JP2019001683A - Mold releasing film, optical element forming mold, method for manufacturing optical element forming mold and method for manufacturing optical element - Google Patents

Abstract

[Problem] To provide a mold release film whose release performance is unlikely to deteriorate even when subjected to repeated high-temperature molding. [Solution] A mold release film (4) is provided with a film body (2) made of a metal or alloy containing a precious metal element that does not melt at the molding temperature, and a mold release agent (3) dispersed within the film body (2) in a state that allows it to move to the surface (2a) of the film body (2) that comes into contact with the molding material at the molding temperature. [Selected Figure] Figure 2

Description

  The present invention relates to a release film, an optical element molding die, a method for manufacturing an optical element molding die, and a method for manufacturing an optical element.

There is known an optical element manufacturing method in which a glass material for molding is heated to a molding temperature equal to or higher than a softening point and is pressed by an optical element molding die.
Since the glass material heated to a high temperature is easily fused with the optical element molding die, a release film is often formed on the molding surface of the optical element molding die. However, since the release film deteriorates with time when molding is repeated, it is necessary to periodically re-form the release film.
In order to extend the life of the release film, it is also known that a release agent is interposed between the molding surface and the glass material. An organic compound is used as the release agent.
For example, Patent Document 1 describes a glass molding method in which an organic compound that is thermally decomposed to form a carbon thin film upon heating and softening of a glass material is applied to the glass material before heating.

JP-A-11-116253

However, since conventional mold release agents are consumed by decomposition or volatilization in a single molding, the mold release agent is applied to the molding surface of the molding material or optical element molding die each time molding is performed. Need to be done. For example, since the mold release agent described in Patent Document 1 is an organic compound that decomposes at the time of molding to form carbon, all the applied mold release agents are decomposed by a single molding. For this reason, there exists a problem that manufacturing efficiency falls by the application | coating operation | work of the mold release agent performed for every shaping | molding.
Furthermore, a mold release agent composed of an organic compound may cause a product of thermal decomposition to remain on the surface of the molded body. In this case, depending on the characteristics of the residue, the residue may cause a spider on the surface of the molded body.

  The present invention has been made in view of the above problems, and a release film, an optical element molding die, and a method for manufacturing an optical element molding mold, in which the mold release performance is unlikely to deteriorate even when high temperature molding is repeated. And an optical element manufacturing method.

  In order to solve the above problems, a release film according to the first aspect of the present invention is made of a metal or an alloy containing a noble metal element, the film body does not melt at a molding temperature, and the film at the molding temperature. And a release agent dispersed inside the film body in a state of being movable to the surface in contact with the molding material in the body.

In the release film, the release agent may be dispersed in a range less than the thickness of the film body from the surface.
In the release film, the melting point of the release agent may be lower than the molding temperature.
In the release film, the release agent may be an inorganic material.
In the release film, the film body may have a nanoporous structure in a range in which the release agent is dispersed.

  An optical element molding die according to the second aspect of the present invention includes the release film.

  According to a third aspect of the present invention, there is provided a method for manufacturing an optical element molding die, comprising: preparing a base material that forms at least a part of a molding die body and having a molding surface formed thereon; Forming a base film having a film body material made of a metal or an alloy containing a noble metal element, and a removal material dispersed in the film body material; and at least part of the removal material from the base film And removing to form a void communicating with the surface of the base film from the inside of the base film, and introducing a release agent into the void.

  According to a fourth aspect of the present invention, there is provided a method for manufacturing an optical element molding die, comprising at least a part of a molding die body and preparing a base material on which a molding surface is formed; Forming a base film made of a metal or alloy containing a noble metal element, a film body material made of a metal or alloy containing a noble metal element on the surface of the base film, and a removal material dispersed in the film body material; And forming a void portion communicating from the inside of the base film to the surface of the base film by removing at least a part of the removal material from the base film. And introducing a release agent into the gap.

  According to a fifth aspect of the present invention, there is provided a method for manufacturing an optical element molding die, comprising: preparing a base material that forms at least a part of a molding die body and having a molding surface; Forming a base film having a metal or alloy containing a noble metal element, and a nanoporous structure having a minute opening on the surface of the base film, and a void extending from the opening to the inside of the base film. Forming on the base film, and introducing a release agent into the gap.

  According to a sixth aspect of the present invention, there is provided a method for manufacturing an optical element, comprising: molding an optical element by molding the molding material using an optical element molding die provided with the release film; and After a plurality of molds are formed, replenishing the mold release agent inside the mold release film is repeated.

  According to the release film, the optical element molding die, the optical element molding die manufacturing method, and the optical element manufacturing method of the present invention, the mold release performance is unlikely to deteriorate even when high temperature molding is repeated.

It is a typical longitudinal cross-sectional view which shows an example of the optical element shaping | molding die of the 1st Embodiment of this invention. It is typical sectional drawing which shows the structure of the release film of the 1st Embodiment of this invention. It is a typical A view enlarged view in the B section in FIG. It is CC sectional drawing in FIG. It is process explanatory drawing of the manufacturing method of the optical element shaping | molding die of the 1st Embodiment of this invention. It is process explanatory drawing of the manufacturing method of the optical element shaping | molding die of the 1st Embodiment of this invention. It is process explanatory drawing of the manufacturing method of the optical element shaping | molding die of the 1st Embodiment of this invention. It is a typical E view enlarged view in the F section in FIG. It is HH sectional drawing in FIG. It is process explanatory drawing of the manufacturing method of the optical element shaping | molding die of the 1st Embodiment of this invention. It is process explanatory drawing of the manufacturing method of the optical element shaping | molding die of the 2nd Embodiment of this invention. It is process explanatory drawing of the manufacturing method of the optical element shaping | molding die of the 2nd Embodiment of this invention. It is process explanatory drawing of the manufacturing method of the optical element shaping | molding die of the 2nd Embodiment of this invention. It is typical sectional drawing which shows the structure of the release film of the 3rd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
A release film and an optical element molding die according to a first embodiment of the present invention will be described.
FIG. 1 is a schematic longitudinal sectional view showing an example of an optical element molding die according to the first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing the configuration of the release film according to the first embodiment of the present invention. FIG. 3 is a schematic A view enlarged view of a portion B in FIG. 4 is a cross-sectional view taken along the line CC in FIG. Since each drawing is a schematic diagram, dimensions and shapes are exaggerated (the same applies to other drawings).

As shown in FIG. 1, the molding die assembly 10 includes a lower mold 10A (optical element molding mold), an upper mold 10B (optical element molding mold), and a body mold 10C. The lower mold 10A, the upper mold 10B, and the trunk mold 10C are arranged in a positional relationship in which the central axes of the lower mold 10A, the upper mold 10B, and the trunk mold 10C are coaxial with each other.
The molding die assembly 10 is used to mold an optical element using the molding material G.
The molding material G is made of an appropriate glass material for constituting the optical element. The molding material G is molded into an appropriate lump shape. In FIG. 1, as an example, the shape of the molding material G is spherical. However, the shape of the molding material G is not limited to a spherical shape as long as it can be press-molded by the molding die assembly 10. In addition to the spherical shape, the molding material G may be, for example, a disk shape, a spheroid shape, or a shape similar to an optical element.
The molding means for the molding material G may be molding, or may be machining such as cutting and polishing.
The type and shape of the optical element molded by the molding die assembly 10 are not limited. For example, examples of the optical element include a lens, a mirror, a prism, and a parallel plate. FIG. 1 shows, as an example, a mold assembly 10 for use in molding a flanged biconvex lens.

The lower mold 10A is formed of a substantially columnar member having a cylindrical side surface 10c. In the lower mold 10A, a mold surface 10a is formed at a first end portion in the axial direction (the upper end portion in FIG. 1).
The mold surface 10a transfers the surface shape of the optical element to the molding material G. For example, when the optical element is a biconvex lens with a flange, the shape of the mold surface 10a may be configured by a combination of a concave surface that forms a convex lens surface and a plane that forms a flange surface.
A flange portion 10d is formed at a second end portion opposite to the first end portion in the axial direction of the lower mold 10A. The flange portion 10d extends radially outward from the side surface 10c of the lower mold 10A.

As shown in FIG. 2, the mold surface 10 a is constituted by a release film 4. The release film 4 is formed on the molding surface 1a formed on the substrate 1A.
The base material 1A is made of, for example, a material having high hardness and good heat resistance, such as a cemented carbide mainly composed of tungsten carbide (WC), silicon carbide, or carbon. The base material 1 </ b> A may constitute the entire lower mold 10 </ b> A excluding the release film 4. The base material 1A may be disposed only at the first end of the lower mold 10A. The entire lower mold 10A excluding the release film 4 constitutes a mold body. For this reason, 1 A of base materials comprise at least one part of a shaping | molding die main body.
The molding surface 1a has a shape that approximates the surface of the optical element to be molded. The molding surface 1a is mirror-polished. For example, the surface accuracy of the molding surface 1a may be 0.15 μm or less in terms of PV value. For example, the surface roughness of the molding surface 1a may be 3 nm or less in terms of arithmetic average roughness Ra.

The release film 4 includes a film body 2 and a release agent 3.
The film body 2 is made of a metal or alloy containing a noble metal element and not melted at the molding temperature. As the composition of the film body 2, an appropriate composition that does not easily cause fusion with the molding material G is used. Examples of noble metal elements contained in the film body 2 include platinum (Pt), gold (Au), iridium (Ir), osmium (Os), rhodium (Rh), ruthenium (Ru), and palladium (Pd). It is done. As the film body 2, one kind of noble metal alone or an alloy of two or more kinds of noble metals may be used. Noble metal elements are less likely to cause a chemical reaction during molding with glass components at the molding temperature of the glass material. For this reason, the mold release property with respect to the shape | molded glass material becomes favorable.
For example, one or more metals other than noble metals such as rhenium (Re), tantalum (Ta), and molybdenum (Mo) may be added to the film body 2.
Elements other than the noble metals added to the film body 2 may include elements that can be removed from the film body 2 in order to form the voids 5 described later. For example, since Re and Mo sublimate when they become oxides, they can be removed from the film body 2 even after being contained in the film body 2.

The membrane body 2 includes a membrane body base layer portion 2A and a membrane body upper layer portion 2B in this order from the molding surface 1a side.
The membrane body base layer portion 2 </ b> A is a dense layered portion made of the material of the membrane body 2. The surface of the membrane body base layer 2A that is in close contact with the molding surface 1a constitutes the bottom surface 2b of the membrane body 2.
The membrane body upper layer portion 2B is formed so as to overlap the membrane body base layer portion 2A. The surface opposite to the membrane body base layer portion 2 </ b> A constitutes a surface 2 a of the membrane body 2. The surface 2a is the outermost surface of the film body 2 that contacts the molding material G during molding.

As shown in FIG. 4, the membrane body upper layer portion 2 </ b> B has a large number of void portions 5. The gap portion 5 is used to accommodate a release agent 3 described later in a movable manner. After the gap 5 is formed at the time of manufacturing the membrane body 2, a release agent 3 described later is introduced into the gap 5. Each void 5 in the unused release film 4 is filled with a release agent 3. 3 and 4 schematically illustrate an example of such an unused release film 4. As will be described later, the shape of the inner peripheral surface of the gap 5 does not change even if the release agent 3 moves to the outside of the gap 5 during molding of the optical element.
Below, also when explaining the space | gap part 5 with reference to FIG. 3, 4, it may be demonstrated on the assumption that the mold release agent 3 is not introduced as needed.

The gap 5 is formed so as to open on the surface 2a. For this reason, as shown in FIG. 3, the opening part 2c by each space | gap part 5 is opening in the surface 2a. In FIG. 3, all of the openings 2 c are drawn in a circle for simplification of illustration. However, the shape of the opening 2c is not limited to a circle. For example, the opening 2c may be formed in an elliptical shape, a polygonal shape, a long hole shape, or the like.
As shown in FIG. 4, the gap 5 extends downward from the opening 2c toward the membrane main body base layer 2A (not shown). Each gap 5 may merge with another gap 5 or may penetrate another gap 5. Each gap 5 may be branched into a plurality toward the membrane body base layer 2A (not shown).

The length of each gap portion 5 in the layer thickness direction of the membrane body upper layer portion 2B need not be a constant value. Of the end portions of the gap portion 5, a group of end portions extending closer to the bottom surface 2b and a virtual envelope surface that smoothly touches as a whole is a boundary surface BS (between the membrane body upper layer portion 2B and the membrane body base layer portion 2A). (See FIG. 2).
As shown in FIG. 2, in the film thickness direction of the film body 2, the distance from the surface 2a to the boundary surface BS defines the layer thickness t2 of the film body upper layer portion 2B. The layer thickness t2 may change at each position viewed from the film thickness direction, but in the present embodiment, the layer thickness t2 is substantially constant.
Assuming that the film thickness from the bottom surface 2b to the surface 2a of the release film 4 is t1, the film body base layer portion 2A and the film body upper layer portion 2B have layer thicknesses t1 to t2 and t2 (where 0 <t2 <t1 ).
The layer thickness t1 can be 0.2 μm or more and 3.0 μm.
The layer thickness t1-t2 of the film main body base layer portion 2A is determined so that the film strength necessary for the release film 4 and the adhesion strength to the molding surface 1a become the required strength. For example, when t1 is 1.2 μm, the layer thickness t1-t2 may be 0.1 μm or more and 1.1 μm or less. The layer thickness t1-t2 is more preferably 0.2 μm or more and 0.6 μm or less.
The layer thickness t2 of the film body upper layer part 2B is determined according to the required amount of the release agent 3 filled in the gap part 5. For example, when t1 is 1.2 μm, the layer thickness t2 may be 0.1 μm or more and 1.1 μm or less. The layer thickness t2 is more preferably 0.6 μm or more and 1.0 μm or less.
The layer thickness t2 may be 1/2 or less of the layer thickness t1.

The membrane body upper layer portion 2B is a layered portion that is sparser than the membrane body base layer portion 2A when the release agent 3 is not filled. Each gap 5 may have the same shape as each other or may be regularly arranged. However, FIGS. 3 and 4 schematically show examples in which the shapes of the gaps 5 are different from each other and the arrangement is not regular.
The membrane body upper layer portion 2B may have a nanoporous structure that is a porous structure in which at least some of a large number of pores having a pore size of the order of nanometers communicate with each other.
The size of the cross section orthogonal to the extending direction of each void 5 is more preferably 1 nm or more and 20 nm or less. Here, the size of the cross section being 1 nm or more and 20 nm or less means that the minimum inner diameter and the maximum inner diameter in each cross section are 1 nm or more and 20 nm or less.
The inner diameter D of the opening 2c of each gap 5 on the surface 2a is more preferably 1 nm or more and 20 nm.

  The membrane body upper layer portion 2 </ b> B is made of a material used for the membrane body 2. The material of the membrane body upper layer 2B may have the same composition as the material of the membrane body base layer 2A or a composition different from the material of the membrane body base layer 2A as long as it contains a noble metal element on the surface 2a. You may have. When the membrane body upper layer portion 2B has a composition different from the material of the membrane body base layer portion 2A, the composition of the membrane body upper layer portion 2B may have some components removed or reduced in the composition of the membrane body base layer portion 2A. .

The release agent 3 is made of a material that is difficult to adhere to at least one of the molding material G and the film body 2 in order to suppress the fusion between the molding material G and the film body 2. The mold release agent 3 is made of a material that can be easily removed even if it adheres to the surface of the molded product after molding of the optical element, or that does not affect the optical performance of the optical element even if it remains attached.
The release agent 3 is dispersed inside the film body 2 in a state where it can move to the surface 2a at the molding temperature. Specifically, as shown in FIG. 4, the release agent 3 is introduced into the gap 5 of the membrane body upper layer 2B.
Here, the state in which the release agent 3 can move to the surface 2a at the molding temperature is not particularly limited as long as the release agent 3 can move by applying thermal energy corresponding to the molding temperature.
For example, the release agent 3 may be a substance that can move along the gap 5 and reach the surface 2a from the opening 2c by changing the phase to a liquid phase or a gas phase depending on the molding temperature. Good. In this case, as the release agent 3, an appropriate inorganic material or organic material having a melting point lower than the molding temperature may be used. However, an inorganic material is more preferable than an organic material in terms of good thermal stability.
For example, the release agent 3 is moved along the gap 5 as a result of chemical changes such as reduction, oxidation, and thermal decomposition caused by the application of thermal energy corresponding to the molding temperature, and the surface of the release agent 3 from the opening 2c. A substance that generates a substance that can reach 2a may be used.

  As the release agent 3, a substance capable of obtaining release performance may be selected depending on the difference in coefficient of thermal expansion between the film body 2 and the molding material G. When the thermal expansion coefficient of the mold release agent 3 is different from that of at least one of the film body 2 and the molding material G, the interface between the mold release agent 3 and the surface 2a depends on the difference in shrinkage rate during cooling after molding. Alternatively, a shear deviation in the surface direction occurs at the interface between the release agent 3 and the molding material G. For this reason, it becomes easy to release the molding material G from the release film 4.

  For example, examples of suitable materials for the release agent 3 include zinc, tin, antimony, antimony pentoxide, and the like.

As shown in FIG. 1, the upper mold | type 10B consists of a substantially columnar member provided with the cylindrical surface side 10e. The upper mold 10B has a mold surface 10b formed at a first end in the axial direction (end on the lower side in FIG. 1).
The mold surface 10b transfers the surface shape of the optical element to the glass material. For example, when the optical element is a biconvex lens with a flange, the shape of the mold surface 10b may be configured by a combination of a concave surface that forms a convex lens surface and a plane that forms a flange surface.
A flange portion 10f is formed at the second end portion opposite to the first end portion in the axial direction of the upper mold 10B. The flange portion 10f extends radially outward from the side surface 10e of the upper mold 10B.

As shown in FIG. 2, the mold surface 10b is constituted by a release film 4 similar to the mold surface 10a. The release film 4 on the mold surface 10b is formed on the molding surface 1b formed on the substrate 1B. The base 1B is made of the same material as the base 1A.
As with the base material 1A, the base material 1B may constitute the entire upper mold 10B excluding the release film 4. The base material 1B may be disposed only at the first end of the upper mold 10B. The entire upper mold 10B excluding the release film 4 constitutes a mold body. For this reason, the base material 1B constitutes at least a part of the mold body.
The molding surface 1b has a shape that approximates the surface of the optical element to be molded. The molding surface 1b is mirror-polished. The surface accuracy and surface roughness of the molding surface 1b are the same as those of the molding surface 1a.

As shown in FIG. 1, the body mold 10C is a cylindrical member having an inner peripheral surface 10g that slidably fits the side surface 10c of the lower mold 10A and the side surface 10e of the upper mold 10B.
The axial length of the body mold 10C is shorter than the distance between the flange portions 10d and 10f in the assembled state of the molding die assembly 10 described later.
With such a configuration, the body mold 10C can hold the lower mold 10A and the upper mold 10B in a coaxial positional relationship during molding and can guide the upper mold 10B to be movable in the axial direction.
The body mold 10C may be made of an appropriate metal material or ceramic having heat resistance against the molding temperature. As an example of the material of the copper mold 10C in the present embodiment, a cemented carbide having high hardness and good heat resistance is used.

  The molding die assembly 10 is assembled in a state in which the first ends of the lower die 10A and the upper die 10B are inserted into the body die 10C. Between the mold surfaces 10a and 10b, a molding material G weighed to a mass necessary for molding is arranged.

A method for manufacturing the optical element molding die of this embodiment will be described.
5, 6, and 7 are process explanatory views of the method for manufacturing the optical element molding die according to the first embodiment of the present invention. FIG. 8 is a schematic enlarged view of E in the F part in FIG. 9 is a cross-sectional view taken along line HH in FIG. FIG. 10 is a process explanatory diagram of the method for manufacturing the optical element molding die according to the first embodiment of the present invention.

  As described above, the lower mold 10A and the upper mold 10B differ only in the shapes of the molding surfaces 1a and 1b. Therefore, in the following, the method for manufacturing the optical element molding die of the present embodiment will be described by taking the lower die 10A as an example. For simplicity, the substrate 1A will be described as being formed in the shape of the mold body.

In order to manufacture the lower mold 10A, in this embodiment, as shown in FIG. 5, a base material 1A on which a molding surface 1a is formed is prepared. However, FIG. 5 is a schematic cross-sectional view in which a part of the substrate 1A is enlarged (hereinafter, the same applies to FIGS. 6 to 10).
When the optical element to be manufactured is determined by the lower mold 10A, the outer shape of the optical element and the molding material G used for molding are specified. The molding material G is molded into the shape of the optical element at a molding temperature higher than the yield point of the molding material G.
A material that can withstand the molding temperature is selected as the material used for the substrate 1A. The material used for the substrate 1A is formed into a shape such as a shape in which a flange portion 10d protrudes from an end of a cylinder having a side surface 10c. Thereafter, a molding surface 1a is formed at the end of the cylinder opposite to the flange portion 10d. In the finishing process of the molding surface 1a, mirror polishing is performed.
Thus, the base material 1A on which the molding surface 1a is formed is prepared.

Thereafter, a release film 4 is formed on the molding surface 1a. In the present embodiment, the mold release film 4 is formed by forming a base film, forming the gap 5 in the base film, and introducing the release agent 3 into the gap 5. , Is included.
As shown in FIG. 6, first, the base film 20 is formed on the molding surface 1a.
In the present embodiment, the base film 20 near the molding surface 1a constitutes the film body base layer 2A (see FIG. 2). A film body upper layer 2B (see FIG. 2) is formed on the base film 20 near the surface 20a opposite to the molding surface 1a. For this reason, the material of the base film 20 includes at least the same material as the membrane main body base layer 2A near the molding surface 1a and the same material as the membrane main body upper layer 2B near the surface 20a.
Specifically, the base film 20 includes a film body material that is commonly included in the film body base layer 2A and the film body upper layer 2B, and a removal material that can be removed from the film body upper layer 2B. Here, being removable from the film body upper layer portion 2B means that the removal material itself may be removable, or the removal material may be removed by thermal decomposition or chemical change. Also good.

The removal material is dispersed at least in the region where the film body upper layer 2B is formed. The removal material may be uniformly distributed in the film thickness direction in the base film 20 or may be unevenly distributed in a region where the film body upper layer portion 2B is formed. When the removal material is distributed in the region to be the membrane body base layer portion 2A, a material having a melting point higher than the molding temperature and stable inside the membrane body material at the molding temperature is used as the removal material.
The removal material is removed from at least the region where the film body upper layer 2B is formed in order to form the void 5. For this reason, the removal material may not be a material that improves the releasability of the molding material G.

The distribution of the removal material in the base film 20 is more preferably a distribution corresponding to the gap 5 to be formed. However, the distribution of the removal material may be a distribution in which the shape of the void portion 5 described later is obtained by the removal material moving from the initial distribution state in the removal material removal process described later.
For example, when the removal material is distributed in a minute unit in the base film 20, the movement and aggregation of the base film 20 are repeated in the removal process, which will be described later. A shape may be formed.
For example, in the base film 20, when the removal material is vaporized and escapes to the outside of the base film 20, the surrounding film main body material is blown away or deformed, whereby the void portion 5 having a shape different from the initial distribution state is obtained. The shape may be formed.

  For example, materials suitable for the removal material include rhenium, molybdenum, silver, manganese, cobalt, polyvinyl pyrrolidone, and polyvinyl alcohol.

As a film forming method, an appropriate film forming method is selected according to the material of the base film 20. For example, examples of a film forming method for forming the base film 20 on the molding surface 1a include vapor deposition, RF sputtering, DC sputtering, magnetron sputtering, ion beam sputtering, ion plating, ion mixing, and the like.
When a film forming method is used in which the unevenness of the surface 20a of the base film 20 is within the allowable range as the mold surface without requiring a finishing process such as mirror polishing, the film thickness t3 of the base film 20 is the film body 2. The film thickness is the same as the film thickness t1.
Since the unevenness of the surface 20a of the base film 20 falls within the allowable range as the mold surface, the film thickness t3 of the base film 20 is the thickness of the film body 2 when a finishing process such as mirror polishing is necessary after film formation. The thickness is obtained by adding the finishing allowance to the film thickness t1.

After the base film 20 is formed, the gap 5 is formed in the base film 20.
In the present embodiment, as schematically shown in FIG. 7, the removal material in the base film 20 is removed from the region that becomes the film body upper layer portion 2 </ b> B, whereby the void portion 5 is formed.
As a method for removing the removal material, for example, a removal method in which the removal material is converted into a substance that easily volatilizes by a chemical reaction such as oxidation and then heated may be performed. For example, a removal method may be performed in which the removal material is converted into a substance that is easily melted by a chemical reaction such as oxidation and then heated.
According to such a removal material removal method, the removal material in the base film 20 is sequentially removed from the portion exposed on the surface 20a. Therefore, as shown in FIGS. In addition, a void portion 5 formed of nano-order communication holes is formed. The opening in the surface 20a formed as the outlet of the removal material constitutes a nano-order opening 20c.
In this way, as shown in FIG. 7, the film body upper layer portion 20B is formed between the boundary surface BS and the surface 20a. Between the boundary surface BS and the bottom surface 2b, the base film 20 remains so that the film body base layer portion 2A is formed. In this way, the film body 21 is formed from the base film 20.

  In the membrane body 21, the membrane body upper layer portion 20B has a nanoporous structure composed of a material obtained by removing or reducing the removal material from the material of the base membrane 20, as schematically shown in FIG.

Thereafter, the release agent 3 is introduced into the gap 5 of the membrane body 21.
The method for introducing the release agent 3 is not particularly limited as long as the release agent 3 can be introduced into the gap 5. For example, as shown in FIG. 10, after the release agent introduction material 50 containing the release agent 3 is disposed on the surface 20a of the membrane body 21, the release agent introduction material 50 is heated to introduce the release agent. It may be introduced by moving the release agent 3 in the material 50 into the gap 5.
For example, the release agent introduction material 50 may be constituted by the release agent 3 itself or a film containing the release agent 3. In this case, as a film forming method of the release agent introducing material 50, for example, vapor deposition, RF sputtering, DC sputtering, magnetron sputtering, ion beam sputtering, ion plating, ion mixing, or the like may be used.
For example, the release agent introduction material 50 is composed of a base member and a release agent 3 contained movably toward the outside inside the base member or a material component from which the release agent 3 is generated. Also good. Here, the material component from which the release agent 3 is generated means a substance that becomes the release agent 3 when it comes out of the base material or moves into the gap 5. In this case, for example, if the release agent 3 or the material component from which the release agent 3 is generated can be contained in the glass, the release agent 3 or the release agent 3 is generated as the release agent introduction material 50. A glass plate containing a material component to be used may be used.
For example, the release agent introduction material 50 may be configured by a release agent 3 or a coating film made of a dispersion in which a material component for generating the release agent 3 is dispersed.

When the release agent 3 is introduced into the gap 5 from the release agent introduction material 50, the release agent introduction material 50 is removed from the surface 20a.
For example, when the release agent introduction material 50 is formed on the surface 20a, the release agent introduction material 50 is removed by an appropriate removal process. At this time, when the thickness of the membrane body upper layer portion 20B in the membrane body 21 exceeds t2, the upper portions of the membrane body upper layer portion 2B and the gap portion 5 are removed until the thickness of the membrane body upper layer portion 2B reaches t2. Processed. More preferably, this removal process includes at least a mirror polishing finish.
When the removal processing is performed, a surface 2a lower than the surface 20a is formed on the upper part 2B of the film body. In this way, the membrane body 2 in a state where the release agent 3 is introduced into the gap 5 is manufactured.
For example, when the release agent introduction material 50 is configured by a member that can move from the surface 20a such as a glass plate, the release agent introduction material 50 is simply moved from the surface 20a and removed.
When the thickness of the membrane body upper layer 2B in the membrane body 21 exceeds t2, the membrane body upper layer until the thickness of the membrane body upper layer 2B reaches t2 after the release agent introduction material 50 is moved. 20B and the upper part of the space 5 are removed. More preferably, the removal processing includes mirror polishing finishing.
However, even if the surface 20a of the film body upper layer portion 20B is not mirror-polished, the surface 20a is formed in advance at the same height as the surface 2a if the surface accuracy required for the lower mold 10A is obtained.

In this way, as shown in FIG. 2, the release film 4 is formed on the molding surface 1a of the substrate 1A. Thereby, lower mold | type 10A is manufactured.
The upper mold 10B is manufactured in the same manner as described above except that the substrate 1B is prepared instead of the substrate 1A, and the release film 4 is formed on the molding surface 1b of the substrate 1B.

Molding of the optical element using the lower mold 10A and the upper mold 10B is performed as follows.
As shown in FIG. 1, the mold assembly 10 is assembled so that the molding material G is disposed therein.
Thereafter, the mold assembly 10 is sandwiched between heating plates 11A and 11B arranged in a dust-proof processing chamber. The heating plate 11A supports the flange portion 10d of the lower mold 10A from below. The heating plate 11B contacts the flange portion 10f of the upper mold 10B from above. The heating plate 11B can pressurize the upper die 10B toward the lower die 10A by a press mechanism (not shown).
A heater 12 is disposed inside each of the heating plates 11A and 11B. For example, a ceramic cartridge heater may be used as the heater 12.
The heater 12 heats the heating plates 11A and 11B. The heater 12 continues heating until the temperature of the mold surfaces 10a and 10b of the lower mold 10A and the upper mold 10B reaches the molding temperature by heat conduction from the heating plates 11A and 11B. The heater 12 maintains the temperature of the mold surfaces 10a and 10b at the molding temperature until the molding is completed. The molding temperature is set to a temperature at which the molding material G is easily deformed, for example, a temperature above the yield point.

The molding material G is heated by radiation from the mold surfaces 10a and 10b and heat conduction from the contact portions of the mold surfaces 10a and 10b. When the entire molding material G reaches a temperature higher than the yield point, the heating plate 11B is lowered by a press mechanism (not shown). As the heating plate 11B is lowered, the molding material G between the lower mold 10A and the upper mold 10B is press-molded.
During the press molding, the release films 4 constituting the mold surfaces 10a and 10b are in contact with the molding material G while being heated to the molding temperature. The release agent 3 is exposed in the opening 2c of the surface 2a of the film body upper layer 2B in each release film 4. Since the release agent 3 is contained in the film body upper layer portion 2B in a state where it can move to the surface 2a at the molding temperature, it is interposed between the surface 2a and the molding material G. For example, the mold release agent 3 moves between the surface 2a and the molding material G from the opening 2c by melting or volatilizing at the molding temperature. However, since the molding material G is pressurized between the surfaces 2a of the molding surfaces 1a and 1b, the minimum thickness is reduced between the surface 2a and the surface of the molding material G according to the applied pressure. Only the limited release agent 3 is interposed, and the remaining release agent 3 is confined in the gap 5.

When the molding material G is pressed into a shape having a predetermined lens thickness, the press mechanism is stopped. When the deformation of the pressed molding material G is stabilized, heating of the heating plates 11A and 11B is stopped. As a result, heat radiation cooling of the mold assembly 10 is started. The shape of the mold surfaces 10a and 10b is transferred to the molding material G in the molding die assembly 10 to form a molded product by press molding.
When a cooling plate for cooling the molding die assembly 10 is provided in the molding chamber, the clamping of the heating plates 11A and 11B is released, and then the molding die assembly 10 is moved to the cooling plate. Then, the mold assembly 10 is cooled. The components melted at the molding temperature in the mold release agent 3 are solidified by being cooled below their melting points.
When the molded product is cooled to a temperature at which it can be removed, the molded product is removed from the molding die assembly 10. At this time, the lower mold 10A and the upper mold 10B have a mold release performance possessed by the material of the film body 2 in the mold release film 4 and a mold release performance possessed by the mold release agent 3 interposed between the surface 2a and the molded product. Combined with, the mold is removed smoothly. In this way, a molded product having the outer shape of the optical element is manufactured.
The release agent 3 that has not moved to the outside of the gap 5 during molding is solidified inside the gap 5 and therefore is not pulled out to the outside during demolding.
The demolded molded product is subjected to machining such as centering or an appropriate film coating as necessary.
In this way, an optical element is manufactured.

As described above, according to the method for manufacturing an optical element using the lower mold 10A and the upper mold 10B of the present embodiment, the mold release agent 3 occupying a part of the gap 5 is formed on the surface in one molding. As a result of moving to 2a, for example, it volatilizes or adheres to the molding material G and a part of the release agent 3 is consumed. However, when the release agent 3 is made of an inorganic material such as a metal having a melting point lower than the molding temperature, the amount consumed by volatilization is significantly less than that of an organic material having a lower melting point.
In this way, a part of the release agent 3 is consumed by one molding, but when the next molding is performed, the release agent 3 remaining in the gap 5 is the surface in the same manner as described above. Move to 2a. For this reason, the release performance by the release agent 3 is maintained while the release agent 3 in the gap 5 of the membrane body upper layer 2B remains. For this reason, according to the lower mold | type 10A and upper mold | type 10B of this embodiment, even if it repeats high temperature shaping | molding, a mold release performance does not fall easily.

On the other hand, for example, when a conventionally known organic mold release agent is used by being applied to the molding surface of a mold that does not have the gap 5, the organic mold release agent is molded once. Is almost all consumed. Even if a part of the organic release agent remains, if the difference between the melting point of the organic release agent and the molding temperature is large, the organic release agent is decomposed or modified during molding. For this reason, even if the organic release agent remains, the release performance at the time of application cannot be obtained, but rather, it tends to cause fusion. For this reason, the organic mold release agent or the organic mold release agent remaining on the mold surface needs to be cleaned for each molding.
According to such a conventional optical mold and molding method, it is difficult to continuously perform good molding a plurality of times by applying the mold release agent once. Therefore, every time molding is performed, it is necessary to repeat the application of the organic release agent and the molding after the molding, so that a lot of time is required for the molding preparation and the molding die maintenance.
Furthermore, since the organic release agent fixed to the molding surface in a modified state cannot be easily cleaned, glass fusion tends to be induced from the fixing portion of the organic release agent when molding is repeated. For this reason, the mold life is also shortened.
As described above, an example in which an organic release agent is used for molding has been described. However, even when an inorganic material that is difficult to denature at a molding temperature is used as a release agent, the release film does not have a void. It is the same that it takes time and effort to reapply the release agent for each molding.

According to the lower mold 10A and the upper mold 10B of the present embodiment, since the gap 5 is formed inside a metal or alloy containing a noble metal, the gap 5 can be obtained even when the release agent 3 has moved to the outside. Remains without being crushed.
For this reason, when the mold release agent 3 contained in the membrane main body upper layer portion 2B is reduced due to repetition of molding, a step of replenishing the gap portion 5 with a new mold release agent 3 may be performed. In the step of replenishing the release agent 3, the method used when the release agent 3 is introduced into the gap 5 during the production of the release film 4 is used.
Thus, in the above-described optical element manufacturing method, when a step of replenishing the release agent 3 is added, the release films 4 of the lower mold 10A and the upper mold 10B can be used for a longer period of time. Even when the release agent 3 is consumed, the membrane body 2 can be reused. Therefore, the lower mold 10A and the upper mold 10B are compared with the case where the release film 4 is re-formed when the release agent 3 is consumed. Running costs are reduced.

[Second Embodiment]
The manufacturing method of the optical element shaping | molding die of the 2nd Embodiment of this invention is demonstrated.
11-13 is process explanatory drawing of the manufacturing method of the optical element shaping | molding die of the 2nd Embodiment of this invention.

  The method for manufacturing an optical element molding die according to the present embodiment is used for manufacturing a release film 4 similar to that in the first embodiment. Hereinafter, an example of manufacturing the lower mold 10A will be described with a focus on differences from the first embodiment.

First, in the present embodiment, a base material 1A is prepared in the same manner as in the first embodiment.
Thereafter, a release film 4 is formed on the molding surface 1a. In the present embodiment, the mold release film 4 is formed by forming a base film, forming a base film, forming a gap 5 in the base film, Introducing a release agent 3.
As shown in FIG. 11, first, a base film 30 is formed on the molding surface 1a. In the present embodiment, the base film 30 constitutes the film body base layer 2A. For this reason, the film thickness t4 of the base film 30 is equal to t1-t2 which is the layer thickness of the film body base layer portion 2A.
As the material of the base film 30, the same material as that of the film main body base layer portion 2A can be used. However, in the present embodiment, since the void portion 5 is not formed in the base film 30, the removal material for forming the void portion 5 included in the base film 20 may not be included.
As the film formation method of the base film 30, an appropriate film formation method exemplified as the film formation method of the base film 20 in the first embodiment is used.

Thereafter, as shown in FIG. 12, a base film 33 is formed on the surface 30 a of the base film 30. The base film 33 is used to form the film body upper layer part 2 </ b> B and the gap part 5.
The base film 33 includes a film main body material 32 and a removal material 35.
The film body material 32 is made of a metal or an alloy containing a noble metal element. The membrane body material 32 is made of the same material as the membrane body upper layer 2B. The film body material 32 may be different from or the same as the material of the base film 30 as long as the material has high adhesion to the base film 30.
The distribution of the film body material 32 is more preferably a distribution corresponding to the film body upper layer 2B to be formed. However, the distribution of the film main body material 32 may change as the removal material 35 moves during the removal process of the removal material 35 described later.

As the removal material 35, the same material as the removal material contained in the base film 20 in the first embodiment is used.
The distribution of the removal material 35 is more preferably a distribution corresponding to the gaps 5 to be formed. However, similar to the removal material in the base film 20 in the first embodiment, the distribution of the removal material 35 is described later by the removal material moving from the initial distribution state in the removal process of the removal material 35 described later. It may be a distribution in which the shape of the gap portion 5 is obtained.

As a method for forming the base film 33, an appropriate film forming method similar to that for the base film 20 is selected according to the material of the base film 33.
When a film forming method is used in which the unevenness of the surface 32a of the base film 33 is within the allowable range as the mold surface without requiring a finishing process such as mirror polishing, the film thickness t5 of the base film 33 is the upper layer of the film body. The layer thickness t2 is the same as that of the portion 2B.
When the irregularities on the surface 32a of the base film 33 fall within the allowable range as the mold surface, when a finishing process such as mirror polishing is necessary after film formation, the film thickness t5 of the base film 33 is set to the film body upper layer portion 2B. A thickness obtained by adding a finishing allowance to the layer thickness t2.

After the base film 33 is formed, the gap 5 is formed in the base film 33.
In the present embodiment, the removal material 35 is removed from the base film 33 schematically shown in FIG. 12, thereby forming the gap 5 as shown in FIG.
As a removal method of the removal material 35, for example, a method similar to the removal method of the removal material of the base film 20 in the first embodiment may be used.
Furthermore, in the present embodiment, even if the removal material 35 is completely removed, the gap 5 is formed only in the range of the film thickness of the base film 33. For this reason, as the removal material 35, for example, a material that can be completely removed from the base film 33 by being vaporized at a molding temperature or higher may be used.
When all the removal material 35 is removed from the base film 33, the type of the removal material 35 is not particularly limited. For example, the removal material 35 may be an inorganic material or an organic material.
When a part of the removal material 35 remains in the base film 33, a material having a melting point higher than the molding temperature and stable inside the film body material at the molding temperature is used as the removal material 35.
In the following, an example in which almost all the removal material 35 is removed from the base film 33 will be described.

By removing the removal material 35 from the base film 33 by the appropriate removal method described above, the void portion 5 composed of nano-order communication holes is formed in the region where the removal material 35 is distributed (FIG. 8). 9). The opening of the surface 32a formed as the outlet of the removal material constitutes the nano-order opening 20c, as in the first embodiment.
In the present embodiment, the gap 5 is formed so as to penetrate in the film thickness direction of the base film 33. The lower end of the gap 5 reaches the surface 30 a of the base film 30. The surface 30a of the base film 30 constitutes a boundary surface BS between the film body base layer 2A and the film body upper layer 20B in the present embodiment (see FIG. 13).
A membrane main body upper layer portion 30B is formed between the boundary surface BS and the surface 32a. Between the boundary surface BS and the bottom surface 30b of the release agent introducing material 50, a film body base layer portion 2A made of the material of the base film 33 is formed. In this way, the membrane body 31 in which the membrane body base layer portion 2A and the membrane body upper layer portion 30B are laminated is formed.

  In the membrane body 31, the membrane body upper layer portion 30 </ b> B has a nanoporous structure constituted by the membrane body material 32 by removing the removal material 35 from the material of the base membrane 33.

  Thereafter, the release agent 3 is introduced into the gap 5 of the membrane body 31 in the same manner as in the first embodiment. Furthermore, if necessary, the surface 32a is finished to form a release film 4 as shown in FIG. In this way, the lower mold 10A including the release film 4 is manufactured.

As described above, according to the manufacturing method of the optical element molding die of the present embodiment, the lower mold 10A and the upper mold 10B including the release film 4 similar to those of the first embodiment can be manufactured. The same operation as that of the first embodiment is provided.
Further, in this embodiment, the release film 4 is manufactured starting from a two-layer structure of the base film 30 and the base film 33.
For this reason, since the removal material 35 has only to be added to the base film 33, a material having poor adhesion to the molding surfaces 1a and 1b can also be used as the removal material 35.
Furthermore, since almost all of the removal material 35 is removed from the base film 33, the gap portion 5 extending in substantially the entire range of the film thickness of the base film 33 can be easily formed, so that the depth of the gap portion 5 can be easily controlled. become.
According to the present embodiment, the removal material 35 is completely removed from the base film 33, so that the removal material 35 is not included in the entire release film 4. For this reason, in this embodiment, even if it is a material which the film | membrane intensity | strength of the release film 4 falls when it remains in the release film 4, it can be used as the removal material 35.

[Third Embodiment]
A release film and an optical element molding die according to a third embodiment of the present invention will be described.
FIG. 14 is a schematic cross-sectional view showing the configuration of the release film according to the third embodiment of the present invention.

As shown in FIG. 14, the release film 44 of the present embodiment includes a film body 42 instead of the film body 2 in the release film 4 of the first embodiment.
The release film 44 is used in place of the release film 4 in the lower mold 10A and the upper mold 10B in the first embodiment. Hereinafter, a description will be given centering on differences from the first embodiment.

The membrane body 42 is configured in the same manner as the membrane body upper layer portion 2B in the first embodiment except that the film thickness is t1. That is, the membrane main body 42 is configured in the same manner as t1 = t2 in the membrane main body 2 of the first embodiment.
The bottom surface 42b of the membrane body 42 is in close contact with the molding surface 1a (1b) of the base material 1A (1B). The surface 42a of the membrane body 42 is the outermost surface of the membrane body 42 that contacts the molding material G during molding.
The membrane body 42 is formed with a gap 5 similar to that of the first embodiment except that it extends from the bottom surface 42b to the surface 42a. As shown in FIGS. 3 and 4, the gap 5 in the membrane main body 42 opens as an opening 2 c similar to that in the first embodiment on the surface 42 a. At least a part of the gap 5 is open at the bottom surface 42b.
The gap 5 in the present embodiment is formed in the same shape as in the first embodiment except that the length in the film thickness direction is different. The release agent 3 similar to that in the first embodiment is introduced into the gap 5 in the present embodiment.
The material of the membrane body 42 is made of the same material as that of the membrane body upper layer 2B in the first embodiment.

The membrane body 42 having such a configuration may be manufactured, for example, by extending a formation region in the film thickness direction of the gap 5 in the membrane body 2 in the first embodiment to the molding surface 1a (1b). .
For example, the film body 42 is formed by forming the base film 33 similar to that in the second embodiment on the molding surface 1a (1b) with a film thickness t1, and then removing the material 35 in the same manner as in the second embodiment. May be produced by removing
As a method for introducing the release agent 3 into the gap 5 in the film body 42 formed on the molding surface 1a (1b), the same method as in the first embodiment is used.

According to the lower mold 10A and the upper mold 10B including the release film 44 of the present embodiment, the release agent 3 is movably dispersed on the surface 42a at the molding temperature in the release film 44. The same operation as that of the first embodiment is provided.
Furthermore, in this embodiment, since the release agent 3 is dispersed throughout the film thickness direction of the release film 44, more release agent 3 is added to the release film than in the first embodiment. 44. For this reason, the number of shots that can be satisfactorily molded in the lower mold 10A and the upper mold 10B is improved.

  In the above description of each embodiment, an example in which the molding material is glass has been described. However, the molding material for the optical element may be a resin.

  In the above description of each embodiment, an example in which the removal material in the base film is in the form of particles has been described. However, the removal material may have an appropriate shape such as a fiber shape, a rod shape, or a plate shape.

  Next, Examples 1 to 3 of the mold for molding an optical element and the method for manufacturing the same according to the first and second embodiments will be described focusing on the method for manufacturing each release film. Since each manufacturing method is common to the lower mold 10A and the upper mold 10B, the following description will focus on the lower mold 10A.

[Example 1]
Example 1 is an example relating to the first embodiment.
First, the base material 1A manufactured by the cemented carbide having the shape of the lower mold 10A excluding the release film 4 was prepared. The molding surface 1a of the substrate 1A was mirror-polished by mechanical polishing.
Thereafter, a base film 20 (t3 = 3 (μm)) made of platinum and rhenium dispersed in platinum was formed on the molding surface 1a of the substrate 1A by ion beam sputtering (see FIG. 6). Platinum and rhenium were exposed on the surface 20a of the base film 20, respectively. In this embodiment, platinum corresponds to the film body material and rhenium corresponds to the removal material.
The base material 1A on which the base film 20 was formed was subjected to a heat treatment at 400 ° C. for 15 minutes in an electric furnace in an air atmosphere in order to oxidize rhenium. Thereby, the film | membrane main body 21 which has a nanoporous structure in the upper layer part was formed (refer FIG. 7).
TEM observation of the surface 20a of the film body 21 was performed. An opening 20c having an inner diameter of about 5 nm to 15 nm was confirmed on the surface 20a.

A process of forming the film body 21 by the heat treatment will be briefly described. Rhenium oxide has a melting point of 360 ° C. and is a substance that sublimes. For this reason, when rhenium exposed in the opening 20c of the base film 20 is oxidized to generate rhenium oxide, the rhenium oxide is sublimated and moves from the inside of the base film 20 into the electric furnace. Since rhenium inside the base film 20 is oxidized by oxygen entering from the void 5 formed by sublimation of rhenium oxide, the void 5 extends into the base film 20. Thus, it is considered that the membrane main body 21 was formed.
The depth at which the gap 5 is formed depends on the heat treatment conditions such as the heating temperature and the heating time, for example.

Thereafter, the release agent 3 was introduced into the gap 5 by using a glass plate containing zinc as the release agent 3 as the release agent introduction material 50. Specifically, with the release agent introduction material 50 placed on the surface 20a of the film body 21 (see FIG. 10), a heat treatment was performed at 600 ° C. for 60 minutes in an electric furnace in a nitrogen atmosphere.
Thereby, the zinc contained in the release agent introducing material 50 was introduced into the gap 5 through the opening 20c, and the lower mold 10A having the release film 4 was manufactured.
Similarly, samples for observation of the release film 4 and the lower mold 10A were prepared. The release film 4 in the observation sample was subjected to FIB (focused ion beam) processing, and the processing cross section was measured by TEM / EDS (transmission electron microscope / energy dispersive X-ray analysis). According to the measurement results, the zinc element was distributed from the surface 20a of the base film 20 to a depth of 0.5 μm. For this reason, it is considered that zinc was introduced into the gap 5 having a depth in the range of 0.5 μm.

Similarly, the upper mold | type 10B was manufactured. Using the lower mold 10A and the upper mold 10B of this example, the glass was press-molded at a molding temperature of 620 ° C. to manufacture the optical element shape.
While molding of 100 shots was performed, seizure of the molded product did not occur. No defects such as spiders occurred on the surface of each molded product.
Since zinc melts at a molding temperature of 620 ° C., it is considered that the mold release performance of the mold is improved by being interposed between the molding material G and the mold release film 4 through the opening 2 c of the mold release film 4.

[Example 2]
Example 2 is an example relating to the first embodiment.
First, a base material 1A made of silicon carbide having the shape of the lower mold 10A excluding the release film 4 was prepared.
Thereafter, a base film 20 (t3 = 2 (μm)) made of platinum and molybdenum dispersed in platinum was formed on the molding surface 1a of the substrate 1A by ion beam sputtering (see FIG. 6). Platinum and molybdenum were exposed on the surface 20a of the base film 20, respectively. In this embodiment, platinum corresponds to the film body material and molybdenum corresponds to the removal material. Molybdenum oxides sublime, like rhenium oxides.
The base material 1A on which the base film 20 was formed was oxidized in an electric furnace in an air atmosphere in order to oxidize molybdenum. In the electric furnace, a tubular electric furnace having a length of 300 mm surrounding the quartz tube is provided at the center in the longitudinal direction of the quartz tube having a diameter of 50 mm and a length of 1000 mm. Air is introduced from one side of the quartz tube and discharged from the other side. A xenon excimer lamp is provided on the quartz tube on the air introduction side so that the inside of the quartz tube can be irradiated. The xenon excimer lamp was turned on and the interior of the quartz tube was irradiated, and heating was performed at 550 ° C. for 30 minutes in an electric furnace. The xenon excimer lamp was irradiated because oxygen in the atmosphere inside the quartz tube was photolyzed to generate active oxygen and ozone. This is to promote.
Thereafter, the xenon excimer lamp was turned off, and heat treatment was performed at 700 ° C. for 2 hours in an electric furnace. As a result, molybdenum oxide was sublimated, and a film body 21 having a nanoporous structure in the upper layer portion was formed (see FIG. 7).

Thereafter, tin as the release agent 3 was deposited on the surface 20 a of the film body 21. In this embodiment, the tin vapor deposition layer was used as the release agent introducing material 50 (see FIG. 10).
The film body 21 on which the tin was deposited was subjected to heat treatment at 350 ° C. for 60 minutes in an electric furnace in a nitrogen atmosphere.
Thereby, tin was melted and introduced into the gap 5 through the opening 20c. Then, the lower mold | type 10A which has the release film 4 was manufactured by mirror-polishing the surface of the film | membrane main body 21. FIG.

Similarly, the upper mold | type 10B was manufactured. Using the lower mold 10A and the upper mold 10B of this example, glass was press-molded at a molding temperature of 800 ° C. to produce a molded product having the shape of an optical element.
While molding of 100 shots was performed, seizure of the molded product did not occur. No defects such as spiders occurred on the surface of each molded product.
Since tin melts at a molding temperature of 800 ° C., it is considered that the mold release performance of the mold is improved by being interposed between the molding material G and the mold release film 4 through the opening 2 c of the mold release film 4.

[Example 3]
Example 3 is an example related to the second embodiment.
First, the base material 1A manufactured by the cemented carbide having the shape of the lower mold 10A excluding the release film 4 was prepared.
Thereafter, a base film 30 (t4 = 1 (μm)) made of gold was formed on the molding surface 1a of the substrate 1A by vapor deposition (see FIG. 11).
Thereafter, a base film 33 having a film thickness t5 was applied to the surface 30a of the base film 30 (see FIG. 12). Specifically, the base film 33 is a gold nanoparticle dispersed paste to which polyvinyl alcohol is added. This gold nanoparticle-dispersed paste was produced by adding polyvinyl alcohol to a gold nanoparticle solution obtained by reducing chloroauric acid with sodium citrate and concentrating it by centrifugation.
Gold and polyvinyl alcohol were exposed on the surface 32a of the base film 33, respectively. In this embodiment, gold corresponds to the film body material 32 and polyvinyl alcohol corresponds to the removal material 35.
The base material 1A on which the base film 30 and the base film 33 were formed was heated at 500 ° C. for 30 minutes in an electric furnace in an air atmosphere in order to burn off polyvinyl alcohol. Thereby, polyvinyl alcohol was burned off, and the film body upper layer portion 30B having a nanoporous structure was formed by the remaining gold particles (see FIG. 13). The gold particles constituting the bottom surface 30b of the film body upper layer portion 30B were brought into close contact with the surface 30a of the base film 30 and integrated. Thereby, the film main body 31 having the film main body base layer portion 2A (the base film 30) and the film main body upper layer portion 30B was formed.

Thereafter, a nano-dispersion in which antimony pentoxide serving as the release agent 3 was dispersed in a solvent composed of water and triethanolamine was applied to the surface 32a of the film body 31. In the present example, the coating film of the antimony pentoxide nanodispersion was used as the release agent introducing material 50 (see FIG. 10).
The film body 31 to which the nano dispersion of antimony pentoxide was applied was subjected to a heat treatment at 350 ° C. for 60 minutes in an electric furnace in an air atmosphere. As a result, antimony pentoxide was absorbed inside the gap 5.
Then, the lower mold | type 10A which has the release film 4 was manufactured by mirror-polishing the surface 32a of the film | membrane main body 31 in which the antimony pentoxide was absorbed. As the polishing liquid used for mirror polishing, an alumina-based abrasive dispersion was used.

Similarly, the upper mold | type 10B was manufactured. Using the lower mold 10A and the upper mold 10B of this example, glass was press-molded at a molding temperature of 400 ° C. to produce a molded article having the shape of an optical element.
While 300 shots were molded, no seizure of the molded product occurred. No defects such as spiders occurred on the surface of each molded product.
Since antimony pentoxide melts at a molding temperature of 400 ° C., it is considered that the mold release performance of the mold is improved by being interposed between the molding material G and the mold release film 4 through the opening 2 c of the mold release film 4. .

[Comparative example]
In order to compare with Examples 1 to 3, a molding die of a comparative example was manufactured. In the molding die of the comparative example, a platinum release film was formed instead of the release film 4 of the lower mold 10A and the upper mold 10B of Example 1. In the method for producing an optical element using the molding die of the comparative example, the surface of the release film was coated with an organic release agent obtained by diluting glycerin with alcohol, under the same molding conditions as in Example 1. The optical element was molded.
When molding of 30 shots was performed, seizure of the molded product occurred and spiders were also generated on the surface of the molded product. Therefore, the lifetime as a mold for molding was remarkably shortened compared with Examples 1-3.
This is considered to be because the organic release agent component decomposed at the molding temperature adhered to the release film and the surface of the molded product.

The preferred embodiments and examples of the present invention have been described above, but the present invention is not limited to these embodiments and examples. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the present invention.
Further, the present invention is not limited by the above description, and is limited only by the appended claims.

1a, 1b Molding surface 1A, 1B Base material 2, 21, 31, 42 Membrane body 2a, 20a, 30a, 32a, 42a Surface 2A Membrane body base layer 2B, 20B, 30B Membrane body upper layer 2c, 20c Opening 3 Separation Molding agent 4, 44 Release film 5 Gap 10a, 10b Mold surface 10A Lower mold (Optical element molding mold)
10B Upper mold (mold for optical element molding)
0, 33 Base film 30 Base film 32 Film body material 35 Removal material 50 Release agent introduction material G Molding material

Claims (10)

A film body made of a metal or alloy containing a noble metal element, which does not melt at the molding temperature,
At the molding temperature, a release agent dispersed inside the membrane body in a state movable to the surface in contact with the molding material in the membrane body,
A release film. The release agent is dispersed in a range less than the thickness of the membrane body from the surface,
The release film according to claim 1. The melting point of the release agent is lower than the molding temperature,
The release film according to claim 1 or 2. The release agent is an inorganic material.
The release film according to claim 3. The membrane body has a nanoporous structure in a range in which the release agent is dispersed.
The release film according to any one of claims 1 to 4. Comprising the release film according to any one of claims 1 to 5,
Optical element mold. Comprising at least a part of a mold body and preparing a substrate on which a molding surface is formed;
Forming a base film having a film body material made of a metal or alloy containing a noble metal element and a removal material dispersed in the film body material on the surface of the base material;
Removing at least a portion of the removal material from the base film to form a void portion communicating from the inside of the base film to the surface of the base film;
Introducing a release agent into the void,
The manufacturing method of the type | mold for optical element shaping | molding containing. Comprising at least a part of a mold body and preparing a substrate on which a molding surface is formed;
Forming a base film made of a metal or alloy containing a noble metal element on the surface of the substrate;
Forming a base film having a film body material made of a metal or an alloy containing a noble metal element and a removal material dispersed in the film body material on the surface of the base film;
Removing at least a portion of the removal material from the base film to form a void portion communicating from the inside of the base film to the surface of the base film;
Introducing a release agent into the void,
The manufacturing method of the type | mold for optical element shaping | molding containing. Comprising at least a part of a mold body and preparing a substrate on which a molding surface is formed;
Forming a base film having a metal or alloy containing a noble metal element on the surface of the substrate;
Forming a nanoporous structure in the base film having a minute opening on the surface of the base film, and a void extending from the opening to the inside of the base film;
Introducing a release agent into the void,
The manufacturing method of the type | mold for optical element shaping | molding containing. Molding an optical element by molding the molding material using a mold for molding an optical element including the release film according to any one of claims 1 to 5;
After molding a plurality of the optical elements, replenishing the release agent inside the release film;
The method for manufacturing the optical element is repeated.

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