CN1733444A - Manufacturing method of molding die for optical element, molding die for optical element, and optical element - Google Patents

Abstract

The present invention relates to a mold for optical elements, which comprises a mold base made of a material having a thermal conductivity of 1-20W/mK and a film layer of an amorphous metal having a supercooled liquid region formed on the surface of the mold base, wherein the supercooled liquid region contains 20-80 mol% or more of at least 1 or more elements selected from the group consisting of Pt, Ir, Au, Pd, Ru, Rh, Fe, Co, Ni, Zr, Al, Ti, Cu, W, Mo, Cr, B and P, and the surface of the film layer is subjected to a predetermined processing to form an optical surface of the mold.

Description

Manufacturing method of molding die for optical element, molding die for optical element, and optical element

technical field

The present invention relates to a method of manufacturing a molding die for optical elements capable of shortening the molding cycle, a molding die for optical elements manufactured by the manufacturing method, and an optical element formed by the molding die for optical elements.

Background technique

According to the manufacturing method of molds for molding plastic optical elements generally practiced in the prior art, for example, Fe-based materials such as steel or stainless steel are used to manufacture blanks (primary processed products), and electroless plating called electroless nickel plating is performed on them. , forming an alloy coating of amorphous nickel and phosphorus with a thickness of about 100 μm. This coating is cut with an ultra-precision machining machine using a diamond tool to form a high-precision optical surface transfer surface for forming the optical surface of an optical element.

However, in recent years, optical elements with functions such as diffraction effects have been developed by adding microstructures with a height of several micrometers to the optical surface of optical elements. The fine structure of the optical surface of the optical element is obtained by forming a corresponding fine structure on the forming transfer surface of the forming mold in advance, forming the forming transfer surface and transferring it on the optical element material. Here, in order to form a fine structure with high precision by transfer such as injection molding and obtain an optical element having desired optical characteristics, it is necessary to embed an optical element material deep into the fine structure. However, in order to prevent the optical element material from adhering to the mold, the temperature of the mold is generally set lower than the temperature of the optical element material, so the surface of the optical element material in contact with the fine structure of the mold becomes colder, the viscosity increases, and there is a problem that the optical element material is difficult to embed into the mold. Problems deep in the microstructure. Therefore, in order to embed the optical element material deep into the microstructure, molding time is required to be increased by 1.5 times or more compared with the case of molding an optical element without a microstructure. Thus, since the number of optical elements produced per unit time is reduced, there arises a problem of causing an increase in the cost of the optical element.

In contrast, by forming the mold from a material with high heat resistance such as ceramics, even when it is in contact with the optical element material, the fluidity is improved by suppressing heat conduction, and the optical element material can be easily embedded in a short time to the depths of the microstructure.

Non-Patent Document 1: Mitsubishi Engineering-Plastics Corporation "Research on the transfer performance of heat-resistant molds made of ceramics" [online], June 2002, [retrieved on July 16, 2002], internet<URL;

http://www.enplanet.com/Company/00000006/Ja/Data/p019.html>

Patent Document 1: JP-A-2002-96335

Contents of the invention

However, according to this prior art method, a plated film is formed on the ceramic surface, and a fine structure is formed on the plated film by machining. However, in the manufacturing process, mechanical processing and electroless plating treatment are mixed together, which is complicated, and the delivery time is long, and the electroless plating treatment may not be stable, and the adhesion strength of the coating will be caused by the deviation or contamination of the blank composition. Inhomogeneity, or pinhole-like defects called sand holes will occur, or the optical surface transfer surface must be made in the coating thickness, so when the optical surface transfer surface is reprocessed, etc., there will be no allowance for the coating thickness , unfavorable conditions that make processing impossible, etc. In addition, there is a problem that the affinity between the plating layer and ceramics is relatively low, and problems such as peeling may occur when used for a long time. In particular, peeling will easily occur due to the pressure applied during the molding of the optical element.

The present invention has been made in view of the above-mentioned problems in the prior art, and its object is to provide a method of manufacturing a molding die for an optical element that has durability, can reduce the molding cycle time, and can mold an optical element with high precision. A molding die for the manufactured optical element and an optical element shaped by the die.

Description of drawings

FIG. 1 is a schematic configuration diagram of a sputtering apparatus for manufacturing a molding die for an optical element.

Fig. 2 is a schematic cross-sectional view of a molding die for an optical element.

Fig. 3 is a cross-sectional view of a set of dies including a molding die for an optical element, which is used to shape a lens as an optical element.

Fig. 4 is a perspective view showing an enlarged optical surface of a lens formed by a molding die for an optical element.

Fig. 5 is a schematic cross-sectional view of a mold used in a comparative test conducted by the present inventors.

Fig. 6 shows a schematic cross-sectional view of the filling state of the microstructured optical element material against the optical surface of the mold in a comparative test carried out by the present inventors.

Detailed ways

In order to achieve the above object, the preferable structure thereof is explained below.

The method of manufacturing a molding die for an optical element described in item 1 is characterized in that a film layer of an amorphous metal having a supercooled liquid region is formed on the surface of a mold base material having a heat conductivity of 1 to 20 W/mK , the supercooled liquid region contains more than 20-80mol% selected from Pt, Ir, Au, Pd, Ru, Rh, Fe, Co, Ni, Zr, Al, Ti, Cu, W, Mo, Cr, B, P At least one or more elements, by performing predetermined processing on the surface of the film layer, form the optical surface of the mold (referred to as the surface that is transferred to form the optical surface of the optical element to be formed).

For example, when attaching an electroless Ni plating layer on the surface of a mold base material and forming the optical surface of the mold on it, it takes a very long time of several weeks to obtain the necessary thickness of the coating film, and it takes a considerable amount of processing to form a mold. time.

On the other hand, as in the present invention, when forming a film layer of an amorphous metal having a supercooled liquid region on a mold base material, for example, by scattering the material particles from a material arranged at a distance from the mold base material, accumulation can be made. There is a film-forming process (especially sputtering or vapor deposition method) of an amorphous alloy with a supercooled liquid region to form a film layer, so that a film can be formed in a very short time, and compared with the plating method, a large Significantly shorten the manufacturing time of optical element molding dies (also simply referred to as molds).

In addition, for example, in the case of using ceramics as the above-mentioned mold base material, since ceramics are difficult-to-machine materials with high hardness, it is difficult to directly process the optical surface of the mold with a small structure by machining, so in the mold base material A film layer with good cutting performance is formed on the optical surface of the mold. But, in the electroless nickel plating (ENP film) film layer that uses as the mold optical surface material of optical element forming mold in the prior art, there is its poor compatibility with ceramics etc., the mold base material and film layer The problem of poor adhesion. In contrast, in the present invention, a film layer of an amorphous metal having a supercooled liquid region is formed on the mold base material, so the film can be formed within a shorter delivery date, and compared with the plating layer, it is relatively It has strong adhesion to the base material of the mold, and the cutting performance is equal to or better than that of the ENP film. By using the film layer of an amorphous metal with a supercooled liquid region, it can be provided in a short delivery date. A molding die for optical elements that has a fine structure formed on the optical surface of the mold and has a heat-resistant effect.

In addition, in the present invention, by using a film layer of an amorphous metal having a supercooled liquid region as a mold optical surface material of a molding die for an optical element, it can be easily formed into a very small film by diamond cutting after film formation. , smooth optical transfer surface. Especially when cutting fine structures such as diffraction grooves and DOE grooves with high precision and in large quantities, the high cutting performance of amorphous metals with supercooled liquid regions can prevent the tip of the fine tool from breaking In addition, the loss to the tool is also very small, so it is possible to cut while maintaining the diffraction effect while maintaining the important groove edge shape correctly.

In other words, in the present invention, since the mold base material formed of a material having a thermal conductivity of 1-20 W/mK is used, the heat-shielding effect of the optical element molding mold itself can be maintained. For example, when producing optical elements by molding, the upper and lower mold assembly steps, molten resin injection steps, mold pressurization and holding steps, cooling (resin solidification) steps, and optical element release steps are repeated as a cycle. The temperature of the forming chamber and the mold fluctuates periodically during the cycle. When the periodic change of the temperature is large, it is necessary to wait until the temperature of the mold is stable, especially when the microstructure (blaze shape, etc.) Raise the question. On the other hand, according to the present invention, by maintaining the thermal resistance effect of the mold and suppressing the fluctuation of the mold temperature in one cycle, the time for the mold temperature to stabilize can be shortened and the cycle time can be shortened. In addition, the lower the thermal conductivity, the higher the heat resistance effect of the mold, but on the other hand, when the thermal conductivity is too low, it will take time for the mold temperature to fluctuate, and the surface temperature of the mold is also prone to temperature unevenness. It is therefore preferred to choose a material with a thermal conductivity in the range of 1-20 W/mK.

In particular, according to the present invention, by using a substrate having a thermal conductivity of 1-20 W/mK as a mold substrate, the heat escaped from the optical element during molding of the optical element can be suppressed to a minimum. In the case of an existing mold base material using Fe-based raw materials, since the thermal conductivity is 50-90W/mK, heat is easy to escape from the optical element material, and it takes time to form a fine structure, but according to the present invention, Compared with the mold base material using Fe-based raw materials, the temperature of the optical element material can be maintained at a higher level for a longer period of time. The depth of the structure improves the forming transfer performance.

That is, in the present invention, by using an amorphous metal having a supercooled liquid region which is very suitable for microstructure machining as the material for the optical surface of the mold, and at the same time using it in combination with the base material of the mold to improve the shape transfer of the optical element A mold material with high performance, excellent thermal conductivity and low thermal conductivity can form high-performance optical elements with fine structures on the optical surface with high precision and high efficiency, and can be mass-produced.

Here, by including noble metal elements such as Pt, Ir, Au, Pd, Ru, and Rh in the film layer of the amorphous metal having a supercooled liquid region, it is possible to effectively improve the oxidation resistance and prevent fusion with the resin. Knot. In addition, by containing transition elements such as Fe, Co, Ni, Ti, W, Mo, and Cr, the hardness of the film layer can be increased, and the heat-resistant temperature of the film layer of the amorphous metal can be increased. The machinability of the film layer of the amorphous metal can be further improved by mixing Al and Cu with good machinability. By mixing B and P, the stability of the supercooled liquid region possessed by the film layer of the amorphous metal can be improved.

The method of manufacturing a molding die for an optical element described in claim 2 is characterized in that in the invention described in claim 1, the molding die for an optical element is used for molding an optical element having a diameter of 5 mm or less.

Especially when molding an optical element with a diameter of 5 mm or less, the heat capacity of the element itself is small, so the effect is increased by making the mold have a heat-resistant effect. When adding a sufficient heat resistance effect to the mold in this way, there are methods of using a material with a low thermal conductivity (20W/mK) as the base material of the mold, a method of using a material with a large specific heat, and increasing the size of the mold by increasing the shape of the mold. method of heat capacity, etc. By adding sufficient heat resistance effect to the mold, it can prevent the mold temperature from fluctuating sharply during the forming cycle, prevent the mold temperature from dropping significantly, and relatively interfere with the thermal response performance, so that the mold temperature becomes stable when passing through the forming cycle, and the result is not only Compared with the mold using Fe-based raw materials, the molding cycle time is shorter, and the molding transfer performance of the fine structure of optical elements can be obtained to the same degree or more.

The method for manufacturing a molding die for an optical element described in item 3 is characterized in that in the invention described in item 1 or 2, the thickness of the above-mentioned amorphous metal film layer formed on the surface of the above-mentioned mold base material is 10- 500μm, so the fine structure required for optical elements can be formed by, for example, diamond machining.

When the thickness of the film layer of the above-mentioned amorphous metal is less than 10 μm, when the optical surface of the mold is formed by cutting or grinding, the thickness of the film layer cut by one cutting or grinding process is 1-5 μm, so it can be cut or ground. The number of times is very limited, and the required shape of the optical surface of the mold can only be processed in one time, which increases the difficulty of processing. The thickness variation of the above-mentioned film layer is also more than ±5 μm at the time of film formation, so it is actually difficult to process the film thickness of the film layer to be 10 μm or less. On the other hand, the thicker the thickness of the film layer is, the more times it can be processed, and the burden on the processing process can be reduced. However, when the film layer of the above-mentioned amorphous metal is formed above 500 μm, the film stress gradually increases due to the thickness. Since peeling from the mold base material may occur, the thickness of the above-mentioned amorphous metal film layer is preferably in the range of 10 to 500 μm.

However, the processing step of the optical surface of the mold is not limited to machining such as cutting or grinding. It is also possible to take advantage of the easy transfer performance of the amorphous metal film layer with the supercooled liquid region, for example, to make a master mold with a fine structure, and use the forming transfer method to model from the master mold and form it on the optical surface of the mold. A fine structure corresponding to the shape of the rim of the optical element, etc. (see JP-A-2003-154529 and JP-A-2003-160343). According to this method, if one master mold is prepared, the mold can be easily produced by gradually transferring the surface shape, so it is not necessary to machine the optical surfaces of the mold one by one, and the mold manufacturing time can be greatly shortened.

The method for manufacturing a molding die for an optical element according to claim 4 is characterized in that in any one of the inventions described in claims 1 to 3, the thermal conductivity of the amorphous metal having the supercooled liquid region is 1- 20W/mK, so the film layer of amorphous metal with supercooled liquid region can also have heat resistance effect, which can improve the heat resistance effect of the mold as a whole.

The method of manufacturing a molding die for an optical element according to claim 5 is characterized in that in the invention according to any one of claims 1 to 4, the mold base material is formed of a ceramic material. Ceramic materials generally have a large specific heat and high heat retention effect, so the heat resistance effect of the mold can be improved.

The method for manufacturing a molding die for an optical element according to claim 6 is characterized in that in the invention described in claim 5, the above-mentioned mold base material is made of zirconia, alumina, Macorl (macorl), Macelite [Al ₂ O ₃ . K ₂ O · B ₂ O ₃ · F] any kind of ceramic formation. Ceramics such as alumina, zirconia, macol, and maserait have thermal conductivity in the range of 1 to 20 W/mK and are difficult to conduct heat, so they have a high heat resistance effect.

The method of manufacturing a molding die for an optical element according to claim 7 is characterized in that in any one of the inventions described in claims 1 to 4, the die base material is formed of an alloy, a polycrystalline metal, or a single crystal metal. When the mold base material is metal, the shape of the mold can be easily produced by cutting, grinding, etc., so compared with ceramic base materials, the lead time for mold manufacturing can be shortened, and the shape accuracy of the blank mold can be improved.

The method of manufacturing a molding die for an optical element according to claim 8 is characterized in that in the invention described in claim 7, the die base material is formed of any one of Inconel, Ti alloy, stainless steel alloy (SUS304, etc.). These materials are all metals, and the thermal conductivity is in the range of 1-20W/mK, so it is difficult to conduct heat conduction, has high heat resistance effect like ceramics, and is easy to process.

The method for manufacturing a molding die for an optical element according to claim 9 is characterized in that in any one of the inventions described in claims 1 to 8, the film layer of the amorphous metal having a supercooled liquid region is formed by PVD Process formation. The film layer of the amorphous metal having the supercooled liquid region is attached to the above-mentioned mold substrate through PVD (Physical Vapor Deposition) treatment, which can obtain a firm adhesion effect.

The method for manufacturing a molding die for an optical element according to claim 10 is characterized in that in the invention described in claim 9, the film layer of the amorphous metal having the supercooled liquid region is formed by sputtering, and thus is heated by plasma. The target element with the same composition as the amorphous metal with the required supercooled liquid region ejected by the high energy generated in the process hits the mold substrate to form an amorphous metal film layer, so the film layer has a high density and can be used firmly attached.

The method for manufacturing a molding die for an optical element according to claim 11 is characterized in that in any one of the inventions 1 to 8, the film layer of the amorphous metal having the supercooled liquid region is treated by ion plating. form. During the ion plating process, the elements of the same composition as the amorphous metal having a supercooled liquid region are evaporated in a high vacuum, and the evaporated stream is ionized. The ionized vaporized flow is accelerated toward the mold base material to which a negative voltage is applied, and can impact the mold base material with high energy to form a film and firmly adhere to it. At this time, the amorphous metal having a supercooled liquid region reacts with the gas and is very active chemically, so a film with good adhesion can be obtained at a relatively low reaction temperature.

The method for manufacturing a molding die for an optical element according to claim 12 is characterized in that in any one of the inventions 1 to 8, the film layer of the amorphous metal having the supercooled liquid region is deposited by a vapor deposition method. Formed so the film layer is uniform in thickness and adheres securely.

The method for manufacturing a molding die for an optical element according to claim 13 is characterized in that in any one of the inventions 1 to 8, the film layer of the amorphous metal having the supercooled liquid region is formed by CVD treatment. . The film layer of the amorphous metal with the supercooled liquid region is attached to the above-mentioned mold base through CVD (Chemical Vapor Deposition), and the gas having the same composition ratio as the amorphous metal with the required supercooled liquid region is passed. The chemical reaction of chemical elements will form a film layer, which can make the film thickness uniform, and the adhesion and transferability (つきまわり) is good and firm.

The method for manufacturing a molding die for an optical element according to claim 14 is characterized in that in any one of inventions 1 to 13, the amorphous material having a supercooled liquid region is formed on the surface of the die base material. Before the metal film layer, the surface roughness of the mold substrate surface is adjusted to the range of Ra=0.010-50 μm. By setting the surface roughness of the mold substrate surface at Ra=0.010-50 μm, the adhesion between the mold substrate and the amorphous metal film layer having the supercooled liquid region can be enhanced.

The method of manufacturing a molding die for an optical element according to claim 15 is characterized in that in the invention described in claim 14, the surface roughness is adjusted to a range of Ra=1-50 μm by a blasting process, so that it can be effectively adjusted. roughness. In rough surface processing using sand blasting, it is actually difficult to adjust Ra to 1 μm or less. In addition, when it exceeds 50 μm, the roughening of the surface of the mold base material is promoted, and when an amorphous metal film is formed thereafter, Film defects such as pinholes are likely to occur. Therefore, in the case of sand blasting, a surface roughness in the range of Ra=1-50 μm is appropriate.

The method for manufacturing a molding die for an optical element according to claim 16 is characterized in that in the invention described in claim 14, the surface roughness is adjusted to a range of Ra=0.010 to 50 μm by an etching step using an acid or alkaline solution. Therefore, the surface roughness can be controlled by temperature and time, so that the surface roughness can be adjusted stably.

The method of manufacturing a molding die for an optical element according to claim 17 is characterized in that in the invention described in claim 16, as the acid or alkaline solution, acetic acid, formic acid, hydrochloric acid, nitric acid, sulfuric acid, chromium etching solution, hydrogen Any solution of potassium oxide, sodium hydroxide, hydrocyanic acid, potassium ferricyanide, hydrogen peroxide, and aqua regia. By using these solutions, the surface roughness can be adjusted efficiently and stably.

The method of manufacturing a molding die for an optical element according to claim 18 is characterized in that in the invention described in claim 14, the surface roughness is adjusted to a range of Ra=0.010-50 μm by an etching step using a sputtering method. For example, if the mold base material is arranged in a vacuum, and the plasma discharge generated by approaching makes Ar particles impact the mold base material, thereby roughening the surface, the etching of the mold base material by other substances before and after etching can be reduced. Possibility of surface contamination.

The method of manufacturing a molding die for an optical element according to claim 19 is characterized in that in any one of the inventions 1 to 18, the film layer of the amorphous metal having a supercooled liquid region and the A functional film with a thickness of 0.01 μm-20 μm is formed between the mold substrates. The film is composed of noble metal element groups such as Pt, Ir, Pd, Au, Ru, Rh, Ag and Fe, Co, Ni, Cr, W, Ti, It is formed of any one element selected from the transition metal element group of Mo and Zr, or is formed of any combination of two or more elements.

By forming the above-mentioned functional film between the mold base material and the amorphous metal film layer having a supercooled liquid region, the adhesion between the mold base material and the film layer can be further improved .

The method for manufacturing a molding die for an optical element according to claim 20 is characterized in that in the invention described in claim 19, the film layer of the amorphous metal having a supercooled liquid region is formed between the film layer of the amorphous metal and the die base material. Form a film layer with a film thickness of 0.01 μm-20 μm, and the film layer is composed of aluminum oxide, chromium oxide, WC, silicon nitride, carbon nitride, TiN, TiAlN, zirconia, diamond, diamond-like carbon, carbon At least one component selected from the group, thereby forming a functional film.

By forming a film of the functional film formed of the above-mentioned material between the mold base material and the film layer of the amorphous metal having supercooled liquid, the gap between the mold base material and the film layer can be improved. In addition, the heat-blocking effect brought by the functional film, the oxidation protection effect of the mold base material brought by the functional film, and the shape protection of the mold brought by the high-hardness functional film can also be expected. effects etc.

The method of manufacturing a molding die for an optical element according to claim 21 is characterized in that in the invention according to claim 19 or 20, the functional film is formed by PVD treatment. When the functional film is adhered to the mold base through PVD treatment (Physical Vapor Deposition), it can be firmly attached.

The method for manufacturing a molding die for an optical element according to claim 22 is characterized in that in the invention described in claim 19 or 20, the functional film is formed by sputtering, whereby the functional film material is ejected by high energy generated by plasma. Impact the mold substrate to form a film layer, which can increase the density of the film layer and can be firmly attached.

The method of manufacturing a molding die for an optical element according to claim 23 is characterized in that in the invention according to claim 19 or 20, the functional film is formed by ion plating. Through the ion plating process, the material of the functional film is evaporated in a high vacuum, and the evaporated flow is ionized. Since this ionized evaporation flow is accelerated toward the mold base material to which a negative voltage is applied, a film can be formed by impacting the mold base material with high energy, and strong adhesion can be achieved. At this time, due to the reaction with the gas, the chemical properties of the functional film material are very activated, so a film with good crystallinity can be obtained at a relatively low reaction temperature.

The method of manufacturing a molding die for an optical element according to claim 24 is characterized in that in the invention described in claim 19 or 20, the functional film is formed by vapor deposition, so that the film layer has a uniform thickness and can be firmly adhered.

The method of manufacturing a molding die for an optical element according to claim 25 is characterized in that in the invention according to claim 19 or 20, the functional film is formed by CVD. The functional film is attached to the mold substrate through CVD (Chemiacl Vapor Deposition), and a film layer is formed through the chemical reaction of the gasified functional film material. The film layer has a uniform thickness and is firmly attached with good adhesion and transferability.

The method of manufacturing a molding die for an optical element according to claim 26 is characterized in that, in any one of the inventions of the 19th to 25th, before forming the functional film on the surface of the die base, the die base is The surface roughness of the material surface is adjusted to the range of Ra=0.010-50 μm. By setting the surface roughness of the mold substrate surface at Ra=0.010-50 μm, the adhesion between the mold substrate and the functional film can be enhanced.

The method of manufacturing a molding die for an optical element according to claim 27 is characterized in that in the invention described in claim 26, the surface roughness is adjusted to be in the range of Ra=1-50 μm by a blasting process, so that it can be effectively adjusted. roughness.

The method for manufacturing a molding die for an optical element according to claim 28 is characterized in that in the invention described in claim 26, the surface roughness is adjusted to a range of Ra=0.010 to 50 μm by an etching step using an acid or alkaline solution. Therefore, the surface roughness can be controlled by time, so that the surface roughness can be adjusted stably.

The method for manufacturing a molding die for an optical element according to claim 29 is characterized in that in the invention described in claim 28, as the acid or alkali solution, acetic acid, formic acid, hydrochloric acid, nitric acid, sulfuric acid, chromium etching solution, hydrogen Any solution of potassium oxide, sodium hydroxide, hydrocyanic acid, potassium ferricyanide, hydrogen peroxide, and aqua regia. By using these solutions, the surface roughness can be adjusted efficiently and stably.

The method of manufacturing a molding die for an optical element according to claim 30 is characterized in that in the invention described in claim 26, the surface roughness is adjusted to a range of Ra=0.010-50 μm by an etching step using a sputtering method. For example, if the mold base material is arranged in a vacuum, and the plasma discharge generated by approaching makes Ar particles impact the mold base material, thereby roughening the surface, the etching of the mold base material by other substances before and after etching can be reduced. Possibility of surface contamination.

The method for manufacturing a molding die for an optical element according to claim 31 is characterized in that in the invention according to any one of claims 1 to 30, the outer diameter of the molding die for an optical element is larger than the diameter of the optical element formed thereby. 1mm or more. That is, the outer diameter of the mold is larger than the diameter of the optical element to be produced by 1mm or more, so that when the volume of the mold substrate increases, the heat capacity of the entire mold also increases, and the heat resistance effect of the mold can be further increased. Usually the outer diameter of the mold is the same or almost the same as the diameter of the optical element produced (diameter is less than 1 mm), but in the case of the present invention, the outer diameter of the mold can be increased, the volume can be increased, and the heat capacity of the entire mold can be increased. .

The method for manufacturing a molding die for an optical element according to claim 32 is characterized in that in the invention according to any one of claims 1 to 31, an optical element is formed on the optical surface of the optical element molded by the optical element molding die. The axis-centered wheel belt structure can further improve the function of the optical element manufactured by the manufacturing method and molded by the molding die.

The method for manufacturing a molding die for an optical element according to claim 33 is characterized in that in the invention described in claim 32, the ring structure is a structure that imparts an optical path difference, so that the optical path produced by the manufacturing method can be further improved. Component The function of an optical element formed with a forming die. A so-called NPS (Non-Periodic Surface) structure is known as a structure for imparting an optical path difference.

The method for manufacturing a molding die for an optical element according to claim 34 is characterized in that in the invention described in claim 32, the ring structure is a micro-engraved diffraction structure with a zigzag cross section in the direction of the optical axis, so that it can be further improved The optical element manufactured by the above-mentioned manufacturing method is shaped by the molding die to perform the function of the optical element.

The method for manufacturing a molding die for an optical element according to claim 35 is characterized in that in the invention described in claim 32, the ring structure is a diffractive structure with a cross-section in the optical axis direction, so that the manufacturing method can be further improved. The optical element manufactured by the method uses a molding die to shape the optical element's function. DOE etc. are known as a stepwise diffraction structure.

The method for manufacturing a molding die for an optical element according to claim 36 is characterized in that in the invention according to any one of claims 1 to 35, the mold optical surface of the molding die for an optical element is formed only in an aspheric shape, and therefore An optical element having a high-precision aspheric surface can be manufactured at low cost.

The molding die for an optical element according to item 37 is characterized in that it is manufactured by the method for manufacturing a molding die for an optical element according to any one of items 1 to 36.

The optical element described in item 38 is characterized in that it is molded using the molding die for optical element described in item 37.

The optical element described in item 39 is characterized in that in the optical element described in item 38, a plastic material is used as a raw material.

The optical element according to item 40 is characterized in that in the optical element according to item 38, a glass material is used as a raw material.

The optical element according to claim 41 is characterized in that in the invention according to any one of claims 38 to 40, the optical element is a lens.

The optical element according to item 42 is characterized in that in the invention according to any one of items 38 to 41, the tire structure has a function to compensate for the change of the wavelength of the light source that irradiates light to the optical element. The function of changing the aberration (aberration) of the above-mentioned optical element can provide an optical element suitable for an optical pickup device for recording and/or reproducing information on an optical disk, for example.

The optical element according to item 43 is characterized in that in the invention according to any one of items 38 to 42, the ring structure has the function of compensating the change of aberration caused by the temperature change of the optical element, so that it can An optical element suitable for an optical pickup device for recording and/or reproducing information on, for example, an optical disc is provided.

The optical element described in item 44 is characterized in that in the invention described in any one of items 1 to 43, a plurality of protrusions or depressions are transferred and formed on the optical surface of the optical element, thereby further improving the optical element. Describe the function of the optical element. In addition, even if protrusions or depressions must be arranged at intervals of, for example, tens to hundreds of nanometers, they can be easily formed by transfer molding without machining. In addition, the term "protrusions or depressions" includes a mixture of both protrusions and depressions.

In recent years, attempts have been made to add new optical functions to optical elements by applying microstructures that are several times the wavelength of the light source used or smaller on optical surfaces. For example, the normal light-collecting function due to the refraction of the forming lens and the positive dispersion produced as a side effect at this time can be eliminated by the negative dispersion due to the diffraction caused by the diffraction groove provided on the surface of the aspheric optical surface. Elimination, so that the achromatization function that cannot be produced by only refraction is added to the single-lens lens optical element, and it is practically used in the pickup lens for optical discs compatible with DVD/CD. This is due to the use of the diffraction effect of the diffraction groove whose size is several tens of times the wavelength of the light passing through the optical element. This region that utilizes the diffraction effect of the structure sufficiently larger than the wavelength is called a scalar region. .

On the other hand, it is known that conical protrusions are densely formed on the surface of the optical surface at a fine interval of a fraction of the wavelength of light transmitted through the optical element, thereby exerting the function of suppressing light reflection. That is, the refractive index change that occurs at the interface with the air when the light wave enters the optical element does not instantaneously change from 1 to the refractive index of the medium as in conventional optical elements, but is due to the protrusions juxtaposed at fine intervals. The conical shape makes it change slowly, thereby suppressing light reflection. The optical surface forming such protrusions has a fine structure called a moth eye, and by juxtaposing finer structures than the wavelength of light at a period shorter than the wavelength, each structure no longer diffracts, but compared to Light waves act as an average refractive index. Such a region is generally referred to as an equivalent refractive index region. Such an equivalent refractive index region is described in, for example, C Vol. J83-C No. 3, pp. 173-181, March 2000, Journal of the Society for Electronics, Information and Communication.

Compared with the existing anti-reflection coating, if the fine structure of the equivalent refractive index region is used, the angle dependence and wavelength dependence of the anti-reflection effect are small, and a large anti-reflection effect can be obtained at the same time. Plastic molding, etc., can be made into optical surface and microstructure at the same time, so lens function and anti-reflection function can be obtained at the same time, without post-processing such as anti-reflection coating treatment after molding in the prior art, it also has advantages in production. Larger advantage and therefore eye-catching. In addition, when the fine structure of the equivalent refractive index region is directionally prepared relative to the optical surface, the optical surface can have strong optical anisotropy, and the existing technology can be obtained by molding crystals, etc. Birefringent optical elements produced by cutting crystals, and new optical functions can be added by combining refractive and reflective optical elements. The optical anisotropy in this case is called structural birefringence.

Between the above-mentioned scalar region and the equivalent refractive index region, there is a resonance region in which the diffraction efficiency changes rapidly depending on a slight difference in incident conditions. For example, when the groove width of the diffraction ring zone is narrowed, a phenomenon (abnormality) in which the diffraction efficiency decreases or increases sharply by several times the wavelength occurs. Utilizing the properties of this region, a resonant grating filter that reflects only the waveguide mode of a specific wavelength can be realized with a fine structure, and the same effect as a general interference filter can be realized, and the angle dependence is smaller.

The optical element according to claim 45 is characterized in that in the invention according to claim 44, the protrusions or depressions form a fine structure in an equivalent refractive index region. In addition, the interval between the protrusions or the recesses is preferably equal to or less than the wavelength of light transmitted through the optical surface of the optical element.

The optical element according to claim 46 is characterized in that in the invention according to claim 44 or 45, the protrusions or depressions form a fine structure that produces an antireflection effect. In addition, the interval between the protrusions or the recesses is preferably equal to or less than the wavelength of light transmitted through the optical surface of the optical element.

The optical element according to claim 47 is characterized in that in the invention according to any one of claims 44 to 46, the protrusions or depressions form a fine structure that produces a structural birefringence effect. In addition, the interval between the protrusions or the recesses is preferably equal to or less than the wavelength of light transmitted through the optical surface of the optical element.

The optical element according to claim 48 is characterized in that in the invention according to any one of claims 44 to 47, the protrusions or depressions form a fine structure of a resonant region. In addition, the interval between the protrusions or the recesses is preferably equal to or less than the wavelength of light transmitted through the optical surface of the optical element.

The optical element according to claim 49 is characterized in that in the invention according to any one of claims 44 to 48, the protrusions or depressions exist on a part of the optical surface of the optical element. On the optical surface of the optical element, protrusions or depressions of microstructures are formed in a plurality of shapes or configuration patterns, and by arranging these microstructures at a part of the optical surface, the optical surface can locally exhibit these features. Optical functions of microstructures. In this way, optical functions can be added to one light beam by partially or selectively applying optical functions based on the shapes or arrangement patterns of protrusions and depressions of the microstructure to the light beam passing through the optical surface. In this case, there is no need for fine-structured protrusions or depressions to exist on the entire surface of the optical surface of the optical element. That is, in the prior art, a plurality of optical elements need to be combined in order to exert predetermined optical functions, but if the optical elements of the present invention are used, predetermined optical functions can be exerted independently, the optical system can be further simplified, and the cost can be greatly reduced. . Furthermore, the optical element of the present invention can be easily mass-produced.

The optical element according to item 50 is characterized in that in the invention according to any one of items 44 to 49, there are protrusions or depressions having a plurality of shapes or arrangement patterns on at least a part of the optical surface of the optical element. .

The diffraction structure (diffraction ring belt) used in this specification refers to the relief (relief) that is formed into the ring belt of the substantially concentric shape centering on the optical axis by setting on the optical surface surface of an optical element (such as a lens), A so-called diffractive surface is formed, which has the effect of collecting or diverging the light beam through diffraction. For example, it is known that when the cross-section is viewed on a plane including the optical axis, each land has a sawtooth-like shape, and this diffraction structure includes such a shape. Diffraction ring belts are also called diffraction grooves.

When the present invention is applied, the ring structure, the juxtaposition of protrusions (or depressions), and the like are not related to the shape or arrangement period of each fine structure. Even if it is any kind of fine structure, as long as it is implemented for the purpose of adding a new function to the optical element, the molding die for the optical element or the optical element formed therefrom are also included in the scope of the present invention. However, as a newly added function, it is not limited to reducing aberrations. Even in the case of intentionally increasing the aberration corresponding to the characteristics of the optical system, it is also included in the scope of the present invention that the aberration is implemented so as to approach the ultimate ideal aberration.

The effect of the invention

According to the present invention, it is possible to provide a method of manufacturing a molding die for an optical element that has durability, reduces molding cycle time, and can shape an optical element with high precision, an optical element molding die manufactured thereby, and an optical element molded by the die .

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are diagrams showing a manufacturing process of a molding die for an optical element. First, a cylindrical mold base 10 is produced. As the material of the mold base 10, specifically, as a material having a thermal conductivity of 20 W/Km or less, zirconia, alumina, macol, maselite [Al ₂ O ₃ ·K ₂ O ·B ₂ O ₃ · F], Inconel alloy, Ti alloy, stainless steel alloy (SUS304), etc. As an example, when using a zirconia base material (NPZ-1), first, zirconia powder is sintered into a shape similar to that of the mold base material (hot pressing). Thereafter, the base material of the blank mold is ground to obtain the accuracy of the outer dimension. In addition to the optical element forming transfer surface of the processing mold (hereinafter referred to as the optical surface of the mold), the outer peripheral part and the end surface are cut using a diamond tool, and a grinding process is performed using a diamond tool. In this case, the processing accuracy of the outer peripheral portion is preferably such that the shape accuracy is 2 μm or less, and the surface roughness is Ra 100 nm or less.

On the processed mold base material 10, a functional film Cr with a film thickness of 0.01-50 μm is formed on the optical surface of the mold. Examples of the film forming apparatus include a sputtering apparatus, a vapor deposition apparatus, ion plating, CVD, and the like. When forming a functional film on a sputtering device, the film forming conditions vary depending on the device, but as an example, in an Ar atmosphere of 0.1 Pa, RF300W, and the distance from the target to the optical surface of the mold is set to 90 mm. According to different devices, the film forming speed can also be adjusted to generally vary within the range of 1 μm/h-20 μm/h through the distance.

The major function of the functional film is to enhance the adhesion between the mold base material and the film layer of amorphous metal having a supercooled liquid region formed in a later step. In particular, when an amorphous metal film layer having a supercooled liquid region is formed on a ceramic material such as zirconia, it is preferable to provide a functional film. In the case of a non-functional film, where a film layer of an amorphous metal having a supercooled liquid region is formed on a zirconia mold substrate, the adhesion of the film is measured by an adhesive tape peel test, and the adhesion is 50gf When the functional film Cr is formed with a film thickness of 0.01-1μm, the adhesion can be increased to more than 1000gf. In the subsequent process, the cutting process is used to form the optical surface of the mold or when it is used as a forming mold. , can prevent the molding resin and the optical surface of the mold from sticking to cause the peeling of the amorphous metal with the supercooled liquid region.

The inventors of the present invention will describe the adhesive tape peeling test carried out. The so-called adhesive tape peeling test refers to attaching an adhesive tape on the surface of the film layer, peeling it off quickly and strongly, and recording the maximum tensile load at the time of peeling as the film layer. Adhesion was evaluated. The upper limit of the adhesive force for this measurement can be determined by the adhesive force strength of the test tape. The double-sided tape used in the above evaluation test is a tape having an adhesive force of 1000 gf in a plane of about 30 mm ² , so the upper limit of the measurable adhesive force is 1000 gf. In addition, use a sharp knife tip to form streaks on the film layer before attaching the scallops, and form a square with a side length of 6-7mm until the original surface. Afterwards, when the test is carried out, it can be judged more clearly.

After the desired functional film layer is obtained, a film-forming apparatus such as sputtering (see FIG. 1 ) is used to form a film layer of an amorphous metal having a supercooled liquid region. The mold base material 10 was mounted on a film forming apparatus of metallic glass (also called amorphous metal with supercooled liquid) shown in FIG. 1 . More specifically, in FIG. 1 , in the processing chamber P covered by the housing 200, a target support table 201 for supporting the target T is placed, and a mold base is arranged and held on it so as to correspond to the base surface. Sample holder 202 for material 10. A cooling pipe is formed inside the target holding table 201, and the external control device 203 is passed through the cooling pipe, so that cooling water for temperature adjustment can be circulated.

In addition, the process chamber P is connected to a turbomolecular pump 204 via a valve V1, and the turbomolecular pump 204 is connected to a rotary pump 205 via a valve V2. Ar molecules are contained in the processing chamber P and are attracted by the two pumps 204 and 205 to form a pressure of about 10 ⁻¹ to several Pa.

The film forming conditions vary depending on the film forming conditions such as the film thickness and the equipment. As an example, RF500W in an Ar atmosphere of 0.5 Pa, and the distance from the target to the sample to be filmed, that is, the optical surface of the mold, can be mentioned. The distance is set to 90mm. Depending on the device, the film forming speed can be changed in the range of 1 μm/h to 20 μm/h by adjusting the distance. If the closer to the sample, the higher the film-forming rate, problems such as coarsening of the film-forming film particles will occur, so adjustment is required. The confirmation of the amorphous state in the test of this method of film formation can be confirmed by using DSC (thermal flux differential scanning calorimetry device), observing the endothermic reaction generated when the amorphous state phase transfers to the supercooled liquid region, or by X-ray diffraction Observation with a device revealed a pattern in which peaks were not seen at all due to the crystal structure peculiar to the amorphous state, and thus confirmed. This method makes it easier to form a metallic glass film on the optical surface of a molding die for optical applications, compared to conventional methods for producing a metallic glass body.

The raw material mold having the amorphous metal film layer forming process having the supercooled liquid region was subjected to a cutting process using a diamond tool, and a grinding process using a diamond tool, except for the mold optical surface.

Diamond cutting uses a single crystal diamond tool T shown by the dotted line in Fig. 2, and is cut one by one by an ultra-precision turntable (not shown), so the process is basically the same as the conventional manufacturing method of a mold using electroless nickel plating. However, compared with the prior art, the optical surface MGa of the mold and the transfer surface MGb of the geometric reference surface MGb can be rapidly and densely formed by PVD or CVD, without the need for electroless plating, so pinholes, etc. will not occur It can be said that it has more excellent characteristics because of the defect, the processing delivery date is accelerated, and because the cutting performance is very good, the wear on the tool is small, and the shape can be easily formed by cutting.

However, the machining process of the optical surface of the mold is not limited to diamond cutting. By utilizing the easy transfer performance of the amorphous metal film layer with the supercooled liquid region, it is also possible to produce, for example, a master mold with a fine structure, which is modeled from the master mold by the forming transfer method, and formed on the optical surface of the mold. A fine structure corresponding to the shape of the rim of the optical element, etc. (see JP-A-2003-154529 and JP-A-2003-160343). According to this method, if one master mold is prepared, the mold can be easily produced by gradually transferring the surface shape, so it is not necessary to machine the optical surfaces of the mold one by one, and the mold manufacturing time can be greatly shortened.

In this case, the processing accuracy of the outer peripheral portion is preferably dimensional accuracy of 2 μm or less and surface roughness of Ra 100 nm or less. When the mold base material is a relatively hard and brittle difficult-to-machine material such as zirconia, the dimensional accuracy can be obtained through the grinding process. After completion of this outer peripheral portion processing step, predetermined processing is performed on the mold optical surface MGa. That is, the mold optical surface MGa has a supercooled liquid region by cutting the amorphous metal film layer with a diamond tool to obtain a mold optical surface shape having a fine structure and/or an aspheric shape. Preferably, the shape accuracy is below 50nm, and the surface roughness is below Ra5nm. In addition, predetermined processing is not limited to mechanical processing. That is, in the mold peripheral processing step, when the mold base material is ceramics, the film layer or functional film layer of the amorphous metal having the supercooled liquid region attached to the outer peripheral part may be scraped off by the grinding process, and the ceramic base material may be removed from the ceramic base material. The material is peeled off to obtain the peripheral dimensional accuracy. When the ceramic substrate is to be peeled off, even when the mold is in a structure that vibrates up and down to take out the molded product during the molding of the optical element, since the hardness of the ceramic substrate has a small coefficient of friction, it can also suppress the friction between the parts around the mold. Scratching between parts can be prevented, and the operation can be reliably performed, and the wear of the mold or the parts around the mold that are subject to vibration can be suppressed. However, whether or not the outer peripheral portion is peeled from the base material is not involved in the present invention.

As described above, an amorphous metal having a supercooled liquid region with a film thickness of 10-500 μm can be formed on the mold optical surface MGa using a mold material having a thermal conductivity of 1-20 W/mK on the mold base 10. film layer to obtain a molding die 10 ′ for optical elements used to shape optical elements with a diameter of 5 mm or less. In addition, it is preferable that the outer diameter φ (Fig. 2) of the molding die 10' for an optical element is larger than the diameter of an optical element molded therefrom by 1 mm or more.

Fig. 3 is a cross-sectional view of a set of molds including an optical element molding die 10' for molding a lens as an example of an optical element. The optical element molding die 10' on which the amorphous alloy MG is formed as described above and the optical element molding die 11' on which the amorphous alloy MG' is formed are separated from each other by the mold optical surfaces MGa and MGa'. and the geometric dimension reference surface transfer surfaces MGb, MGb' are inserted into the mold cover molds 13, 14 in such a manner that they face each other, and are inserted into the molding mold 10' for optical elements in the same way as the usual injection molding from the unshown gate. The molten plastic material PL is injected between , 11' and further cooled to obtain the desired shape of the lens.

FIG. 4 is a cross-sectional view showing an enlarged example of an optical surface of a lens formed by such a molding die for an optical element. In FIG. 4( a ), as an example of a plurality of protrusions on the optical surface of the lens, many fine cylinders C form a matrix-like structure (an example of a fine structure in an equivalent refractive index region). For example, when such an objective lens is used as a lens of an optical pickup device for DVD recording/reproducing, the light passing through the lens is around 650 nm. Therefore, when the distance Δ between the fine cylinders C is 160 nm, light incident on the objective lens is hardly reflected, and an objective lens having an extremely high light transmittance can be provided.

In FIG. 4(b), as an example of a plurality of protrusions on the optical surface of the lens, a plurality of fine triangular pyramids T are formed at an interval Δ, which has the same remarkable effect as in FIG. 4(a). As the interval Δ, it is preferable that it is 0.1 to 0.2 μm or less since scattering can be reduced. In FIG. 4( c ), as an example of a plurality of protrusions, a plurality of fins F are formed at intervals Δ on the optical surface of the lens (an example of a fine structure for constructing double irradiation). The length of the fins F is longer than the wavelength of the transmitted light (650 nm or more in the above example). The lens having this configuration transmits light having a vibrating surface in a direction along the fin F, but does not transmit light in a direction intersecting the fin, and has a so-called polarization effect. In FIG. 4( d ), on the optical surface of the lens as an example of a ring structure centered on the optical axis, a micro-engraved diffraction ring D with a zigzag cross-section in the direction of the optical axis is formed. Aberration compensation and temperature compensation, which are effects corresponding to the shape, are described in detail in, for example, JP-A-2001-195769 concerning this diffraction ring D, and therefore descriptions thereof are omitted below. As other tire structures, NPS, DOE, etc. can be formed. In addition, in Fig. 4 (a)-(c), in order to simply show the example of setting these protrusions on the plane, but also can make its bottom surface have the curved surface with suitable curvature such as spherical surface or aspheric surface, on this curved surface settings on the

Fig. 5 is a schematic cross-sectional view of a mold used in a comparative test conducted by the present inventors. The form of each mold is explained. Fig. 5 (a): embodiment 1: the film layer of ceramics (mold substrate) + metallic glass, Fig. 5 (b): embodiment 2: the film layer of ceramics (mold substrate) + functional film + metallic glass, Fig. 5(c): Comparative Example 1: Metal (mold base material) + coating layer, Figure 5(d): Comparative Example 2 (equivalent to Non-Patent Document 1): Ceramic (mold base material) + coating layer , Figure 5(e): Comparative Example 3 (equivalent to Patent Document 1): Ceramic (mold base material) + metal layer + coating layer.

The inventors of the present invention performed comparative evaluation using the above molds. The evaluation results are shown in Table 1.

Table 1

Comparison Chart Advantages of Optical Component Forming Advantages in mold making Transfer performance Durability Die shape change after 10,000 impacts machinability During mold processing Example 1 ◎ ○ ◎ ◎ ◎ Example 2 ◎ ○～◎ ◎ ◎ ◎ Comparative example 1 ○ ◎ ○ ○ ○ Comparative example 2 △ △～× ◎ ○ △ Comparative example 3 ◎ △～× ◎ ○ △

In Table 1, the transfer performance of the mold refers to an evaluation of how accurately an optical element having a diffractive structure used in an optical pickup device is transferred satisfactorily. In addition, since the optical element used in the optical pickup device for DVD/CD and the optical element used in the optical pickup device for BD (Blu-ray Disc)/HD DVD, the wavelength of the laser light is different, and BD ( Blu-ray Disc)/HD DVD optical pickups used in optical devices have finer structures, requiring higher transfer performance. Here, the evaluation results mean the following meanings.

◎: Very good transfer performance

○: Good transfer performance

△: transfer performance is average

×: poor transfer performance

In Table 1, the durability of the mold was evaluated based on the number of impacts at which the film layer peeled off during molding. Here, the evaluation result has the following meanings.

◎: More than 10,000 impacts can be formed

○: Thousands of impacts can be formed

△: Hundreds of impacts can be formed

×: Formable within dozens of impacts

In Table 1, the shape change of the mold is evaluated by comparing the shape change of the mold after forming with the initial value, such as 10 impacts, 100 impacts, 1000 impacts, 5000 impacts, and 10000 impacts per unit impact number, Here, the evaluation result has the following meanings.

◎: The shape does not change

○: There is a change in shape, but the deformation does not become a problem in practical use

△: Non-negligible deformation occurs, but it is possible to respond to changes in molding conditions

×: Non-negligible deformation occurred, and even if the molding conditions were changed, it could not be used as a mold for optical elements.

In Table 1, the cutting performance of the dies was evaluated based on the roughness of the surface after cutting with a diamond tool. Here, the evaluation result has the following meanings.

◎: Ra less than 1nm

○: Ra is 1-10nm

△: Ra is 10-50nm

×: Ra exceeds 50nm

In Table 1, the processing period of the mold was evaluated in terms of the total time spent in mold production. Here, the evaluation result has the following meanings.

◎: The processing period of the mold is within several weeks.

○: The mold processing period is about 1 to 2 months

△: The processing period of the mold exceeds 2 months

When the evaluation results were examined, it was found that Examples 1 and 2 obtained very good results in terms of transfer performance compared with Comparative Examples 1 and 2. In addition to forming the overall shape, it is important to transfer the shape of the optical element such as a DVD compatible lens or a BD (Blu-ray)/HD DVD lens, whether the shape of the diffraction groove provided on the optical surface is transferred. Can be implemented with good precision, the transfer performance is the most effective for the performance of the optical element. It can be seen from the comparison results that, in the case of Examples 1 and 2, the depression of the groove portion (refer to FIG. 6, described later) is reduced by 1/2 to 1/4. And the transfer of the microstructure in the optical element for BD/HD DVD with further reduced height or pitch is difficult to carry out practically with the structure of Comparative Example 2, but Examples 1 and 2 are all good.

Fig. 6 shows a schematic cross-sectional view of the filling state of the microstructured optical element material with respect to the optical surface of the mold in a comparative experiment carried out by the present inventors. Figure 6(a) uses Fe-based material as the mold base material, on which a film is formed by electroless nickel plating to form a micro-sculpture microstructure (10 μm pitch, 1 μm height), which is used as a comparative example. Figure 6(b) uses zirconia as the mold base material, on which a film layer of amorphous metal with a supercooled liquid region is formed, and a micro-carved microstructure is also formed, which is used as an example.

Use these molds to inject resin, cut off the fine structure before demolding, and use an electron microscope to observe whether the deepest part of the micro-groove enters the resin for transfer. When the micro-carved microstructure made on the optical surface of the mold is transferred to the optical element, the molten resin does not enter the deep bottom of the micro-carved groove of the microstructure, so the transfer is not good, as shown in Figure 6(a) In the case where the surface shape of the optical element transferred from the micro-grooves on the optical surface of the mold produces a poorly transferred portion, this phenomenon is called sinking. By measuring the length Δ of the indentation in the pitch direction ( FIG. 6( a )), it can be used as an index for evaluating the fine shape transfer performance of the optical element. In the comparative example shown in Figure 6 (a), the depression is 1-2 μm, in the embodiment shown in Figure 6 (b), the depression is below 0.5 μm, opposite to the depression of the comparative example, the embodiment This effect can be confirmed by reducing the indentation of 1/2-1/4.

With respect to durability, Examples 1 and 2 obtained very good results relative to Comparative Examples 2 and 3. In particular, both Examples 1 and 2 were better than the case where peeling occurred at the predetermined number of impacts in the configuration of Comparative Example 2. Furthermore, compared with Example 1, Example 2 exhibited 20 times or more durability. On the other hand, as shown in the comparative example, it is known that the combination of the ceramic base material and the plating layer has poor compatibility, and the film layer is easily peeled off. In particular, peeling tends to occur when thermal shock is repeatedly applied.

As for the change in mold shape, Comparative Examples 2, 3 and Examples 1, 2 are all good. Effective in suppressing changes in mold shape when using relatively hard materials such as ceramics as the mold base.

As for the cutting performance, compared to Comparative Examples 1-3, Examples 1, 2 obtained good results. The film layer of the amorphous metal having the supercooled liquid region is densely formed by the sputtering process, so the machinability is very good, especially the machinability of fine structures and the like is excellent.

As for the machining period of the mould, compared to Comparative Examples 1-3, Examples 1, 2 obtained good results. Formation of an amorphous metal film layer with a supercooled liquid region by sputtering can be completed only by a simple process called machining, which is comparable to other inventions that require ceramic dissolution or coating film formation on a mold base material. Compared, the number of times can be effectively reduced, the processing period of the mold can be shortened, and the cost of mold manufacturing can be reduced.

Claims (55)

1. A molding die for an optical element, characterized by having a mold base material formed of a material with a thermal conductivity of 1-20 W/mK and an amorphous metal having a supercooled liquid region formed on the surface of the mold base material The film layer, the supercooled liquid region contains more than 20-80mol% selected from Pt, Ir, Au, Pd, Ru, Rh, Fe, Co, Ni, Zr, Al, Ti, Cu, W, Mo, Cr, B , at least one element of P, The optical surface of the mold is formed by performing predetermined processing on the surface of the film layer. 2. The molding die for an optical element according to claim 1, wherein the die base material is formed of a ceramic material. 3. The molding die for optical elements according to claim 2, wherein the mold base material is made of zirconia, alumina, macol, maselite [Al ₂ O ₃ ·K ₂ O ·B ₂ O ₃ · F] any kind of ceramic formation. 4. The molding die for an optical element according to claim 1, wherein the die base material is formed of alloy, polycrystalline metal or single crystal metal. 5. The molding die for an optical element according to claim 4, wherein said die base material is formed of any one of Inconel, Ti alloy and stainless steel alloy. 6. The molding die for an optical element according to claim 1, wherein said mold base The surface roughness of the surface is adjusted to be in the range of Ra=0.010-50 μm. 7. The molding die for an optical element according to claim 6, wherein the surface roughness is adjusted to a range of Ra=1-50 μm through a sandblasting process. 8. The molding die for an optical element according to claim 6, wherein said surface roughness is adjusted to a range of Ra=0.010-50 [mu]m by an etching process using an acid or alkaline solution. 9. The molding die for an optical element according to claim 6, wherein acetic acid, formic acid, hydrochloric acid, nitric acid, sulfuric acid, chromium etching solution, potassium hydroxide, sodium hydroxide, hydrogen Any solution of cyanic acid, potassium ferricyanide, hydrogen peroxide, or aqua regia. 10. The molding die for an optical element according to claim 6, wherein said surface roughness is adjusted to a range of Ra=0.010-50 [mu]m by an etching step using a sputtering method. 11. The molding die for an optical element according to claim 1, wherein the thickness of the amorphous metal film layer formed on the surface of the die base material is 10-500 μm. 12. The molding die for an optical element according to claim 1, wherein the thermal conductivity of said amorphous metal having a supercooled liquid region is in the range of 1 to 20 W/mK. 13. The molding die for an optical element according to claim 1, wherein the film layer of the amorphous metal having the supercooled liquid region is formed by PVD treatment. 14. The molding die for an optical element according to claim 1, wherein the film layer of the amorphous metal having the supercooled liquid region is formed by sputtering. 15. The molding die for an optical element according to claim 1, wherein the film layer of the amorphous metal having the supercooled liquid region is formed by ion plating. 16. The molding die for an optical element according to claim 1, wherein the film layer of the amorphous metal having the supercooled liquid region is formed by vapor deposition. 17. The molding die for an optical element according to claim 1, wherein the film layer of the amorphous metal having the supercooled liquid region is formed by CVD. 18. The molding die for optical elements according to claim 1, characterized in that there is a layer of amorphous metal with a thickness of 0.01 μm to 20 μm between the film layer of the amorphous metal having the supercooled liquid region and the mold base material. Functional film, the film is selected from the noble metal element group of Pt, Ir, Pd, Au, Ru, Rh, Ag and the transition metal element group of Fe, Co, Ni, Cr, W, Ti, Mo, Zr Formed by one element, or formed by any combination of two or more elements. 19. The molding die for an optical element according to claim 1, wherein a film thickness of 0.01 μm- A film layer of 20 μm, and the film layer has at least 1 component, thus forming a functional film. 20. The molding die for optical elements according to claim 18, wherein said functional film is formed by PVD treatment. 21. The molding die for an optical element according to claim 18, wherein said functional film is formed by sputtering. 22. The molding die for optical elements according to claim 18, wherein said functional film is formed by ion plating. 23. The molding die for optical elements according to claim 18, wherein said functional film is formed by vapor deposition. 24. The molding die for optical elements according to claim 18, wherein said functional film is formed by CVD. 25. The molding die for an optical element according to claim 1, wherein an optical element having a diameter of 5 mm or less is molded. 26. The molding die for an optical element according to claim 25, wherein the outer diameter of the molding die for an optical element is larger than the diameter of an optical element to be molded therefrom by 1 mm or more. 27. The molding die for optical element according to claim 25, wherein a ring structure centering on the optical axis is formed on the optical surface of the optical element molded by the molding die for optical element. 28. The molding die for an optical element according to claim 27, wherein said tire has a structure for imparting an optical path difference. 29. The molding die for optical elements according to claim 27, characterized in that the cross-section of the ring structure in the direction of the optical axis is a zigzag micro-engraved diffractive structure. 30. The molding die for an optical element according to claim 27, wherein the cross-section of the ring structure in the direction of the optical axis is a stepped diffractive structure. 31. The molding die for an optical element according to claim 1, wherein the optical surface of the molding die for an optical element is formed of only an aspheric shape. 32. An optical element, characterized by being molded using the molding die for an optical element according to claim 1. 33. Optical element as claimed in claim 32, characterized in that plastic material is used as raw material. 34. The optical element according to claim 32, wherein a glass material is used as a raw material. 35. The optical element of claim 32, wherein the optical element is a lens. 36. The optical element according to claim 32, characterized in that the optical element forms a wheeled structure on the optical surface, and the wheeled structure has a compensation effect caused by a change in the wavelength of the light source that irradiates light relative to the optical element. A function of the aberration variation of the optical element. 37. The optical element according to claim 32, characterized in that said optical element forms a wheeled structure on an optical surface, said wheeled structure has a function of compensating for said optical element due to temperature changes relative to said optical element. A function of aberration variation. 38. The optical element according to claim 32, wherein a plurality of protrusions or depressions are formed by transferring on the optical surface of the optical element. 39. The optical element according to claim 38, characterized in that said protrusions or depressions form a fine structure in an equivalent refractive index region. 40. The optical element according to claim 38, characterized in that said protrusions or depressions form fine structures that produce an anti-reflection effect. 41. The optical element according to claim 38, wherein said protrusions or depressions form fine structures that generate structural birefringence. 42. The optical element according to claim 38, wherein said protrusions or depressions form fine structures that generate resonance regions. 43. The optical element according to claim 38, wherein said protrusion or depression exists on a part of the optical surface of said optical element. 44. The optical element according to claim 38, wherein there are protrusions or depressions having at least various shapes or configuration patterns on a part of the optical surface of the optical element. 45. A method for manufacturing a forming mold for an optical element, characterized in that an amorphous metal film layer having a supercooled liquid region is formed on a mold base material having a thermal conductivity of 1-20 W/mK, the The supercooled liquid region contains more than 20-80mol% of at least 1 selected from Pt, Ir, Au, Pd, Ru, Rh, Fe, Co, Ni, Zr, Al, Ti, Cu, W, Mo, Cr, B, P More than one kind of elements, by performing predetermined processing on the surface of the film layer, the optical surface of the mold is formed. 46. The method of manufacturing a molding die for an optical element according to claim 45, wherein the film layer of the amorphous metal having the supercooled liquid region is formed by PVD treatment. 47. The method of manufacturing a molding die for an optical element according to claim 45, wherein the film layer of the amorphous metal having the supercooled liquid region is formed by sputtering. 48. The method of manufacturing a molding die for an optical element according to claim 45, wherein the film layer of the amorphous metal having the supercooled liquid region is formed by ion plating. 49. The method of manufacturing a molding die for an optical element according to claim 45, wherein the film layer of the amorphous metal having the supercooled liquid region is formed by vapor deposition. 50. The method of manufacturing a molding die for an optical element according to claim 45, wherein the film layer of the amorphous metal having the supercooled liquid region is formed by CVD. 51. The method for manufacturing a molding die for optical elements according to claim 45, wherein the film layer of the amorphous metal having the supercooled liquid region is formed on the surface of the mold base material, and the The surface roughness of the mold substrate surface is adjusted to be in the range of Ra=0.010-50 μm. 52. The method of manufacturing a molding die for an optical element according to claim 45, wherein said surface roughness is adjusted to a range of Ra=1-50 μm by a sandblasting process. 53. The method of manufacturing a molding die for an optical element according to claim 51, wherein said surface roughness is adjusted to a range of Ra=0.010-50 [mu]m by an etching step using an acid or alkali solution. 54. The method of manufacturing a molding die for an optical element according to claim 53, wherein as the acid or alkaline solution, acetic acid, formic acid, hydrochloric acid, nitric acid, sulfuric acid, chromium etching solution, potassium hydroxide, hydroxide Any solution of sodium, hydrocyanic acid, potassium ferricyanide, hydrogen peroxide, or aqua regia. 55. The method of manufacturing a molding die for an optical element according to claim 51, wherein said surface roughness is adjusted to a range of Ra=0.010-50 [mu]m by an etching step using a sputtering method.

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