JP2007119307A - Method for simulating forming of optical element and method for designing mold for optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently estimate the occurrence of burrs in an optical element material by simulating the forming process when an optical element is formed. <P>SOLUTION: An analysis model in which a glass workpiece 7 is interposed between a couple of mold assemblies vertically arranged opposite to each other is set, and a nearly central part of the joining part 33 between adjacent mold 21 and mold die 22 is defined as a target coordinate (point c), and the distance from the target coordinate to end faces (point a, point b) is set as a judgment area. Further, in the judgment area, the contact pressure between a virtual shape including outer shapes of the mold 21 and the mold die 22 at the joining part 33 and a shape extending to the target coordinate from each end parts, and the contour part of the glass workpiece 7 at the finally pressed position is simulated. The simulated contact pressure is compared with the preset predetermined contact pressure. When the simulated contact pressure is higher than the predetermined contact pressure, it is estimated that a burr may occur in the glass workpiece 7. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a molding simulation method when a mold shape is transferred to an optical element material for molding in manufacturing a high-precision optical element such as an aspheric lens, a prism, or a mirror, and a molding die design method for the optical element. .

  In recent years, in order to reduce the size and weight of optical devices, many glass optical elements having complicated surface shapes such as aspherical lenses and prisms having a lens function have been adopted. Optical elements having such complicated surface shapes are not easily manufactured by grinding or polishing, and a manufacturing method in which a heat-softened glass material is press-molded by a mold assembly is employed.

  On the other hand, optical elements mounted on optical equipment are required to have high-precision shapes, but in order to manufacture high-precision optical elements by press molding, many trials have been made on molding conditions and mold assembly shapes. And it is necessary to set to the optimum state. However, it takes a lot of time and money to actually perform the molding by adjusting the molding conditions using the mold assembly and to prototype and evaluate the molded product.

  Also, when molding a glass lens or a synthetic resin lens using a mold assembly in which a plurality of mold members are combined, the glass or the synthetic resin enters the joint portion of the combined mold members and no burrs are generated. It is necessary to design the mold member shape in consideration of the above.

  Therefore, in recent years, a simulation technique related to a molding process at the time of molding an optical element has attracted attention, and a method for performing simulation related to a molding process and setting an optimal molding condition and an optimal mold member shape is disclosed.

  Regarding the molding condition setting method, for example, Patent Document 1 discloses that when an optical element material is heated and pressed in a cavity formed by a pair of upper and lower dies arranged coaxially, as an optical element material, It is disclosed that a chamfered portion having a volume equal to or larger than the volume change amount of the optical element material when the thickness is changed by 0.1 mm is provided on the outer peripheral portion of the effective optical surface.

As a result, it is possible to prevent the press-molded optical element from being filled in the cavity, biting into the corner of the mold, cracking the optical element, or preventing the material from adhering to the mold. Is.
JP-A-5-301723 (page 3, FIG. 2)

  However, in the above-mentioned Patent Document 1, an attempt is made to solve the problem of burrs by providing a chamfered portion in the optical element material in consideration of variations in the optical element material before molding. It is necessary to determine the degree of filling of the optical element material into the cavity. For this reason, in some cases, it is necessary to redesign the mold, which requires a lot of time due to trial and error.

  Further, in Patent Document 1, an attempt is made to avoid the generation of burrs by changing the shape of the optical element material. However, there is a case where the degree of freedom in changing the shape of the optical element material is not given from the viewpoint of increasing the cost of material processing. is there.

  The present invention has been made to solve such problems, and an object of the present invention is to provide an optical element molding simulation method capable of efficiently predicting the occurrence of burrs in the optical element material. It is in.

In order to achieve the object, the invention according to claim 1
In the optical element molding simulation method for simulating the molding process when molding the optical element by pressing the heat-softened optical element material,
Setting a simulation model having a pair of mold assemblies including a pair of molds arranged in opposition and an optical element material interposed between the pair of molds;
Of the mold members constituting the pair of mold assemblies, the approximate center of the joint portion between the molding die and the adjacent mold member is used as the coordinate of interest, and the distance from the coordinate of interest to the end of the joint portion, or Set the distance from the target coordinates to any position as the judgment area,
Within the determination region, an outer shape of each mold member at the joint, a virtual shape including a shape extending from the end to the target coordinate, and a contour of the optical element material at the final pressing position, Simulate contact pressure,
Comparing the simulated contact pressure with a predetermined contact pressure set in advance;
When the contact pressure is larger than the predetermined contact pressure, it is predicted that burrs will occur in the optical element material.

The invention according to claim 2 is the optical element molding simulation method according to claim 1,
The predetermined contact pressure is set to zero.

The invention according to the method for designing a mold for an optical element according to claim 3 is:
Using the molding simulation method for an optical element according to claim 1 or 2,
When it is predicted that burrs will occur, the joining distance of the joint is changed.

The invention relating to the mold designing method for an optical element according to claim 4 comprises:
Using the molding simulation method for an optical element according to claim 1 or 2,
When it is predicted that burrs will occur, the joining position of the joint is changed.

The invention according to claim 5
In the optical element molding simulation method for simulating the molding process when molding the optical element by pressing the heat-softened optical element material,
Setting a simulation model having a pair of mold assemblies including a pair of molds arranged in opposition and an optical element material interposed between the pair of molds;
Of the mold members constituting the pair of mold assemblies, the approximate center of the joint portion between the molding die and the adjacent mold member is used as the coordinate of interest, and the distance from the coordinate of interest to the end of the joint portion, or Set the distance from the target coordinates to any position as the judgment area,
Within the determination area, the outer shape of each mold member at the joint, the position coordinates of the virtual shape including the shape extending from the end to the target coordinate, and the contour of the optical element material at the final pressing position And the position coordinates of
When the position coordinates of the virtual shape in the simulated joint portion are compared with the position coordinates of the contour portion of the optical element material at the final pressing position, and include portions where the respective position coordinates match, It is predicted that burrs will occur in the element material.

The invention according to the method for designing a mold of an optical element according to claim 6 is:
Using the molding simulation method for an optical element according to claim 5,
When it is predicted that burrs will occur, the joining distance of the joint is changed.

The invention relating to the mold designing method for an optical element according to claim 7 comprises:
Using the molding simulation method for an optical element according to claim 5,
When it is predicted that burrs will occur, the joining position of the joint is changed.

  According to the present invention, it is possible to efficiently predict the occurrence of burrs in the optical element material by simulation. Moreover, based on this prediction, an optimal mold can be designed, and a trial experiment can be omitted.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Configuration of molding machine)
FIG. 1 shows the overall configuration of the molding machine 100, and FIGS. 2 (a) and 2 (b) are enlarged views of the main part thereof. In FIG. 1, a molding machine 100 has a pair of upper and lower mold assemblies 10 and 20 arranged opposite to each other, and the mold assemblies 10 and 20 have molding surfaces 11a and 21a (see FIG. 2A), respectively. And mold dies 12 and 22 for supporting the molds 11 and 21 from the periphery, and die plates 13 and 23 for supporting the end surfaces of the molds 11 and 21 and the mold dies 12 and 22. Each has a mold member. The glass material 7 as the optical element material is placed on the molding surface 21 a of the molding die 21.

  The mold assemblies 10 and 20 may be a combination of a mold having the molding surfaces 11a and 21a and another mold member. Moreover, although the glass raw material 7 is demonstrated as an example as an optical element material, it is not restricted to this, For example, a synthetic resin raw material may be sufficient.

  Of the pair of upper and lower mold assemblies 10, 20, the upper mold assembly 10 is attached to the lower end of the fixed shaft 14 above the molding machine 100 via a heat insulating cylinder 15. The lower mold assembly 20 is attached to the upper end of the movable shaft 24 below the molding machine 100 via a heat insulating cylinder 25. A driving device (not shown) and a load detection device 26 are installed below the movable shaft 24. By moving the lower mold assembly 20 being molded up and down by the driving device, the mold is clamped while detecting the load. Pressurization and mold opening are possible.

  A transparent quartz tube 30 is attached around the mold assemblies 10 and 20, and both upper and lower ends of the transparent quartz tube 30 are in contact with the seal plates 17 and 27. The sealing plates 17 and 27 form a molding chamber 31 having airtightness around the mold assemblies 10 and 20. Further, an infrared lamp unit 32 is attached around the transparent quartz tube 30, and the mold assemblies 10 and 20 are heated together with a reflection mirror disposed at the rear of the circumference.

Further, dry nitrogen gas (N ₂ ) is introduced into the surfaces of the die plates 13 and 23 in the molding chamber 31 inside the fixed shaft 14 and the movable shaft 24 to prevent the mold assemblies 10 and 20 from being oxidized. At the same time, gas supply channels 18 and 28 for cooling are formed.
(Molding process)
A molding process when the molding machine 100 is used will be described.

  As a molding material to be used as an optical element material, a substantially spherical glass material 7 (L-BAL42 from OHARA INC.) Is used. This glass material 7 is previously placed on the molding surface 21a of the molding die 21 of the lower mold assembly 20 (see FIG. 2A). In this state, the process proceeds to the heating process. In this heating step, nitrogen gas is supplied into the molding chamber 31 from the gas supply passages 18 and 28, the interior of the molding chamber 31 is replaced with nitrogen gas, and then a pair of upper and lower molds is formed by the infrared lamp unit 32. The assemblies 10 and 20 (molding die, mold die, die plate) and the glass material 7 are heated. Here, the upper and lower molds 11 and 21 are provided with temperature sensors (not shown), and the upper and lower molds 11 and 21 are heated to about 600 ° C. Since the glass material 7 is heated while being sandwiched between the upper and lower molds 11, 21, the temperature of the glass material 7 is also heated to about 600 ° C. as with the molds 11, 21.

Subsequently, in the pressing step, first, a predetermined pressing load is applied to the mold assemblies 10 and 20, and the movable shaft 24 is driven upward as a load condition that maintains a constant pressure during cooling. Thus, as shown in FIG. 3, the glass material 7 is press-formed between the upper and lower molds 11 and 21. Further, in the cooling step after press molding, by continuously introducing nitrogen gas into the gas supply passages 18 and 28, cooling is performed from the surfaces of the die plates 13 and 23, and after cooling to near room temperature (approximately 20 ° C.), The glass material 7 (optical element) after molding is taken out between the upper and lower molds 11 and 21.
(Molding simulation method)
Next, a method for simulating the pressing step in the molding step described above will be described based on the flowchart of FIG.

In this embodiment, since the object is an axially symmetric shape, the description will be made with a two-dimensional axisymmetric model. However, when a non-axisymmetric shape is targeted, a three-dimensional model is used.
First, S1 will be described.

  In S <b> 1, among the mold members constituting the mold assemblies 10 and 20, coordinate data regarding the shapes of the molds 11 and 21 and the mold dies 12 and 22 and coordinate data regarding the material shape of the glass material 7 are read. At this time, since the molds 11 and 21 and the mold dies 12 and 22 are treated as rigid surfaces, only the coordinates of the portion expected to contact the glass material 7 are required.

  In the present embodiment, as shown in FIG. 2B, in order to simplify the simulation model, the molds 11 and 21 and the mold dies 12 and 22 are assumed to be integrated, and the contour is assumed to be a virtual line. To do. As an assumption method of the integrated imaginary line, for example, the joining portion 33 of the mold 21 and the mold die 22 extends the molding surface 21a in the outer peripheral direction to the approximate center of the joining portion 33, and the mold die surface 22a extends in the center direction. Are connected to the molding surface 21a, the line extending the molding surface 21a to the approximate center, the mold die surface 22a, and the line extending the mold die surface 22a to the approximate center. Read the virtual line shape. The approximate center coincides with the point of interest c in S10.

  In S2, the characteristic values and material property values are read into a simulation computer. Here, the characteristic value is, for example, the coefficient of friction between the glass material 7 and the upper and lower molds 11, 21, and the material property value is, for example, the longitudinal elastic coefficient, Poisson's ratio, linear expansion coefficient of the glass material 7. It is.

  In the present embodiment, in order to simplify the simulation model, the molds 11 and 21 and the mold dies 12 and 22 are treated as rigid surfaces. Therefore, the material property values of the molds 11 and 21 and the mold dies 12 and 22 are as follows. do not need. However, in a simulation model that should take into account the elastic deformation due to the pressing load of each mold member constituting the mold assemblies 10 and 20, it is necessary to use their longitudinal elastic modulus, Poisson's ratio, linear expansion coefficient, and the like.

  Moreover, in this embodiment, in order to simulate only a press process, in order to give heating temperature uniformly to the glass raw material 7, the thermal physical property value of thermal conductivity, a specific heat, and a density is not required, but in the glass raw material 7 In order to accurately predict the temperature, it is necessary to use the thermophysical values described above. Furthermore, in this embodiment, although the glass material 7 is defined as an elastic body, for example, the glass material 7 may be defined as a viscoelastic body or a plastic body, and the material physical property may be used.

Next, in S3, the molding conditions are read. The molding conditions are heating temperature, pressing load, and the like. In this embodiment, the heating temperature is approximately 600 ° C. and the pressing load is approximately 1000 N.
Next, in S4, a simulation model is created. Here, a simulation model in which the mold assemblies 10 and 20 and the glass material 7 shown in FIG. The shapes of the molds 11 and 21, the mold dies 12 and 22, and the glass material 7 are based on the data read in S1. In this embodiment, since the object is an axially symmetric shape, a two-dimensional axisymmetric analysis model is used for the purpose of shortening the calculation time. Specifically, it is created using ABAQUS / CAE (ABAQUS, Inc.).

  Although ABAQUS / CAE is used for creating the simulation model, the present invention is not limited to this, and any other software may be used as long as it can create a finite element model.

  Subsequently, in S5, the simulation is executed based on the data input to the simulation computer. Prior to this execution, the target center thickness of the glass material 7 sent from S11, the burr attention coordinate, the judgment area, and threshold evaluation information as a reference value are read. In this embodiment, the general-purpose finite element method simulation software ABAQUS / Standard (ABAQUS, Inc.) is used. However, the present invention is not limited to this, and other finite element method simulation software may be used. .

  Next, as shown in S6, the calculation is started from t = 0 seconds in the simulation software, and the behavior of the glass material 7 after Δt seconds is sequentially calculated and advanced under given molding conditions. For example, in the pressing step, the amount of deformation when the spherical glass material 7 is deformed under a uniform temperature of about 600 ° C. under a pressing load of about 1000 N is obtained each time the time advances by Δt. This is repeated until the press molding time ends, and the deformed shape of the glass material 7 at the end of the pressing step is obtained.

  Next, in S7, the center thickness of the glass material 7 after t seconds calculated numerically is calculated and output. In this embodiment, it is determined whether or not the molding is completed by checking the dimension of the center thickness.

  That is, in S8, it is determined whether or not the center thickness of the glass material 7 has reached the center thickness of the target optical element. If “No”, the process returns to S6 and the pressing process is continued. Proceed to S9. Since it is difficult to obtain a result that completely matches the target center thickness due to the characteristics of the simulation software, the setting of the target center thickness is, for example, a tolerance (for example, set value ± 0.1) ) May be provided for determination. Further, the target center wall thickness may be set not by the center wall thickness of the product (optical element) but by a timing value intended by the designer.

  In S9, a simulation result necessary to determine the occurrence of burrs is output. Specifically, for example, when the glass material 7 is deformed to the target center wall thickness, the contact pressure generated between the glass material 7 and the mold 21 and the mold die 22 and the glass material in which the pressure is generated. 7 node coordinate data is output. The other outputs the coordinates of the nodes corresponding to the outline of the glass material 7 and the coordinates of the virtual line.

For example, in FIG. 5A and FIG. 5B, when the two-dimensional coordinates are used, the center line C of the upper and lower molds 11 and 21 when the center thickness of the glass material 7 reaches the target center thickness. Based on the xy coordinates (0, 0) of the molding surface 21a on -C, all the xy coordinates of each node corresponding to the outline of the glass material 7 from this point, for example, (x ₁ , in FIG. 5B) y ₁ ), (x 2, y ₂ ),..., and all xy coordinates of each point on the virtual line assumed by the contours of the mold 21 and the mold die 22, for example, (X 1 in FIG. 5B) , Y ₁ ), (X 2, Y ₂ ),.

  In S10, based on the target center wall thickness, the burr attention coordinate, the determination area, and the threshold value sent from S11, whether or not burrs are generated in the glass material 7 during molding is determined by the following determination methods (1) to ( Determine by 6). This will be described with reference to FIGS. 6 (a) and 6 (b). In FIG. 6B, the approximate center (point c) of the joint 33 between the lower mold 21 and the mold die 22 is the coordinate of interest.

In the present embodiment, for the sake of convenience, the description will be made with the approximate center of the joint 33 between the adjacent mold 21 and the mold die 22 of the lower mold assembly 20 as the coordinate of interest. For example, the determination is made using the approximate center of the joint between the adjacent mold 11 and mold die 12 of the upper mold assembly 20 as the coordinate of interest.
[Judgment method (1)]
In this determination method, if the determination area is a point that is moved by a joining distance s of the joining portion 33 along the virtual line from the point c as the target coordinate of the burr occurrence determination, the point a , B point to c point are set as determination areas. As for the threshold value, the distance from the virtual line to the coordinates of each node corresponding to the contour portion of the glass material 7 is 0 mm. As a specific determination method, a line connecting points a to c and b serving as a determination region from the coordinates of the nodes corresponding to the contour portion of the deformed glass material 7 within the range of the x coordinates of the points a and b. The distance is calculated and compared with a threshold value of 0 mm. For example, in FIG. 6B, since the distance between the imaginary line between points a and c and the nodal point of the contour portion of the glass material 7 is 0 mm, it is determined that burrs are generated.
[Judgment method (2)]
In this determination method, the determination area is a point moved by a distance s ′ arbitrarily set by the designer along the virtual line from point c as the target coordinate for determining the occurrence of burrs, as a ′ point and b ′ point. Then, the points a ′ and b ′ to c are set as the determination region. As for the threshold value, the distance from the virtual line to the coordinates of each node corresponding to the contour portion of the glass material 7 is 0 mm. As a specific determination method, a ′ point to c point to b ′ serving as a determination region from the coordinates of the node corresponding to the contour portion of the deformed glass material 7 within the range of the x coordinate of the points a ′ and b ′. The distance to the line connecting the points is calculated, and this is compared with a threshold value of 0 mm.

Here, the reason for setting the distance for setting the determination region is that the designer needs to set a value in accordance with the design guideline.
[Judgment method (3)]
In this determination method, if the determination area is a point that is moved by a joining distance s of the joining portion 33 along the virtual line from the point c as the target coordinate of the burr occurrence determination, the point a , B point to c point are set as determination areas. The threshold value is set so that the contact pressure between the glass material 7 and the virtual line is 0 MPa. As a specific determination method, there are a value of a contact pressure with a virtual line at a coordinate of a node corresponding to a contour portion of the deformed glass material 7 within a range of an x coordinate of the points a and b, and a threshold value. Compared with 0 MPa, it is determined that burrs occur when the former contact pressure is greater than the latter threshold within the determination region.
[Judgment method (4)]
In this determination method, if the determination area is a point that is moved by a joining distance s of the joining portion 33 along the virtual line from the point c as the target coordinate of the burr occurrence determination, the point a , B point to c point are set as determination areas. The threshold value is set to a value of contact pressure between the glass material 7 and the virtual line set by the designer, for example, 30 MPa. As a specific determination method, there are a value of a contact pressure with a virtual line at a coordinate of a node corresponding to a contour portion of the deformed glass material 7 within a range of an x coordinate of the points a and b, and a threshold value. Compared to 30 MPa, it is determined that burrs occur when the former contact pressure is larger than the latter threshold value in the determination region. In this embodiment, the threshold value is set to 30 MPa. Since the threshold value decreases as the distance increases and the heating temperature increases, the threshold value is changed depending on the relationship.
[Judgment method (5)]
In this determination method, the determination area is a point moved by a distance s ′ arbitrarily set by the designer along the virtual line from point c as the target coordinate for determining the occurrence of burrs, as a ′ point and b ′ point. Then, the points a ′ and b ′ to c are set as the determination region. The threshold value is set so that the contact pressure between the glass material 7 and the virtual line is 0 MPa. As a specific determination method, the value of the contact pressure with the virtual line at the coordinates of the node corresponding to the contour portion of the deformed glass material 7 within the range of the x coordinate of the points a ′ and b ′, the threshold value Compared with 0 MPa, the burr is determined to occur when the former contact pressure is greater than the latter threshold within the determination region.
[Judgment method (6)]
In this determination method, the determination area is a point moved by a distance s ′ arbitrarily set by the designer along the virtual line from point c as the target coordinate for determining the occurrence of burrs, as a ′ point and b ′ point. Then, the points a ′ and b ′ to c are set as the determination region. The threshold value is set to a value of contact pressure between the glass material 7 and the virtual line set by the designer, for example, 30 MPa. As a specific determination method, the value of the contact pressure with the virtual line at the coordinates of the node corresponding to the contour portion of the deformed glass material 7 within the range of the x coordinate of the points a ′ and b ′, the threshold value When the contact pressure of the former is larger than the latter threshold in the determination region, it is determined that burrs are generated.

  And when it determines with a burr | flash generate | occur | producing in S10 (Yes), it progresses to S12 and moves the position of the junction part 33 of a type | mold member to an outer peripheral direction from a shaping | molding die center. Thereby, since the determination area | region moves to the junction part 34 (refer FIG. 7) of an outer peripheral direction, it can set to the position which the deformed glass raw material 7 does not contact, and can improve in the direction which prevents generation | occurrence | production of a burr | flash.

  Alternatively, the joining accuracy (joining distance) of the joining portion 33 of the mold member is changed. Thereby, although the deformation | transformation shape of the glass raw material 7 does not change, since the determination area | region becomes small and the value of the contact pressure which is a determination threshold value becomes large, it can improve in the direction which prevents generation | occurrence | production of a burr | flash. The designer makes such a change and returns to S1.

  That is, in this embodiment, when it is determined that burrs are generated, the shape of the glass material 7 is not changed, but the adjacent mold member, specifically, the mold, and the bonding position of the mold die are centered on the mold. Change the design so that it moves in the outer circumferential direction. If it is determined that no burr occurs (No), the simulation is terminated.

  When it is determined that burrs are generated as described above, the designer determines the position of the joint 33 between the mold 21 and the mold die 22 in the mold assemblies 10 and 20 as shown in FIG. Generation of burrs can be avoided by moving to the right joining portion 34 in the figure by t. Alternatively, the designer can avoid the occurrence of burrs by improving the joining accuracy (joining distance) of the joining portion 33, that is, by reducing the gap amount or changing the joining pressure.

It is a figure which shows the whole structure of the molding machine used for this invention method. (A) is a principal part enlarged view before a deformation | transformation same as the above, (b) is a figure which shows the virtual line of an analysis model. It is a principal part enlarged view of a molding machine when an optical element material is deformed. It is a figure which shows the flowchart in this Embodiment. (A) is a cross-sectional front view of a pair of mold assemblies, and (b) is an enlarged view of part A thereof. (A) is a cross-sectional front view of a pair of mold assemblies, and (b) is an enlarged view of part B thereof. It is a cross-sectional front view of a pair of mold assemblies.

Explanation of symbols

7 Glass material 10 Mold assembly 11 Mold 11a Mold surface 12 Mold die 13 Die plate 14 Fixed shaft 15 Heat insulation cylinder 17 Seal plate 18 Gas supply flow path 20 Mold assembly 21 Mold 21a Mold surface 22 Mold die 22a Mold Die surface 23 Die plate 24 Fixed shaft 25 Heat insulation cylinder 27 Seal plate 28 Gas supply flow path 30 Transparent quartz tube 31 Molding chamber 32 Infrared lamp unit 33 Joint part 34 Joint part 100 after design change Molding machine

Claims (7)

In the optical element molding simulation method for simulating the molding process when molding the optical element by pressing the heat-softened optical element material,
Setting a simulation model having a pair of mold assemblies including a pair of molds arranged in opposition and an optical element material interposed between the pair of molds;
Of the mold members constituting the pair of mold assemblies, the approximate center of the joint portion between the molding die and the adjacent mold member is used as the coordinate of interest, and the distance from the coordinate of interest to the end of the joint portion, or Set the distance from the target coordinates to any position as the judgment area,
Within the determination region, an outer shape of each mold member at the joint, a virtual shape including a shape extending from the end to the target coordinate, and a contour of the optical element material at the final pressing position, Simulate contact pressure,
Comparing the simulated contact pressure with a predetermined contact pressure set in advance;
When the contact pressure is greater than the predetermined contact pressure, it is predicted that burrs will occur in the optical element material.
An optical element molding simulation method characterized by the above. The predetermined contact pressure was zero,
The optical element molding simulation method according to claim 1. Using the molding simulation method for an optical element according to claim 1 or 2,
When it is predicted that burrs will occur, the joint distance of the joint is changed.
A method for designing a molding die of an optical element. Using the molding simulation method for an optical element according to claim 1 or 2,
When it is predicted that burrs will occur, the joining position of the joint is changed.
A method for designing a molding die of an optical element. In the optical element molding simulation method for simulating the molding process when molding the optical element by pressing the heat-softened optical element material,
Setting a simulation model having a pair of mold assemblies including a pair of molds arranged in opposition and an optical element material interposed between the pair of molds;
Of the mold members constituting the pair of mold assemblies, the approximate center of the joint portion between the molding die and the adjacent mold member is used as the coordinate of interest, and the distance from the coordinate of interest to the end of the joint portion, or Set the distance from the target coordinates to any position as the judgment area,
Within the determination area, the outer shape of each mold member at the joint, the position coordinates of the virtual shape including the shape extending from the end to the target coordinate, and the contour of the optical element material at the final pressing position And the position coordinates of
When the position coordinates of the virtual shape in the simulated joint portion are compared with the position coordinates of the contour portion of the optical element material at the final pressing position, and include portions where the respective position coordinates match, Predict that burrs will occur in the element material,
An optical element molding simulation method characterized by the above. Using the molding simulation method for an optical element according to claim 5,
When it is predicted that burrs will occur, the joint distance of the joint is changed.
A method for designing a molding die of an optical element. Using the molding simulation method for an optical element according to claim 5,
When it is predicted that burrs will occur, the joining position of the joint is changed.
A method for designing a molding die of an optical element.