WO2014034816A1 - Molding die manufacturing method, molding die, molding die regeneration method, and optical element manufacturing method - Google Patents

Abstract

The purpose of the present invention is to provide a molding die manufacturing method capable of fixing the position and height of optical transfer surfaces stably and with good precision even when the molding die is configured from peripheral molds and core molds. A method for manufacturing a molding die (40) provided with a fixed die (41), which is a first die, and a movable die (42), which is a second die. The method comprises: a member-manufacturing process for manufacturing the core molds (51, 61) and peripheral molds (52, 62) that configure the fixed die (41) and the movable die (42), the core molds having optical transfer surfaces (51a, 61a) for forming the optical surfaces (Sa, Sb) of a lens (OL), which is an optical element, and the peripheral molds being for supporting the core molds (51, 61) from the perimeter; and a unifying process for unifying the core molds (51, 61) with the peripheral molds (52, 62) via an oxidized section (OX) formed between the core molds (51, 61) and the peripheral molds (52, 62) by oxidizing the core molds (51, 61) when the core molds (51, 61) are inserted in the peripheral molds (52, 62).

Description

Method for manufacturing molding die, molding die, method for regenerating molding die, and method for manufacturing optical element

The present invention relates to a method for producing a molding die for molding an optical element, a molding die for an optical element, a method for regenerating the molding die, and a method for producing an optical element using the molding die.

There is a mold that combines an outer peripheral mold and a core mold as a mold for manufacturing an optical element. This mold is advantageous in that it is easy to process and does not take processing time. In particular, in the case of a mold for taking a large number of optical elements, for example, the processing time can be shortened, which is excellent in terms of processing speed and economy.

However, in the mold that combines the outer periphery mold and the core mold, the positional accuracy of the optical transfer surface and the stability of the height of the optical transfer surface are poor, and it is necessary to adjust the position of the core mold every time the mold is removed for maintenance etc. It becomes. In particular, in optical elements that require high-accuracy surface shapes, it is important to fix the position of the core mold in an accurate and stable state when it is necessary to position the core mold and the outer peripheral mold with high precision. It is.

Also, as a method for positioning the core mold, there is a method for positioning with respect to the cavity (mold space) using a difference in thermal expansion between the outer peripheral mold and the core mold at a high temperature (see Patent Document 1).

However, the method of Patent Document 1 has poor reproducibility when the core mold is detached and attached for maintenance or the like, and there is a possibility that the position adjustment of the core mold may be prolonged.

JP 11-90964 A

The present invention provides a manufacturing method of a molding die that can be fixed with the position and height of the optical transfer surface being accurately and stably even if the outer peripheral die and the core die are configured. Objective.

The present invention provides a molding die for an optical element that can accurately stabilize the position of the optical transfer surface and the like as described above, a method for regenerating the molding die, and manufacturing an optical element using the molding die. It aims to provide a method.

In order to solve the above problems, a manufacturing method of a molding die according to the present invention is a manufacturing method of a molding die for molding an optical element, which includes a first die and a second die. A member manufacturing step of manufacturing a core mold having an optical transfer surface that forms an optical surface of an optical element constituting at least one of the first and second molds, and an outer peripheral mold that supports the core mold from the periphery; In the state where the core mold is inserted into the outer peripheral mold, at least one of the core mold and the outer peripheral mold is oxidized, and an oxide portion made of an oxide is selectively formed between the core mold and the outer peripheral mold. And an integration step of integrating the core mold and the outer peripheral mold.

According to the above method for manufacturing a mold, unlike the case of manufacturing an integral mold by cutting a base material, the core mold and the outer peripheral mold can be individually processed. Fabrication can be facilitated. Further, since the core mold can be selected and incorporated into the outer peripheral mold, the yield of the molding dies can be improved. Moreover, after integrating the core mold and the outer peripheral mold by oxidation, it can be handled as a semi-permanent integrated mold. Thereby, adjustment of a metal mold | die can be abbreviate | omitted in the shaping | molding process which manufactures an optical element using the manufactured metal mold | die, and the manufacturing cost of an optical element can be reduced. That is, according to this manufacturing method, it is possible to manufacture a molding die having both the advantages of an integrated die and the advantages of a non-integrated die.

In a specific aspect or viewpoint of the present invention, the method for manufacturing a molding die includes a position adjusting step for adjusting the position of the core die with respect to the outer peripheral die before the integration step. In this case, when there are a plurality of core molds, the position of each core mold can be individually adjusted with respect to the outer peripheral mold.

In another aspect of the present invention, the position adjusting step is performed by supporting the core mold in the outer peripheral mold with the positioning member. In this case, before integrating the core mold and the outer peripheral mold, the core mold can be held or supported in a stable state with respect to the outer peripheral mold.

In still another aspect of the present invention, a positioning step of positioning the core mold with respect to the outer peripheral mold is provided after the position adjustment step and before the integration step. Here, the positioning means that the core mold is temporarily fixed to the outer peripheral mold. In this case, since the core mold is temporarily fixed after adjusting the position of the core mold, in the integration process of the next process, the adjusted core mold can be integrated without shifting.

In yet another aspect of the present invention, the positioning step is performed by thermally expanding the positioning member by heating. In this case, the core mold can be easily positioned with respect to the outer peripheral mold.

In yet another aspect of the present invention, the core mold and the outer peripheral mold have the same degree of thermal expansion, and the positioning member has a higher thermal expansion coefficient than that of the core mold. In this case, the positioning member having a higher coefficient of thermal expansion than the core mold or the outer peripheral mold can contact the outer peripheral mold prior to the core mold, thereby positioning the core mold.

In still another aspect of the present invention, the core mold is made of a first metal material, the positioning member is made of a second metal material different from the first metal material, and in the integration step, the core mold and the positioning member are Due to the difference in ionization tendency, the facing portion between the core mold and the positioning member is selectively oxidized. In this case, by oxidizing the boundary between the core mold and the positioning member away from the optical transfer surface, it is possible to prevent stress from being applied to the optical transfer surface and distortion on the optical transfer surface.

In still another aspect of the present invention, the method includes a coating process for forming an antioxidant film on at least the optical transfer surface of the core mold. In this case, it is possible to prevent the portion coated with the antioxidant film such as the optical transfer surface from being oxidized. Moreover, only a necessary part can be selectively oxidized.

A molding die according to the present invention is a molding die for an optical element including a first die and a second die, and at least one of the first and second die is A core mold having an optical transfer surface that forms an optical surface of the optical element, and an outer peripheral mold that supports the core mold from the periphery, and at least one of the core mold and the outer mold is oxidized to form the core mold and the outer mold. An oxide part is selectively formed between the core type and the outer peripheral type, and the core part and the outer peripheral type are integrated via the oxide part.

According to the above molding die, unlike the die that is integrated by cutting the base material, the core die and the outer peripheral die can be individually processed, so that the die can be manufactured. It becomes easy. Moreover, after integrating the core mold and the outer peripheral mold, they can be handled as an integrated mold. Thereby, adjustment of a metal mold | die can be shortened in the shaping | molding process which manufactures an optical element using the said shaping | molding metal mold | die, and the manufacturing cost of an optical element can be reduced.

In another aspect of the present invention, in the molding die, a portion other than the optical transfer surface of the core mold is selectively oxidized to form the oxidized portion.

In yet another aspect of the present invention, an antioxidant film is formed on at least the optical transfer surface of the core type.

In yet another aspect of the present invention, the core mold is supported by the positioning member, and the core mold and the outer peripheral mold have the same thermal expansion coefficient, and the positioning member is higher than the thermal expansion coefficient of the core mold.

In yet another aspect of the present invention, a plurality of core molds are inserted in one outer peripheral mold. In this case, a molding die in which the position and height of each core mold are precisely adjusted is obtained.

The method for regenerating a molding die according to the present invention includes a contact step of removing an oxidized portion by bringing an acid solution into contact with an oxidized portion of the molding die manufactured by the above-described manufacturing method of a molding die.

According to the method for regenerating the molding die, the core mold and the outer peripheral mold can be separated by dissolving the oxidized portion. Thereby, the core type | mold and outer periphery type | mold which have not deteriorated can be reused.

In another aspect of the present invention, in the above regeneration method, at least one of the core mold and the other outer peripheral mold is oxidized and selected in a state where the core mold from which the oxidized portion has been removed by the contact step is inserted into the other outer peripheral mold. And an integration step of forming an oxide portion made of oxide and integrating the core mold with another outer peripheral mold via the oxide portion.

In another aspect of the present invention, in the above regeneration method, at least one of the outer peripheral mold and the other core mold is oxidized and selected in a state where the other core mold is inserted into the outer peripheral mold from which the oxidized portion has been removed by the contact step. In particular, there is provided an integration step of forming an oxidized portion made of an oxide and integrating the outer peripheral mold and another core mold through the oxidized portion.

The method for producing an optical element according to the present invention produces an optical element using the above-described molding die.

According to the method for manufacturing an optical element, since the optical element is molded using a molding die in which the position and height of the optical transfer surface with respect to the outer peripheral mold are precisely adjusted, a highly accurate surface shape, surface layout, etc. The optical element which has can be manufactured. Further, the adjustment of the mold during the molding process can be shortened, and the manufacturing cost of the optical element can be reduced.

The method for manufacturing an optical element according to the present invention manufactures an optical element using a molding die regenerated by the above-described method for regenerating a molding die.

It is side sectional drawing of the shaping die of 1st Embodiment. It is a side view of the optical element shape | molded by the shaping die of FIG. FIG. 3A is a partially enlarged cross-sectional view of a fixed mold in the molding die of FIG. 1, and FIG. 3B is a side view of a core mold in the molding die. 4A to 4D are views for explaining a method of manufacturing the molding die shown in FIG. 5A to 5C are views for explaining a method of regenerating the molding die shown in FIG. It is a side view of the core type | mold of the shaping die of 2nd Embodiment.

[First Embodiment]
Hereinafter, the molding die etc. which are 1st Embodiment of this invention are demonstrated, referring drawings.

A) Molding Mold As shown in FIG. 1, the molding mold 40 of the present embodiment includes a fixed mold 41 that is a first mold and a movable mold 42 that is a second mold. Both molds 41 and 42 can be opened and closed with a parting line PL as a boundary. A mold space CV sandwiched between the fixed mold 41 and the movable mold 42 corresponds to the shape of a lens OL (see FIG. 2) as an optical element made of resin, for example. The lens OL shown in FIG. 2 includes an optical function part OP having an optical function located substantially at the center of the lens OL, and an annular flange part FL extending from the optical function part OP in the outer diameter direction.

The fixed mold 41 includes a core mold 51, an outer peripheral mold 52, and a positioning member 53. Here, the core mold 51 is disposed to face a core mold 61 of the movable mold 42 described later in order to form a mold space CV. The outer peripheral mold 52 is a mold member that holds or supports the core mold 51 from the periphery. In other words, the outer peripheral mold 52 includes a through hole into which the core mold 51 is inserted. The positioning member 53 is a member that positions the core die 51 from the back with respect to the outer peripheral die 52. As shown in an enlarged view in FIG. 3A, in this embodiment, the core mold 51 and the outer peripheral mold 52 are generated later as a result of the surface of the core mold 51 being oxidized. They are integrated through an oxide portion OX made of oxide.

A plurality of core molds 51 are provided for one outer peripheral mold 52. That is, the outer peripheral mold 52 includes a plurality of through holes, and the core mold 51 is inserted at a plurality of locations in one outer peripheral mold 52. At the tip of the core mold 51, an optical transfer surface 51a and a flange transfer surface 51b for defining a mold space CV are provided. The optical transfer surface 51a is, for example, a concave surface, and is a transfer surface that molds one optical surface Sa of the optical function unit OP constituting the lens OL shown in FIG. The flange transfer surface 51b is an annular flat surface, and is a transfer surface on which one flange surface Fa of the flange portion FL constituting the lens OL is molded. A recess 51 c for fitting with the positioning member 53 is provided on the back surface of the core mold 51, that is, on the positioning member 53 side. The diameter of the core mold 51 is, for example, 2.994 mm.

The core mold 51 is manufactured using WC (tungsten carbide), Ni, Cu, or an alloy thereof as a typical material. The thermal expansion coefficient of WC is 3.8 × 10 ⁻⁶ to 6 × 10 ⁻⁶ [K ⁻¹ ]. The thermal expansion coefficient of Ni is 13.4 × 10 ⁻⁶ [K ⁻¹ ], and the thermal expansion coefficient of Ni is 16.5 × 10 ⁻⁶ [K ⁻¹ ]. The material of the core mold 51 is not limited to the illustrated material, and any material that oxidizes and expands its volume may be used.

As shown in FIGS. 3A and 3B, the core mold 51 has a surface portion other than the optical transfer surface 51a selectively oxidized. Specifically, the oxidized portion OX is formed in a ring shape or a cylindrical shape near the contact portion VX that is a boundary between the core die 51 and the positioning member 53 on the side surface of the core die 51. The oxidized portion OX is an oxide of the material of the core mold 51, but is assumed to be different from the core mold 51 for convenience of explanation. The oxidation part OX fills the clearance ZE between the core mold 51 and the outer peripheral mold 52, so that the core mold 51 is fixed to the outer peripheral mold 52. The core mold 51 has an antioxidant film OM formed on at least one end of the optical transfer surface 51a so that the base surface to which the antioxidant film OM is applied is not oxidized. Specifically, the antioxidant film OM is coated on the side of the core mold 51 near the contact portion VX between the core mold 51 and the positioning member 53. That is, the member or material of the core mold 51 is exposed on the side surface of the core mold 51 near the contact portion VX. For the sake of explanation, in the drawing, the oxidized portion OX and the antioxidant film OM are exaggerated, but in actuality, they are thin films.

The outer peripheral mold 52 is formed with a through hole 52a having a cylindrical inner surface for inserting the core mold 51 and the positioning member 53. Moreover, the outer periphery type | mold 52 has the end surface 52b which forms the parting line PL. The hole diameter of the through hole 52a of the outer peripheral mold 52 is, for example, 3.000 mm. The distance (radial distance) between the core mold 51 and the outer peripheral mold 52 is preferably 1 to 7 μm on one side.

The outer peripheral mold 52 uses WC (tungsten carbide), Ni, Cu, or an alloy thereof as a typical material. The outer peripheral mold 52 has the same thermal expansion coefficient or core mold as the core mold 51 so that the positions of the outer peripheral mold 52 and the core mold 51 do not change between hot (when molding is used) and cold (at room temperature). A material having a thermal expansion coefficient equal to or lower than 51 is used.

Although not shown, the inner surface of the through hole 52a of the outer peripheral mold 52 is coated with an antioxidant film. Thereby, the oxidation of the through-hole 52a of the outer periphery mold | type 52 is prevented in the integration process mentioned later.

The positioning member 53 includes a lateral positioning member 53a and a height positioning member 53b in order to accurately determine the positions of the core mold 51 and the outer peripheral mold 52. The lateral positioning member 53a is a cylindrical shaft-shaped member that positions the lateral direction of the core mold 51 (the XY direction perpendicular to the axis AX or the Z direction in FIG. 1). On the tip of the positioning member 53a, that is, on the core mold 51 side, a protrusion 53c for fitting with the core mold 51 is provided. The positioning member 53b in the height direction is a columnar member that positions the core mold 51 in the height direction (the axis AX in FIG. 1 or the Z direction parallel to the Z direction). The positioning member 53 uses SUS (stainless steel) or the like as a typical material. In particular, the lateral positioning member 53 a uses a material having a higher coefficient of thermal expansion than the core mold 51 and the outer peripheral mold 52. For example, the thermal expansion coefficient of SUS410 is 10.4 × 10 ⁻⁶ [K ⁻¹ ], and the thermal expansion coefficient of SUS304 is 17.3 × 10 ⁻⁶ [K ⁻¹ ]. In this embodiment, for example, when the material of the core mold 51 and the outer peripheral mold 52 is WC and the material of the lateral positioning member 53a is SUS304, the thermal expansion of the core mold 51 and the outer peripheral mold 52 from the lateral positioning member 53a. A combination with a high rate. In addition, the material of the positioning member 53a in the horizontal direction and the positioning member 53b in the height direction may be the same or different.

Returning to FIG. 1, the movable mold 42 includes a core mold 61, an outer peripheral mold 62, and a positioning member 63. The movable mold 42 is movable along the axis AX and opens and closes with respect to the fixed mold 41. In the movable mold 42, the core mold 61 is disposed to face the core mold 51 of the fixed mold 41 in order to form a mold space CV. The outer peripheral mold 62 is a mold member that holds or supports the core mold 61 from the periphery. The positioning member 63 is a member that positions the core die 61 from the back with respect to the outer peripheral die 62. In the present embodiment, the core mold 61 and the outer peripheral mold 62 are integrated with each other by generating an oxidized portion when the core mold 61 is oxidized. The structures of the core mold 61, the outer periphery mold 62, and the positioning member 63 are substantially the same as the structures of the core mold 51, the outer periphery mold 52, and the positioning member 53 of the fixed mold 41, and will not be described below as appropriate.

Also in the movable mold 42, a plurality of core molds 61 are provided for one outer peripheral mold 62. At the tip of the core mold 61, an optical transfer surface 61a and a flange transfer surface 61b for defining a mold space CV are provided. The optical transfer surface 61a is a concave surface, and is a transfer surface that molds the other optical surface Sb of the optical function part OP constituting the lens OL shown in FIG. The flange transfer surface 61b is an annular flat surface, and is a transfer surface for forming the other flange surface Fb of the flange portion FL constituting the lens OL. A recess 61 c for fitting with the positioning member 63 is provided on the back surface of the core mold 61, that is, on the positioning member 63 side.

In the outer peripheral mold 62, a through hole 62a for inserting the core mold 61 and the positioning member 63 is formed. Moreover, the outer periphery type | mold 62 has the end surface 62b which forms the parting line PL.

The positioning member 63 includes a lateral positioning member 63a and a height positioning member 63b in order to accurately determine the positions of the core mold 61 and the outer peripheral mold 62. At the tip of the positioning member 63a, that is, on the core die 61 side, a convex portion 63c for fitting with the core die 61 is provided.

Although not shown, the molding die 40 is provided with a flow path for supplying resin to the mold space CV.

B) Manufacturing Method of Molding Mold Hereinafter, a manufacturing method of the molding die 40 shown in FIG. 1 will be described with reference to FIGS. 4A to 4D. Although the fixed mold 41 will be mainly described, the same applies to the movable mold 42. 4A to 4D, the intervals between the members 51, 52, and 53 are exaggerated for easy understanding. However, in reality, the gaps are minute.

[Member manufacturing process]
First, the core mold 51, the outer periphery mold 52, and the positioning member 53 are each produced. Each member 51, 52, 53 is produced by, for example, cutting. Here, for example, WC is used as the material of the core mold 51 and the outer peripheral mold 52. Further, SUS is used as the material of the positioning member 53.

[Coating process]
Next, an anti-oxidation film OM is coated on the portion of the core mold 51 that is not desired to be oxidized (for example, near the optical transfer surface 51a or the side surface of the core mold 51 unrelated to positioning) by using, for example, vacuum deposition (see FIG. (Refer FIG. 3A etc.). The inner surface of the through hole 52a of the outer peripheral mold 52 is also coated with an antioxidant film (not shown) using, for example, vacuum deposition. As a result, only necessary portions can be selectively oxidized.

[First position adjustment process]
Next, the core mold 51 and the lateral positioning member 53 a are combined and inserted into the outer peripheral mold 52. At this time, the position of the optical transfer surface 51a of the core mold 51 in the XY direction and the direction around the Z axis are adjusted. Specifically, the convex portion 53c of the lateral positioning member 53a is fitted into the concave portion 51c of the core mold 51, and the position of the positioning member 53a is adjusted. There are gaps of about 1 to 7 μm on one side between the core mold 51 and the outer peripheral mold 52 and between the lateral positioning member 53a and the outer peripheral mold 52, and the core mold 51 can be moved by moving the lateral positioning member 53a. The position in the XY direction with respect to the outer peripheral mold 52 can be adjusted. The final position of the core mold 51 with respect to the outer peripheral mold 52 is determined by a heat treatment in a positioning process described later.

[Second position adjustment step]
Next, the positioning member 53b in the height direction is inserted into the through hole 52a of the outer peripheral mold 52, and the bottom surface of the member 53a is brought into contact with the upper surface so that the height of the core mold 51 with respect to the outer peripheral mold 52 becomes a desired state. Adjust to. At this time, the height is determined in consideration of the difference in coefficient of thermal expansion between the outer peripheral mold 52 and the positioning members 53a and 53b. After the first and second position adjusting steps, as shown in FIG. 4A, the core mold 51 is supported in the outer peripheral mold 52 by the lateral positioning member 53a and the height positioning member 53b.

In the first and second position adjustment steps, a microscope, a laser displacement meter, or the like can be used as an indirect confirmation method of the position. In the case of a laser displacement meter, it can be easily observed even at high temperatures. Therefore, when a laser displacement meter is used, positioning can be performed while adjusting the position in the positioning step.

[Positioning process]
Next, in a state where the core mold 51 and the positioning member 53 are inserted into the outer peripheral mold 52, for example, heating is performed in air, that is, in an oxidizing atmosphere. Although the heating conditions differ depending on the material of each member 51, 52, 53, in the case of this embodiment, for example, heating is performed at 500 ° C. for 8 hours. Thereby, the volume of each member 51,52,53 expands. At this time, since the thermal expansion coefficient of the positioning member 53 is larger than that of the core mold 51, the side surface of the positioning member 53 comes into contact with the inner wall of the through hole 52a of the outer peripheral mold 52 as shown in FIG. 4B. On the other hand, the side surface of the core mold 51 and the inner wall of the through hole 52a of the outer peripheral mold 52 are not in contact. That is, the final position of the core mold 51 and the positioning member 53 is determined by the thermal expansion of the positioning member 53, and the center of the outer peripheral mold 52 and the center of the core mold 51 coincide. Further, the position of the core mold 51 in the direction of the optical axis AX is set to a correct position where the molded product has an intended thickness.

[Integration process]
Thereafter, oxidation proceeds at the contact portion VX between the WC member of the core mold 51 and the SUS member of the positioning member 53, which is a different metal, due to the difference in ionization tendency. There is a gap of about 3 μm on one side between the core mold 51 and the outer peripheral mold 52, and oxidation proceeds because oxygen enters from this gap. As a result, as shown in FIG. 4C, the WC member of the core mold 51 oxidizes and expands at the contact portion VX, and an oxidized portion OX is formed between the core mold 51 and the outer peripheral mold 52. The core mold 51 and the outer peripheral mold 52 are firmly fixed to each other through the oxidized portion OX to be integrated. The surfaces of the optical transfer surface 51a and the outer peripheral mold 52 are provided with an antioxidant film OM and are not oxidized by heat treatment. In addition, since the SUS member of the positioning member 53 and the WC member of the outer peripheral mold 52 are in close contact with each other under heating, the oxidation does not proceed. Even if there is a gap between the positioning member 53 and the outer peripheral mold 52, oxidation does not proceed because a passive layer of Cr oxide is formed on the SUS surface. After the heating, as shown in FIG. 4D, the volume of each member 51, 52, 53 contracts. Even if the volume of each member 51, 52, 53 shrinks, the core mold 51 and the outer peripheral mold 52 are in a semi-permanently fixed state via the oxidation part OX. The fact that the core mold 51 is fixed to the outer peripheral mold 52 is confirmed, for example, by applying the same load as at the time of molding, or by performing trial driving (molding). Thus, the fixed mold 41 in which the core mold 51 is fixed to the outer peripheral mold 52 in a state where the position of the core mold 51 is accurately adjusted is completed.

It should be noted that the positioning member 53 may be removed from the outer peripheral mold 52 once it has been oxidized and fixed.

C) Manufacturing Method of Optical Element Hereinafter, a manufacturing method of the lens OL using the molding die 40 shown in FIG. 1 will be described. Although not shown, the molding die 40 is used by being incorporated in an injection molding machine, and the fixed die 41 is fixed to a stationary platen of the injection molding machine, and a movable die 42 is used. Is fixed to the movable platen of the injection molding machine.

First, both molds 41 and 42 are heated to a temperature suitable for molding by a mold temperature controller (not shown). Next, the movable platen that supports the movable die 42 is brought close to the fixed platen that supports the fixed die 41, and is moved to the die contact position where the fixed die 41 and the movable die 42 are in contact with each other to close the die. At the same time, mold clamping is performed to clamp the fixed mold 41 and the movable mold 42 with a necessary pressure. Next, an injection device (not shown) is operated to inject the molten resin into the mold space CV between the fixed mold 41 and the movable mold 42 that are clamped at a necessary pressure. . At this time, the fixed mold 41 and the movable mold 42 are appropriately heated by the mold temperature controller, and the molten resin supplied from the injection apparatus is slowly cooled. When the molten resin is cooled and sufficiently cured, the fixed mold 41 and the movable mold 42 are separated from each other by performing mold opening for retracting the movable mold 42. As a result, the lens OL as an optical element can be taken out between the both molds 41 and 42.

If the injection molding as described above is repeated, the optical transfer surfaces 51a and 61a of the core dies 51 and 61 of both the dies 41 and 42 may be damaged or dust may not be used. There is. In this case, the core molds 51 and 61 and the outer peripheral molds 52 and 62 can be separated by the reproduction method described below, and new core molds 51 and 61 can be incorporated into the outer peripheral molds 52 and 62, for example.

D) Method of Regenerating Molding Mold Hereinafter, a method of regenerating the molding die 40 will be described with reference to FIGS. 5A to 5C. Although the fixed mold 41 will be mainly described, the same applies to the movable mold 42. In the reproduction method, the position adjusting step, the positioning step, and the integration step, which will be described later, are the same as the above-described manufacturing method of the molding die, and thus detailed description thereof is omitted.

[Preliminary process]
First, as shown in FIG. 5A, the positioning member 53 is removed from the fixed mold 41. Note that this step may be omitted.

[Immersion process]
Next, as shown in FIG. 5B, the core mold 51 and the outer periphery mold 52 are immersed in a solution of an acid or the like (for example, hydrochloric acid or an acid containing hydrochloric acid). By this dipping process (an example of a contact process), as shown in FIG. 5C, the oxidized portion (oxidized portion OX) is removed. Thereafter, the core mold 51 and the outer peripheral mold 52 are separated. When the positioning member 53 remains in the fixed mold 41, the positioning member 53 is also separated. The state of the separated core mold 51 and outer peripheral mold 52 is confirmed, and a reusable member is selected. Thereby, the separated core mold 51 and outer peripheral mold 52 can be selectively replaced with new ones. For example, by reusing the outer peripheral mold 52 even if the core mold 51 deteriorates, or by reusing the other core mold 51 and the outer peripheral mold 52 even if only some of the core molds 51 deteriorate. Furthermore, even if only the outer peripheral mold 52 is deteriorated, the core mold 51 is reused, thereby reducing the manufacturing cost of the molding die 40. That is, by removing the oxidation part OX, the core mold 51 and the outer peripheral mold 52 are separated, and a usable mold part is regenerated. Instead of immersing the mold in an acid solution or the like, it may be brought into contact with at least the oxidation part OX by spraying an acid solution (another type contact process). In this case, the oxidized portion OX can be easily removed even if the mold size is large.

[First position adjustment process]
When the outer peripheral mold 52 is reused, the new core mold 51 and the lateral positioning member 53 a are combined and inserted into the outer peripheral mold 52. The position of the optical transfer surface 51a of the core mold 51 in the X and Y directions is adjusted.

[Second position adjustment step]
Next, a positioning member 53b in the height direction is inserted into the through hole 52a of the outer peripheral mold 52, and the height of the core mold 51 with respect to the outer peripheral mold 52 is adjusted to a desired state (see FIG. 4A).

[Positioning process]
Next, the core mold 51 and the positioning member 53 are heated in the air while being inserted into the outer peripheral mold 52. As the positioning member 53 thermally expands, the center of the outer peripheral mold 52 and the center of the core mold 51 coincide (see FIG. 4B).

[Integration process]
Thereafter, oxidation proceeds at the contact portion VX between the WC member of the core mold 51 and the SUS member of the positioning member 53, which is a different metal, due to the difference in ionization tendency. As a result, the WC member of the core mold 51 of the contact portion VX oxidizes and expands, and an oxidized portion OX is formed between the core mold 51 and the outer peripheral mold 52 (see FIG. 4C). The core mold 51 and the outer peripheral mold 52 are integrated through the oxidation part OX (see FIG. 4D).

According to the molding die and the like described above, the core molds 51 and 61 and the outer peripheral molds 52 and 62 can be individually processed by cutting the base material, unlike the integral mold. The mold can be easily manufactured. Moreover, since the core molds 51 and 61 can be selected and incorporated into the outer peripheral molds 52 and 62, the yield of the molding dies 40 can be improved. Further, after the core molds 51 and 61 and the outer peripheral molds 52 and 62 are integrated by oxidation, they can be handled as a semi-permanently integrated mold. Thereby, adjustment of a metal mold | die can be shortened in the shaping | molding process which manufactures lens OL which is an optical element using the said metal mold 40, and the manufacturing cost of lens OL can be lowered | hung. That is, the molding die 40 of the present embodiment is a die having both the advantages of an integrated die and the advantages of a non-integrated die.

In particular, a lens used in a compound-eye optical system of a compound-eye imaging device that forms a plurality of images on an image sensor using a plurality of lenses arranged two-dimensionally and reconstructs one image from the obtained plurality of images. When molding an optical element having a plurality of optical surfaces such as an array, it is necessary to suppress variations in the shape of the optical surfaces in the array. According to the molding die 40 of this embodiment, since the molding die 40 can be assembled after the core dies 51 and 61 are selected, the yield of the molding die 40 can be improved.

Moreover, the molding die 40 of this embodiment can separate the core molds 51 and 61 and the outer peripheral molds 52 and 62 by melting the oxidized portion. Thereby, the core type | molds 51 and 61 and the outer periphery type | molds 52 and 62 which have not deteriorated can be reused.

[Second Embodiment]
Hereinafter, a molding die and the like according to the second embodiment will be described. The molding die and the like of the second embodiment is a modification of the molding die and the like of the first embodiment, and the parts that are not particularly described are the same as those of the first embodiment.

As shown in FIG. 6, the core mold 51 is coated with an antioxidant film OM so that two members of the core mold 51 are exposed. Thereby, the oxidation part OX is formed in two places in the shape of a ring zone in the vicinity of the contact part VX (see FIG. 3A) that is the boundary between the core mold 51 of the core mold 51 and the positioning member 53. By providing two oxidation parts OX in the core mold 51, the core mold 51 can be fixed in a stable state by the outer peripheral mold 52.

As mentioned above, although the molding die etc. which concern on this embodiment were demonstrated, the molding die etc. which concern on this invention are not restricted to said thing. For example, in the above-described embodiment, the shape, size, number, arrangement interval, and the like of the optical transfer surfaces 51a and 61a and the like can be appropriately changed according to the application and function.

In the above embodiment, the core dies 51 and 61 and the positioning member 53 are fitted, but the core dies 51 and 61 and the positioning member 53 may be welded.

Further, in the above embodiment, the pattern and range of the antioxidant film OM applied to the core molds 51 and 61 are examples, and can be changed as appropriate.

In the above embodiment, the core molds 51 and 61 are oxidized, but the outer peripheral molds 52 and 62 may be oxidized. In this case, the entire core mold 51, 61 is coated with the antioxidant film OM. Further, an antioxidant film is coated on the through holes 52a and 62a of the outer peripheral molds 52 and 62 other than the portions to be oxidized (portions away from the optical transfer surfaces 51a and 61a). Note that only the necessary portions of both the core molds 51 and 61 and the outer peripheral molds 52 and 62 may be selectively oxidized.

In the above embodiment, a plurality of through holes are provided in one outer peripheral mold 52, 62 and a plurality of core molds 51, 61 are provided. The number of core molds 51, 61 depends on the use and function of the molded product. It can be changed as appropriate. For example, one or more core molds 51 and 61 may be provided in one outer peripheral mold 52 and 62.

In the above embodiment, the core molds 51 and 61 are fixed to the outer peripheral molds 52 and 62 through the oxidation part OX in both the fixed mold 41 and the movable mold 42. Only one of 42 may be fixed by the above method. For example, if only the core mold 51 of the fixed mold 41 is fixed by the above method, the core mold 61 of the movable mold 42 can be used as a protruding mechanism.

In the above embodiment, the molding die 40 is an injection molding die, but it may be a pressing die for molding a glass molded product.

Claims (18)

1. A method for producing a molding die for molding an optical element comprising a first die and a second die,
   A core mold having an optical transfer surface for forming an optical surface of an optical element constituting at least one of the first and second molds and an outer peripheral mold for supporting the core mold from the periphery are produced. Member production process;
   With the core mold inserted into the outer peripheral mold, at least one of the core mold and the outer peripheral mold is oxidized, and an oxide portion made of an oxide is selectively formed between the core mold and the outer peripheral mold. A method for producing a molding die, comprising: an integration step of integrating the core mold and the outer peripheral mold through the oxidation portion.
2. The method for manufacturing a molding die according to claim 1, further comprising a position adjusting step of adjusting a position of the core die with respect to the outer peripheral die before the integrating step.
3. The method for manufacturing a molding die according to claim 2, wherein the position adjusting step is performed by supporting the core die in the outer peripheral die with a positioning member.
4. The method for manufacturing a molding die according to any one of claims 2 and 3, further comprising a positioning step of positioning the core die with respect to the outer peripheral die before the integration step after the position adjusting step.
5. The method for manufacturing a molding die according to claim 4, wherein the positioning step is performed by thermally expanding the positioning member.
6. The molding die according to claim 5, wherein the core mold and the outer peripheral mold have substantially the same coefficient of thermal expansion, and the positioning member has a coefficient of thermal expansion higher than that of the core mold. Production method.
7. The core mold is made of a first metal material, the positioning member is made of a second metal material different from the first metal material, and the ionization tendency between the core mold and the positioning member in the integration step. The manufacturing method of the molding die as described in any one of Claim 3-6 which oxidizes the opposing site | part of the said core type | mold and the said positioning member by the difference of these.
8. The method for producing a molding die according to any one of claims 1 to 7, further comprising a coating step of forming an antioxidant film on at least the optical transfer surface of the core mold.
9. A molding die for an optical element comprising a first die and a second die,
   At least one of the first and second molds includes a core mold having an optical transfer surface that forms an optical surface of an optical element, and an outer peripheral mold that supports the core mold from the periphery.
   At least one of the core mold and the outer peripheral mold is oxidized to selectively form an oxidized portion between the core mold and the outer peripheral mold, and the core mold and the outer peripheral mold are integrated via the oxidized portion. Molding mold that has become.
10. The molding die according to claim 9, wherein a portion of the core mold other than the optical transfer surface is selectively oxidized to form the oxidized portion.
11. The molding die according to any one of claims 9 and 10, wherein an antioxidant film is formed on at least the optical transfer surface of the core mold.
12. The core mold is supported by a positioning member,
    The molding according to any one of claims 9 to 11, wherein the core mold and the outer peripheral mold have substantially the same coefficient of thermal expansion, and the positioning member is higher than the coefficient of thermal expansion of the core mold. Mold.
13. The molding die according to any one of claims 9 to 12, wherein a plurality of the core dies are inserted in one outer peripheral die.
14. A contact step of removing the oxidized portion by bringing an acid solution into contact with the oxidized portion of the molding die manufactured by the method for manufacturing a molded die according to any one of claims 1 to 8, A method for reclaiming molds.
15. In the state where the core mold from which the oxidized portion has been removed by the contacting step is inserted into another outer peripheral mold, at least one of the core mold and the other outer peripheral mold is oxidized, and an oxidized portion made of an oxide selectively. The molding die regeneration method according to claim 14, further comprising an integration step of forming the core mold and the other outer peripheral mold through the oxidation portion.
16. In a state where another core mold is inserted into the outer peripheral mold from which the oxidized portion has been removed by the contact step, at least one of the outer peripheral mold and the other core mold is oxidized, and an oxidized portion made of an oxide is selectively formed. The molding die regeneration method according to claim 14, further comprising an integration step of forming and integrating the outer peripheral mold and the other core mold through the oxidation portion.
17. A method for manufacturing an optical element, wherein the optical element is manufactured using the molding die according to any one of claims 9 to 13.
18. A method for manufacturing an optical element, wherein an optical element is manufactured using the molding die regenerated by the method for regenerating a molding die according to any one of claims 15 and 16.

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