JP3067150B2 - Optical device manufacturing equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical element manufacturing apparatus for forming an optical thin film on a plastic substrate based on electron beam heating evaporation of a vacuum evaporation method.

[Conventional technology]

Optical thin films formed on plastic substrates can be classified into antireflection films, reflection-enhancing films, reflection films, filters, polarizing filters, phase plates, etc., based on their functional aspects, and most of them are structurally designed based on optical theory. Is done. Depending on the design, there are a single-layer film and a multi-layer film.

This optical thin film is composed of SiO, SiO ₂ , Zr
A dielectric such as O ₂ , MgF ₂ , TiO ₂ , CeO ₂ , ZnS, Al ₂ O ₃ , ZnO, or MgO, or a metal or metalloid such as Al, Ag, Au, or Ge is used.

Since the optical thin film is generally as thin as 0.01 to 10 μm, it is generally formed by vacuum deposition, sputtering, ion plating, or the like. In the case of vacuum deposition, there are two types of means for heating the coating material: resistance heating and electron beam heating. In resistance heating, a material with a low melting point, such as Si
Only O _x (1 ≦ X <2) can be deposited, whereas electron beam heating uses materials with high melting points, such as SiO ₂ , ZrO ₂ , TiO ₂ ,
Mo, W, Ta, Al ₂ O ₃ can also be deposited.

[Problems to be solved by the invention]

However, in the electron beam heating described above, an electron beam is applied to a coating material (especially an oxide) to heat and evaporate the material. However, when the electron beam is applied to the coating material, the electron beam spreads over a wide angle through the same material. A natural phenomenon occurs in which a large number of electrons are scattered. On the other hand, the organic polymer of a plastic substrate (mainly acrylic) used as an optical component is exposed to energy such as an electron beam or an ion beam to produce ions or ions. Radicals are generated, and a decomposition reaction occurs due to the chemical activity. When a large number of the above-mentioned scattered electrons come into contact with the substrate, the decomposition reaction of the organic polymer is caused on the surface layer of the substrate, and the decomposition reaction of the electrons also occurs to lower the surface layer to a low molecular weight. In addition, there is a problem that the adhesion of the thin film adhered to the surface layer is reduced.

Therefore, conventionally, there has been a problem that an optical thin film formed on the substrate by electron beam heating vapor deposition is peeled off from the substrate after formation.

Accordingly, the present invention has been made in view of these problems, and even after electron beam heating, the optical thin film formed thereafter does not peel off from the surface of the above-mentioned plastic substrate, thereby improving the adhesion of the thin film. It is an object of the present invention to obtain an optical device manufacturing apparatus.

[Means for solving the problem]

As a result of the research conducted by the present inventors, based on the vacuum evaporation method, the coating material was evaporated by electron beam heating, and a thin film made of the evaporated coating material was formed as an optical thin film on a plastic substrate used as an optical component. Thus, in an apparatus or a method for manufacturing an optical element formed by a plastic substrate and an optical thin film, a plurality of excitation means are arranged in parallel with a space between the coating material and the plastic substrate. Then, the coating material evaporated from the electron beam heating reaches the plastic substrate via the magnetic field, and the optical thin film is formed on the plastic substrate. Reached.

[Operation] As described above, in the present invention, when a coating material is heated by electron beam heating based on a vacuum deposition method to form an optical thin film on a plastic substrate, a plurality of excitations are caused between the coating material and the plastic substrate. Because the magnetic field is provided by the means, the scattered electrons do not reach the plastic substrate. Therefore, since only the evaporated coating material reaches the plastic substrate via the magnetic field, the optical thin film formed on the plastic substrate does not peel off from the substrate.

Next, an embodiment of the present invention will be described with reference to the drawings. However, the “plastic substrate” here is not limited to a simple flat plate, but may be an optical element such as a lens or a prism.

[First Embodiment] FIG. 1 is a schematic configuration diagram showing an apparatus for manufacturing an optical element when the above-described electric field is provided according to a first embodiment of the present invention.

In FIG. 1, in a vacuum chamber 1, a large number of plastic substrates 3 used as optical components are set on a support plate 2 disposed on the upper side thereof. A light source 4 that emits an electron beam is disposed below the vacuum chamber 1, and a light-emitting portion 4 a of the light source 4 is provided with a coating material 5. A metal piece 6 is provided between the substrate 3 and the coating material 5 while keeping the material 5 and the substrate 3 separated. An application unit 7 for applying a high voltage to the metal piece 6 is provided outside the vacuum chamber 1.

With the above configuration, when the electron beam is applied to the coating material 5 from the light source 4 in a state where a high voltage is applied to the metal piece 6 by the application unit 7, more electron beams are spread through the material 5 at a wide angle. Are scattered, while an electric field is generated between the coating material 5 and the metal piece 6 being applied.
In this electric field, the large number of electrons are adsorbed on the metal piece 6 by the above-mentioned attraction action, and the material evaporated from the electron beam is formed on the respective substrates 3 via the periphery of the metal piece 6.

FIG. 2 is a schematic configuration diagram showing an apparatus for manufacturing an optical element when the above-described magnetic field is provided according to a second embodiment of the present invention.

In FIG. 2, the members having the same reference numerals as those in FIG. 1 are the same members, and the description thereof will be omitted. In the figure, a large number of magnets 8 are arranged in parallel in an in-plane A located perpendicular to a straight line 1 from the coating material 5 toward the substrate 3 with an interval such that a repulsive magnetic field is generated. The magnet 8 is supported on the inner peripheral wall of the vacuum chamber 1 via a support member 9.

The large number of magnets 8 as viewed from above in the vacuum chamber 1
3 is shown in FIG. 3 and has a radially extended configuration. The configuration in each direction extending in the radial direction is the same, but a part is shown by a two-dot chain line for simplification. Second
The plane A in the figure is the same as the plane of the paper in FIG. 3, and a magnetic field in which repulsive force acts in the radial direction, the circumferential direction, and the direction of the involute curve located in this plane is generated. A large number of magnets 8 are arranged at intervals, and these magnets 8 are supported on the inner peripheral wall of the vacuum chamber 1 in FIG. The large number of magnets 8
Constitutes an exciting means for generating a repulsive magnetic field.

With the above configuration, when an electron beam is applied to the coating material 5 from the light source 4 shown in FIG. 2, scattered electrons generated in the same manner as described above are generated by the repulsive force of the magnetic field generated in the space between the magnets 8. The light source 4 is moved toward the light source 4, so that contact with the substrate 3 can be prevented. In this state, only the above-mentioned evaporated material is formed on the substrate 3 as an optical thin film via the magnetic field.

Next, a description will be given of respective trial production examples in which an optical element is produced by using the present apparatus shown in FIG. 1 or 2.

[Trial Production Example 1] Using the apparatus shown in FIG. 1, a large number of the plastic substrates 3 were set on a support plate in a vacuum chamber 1, and the inside of the chamber 1 was evacuated to 1 × 10 ⁻⁵ Torr. Thereafter, a high voltage of 500 V is applied to the metal piece 6 by the application means 7,
The coating material 5 of Al ₂ O ₃ , ZrO ₂ , and SiO ₂ was heated and evaporated in order based on electron beam heating deposition. At this time, a large number of electrons are scattered from the electron beam spread at a wide angle via the coating material 5, and
The large number of electrons were adsorbed to the metal piece 6 by the attraction action in the electric field around the metal piece 6. On the other hand, the material evaporated from the electron beam was sequentially deposited on the substrate 3 through the periphery of the metal piece 6, so that a three-layer antireflection film was formed on the substrate 3.

[Trial Production Example 2] Through the same process as from the substrate set in Trial Production Example 1 to the application of a high voltage of 500 V, ZrO ₂ , SiO ₂ ,
The coating material 5 of ZrO ₂ , SiO ₂ , ZrO ₂ , and SiO ₂ was heated and evaporated in order. Also at this time, a large number of electrons are scattered and adsorbed on the metal piece 6 in the same manner as described above, and the evaporated material is sequentially deposited on the substrate 3 through the periphery of the metal piece 5.
A six-layer antireflection film was formed thereon.

[Trial Production Example 3] Using the present apparatus shown in FIG. 2, a large number of the plastic substrates 3 were set, and then Zr was heated by electron beam.
The coating material 5 of O ₂ , SiO ₂ , ZrO ₂ , SiO ₂ , ZrO ₂ , and SiO ₂ was heated and evaporated in this order. At this time, a large number of electrons were scattered in the same manner as described above, but these electrons stopped between the light source 4 and the magnet 8 due to the repulsive force of the magnetic field located between the magnets 8. On the other hand, the material evaporated from the electron beam was sequentially deposited on the substrate 3 via a magnetic field to form a six-layer antireflection film.

[Trial Production Example 4] The substrate 3 was set in the same manner as in Trial Production Example 3, and then MgO, a mixture of ZrO ₂ and TiO ₂ , SiO ₂
Was heated and evaporated in order. Also at this time, a large number of electrons scattered in the same manner as described above survive between the light source 4 and the magnet 8 due to the repulsive force in the magnetic field, and only the evaporated material is sequentially deposited on the substrate 3 via the magnetic field. Deposited. By this vapor deposition, three optical thin films were formed on the substrate 3.

Comparative Example 1 The metal plate 6 in FIG. 1 and the magnet 8 in FIG. 2 were not provided.
Using a conventional apparatus in which nothing is disposed between the coating material 5 and the substrate 3, Al ₂ O ₃ , ZrO ₂ , S
The coating material of iO ₂ was sequentially heated and evaporated, and was sequentially deposited on the substrate 3 to form a three-layer antireflection film on the substrate 3.

The following tests were performed using each of the optical elements of Prototype Examples 1 to 4 and Comparative Example 1 produced as described above. Table 1 shows the results.

[Test Example 1] After a cellophane tape was stuck on the surface of the thin film, it was peeled off thoroughly and the adhesion of the thin film was examined.

[Test Example 2] The film was left to stand in a thermo-hygrostat at 50 ° C.-90% RH for 24 hours, and thereafter, the moisture resistance of the thin film was examined based on the presence or absence of peeling.

[Test Example 3] The thin film was allowed to stand in a thermostat at 70 ° C for 24 hours, and thereafter, the heat resistance of the thin film was examined based on the presence or absence of peeling.

[Test Example 4] A mixture of 80% ether and 20% methyl alcohol was sufficiently impregnated into silbon paper, and the silbon paper was strongly rubbed on the surface of the thin film ten times to examine the scratch resistance of the thin film.

According to Table 1, the prototypes 1 to 4 are comparative examples 1
The adhesiveness of the thin film, the moisture resistance, and the like could be improved as compared with those of the thin film.

[Trial Production Example 5] By using the present apparatus shown in FIG. 1, through the same process as the above-described trial production example 1 from the substrate setting to the application of a high voltage of 500 V,
The coating material 5 of ZrO ₂ was heated and evaporated by electron beam heating.
At this time, similarly to the above, a large number of electrons are scattered from the electron beam passing through the coating material 5, are adsorbed by the metal piece 6 being applied, and the evaporated material is passed through an electric field around the metal piece 6. Evaporation was performed on the substrate 3, whereby a single-layer antireflection film was formed on the substrate 3.

[Trial Production Example 6] Using the present apparatus shown in FIG. 2, the substrate 3 was set in the same manner as in Trial Production Example 3, and then ZrO _{2 was} heated by electron beam heating.
Was heated and evaporated. Also at this time, a large number of electrons are scattered in the same manner as described above, and survive between the light source 4 and the magnet 8 by the repulsive force in the magnetic field, and the material evaporated from the electron beam passes through the magnetic field to the substrate 3. A single-layer antireflection film was formed on the substrate 3 in the same manner as in Prototype Example 5.

[Comparative Example 2] Similar to Comparative Example 1, the metal plate 6 in FIG. 1 and the magnet 8 in FIG. 2 are not provided, and nothing is disposed between the coating material 5 and the substrate 3. The coating material 5 of ZrO ₂ is heated and evaporated by electron beam heating using the apparatus described above.
A single-layer antireflection film was formed on the substrate 3 by vapor deposition.

In Prototype Examples 5, 6 and Comparative Example 2 as well as Prototype Example 3 described above, the amount of electrons near the substrate 3 was measured using a Faraday cup during heating and evaporation of the coating material 5 by an electron beam. Table 2 shows the results.

According to Table 2, the prototypes 3, 5, and 6 are compared with the comparative example 2.
It was proved that the amount of electrons in the vicinity of the substrate 3 was smaller than that of the substrate 3.

In addition, tests were performed in the same manner as in Test Examples 1 to 3 using the optical elements of Prototype Examples 5 and 6 and Comparative Example 2. Table 3 shows the results.

In Table 3, similarly to Table 1 described above, the prototypes 5 and 6 were able to improve the adhesiveness and moisture resistance of the thin film as compared with Comparative Example 2.

According to the above-described embodiment, the metal piece 3 in FIG. 1 is positioned parallel to the substrate 3, but is not limited thereto, and may be in a direction (vertical direction in the figure) orthogonal to one surface of the substrate 3. The substrate 3 may be erected along the surface, and the scattered electrons are adsorbed on the metal piece 3 by the electric field generated around the substrate 3, so that the same effect as described above can be obtained. .

Further, the large number of magnets 8 shown in FIG.
Although they are arranged side by side in the radial direction and the circumferential direction, they may be juxtaposed in a matrix in an in-plane A in FIG. 2 with an interval enough to generate the magnetic field. Instead of a large number of magnets 8, an electromagnetic coil may be provided in parallel, and an exciting unit for generating a repulsive magnetic field via the coil may be provided, for example, outside the chamber 1 in FIG. The effect can be obtained in the same manner as described above.

Furthermore, in this embodiment, since only electron beam heating evaporation is performed, mass productivity of optical elements can be improved.

[Effects of the Invention] According to the above invention, when a coating material is heated by electron beam heating based on a vacuum evaporation method to form an optical thin film on a plastic substrate, a gap is provided between the coating material and the plastic substrate. Since a plurality of magnets are arranged, a magnetic field is formed between the coating material and the plastic substrate, so that scattered electrons can be prevented from reaching the plastic substrate.

Therefore, only the evaporated coating material is vapor-deposited on the substrate, and the optical thin film formed on the substrate afterward is not separated from the substrate, so that the adhesion can be improved.

Further, since the film can be formed on the substrate by electron beam heating evaporation, the coating material is not limited, and an optical element having desired optical characteristics such as an antireflection film and a reflection film can be manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an apparatus for manufacturing an optical element according to a first embodiment of the present invention. FIG. 2 is a schematic configuration diagram showing an optical element manufacturing apparatus according to a second embodiment of the present invention. FIG. 3 is a schematic top view showing a number of magnets 8 in FIG. [Description of Signs of Main Parts] 3 ... Plastic substrate, 4 ... Light source 5 ... Coating material, 6 ... Metal piece 7 ... Applying means, 8 ... Magnet

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G02B 1/00-1/12 G02B 5/20-5/28 C23C 14/00-14/58

Claims (2)

(57) [Claims] 1. A coating material is evaporated by electron beam heating based on a vacuum evaporation method, and a thin film made of the evaporated coating material is formed on a plastic substrate used as an optical component.
In an apparatus for manufacturing an optical element formed as an optical thin film and formed by the plastic substrate and the optical thin film, a plurality of excitations are arranged in parallel with a distance between the coating material and the plastic substrate to form a magnetic field. Means for forming the optical thin film on the plastic substrate by providing a means and allowing the coating material evaporated by the electron beam heating to reach the plastic substrate via the magnetic field. 2. A coating material is evaporated by electron beam heating based on a vacuum deposition method, and a thin film made of the evaporated coating material is formed on a plastic substrate used as an optical component.
In the method for producing an optical element formed as an optical thin film and formed by the plastic substrate and the optical thin film, a plurality of exciting means are arranged in parallel with an interval between the coating material and the plastic substrate, and The method of manufacturing an optical element, wherein the coating material evaporated by the beam heating reaches the plastic substrate via the magnetic field, thereby forming the optical thin film on the plastic substrate.