JP2008074675A - Method of producing die for forming optical element, and method for production of optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forming die production method which enables lead time reduction and cost saving in the production of a forming die material, the response to enhancement of the forming surface accuracy as a forming die, the securement of the comprehensive accuracy of the forming die and also enables to quickly, inexpensively provide a high-quality, high-performance optical element. <P>SOLUTION: The forming die 1 for an optical element is composed by firmly fixing the edge of a cylindrical reference form part 2 to that of a cylindrical forming die part 3 having a larger diameter than the reference form part 2 to integrate both parts 2 and 3. The forming die 1 for the optical element is installed to the major axis of a processing machine using the side of the reference form part 2 being a reference face as an opposition, and is subjected to centering adjustment concentrically with the major axis. Then, the diameter of the forming die part 3 is made to be equal to that of the reference form part 2 by processing the forming die part 3 using a grinding wheel 18, and thereafter, the forming face of the forming die part 3 is processed into a desired shape. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a molding technique, and relates to a method for manufacturing an optical element molding die for molding an optical element such as a lens and a method for manufacturing an optical element.

  In order to obtain an optical element such as a lens, there is a method in which a molding material for an optical element made of glass or plastic is placed between a pair of optical element molding dies, and this is molded hot (press molding or injection molding). Widely done.

  As a method of creating a molding die used in such molding, for example, cemented carbide, ceramics, or SUS material with electroless nickel plating is ground, cut and polished with an ultra-precision lathe. And a method of using a glass molding die obtained by pressing a glass material with the molding mother mold by producing a molding die in which a molding die is obtained in a desired shape.

With regard to such a technique, for example, Patent Document 1 discloses a method for manufacturing a glass molding die that performs molding so that a sliding outer shape with a body die is not regulated in a step of transferring a molding surface to a glass material. . According to Patent Document 1, a glass molding die base having a molding surface previously molded can be obtained in this manner, and therefore, for glass molding by performing a centering process on the basis of the molding surface. It is disclosed that total accuracy as a mold is improved and quality can be stabilized.
JP 2005-97009 A

However, there are the following problems in the above-described prior art regarding the manufacturing method of the mold.
First, in the technique of grinding, cutting and polishing cemented carbide, ceramics, or SUS material with electroless nickel plating using an ultra-precision lathe, the accuracy of the molding surface, the molding surface and the mold reference part Position accuracy (eccentricity accuracy) and overall accuracy are satisfactory as a mold such as a sliding part with a barrel mold orthogonal to the molding surface, but the production lead time of the molding material is long and the cost is high. It has become.

  In addition, since the technique disclosed in Patent Document 1 described above is to secure a molding surface by transferring a mother die, it is not sufficient to ensure accuracy as a molding die that requires high accuracy. That is, even if high accuracy is supported, it is necessary to process the master die with ultra-high accuracy, and it is difficult to ensure the accuracy. In addition, since the molding die is made of glass, the sliding surface on the movable side of the die is likely to chip and wear, and it is difficult to ensure sufficient positional accuracy (eccentricity accuracy) between the glass die reference surface and the molding surface. .

  The present invention has been made in view of the above-mentioned problems, and the problem to be solved is to suppress the production lead time and cost of the molding die material, and further to high accuracy of the molding surface as a molding die. It is to provide a manufacturing method of a molding die that can ensure the overall accuracy of the molding die and to provide high-quality and high-performance optical elements quickly and inexpensively.

  According to another aspect of the present invention, there is provided a method for manufacturing an optical element molding die, comprising: a reference mold part having a reference surface when molding an optical element; and a molding mold part having a molding surface for molding the optical element. In manufacturing an optical element molding die that is integrally formed, a step of integrating one end surface of the molding die portion having an outer diameter larger than the reference die portion and an end surface of the reference die portion; and the reference die A process of attaching the center axis of the reference mold part to the center axis of the molding die part by attaching the molding die part to the spindle of the processing machine using the reference surface of the part as a counter and processing the molding die part with the processing machine. And a step of processing the molding surface on the other end surface of the molding die, and this feature solves the above-described problems.

In the above-described method for manufacturing an optical element molding die according to the present invention, the reference mold part and the molding mold part may be cylindrical.
In the method for manufacturing an optical element molding die according to the present invention described above, the reference mold part is made of a metal, carbide or ceramic having heat resistance, and the molding mold part is linearly expanded with the reference mold part. You may consist of glass with a substantially equal coefficient.

  In the above-described method for manufacturing an optical element molding die according to the present invention, the step of integrating the molding die portion and the reference die portion may be performed by using a heated fusion bonding member as an end face of the molding die portion. You may make it fix by pressing with the end surface of the said reference | standard type | mold part.

  In the method for manufacturing an optical element molding die according to the present invention described above, the step of integrating the molding die portion and the reference die portion includes the end surface of the molding die portion and the end surface of the reference die portion. And may be fixed with an adhesive.

  In the method for manufacturing an optical element molding die according to the present invention described above, the step of processing the molding die portion with the processing machine may be performed such that the outer diameter of the molding die portion is equal to or smaller than the outer diameter of the reference die portion. You may make it.

Further, in the method for manufacturing an optical element molding die according to the present invention described above, the other end surface of the molding mold portion corresponds to the optical element before the molding die portion and the reference mold portion are integrated. You may make it process beforehand in the spherical shape approximated to the shape which carried out.

In addition, a molding material is arranged between a pair of optical element molding dies manufactured using the method for manufacturing an optical element molding dies according to the present invention described above, and this is molded by hot molding. An optical element manufacturing method characterized by obtaining the element also relates to the present invention.

  According to the present invention, the manufacturing lead time and cost of the molding die material can be suppressed by doing as described above, and further, the molding die can be used in combination with the improvement of the molding surface accuracy as a molding die. As a result of providing a method for manufacturing a mold capable of ensuring comprehensive accuracy, it is possible to provide a high-quality and high-performance optical element quickly and inexpensively.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a final finished state of an optical element molding die 1 which is a workpiece in this embodiment. This optical element molding die 1 has a cylindrical shape, a reference mold part 2 made of SUS (stainless steel) as a base material, and a molding mold part 3 made of glass having a linear expansion coefficient substantially equal to that of the reference mold part 2. Are integrally configured. In the present embodiment, the side surface of the reference mold portion 2 becomes the molding reference surface of the optical element molding die 1.

FIG. 2 is a cross-sectional view showing a schematic configuration of a press molding apparatus 4 for forming the optical element molding die 1 by fusing the end surface of the reference mold portion 2 and the one end surface of the molding die portion 3.
In FIG. 2, an upper mold 7 and a reference mold portion 2 are fitted to a cylindrical heating ring 6 in which a heater 5 is provided, and the upper mold 7 is vertically moved (shown in the figure). (In the direction of the arrow).

  On the joining surface 2 a of the reference mold part 2, a fusion bonding member 8 having substantially the same diameter as the reference mold part 2 and a molding mold part 3 made of glass having a diameter larger than that of the reference mold part 2 are set. . Under a state in which the entire press molding apparatus 4 is heated by the heater 5 provided in the heating ring 6, the upper mold 7 is moved downward by a desired pressing force by a press mechanism (not shown) connected to the upper mold 7. When sliding, the mold part 3 and the reference mold part 2 are firmly fused by the fusion bonding member 8.

FIG. 3 is a perspective view showing the configuration of the outer diameter (outer peripheral surface) 3b in the molding die portion 3 of the optical element molding die 1 shown in FIG. 1 and the ultraprecision processing machine 9 used for processing the molding surface 3a. .
This ultra-precision machine 9 has an X-axis table 10 and a Z-axis table 11 slidable in two directions of the X-axis and Z-axis, respectively, on an ultra-precision machine base 15, and further rotates the spindle 12. And a B-axis rotary table 14 for rotating the tool rotary spindle 13. That is, the ultraprecision machine 9 has a configuration capable of three-axis control with the X and Z axes as slide axes and the B axis as a rotation axis.

  The optical element molding die 1 is fixed to a main shaft 12 installed on a Z-axis table 11. Here, the Z-axis is an axis parallel to the rotation axis 12a of the main shaft 12, and the X-axis is an axis perpendicular to the rotation axis 12a.

  The tool rotating spindle 13 is fixed to a tool rotating spindle holder 17 installed on a B-axis rotating table 14 on the X-axis table 10 facing the Z-axis. Here, the B-axis is an axis perpendicular to the plane formed by the X-axis and the Z-axis, and the tool rotating spindle 13 is installed so as to be rotatable in the horizontal direction with respect to the rotating shaft 12a of the main shaft 12. ing.

FIG. 4 is a top view of the tool rotating spindle 13 to which the grinding wheel 18 is attached.
The grinding wheel 18 is attached to a tool rotating spindle 13 installed on the B-axis rotating table 14 of the ultraprecision machine 9. Here, the working point 18 a of the grinding wheel 18 and the rotating shaft 14 a of the B-axis rotary table 14 are matched with each other by an adjustment mechanism (not shown) of the tool spindle holder 17. The rotating shaft 13 a of the tool rotating spindle 13 and the rotating shaft 12 a of the main shaft 12 are also horizontally aligned by an adjustment mechanism (not shown) of the tool spindle holder 17.

Next, the process of processing the optical element molding die 1 will be described with reference to the process chart shown in FIG.
First, the optical element molding die 1 is fixed to the main shaft 12 of the ultraprecision machine 9. At this time, the outer diameter (side surface) 2b (see FIG. 1) of the reference mold part 2 that is a molding reference of the optical element molding die 1 is centered and adjusted coaxially with the rotary shaft 12a of the main shaft 12.

  Next, as shown as (1) in FIG. 5, the outer diameter 3 b (see FIG. 1) of the forming die portion 3 having a cylindrical shape is changed to a cylindrical shape by a grinding wheel 18 attached to the tool rotating spindle 13. Grinding is performed so as to have the same diameter as the outer diameter 2b of the reference mold part 2. That is, the central axis of the reference mold part 2 and the central axis of the molding mold part 3 are matched. At this time, the rotation axis 13a of the tool rotation spindle 13 and the rotation axis 12a of the main shaft 12 are parallel to each other, or within a range where the side surface of the grinding wheel 18 does not bite into the side surface of the molding die 3. Adjustment is performed with the shaft rotation table 14.

  Next, as shown as (2) in FIG. 5, the molding surface 3a (see FIG. 1) of the other end surface of the molding die portion 3 of the optical element molding die 1 is ground with a grinding wheel 18 from the flat surface. In this processing, the machining action point 18a of the grinding wheel 18 aligned with the rotary shaft 14a of the B-axis rotary table 14 and the rotary shaft 12a of the main shaft 12 is converted into a CNC (computer numerical control) of a super-precision machine 9 (not shown). The scanning is performed in a desired shape by three-axis control of the X, Z, and B axes by the apparatus.

Thereafter, as shown in FIG. 5 as (3), polishing is performed using a polishing tool 19 to finish the molding surface 3a with high accuracy.
As described above, according to the present embodiment, by using the reference mold part 2 having a simple shape and the molding mold part 3 made of a glass material, the manufacturing cost and the lead of the material as the optical element molding mold 1 are obtained. Time can be suppressed. Further, the outer diameter 2b, which is a molding reference in the reference mold part 2, is used as an axis, and the diameter of the reference mold part 2 and the diameter of the molding mold part 3 are coaxially processed, and then the molding surface 3a of the molding mold part 3 is formed. By manufacturing the optical element molding die 1 by processing into a desired shape, the accuracy of the molding surface 3a, the positional accuracy of the molding surface 3a and the mold reference portion 2, and the sliding with the barrel die orthogonal to the molding surface 3a. It is possible to obtain high overall accuracy as a molding die, such as matching of parts.

  FIG. 6 shows a final finished state of the optical element molding die 20 which is a workpiece in this embodiment. In this optical element molding die 20, a reference mold portion 21 made of SUS material as a base material and a molding die 22 made of glass whose linear expansion coefficient is substantially equal to the reference mold portion 21 are integrally formed. . This is the same as the optical element molding die 1 in the first embodiment. However, the optical element molding die 20 is different from the molding die portion 3 in that the diameter of the cylindrical molding portion 22 is smaller than the diameter of the reference cylindrical portion 21 which is also cylindrical. This is different from the optical element molding die 1 of Example 1 which is formed so as to have the same diameter as the reference mold part 2.

In the present embodiment, the side surface of the reference mold portion 21 becomes the molding reference surface of the optical element molding die 10.
FIG. 7 shows a blank state of the optical element molding die 20. The molding die 22 has a molding surface 22a, which is one end surface (the other end surface), processed in advance with an approximate R (spherical surface) close to a desired shape, and the other end surface facing the molding surface 22a. The end face of the reference mold part 21 is firmly bonded with a heat resistant adhesive 23. At this time, the diameter of the molding die 22 is larger than that of the reference die 21.

FIG. 8 is a perspective view showing the configuration of an ultra-precision machine 9 ′ used for processing the molding surface 22a of the molding die 22 of the optical element molding die 20 shown in FIG.
The configuration of the ultraprecision machine 9 ′ and the ultraprecision machine 9 shown in FIG. 3 are different in that the tool rotating spindle 13 and the tool spindle holder 17 are replaced with a vibration cutting device 24. The vibration cutting device 24 installed on the B-axis rotary table 14 of the ultra-precision machine 9 ′ is a device that performs cutting using vibration, and includes a centered diamond tool 25.

  FIG. 9 is a top view of the vibration cutting device 24 to which the diamond tool 25 is attached. Here, the cutting edge operating point 25a of the diamond tool 25 and the rotating shaft 14a of the B-axis rotary table 14 are matched with each other by an adjusting mechanism (not shown). The cutting edge rake face of the diamond tool 25 and the rotating shaft 12a of the main shaft 12 are also horizontally aligned by an adjustment mechanism (not shown).

The other configurations of the ultraprecision machine 9 ′ shown in FIG. 8 are the same as those of the ultraprecision machine 9 shown in FIG.
Next, the process of processing the optical element molding die 20 will be described with reference to the process diagram shown in FIG.

  First, the optical element molding die 20 is fixed to the main shaft 12 of the ultraprecision machine 9 '. At this time, the outer diameter 21a (see FIG. 7) of the reference mold portion 21 that serves as a molding reference for the optical element molding die 20 is used as a center and adjusted to be coaxial with the rotary shaft 12a of the main shaft 12.

  Next, as shown as (1) in FIG. 10, the outer diameter 22 b (see FIG. 7) of the molding die 22 is changed to the outer diameter 21 a of the reference die 21 by the diamond tool 25 attached to the vibration cutting device 24. Cutting is performed so as to be more negative (that is, the diameter of the molding die portion 22 is smaller than the diameter of the reference die portion 21). Note that the negative value at this time is preferably a value that does not allow the resin to enter during molding of the optical element, and specifically 50 μm or less is desirable.

  Next, as shown as (2) in FIG. 10, the molding surface 22 a (see FIG. 7) of the molding die portion 22 of the optical element molding die 20 is cut with a diamond tool 25. This processing is performed by causing the diamond tool 25 that has been aligned to scan in a desired shape by three-axis control of the X, Z, and B axes by the CNC device of the ultra-precision machine 9 '(not shown).

Thereafter, as shown in FIG. 10 as (3), a polishing process is performed using a polishing tool 19 to finish the molding surface 22a with high accuracy.
As described above, according to the present embodiment, the optical element molding die 20 having high total accuracy can be obtained as in the first embodiment. Furthermore, according to the present embodiment, the optical element molding die 20 is manufactured by processing the diameter of the molding die portion 22 so as to be smaller than the diameter of the reference die portion 21, so that the optical mold can be moved to the movable side of the molding die. Even if the element molding die 20 is used, the sliding surface will not be chipped or worn, and the positional accuracy of the molding surface 22a can be ensured. In addition, the optical element molding die 20 is manufactured by using the molding die portion 22 that has been processed in advance to approximate the optical element shape R in which the molding surface 22a has a desired shape before the integration with the reference die portion 21. By doing so, the processing lead time of the molding surface 22a can be reduced.

  By the way, in order to manufacture an optical element using the optical element molding die 1 or 20 manufactured as described above, a molding material for an optical element made of glass or plastic is used as a pair of optical element molding molds 1 or 20. It may be disposed between 20 and molded (press molding or injection molding) while hot.

As mentioned above, although embodiment of this invention was described, this invention is not limited to each embodiment mentioned above, A various improvement and change are possible within the range which does not deviate from the summary of this invention.
For example, in each of the above-described embodiments, the reference mold parts 2 and 21 that are SUS materials are used. However, the material of the reference mold parts 2 and 21 may be used as long as it has heat resistance during optical element molding. Any of metal, cemented carbide, ceramics and the like may be used.

  In Example 2 described above, the optical element molding die 20 is manufactured by processing the diameter of the molding die portion 22 so as to be smaller than the diameter of the reference die portion 21. It is of course possible to manufacture the optical element molding die 20 by processing the diameter so as to be the same as that of the reference die portion 21.

2 is a diagram illustrating a final finished state of the optical element molding die in Example 1. FIG. It is sectional drawing which shows schematic structure of a press molding apparatus. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a configuration of an ultraprecision machine used in Example 1. It is a figure which shows the upper side figure of the tool rotation spindle which attached the grinding wheel. FIG. 6 is a process diagram illustrating a process of processing an optical element molding die in Example 1. 6 is a diagram illustrating a final finished state of an optical element molding die in Example 2. FIG. It is a figure which shows the blank state of the optical element shaping die in Example 2. FIG. It is a perspective view which shows the structure of the ultraprecision processing machine used in Example 2. FIG. It is a top view of the vibration cutting apparatus to which the diamond tool is attached. 6 is a process diagram showing a process of processing an optical element molding die in Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,20 Optical element shaping | molding die 2, 21 Reference | standard type | mold part 2a Reference | standard type | mold part joining surface 2b, 21a Reference | standard type | mold part outer diameter 3, 22 Molding type | mold part 3a, 22a Molding type | mold part molding surface 3b, 22b Molding type External diameter 4 Press forming device 5 Heater 6 Heating ring 7 Upper mold 8 Fusion bonding member 9, 9 'Ultra-precision processing machine 10 X-axis table 11 Z-axis table 12 Spindle 12a Spindle rotation shaft 13 Tool rotation spindle 13a Tool rotation Spindle rotating shaft 14 B-axis rotating table 14a B-axis rotating table rotating shaft 15 Super precision processing machine base 16 Spindle rotating motor 17 Tool rotating spindle holder 18 Grinding wheel 18a Grinding wheel working point 19 Polishing tool 23 Heat resistant adhesive 24 Vibration cutting Equipment 25 Diamond tool 25a Diamond tool cutting edge working point

Claims (8)

In manufacturing an optical element molding die that integrally constitutes a reference mold part having a reference surface when molding an optical element and a molding mold part having a molding surface for molding the optical element,
Integrating the one end surface of the molding die portion having an outer diameter larger than that of the reference die portion and the end surface of the reference die portion;
A reference surface of the reference mold part is attached to a main shaft of a processing machine as a counter, and the molding mold part is processed by the processing machine to obtain a central axis of the reference mold part and a central axis of the molding mold part. A matching step;
Processing the molding surface on the other end surface of the molding die,
A process for producing an optical element molding die characterized by comprising:   The method for manufacturing an optical element molding die according to claim 1, wherein the reference mold part and the molding mold part have a cylindrical shape.   3. The reference mold part according to claim 1, wherein the reference mold part is made of heat-resistant metal, cemented carbide or ceramics, and the molding mold part is made of glass having a linear expansion coefficient substantially equal to that of the reference mold part. The manufacturing method of the optical element shaping | molding die of description.   The step of integrating the molding die and the reference die is characterized by pressing and fixing the heated fusion bonding member between the end surface of the molding die and the end surface of the reference die. The manufacturing method of the optical element shaping | molding die as described in any one of Claims 1-3.   2. The step of integrating the molding die and the reference die is characterized by adhering and fixing the end surface of the molding die and the end surface of the reference die with an adhesive. 4. A method for producing an optical element molding die according to any one of items 1 to 3.   6. The step of processing the molding die portion with the processing machine sets an outer diameter of the molding die portion to be equal to or smaller than an outer diameter of the reference die portion. The manufacturing method of the type | mold for optical element shaping | molding of description.   Before integrating the molding die portion and the reference die portion, the other end surface of the molding die portion is processed in advance into a spherical shape approximate to a shape corresponding to the optical element. The manufacturing method of the optical element shaping | molding die as described in any one of Claims 1-6.   A molding material is disposed between a pair of optical element molding dies manufactured using the method for manufacturing an optical element molding dies according to any one of claims 1 to 7, and the molding material is heated. An optical element manufacturing method, wherein an optical element is obtained by molding in between.