JP2008143730A - Die for molding optical element, and method for producing die for molding optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a die for molding an optical element by which the micropeeling from a molding face and the seizure of an optical element can be suppressed. <P>SOLUTION: The method for producing a die for molding an optical element comprises: an intermediate layer forming stage where, on the upper face 2a of a base material 2 comprising a tungsten carbide alloy, an intermediate layer forming layer 3 composed of a mixture comprising at least one kind of element selected from platinum, palladium, iridium, osmium, ruthenium, rhenium, hafnium and tantalum, and one or more kinds of elements comprised in the base material 2 is formed; a working layer forming stage where, on the upper face 3a of the intermediate layer 3, a working layer 5 composed of simple substance including at least one kind of element selected from platinum, palladium, iridium, osmium, ruthenium, rhenium, hafnium and tantalum or a mixture thereof is formed; a sintering stage where the intermediate layer 3 and the working layer 5 are integrally sintered; and a working stage where the working layer 5 is worked, so as to be a shape close to that of a desired optical element. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  Various manufacturing methods have been proposed to improve the durability of the molding surface when manufacturing an optical element molding die. For example, the upper surface of a sintered body having excellent mechanical strength and excellent heat resistance, such as a cemented carbide whose main component is tungsten carbide (hereinafter referred to as WC), is approximated to a desired optical element. Process into shape. Thereafter, there is a method of forming a protective layer having a metal material such as platinum or iridium by PVD (physical vapor deposition) such as RF sputtering, ion beam sputtering, or vapor deposition, or CVD (chemical vapor deposition). It has been proposed (see, for example, Patent Document 1).

Further, a cutting layer made of an amorphous metal or alloy such as nickel-phosphorus is formed on the surface of the base material described above. Thereafter, a method has been proposed in which the cutting layer is cut to obtain a molding surface (for example, see Patent Document 2).
JP 2003-95669 A JP 2003-246629 A

  However, in the method described in Patent Document 1, since the protective layer is formed as a thin film, the protective layer peels off due to splash at the time of film formation, minute foreign matter, and deposits that cannot be removed by cleaning. In addition, oxidation degradation is accelerated by the heat cycle accompanying the molding, and the micro-peeling of the protective layer and the burn-in of the optical element occur and become defective. Furthermore, when the protective layer is peeled off, the surface of the base material is exposed to the outside, and the base material becomes unusable due to oxidative degradation.

  Further, in the method described in Patent Document 2, since the cutting layer is formed of an amorphous metal or alloy such as nickel-phosphorus, the releasability is low, and optical molding is performed at a high temperature such as glass. The element burns out. Moreover, since the base material and the cutting layer are sintered with dissimilar materials, the strength of the joint between the base material and the cutting layer is low, and is easily cracked.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a mold for molding an optical element that can suppress minute peeling from the molding surface and seizure of the optical element.

The present invention employs the following means in order to solve the above problems.
The method for producing an optical element molding die according to the present invention includes at least one element selected from platinum, palladium, iridium, osmium, ruthenium, rhenium, hafnium, and tantalum on the upper surface of a substrate having a tungsten carbide alloy, An intermediate layer forming step of forming an intermediate layer made of a mixture having one or more elements of the base material, and platinum, palladium, iridium, osmium, ruthenium, rhenium, hafnium, tantalum on the upper surface of the intermediate layer Desired for the processed layer, a processed layer forming step for forming a processed layer composed of a single element or a mixture of at least one element selected, a sintering step for integrally sintering the intermediate layer and the processed layer, and the processed layer And a processing step of processing into a shape approximate to that of the optical element.

  The method for manufacturing an optical element molding die according to the present invention is a method for manufacturing the optical element molding die, wherein the element ratio of the intermediate layer is increased stepwise in the thickness direction of the intermediate layer. It is characterized by changing.

  The method for manufacturing an optical element molding die according to the present invention is a method for manufacturing the optical element molding die, wherein a discharge plasma sintering method is used in the sintering step.

  The optical element molding die according to the present invention is manufactured by the method for manufacturing an optical element molding die according to the present invention.

  According to the present invention, it is possible to suppress minute peeling of the molding surface, burn-in of the optical element, and oxidative deterioration of the base material due to it.

An embodiment according to the present invention will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1, the optical element molding die 1 according to the present embodiment includes at least one of a base material 2 having a WC alloy and platinum, palladium, iridium, osmium, ruthenium, rhenium, hafnium, and tantalum. And an intermediate layer 3 composed of a mixture of one or more elements of the substrate and at least one element selected from platinum, palladium, iridium, osmium, ruthenium, rhenium, hafnium, and tantalum. A processed layer 5 made of a single substance or a mixture and formed on the upper surface 3 a of the intermediate layer 3 is provided.

A method for manufacturing the optical element molding die 1 will be described.
This manufacturing method includes an intermediate layer forming step for forming the intermediate layer 3 on the upper surface 2a of the substrate 2, a processed layer forming step for forming the processed layer 5 on the upper surface 3a of the intermediate layer 3, and the intermediate layer 3 and the processing. A sintering process for integrally sintering the layer 5; and a processing process for processing the processed layer 5 into a shape approximating a desired optical element.

In the present embodiment, a sintering process using a discharge plasma sintering method is performed with the configuration shown in FIG.
First, the WC alloy processed into the base material shape of the desired optical element molding die 1 is placed on the lower side in the sintering jig 11 extending in the vertical direction.

  And on the upper surface 2a of the base material 2, the mixed powder which has at least 1 type of elements among platinum, palladium, iridium, osmium, ruthenium, rhenium, hafnium, and tantalum, and 1 or more types of elements which the base material 2 has. Arranged as the intermediate layer 3 (intermediate layer forming step), further, a powder of at least one element selected from platinum, palladium, iridium, osmium, ruthenium, rhenium, hafnium, tantalum, or a mixture powder, It arrange | positions as the process layer 5 (process layer formation process).

  Then, after adjusting the filling amount so that each of the intermediate layer 3 and the processed layer 5 has a desired thickness, pulse discharge is performed while applying pressure to the upper punch 12 and the lower punch 13, and the discharge plasma sintering method is performed. It is used and sintered together (sintering process).

After the sintering process, the process shifts to a processing process, where the processed layer 5 formed using grinding is processed into a desired optical element approximate shape, and the molding surface 1a is finished using polishing. Note that finishing may be performed by cluster ion beam or ion milling instead of polishing.
In this way, the processing dirt is removed and dried to obtain the desired optical element molding die 1.

  According to this method for manufacturing the optical element molding die 1, it is possible to manufacture the optical element molding die 1 having no splash or minute foreign matter on the molding surface 1a. Therefore, even if the optical element is molded using this, peeling of the molding surface 1a, burn-in of the optical element, and oxidative deterioration of the base material 2 due to this can be suppressed, and heat resistance can be improved.

  Moreover, a predetermined thickness can be given to the processed layer, and even when irregularities such as scratches occur on the molding surface 1a, the processed layer can be reprocessed and reused.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
If the material which comprises the intermediate | middle layer 3 and the process layer 5 is a combination of the material mentioned above, all can have the same effect.

Example 1
As an intermediate layer, a mixed powder of platinum and WC with a ratio of 50% by weight is arranged on the upper surface of the base material, and further, a mixed powder of platinum and iridium with a ratio of 50% by weight is formed thereon as a processed layer. Arranged. Then, after adjusting the filling amount so that the thickness of the intermediate layer was 0.5 mm and the thickness of the processed layer was 3 mm, sintering was performed by a discharge plasma sintering method.

  In the processing step, a desired optical element approximate shape was processed using grinding, the molded surface was finished using polishing, processing dirt was removed by ultrasonic cleaning, and then vacuum drying was performed.

  When the appearance of the manufactured optical element molding die was observed with a microscope, a good molding surface free from the splash and minute foreign matter found in the conventional one was secured. Then, a molding test was performed in which the optical element molding die was heated to 650 ° C. or higher. As a result, oxidation of the base material was confirmed in the past, and minute peeling and optical element burn-in were confirmed at about 500 shots. However, in this example, a molding surface having no such thing was secured even at 1000 shots.

Even if the same molding test was performed at 750 ° C. or higher and 850 ° C. or higher, the results were the same.
Moreover, when it heated at 650 degreeC or more and performed 5000 shot, although the oxidation of the molding surface was able to be confirmed, there was no damage to a base material. Thereafter, the molding surface was reworked and a molding test was performed again. As a result, even with 1000 shots, it was possible to secure a molding surface that was free from minute peeling and optical element burn-in.

(Example 2)
Compared with Example 1, the element ratio (weight ratio) of platinum and iridium was set to three intermediate layers different in three stages in the thickness direction.
As an intermediate layer, a mixed powder of 25% by weight of platinum and 75% by weight of WC is disposed on the upper surface of the substrate, and a mixed powder of 50% by weight of platinum and 50% by weight of WC is disposed thereon, and further, 75% by weight of platinum is disposed thereon. %, WC 25 wt% mixed powder was placed. Further, a mixed powder of platinum and iridium having a ratio of 50% by weight was disposed on the intermediate layer as a processed layer. Then, the filling amount was adjusted so that each of the intermediate layers had a thickness of 0.5 mm and the processed layer had a thickness of 3 mm, and then sintered by the discharge plasma sintering method.

  When the appearance of the manufactured optical element molding die was observed with a microscope, the same good molding surface as in Example 1 was secured. When a molding test of the optical element molding die was performed at the same temperature and shot as in Example 1, the same result as in Example 1 was obtained.

  Moreover, when the strength comparison test of the optical element molding die of this example and Example 1 was performed, in the optical element molding die of this example, the base material and the intermediate layer, and the intermediate layer and the processed layer As a result, the strength was improved from that of Example 1.

(Example 3)
As an intermediate layer, a platinum-iridium alloy and WC were mixed as a mixed powder at a ratio of 50% by weight and placed on the upper surface of the substrate. Further, a mixed powder of platinum and iridium having a ratio of 50% by weight was disposed thereon as a processed layer. Then, after adjusting the filling amount so that the thickness of the intermediate layer was 0.5 mm and the thickness of the processed layer was 3 mm, sintering was performed by a discharge plasma sintering method.

  In the processing step, a desired optical element approximate shape was processed using grinding, the molded surface was finished with a cluster ion beam, processing stains were removed by ultrasonic cleaning, and then vacuum drying was performed.

Example 4
As an intermediate layer, a mixed powder of platinum and iridium and a WC powder were mixed as a mixed powder at a ratio of 50% by weight and placed on the upper surface of the substrate. Further, a mixed powder of iridium and rhenium in a ratio of 50% by weight was disposed thereon as a processed layer. Then, after adjusting the filling amount so that the thickness of the intermediate layer was 0.5 mm and the thickness of the processed layer was 3 mm, sintering was performed by a discharge plasma sintering method.

  In the processing step, grinding was performed to obtain a desired optical element approximate shape, the molding surface was finished by ion milling, processing dirt was removed by ultrasonic cleaning, and then vacuum drying was performed.

  When the appearance of the manufactured optical element molding die was observed with a microscope, the same good molding surface as in Example 1 was secured. When a molding test of the optical element molding die was performed at the same temperature and shot as in Example 1, the same result as in Example 1 was obtained.

It is sectional drawing which shows the optical element shaping die based on one Embodiment of this invention. It is explanatory drawing which shows the method of manufacturing the optical element shaping die concerning one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical element shaping | molding die 2 Base material 2a Upper surface 3 Intermediate | middle layer 3a Upper surface 5 Processed layer

Claims (4)

From a mixture having at least one element of platinum, palladium, iridium, osmium, ruthenium, rhenium, hafnium, tantalum and one or more elements of the substrate on the upper surface of the substrate having a tungsten carbide alloy. An intermediate layer forming step of forming an intermediate layer,
On the upper surface of the intermediate layer, a processing layer forming step of forming a processing layer made of a simple substance or a mixture of at least one element selected from platinum, palladium, iridium, osmium, ruthenium, rhenium, hafnium, and tantalum, and
A sintering step of integrally sintering the intermediate layer and the processed layer;
A processing step of processing the processed layer into a shape approximate to a desired optical element;
A method for producing a mold for molding an optical element, comprising:   2. The method for manufacturing an optical element molding die according to claim 1, wherein the element ratio of the intermediate layer is changed stepwise in the thickness direction of the intermediate layer.   3. The method for manufacturing an optical element molding die according to claim 1, wherein a discharge plasma sintering method is used in the sintering step.   An optical element molding die produced by the method for producing an optical element molding die according to any one of claims 1 to 3.

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