JP2008214114A - Mold for molding optical element and optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for molding an optical element, with which an optical element having satisfactory optical characteristics can be produced when a Bi-containing optical element is molded; and to provide the optical element having satisfactory optical characteristics, produced by using the mold. <P>SOLUTION: In the mold 1 for molding the optical element, a molding surface layer 4 containing at least one of Bi and Bi oxide as a main component is provided on the surface on the molding part 2a side of a mold base material 2, and a gradient film layer 3, wherein the constitutive material is gradually changed from the simple body of a metal to the oxide of the metal toward the molding surface layer 4 side from the mold base material 2 side, is provided between the mold base material 2 and the molding surface layer 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical element molding die suitable for molding a Bi (bismuth) -containing optical element, and an optical element molded using the optical element molding die.

A mold used for heating and press-molding an optical element such as an optical lens is required to have excellent properties such as hardness, heat resistance, releasability, and mirror surface workability. As a conventional mold for molding an optical element, there is proposed a mold in which a noble metal coating is applied on the surface of a conductive mold base material made of cemented carbide or silicon carbide (see, for example, Patent Document 1). . In addition, as a conventional mold for optical element molding, a mold base material made of tungsten carbide, cermet, zirconia, SiC, Si ₃ N ₄ or the like is coated with a coating containing carbon as a main constituent element. It has been proposed (see, for example, Patent Document 2).
JP 2001-322827 A Japanese Patent No. 2505893

  However, in the conventional optical element molding die described above, when Bi-containing glass having high refractive index characteristics is molded, Bi contained in the glass material to be molded moves to the mold surface and accumulates on the molding surface. . Then, Bi deposited on the molding surface diffuses into the mold and causes chemical erosion. As a result, the protective coating on the molding surface of the mold deteriorates and the shape of the molding surface collapses. Moreover, the transmittance of the optical element to be molded is reduced by transferring the shape of the molded surface to the molded product or by depositing the deposit (Bi) deposited on the molded surface on the molded product. As described above, in the conventional optical element molding die described above, there is a problem that when the Bi-containing optical element is molded, one that satisfies the optical characteristics cannot be produced.

  The present invention takes into account the above-described conventional problems, and provides an optical element molding die capable of producing an optical element that satisfies optical characteristics when molding a Bi-containing optical element. And it aims at providing the optical element produced with this optical element shaping die and satisfying an optical characteristic.

  An optical element molding die according to the present invention is an optical element molding die used for molding an optical element, wherein at least one of Bi and Bi oxide is formed on the surface of the molding base side of the mold base material. The molding surface layer having one of the main components is provided on an almost entire surface of the surface or having an island-like structure in which the ratio of the total projected area to the area of the surface is 20% or more, Between the mold base material and the molding surface layer, there is provided an inclined film layer that gradually changes from a single metal to an oxide of the metal from the mold base material side to the molding surface layer side. It is characterized by having.

With such a feature, the inclined film layer provided between the mold base material and the molding surface layer has sufficient adhesion strength to the mold base material, so No intermediate layer is required between the membrane layers. Further, since the gradient film layer is a layer changed from a single metal to a covalent bond oxide of the metal, the surface of the gradient film layer on the molding surface layer side is in a thermodynamically most stable state. In addition, since the molding surface layer mainly composed of Bi or Bi oxide is provided on the surface, the surface of the molding surface layer (molding surface) is saturated or close to Bi or Bi oxide. become. As a result, when molding a Bi-containing optical element, the transition of Bi or Bi oxide between the optical element and the molding surface is in an equilibrium state or a state close thereto, and the Bi-containing optical element is transferred to the mold surface. Segregated Bi and Bi oxide are inhibited.
Here, the molding surface layer may be provided on substantially the entire surface of the inclined film layer on the molding surface layer side, but the island-like shape in which the ratio of the total projected area to the surface area is 20% or more. It may be provided with a structure. Moreover, the thing which hits each island of an island-like structure includes a thing with the same thickness and projection diameter of a shaping | molding surface layer other than the thing whose projection diameter is large enough with respect to the thickness of a shaping | molding surface layer.
Note that Bi described above is bismuth, and Bi oxide is bismuth oxide.

  In the optical element molding die according to the present invention, it is preferable that boron (hereinafter referred to as B) is contained in the molding surface layer.

  Thus, by including B in the molding surface layer, the slidability between the optical element of the molded product and the molding surface of the mold is improved.

  In the optical element molding die according to the present invention, the metal is preferably any one of Cr, Ta, Ir, Al, and Si.

The metal materials (Cr, Ta, Ir, Al, Si) described above have good adhesion to the mold base material, and these oxides are thermodynamically stable due to covalent bonds. Further, the above-described metal materials (Cr, Ta, Ir, Al, Si) can be formed in a single film formation step when forming a gradient film layer that changes from a simple substance to an oxide.
Note that Cr is chromium, Ta is tantalum, Ir is iridium, Al is aluminum, and Si is silicon.

  The optical element according to the present invention is characterized by being molded using the optical element molding die described above.

  Due to these characteristics, when an optical element is molded using an optical element molding die, the shape collapsed by chemical erosion is not transferred to the optical element, and the optical element is transferred. There is no deposit on the surface.

  According to the optical element molding die according to the present invention, Bi or Bi oxide, which is a component of the Bi-containing optical element, is provided in advance on the molding surface of the mold and is in an equilibrium state. Since the migration and segregation of Bi and Bi oxide from the optical element during molding are hindered, the optical element molding die is not subject to chemical erosion, and the molding surface is deformed or Bi or Bi Oxide deposition can be prevented. Therefore, it is possible to prevent deposits from adhering to the molded product (Bi-containing optical element) or the shape of the molded surface that has been destroyed by chemical erosion to be transferred to the molded product, and Bi that satisfies the optical characteristics can be prevented. A contained optical element can be produced.

  Hereinafter, first to fourth embodiments of an optical element molding die and an optical element according to the present invention will be described with reference to the drawings.

[First Embodiment]
First, the optical element molding die 1 according to the first embodiment of the present invention will be described. FIG. 1 is a cross-sectional view of an optical element molding die 1.

  As shown in FIG. 1, an optical element molding die 1 includes a mold base material 2 made of, for example, a cemented carbide, and an inclined film layer 3 provided on a surface 2b of a molding portion 2a of the mold base material 2. And a molding surface layer 4 provided on the surface of the gradient film layer 3. The surface of the molding surface layer 4 is the molding surface 5.

  The mold base material 2 is a member processed according to the shape of a desired molded product, and the surface 2b on the molding surface 5 side is formed into a desired molded product shape by, for example, grinding using a diamond grindstone. Processed together. Further, the surface 2b of the mold base material 2 is subjected to a mirror polishing process, and for example, the surface roughness Ry is finished to about 0.05 μm.

The graded film layer 3 is formed from Ta, which is a simple metal, in the thickness D direction from the mold base material 2 side to the molding surface layer 4 side, from its oxide, Ta oxide Ta ₂ O ₅ (metal oxide). It is a graded film that changes gradually. The inclined film layer 3 can be formed on the surface 2b of the mold base 2 by a known thin film forming method. For example, Ta is attached to the surface 2b of the mold base material 2 for which the mirror polishing process has been completed by sputtering. At this time, by gradually increasing the oxygen concentration in the atmosphere, an inclined film that changes from Ta to Ta oxide can be formed.

Since the gradient film layer 3 described above has sufficient adhesion strength to the mold base material 2 (the surface 2b), an intermediate layer is required between the mold base material 2 and the gradient film layer 3. And not. Further, since the surface of the inclined film layer 3 on the molding surface layer 4 side is a covalently bonded Ta oxide (Ta ₂ O ₅ ), it is in a thermodynamically most stable state.

The molding surface layer 4 is a thin film made of Bi oxide (Bi ₂ O ₃ ). The molding surface layer 4 is formed as the outermost layer of the optical element molding die 1, and the surface thereof becomes the molding surface 5 of the optical element molding die 1. The molding surface layer 4 can be formed on the surface of the gradient film layer 3 by a known method. For example, after the gradient film layer 3 is formed on the surface 2b of the mold base material 2, a glass material containing 10 mol% or more of Bi is set in a non-contact state with respect to the gradient film layer 3, and the above-described Bi is contained. The glass material to be molded and the mold base material 2 provided with the inclined film layer 3 are placed in a furnace (not shown) and annealed in an air atmosphere. Thereby, Bi oxide (Bi ₂ O ₃ ) is formed on the surface of the gradient film layer 3. Analysis by a photoelectron spectrometer (XPS: X-ray photoelectron spectroscopy) after the annealing treatment confirms that Bi oxide is formed on the surface of the gradient film layer 3.

As described above, when the molding surface layer 4 made of Bi oxide (Bi ₂ O ₃ ) is formed in advance as the outermost layer of the optical element molding die 1, Bi is saturated in the molding surface 5 as the surface. It becomes a state or a state close to it. Thus, when a Bi-containing optical element containing Bi or Bi oxide (Bi ₂ O ₃ ) is molded, the Bi or Bi oxide (Bi ₂ O ₃ ) between the optical element and the molding surface 5 is formed. The transition becomes an equilibrium state or a state close thereto, and Bi and Bi oxide (Bi ₂ O ₃ ) that migrates from the Bi-containing optical element to the optical element molding die 1 and segregates are inhibited.

For this reason, the optical element molding die 1 is not subjected to chemical erosion, and the shape of the molding surface 5 is prevented from being deformed and Bi or Bi oxide (Bi ₂ O ₃ ) is not deposited on the molding surface 5. Can do. As a result, deposits can be prevented from adhering to the molded product (Bi-containing optical element) or the shape of the molded surface that has been destroyed by chemical erosion can be prevented from being transferred to the molded product, which satisfies the optical characteristics. Bi-containing optical elements can be produced.

  More specifically, a Bi-containing glass material is heated to 560 ° C. in a nitrogen atmosphere with an oxygen concentration of 100 ppm or less using a conventional optical element molding die not provided with the inclined film layer 3 or the molding surface layer 4 described above. When press molding was performed, spiders on the surface of the molded product and seizure on the molding surface of the molded product occurred from 10 shots onward, and it was not possible to obtain a good product on the appearance standard. On the other hand, when the Bi-containing glass material to be molded is heated and pressed under the same conditions using the optical element molding die 1 of the present embodiment having the above-described configuration, a good product can be obtained even at 1000 shots or more. It was possible to confirm that it had sufficient mold durability.

Further, according to the optical element molding die 1 of the present embodiment having the above-described configuration, the surface on the molding surface layer 4 side of the inclined film layer 3 is in a thermodynamically most stable state, so that the molding surface It is possible to prevent the Bi oxide (Bi ₂ O ₃ ) in the layer 4 from entering and diffusing into the gradient film layer 3. Thereby, the optical element molding die 1 is not subjected to chemical erosion, and a Bi-containing optical element that satisfies desired optical characteristics can be produced.

[Second Embodiment]
Next, an optical element molding die 101 according to the second embodiment of the present invention will be described. The configuration of the optical element molding die 101 in the second embodiment will be described with reference to FIG. 1 which is also used in the description of the first embodiment.

The inclined film layer 103 of the optical element molding die 101 is formed from Ir, which is a single metal in the thickness D direction, from the die base material 2 side to the molding surface layer 104 side, and its oxide Ir oxide IrO ₂ ( It is a graded film that gradually changes to (metal oxide). The gradient film layer 103 can be formed on the surface 2b of the mold base 2 by a known thin film formation method, and is the same as the film formation method of the gradient film layer 3 in the first embodiment described above. The film can be formed by this method.

Since the gradient film layer 103 described above has sufficient adhesion strength to the mold base material 2 (surface 2b), an intermediate layer is required between the mold base material 2 and the gradient film layer 103. And not. Further, since the surface of the inclined film layer 103 on the molding surface layer 104 side is a covalently bonded Ir oxide (IrO ₂ ), it is thermodynamically most stable.

The molding surface layer 104 of the optical element molding die 101 is a thin film made of Bi and Bi oxide (Bi ₂ O ₃ ). The molding surface layer 104 can be formed on the surface of the gradient film layer 103 by a known method. For example, after the gradient film layer 103 is formed on the surface 2b of the mold base material 2, a glass material containing 10 mol% or more of Bi is set in a non-contact state with respect to the gradient film layer 103 without applying a load. Put in the molding machine and heat cycle. As a result, Bi and Bi oxide (Bi ₂ O ₃ ) are formed on the surface of the gradient film layer 103. By analyzing the optical element molding die 101 by XPS after the annealing treatment, it can be confirmed that Bi and Bi oxide are present in the outermost layer portion.

  Further, Bi distribution on the surface of the gradient film layer 103 can be confirmed by performing Auger analysis after the annealing treatment. FIG. 2 is a graph showing typical Auger analysis peaks. As shown in FIG. 2, as a result of Auger analysis, Bi and O (oxygen) migrated from the Bi-containing glass material were detected, but Ir was not detected, and the graded film layer made of Ir oxide formed by sputtering. It can be confirmed that a thin layer made of Bi and Bi oxide is uniformly formed on the entire surface of 103 without unevenness.

As described above, when the molding surface layer 104 made of Bi and Bi oxide (Bi ₂ O ₃ ) is formed in advance as the outermost layer of the optical element molding die 101, the molding surface 5 becomes Bi and Bi oxidized. The object (Bi ₂ O ₃ ) becomes saturated or close to it. As a result, similarly to the first embodiment described above, Bi and Bi oxide (Bi ₂ O ₃ ) that migrate from the Bi-containing optical element to the optical element molding die 101 and segregate are inhibited.

  According to the optical element molding die 101 of the present embodiment having the above-described configuration, deposits are attached to the molded product (Bi-containing optical element) or chemically, as in the first embodiment. It is possible to prevent the shape of the molding surface collapsed due to erosion from being transferred to the molded product, and it is possible to produce a Bi-containing optical element that satisfies the optical characteristics.

  More specifically, the Bi-containing glass material is used in a nitrogen atmosphere with an oxygen concentration of 100 ppm or less using the optical element molding die 101 of the present embodiment having the above-described configuration provided with the inclined film layer 103 and the molding surface layer 104. When press molding was performed by heating to 560 ° C. below, a good product could be obtained even at 1500 shots or more, and it was confirmed that it had sufficient mold durability.

Further, according to the optical element molding die 101 of the present embodiment having the above-described configuration, the surface on the molding surface layer 104 side of the inclined film layer 103 is in a thermodynamically most stable state, so that the molding surface Bi and Bi oxide (Bi ₂ O ₃ ) in the layer 104 can be prevented from entering and diffusing into the gradient film layer 103. Thereby, the optical element molding die 101 is not subjected to chemical erosion, and a Bi-containing optical element satisfying desired optical characteristics can be produced.

[Third Embodiment]
Next, an optical element molding die 201 according to the third embodiment of the present invention will be described. The configuration of the optical element molding die 201 according to the third embodiment is the same as that of the optical element molding die 1 according to the first embodiment, and the optical element molding die according to the first embodiment. Compared to the mold 1, the forming method of the molding surface layer 204 is different. Specifically, in the first embodiment described above, the Bi-containing glass material set in a non-contact state and the mold base material 2 are annealed in the air atmosphere, so that the surface of the gradient film layer 3 is formed. Although the molding surface layer 4 made of Bi oxide (Bi ₂ O ₃ ) is formed, the molding surface layer 204 of the optical element molding die 201 in the third embodiment is formed by plasma film formation as shown in FIG. It is formed using the device 10.

First, the configuration of the plasma film forming apparatus 10 will be described.
As shown in FIG. 3, the plasma film forming apparatus 10 includes a vacuum chamber 11, a vacuum pump 12 and a turbo molecular pump 13 for depressurizing the inside of the vacuum chamber 11, and a plasma source 14 that generates plasma in the vacuum chamber 11. And a sample stage 21 for holding the object 22 (the mold base material 2 provided with the inclined film layer 3). The operations of the vacuum pump 12 and the turbo molecular pump 13 are controlled by a control device (not shown).

  The plasma source 14 includes a target 15, a trigger electrode 16, and an arc power source 17. The target 15 is a rod-shaped member made of metal Bi alone. The trigger electrode 16 is arranged with respect to the target 15 via an insulator (not shown), and the arc power source 17 is arranged coaxially with the central axis of the target 15 with respect to the trigger electrode 16 and the target 15 via a space. ing. A trigger power source 18 is connected to the target 15 and the trigger electrode 16, and an arc power source 19 is connected to the target 15 and the arc power source 17. The positive electrode and the negative electrode of the arc power source 19 are connected to the plasma source 14 via, for example, an 8800 μF electrolytic capacitor 20. The trigger power supply 18 is controlled by a control device (not shown) so as to apply a set voltage for a set time.

The sample stage 21 is provided in the vacuum chamber 11 and is disposed at a position where the object 22 is disposed on an extension line of the central axis of the target 15.
The vacuum chamber 11 is connected to a gas introduction pipe 24 for sending oxygen gas from the oxygen cylinder 23 into the vacuum chamber 11. The gas introduction pipe 24 is controlled by a control device (not shown) to be oxygen gas. A mass flow controller 25 is installed to control the flow rate.

Using the plasma film forming apparatus 10 having the above-described configuration, the surface of the object 22 (the surface of the inclined film layer 3 provided on the mold base material 2) is made of Bi oxide (Bi ₂ O ₃ ). A film is formed. More specifically, the object 22 is held on the sample stage 21. Further, the vacuum pressure in the vacuum chamber 11 is reduced to a predetermined pressure (for example, 1 × 10 ⁻⁴ Pa) by the vacuum pump 12 and the turbo molecular pump 13. Thereafter, oxygen gas is introduced into the vacuum chamber 11 from the oxygen cylinder 23 through the gas introduction pipe 24. At this time, the mass flow controller 25 is controlled by a control device (not shown) so that the flow rate of the oxygen gas becomes a predetermined flow rate (for example, 50 sccm), and the flow rate of the oxygen gas is set.

Thereafter, the arc power source 19 is set to a predetermined voltage (for example, 90V) to charge the electrolytic capacitor 20, and the trigger power source 18 is supplied with electric power for a predetermined voltage (3.5kV) and a predetermined time (10 μsec) by a control device (not shown). Apply. At that moment, a discharge occurs instantaneously between the trigger electrode 16 and the target 15 due to creeping discharge, and Bi that is slightly plasmatized is released from the surface of the target 15. As a result, the vacuum insulation between the target 15 and the arc power source 17 is broken to form an electric circuit, and arc discharge occurs between the target 15 and the arc power source 17 for about 600 μsec. By this arc discharge, Bi of the target 15 is turned into plasma, and plasma is emitted in the direction of the object 22 on the axis extension line of the target 15 by the magnetic field generated by the current flowing through the target 15 to react with oxygen in the atmosphere. As a result, Bi oxide (Bi ₂ O ₃ ) reaches the object to be processed 22 and adheres thereto. At this time, the amount of adhesion is very small, and it is such that Bi oxide (Bi ₂ O ₃ ) molecules are scattered on the surface of the object 22 to be processed by one discharge. Therefore, by repeatedly performing the above-described discharge treatment a plurality of times, the amount of Bi oxide (Bi ₂ O ₃ ) adhering to the object 22 is gradually increased, and a uniform film is obtained after passing through the island structure.

Here, an experimental result of an experiment in which a film of Bi oxide (Bi ₂ O ₃ ) is formed on the surface of the object 22 using the plasma film forming apparatus 10 will be described. In this experiment, the target surface state is an island-like structure made of Bi oxide (Bi ₂ O ₃ ), and the ratio of the total projected area to the surface area of the object 22 is 20%. The treatment was performed 500 times. Thereafter, was subjected to surface analysis of the object 22 using XPS, Bi oxide (Bi ₂ O ₃₎ was 21 atomic%. Moreover, when the surface of the to-be-processed object 22 was observed with the electron microscope, the spot pattern was confirmed. Thus, in the above-described experiment, the target surface state could be realized.

  According to the optical element molding die 201 of the present embodiment configured as described above, deposits adhere to the molded product (Bi-containing optical element) as in the first and second embodiments described above. It is possible to prevent the shape of the molding surface that has collapsed due to chemical erosion from being transferred to the molded product, and it is possible to produce a Bi-containing optical element that satisfies the optical characteristics.

  More specifically, a Bi-containing glass material is used in a nitrogen atmosphere having an oxygen concentration of 100 ppm or less using the optical element molding die 201 of the present embodiment having the above-described configuration provided with the inclined film layer 3 and the molding surface layer 204. When press molding was performed by heating to 550 ° C. below, good products could be obtained even with 2000 shots or more, and it was confirmed that the mold had sufficient durability.

[Fourth Embodiment]
Next, an optical element molding die 301 according to a fourth embodiment of the present invention will be described. The configuration of the optical element molding die 301 in the fourth embodiment will be described with reference to FIG. 1 which is also used in the description of the first to third embodiments.

The molding surface layer 304 of the optical element molding die 301 is a thin film made of Bi and B. The molding surface layer 304 can be formed on the surface of the gradient film layer 3 by a known method. For example, after the gradient film layer 3 is formed on the surface 2 b of the mold base material 2, a glass material containing 10 mol% or more of Bi and 3 mol% or more of B oxide (B ₂ O ₃ ) is formed in the gradient film layer 3. The glass material containing Bi and B oxide (B ₂ O ₃ ) described above and the mold base material 2 provided with the inclined film layer 3 are annealed in an air atmosphere. Thereby, a layer containing Bi and B is formed on the surface of the gradient film layer 3. Analysis by XPS after the annealing treatment confirms that Bi and B are formed on the surface of the gradient film layer 3.

  According to the optical element molding die 301 of the present embodiment configured as described above, deposits adhere to the molded product (Bi-containing optical element) as in the first to third embodiments described above. It is possible to prevent the shape of the molding surface that has collapsed due to chemical erosion from being transferred to the molded product, and it is possible to produce a Bi-containing optical element that satisfies the optical characteristics.

  More specifically, the Bi-containing glass material is used in a nitrogen atmosphere having an oxygen concentration of 100 ppm or less using the optical element molding die 301 of the present embodiment having the above-described configuration provided with the inclined film layer 3 and the molding surface layer 304. When press molding was performed by heating to 485 ° C. below, a good product could be obtained even at 1000 shots or more, and it was confirmed that it had sufficient mold durability.

Further, according to the optical element molding die 301 of the present embodiment having the above-described configuration, since the molding surface layer 304 contains B, it is composed only of Bi or Bi oxide (Bi ₂ O ₃ ). Compared with the molding surface layers 4, 104, and 204, the slidability between the optical element of the molded product and the molding surface 5 of the optical element molding die 301 is improved. Thereby, the press torque at the time of shaping | molding can be reduced.

  By performing a known heating / press molding method using the optical element molding dies 1, 101, 201, 301 of the first to fourth embodiments described above, an aspherical lens, a spherical lens, a free-form surface Various shapes of optical elements such as lenses and microlens arrays can be molded. In addition to Bi, this optical element includes glass forming components (P, B, Si, Ge, etc.), glass modifying components (Na, K, etc.), intermediate oxide components (Ba, etc.), etc. It may be contained within a range where the element does not devitrify.

The embodiments of the optical element molding die and the optical element according to the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present invention. It is. For example, the gradient film layer 3 in the first, second, and fourth embodiments described above is a single metal in the thickness D direction from the mold base material 2 side toward the molding surface layers 4, 104, 304 side. The inclined film gradually changes from Ta to its oxide Ta oxide Ta ₂ O ₅ (metal oxide), and the inclined film layer 103 in the third embodiment is formed from the mold base material 2 side. Although it is a graded film that gradually changes from Ir, which is a single metal, to Ir oxide, IrO ₂ (metal oxide), which is an oxide, in the direction of thickness D toward the surface layer 204 side, the present invention is not limited to this. It is not something. For example, from the die base material 2 side toward the molding surface layer 4, 104, 204, 304 side, the thickness gradually changes from Cr as a single metal to Cr oxide Cr ₂ O _{3 as} its oxide in the thickness D direction. It may be a graded film, or Al may be an oxide of Al from a single metal in the thickness D direction from the mold base material 2 side toward the molding surface layers 4, 104, 204, 304 side. _It may be a graded film that gradually changes to ₂ O ₃ , or from Si, which is a single metal in the thickness D direction from the mold base material 2 side toward the molding surface layer 4, 104, 204, 304 side. An inclined film that gradually changes to Si oxide SiO ₂ , which is an oxide, may be used.

In the above-described embodiments, Bi, Bi oxide (Bi ₂ O ₃ ), or forming of Bi and B is performed by a non-contact heating method using a furnace or a molding machine, a contact heating method, a plasma film forming method, or the like. Although the surface layers 4, 104, 204, and 304 are formed, the present invention may form a formed surface layer made of Bi or the like by another method. For example, various known methods such as vacuum deposition, reactive sputtering, ion plating, and electron beam irradiation can be used.

  In addition, in the range which does not deviate from the main point of this invention, it is possible to replace suitably the component in above-mentioned embodiment with a well-known component, and you may combine the above-mentioned modification suitably.

It is sectional drawing of the optical element shaping die for demonstrating embodiment of this invention. It is a graph showing the peak of the typical Auger analysis for demonstrating embodiment of this invention. It is a schematic diagram showing the plasma film-forming apparatus for describing embodiment of this invention.

Explanation of symbols

1, 101, 201, 301 Optical element molding die 2 Mold base material 2a Molding portion 3, 103 Inclined film layer 4, 104, 204, 304 Molding surface layer 5 Molding surface

Claims (4)

In an optical element molding die used for molding an optical element,
On the surface of the molding base side of the mold base material, a molding surface layer mainly composed of at least one of Bi and Bi oxide is formed on substantially the entire surface or the area of the surface of the total projected area. Is provided with an island-like structure such that the ratio to is 20% or more,
Between the mold base material and the molding surface layer, there is provided an inclined film layer that gradually changes from a single metal to an oxide of the metal from the mold base material side to the molding surface layer side. An optical element molding die characterized by comprising: The optical element molding die according to claim 1,
An optical element molding die, wherein the molding surface layer contains boron. The optical element molding die according to claim 1 or 2,
An optical element molding die, wherein the metal is any one of Cr, Ta, Ir, Al, and Si.   An optical element, which is molded using the optical element molding die according to any one of claims 1 to 3.

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