JP2011190118A - Mold for molding optical element, optical element and method for producing the optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for molding an optical element where reactivity with an optical element material is low, where the coefficient of friction between the optical element material and the surface layer of the mold for molding the optical element is lowered, where adhesion between the base material of the mold for molding the optical element and the surface layer is excellent and where releasability and durability are excellent, a method for producing the optical element using the mold for molding the optical element and the optical element obtained by the producing method. <P>SOLUTION: The mold for molding the optical element includes the base material and the surface layer which includes diamond-like carbon containing Si and O and the like. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical element molding die, an optical element manufacturing method using the optical element molding die, and an optical element obtained by the manufacturing method.

  A direct press molding method is known as a method for manufacturing an optical glass lens that is an optical element. In the direct press molding method, a glass lump that is an optical element material is heated on a mold for optical element molding finished to a desired surface quality and surface accuracy, or a glass lump that has been pre-heated is heated. In this method, an optical glass lens is manufactured by press molding.

  The optical element molding die used for the direct pressing method is not only capable of preventing occurrence of cracks in the optical element, but also reactive with the optical element material from the viewpoint of durability and releasability. Low moldability, good releasability between the surface of the optical element molding die and the optical element material, excellent adhesion between the substrate of the optical element molding die and the surface layer, press of the optical element molding die It is required that the friction coefficient of the surface is small and that the optical element can be produced in a short time.

  So far, in press molding of optical glass elements, by using a press molding mold for optical glass elements formed by forming a diamond film or a diamond-like carbon film on a base material, lead oxide glass lenses are excellent. A technique capable of press forming has been proposed (for example, see Patent Document 1).

  Further, by using a molding die in which a hydrogenated amorphous carbon film is coated via a diamond film at a portion in contact with glass during press molding, the reaction of lead oxide is further suppressed as compared with Patent Document 1. A possible technique has been proposed (see, for example, Patent Document 2).

  Also, a technology that achieves both mold releasability and durability by using an optical element molding die that has a large amount of graphite on the interface side of the optical element molding base material and a small amount of graphite on the surface side (release surface side). Has been proposed (see, for example, Patent Document 3).

  In addition, by using an optical element molding die with less graphite on the base material interface side and more graphite from the interface with the base material to the surface (release surface), both mold release and durability are achieved. A technique has been proposed (see, for example, Patent Document 4).

  In addition, a technique has been proposed in which the formation of a can (crack) can be significantly suppressed by forming a diamond-like carbon release film on a base material (see, for example, Non-Patent Document 1).

  In addition, by coating the molding surface of the base material with an amorphous hydrogen-containing Si—C (aC: H: Si) film, it can withstand long-term continuous molding and can sufficiently secure the performance of the molded product. A mold has been proposed (see, for example, Patent Document 5). This proposal states that the Si content in the aC: H: Si film needs to be 10 mol% to 23 mol%, and the thickness of the aC: H: Si film needs to be 50 nm to 150 nm. Has been. This is considered to be imparting flexibility (buffering property) and lubricity by containing Si in the film.

In these prior art optical element molding molds, a glass containing a highly reactive material (for example, TiO ₂ , Nb ₂ O ₅ , WO ₃ , Bi ₂ O _3, etc.) is used as the optical element material. However, there is a problem that fusion occurs at the time of molding or a problem that a can (crack) is generated when a thin lens is molded, and durability and releasability are insufficient. In addition, it has not yet been obtained what has sufficient durability and releasability and is excellent in adhesion between the base material of the optical element molding die and the surface layer.
Therefore, at present, there is a demand for rapid development of an optical element molding die that is excellent in durability and releasability, and also excellent in adhesion between the optical element molding die base material and the surface layer. is there.

Japanese Examined Patent Publication No. 02-047411 Japanese Patent Laid-Open No. 02-080330 Japanese Patent Laid-Open No. 08-301625 Japanese Patent Application Laid-Open No. 09-12320 JP 09-194216 A

Proc. Of the XX ICG in Kyoto (2004) “GLASS PREFORM FORMATION AND CRACK FORMATION MECHANISM IN MOLDING PROCESS” T. Igari et al. HOYA Corporation

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention has low reactivity with the optical element material, and can reduce the friction coefficient between the optical element material and the surface layer of the optical element molding die. An optical element molding die having excellent adhesion and excellent releasability and durability, a method of manufacturing an optical element using the optical element molding die, and an optical element obtained by the manufacturing method are provided. For the purpose.

  In order to solve the above-mentioned problems, the present inventors have made extensive studies and as a result, obtained the following findings. That is, when the surface layer contains diamond-like carbon containing Si and O, the reactivity with the optical element material is low, and the friction coefficient between the optical element material and the surface layer of the optical element molding die is lowered. This is a new finding that an optical element molding die having excellent adhesion between the base material of the optical element molding die and the surface layer and excellent in releasability and durability can be obtained.

Means for solving the problems are as follows. That is,
<1> It has a base material and a surface layer,
The optical element molding die, wherein the surface layer includes diamond-like carbon containing Si and O.
<2> A method for producing an optical element, wherein an optical element material is molded using the optical element molding die according to <1>.
In the optical element manufacturing method, since the optical element molding die is used, fusion of the optical element material to the optical element molding die can be suppressed, and transfer to the obtained optical element can be suppressed. Therefore, defects in the optical element can be suppressed.
<3> An optical element manufactured by the method for manufacturing an optical element according to <2>.

  According to the present invention, conventional problems can be solved, the reactivity with the optical element material is low, the coefficient of friction between the optical element material and the surface layer of the optical element molding die can be lowered, and the optical element molding die An optical element molding die having excellent adhesion between the base material and the surface layer, and having excellent releasability and durability, an optical element manufacturing method using the optical element molding die, and the manufacturing method The resulting optical element can be provided.

FIG. 1 is a schematic diagram of plasma CVD. FIG. 2 is an explanatory view before press molding. FIG. 3 is an explanatory diagram during press molding. FIG. 4 is a microscopic image of the surface of the optical element molding die 1 after 100 shot molding of Example 2-1. FIG. 5 is a microscopic image of the surface of the optical element molding die 2 after 100 shot molding of Example 2-2. FIG. 6 is a microscopic image of the surface of the optical element molding die 2 after 100 shot molding of Example 2-3. FIG. 7 is a microscopic image of the surface of the optical element molding die 2 after 100 shot molding of Example 2-4. FIG. 8 is a microscopic image of the surface of the optical element molding die 3 after 100 shot molding of Example 2-5. FIG. 9 is a microscopic image of the surface of the optical element molding die 4 after 100 shot molding of Example 2-6. FIG. 10 is a microscopic image of the surface of the optical element molding die 5 after 100 shot molding of Example 2-7. FIG. 11 is a microscopic image of the surface of the optical element molding die 6 after 100 shot molding of Example 2-8. FIG. 12 is a microscopic image of the surface of the optical element molding die 7 after 100 shot molding of Comparative Example 2-1. FIG. 13 is a microscopic image of the surface of the optical element molding die 7 after 100 shot molding of Comparative Example 2-2. FIG. 14 is a microscopic image of the surface of the optical element molding die 7 after 100 shot molding of Comparative Example 2-3. FIG. 15 is a microscopic image of the surface of the optical element molding die 8 after 100 shot molding in Comparative Example 2-4.

(Optical element molding mold)
The optical mold of the present invention has at least a base material and a surface layer, and has other configurations as necessary.

<Base material>
There is no restriction | limiting in particular as a material of the said base material, a shape, and a magnitude | size, According to the objective, it can select suitably.
Examples of the material of the base material include cemented carbide (tungsten carbide (WC), tungsten carbide-cobalt (WC-Co) alloy), silicon carbide (SiC), boron nitride-containing silicon nitride, cermet, zirconia (ZrO). ₂ ), silicon nitride (Si ₃ N ₄ ), titanium carbide (TiC), mixed metal material, 13Cr martensite steel, silicon (Si), titanium oxide (TiO ₂ ), stainless steel, and the like.
Among these, cemented carbide and silicon carbide are advantageous in that they are excellent in adhesion and workability.
The shape and size of the substrate can be appropriately selected depending on the shape and size of the target optical element.

The surface of the base material is preferably subjected to pretreatment such as mirror polishing and washing before forming a surface layer described later.
There is no restriction | limiting in particular as methods of pre-processing, such as said mirror polishing and washing | cleaning, A well-known method can be selected suitably.
Furthermore, the substrate may be cleaned by reverse sputtering, ion irradiation, or the like.

<Surface layer>
The surface layer contains diamond-like carbon containing at least Si and O, and further contains other components as necessary.
The surface layer is preferably made of only diamond-like carbon containing Si and O.

-Diamond-like carbon-
The diamond-like carbon (hereinafter sometimes referred to as “DLC”) refers to one having a diamond-like structure and a graphite-like structure.
There is no restriction | limiting in particular as said diamond-like carbon, According to the objective, it can select suitably, For example, hydrogenated amorphous carbon, i-carbon, hard carbon etc. are mentioned.

  Examples of the analysis method for the diamond-like carbon include Raman spectroscopy.

-C content-
There is no restriction | limiting in particular as content of C in the said surface layer, Although it can select suitably according to the objective, Content of C with respect to the total content (Si + O + C, the number of atoms) of Si, O, and C The ratio (composition ratio) {C / (Si + O + C)} of (number of atoms) is preferably 0.3 or more, more preferably 0.4 or more, and particularly preferably 0.5 or more. If {C / (Si + O + C)} is less than 0.3, the effect of releasability may be lowered. On the other hand, when the content of C in the surface layer is within the particularly preferred range, it is advantageous in that there are effects of low reactivity and low friction, and surface oxidation is also suppressed.

-Si content-
There is no restriction | limiting in particular as content of Si in the said surface layer, Although it can select suitably according to the objective, Content of Si with respect to the total content (Si + O + C, the number of atoms) of Si, O, and C The ratio (composition ratio) {Si / (Si + O + C)} of (number of atoms) is preferably 0.01 or more, more preferably 0.03 or more, and particularly preferably 0.05 or more. If {Si / (Si + O + C)} is less than 0.01, the effect of reducing friction may be reduced. On the other hand, when the Si content in the surface layer is within the particularly preferred range, it is advantageous in that there are effects of low reactivity and low friction, and surface oxidation is also suppressed.

-O content-
There is no restriction | limiting in particular as content of O in the said surface layer, Although it can select suitably according to the objective, Content of O with respect to the total content (Si + O + C, the number of atoms) of Si, O, and C The ratio (composition ratio) {O / (Si + O + C)} of (number of atoms) is preferably 0.005 or more and 0.2 or less, more preferably 0.01 or more and 0.15 or less, and 0.05 or more and 0.1 or less. Is particularly preferred. When {O / (Si + O + C)} is less than 0.05, the effect of low reactivity may be diminished, and when it exceeds 0.2, productivity of oxygen ashing may be deteriorated. On the other hand, when the content of O in the surface layer is within the particularly preferred range, it is advantageous in that there are effects of low reactivity and low friction, and surface oxidation is also suppressed.

  The contents of Si, O, and C in the surface layer can be determined by, for example, XPS (X-ray Photoelectron Spectroscopy) analysis and Auger electron spectroscopy analysis.

-Thickness-
There is no restriction | limiting in particular as thickness of the said surface layer, Although it can select suitably according to the objective, 2 nm-500 nm are preferable, 3 nm-400 nm are more preferable, and 5 nm-300 nm are especially preferable. If the thickness of the surface layer is less than 2 nm, a film may not be uniformly formed on the entire surface. If the thickness is 300 nm or more, productivity is significantly deteriorated in a peeling step by oxygen ashing for film regeneration. On the other hand, when the thickness of the surface layer is within the particularly preferable range, it is advantageous in that a film is formed on the entire surface and the adhesion is strong.
The thickness of the surface layer can be measured, for example, by ellipsometry.

-Friction coefficient-
There is no restriction | limiting in particular as a friction coefficient of the said surface layer, Although it can select suitably according to the objective, 0.01-0.08 are preferable, 0.02-0.07 are more preferable, 0.04 -0.06 is particularly preferred. If the friction coefficient of the surface layer is less than 0.01, the molding surface of the mold may not be uniformly transferred to the lens, and if it exceeds 0.1, a can may occur with the frequency of use. On the other hand, when the coefficient of friction of the surface layer is within the particularly preferable range, it is advantageous in terms of stability of the lens shape and suppression of can.
The coefficient of friction of the surface layer can be measured, for example, by making a SUS ball move linearly by 10 mm at a load of 100 gf and 1 mm / sec using a ball-on-disk device.

  There is no restriction | limiting in particular as a formation method of the said surface layer, According to the objective, it can select suitably, For example, plasma CVD (chemical vapor deposition), sputtering, ion plating, ion beam evaporation etc. are mentioned.

  In the formation of the surface layer by the plasma CVD, the gas for supplying carbon (C) is not particularly limited and can be appropriately selected according to the purpose. For example, alkane such as methane, ethane, and propane, ethylene, Alkenes such as propylene, alkadienes such as pentadiene and butadiene, alkynes such as acetylene and methylacetylene, aromatic hydrocarbons such as benzene, toluene and xylene, cycloalkanes such as cyclopropane and cyclohexane, cycloalkenes such as cyclopentene and cyclohexene, etc. Can be mentioned. The said gas may be used individually by 1 type, and may use 2 or more types together.

Further, in the formation of the surface layer by the plasma CVD, a gas for supplying silicon (Si) and oxygen (O) is not particularly limited and can be appropriately selected according to the purpose. For example, tetramethoxysilane ( TMOS: Si (OCH ₃ ) ₄ ), tetraethoxysilane (TEOS: Si (OC ₂ H ₅ ) ₄ , mixed gas of tetramethylsilane (TMS: Si (CH ₃ ) ₄ ) and oxygen (O ₂ ), four Examples thereof include a mixed gas of silicon chloride (SiCl ₄ ) and oxygen (O ₂ ), etc. These gases may be used alone or in combination of two or more.

  There is no restriction | limiting in particular as a flow volume and pressure of gas in formation of the surface layer by the said plasma CVD, According to the objective, it can select suitably.

There is no restriction | limiting in particular as a frequency in the said plasma CVD, According to the objective, it can select suitably, For example, a high frequency (13.56MHz) is mentioned.
There is no restriction | limiting in particular as said high frequency output, Although it can select suitably according to the objective, 1.0 kW-5.0 kW are preferable, 1.5 kW-4.0 kW are more preferable, 1.8 kW-3 0.0 kW is particularly preferred. When the output of the high frequency is less than 1.0 kW, the film may be peeled off with the frequency of use, and when it exceeds 5.0 kW, the mold becomes high temperature during film formation and the hardness of the film may decrease. is there. On the other hand, when the output of the high frequency is within the particularly preferable range, it is preferable in that the hardness of the surface layer is excellent.

<Other configurations>
There is no restriction | limiting in particular as said other structure unless the effect of this invention is impaired, According to the objective, it can select suitably, For example, an intermediate | middle layer is mentioned.

-Intermediate layer-
The intermediate layer is formed between the base material and the surface layer.
By forming the intermediate layer, deformation of the base material can be prevented.
There is no restriction | limiting in particular as a material and thickness of the said intermediate | middle layer, According to the objective, it can select suitably.
Examples of the material include TiN, TaN, ZrN, HfN, AlN, TiC, TaC, ZrC, HfC, TiAlN, TiCN, TaCN, ZrCN, HfCN, SiC, SiN, diamond, and the like.
Examples of the thickness of the intermediate layer include 2 μm.
There is no restriction | limiting in particular as a formation method of the said intermediate | middle layer, According to the objective, it can select suitably, For example, sputtering, ion plating, CVD etc. are mentioned.

(Optical element and manufacturing method thereof)
The optical element of the present invention is manufactured by the method for manufacturing an optical element of the present invention.
In the method for producing an optical element of the present invention, an optical element material is molded using the optical element molding die of the present invention.

-Optical element materials-
As the optical element material is not particularly limited and may be appropriately selected depending on the purpose, for example, glass containing glass containing TiO _2, the _Nb 2 _{O 5,} glass containing WO _3, Bi ₂ Examples thereof include glass containing O ₃ . The glass containing at least one of Ti, W, Nb, and Bi has high reactivity, but an optical element with few defects can be manufactured by using the optical element molding die of the present invention.

-Molding-
There is no restriction | limiting in particular as a method of shape | molding the said optical element material, According to the objective, it can select suitably, For example, press molding, injection molding, etc. are mentioned.
In the press molding, the optical element material lump may be heated and pressed on the optical element molding die, or the preheated lump of optical element material may be pressed.
The heating temperature, press load, and press time are not particularly limited and may be appropriately selected depending on the optical element material.

-Optical element-
There is no restriction | limiting in particular as a shape and a magnitude | size of the said optical element, According to the objective, it can select suitably.
Examples of the optical element include a lens and a prism.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Example 1-1)
<Manufacture of optical element molding die 1>
Cemented carbide (WC-Co) was used as a base material for the optical element molding die.
As the upper base material of the optical element molding die, one having a flat surface was used.
The lower mold base material for the optical element molding die used had a concave surface.

-Formation of surface layer-
A diamond-like carbon surface layer containing Si and O having a thickness of 10 nm was formed on the surfaces (pressed surfaces) of the upper mold substrate and the lower mold substrate by plasma CVD under the following conditions. The content of Si and O in the surface layer is Si: O: C = 0.50: 0.15: 0.35 as the composition ratio of Si, O, and C (Si: O: C). Thus, the methane (CH ₄ ) gas flow rate (5 sccm to 200 sccm) and the tetraethoxysilane (TEOS) gas flow rate (0.1 sccm to 5 sccm) were adjusted.
Plasma CVD conditions:
High frequency power supply ... 13.56MHz
High frequency output 2kW
Gas pressure: 4Pa
Methane (CH ₄ ) gas flow rate was adjusted at 5 sccm to 200 sccm.
Tetraethoxysilane (TEOS) gas flow rate was adjusted to 0.1 sccm to 5 sccm.
FIG. 1 shows a schematic diagram of plasma CVD. In FIG. 1, reference numeral 1 indicates gas, reference numerals 2 and 4 indicate high-frequency electrodes, reference numeral 3 indicates a base material, reference numeral 5 indicates a matching box, and reference numeral 6 indicates a high-frequency power source.

  As a result of analysis by Raman spectroscopy, diamond-like carbon was formed in the surface layer.

  When the contents of Si, O, and C in the surface layer were confirmed by XPS analysis, the composition ratio was Si: O: C = 0.50: 0.15: 0.35.

The friction coefficient of the surface layer was measured as follows and was 0.07.
-Measuring method of friction coefficient-
Using a ball-on-disk device, a SUS ball was linearly moved by 10 mm at a load of 100 gf and 1 mm / sec, and the friction coefficient was measured.

(Example 1-2)
<Manufacture of optical element molding die 2>
In the formation of the surface layer of Example 1-1, the composition ratio of Si, O, and C (Si: O: C) is set to be Si: O: C = 0.50: 0.15: 0.35. The optical element molding die 2 was manufactured in the same manner as in Example 1-1 except that Si: O: C = 0.18: 0.05: 0.77.

As a result of analysis by Raman spectroscopy in the same manner as in Example 1-1, diamond-like carbon was formed in the surface layer.
When the contents of Si, O, and C in the surface layer were confirmed by XPS analysis in the same manner as in Example 1-1, the composition ratio was Si: O: C = 0.18: 0.05: 0. .77.
The coefficient of friction of the surface layer was measured in the same manner as in Example 1-1, and it was 0.06.

(Example 1-3)
<Manufacture of optical element molding die 3>
In the formation of the surface layer of Example 1-1, the composition ratio of Si, O, and C (Si: O: C) is set to be Si: O: C = 0.50: 0.15: 0.35. The optical element molding die 3 was manufactured in the same manner as in Example 1-1 except that Si: O: C = 0.03: 0.01: 0.96.

As a result of analysis by Raman spectroscopy in the same manner as in Example 1-1, diamond-like carbon was formed in the surface layer.
When the contents of Si, O, and C in the surface layer were confirmed by XPS analysis in the same manner as in Example 1-1, the composition ratio was Si: O: C = 0.03: 0.01: 0. .96.
The coefficient of friction of the surface layer was measured in the same manner as in Example 1-1, and it was 0.05.

(Example 1-4)
<Manufacture of optical element molding die 4>
Optical element molding die 4 in the same manner as in Example 1-3, except that the surface layer thickness was set to 10 nm in the formation of the surface layer in Example 1-3. Manufactured.

As a result of analysis by Raman spectroscopy in the same manner as in Example 1-1, diamond-like carbon was formed in the surface layer.
When the contents of Si, O, and C in the surface layer were confirmed by XPS analysis in the same manner as in Example 1-1, the composition ratio was Si: O: C = 0.03: 0.01: 0. .96.
The coefficient of friction of the surface layer was measured in the same manner as in Example 1-1, and it was 0.05.

(Example 1-5)
<Manufacture of optical element molding die 5>
In the formation of the surface layer of Example 1-3, the optical element molding die 5 was the same as Example 1-3, except that the thickness of the surface layer was 10 nm, except that the thickness of the surface layer was 300 nm. Manufactured.

As a result of analysis by Raman spectroscopy in the same manner as in Example 1-1, diamond-like carbon was formed in the surface layer.
When the contents of Si, O, and C in the surface layer were confirmed by XPS analysis in the same manner as in Example 1-1, the composition ratio was Si: O: C = 0.03: 0.01: 0. .96.
The coefficient of friction of the surface layer was measured in the same manner as in Example 1-1, and it was 0.05.

(Example 1-6)
<Manufacture of optical element molding die 4>
In the formation of the surface layer of Example 1-1, the composition ratio of Si, O, and C (Si: O: C) is set to be Si: O: C = 0.50: 0.15: 0.35. The optical element molding die 6 was manufactured in the same manner as in Example 1-1 except that Si: O: C = 0.01: 0.005: 0.985.

As a result of analysis by Raman spectroscopy in the same manner as in Example 1-1, diamond-like carbon was formed in the surface layer.
When the contents of Si, O, and C in the surface layer were confirmed by XPS analysis in the same manner as in Example 1-1, the composition ratio was Si: O: C = 0.01: 0.005: 0. .985.
The coefficient of friction of the surface layer was measured in the same manner as in Example 1-1, and it was 0.05.

(Comparative Example 1-1)
<Manufacture of optical element molding die 7>
The base material similar to Example 1-1 was used for the base material of the optical element molding die.

-Formation of surface layer-
On the surface (press surface) of the upper mold substrate and the lower mold substrate, a diamond-like carbon surface layer containing no Si and O and having a thickness of 10 nm was formed by plasma CVD under the following conditions.
Plasma CVD conditions:
High frequency power supply ... 13.56MHz
High frequency output 2kW
Gas pressure: 4Pa
Methane (CH ₄ ) gas flow rate was adjusted at 5 sccm to 200 sccm.

As a result of analysis by Raman spectroscopy in the same manner as in Example 1-1, diamond-like carbon was formed in the surface layer.
When the contents of Si, O, and C in the surface layer were confirmed by XPS analysis in the same manner as in Example 1-1, the composition ratio was Si: O: C = 0: 0: 1.
The coefficient of friction of the surface layer was measured in the same manner as in Example 1-1, and it was 0.12.

(Comparative Example 1-2)
<Manufacture of optical element molding die 8>
The base material similar to Example 1-1 was used for the base material of the optical element molding die.

-Formation of surface layer-
A surface layer of diamond-like carbon containing Si and C having a thickness of 300 nm and not containing O is formed on the surface (press surface) of the upper mold substrate and the lower mold substrate by plasma CVD under the following conditions. Formed. The methane (CH ₄ ) gas flow rate is such that the content of Si and C in the surface layer is Si: C = 0.03: 0.97 as the composition ratio of Si and C (Si: C). (5 sccm to 200 sccm) and a tetramethylsilane (TMS) gas flow rate (0.1 sccm to 5 sccm).
Plasma CVD conditions:
High frequency power supply ... 13.56MHz
High frequency output 2kW
Gas pressure: 4Pa
Methane (CH ₄ ) gas flow rate was adjusted at 5 sccm to 200 sccm.
The flow rate was adjusted with a tetramethylsilane (TMS) gas flow rate (0.1 sccm to 5 sccm).

As a result of analysis by Raman spectroscopy in the same manner as in Example 1-1, diamond-like carbon was formed in the surface layer.
When the contents of Si, O, and C in the surface layer were confirmed by XPS analysis in the same manner as in Example 1-1, the composition ratio was Si: O: C = 0.03: 0: 0.97. Met.
The coefficient of friction of the surface layer was measured in the same manner as in Example 1-1, and it was 0.06.

(Example 2-1)
<Manufacture of optical element 1 using optical element molding die 1>
The glass 1 having the composition shown in Table 1 below is used as the optical element material, the optical element molding die 1 is used as the optical element molding die, the optical element material is heated to 580 ° C. in a nitrogen atmosphere, and the load is 50 kgf. Press molding was performed, and 100 shots of a 4 mm diameter, 1.5 mm thick, convex optical lens were produced.
2 and 3 are schematic explanatory views of press molding. FIG. 2 is an explanatory diagram before press molding, and FIG. 3 is an explanatory diagram at the time of press molding. 2 and 3, reference numeral 11 indicates a base material (upper mold), reference numeral 12 indicates a surface layer, reference numeral 13 indicates an optical element material, and reference numeral 14 indicates a base material (lower mold).

FIG. 4 is a microscopic image of the surface of the optical element molding die 1 after 100 shot molding of Example 2-1. From the results shown in FIG. 4, in the optical element molding die 1, the surface layer is not damaged, such as roughening or peeling, even after 100 shot molding, and the surface layer is excellent in film hardness and reacts with the optical element material. Thus, it was found that the optical element molding die 1 was excellent in releasability and durability.
Further, no can (crack) was generated in the molding of the optical lens.
Therefore, it was found that the optical element molding die 1 was not damaged even when exceeding 100 shots, and an optical element could be manufactured.

(Example 2-2)
<Manufacture of optical element 1 using optical element molding die 2>
An optical element was produced in the same manner as in Example 2-1, except that the optical element molding die 1 was replaced with the optical element molding die 2 in Example 2-1.

FIG. 5 is a microscopic image of the surface of the optical element molding die 2 after 100 shot molding of Example 2-2. From the results of FIG. 5, in the optical element molding die 2, the surface layer is not damaged, such as roughening or peeling, even after 100 shot molding, the surface layer is excellent in film hardness, and reacts with the optical element material. Therefore, it was found that the optical element molding die 2 was excellent in releasability and durability.
Further, no can (crack) was generated in the molding of the optical lens.
Therefore, it was found that the optical element molding die 2 was not damaged even when exceeding 100 shots, and it was possible to produce an optical element.

(Example 2-3)
<Manufacture of optical element 2 using optical element molding die 2>
In Example 2-2, the point where the glass 1 was used was replaced with the glass 2 having the composition shown in Table 2 below, and the point where the heating temperature was 580 ° C was replaced with 570 ° C. The optical element was manufactured in the same manner as in Example 2.

FIG. 6 is a microscopic image of the surface of the optical element molding die 2 after 100 shot molding of Example 2-3. From the results shown in FIG. 6, in the optical element molding die 2, the surface layer is not damaged, such as roughening or peeling, even after 100 shot molding, the surface layer is excellent in film hardness, and reacts with the optical element material. Therefore, it was found that the optical element molding die 2 was excellent in releasability and durability.
Further, no can (crack) was generated in the molding of the optical lens.
Therefore, it was found that the optical element molding die 2 was not damaged even when exceeding 100 shots, and it was possible to produce an optical element.

(Example 2-4)
<Manufacture of optical element 3 using optical element molding die 2>
In Example 2-2, the point where the glass 1 was used was replaced with the glass 3 having the composition shown in Table 3 below, and the point where the heating temperature was 580 ° C was replaced with 560 ° C. The optical element was manufactured in the same manner as in Example 2.

FIG. 7 is a microscopic image of the surface of the optical element molding die 2 after 100 shot molding of Example 2-4. From the results shown in FIG. 7, in the optical element molding die 2, the surface layer is not damaged, such as roughening or peeling, even after 100 shot molding, the surface layer is excellent in film hardness, and reacts with the optical element material. Therefore, it was found that the optical element molding die 2 was excellent in releasability and durability.
Further, no can (crack) was generated in the molding of the optical lens.
Therefore, it was found that the optical element molding die 2 was not damaged even when exceeding 100 shots, and it was possible to produce an optical element.

(Example 2-5)
<Manufacture of optical element 1 using optical element molding die 3>
An optical element was manufactured in the same manner as in Example 2-1, except that the optical element molding die 1 was replaced with the optical element molding die 3 in Example 2-1.

FIG. 8 is a microscopic image of the surface of the optical element molding die 3 after 100 shot molding of Example 2-5. From the results shown in FIG. 8, in the optical element molding die 3, the surface layer is not damaged, such as roughening or peeling, even after 100 shot molding, the surface layer is excellent in film hardness, and reacts with the optical element material. Therefore, it was found that the optical element molding die 3 was excellent in releasability and durability.
Further, no can (crack) was generated in the molding of the optical lens.
Therefore, it was found that the optical element molding die 3 was not damaged even when exceeding 100 shots, and an optical element could be manufactured.

(Example 2-6)
<Manufacture of optical element 1 using optical element molding die 4>
An optical element was manufactured in the same manner as in Example 2-1, except that the optical element molding die 1 was replaced with the optical element molding die 4 in Example 2-1.

FIG. 9 is a microscopic image of the surface of the optical element molding die 4 after 100 shot molding of Example 2-6. From the results shown in FIG. 9, in the optical element molding die 4, the surface layer is not damaged, such as roughening or peeling, even after 100 shot molding, the surface layer is excellent in film hardness, and reacts with the optical element material. Thus, it was found that the optical element molding die 4 was excellent in releasability and durability.
Further, no can (crack) was generated in the molding of the optical lens.
Therefore, it was found that the optical element molding die 4 was not damaged even when exceeding 100 shots, and an optical element could be manufactured.

(Example 2-7)
<Manufacture of optical element 1 using optical element molding die 5>
An optical element was manufactured in the same manner as in Example 2-1, except that the optical element molding die 1 was replaced with the optical element molding die 5 in Example 2-1.

FIG. 10 is a microscopic image of the surface of the optical element molding die 5 after 100 shot molding of Example 2-7. From the results shown in FIG. 10, in the optical element molding die 5, even after 100 shot molding, the surface layer has no damage such as roughening or peeling, the surface layer has excellent film hardness, and reaction with the optical element material. Therefore, it was found that the optical element molding die 5 was excellent in releasability and durability.
Further, no can (crack) was generated in the molding of the optical lens.
Therefore, it was found that the optical element molding die 5 was not damaged even when exceeding 100 shots, and an optical element could be manufactured.

(Example 2-8)
<Manufacture of optical element 1 using optical element molding die 6>
An optical element was manufactured in the same manner as in Example 2-1, except that the optical element molding die 1 was replaced with the optical element molding die 6 in Example 2-1.

FIG. 11 is a microscopic image of the surface of the optical element molding die 6 after 100 shot molding of Example 2-8. From the results of FIG. 11, in the optical element molding die 6, the surface layer is not damaged, such as roughening or peeling, even after 100 shot molding, the surface layer is excellent in film hardness, and reacts with the optical element material. Therefore, it was found that the optical element molding die 6 was excellent in releasability and durability.
Further, no can (crack) was generated in the molding of the optical lens.
Therefore, it was found that the optical element molding die 6 was not damaged even when exceeding 100 shots, and an optical element could be manufactured.

(Comparative Example 2-1)
<Manufacture of optical element-1 using optical element molding die 7>
An optical element was manufactured in the same manner as in Example 2-1, except that the optical element molding die 1 was replaced with the optical element molding die 7 in Example 2-1.

FIG. 12 is a microscopic image of the surface of the optical element molding die 7 after 100 shot molding of Comparative Example 2-1. From the results of FIG. 12, it was found that in the optical element molding die 7 having a surface layer of diamond-like carbon that does not contain Si and O, the surface layer is roughened or peeled off. The surface layer was roughened or peeled off after 60 shot molding.
Further, in the molding of the optical lens, a can (crack) occurred after 30 shots.

(Comparative Example 2-2)
<Manufacture of optical element 2 using optical element molding die 7>
In Comparative Example 2-1, the point of using glass 1 was replaced with glass 2 having the composition shown in Table 2, and the heating temperature was 580 ° C, except that the point was changed to 570 ° C. In the same manner as in Example 1, an optical element was produced.

FIG. 13 is a microscopic image of the surface of the optical element molding die 7 after 100 shot molding of Comparative Example 2-2. From the results of FIG. 13, it was found that in the optical element molding die 7 having a diamond-like carbon surface layer containing no Si and O, the surface layer was roughened or peeled off. The surface layer was roughened or peeled off after 60 shot molding.
Further, in the molding of the optical lens, a can (crack) occurred after 30 shots.

(Comparative Example 2-3)
<Manufacture of optical element using optical element molding die 7-3>
In Comparative Example 2-1, the point of using glass 1 was replaced with glass 3 having the composition shown in Table 3, and the heating temperature was 580 ° C. In the same manner as in Example 1, an optical element was produced.

FIG. 14 is a microscopic image of the surface of the optical element molding die 7 after 100 shot molding of Comparative Example 2-3. From the results of FIG. 14, it was found that in the optical element molding die 7 having a diamond-like carbon surface layer containing no Si and O, the surface layer was roughened or peeled off. The surface layer was roughened or peeled off after 60 shot molding.
Further, in the molding of the optical lens, a can (crack) occurred after 30 shots.

(Comparative Example 2-4)
<Manufacture of Optical Element Using Optical Element Molding Mold-1>
An optical element was manufactured in the same manner as in Comparative Example 2-1, except that the optical element molding die 7 was replaced with the optical element molding die 8 in Comparative Example 2-1.

FIG. 15 is a microscopic image of the surface of the optical element molding die 8 after 100 shot molding in Comparative Example 2-4. From the results of FIG. 15, it was found that in the optical element molding die 8 having a diamond-like carbon surface layer containing no O, the surface layer was roughened or peeled off. The surface layer was roughened or peeled off after one shot molding.
Further, in the molding of the optical lens, a can (crack) occurred after one shot molding.

The examples and comparative examples are summarized in Table 4.
In the column of “peeling (mold)” in Table 4, “◯” indicates “the mold is not damaged at the time of 100 shot molding and can be molded beyond 100 shots”, and “×” indicates “100 The number in the parenthesis indicates the number of shots when the surface layer is rough or peeled off. “100 ↑” indicates that “the surface layer was not roughened or peeled off during 100 shot molding.”
Further, in the “can” column, “◯” indicates that “cracks did not occur during 100 shot molding”, and “x” indicates that “cracks occurred during 100 shot molding”. The numbers in parentheses indicate the number of shots when a crack occurs. “100 ↑” indicates that “no cracks occurred during 100 shot molding”.

  From the results of Table 4, the friction coefficient of the surface layers of the optical element molding dies 1 to 6 in which the surface layer is diamond-like carbon containing Si and O is diamond-like carbon in which the surface layer does not contain Si and O. It was found that the friction coefficient of the surface layer of the optical element molding die 7 is lower than that.

  Further, optical element molding dies 1 to 6 whose surface layer is diamond-like carbon containing Si and O are optical element molding dies 7 whose surface layer is diamond-like carbon not containing Si and O, The surface layer is superior to the optical element molding die 8 in which the optical element is molded and the evaluation of the can as compared with the optical element molding die 8 whose surface layer is diamond-like carbon not containing O. It has been found that it has excellent adhesion to the resin, and is excellent in releasability and durability.

The optical element molding die of the present invention has low reactivity with the optical element material, and can reduce the friction coefficient between the optical element material and the surface layer of the optical element molding die. Since it is excellent in releasability and durability due to excellent adhesion between the surface layer and the surface layer, optical element materials including highly reactive TiO ₂ , Nb ₂ O ₅ , WO ₃ , Bi ₂ O _3, etc. It can be suitably used for molding a lens.

DESCRIPTION OF SYMBOLS 1 Gas 2 High frequency electrode 3 Base material 4 High frequency electrode 5 Matching box 6 High frequency power supply 11 Base material (upper mold)
12 Surface layer 13 Optical element material 14 Base material (lower mold)

Claims (3)

A substrate and a surface layer;
The optical element molding die, wherein the surface layer includes diamond-like carbon containing Si and O.   An optical element manufacturing method, wherein an optical element material is molded using the optical element molding die according to claim 1. An optical element manufactured by the method for manufacturing an optical element according to claim 2.