JP6820237B2 - Mold release film, optical element molding mold, optical element molding mold manufacturing method, and optical element manufacturing method - Google Patents

Description

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

A method for manufacturing an optical element is known in which a glass material for molding is heated to a molding temperature equal to or higher than the softening point and pressed by an optical element molding mold.
Since the glass material heated to a high temperature is easily fused with the optical element molding mold, a release film is often formed on the molding surface of the optical element molding mold. However, since the release film deteriorates with time when molding is repeated, the release film needs to be re-deposited on a regular basis.
It is also known that a release agent is interposed between the molded surface and the glass material in order to extend the life of the release film. An organic compound is used as the release agent.
For example, Patent Document 1 describes a method for forming a glass in which an organic compound that thermally decomposes when the glass material is heated and softened to form a carbon thin film is applied to the glass material before heating.

Japanese Unexamined Patent Publication No. 11-116253

However, since the conventional mold release agent is consumed by being decomposed or volatilized by one molding, the mold release agent is applied to the molding material or the molding surface of the optical element molding mold 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 during molding to form carbon, all the applied mold release agents are decomposed by one molding. Therefore, there is a problem that the production efficiency is lowered by the application work of the release agent performed for each molding.
Further, in the mold release agent composed of an organic compound, a product due to thermal decomposition may remain on the surface of the molded product. In this case, depending on the characteristics of the residue, the residue may cause cloudiness on the surface of the molded product.

The present invention has been made in view of the above problems, and is a method for manufacturing a release film, an optical element molding die, and an optical element molding die whose mold release performance does not easily deteriorate even if high temperature molding is repeated. , And a method of manufacturing an optical element.

In order to solve the above problems, the release film of the first aspect of the present invention is a release film used for an optical element molding mold for molding an optical element by pressing a glass material as a molding material. a is the formed on the optical element forming mold surface, a metal or an alloy containing a noble metal element, a film body which does not melt at the molding temperature at the molding temperature, and the molding material in said film body A mold release agent dispersed inside the film body in a state of being movable on a surface in contact with the film is provided.

In the release film, the release agent may be dispersed from the surface to a range less than the thickness of the film body.
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.

The optical element molding mold of the second aspect of the present invention includes the above-mentioned mold release film.

The method for producing an optical element molding mold according to a third aspect of the present invention comprises preparing a base material that constitutes at least a part of the molding mold main body and has a molding surface formed to be transferred to a glass material. 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 is formed on the surface of the mold body, and the removal from the base film. By removing at least a part of the material, a gap portion communicating from the inside of the base film to the surface of the base film is formed, and a mold release agent is introduced into the gap portion.

The method for producing an optical element molding mold according to a fourth aspect of the present invention comprises preparing a base material that constitutes at least a part of the molding mold main body and has a molding surface formed to be transferred to a glass material. A base film made of a metal or alloy containing a noble metal element is formed on the surface of the base material, and a film body material made of a metal or alloy containing a noble metal element and the film body material are formed on the surface of the base film. By forming a base film having the dispersed removal material and removing at least a part of the removal material from the base film, voids communicating from the inside of the base film to the surface of the base film. It includes forming a portion and introducing a mold release agent into the gap portion.

The method for producing an optical element molding mold according to a fifth aspect of the present invention comprises preparing a base material that constitutes at least a part of the molding mold main body and has a molding surface formed to be transferred to a glass material. A base film having a metal or alloy containing a noble metal element is formed on the surface of the molding die body, and a minute opening is provided on the surface of the base film, and a gap is formed inside the base film from the opening. The nanoporous structure in which the portion extends is formed on the base film, and a mold release agent is introduced into the void portion.

The method for manufacturing an optical element according to a sixth aspect of the present invention is to mold the optical element by molding the molding material using the optical element molding mold provided with the release film, and to form the optical element. After molding a plurality of the mold release agents, replenishing the mold release agent inside the mold release film is repeated.

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

It is a schematic vertical sectional view which shows an example of the optical element molding mold of 1st Embodiment of this invention. It is a schematic cross-sectional view which shows the structure of the release film of 1st Embodiment of this invention. It is a schematic A view enlarged view in part B in FIG. FIG. 3 is a sectional view taken along line CC in FIG. It is a process explanatory drawing of the manufacturing method of the optical element molding mold of 1st Embodiment of this invention. It is a process explanatory drawing of the manufacturing method of the optical element molding mold of 1st Embodiment of this invention. It is a process explanatory drawing of the manufacturing method of the optical element molding mold of 1st Embodiment of this invention. It is a schematic E view enlarged view in the F part in FIG. 7. FIG. 8 is a sectional view taken along line HH in FIG. It is a process explanatory drawing of the manufacturing method of the optical element molding mold of 1st Embodiment of this invention. It is a process explanatory drawing of the manufacturing method of the optical element molding mold of the 2nd Embodiment of this invention. It is a process explanatory drawing of the manufacturing method of the optical element molding mold of the 2nd Embodiment of this invention. It is a process explanatory drawing of the manufacturing method of the optical element molding mold of the 2nd Embodiment of this invention. It is a schematic cross-sectional view which shows the structure of the release film of the 3rd Embodiment of this invention.

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

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

As shown in FIG. 1, the molding mold 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 die 10A, the upper die 10B, and the body die 10C are arranged in a positional relationship in which the central axes of the lower die 10A, the upper die 10B, and the body die 10C are coaxial with each other.
The molding mold assembly 10 is used for molding an optical element using the molding material G.
The molding material G is made of an appropriate glass material for forming an optical element. The molding material G is molded into an appropriate massive 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 mold assembly 10. The molding material G may have a shape such as a disk shape, a spheroid shape, or a shape similar to an optical element, in addition to the spherical shape.
The molding means of the molding material G may be molding, or may be machining such as cutting or polishing.
The type and shape of the optical element molded by the molding mold assembly 10 are not limited. For example, examples of optical elements include lenses, mirrors, prisms, parallel flat plates, and the like. In FIG. 1, as an example, a molding mold assembly 10 used when molding a biconvex lens with a flange is drawn.

The lower mold 10A is made of a substantially cylindrical member having a cylindrical side surface 10c. The lower mold 10A has a mold surface 10a formed at the first end portion in the axial direction (the upper end portion shown 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 formed by a combination of a concave surface forming the convex lens surface and a flat surface forming the flange surface.
A flange portion 10d is formed at the second end portion of the lower mold 10A opposite to the first end portion in the axial direction. 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 10a is composed of the release film 4. The release film 4 is formed on the molding surface 1a formed on the base material 1A.
The base material 1A is made of a material having high hardness and good heat resistance, such as cemented carbide containing tungsten carbide (WC) as a main component, silicon carbide, and carbon. The base material 1A may constitute the entire lower mold 10A excluding the release film 4. The base material 1A may be arranged only at the first end portion of the lower mold 10A. The entire lower mold 10A excluding the release film 4 constitutes the molding mold main body. Therefore, the base material 1A constitutes at least a part of the molding die main body.
The molding surface 1a has a shape similar to the surface of the optical element to be molded. The molded surface 1a is mirror-polished. For example, the surface accuracy of the molded surface 1a may be 0.15 μm or less in terms of PV value. For example, the surface roughness of the molded surface 1a may be 3 nm or less in 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 a material that does not melt at the molding temperature. As the composition of the film body 2, an appropriate composition that is unlikely to be fused with the molding material G is used. Examples of the noble metal element contained in the film body 2 include platinum (Pt), gold (Au), iridium (Ir), osmium (Os), rhodium (Rh), ruthenium (Ru), and palladium (Pd). Be done. As the film body 2, one kind of noble metal alone or an alloy made of two or more kinds of noble metals may be used. The noble metal element does not easily cause a chemical reaction with the glass component at the molding temperature of the glass material during molding. Therefore, the releasability to the molded glass material is improved.
For example, one or more kinds of metals other than precious metals such as rhenium (Re), tantalum (Ta), and molybdenum (Mo) may be added to the film body 2.
Elements other than the noble metal added to the film body 2 may contain elements that can be removed from the film body 2 in order to form the void portion 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 film body 2 includes a film body base layer portion 2A and a film body upper layer portion 2B in this order from the molding surface 1a side.
The film body base layer portion 2A is a dense layered portion made of the material of the film body 2. The surface of the film body base layer portion 2A that is in close contact with the molding surface 1a constitutes the bottom surface 2b of the film body 2.
The film body upper layer portion 2B is formed so as to overlap the film body base layer portion 2A. The surface opposite to the film body base layer portion 2A constitutes the surface 2a of the film body 2. The surface 2a is the outermost surface of the film body 2 that comes into contact with the molding material G during molding.

As shown in FIG. 4, the upper layer portion 2B of the film body has a large number of void portions 5. The gap portion 5 is used to movably accommodate the release agent 3 described later. After the gap 5 is formed during the production of the film body 2, the 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. In FIGS. 3 and 4, an example of such an unused release film 4 is schematically drawn. As will be described later, even if the mold release agent 3 moves to the outside of the gap portion 5 during molding of the optical element, the shape of the inner peripheral surface of the gap portion 5 does not change.
In the following, even when the void portion 5 is described with reference to FIGS. 3 and 4, the description may be made on the premise that the release agent 3 is not introduced, if necessary.

The void portion 5 is formed so as to open on the surface 2a. Therefore, as shown in FIG. 3, an opening 2c by each gap 5 is opened on the surface 2a. In FIG. 3, for simplification of the illustration, the openings 2c are all drawn in a circular shape. However, the shape of the opening 2c is not limited to a circular shape. For example, the opening 2c may be formed in an elliptical shape, a polygonal shape, an elongated hole shape, or the like.
As shown in FIG. 4, the gap portion 5 extends from the opening 2c toward the lower side in the drawing toward the film body base layer portion 2A (not shown). Each void portion 5 may merge with another void portion 5 or may penetrate the other void portion 5. Each gap portion 5 may be branched into a plurality of portions toward the membrane body base layer portion 2A (not shown).

The length of each gap 5 in the layer thickness direction of the upper layer 2B of the film body does not have to be a constant value. Among the ends of the gap portion 5, the group of ends extending toward the bottom surface 2b and the virtual enveloping surface that smoothly contacts as a whole are the boundary surface BS (the boundary surface BS between the film body upper layer portion 2B and the film body base layer portion 2A. (See Fig. 2) is specified.
As shown in FIG. 2, the distance from the surface 2a to the boundary surface BS in the film thickness direction of the film body 2 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 layer thicknesses of the film body base layer portion 2A and the film body upper layer portion 2B are t1-t2 and t2 (however, 0 <t2 <t1), respectively. ).
The layer thickness t1 can be 0.2 μm or more and 3.0 μm.
The layer thickness t1-t2 of the base layer portion 2A of the film body is determined so that the film strength required for the release film 4 and the adhesion strength with respect to the molded surface 1a are required strengths. For example, assuming that 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 upper layer portion 2B of the film body is determined according to the required amount of the release agent 3 filled in the void portion 5. For example, assuming that 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 upper layer portion 2B of the film body is a layered portion sparser than the base layer portion 2A of the film body in a state where the release agent 3 is not filled. The gap portions 5 may have the same shape as each other, or may be regularly arranged. However, FIGS. 3 and 4 schematically show an example in which the shapes of the gaps 5 are different from each other and the arrangement is not regular.
The upper layer portion 2B of the membrane body may have a nanoporous structure in which at least a part of a large number of pores having a pore diameter on the order of nano-order communicate with each other.
The size of the cross section orthogonal to the stretching direction of each gap 5 is more preferably 1 nm or more and 20 nm or less. Here, the fact that the size of the cross section is 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.
It is more preferable that the inner diameter D of the opening 2c of each gap 5 on the surface 2a is also 1 nm or more and 20 nm.

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

The mold release agent 3 is composed of a material that does not easily adhere to at least one of the molding material G and the film body 2 in order to suppress fusion between the molding material G and the film body 2. As the release agent 3, 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 adheres to the surface is used.
The release agent 3 is dispersed inside the film body 2 in a state where it can be moved to the surface 2a at the molding temperature. Specifically, as shown in FIG. 4, the release agent 3 is introduced into the gap portion 5 of the upper layer portion 2B of the film body.
Here, the state in which the mold release agent 3 can be moved to the surface 2a at the molding temperature is not particularly limited as long as it can be moved by applying thermal energy corresponding to the molding temperature.
For example, even if a substance that allows the mold release agent 3 to move along the gap 5 by changing to a liquid phase or a gas phase depending on the molding temperature and reach the surface 2a from the opening 2c is used. 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 moves along the void 5 and is surfaced from the opening 2c as a result of causing chemical changes such as reduction, oxidation, and thermal decomposition by applying thermal energy corresponding to the molding temperature. A substance that produces a substance that can reach 2a may be used.

As the release agent 3, a substance capable of obtaining mold release performance may be selected depending on the difference in the coefficient of thermal expansion between the film body 2 and the molding material G. When the coefficient of thermal expansion of the release agent 3 is different from the coefficient of thermal expansion of at least one of the film body 2 and the molding material G, the interface between the release agent 3 and the surface 2a due to the difference in the coefficient of thermal expansion during cooling after molding. , Or, shear deviation in the plane direction occurs at the interface between the release agent 3 and the molding material G. Therefore, the molding material G can be easily released from the release film 4.

For example, examples of a material suitable as the release agent 3 include zinc, tin, antimony, and antimony pentoxide.

As shown in FIG. 1, the upper mold 10B is composed of a substantially cylindrical member having a cylindrical surface-shaped side surface 10e. The upper mold 10B has a mold surface 10b formed at the first end portion in the axial direction (the lower end portion shown 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 formed by a combination of a concave surface forming the convex lens surface and a flat surface forming the flange surface.
A flange portion 10f is formed at the second end portion of the upper die 10B opposite to the first end portion in the axial direction. The flange portion 10f extends radially outward from the side surface 10e of the upper die 10B.

As shown in FIG. 2, the mold surface 10b is composed of a mold 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 base material 1B. The base material 1B is made of the same material as the base material 1A.
Similar to 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 arranged only at the first end portion of the upper mold 10B. The entire upper mold 10B excluding the release film 4 constitutes the molding mold main body. Therefore, the base material 1B constitutes at least a part of the molding die main body.
The molding surface 1b has a shape similar to the surface of the optical element to be molded. The molded surface 1b is mirror-polished. The surface accuracy and surface roughness of the molded surface 1b are the same as those of the molded surface 1a.

As shown in FIG. 1, the body die 10C is a cylindrical member having an inner peripheral surface 10g that slidably fits the side surface 10c of the lower die 10A and the side surface 10e of the upper die 10B.
The axial length of the body die 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 die 10C can hold the lower die 10A and the upper die 10B in a coaxial positional relationship and guide the upper die 10B so as to be movable in the axial direction during molding.
The body type 10C may be made of an appropriate metal material or ceramics having heat resistance to the molding temperature. As an example, the material of the copper mold 10C in the present embodiment is a cemented carbide having high hardness and good heat resistance.

The molding die assembly 10 is assembled with the first ends of the lower die 10A and the upper die 10B inserted into the body die 10C. A molding material G weighed to a mass required for molding is arranged between the mold surfaces 10a and 10b.

A method for manufacturing the optical element molding mold of the present embodiment will be described.
FIGS. 5, 6 and 7 are process explanatory views of a method for manufacturing an optical element molding mold according to the first embodiment of the present invention. FIG. 8 is a schematic magnified view of E in FIG. 7. FIG. 9 is a sectional view taken along the line HH in FIG. FIG. 10 is a process explanatory view of a method for manufacturing an optical element molding mold 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 manufacturing method of the optical element molding mold of the present embodiment will be described by taking the lower mold 10A as an example. For simplicity, the base material 1A will be described as being formed in the shape of the molding body.

In order to manufacture the lower mold 10A, in the present embodiment, as shown in FIG. 5, the base material 1A on which the molding surface 1a is formed is prepared. However, FIG. 5 is a schematic cross-sectional view in which a part of the base material 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 an optical element at a molding temperature higher than the yield point of the molding material G.
As the material used for the base material 1A, a material that can withstand the molding temperature is selected. The material used for the base material 1A is formed into, for example, a shape in which the flange portion 10d protrudes from the end of the cylinder having the side surface 10c. After that, a molding surface 1a is formed at the end of the cylinder opposite to the flange portion 10d. In the finishing step of the molded surface 1a, mirror polishing is performed.
With the above, the base material 1A on which the molding surface 1a is formed is prepared.

After this, the release film 4 is formed on the molding surface 1a. In the present embodiment, in order to form the release film 4, a base film is formed, a gap 5 is formed in the base film, and a release agent 3 is introduced 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 closer to the molding surface 1a constitutes the film body base layer portion 2A (see FIG. 2). A film body upper layer portion 2B (see FIG. 2) is formed on the base film 20 near the surface 20a on the opposite side of the molding surface 1a. Therefore, as the material of the base film 20, at least the same material as the film body base layer portion 2A is included near the molding surface 1a, and the same material as the film body upper layer portion 2B is included near the surface 20a.
Specifically, the base film 20 includes a film body material commonly contained in the film body base layer portion 2A and the film body upper layer portion 2B, and a removal material that can be removed from the film body upper layer portion 2B. Here, the fact that the removal material can be removed from the upper layer portion 2B of the film body means that the removal material itself may be removable, or the removal material can be removed by thermal decomposition or chemical change. May be good.

The removal material is dispersed at least in the region where the upper layer 2B of the film body 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 the region where the upper layer portion 2B of the film body is formed. When the removing material is distributed in the region to be the base layer portion 2A of the film body, 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 removing material.
The removing material is removed from at least the region where the upper layer portion 2B of the film body is formed in order to form the void portion 5. Therefore, the removal material does not have to 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 void portion 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 moving the removal material from the initial distribution state in the removal process of the removal material described later.
For example, when the removal materials are distributed in minute units in the base film 20, the gaps 5 are formed in the base film 20 by repeating movement and aggregation in the base film 20 in the removal process described later. A shape may be formed.
For example, in the base film 20, when the removal material vaporizes and escapes to the outside of the base film 20, the surrounding membrane body material is blown off or deformed, so that the void portion 5 having a shape different from the initial distribution state 5 Shape may be formed.

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

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

After the base film 20 is formed, the gap portion 5 is formed in the base film 20.
In the present embodiment, as schematically shown in FIG. 7, the gap portion 5 is formed by removing the removing material in the base film 20 from the region to be the upper layer portion 2B of the film body.
As a method for removing the removal material, for example, a removal method may be performed in which the removal material is converted into a substance that easily volatilizes by a chemical reaction such as oxidation and then heated. For example, a removal method may be performed in which the removal material is converted into a easily meltable substance by a chemical reaction such as oxidation and then heated.
According to such a removal method of the removal material, the removal material in the base film 20 is sequentially removed from the portion exposed on the surface 20a, and therefore, as shown in FIGS. 8 and 9, the region where the removal material is distributed. In addition, a void portion 5 composed of nano-order communication holes is formed. The openings in the surface 20a formed as outlets for the removal material constitute the nano-order openings 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. The base film 20 remains between the boundary surface BS and the bottom surface 2b to form the film body base layer portion 2A. In this way, the film body 21 is formed from the base film 20.

In the film body 21, the upper layer portion 20B of the film body has a nanoporous structure composed of a material in which the material to be removed is removed or reduced from the material of the base film 20, as schematically shown in FIG.

After that, the release agent 3 is introduced into the gap 5 of the film 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 void portion 5. For example, as shown in FIG. 10, after the release agent introduction material 50 containing the release agent 3 is arranged on the surface 20a of the film 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 to the void 5.
For example, the release agent introduction material 50 may be composed of the release agent 3 itself or a film containing the release agent 3. In this case, as the film forming method of the release agent introduction material 50, for example, vapor deposition, RF sputtering, DC sputtering, magnetron sputtering, ion beam sputtering, ion plating, ion mixing and the like may be used.
For example, the release agent introduction material 50 is composed of a base member and a material component for producing a release agent 3 or a release agent 3 contained in the base member so as to be movable outward. May be good. Here, the material component in which the release agent 3 is produced means a substance that becomes the release agent 3 when it goes out from the base material or moves into the void portion 5. In this case, for example, if the material component from which the release agent 3 or the release agent 3 is produced can be contained in the glass, the release agent 3 or the release agent 3 is produced as the release agent introduction material 50. A glass plate containing various material components may be used.
For example, the release agent introduction material 50 may be composed of a release agent 3 or a coating film made of a dispersion liquid in which the material component in which the release agent 3 is produced is dispersed.

When the release agent 3 is introduced from the release agent introduction material 50 into the void portion 5, 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 that time, when the thickness of the film body upper layer 20B in the film body 21 exceeds t2, the upper part of the film body upper layer 2B and the gap 5 is removed until the thickness of the film body upper layer 2B reaches t2. It will be processed. It is more preferable that this removal process includes at least a mirror polishing finish process.
When the removal process is performed, a surface 2a lower than the surface 20a is formed on the upper portion of the upper layer portion 2B of the film body. In this way, the film body 2 in which the release agent 3 is introduced into the gap 5 is manufactured.
For example, when the release agent introduction material 50 is composed of a member movable 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 portion 2B in the membrane body 21 exceeds t2, after the release agent introduction material 50 is moved, the membrane body upper layer portion 2B is reached until the thickness of the membrane body upper layer portion 2B reaches t2. The upper part of 20B and the gap 5 is removed. More preferably, this removal process includes a mirror polishing finish process.
However, if the surface accuracy required for the lower mold 10A can be obtained without mirror polishing the surface 20a of the upper layer portion 20B of the film body, the surface 20a is formed in advance at the same height as the surface 2a.

In this way, as shown in FIG. 2, the release film 4 is formed on the molding surface 1a of the base material 1A. As a result, the lower mold 10A is manufactured.
The upper mold 10B is manufactured in the same manner as described above except that the base material 1B is prepared in place of the base material 1A and the release film 4 is formed on the molding surface 1b of the base material 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 molding mold assembly 10 is assembled so that the molding material G is arranged inside.
After that, the molding mold assembly 10 is sandwiched by the heating plates 11A and 11B arranged in the dust-proof processing chamber. The heating plate 11A supports the flange portion 10d of the lower mold 10A from below. The heating plate 11B abuts on the flange portion 10f of the upper die 10B from above. The heating plate 11B can pressurize the upper mold 10B toward the lower mold 10A by a press mechanism (not shown).
Heaters 12 are arranged inside the heating plates 11A and 11B, respectively. As the heater 12, for example, a ceramic cartridge heater may be used.
The heater 12 heats the heating plates 11A and 11B. The heater 12 continues heating until the temperatures of the mold surfaces 10a and 10b of the lower mold 10A and the upper mold 10B reach the molding temperature due to heat conduction from the heating plates 11A and 11B. The heater 12 keeps 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 in a softened state in which it is easily deformed, for example, a temperature equal to or higher than the yield point.

The temperature of the molding material G is raised 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 temperature of the entire molding material G reaches a temperature equal to or 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 press molding, each release film 4 constituting the mold surfaces 10a and 10b comes into contact with the molding material G in a state of being heated to the molding temperature. The release agent 3 is exposed in the opening 2c of the surface 2a of the upper layer portion 2B of the film body in each release film 4. Since the mold release agent 3 is contained in the upper layer portion 2B of the film body in a state where it can be moved 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 from the opening 2c between the surface 2a and the molding material G by melting or volatilizing at the molding temperature. However, since the molding material G is pressurized between the respective surfaces 2a of the molding surfaces 1a and 1b, the minimum layer between the surface 2a and the surface of the molding material G is thinned according to the pressing force. Only a limited release agent 3 intervenes, and the remaining release agent 3 is confined in the void portion 5.

When the molding material G is pressed into a shape having a predetermined lens thickness, the pressing mechanism is stopped. When the deformation of the pressed molding material G becomes stable, the heating of the heating plates 11A and 11B is stopped. As a result, heat dissipation cooling of the molding mold assembly 10 is started. The shapes of the mold surfaces 10a and 10b are transferred to the molding material G in the molding mold assembly 10, and a molded product by press molding is formed.
When a cooling plate for cooling the molding mold assembly 10 is provided in the molding chamber, the molding mold assembly 10 is moved to the cooling plate after the holding of the heating plates 11A and 11B is released. , The molding mold assembly 10 is cooled. The components of the release agent 3 that are melted by the molding temperature are solidified by being cooled below their respective melting points.
When the molded product is cooled to a temperature at which it can be removed from the mold, the molded product is removed from the molding mold assembly 10. At this time, the lower mold 10A and the upper mold 10B have the mold release performance of the material of the film body 2 in the mold release film 4 and the mold release performance of the mold release agent 3 interposed between the surface 2a and the molded product. , Combined with the smooth demolding. In this way, a molded product having the outer shape of the optical element is manufactured.
Since the mold release agent 3 that did not move to the outside of the void 5 during molding is solidified inside the void 5, it 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, if necessary.
In this way, the 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 void portion 5 is surfaced in one molding. As a result of moving to 2a, for example, a part of the release agent 3 is consumed by volatilizing or adhering to the molding material G. 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 smaller than that of an organic material having a lower melting point.
As described above, a part of the mold release agent 3 is consumed in one molding, but when the next molding is performed, the mold release agent 3 remaining in the gap 5 is surfaced in the same manner as described above. Move to 2a. Therefore, the release performance by the release agent 3 is maintained while the release agent 3 in the gap portion 5 of the upper layer portion 2B of the film body remains. Therefore, according to the lower mold 10A and the upper mold 10B of the present embodiment, the mold release performance is unlikely to deteriorate even if high-temperature molding is repeated.

On the other hand, for example, when a conventionally known organic mold release agent is applied to the surface of a molding surface of a molding mold having no voids 5, the organic mold release agent is molded once. Almost all is consumed by. Even if some of the organic release agents remain, 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 denatured during molding. Therefore, even if the organic mold release agent remains, the mold release performance at the time of application cannot be obtained, but rather it tends to cause fusion. Therefore, the organic mold release agent or the derivative of the organic mold release agent remaining on the surface of the molding mold needs to be cleaned after each molding.
According to such a conventional optical molding mold and molding method, it is difficult to perform good molding a plurality of times in succession by applying the release agent once. Therefore, it is necessary to repeat the application of the organic mold release agent and the molding after molding every time the molding is performed, so that it takes a lot of time to prepare for molding and to maintain the molding mold.
Further, since the organic mold release agent adhered to the molding surface in the modified state cannot be easily cleaned, the fusion of glass is likely to be induced from the fixed portion of the organic mold release agent when the molding is repeated. Therefore, the mold life is also shortened.
The above has been described with an example of the case where an organic release agent is used for molding, but even when an inorganic material that is difficult to be modified at the molding temperature is used as the release agent, the release film does not have voids. 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 portion 5 is formed inside a metal or alloy containing a noble metal, the gap portion 5 is formed even when the release agent 3 is moved to the outside. Remains uncrushed.
Therefore, when the amount of the release agent 3 contained in the upper layer portion 2B of the film body is reduced due to repeated molding, a step of replenishing the gap portion 5 with a new release agent 3 may be performed. In the step of replenishing the release agent 3, the method used for introducing the release agent 3 into the gap 5 at the time of manufacturing the release film 4 is used.
As described above, when the step of replenishing the release agent 3 is added in the above-mentioned manufacturing method of the optical element, the release film 4 of the lower mold 10A and the upper mold 10B can be used for a longer period of time. Since the membrane body 2 can be reused even when the release agent 3 is consumed, the lower mold 10A and the upper mold 10B are compared with the case where the release membrane 4 is reformed when the release agent 3 is consumed. Running costs are reduced.

[Second Embodiment]
A method for manufacturing an optical element molding mold according to a second embodiment of the present invention will be described.
11 to 13 are process explanatory views of a method for manufacturing an optical element molding mold according to a second embodiment of the present invention.

The method for producing an optical element molding mold of the present embodiment is used for producing a mold release film 4 similar to that of the first embodiment. In the following, an example of manufacturing the lower mold 10A will be described focusing on the points different from the first embodiment.

First, in the present embodiment, the base material 1A is prepared in the same manner as in the first embodiment.
After this, the release film 4 is formed on the molding surface 1a. In the present embodiment, in order to form the release film 4, the base film is formed, the base film is formed, the gap portion 5 is formed in the base film, and the gap portion 5 is formed. Introducing the release agent 3 includes.
As shown in FIG. 11, first, the undercoat film 30 is formed on the molding surface 1a. In the present embodiment, the base film 30 constitutes the film body base layer portion 2A. Therefore, 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 body base layer portion 2A can be used. However, in the present embodiment, since the base film 30 does not form the gap portion 5, it is not necessary to include the removing material for forming the gap portion 5 as included in the base film 20.
As the film forming method of the base film 30, an appropriate film forming method as exemplified as the film forming method of the base film 20 in the first embodiment is used.

After that, as shown in FIG. 12, the base film 33 is formed on the surface 30a of the base film 30. The base film 33 is used to form the upper layer portion 2B of the film body and the void portion 5.
The base film 33 has a film body material 32 and a removal material 35.
The film body material 32 is made of a metal or alloy containing a noble metal element. As the film body material 32, the same material as the film body upper layer portion 2B is used. The film body material 32 may be different from or the same as the material of the base film 30 as long as it has high adhesion to the base film 30.
It is more preferable that the distribution of the film body material 32 corresponds to the upper layer portion 2B of the film body to be formed. However, the distribution of the film body material 32 may change with the movement of the removal material 35 in 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 void portion 5 to be formed. However, the distribution of the removal material 35 will be described later by moving the removal material from the initial distribution state in the removal process of the removal material 35 described later, similarly to the removal material in the base film 20 in the first embodiment. The distribution may be such that the shape of the gap portion 5 is obtained.

As the film forming method of the base film 33, an appropriate film forming method similar to that of the base film 20 is selected depending on 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 an allowable range as the mold surface without requiring a finishing step such as mirror polishing, the film thickness t5 of the base film 33 is the upper layer of the film body. The layer thickness is t2, which is the same as that of part 2B.
When a finishing step such as mirror polishing is required after the film formation because the unevenness of the surface 32a of the base film 33 is within the allowable range as the mold surface, the film thickness t5 of the base film 33 is the film thickness upper layer 2B of the film body. The thickness is the sum of the layer thickness t2 and the finishing allowance.

After the base film 33 is formed, the gap portion 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, so that the gap portion 5 is formed as shown in FIG.
As a method for removing the removal material 35, for example, a method similar to the method for removing the removal material for the base film 20 in the first embodiment may be used.
Further, in the case of the present embodiment, even if the removal material 35 is completely removed, the void portion 5 is formed only in the range of the film thickness of the base film 33. Therefore, as the removing material 35, for example, a material that can be completely removed from the base film 33 by vaporizing at a molding temperature or higher may be used.
When all the removing material 35 is removed from the base film 33, the type of the removing 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 on 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, as an example, a case where almost all of the removing material 35 is removed from the base film 33 will be described.

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

In the film body 31, the upper layer portion 30B of the film body has a nanoporous structure composed of the film body material 32 by removing the removal material 35 from the material of the base film 33.

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

As described above, according to the method for manufacturing the optical element molding mold of the present embodiment, the lower mold 10A and the upper mold 10B provided with the same release film 4 as in the first embodiment can be manufactured. It has the same function as that of the first embodiment.
Further, in the present embodiment, the release film 4 is manufactured starting from a two-layer structure of the base film 30 and the base film 33.
Therefore, since the removal material 35 only needs 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.
Further, since substantially all of the removing material 35 is removed from the base film 33, the gap portion 5 extending over substantially the entire 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 can be completely removed from the base film 33 so that the removal material 35 is not included in the entire release film 4. Therefore, in the present embodiment, even a material whose film strength of the release film 4 decreases when it remains on the release film 4 can be used as the removal material 35.

[Third Embodiment]
The release film and the optical element molding mold of the third embodiment of the present invention will be described.
FIG. 14 is a schematic cross-sectional view showing the structure 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 in place of the film body 2 of 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, the points different from those of the first embodiment will be mainly described.

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

The film body 42 having such a structure may be manufactured, for example, by extending the formation region of the gap portion 5 in the film body 2 in the first embodiment in the film thickness direction to the molding surface 1a (1b). ..
For example, in the film body 42, the same base film 33 as in the second embodiment is formed on the molding surface 1a (1b) with a film thickness t1, and then the removal material 35 is formed in the same manner as in the second embodiment. May be manufactured 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 provided with 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. It has the same operation as that of the first embodiment.
Further, in the present embodiment, since the release agent 3 is dispersed over the entire film thickness direction of the release film 44, more release agents 3 are released as compared with the first embodiment. It can be contained in 44. Therefore, the number of shots capable of good molding in the lower mold 10A and the upper mold 10B is improved.

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

In the description of each of the above embodiments, an example in which the material to be removed 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 fibrous shape, a rod shape, or a plate shape.

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

[Example 1]
The first embodiment is an embodiment relating to the first embodiment.
First, a base material 1A manufactured of a cemented carbide having the shape of the lower mold 10A excluding the release film 4 was prepared. The molded surface 1a of the base material 1A was mirror-polished by mechanical polishing.
After that, a base film 20 (t3 = 3 (μm)) composed of platinum and rhenium dispersed in platinum was formed on the molding surface 1a of the base material 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 heat-treated at 400 ° C. for 15 minutes in an electric furnace in an atmospheric atmosphere in order to oxidize rhenium. As a result, a film body 21 having a nanoporous structure was formed in the upper layer (see FIG. 7).
A 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.

The process of forming the film body 21 by the heat treatment will be briefly described. Rhenium oxide is a substance that has a melting point of 360 ° C and sublimates. Therefore, when the 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 the rhenium inside the base film 20 is oxidized by oxygen entering from the void portion 5 formed by sublimation of rhenium oxide, the void portion 5 extends to the inside of the base film 20. It is considered that the film body 21 was formed in this way.
The depth at which the void portion 5 is formed is determined by heat treatment conditions such as heating temperature and heating time.

After that, 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, the release agent introduction material 50 was placed on the surface 20a of the membrane body 21 (see FIG. 10), and heat treatment was performed at 600 ° C. for 60 minutes in an electric furnace in a nitrogen atmosphere.
As a result, zinc contained in the release agent introduction material 50 was introduced into the gap 5 through the opening 20c, and the lower mold 10A having the release film 4 was produced.
In the same manner, observation samples of the release membrane 4 and the lower mold 10A were prepared. The release film 4 in the observation sample was processed by FIB (focused ion beam), and the processed 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 in the range of 0.5 μm in depth from the surface 20a of the base film 20. Therefore, it is considered that zinc was introduced into the gap 5 having a depth of 0.5 μm.

In the same manner, the upper mold 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 620 ° C. to produce molding of the shape of an optical element.
During the molding of 100 shots, 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 interposing between the molding material G and the mold release film 4 through the opening 2c of the mold release film 4.

[Example 2]
The second embodiment is an embodiment 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.
After that, a base film 20 (t3 = 2 (μm)) composed of platinum and molybdenum dispersed in platinum was formed on the molding surface 1a of the base material 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, like rhenium oxides, sublimate.
In order to oxidize molybdenum, the base material 1A on which the base film 20 was formed was oxidized in an electric furnace in an atmospheric atmosphere. The electric furnace is provided with a tubular electric furnace having a length of 300 mm surrounding the quartz tube in the center of a quartz tube having a diameter of 50 mm and a length of 1000 mm in the longitudinal direction. Atmosphere is introduced from one of the quartz tubes and discharged from the other. A xenon excimer lamp is provided on the quartz tube on the side where the atmosphere is introduced so that the inside of the quartz tube can be irradiated. With the xenon excimer lamp turned on and the inside of the quartz tube illuminated, heating was performed at 550 ° C. for 30 minutes in an electric furnace. The xenon excimer lamp was irradiated by photodecomposing oxygen in the atmosphere inside the quartz tube to generate active oxygen and ozone, which are transported by the airflow near the surface of the base film 20 to oxidize molybdenum. This is to promote.
After that, 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 was formed in the upper layer (see FIG. 7).

After that, tin serving as the release agent 3 was deposited on the surface 20a of the film body 21. The tin-deposited layer was used as the release agent introduction material 50 in this example (see FIG. 10).
The tin-deposited film body 21 was heat-treated at 350 ° C. for 60 minutes in an electric furnace having a nitrogen atmosphere.
As a result, tin was melted and introduced into the void 5 through the opening 20c. After that, the surface of the film body 21 was mirror-polished to produce a lower mold 10A having the release film 4.

In the same manner, the upper mold 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 in the shape of an optical element.
During the molding of 100 shots, 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 interposing between the molding material G and the mold release film 4 through the opening 2c of the mold release film 4.

[Example 3]
Example 3 is an example relating to the second embodiment.
First, a base material 1A manufactured of a cemented carbide having the shape of the lower mold 10A excluding the release film 4 was prepared.
After that, a base film 30 (t4 = 1 (μm)) made of gold was formed on the molding surface 1a of the base material 1A by vapor deposition (see FIG. 11).
After that, a base film 33 having a film thickness of t5 was applied to the surface 30a of the base film 30 (see FIG. 12). Specifically, as the base film 33, a gold nanoparticle dispersion paste to which polyvinyl alcohol was added was used. This gold nanoparticle dispersion paste was produced by adding polyvinyl alcohol to a gold nanoparticle solution obtained by reducing gold chloride 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 atmospheric atmosphere in order to burn off polyvinyl alcohol. As a result, polyvinyl alcohol was burned off, and the remaining gold particles formed the upper layer portion 30B of the film body having a nanoporous structure (see FIG. 13). The gold particles constituting the bottom surface 30b of the upper layer portion 30B of the film body were in close contact with and integrated with the surface 30a of the base film 30. As a result, the film body 31 having the film body base layer portion 2A (undercoat film 30) and the film body upper layer portion 30B was formed.

After that, a nano-dispersion solution in which antimony pentoxide, which is the release agent 3, was dispersed in a solvent composed of water and triethanolamine was applied to the surface 32a of the membrane body 31. The coating film of the nanodisperse of antimony pentoxide was used as the release agent introduction material 50 in this example (see FIG. 10).
The membrane body 31 coated with the nanodisperse of antimony pentoxide was heat-treated at 350 ° C. for 60 minutes in an electric furnace in an air atmosphere. As a result, antimony pentoxide was absorbed inside the void 5.
After that, the surface 32a of the film body 31 in which antimony pentoxide was absorbed was mirror-polished to produce a lower mold 10A having a release film 4. As the polishing liquid used for mirror polishing, an alumina-based abrasive dispersion liquid was used.

In the same manner, the upper mold 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 product in the shape of an optical element.
During the molding of 300 shots, seizure of the molded product did not occur. 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 interposing between the molding material G and the mold release film 4 through the opening 2c of the mold release film 4. ..

[Comparison example]
Molds for Comparative Examples were manufactured for comparison with Examples 1-3. In the molding mold of Comparative Example, a release film made of platinum was formed in place of the release film 4 of the lower mold 10A and the upper mold 10B of Example 1. In the method for manufacturing an optical element using the molding mold of the comparative example, an organic mold release agent obtained by diluting glycerin with alcohol is applied to the surface of the mold release film under the same molding conditions as in Example 1. The optical element was molded.
When 30 shots of molding were performed, seizure of the molded product occurred, and cloudiness also occurred on the surface of the molded product. Therefore, the life of the molding die was significantly shorter than that of Examples 1 to 3.
It is considered that this is because the organic mold release agent component decomposed at the molding temperature adheres to the mold release film and the surface of the molded product.

Although the preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples. Configurations can be added, omitted, replaced, and other modifications without departing from the spirit of the present invention.
Further, the present invention is not limited by the above description, but 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 release Molds 4, 44 Release film 5 Voids 10a, 10b Mold surface 10A Lower mold (mold for optical element molding)
10B upper mold (mold for forming optical elements)
0, 33 Base film 30 Under film 32 Membrane body material 35 Removal material 50 Release agent introduction material G Molding material

Claims (10)

A mold release film used for an optical element molding mold that forms an optical element by pressing a glass material as a molding material.
A film body formed on the surface of the optical element forming mold, made of a metal or alloy containing a noble metal element, and not melted at a molding temperature.
At the forming temperature, and a release agent dispersed inside the film body in a movable state on the surface in contact with the molding material in the film body,
A release membrane. The release film according to claim 1, wherein the release agent is dispersed from the surface to a range less than the thickness of the film body. The release film according to claim 1 or 2, wherein the release agent has a melting point lower than the molding temperature. The release film according to claim 3, wherein the release agent is an inorganic material. The release film according to any one of claims 1 to 4, wherein the film body has a nanoporous structure in a range in which the release agent is dispersed. An optical element molding mold comprising the release film according to any one of claims 1 to 5. To prepare a base material that constitutes at least a part of the molding die body and has a molding surface formed to be transferred to the glass material .
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 is formed on the surface of the base material.
By removing at least a part of the removal material from the base film, a gap portion communicating from the inside of the base film to the surface of the base film is formed.
Introducing a mold release agent into the void and
A method for manufacturing a mold for forming an optical element, including. To prepare a base material that constitutes at least a part of the molding die body and has a molding surface formed to be transferred to the glass material .
To form a base film made of a metal or alloy containing a noble metal element on the surface of the base material,
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 is formed on the surface of the base film.
By removing at least a part of the removal material from the base film, a gap portion communicating from the inside of the base film to the surface of the base film is formed.
Introducing a mold release agent into the void and
A method for manufacturing a mold for forming an optical element, including. To prepare a base material that constitutes at least a part of the molding die body and has a molding surface formed to be transferred to the glass material .
A base film having a metal or alloy containing a noble metal element is formed on the surface of the base material.
To form a nanoporous structure in the base film, which has a minute opening on the surface of the base film and an air gap extends from the opening to the inside of the base film.
Introducing a mold release agent into the void and
A method for manufacturing a mold for forming an optical element, including. Molding an optical element by molding the molding material using the mold for molding an optical element provided with the release film according to any one of claims 1 to 5.
After molding a plurality of the optical elements, the release agent is replenished inside the release film.
A method of manufacturing an optical element, which repeats the above steps.

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