JP4962964B2 - Glass lens mold and manufacturing method thereof - Google Patents

Description

  The present invention relates to a mold for molding a glass lens and a method for manufacturing the same.

The glass lens is molded at a high temperature of 300 to 700 ° C. using a glass mold. At this time, it is necessary that the so-called rough skin due to oxidation does not occur at a high temperature and that the glass does not fuse to the mold after press molding. Therefore, at present, a method of protecting the glass surface while securing incompatibility with glass by forming a film on the mold surface is employed. As such a film, there are generally a rare metal film centered on platinum, a DLC film, and an amorphous thin film mainly composed of carbon and hydrogen (for example, Patent Document 1).
Japanese Patent Laid-Open No. 3-240957

  However, platinum is difficult to obtain, and other coatings also suffer from the problem that the coating is severely degraded by high-temperature molding, and peeling from the mold is likely to occur. Therefore, the current glass lens mold has room for improvement.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a glass lens mold having excellent adhesion in high temperature molding, and a method for producing the same.

A glass lens mold according to the present invention is made to solve the above problems, and includes a base having a film formation surface, and a film containing Si and C, which is coated on the film formation surface. And the content ratio of Si and C in the film formation surface layer in contact with the film formation surface is different from the content ratio of Si and C in the surface layer exposed on the surface of the film in the layer thickness direction of the film. , Moreover, the content ratio of C in the surface layer, the rather high than the content ratio of C in the film-forming surface layer, C content of the surface layer is a 70-87 atomic%, the film forming surface The C content of the layer is 52 to 70 atomic%.

  In the above glass lens mold, the coating film is composed of the film-forming surface layer, the intermediate layer, and the surface layer arranged from the film-forming surface side, and the film-forming surface layer and the surface layer include Si and It is preferable that the C content ratio is substantially constant, and that the C content increases as the intermediate layer goes to the surface side.

Moreover, the manufacturing method of the shaping | molding die for glass lenses which concerns on this invention is made | formed in order to achieve the said objective, the target containing Si is prepared, and inert gas and hydrocarbon gas are a predetermined ratio. A first step of forming a first layer containing Si and C on a film formation surface on a base by supplying a mixed gas mixed in step 1 and performing sputtering for a predetermined time; and the mixed gas While increasing the ratio of the hydrocarbon gas in the second step of forming the second layer by performing the subsequent sputtering, and performing the sputtering while maintaining the ratio of the hydrocarbon gas in the mixed gas constant. A third step of forming a layer, wherein the C content of the third layer is 70 to 87 atomic% in the first step, and the first step includes the first step. layer C content is a 52 to 70 atomic%.

  In the said manufacturing method, it is preferable that the flow rate ratio of the hydrocarbon gas in a 3rd step is 10 to 17%.

  Moreover, it is preferable that the flow rate ratio of the hydrocarbon gas in the first step is 5 to 10%.

  According to the glass lens mold and the method for producing the same according to the present invention, the adhesion of the coating to the base of the mold can be greatly improved in high temperature molding.

  Hereinafter, an embodiment of a glass lens mold and a method for producing the same according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a glass lens mold according to this embodiment.

  As shown in FIG. 1, the glass lens mold according to the present embodiment includes a base 1 having a film-forming surface 11 of a glass lens to be molded, and the film-forming surface 11 of the base 1. The film 2 is coated on the surface. Hereinafter, the base 1 and the coating 2 will be described in more detail.

(Base)
As the material constituting the base 1, various carbide materials such as tungsten carbide (WC), tungsten carbide (WC) -cobalt (Co), iron or iron alloy, silicon carbide, silicon nitride ceramic materials, Carbon can be used.

  The film formation surface 11 is formed on the surface of the base, and is formed along the shape of the glass lens to be molded. For example, it can be a convex curved surface, a concave curved surface, or a flat surface. The film-forming surface 11 is generally mirror-finished by diamond wrapping or the like, but the surface roughness (Ra) may be about 0.001 μm to 0.01 μm.

(Coating)
The coating 2 is formed of a material mainly containing Si and C. And the content rate of Si and C differs in the layer thickness direction of the film 2. That is, the above-described content rate differs between the film-forming surface layer in contact with the film-forming surface 11 and the surface layer exposed on the surface of the coating 2 opposite to the film-forming surface 11, and the C content rate is large in the surface side region. It has become. Therefore, in the present embodiment, at least two layers having different Si and C contents are formed. As components other than Si and C, for example, boron, nitrogen, hydrogen, and various metals can be added.

  For example, as shown in FIG. 2, the coating 2 is composed of two layers, that is, a film-forming surface layer 21 on the film-forming surface side and a surface layer 22 on the surface-side. In these layers 21 and 22, the content ratios of Si and C may be substantially constant, or the content ratios may change in the thickness direction inside the layers. However, in any case, the C content of the surface layer 22 is set to be larger than the content of the film-forming surface layer 21.

  Alternatively, as shown in FIG. 3, the coating 2 can be composed of three layers, a film formation surface layer 21, an intermediate layer 23, and a surface layer 22, which are arranged from the film formation surface 11 side. And about the film-forming surface layer 21 and the surface layer 22, the content rate of Si and C in the inside is made substantially constant, and the content rate of C of the surface layer 22 is larger than the content rate of the film-forming surface layer 21. To do. For the intermediate layer 23, the C content is gradually increased from the film-forming surface layer 21 to the surface layer 22. That is, in the intermediate layer 23, the content of C is substantially the same as that of the film-forming surface layer 21 in the region in contact with the film-forming surface layer 21, and the content of the surface layer 22 is approximately the same in the region of contact with the surface layer 22.

Here, in any case of FIG. 2 and FIG. 3, in the film formation surface layer 21, the C content is preferably 52 to 70 atomic%. On the other hand, in the surface layer 22, it is preferable that the C content is 70 to 87 atomic%. Moreover, it is preferable that the layer thickness of the film 2 is 0.1-2 micrometers as a whole.
(Method for producing coating)
As a manufacturing method of the mold, various methods such as an ion plating method and a CVD method can be cited, and for example, sputtering can be employed. In this case, a material containing Si is used as the target.

  As the film formation atmosphere gas, a hydrocarbon gas such as methane, ethane, ethylene, or acetylene, or a carbon-containing gas such as carbon monoxide, halogen, or carbon can be used. Furthermore, a mixed gas obtained by appropriately adding an inert gas such as helium, argon, or neon to these gases can be used as a film formation atmosphere gas. As other types of sputtering, magnetron sputtering in which a magnet is disposed in the vicinity of the target, counter sputtering in which the target is disposed facing each other, and the like can be used.

  In the case of forming the above-described three-layer coating, for example, the film is formed in three stages as shown in FIG. First, a mixed gas of hydrocarbon gas and inert gas is supplied at a predetermined flow rate, and sputtering is performed for a predetermined time. Thereby, the film-forming surface layer 21 described above is formed. Then, after a predetermined time has elapsed, sputtering is continued while gradually increasing the flow rate ratio of the hydrocarbon gas. At this stage, the intermediate layer 23 described above is formed. At this time, the flow rate of the entire mixed gas is kept constant, and the flow rate ratio of each gas is changed. Then, after increasing the flow rate of the hydrocarbon gas to a predetermined ratio, the sputtering is continued for a predetermined time with the flow rate kept constant. Thereby, the surface layer 22 mentioned above is formed.

  Next, examples of the present invention will be described. However, the present invention is not limited to the following examples. Here, a film was formed on the film formation surface of the base by sputtering as follows.

A. Base The base was a super hard material, and the film formation surface was a circle having a diameter of 20.5 mm and a thickness of about 5 to 10 mm. And the film-forming surface was mirror-finished by diamond drapping.

B. Film formation method Film formation by sputtering is performed as follows.
(1) Target A metal Si target having a purity of 99.99 percent was used. The shape is a cylindrical shape with a diameter of 152.4 mm and a thickness of 6 mm.
(2) Film forming gas atmosphere Sputtering is performed while changing the flow rate ratio of the mixed gas of argon gas and methane gas in three stages. That is, the mixed gas is supplied at a constant flow rate for 3,600 seconds in the first stage. Subsequently, after the mixing ratio of methane gas is increased in 600 seconds in the second stage, the mixed gas is supplied at a constant ratio for 600 seconds in the third stage. Note that the total flow rate of the mixed gas was constant over the entire process, and the flow rate was 399 sccm. For the evaluation test, first, film formation was carried out by changing the flow rate of the mixed gas in the first stage and changing the flow rate of the mixed gas in the third stage. Further, film formation was performed by changing the flow rate ratio of the mixed gas in the third stage and changing the flow ratio of the mixed gas in the first stage.

-First stage constant In the first stage, argon gas 361 sccm and methane gas 38 sccm were used, and the flow rate in the third stage was changed as follows. Further, the C content in the deposited layer was also measured. The content of C was measured by EDX, and the content of C was calculated based on the calculation formula of C / (Si + C) from At% of Si and C obtained by EDX.

-Third stage constant In the third stage, the argon gas was 353 sccm and the methane gas was 46 sccm, and the flow rate in the first stage was changed as follows. Further, the C content in the deposited layer was also measured.

In Test Nos. 7 and 9, the C content is constant throughout the coating.
(3) Film formation conditions The output was 1.5 kW.

C. Evaluation test
(1) Adhesion Scratch Test After the above film formation, the film was heated at 600 ° C. for 1,998 seconds, and then the adhesion of the film to the film formation surface was evaluated by a scratch test. The indenter used was a conical diamond indenter with a tip apex angle of 120 ° and a radius of curvature of 0.2 mm. Using this indenter, a scratch test was performed on the coating under the conditions of a load application speed of 100 N / min and an indenter scanning speed of 10 mm / min. The results are as follows.

As a result of the above test, in Test Nos. 2 to 8 in which the C content of the molded film layer was fixed, a sufficient result was obtained as a peeling load. On the other hand, in Test Nos. 9 to 15 in which the C content of the surface layer was fixed, a good peeling load could be obtained except for Test Nos. 9 and 15.

(2) Releasability test In the above test Nos. 3, 7, and 8, a releasability test using a glass mold press was performed under the following conditions. In this test, the glass material BK-7 was placed on a film forming die and pressed at 670 ° C. for 999 seconds to visually evaluate peeling of the coating film.

  As a result, as shown in FIGS. 5 to 7, the film was not peeled off in Test No. 3, but in Test Nos. 6 and 7, the film adhered to the glass and peeled off. .

  From the above results, it was found that the molding film layer and the surface layer had a different content ratio than the C content ratio, and the surface layer had a higher content ratio to obtain a better peeling load. . In particular, the C content of the molded film layer is preferably 52 to 70 atomic%, and the C content of the surface layer is considered to be preferably 70 to 87 atomic%.

It is sectional drawing of the shaping | molding die for glass lenses which concerns on one Embodiment of this invention. It is sectional drawing which shows an example of the film shown in FIG. It is sectional drawing which shows the other example of the film shown in FIG. It is a graph which shows the time change of the ratio of the flow volume of the hydrocarbon gas in a film-forming process. It is a photograph which shows the result of a mold release test. It is a photograph which shows the result of a mold release test. It is a photograph which shows the result of a mold release test.

Explanation of symbols

1 Base 11 Deposition surface 2 Coating

Claims (5)

A base having a film-forming surface;
A film coated with the film-forming surface and containing Si and C;
The content ratio of Si and C in the film-forming surface layer in contact with the film-forming surface in the layer thickness direction of the film is different from the content ratio of Si and C in the surface layer exposed on the surface of the film, and , the content ratio of C in the surface layer, rather higher than the content ratio of C in the film-forming surface layer,
The C content of the surface layer is 70 to 87 atomic%;
The glass lens mold having a C content of the film-forming surface layer of 52 to 70 atomic% . The coating film is composed of a layer of the film formation surface layer, an intermediate layer, and the surface layer disposed from the film formation surface side,
The film-forming surface layer and the surface layer have a substantially constant content ratio of Si and C,
The mold for glass lens according to claim 1, wherein the intermediate layer has an increasing C content as it goes to the surface side. A target containing Si is prepared, a mixed gas in which an inert gas and a hydrocarbon gas are mixed at a predetermined ratio is supplied, and sputtering is performed for a predetermined time. A first step of forming a first layer containing C;
A second step of forming a second layer by subsequently performing sputtering while increasing the proportion of the hydrocarbon gas in the mixed gas;
A third step of forming a third layer by performing sputtering while keeping the ratio of the hydrocarbon gas in the mixed gas constant,
In the first step, the C content of the third layer is 70 to 87 atomic%,
In the third step, the method for producing a glass lens mold , wherein the C content of the first layer is 52 to 70 atomic% . The manufacturing method of the shaping | molding die for glass lenses of Claim 3 whose flow-rate ratio of the hydrocarbon gas in a said 3rd step is 10 to 17%. The manufacturing method of the shaping | molding die for glass lenses of Claim 3 or 4 whose flow rate ratio of the hydrocarbon gas in a said 1st step is 5 to 10%.