermined arithmetic and processing in accordance with a program stored in the ROM, and a memory that functions as a work area.
[0037]
The design method of the present invention, including thermal deformation simulation, may be configured in advance in a ROM or the like in the form of a program.
[0038]
In addition, a program for realizing the method according to the present invention is started in accordance with a command given via the input device.
[0039]
The input device 16 can be realized by a keyboard, a mouse, or the like, and the display device 12 can be realized by a CRT, a liquid crystal display, an EL display, or the like. Although not shown, a configuration including a printing device or the like for outputting a calculation result may be used.
[0040]
Next, in order to facilitate understanding of the present invention, an outline of a glass material molding process using a mold will be described.
[0041]
FIG. 1 is a view showing a state in which a glass blank is set in a mold (at room temperature) in order to form a glass blank.
[0042]
Reference numeral 1 denotes a glass blank which is a glass material to be molded, and reference numerals 2 and 3 denote a molding upper mold and a molding lower mold, respectively. 4 is a sleeve, 5 is a platform, and 6 is a push rod.
[0043]
A sleeve 4 is installed on the platform 5. In the sleeve 4, the lower molding die 3 and the upper molding die 2 are provided so as to face each other, and a glass blank is formed between the molding upper die 2 and the lower molding die 3 in order to mold the glass blank 1. The glass blank 1 can be set in a state where 1 is held.
[0044]
The movement of the molding upper mold 2 is regulated by the sleeve 4 installed on the mounting table 5, and the molding upper mold 2 is configured to be movable in the vertical direction.
[0045]
At the time of actual molding, the push rod 6 is pushed by driving a machine (not shown), the upper mold 2 moves downward, presses the glass blank 1, and performs a molding operation.
[0046]
As the glass blank 1, for example, a phosphoric acid optical glass is used, and the shape of the glass blank 1 may be spherical as shown in FIG. Further, the molding upper mold 2 and the molding lower mold 3 in the sleeve 4 are, for example, WC alloy molds. And the glass blink 1 which made the fluorophosphoric optical glass spherical is set in a state of being sandwiched between a molding upper mold 2 and a molding lower mold 3 made of WC alloy.
[0047]
The above is the outline of the configuration of the molding machine configured with the molding die and the set state of the glass blank, which is the glass material to be molded, at room temperature.
[0048]
An example of actual molding conditions is shown in FIG.
[0049]
In FIG. 2, the horizontal axis represents “time (unit: minute)” and the vertical axis represents “temperature (unit: ° C.)”.
[0050]
As can be seen with reference to FIG. 2, the molding machine shown in FIG. 1 is heated to 480 ° C. after 10 minutes in an inert gas atmosphere. The mold, glass blink, etc. are at a temperature of 480 ° C., and at a point where heat balance is achieved (time, 20 minutes), a pressure load of 100 (kgf / cm ² ) For 5 minutes (time 20-25 minutes). That is, the push rod 6 is driven to move the molding upper die 2 downward. Thereafter, the pressure is reduced at the point where the temperature is lowered to 430 ° C. (time 29 minutes), and further, the temperature is rapidly lowered to room temperature, so-called rapid cooling is performed.
[0051]
Then, the annealed optical element is annealed. By performing this annealing treatment, the internal distortion of the optical element is removed, the refractive index distribution is not biased, and a uniform refractive index distribution is exhibited.
[0052]
FIG. 8 shows an example of annealing conditions.
[0053]
The horizontal axis indicates “hour” and the vertical axis indicates “temperature (° C.)”, and shows a temperature pattern that changes in accordance with the passage of time.
[0054]
As shown in the figure, the temperature is increased to 400 (° C.) in 5 hours, the temperature is kept constant for 29 hours, and the temperature is further increased from 400 (° C.) to 350 (° C.) by 79 hours. Cool slowly until Thereafter, the temperature is lowered to room temperature.
[0055]
An annealing process is performed to remove the internal distortion of the optical element by heating and cooling the optical element with such a temperature pattern.
[0056]
Now, there are three types of optical element design shapes used for the description in this embodiment, and the respective shapes are shown in FIG. 3, FIG. 4, and FIG.
[0057]
The design shape shown in FIG. 3 is a spherical lens with one radius of curvature 9 (mm) (R9), the other radius of curvature 11 (mm) (R11), thickness 6 (mm), and aperture 13 (mm). The design shape shown in FIG. 4 is a spherical lens with a radius of curvature of 20 (mm) (R20) on one side, a radius of curvature of 7 (mm) (R7), a thickness of 5 (mm), and a diameter of 12 (mm). In addition, the design shape shown in FIG. 5 is one radius of curvature 7 (mm) (R7), the other radius of curvature 25 (mm) (R25), thickness 4 (mm), aperture 11 (mm) It is a spherical lens. Although not described in the present embodiment, an aspherical lens may be a design target. Rather, it is generally difficult to design a mold, and the effect of applying the present invention to the aspherical lens mold design is greater. .
[0058]
Note that, as shown in FIGS. 3 to 5, the explanation will be given by taking three types of design shapes as an example in order to show that the present invention can be applied to the design of a mold for optical elements having various shapes. is there.
[0059]
Now, the outline of the processing in the present invention will be described with reference to FIG.
[0060]
This processing is executed by the arithmetic / processing device 14 included in the system by performing an operation for giving a specific command to the above-described system via the input device 16.
[0061]
The identification process of the virtual thermal expansion coefficient used in the present invention was performed on the optical element shown in FIG. The identification process of the thermal expansion coefficient is performed according to the following processing procedure. Hereinafter, these processing procedures will be described with reference to the drawings.
[0062]
In FIG. 7, step 10, it is first determined whether or not a simulation for identifying a thermal expansion coefficient has been performed previously for the glass type. If a simulation for identifying the thermal expansion coefficient has been performed for the glass type before, the data is used as the thermal expansion coefficient for the glass type.
[0063]
(1) In step 20, the respective shapes of the upper mold and the lower mold are measured using a contact-type measuring instrument. Such data is sent to and stored in the arithmetic / processing device.
[0064]
(2) The obtained shape measurement data is in the initial state at room temperature, the thermal expansion coefficient of the WC alloy, the temperature of the Tg point (transition point) is given as a parameter, and the thermal deformation simulation using the finite element method, The shape of the mold at the Tg point is obtained for each of the upper mold and the lower mold (step 30).
[0065]
The concept of this simulation will be described with reference to FIG.
[0066]
In FIG. 9, the glass to be molded and the upper mold among the molds are shown. A solid line and a dotted line indicate the shapes at room temperature and when the temperature is raised (for example, a transition point), respectively.
[0067]
Step 30 is a process of obtaining, by thermal deformation simulation, the shape “c” when the temperature of the mold shape “d” at room temperature rises to the transition point (Tg point).
[0068]
(3) It is assumed that the obtained mold shape is transferred to glass (blank). Then, the shape of the mold is set as an initial state, a virtual thermal expansion coefficient of glass is temporarily input, and the shape of the optical element at room temperature is obtained by thermal deformation simulation using a finite element method.
[0069]
That is, the glass thermal expansion coefficient is temporarily input (step 40), and the glass shape at room temperature is obtained by simulation from the simulation result of the mold at the Tg point and the temporarily input glass thermal expansion coefficient (step 50). ).
[0070]
The concept of this simulation will be described with reference to FIG.
[0071]
If the shape “c” of the mold at the Tg point is transferred to the glass surface with high accuracy, the glass is molded to have the shape shown in FIG. 9 “b”. Then, the shape “a” when the glass having the shape shown in “b” reaches room temperature is obtained by simulation. The shape “a” is for the coefficient of thermal expansion of the temporarily input glass.
[0072]
(4) On the other hand, molding is performed under optimum conditions, and after annealing the molded optical element, its shape is measured using a contact-type measuring instrument. The measurement is performed on both sides of the optical element.
[0073]
That is, an optical element is manufactured by molding a glass material using a mold (step 90), the above-described annealing treatment is performed on the optical element (step 100), and the glass shape after molding, that is, Then, the shape of the optical element is measured (step 110).
[0074]
(5) Comparing the shape data of the optical element obtained by the measurement and the shape data obtained by simulation, until the difference between the two data becomes a value within the design allowable range of the optical element, virtual thermal expansion is performed. Coefficient identification processing is performed.
[0075]
That is, the optical element shape measurement data obtained in step 110 is compared with the optical element shape simulation data obtained in step 50 to determine whether or not the difference between the two data falls within a predetermined range. To do.
[0076]
If the difference between the two data is within the predetermined range, the thermal expansion coefficient provisionally input in step 40 is determined as the thermal expansion coefficient for the glass type. Conversely, if the difference between the two data is not within the predetermined range. The processing from step 40 is repeated, and the thermal expansion coefficient for the glass type is determined so that the difference between the two data falls within a predetermined range.
[0077]
The inventor employed an interferometer whose light source is g-line, and observed Newton rings in which bright and dark stripes are arranged in a concentric circle. That is, as a result of comparing the shape difference between the shape of the optical element obtained by the simulation using the virtual thermal expansion coefficient and the shape of the actually formed optical element using an interferometer, It was confirmed that the lower surface was within one stripe by Newton ring.
[0078]
As a result, it can be seen that the shape obtained by simulation using the virtually calculated coefficient of thermal expansion is within the allowable design range that can withstand practical use.
[0079]
Furthermore, as a result of performing the processing described above on the optical element having the shape shown in FIG. 4, the virtual thermal expansion coefficient obtained is a virtual one for the optical element having the shape shown in FIG. It was found that the value was within “± 1 (%)” of the thermal expansion coefficient.
[0080]
Therefore, it has also been confirmed that the virtual thermal expansion coefficient described above can be applied to any glass material of the same type.
[0081]
Next, using the virtual thermal expansion coefficient obtained for the optical element having the shape shown in FIG. 3, the shape of the mold is obtained such that the shape of the optical element having a desired design value is obtained. It calculated | required with the following process procedures. Here, the obtained shape of the mold is different from the shape to be identified in the identification process described above, that is, for the optical element having the shape shown in FIG.
[0082]
Hereinafter, simulation of the mold will be described.
[0083]
The following processing is also executed by the arithmetic / processing device by inputting a predetermined command via the input device.
[0084]
(1) First, a glass shape at the Tg point is obtained from a glass shape at the time of design and a virtual thermal expansion coefficient by a thermal deformation simulation using a finite element method (step 70). That is, the shape of the upper and lower surfaces of the optical element at the Tg point is obtained.
[0085]
The concept of this simulation will be described with reference to FIG.
[0086]
This is a process of obtaining “b”, which is the glass shape at the Tg point, by simulation, assuming that the design shape of the glass at room temperature is “a”.
[0087]
(2) From the glass shape at the Tg point, the shape of the mold at room temperature is obtained by simulation (step 80).
[0088]
That is, it is assumed that the glass shape obtained in step 70 has the shape of the molding die transferred with high accuracy, and the shape of the molding die at room temperature is converted into the upper die and the lower die by thermal deformation simulation using the finite element method. Ask about each of the.
[0089]
The concept of this simulation will be described with reference to FIG.
[0090]
It is assumed that the shape of the glass at the Tg point is “b” and the shape “c” of the mold at the Tg point is transferred. Then, if the shape “d” of the mold at the Tg point is obtained at room temperature, this shape “d” is the shape of the mold to be obtained.
[0091]
The inventor performed molding of a glass blank using the mold obtained by such a simulation, and performed verification work of the simulation using the above-described interferometer. And as a result of comparing the shape of the molded optical element and the design value, it was confirmed that the difference between the upper and lower surfaces of the optical element was within one stripe by Newton's ring and was within the design allowable range. did.
[0092]
Through the above processing, the mold can be designed easily, quickly and with high accuracy by simulation. In the description of the simulation concept of FIG. 9, only the upper mold is illustrated for the sake of easy understanding, but it is needless to say that the same description can be made for the lower mold.
[0093]
【The invention's effect】
As described above, according to the present invention, it is possible to design a mold for molding a glass material into an optical element having a desired shape with high accuracy and with a small number of man-hours and a low cost. As a result, the cost of the optical element can be reduced and the delivery period can be greatly reduced.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a set state at room temperature for forming a glass material.
FIG. 2 is an explanatory diagram of an example of molding conditions.
FIG. 3 is an explanatory diagram of a shape example of an optical element.
FIG. 4 is an explanatory diagram of a shape example of an optical element.
FIG. 5 is an explanatory diagram of a shape example of an optical element.
FIG. 6 is a flowchart showing the processing contents according to the present invention.
FIG. 7 is a configuration diagram of a system according to the present invention.
FIG. 8 is an explanatory diagram of an example of conditions for annealing.
FIG. 9 is an explanatory diagram of a simulation for mold design.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Glass blank, 2 ... Molding upper mold, 3 ... Molding lower mold, 4 ... Sleeve, 5 ... Mounting stand, 6 ... Pushing rod

Claims (8)

A method of designing a mold for molding an optical element having a desired shape using an optical glass material,
First, a thermal expansion coefficient identification process is performed to determine a virtual thermal expansion coefficient assuming that the thermal expansion coefficient of the optical glass material takes a fixed value regardless of temperature ,
Next, an optical element molding die design method for performing molding die simulation processing for obtaining a molding die at room temperature by thermal deformation simulation using the obtained virtual thermal expansion coefficient. In Claim 1, the said thermal expansion coefficient identification process is divided roughly into two systems,
The first system is
A step of producing an optical element by molding an optical glass material using a mold that has already been produced;
An annealing step for heating and cooling the optical element in a predetermined temperature pattern;
Measuring step of measuring the shape of the optical element after the annealing step,
The second system is
Measuring the shape of the mold;
A mold deformation calculation step of obtaining a mold shape of the mold in a predetermined temperature state by thermal deformation simulation; and
Temporarily giving the thermal expansion coefficient of the optical glass material, and using the mold shape obtained in the mold deformation calculation step and the temporarily input thermal expansion coefficient, the shape of the optical glass material at room temperature is obtained by thermal deformation simulation. A desired material shape calculation step,
Furthermore, the step of determining the virtual thermal expansion coefficient, the difference between the measurement result of the measurement process of the first system and the thermal deformation simulation by the material shape calculation process of the second system is within a predetermined range, Optical element mold design method. The mold simulation process according to claim 1,
The shape of the optical glass material in a predetermined temperature state is obtained by thermal deformation simulation using the shape of the optical glass material designed in advance in a desired shape and the virtual thermal expansion coefficient determined in the thermal expansion coefficient identification process. A material deformation calculation process;
A method for designing an optical element mold, comprising: a mold design step for obtaining a shape of a mold at room temperature from a shape of an optical glass material obtained by the step by a thermal deformation simulation.   4. The optical element mold design method according to claim 2, wherein the predetermined temperature state is a temperature state in which the optical glass material is at a transition point.   5. The optical element mold design method according to claim 1, wherein the shape of the optical glass material is a spherical surface or an aspherical surface.   5. The thermal deformation simulation according to claim 1, wherein the thermal deformation simulation is performed by dividing a simulation target into a plurality of elements, formulating each divided element, and obtaining a solution of each formula. An optical element mold designing method, which is a finite element method simulation for obtaining thermal deformation of a simulation target. An optical element mold support system,
Input means for inputting at least a virtual thermal expansion coefficient that is assumed to have a given thermal expansion coefficient and takes a fixed value regardless of temperature, processing means for performing design support processing of the mold, and processing Display means for displaying the results,
The processing means includes
A material deformation calculation process for obtaining a shape of the optical glass material in a predetermined temperature state by a thermal deformation simulation using the shape of the optical glass material provisionally designed in advance and the given virtual thermal expansion coefficient, and An optical element mold design support system for performing a mold design process for obtaining a shape of a mold at room temperature from a shape of an optical glass material obtained by processing by a thermal deformation simulation. The optical glass material and the mold according to claim 7, further comprising a measuring device for measuring the shape of the optical glass material and the mold,
In order to determine a virtual coefficient of thermal expansion of a given optical glass material, the processing means
A mold deformation calculation process for measuring a shape of a given mold using the measuring machine, and using the measurement result, a mold shape of the mold in a predetermined temperature state is obtained by a thermal deformation simulation; Temporarily input the thermal expansion coefficient of the optical glass material, and using the mold shape obtained by the mold deformation calculation process and the temporarily input thermal expansion coefficient, the shape of the optical glass material at room temperature is subjected to thermal deformation simulation. The material shape calculation process obtained by
An optical element produced by molding an optical glass material using a mold, after the annealing process is performed, when the optical element is given, a measurement process for measuring the shape by the measuring instrument,
An optical element mold design system for performing a process for determining the virtual thermal expansion coefficient, wherein a difference between a measurement result by the measurement process and a thermal deformation simulation by the material shape calculation process is within a predetermined range.

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