JP2016138008A - Set for molding glass optical element, and manufacturing method of glass optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately mold a glass optical element by stabilizing release of a glass molding raw material from a molding die, in a set for molding the glass optical element and a manufacturing method of the glass optical element.SOLUTION: A set 100 for molding a glass optical element includes an upper die 101 (first molding die) and a lower die 102 (second molding die) that are arranged oppositely to each other so as to sandwich a glass molding raw material 201, and an auxiliary shell die 104 (third molding die) arranged between the upper die 101 and the lower die 102. The upper die 101 and the lower die 102 have molding surfaces 101a and 102a respectively of which the surface shape is transferred to an optical-function face of the glass molding raw material 201. The auxiliary shell die 104 has a molding surface 104a of which the surface shape is transferred to the outer peripheral surface of the glass molding raw material 201, which is not an optical-function face. The molding surface 104a of the auxiliary shell die 104 has an arithmetic average roughness Ra of 200 nm or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a glass optical element molding mold set and a method for producing a glass optical element using the glass optical element molding mold set.

  In recent years, glass optical elements such as lenses, prisms, and mirrors have been required to have high performance and high functionality. For example, a method for improving the performance by changing the optical surface shape to an aspherical shape is known. In particular, in the case of mass production of a glass optical element having an aspherical shape, a manufacturing method is employed in which a heat-softened glass molding material is pressure-molded with a molding die.

Although not limited to a glass optical element having an aspherical shape, a manufacturing apparatus suitable for mass production of glass optical elements includes the following.
For example, a glass optical element manufacturing apparatus that manufactures a desired glass optical element by sequentially conveying glass forming materials contained in a glass optical element forming mold set to heating, pressure forming, and cooling stages is known. It has been. The glass optical element molding mold set includes, for example, an upper mold, a lower mold, a trunk mold, and an auxiliary trunk mold. The trunk mold is a cylindrical member positioned around the upper mold and the lower mold, and the auxiliary trunk mold is a cylindrical member positioned between the upper mold and the lower mold.

  In such a mold set for glass optical element molding, in order to reduce the variation of the molding shape and obtain a stable and highly accurate glass optical element, the arithmetic average roughness Ra of the optical functional surface is 0.3 nm or more and 30 nm or less. There is a known technique (see, for example, Patent Document 1).

  In the glass optical element molding die set, the maximum height roughness Rmax of the optical function surface is set to 100 nm or less (equivalent to arithmetic average roughness Ra of 25 nm or less), and the maximum height roughness Rmax of the non-optical function surface is set to 1600 nm or more and 6300 nm. The following method (arithmetic average roughness Ra corresponding to 400 nm or more and 1600 nm or less) is known (for example, see Patent Document 2).

JP-A-2005-330152 JP 2001-335330 A

  By the way, in the non-optical functional surface such as the inner peripheral surface of the auxiliary cylinder type, when the maximum height roughness Rmax is a large value such as the above 1600 nm or more and 6300 nm or less (equivalent to the arithmetic average roughness Ra 400 nm or more and 1600 nm or less), Since the contact area between the glass forming material and the auxiliary cylinder mold is reduced, mold release in the cooling process is likely to occur at a relatively early stage. On the other hand, when the glass molding material is rarely filled in the rough portion of the auxiliary cylinder mold, the glass molding material is likely to stick to the auxiliary cylinder mold due to the influence of the anchor effect. And in the site | part where sticking generate | occur | produced, it becomes difficult to release compared with a smooth site | part.

  Thus, when the maximum height roughness Rmax is a large value such as the above-mentioned arithmetic average roughness Ra of 400 nm or more and 1600 nm or less (corresponding to 1600 nm or more and 6300 nm or less), the mold release becomes faster or slower. The state is likely to change. In particular, when the glass molding material is in a state of being easily stuck to the auxiliary cylinder mold, there arises a problem that cracks, cans, image sticking, etc. occur on the outer peripheral surface of the glass optical element.

  In addition, since the release timing of the glass optical element and the auxiliary cylinder mold differs depending on the part, the time for heat conduction between the auxiliary cylinder mold and the glass optical element is shorter in the part released first than in the part released later. Become. As a result, the temperature changes between the part released first and the part released later. This temperature change affects not only the outer peripheral surface of the glass optical element but also the region such as the optical functional surface located inside the outer peripheral surface. For this reason, variations in surface shape occur on the optical function surface for which higher precision is required, and the occurrence of asses, frames, and habits increases.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a glass optical element molding die set and a method for manufacturing a glass optical element, which can mold a glass optical element with high precision by stabilizing the release of the glass molding material and the mold. Is to provide.

  In one aspect, the glass optical element molding die set is disposed so as to face each other with the glass molding material interposed therebetween, and has a molding surface that has a molding surface that transfers a surface shape to the optical function surface of the glass molding material. And a molding surface which is disposed between the second molding die and the first molding die and the second molding die, and which transfers a surface shape to an outer peripheral surface which is a non-optical functional surface of the glass molding material. The arithmetic average roughness Ra of the molding surface of the third molding die is Ra ≦ 200 nm.

  In another aspect, the method for producing a glass optical element includes a heating step of heating a glass molding material accommodated in a glass optical element molding die set, and pressurization for pressing the heated glass molding material. A molding step and a cooling step for cooling the pressure-molded glass molding material, wherein the glass optical element molding die set is arranged to face each other with the glass molding material sandwiched therebetween, and the glass molding A first molding die having a molding surface for transferring a surface shape to the optical functional surface of the material and the second molding die, and disposed between the first molding die and the second molding die; A third molding die having a molding surface for transferring the surface shape to the outer peripheral surface which is a non-optical functional surface of the glass molding material, and the arithmetic mean roughness Ra of the molding surface of the third molding die is Ra ≦ 200 nm.

  According to the said aspect, a glass optical element can be shape | molded with high precision by stabilizing the mold release of a glass forming raw material and a 3rd shaping | molding die.

(A) And (b) is sectional drawing which shows the type | mold set for glass optical element shaping | molding which concerns on one embodiment of this invention. (A) And (b) is the top view and AA sectional drawing which show the auxiliary | assistant cylinder type | mold in one embodiment of this invention. (A) And (b) is the top view and BB sectional drawing which show the auxiliary | assistant cylinder type | mold in the modification of one embodiment of this invention. It is a figure which shows arithmetic mean roughness Ra of the molding surface of the auxiliary | assistant cylinder type | mold in one embodiment of this invention. It is explanatory drawing for demonstrating an example of the grinding process of the molding surface of the auxiliary cylinder type | mold in one embodiment of this invention. It is explanatory drawing for demonstrating an example of the grinding | polishing process of the molding surface of the auxiliary cylinder type | mold in one embodiment of this invention. It is a front view which shows the internal structure of the manufacturing apparatus of the glass optical element in one embodiment of this invention.

  Hereinafter, a glass optical element molding die set and an optical element manufacturing method according to embodiments of the present invention will be described with reference to the drawings.

<Glass optical element molding die set>
FIGS. 1A and 1B are cross-sectional views showing a glass optical element molding die set (hereinafter, simply referred to as “die set”) 100 according to an embodiment of the present invention. .

  As shown in FIGS. 1A and 1B, the mold set 100 includes an upper mold 101, a lower mold 102, a trunk mold 103, and an auxiliary trunk mold 104. The upper mold 101 and the lower mold 102 are an example of a first mold and a second mold. The auxiliary cylinder mold 104 is an example of a third mold.

The upper mold 101 and the lower mold 102 are disposed so as to face each other with the glass molding material 201 interposed therebetween. The upper mold 101 and the lower mold 102 have, for example, a cylindrical shape.
The upper mold 101 has, for example, a concave molding surface 101a formed on the bottom surface. The lower mold 102 has a concave molding surface 102a formed on the upper surface. These molding surfaces 101a and 102a transfer the surface shape to the optical function surface (surface that exhibits optical characteristics) of the glass optical element 202 (glass molding material 201) shown in FIG. The molding surfaces 101a and 102a transfer the surface shape not only to the optical functional surface of the glass optical element 202 but also to the non-optical functional surfaces located around the molding optical surfaces.

A stepped portion 101 b is formed at the upper end of the upper mold 101. A stepped portion 102 b is also formed at the lower end of the lower mold 102.
The trunk mold 103 has a cylindrical shape. The body mold 103 is disposed around the upper mold 101 and the lower mold 102 between the stepped portion 101 b of the upper mold 101 and the stepped portion 102 b of the lower mold 102. The upper mold 101 is slidable with respect to the inner peripheral surface of the body mold 103 on the outer peripheral surface.

  As shown in FIG. 2A, which is a plan view, and FIG. 2B, which is a cross-sectional view taken along the line AA, the auxiliary body mold 104 is formed with, for example, a ring shape (or a cylindrical shape, or a through hole). Columnar shape). The auxiliary trunk mold 104 is disposed between the upper mold 101 and the lower mold 102 in the hollow portion of the trunk mold 103. The auxiliary body mold 104 may be provided integrally with the body mold 103.

  The auxiliary cylinder mold 104 has a molding surface 104a on its inner peripheral surface for transferring the surface shape to the outer peripheral surface which is a non-optical functional surface of the glass optical element 202 (glass molding material 201). Note that the outer peripheral surface of the glass molding material 201 is a portion excluding a portion where the surface shape is transferred by the molding surfaces 101 a and 102 a of the upper mold 101 and the lower mold 102.

  As shown in FIG. 3, a protective film 105 (indicated by a thick solid line in FIG. 3) may be formed on the molding surface 104 a of the auxiliary cylinder mold 104. Examples of the material of the protective film 105 include noble metal systems such as platinum, rubidium, iridium, palladium, ruthenium, osnium, and gold, and carbon. In addition, since the protective film 105 is formed with a substantially uniform film thickness, the surface roughness of the molding surface 104 a of the auxiliary cylinder mold 104 appears on the protective film 105 to some extent.

  As shown in FIG. 4, the arithmetic average roughness Ra of the molding surface 104a of the auxiliary cylinder 104 is Ra ≦ 200 nm (in FIG. 4, 0.2 [μm]). More preferably, the arithmetic average roughness Ra of the molding surface 104a is Ra ≦ 60 nm. Note that the solid line extending to the left and right in the vicinity of −0.02 [μm] in FIG. 4 is an average line of the roughness curve at the reference length. The above relationship of the arithmetic average roughness Ra is satisfied regardless of whether the reference length in the thickness direction of the glass forming material 201 or the reference length in the circumferential direction of the glass forming material 201 orthogonal to the thickness direction is compared.

  The arithmetic average roughness Ra of the molding surface 104a is preferably 1 nm ≦ Ra. Although Ra may be less than 1 nm, it is because the glass molding material 201 becomes easy to stick to the molding surface 104a. The arithmetic average roughness of the portion of the molding surfaces 101 a and 102 a of the upper mold 101 and the lower mold 102 that transfers the surface shape to the optical functional surface of the glass optical element 202 is the arithmetic average of the molding surface 104 a of the auxiliary cylinder 104. It is desirable to be less than or equal to the roughness.

  In the distribution of the arithmetic average roughness Ra around the glass forming material 201 on the molding surface 104a of the auxiliary cylinder 104, the difference ΔRa between the maximum value and the minimum value is ΔRa ≦ 50 nm. More preferably, ΔRa is ΔRa ≦ 30 nm. Note that this relationship of ΔRa is satisfied in both of the following two cases. The first is the roughness in the reference length in the thickness direction of the glass forming material 201 and the thickness direction of the glass forming material 201 at other positions away from the position of the reference length in the circumferential direction of the glass forming material 201. This is a case where the roughness at the reference length is compared. The second is the roughness at the reference length in the circumferential direction of the glass forming material 201 and the circumference of the glass forming material 201 at other positions away from the position of the reference length in the circumferential direction of the glass forming material 201. This is a case of comparing with the roughness at the reference length in the direction.

  As will be described later, when the rotational feed direction of the molding surface 104a of the auxiliary cylinder 104 is the circumferential direction of the molding surface 104a (glass molding material 201), the linear feeding direction (glass molding material 201) orthogonal to this circumferential direction. In the thickness direction), Ra and ΔRa are likely to increase. The arithmetic average roughness Ra shown in FIG. 4 is a measurement result in the thickness direction of the glass forming material 201 that is the linear feed direction.

FIGS. 5 and 6 are explanatory views for explaining an example of grinding and polishing of the molding surface 104a of the auxiliary cylinder 104. FIG.
In order to finish the arithmetic average roughness Ra and ΔRa of the molding surface 104a of the auxiliary cylinder 104 so as to satisfy the above relationship, the grinding process shown in FIG. 5 is preferably performed. In the example of FIG. 5, the auxiliary cylinder mold 104 or the tool 301 having the grindstone 301a rotates around the central axis C11 of the auxiliary cylinder mold 104 (rotational feed), and the tool 301 rotates about the central axis C12. Further, the tool 301 or the auxiliary cylinder 104 is moved in parallel with the central axes C11 and C12 as appropriate (linear feed). In order to reduce the arithmetic average roughness Ra of the molding surface 104a, it may be appropriately adjusted by selecting a grindstone or slowing the feed rate. Prior to the grinding process, for example, a process such as cutting the auxiliary body mold 104 into a rough cylindrical shape is appropriately performed.

  Further, in order to reduce the arithmetic average roughness Ra and ΔRa of the molding surface 104a of the auxiliary cylinder 104, a polishing process shown in FIG. 6 may be performed after the grinding process. In the example of FIG. 6, the auxiliary cylinder mold 104 or the tool 302 having the contact portion 302 a rotates (rotational feed) around the central axis C <b> 21 of the auxiliary cylinder mold 104, and the tool 302 rotates around the central axis C <b> 22. To do. Further, the tool 302 or the auxiliary cylinder 104 is moved in parallel with the central axes C21 and C22 as appropriate (linear feed). An abrasive 303 is supplied onto the molding surface 104a of the auxiliary cylinder mold 104.

  The material of the above-described mold set 100 (the upper mold 101, the lower mold 102, the trunk mold 103, and the auxiliary trunk mold 104) uses, for example, cemented carbide, silicon carbide, stainless steel, etc. from the viewpoint of heat resistance and load resistance. Good. Further, mold film coating is performed on the molding surfaces 101 a and 102 a of the upper mold 101 and the lower mold 102 from the viewpoint of durability and releasability between the glass molding material 201 and the upper mold 101 and the lower mold 102. It is good. Furthermore, in order to improve the mold releasability of the molding surfaces 101a and 102a, the molding surfaces 101a and 102a may be subjected to a surface treatment using a release agent by physical or chemical means. Further, as the glass forming material 201, L-BSL7 (manufactured by OHARA INC., Glass transition point 498 ° C., yield point 549 ° C.) is known as an example.

<About the manufacturing method of a glass optical element>
First, an example of a glass optical element manufacturing apparatus used in the glass optical element manufacturing method will be described with reference to FIG.

FIG. 7 is a front view showing the internal structure of the glass optical element manufacturing apparatus 1 according to the embodiment of the present invention.
The glass optical element manufacturing apparatus 1 shown in FIG. 7 includes a molding chamber 2, a heating stage 10, a pressure molding stage 20, a cooling stage 30, a loading side mounting table 40, and a discharging side mounting table 50. Prepare.

The molding chamber 2 includes a shielding plate 2a, a closing shutter 2b, a discharging shutter 2c, and an internal shutter 2d.
The shielding plate 2 a is disposed inside the molding chamber 2, a space (preliminary chamber) in which the input side mounting table 40 is disposed, the heating stage 10, the pressure molding stage 20, the cooling stage 30, and the discharge side mounting table 50. Partition the space (molding space) where the

  The input-side shutter 2b is controlled to be opened when the mold set 100 is input into the molding chamber 2. Further, the discharge-side shutter 2c is controlled so as to be opened when the mold set 100 is discharged from the molding chamber 2. The molding chamber 2 is hermetically sealed by a closing shutter 2b and a discharging shutter 2c.

The inside of the molding chamber 2 is the atmosphere, or is replaced with an inert gas (Ar gas or the like) or nitrogen gas (N ₂ or the like). When an inert gas or nitrogen gas is used, gas is supplied into the molding chamber 2 through a pipe (not shown).

In the molding chamber 2, the plurality of mold sets 100 are successively transferred in the order of the input side mounting table 40, the heating stage 10, the pressure forming stage 20, the cooling stage 30, and the discharge side mounting table 50.
The heating stage 10, the pressure molding stage 20, and the cooling stage 30 have a pair of lower stage units 11, 21, 31 and upper stage units 12, 22, 32, and pressure units 13, 23, 33.

The lower stage units 11, 21, 31 and the upper stage units 12, 22, 32 are arranged to face each other so as to sandwich the mold set 100.
The lower stage units 11, 21, 31 include temperature control blocks 11a, 21a, 31a and heat equalizing members 11b, 21b, 31b. Similarly, the upper stage units 12, 22, and 32 also include temperature control blocks 12a, 22a, and 32a, and heat equalizing members 12b, 22b, and 32b.

In the temperature control blocks 11a, 21a, 31a, 12a, 22a, and 32a, for example, three cartridge heaters as an example of a heating source are arranged.
The soaking members 11b, 21b, 31b, 12b, 22b, and 32b have, for example, a plate shape or a block shape, and are positioned closer to the mold set 100 than the temperature control blocks 11a, 21a, 31a, 12a, 22a, and 32a. The soaking members 11b, 21b, 31b, 12b, 22b, 32b abut on the mold set 100.

  The pressurization units 13, 23, and 33 are molds that are transported between the upper stage units 12, 22, and 32 and the lower stage units 11, 21, and 31 by moving the upper stage units 12, 22, and 32 up and down. The set 100 and then the glass forming material 201 shown in FIGS. 1A and 1B are pressurized.

  The lower stage units 11, 21, 31 are fixed to a base portion on the bottom surface in the molding chamber 2. Moreover, between the lower stage units 11, 21, 31 and the base part, and the upper stage units 12, 22, 32 and the pressurizing part 13, so that heat is not easily transmitted to the entire glass optical element manufacturing apparatus 1. A heat insulating block or a cooling block may be interposed between 23 and 33.

  Further, in the glass optical element manufacturing apparatus 1, piping for flowing cooling water may be installed around the base part and the pressurizing parts 13, 23, 33 in order to prevent overheating or stabilize the temperature. . In the glass optical element manufacturing apparatus 1, operation control of each unit and temperature control of the lower stage units 11, 21, 31 and the upper stage units 12, 22, 32 are performed by a control unit (not shown).

  Note that the heating stage 10, the pressure forming stage 20, and the cooling stage 30 may be subdivided for finer control. For example, a part or all of the heating stage 10, the pressure molding stage 20, and the cooling stage 30 may be arranged in plurality. Alternatively, a single stage that performs the heating process and the pressure molding process and a single stage that serves both as the pressure molding process and the cooling process may be arranged to provide two stages.

Hereinafter, a method for manufacturing an optical element according to the present embodiment will be described with reference to FIGS.
The process of manufacturing the glass optical element 202 from the glass molding material 201 using the mold set 100 includes the assembly process, heating process, pressure molding process, cooling process, and decomposition process of the mold set 100. Usually, the assembly process and the disassembly process of the mold set 100 are performed outside the glass optical element manufacturing apparatus 1. In the glass optical element manufacturing apparatus 1, a heating process, a pressure molding process, and a cooling process are sequentially performed.

<Assembly process>
First, the assembly process of the mold set 100 will be described.
As shown in FIG. 1 (a), with the auxiliary cylinder mold 104 placed on the upper surface of the lower mold 102, for example, a ball-shaped glass molding material 201 is placed in the hollow portion of the auxiliary cylinder mold 104 to form the lower mold 102. Place on surface 102a. In this state, the body mold 103 is fitted around the lower mold 102 and the auxiliary body mold 104, and the upper mold 101 is arranged so that the molding surface 101a faces the glass molding material 201 on the lower mold 102. To do.

  In this manner, the assembly of the mold set 100 is completed by sandwiching the glass molding material 201 between the upper mold 101 and the lower mold 102 that are inserted to face the body mold 103. Thereafter, the assembled mold set 100 is arranged on the input side of the glass optical element manufacturing apparatus 1 and sequentially input into the molding chamber 2 with the input side shutter 2b opened.

<Heating process>
Next, a heating process for heating the glass forming material 201 will be described.
Before the mold set 100 is transferred to the molding space in which the pressure molding stage 20 and the like are arranged in the molding chamber 2, the mold set 100 is a space (preliminary chamber) in which the input side mounting table 40 is arranged. Is replaced by nitrogen gas.

Thereafter, the internal shutter 2d of the shielding plate 2a is opened before the mold set 100 is transferred to the heating stage 10, and the internal shutter 2d is closed after the transfer is completed.
The mold set 100 is transferred from the input side mounting table 40 onto the lower stage unit 11 of the heating stage 10 by a transfer robot. Then, the upper stage unit 12 of the heating stage 10 is lowered by driving the pressure unit 13.

The mold set 100 is held while being sandwiched between the lower stage unit 11 and the upper stage unit 12.
The mold set 100 shown in FIG. 1A and the glass molding material 201 accommodated in the mold set 100 reach a molding temperature corresponding to the glass molding material 201 via the lower stage unit 11 and the upper stage unit 12. For a predetermined time. This molding temperature is set to a temperature higher than the yield point temperature of the glass used for the glass molding material 201. Thereby, the glass molding material 201 will be in a softened state under molding temperature. When the above heating step is completed, the upper stage unit 12 is raised by driving the pressure unit 13.

<Pressure forming process>
Next, a pressure molding process for pressure molding the heated optical material 201 will be described.
The mold set 100 is transferred from the lower stage unit 11 of the heating stage 10 to the lower stage unit 21 of the pressure forming stage 20 by a transfer robot. Then, the upper stage unit 22 of the pressure molding stage 20 is lowered by driving the pressure unit 23.

The mold set 100 shown in FIG. 1A is pressurized between the lower stage unit 21 and the upper stage unit 22 while being held at the molding temperature.
As shown in FIG. 1B, in the mold set 100, the glass molding material 201 sandwiched between the upper mold 101 and the lower mold 102 is deformed while the upper mold 101, the lower mold 102, and the auxiliary cylinder mold. The space surrounded by 104 fills up.

If pressing of the upper stage unit 22 is stopped when the desired shape of the glass optical element 202 is obtained from the ball-shaped glass molding material 201, the pressure molding is completed.
In order to obtain a desired shape of the glass optical element 202, the amount of movement of the upper stage unit 22 is controlled when the mold set 100 is pressurized between the lower stage unit 21 and the upper stage unit 22 as described above. Alternatively, the pressing force and the pressurizing time may be set and controlled. When the above-described pressure forming step is completed, the upper stage unit 22 is raised by driving the pressure unit 23.

<Cooling process>
Next, a cooling process for cooling the pressure-molded glass molding material 201 will be described.
The mold set 100 is transferred from the lower stage unit 21 to the lower stage unit 31 of the cooling stage 30 by the transfer robot. Then, the upper stage unit 32 of the cooling stage 30 is lowered by driving the pressure unit 33.

  The temperature of the lower stage unit 31 and the upper stage unit 32 is maintained at a temperature at which the mold set 100 and the glass molding material 201 can be cooled by the temperature control blocks 31a and 32a. Usually, the cooling temperature is set to a temperature lower than the glass transition point of the glass forming material 201.

  The mold set 100 is cooled to the cooling temperature while being held between the lower stage unit 31 and the upper stage unit 32. In the cooling step, the pressure is maintained by applying a cooling pressure so that the glass molding material 201 in the softened state is not solidified from the upper mold 101 and the lower mold 102 until the glass molding material 201 is sufficiently solidified. In particular, in order to control the mold release timing, it is effective to increase the cooling pressure and rapidly reduce the pressure immediately before being conveyed to the adjacent shaft.

  At the time of cooling, a pressurized state may be necessary to ensure the transfer accuracy of the molded glass optical element 202. In addition, the applied pressure at the time of cooling is set in a range in which the glass optical element 202 which is a molded product is broken or broken and does not break.

In the cooling step, the glass molding material 201 is shifted from the softened state to the solidified state, and the shape of the glass optical element 202 is stabilized.
When the mold set 100 and the glass molding material 201 are cooled, the upper stage unit 32 is raised by driving the pressure unit 33.

  The mold set 100 is transferred from the lower stage unit 31 of the cooling stage 30 onto the discharge side mounting table 50 by a transfer robot. And the type | mold set 100 waits on the discharge side mounting base 50, and is fully cooled. In the cooling process described above, the glass molding material 201 contracts and is released from the auxiliary cylinder mold 104 and the like of the mold set 100.

<Disassembly process>
Next, a disassembling process for disassembling the mold set 100 and taking out the manufactured glass optical element 202 will be described.

  The mold set 100 is discharged out of the molding chamber 2 from the discharge side mounting table 50 with the discharge side shutter 2c opened. Thereafter, the mold set 100 is disassembled in the reverse order of the assembly process. A molded glass optical element 202 is obtained from the disassembled mold set 100.

  By repeating the above steps, it is possible to manufacture a glass optical element using the mold set 100 cyclically. If a plurality of mold sets 100 are continuously put into the molding chamber 2 and used, the number of molded glass optical elements 202 per unit time can be improved.

  In the present embodiment, a method of manufacturing the glass optical element 202 in which the mold set 100 is circulated through the stages 10, 20, and 30 is described. However, when the upper mold 101 and the lower mold 102 are respectively fixed above and below a single stage, the upper mold 101 and the lower mold 102 are disposed on the upper mold 101, for example. The auxiliary cylinder mold 104 functions as the mold set 100.

  In the present embodiment described above, the mold set 100 includes an upper mold 101 and a lower mold 102 (an example of a first molding mold and a second molding mold) disposed so as to face each other with the glass molding material 201 interposed therebetween. And an auxiliary cylinder mold 104 (an example of a third molding mold) disposed between the upper mold 101 and the lower mold 102. The upper mold 101 and the lower mold 102 have molding surfaces 101 a and 101 b that transfer the surface shape to the optical function surface of the glass molding material 201. In addition, the auxiliary cylinder mold 104 has a molding surface 104 a that transfers the surface shape to the outer peripheral surface which is a non-optical functional surface of the glass molding material 201. The arithmetic average roughness Ra of the molding surface 104a of the auxiliary cylinder 104 is Ra ≦ 200 nm (more preferably Ra ≦ 60 nm).

  As described above, when the arithmetic average roughness Ra satisfies the above-described relationship, the occurrence of a change in the release state such as early or late release of the molding surface 104a of the auxiliary cylinder 104 and the glass molding material 201 is sufficiently generated. It has been empirically found that it can be suppressed. Thereby, it is possible to prevent cracks, cans, burn-in, and the like from occurring on the outer peripheral surface of the glass optical element 202. Furthermore, it is possible to suppress the occurrence of deviation of the release timing from the auxiliary body mold 104 for each part of the outer peripheral surface of the glass optical element 202, and as a result, the temperature changes for each part of the outer peripheral surface of the glass optical element 202. Generation of temperature distribution can be suppressed. Therefore, not only on the outer peripheral surface of the glass optical element 202 but also on the optical functional surface located inside the glass optical element 202, it is possible to prevent the variation in surface shape and the increase in the generation of asses, frames, and habits. be able to.

  Therefore, according to the present embodiment, the glass optical element 202 can be molded with high accuracy by stabilizing the release of the glass molding material 201 and the auxiliary body mold 104.

  In this embodiment, the distribution of the arithmetic average roughness Ra around the glass forming material 201 on the molding surface 104a of the auxiliary cylinder 104 is such that the difference ΔRa between the maximum value and the minimum value is ΔRa ≦ 50 nm (more Preferably ΔRa ≦ 30 nm). It has been empirically found that when the difference ΔRa satisfies such a relationship, the occurrence of a change in the release state can be more sufficiently suppressed around the glass forming material 201. Therefore, the glass optical element 202 can be molded with higher accuracy.

  In the present embodiment, the protective film 105 is formed on the molding surface 104 a of the auxiliary cylinder mold 104. Therefore, it is possible to prevent the deterioration of the auxiliary body mold 104 at a high temperature such as a heating process or a pressure molding process. As a result, it is possible to prevent the arithmetic average roughness Ra from increasing due to the deterioration of the molding surface 104a of the auxiliary body mold 104, and thus to prevent the release state from changing.

DESCRIPTION OF SYMBOLS 1 Glass optical element manufacturing apparatus 2 Molding chamber 2a Shielding plate 2b Input side shutter 2c Ejection side shutter 2d Internal shutter 10 Heating stage 20 Pressure molding stage 30 Cooling stage 11, 21, 31 Lower stage unit 12, 22, 32 Upper stage Unit 11a, 21a, 31a, 12a, 22a, 32a Temperature control block 11b, 21b, 31b, 12b, 22b, 32b Heat equalizing member 13, 23, 33 Pressurizing unit 40 Input side mounting table 50 Discharge side mounting table 100 Type set (Glass optical element molding mold set)
DESCRIPTION OF SYMBOLS 101 Upper mold | type 102 Lower mold | type 101a, 102a Molding surface 101b, 102b Stepped part 103 Cylinder mold 104 Auxiliary cylinder mold 104a Molding surface 201 Glass molding material 202 Glass optical element 301 Tool 301a Grinding stone 302 Tool 302a Contact part 303 Abrasive

Claims (4)

A first molding die and a second molding die, which are arranged so as to face each other with a glass molding material interposed therebetween, and have a molding surface for transferring a surface shape to the optical functional surface of the glass molding material;
A third mold having a molding surface disposed between the first mold and the second mold and transferring a surface shape to an outer peripheral surface which is a non-optical functional surface of the glass molding material; With
The arithmetic mean roughness Ra of the molding surface of the third mold is
Ra ≦ 200nm
A mold set for molding a glass optical element. The distribution of the arithmetic average roughness Ra around the glass molding material on the molding surface of the third mold is such that the difference ΔRa between the maximum value and the minimum value is
ΔRa ≦ 50nm
The mold set for molding a glass optical element according to claim 1.   The glass optical element molding die set according to claim 1, further comprising a protective film formed on the molding surface of the third molding die. A heating step of heating the glass molding material housed in the glass optical element molding die set;
A pressure molding step of pressure molding the heated glass molding material;
A cooling step of cooling the pressure-molded glass molding material,
The glass optical element molding die set is:
A first mold and a second mold that are arranged to face each other across the glass molding material and have a molding surface that transfers a surface shape to the optical functional surface of the glass molding material;
A third mold having a molding surface disposed between the first mold and the second mold and transferring a surface shape to an outer peripheral surface which is a non-optical functional surface of the glass molding material; With
The arithmetic mean roughness Ra of the molding surface of the third mold is
Ra ≦ 200nm
A method for producing a glass optical element.