JPH1046322A - Production of multilayer reflecting film by laser vapor deposition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a multilayer reflecting film excellent in adhesive strength, heat resistance and durability by forming a polymer backing film and an aluminum reflecting film on a substrate and then forming a hardened material protecting film with polysiloxane while introducing oxygen radical. SOLUTION: A polymer backing film of PP, etc., is formed on a flat, spherical or semispherical substrate by laser vapor deposition. Aluminum is then vapor-deposited to form a reflecting film. Subsequently, a polymer hardened material protective film is formed from polysiloxane by laser vapor deposition while introducing oxygen radical. In this method, a hard higher-mol.wt. polymer of dense structure is formed from polysiloxane by laser vapor deposition in the presence of oxygen radical, and further a film consisting essentially of silicon oxide having a physical property as an inorg. matter is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a reflection film by a laser deposition method.

[0002]

2. Description of the Related Art Conventionally, it has been considered that it is effective to use aluminum (Al) as a reflection film for reflecting light such as laser light, and multilayer reflection films having various film constitutions have been studied. ing. This aluminum (A
As a reflective film using l), for example, as a practical technique, an acrylic resin is coated on a plastic substrate, cured by ultraviolet (UV) irradiation, and further treated with hot air to form a polymer base film. A proposal has been made in which an aluminum reflective film is formed thereon by a vapor deposition method, and finally, a protective film is provided by coating a transparent acrylic resin as a surface layer. It is known that a resin called plastic can be used as a substrate for the reflective film, and that the manufacturing process is relatively simple.

[0003] However, there is a major problem in the structure of this conventional reflection film and its manufacturing method. First, when a base film is formed on a plastic substrate by resin coating, the degree of adhesion between the substrate surface and the coating film is not very high because the substrate surface is not smooth. There is a problem that interface deterioration due to heat accompanying light reflection at the time of use is liable to occur and peeling is easy. A similar problem is unavoidable even between the underlayer and the aluminum (Al) reflection film.

Second, a transparent resin film as a protective film disposed on the aluminum reflective film has a problem not only in adhesion strength with the aluminum reflective film but also in a resin film. There has been a serious problem in abrasion resistance and heat resistance, and further, it has been a serious problem that deterioration due to heat during use of the reflection film is inevitable. To solve the above problems, for example, it is conceivable to replace the film formation of a resin film with a vapor deposition method instead of the coating method. However, the film formation efficiency, the uniformity of the film formation, and the denseness of the film formation structure are considered. Practically, there are many difficulties in terms of properties, substrate adhesion, and the like, and the surface protective film also has difficulties in terms of heat resistance, weather resistance, durability, and the like as being a resin film.

Therefore, the present invention solves the above-mentioned problems of the prior art, and is excellent in adhesion strength, heat resistance, durability and the like as a reflection film for laser light and the like, and has good productivity.
It is an object of the present invention to provide a new method for manufacturing an aluminum multilayer reflective film.

[0006]

According to the present invention, a polymer film is formed on a surface of a substrate by laser deposition to form a base film, and then an aluminum reflective film is formed. A method for producing a multilayer reflective film by a laser vapor deposition method, comprising forming a cured product protective film by laser vapor deposition using polysiloxane as a raw material under the introduction of oxygen radicals after vapor deposition.

Further, the present invention relates to a method of forming a flattened film structure by forming a polymer film on a rough resin substrate by laser vapor deposition in connection with the above manufacturing method, Also provided is a method for forming a planarized film structure, which comprises forming a polymer film having a reflow property and gradually forming a polymer film having a higher film hardness.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is essentially characterized by forming a polymer film as a base film and forming a cured product protective film as a surface protective film by laser vapor deposition as described above. FIG. 1 shows the steps of the present invention. The laser vapor deposition process shown in FIG. 1 is performed by a technique such as acrylic resin coating in a conventional example.

That is, as shown in FIG. 1, a resin substrate as an underlayer, for example, from various types of resins such as polycarbonate, polyacrylate, polyolefin, polysulfone, polyester, polyamide, and polyimide, and furthermore, A polymer base film is formed by laser deposition on a flat, spherical, or aspherical substrate selected from a composite material or the like according to the purpose and application.

In this case, as the polymer base film, various kinds of materials such as polyolefin such as polypropylene, poly (meth) acrylate, and polysiloxane are used as raw materials for laser vapor deposition. After forming the base film by laser evaporation, aluminum is evaporated to form a reflective film.

Subsequently, a polymer cured product protective film is formed by laser vapor deposition using polysiloxane as a raw material.
Regarding the formation of the base film in the above steps, it is very difficult to realize a flat hard base film on a rough resin substrate with a single film. It is also effective to use the same apparatus to form a tilt function. That is, for example, a polymer film having a different composition is formed on a non-spherical resin substrate (having large irregularities) having a surface roughness stepwise to form a polymer film having a reflow property at first. Then, the hardness of the film is gradually increased to form an optically smoothed base film of the functionally graded polymer film. Annealing after film formation is also effective.

In the present invention, it is recommended that the underlying film be formed by laser vapor deposition of polysiloxane as one of more specific embodiments. In the case of this polysiloxane, a film having reflow properties is first formed by laser vapor deposition, and then a hard film is deposited by laser vapor deposition while introducing oxygen radicals. As a result, a functionally graded base film is formed.

Of course, various other embodiments are possible. Also, the formation of a cured product film as a protective film is one of the major features of the method of the present invention. In this method, a polysiloxane as a target is hardened by laser evaporation in the presence of oxygen radicals. An important finding by the inventor of the present invention that it is possible to produce a high-molecular-weight polymer with a dense structure and to produce a film mainly composed of silicon oxide having physical properties as an inorganic substance. Based on

There are no particular restrictions on the thickness of the base film, the aluminum reflection film, and the cured product protective film. Usually, each of them can be formed as a thicker film in the range of several hundreds to several thousand degrees if necessary. Hereinafter, examples will be shown, and embodiments of the present invention will be described in more detail.

[0015]

【Example】

(Example 1) Laser deposition was performed on a heat-resistant polycarbonate resin substrate having an aspherical curved surface using polysiloxane. As the film forming conditions, the substrate temperature was set to room temperature, the polysiloxane raw material was heated and evaporated at a laser output of 5 to 10 W, and vapor deposition was performed under vacuum.

Since the polysiloxane raw material has a relatively low evaporation temperature, it has a higher deposition rate (20%) than other resin raw materials.
0 to 300 nm / min). The obtained film had good adhesion to substrate and weather resistance and moisture resistance,
When the film was subjected to a heat treatment, the film softened at almost the same temperature as the raw material, and did not have heat resistance. Also, when polysiloxane is actually applied to the formation of a base film for a reflector,
It was also confirmed that if the surface of the underlying substrate was not flat, the film formed by laser deposition alone would largely reflect the irregularities of the underlying substrate, making it difficult to planarize the surface. Then, a heat treatment (softening temperature) was performed after the laser deposition to soften the film. This utilizes the fact that reflowability is very good. This is shown using a substrate simulating irregularities as the base substrate, and the polysiloxane laser shown in FIG.
4 is a cross-sectional photograph of the film after the vapor deposition (before heat treatment), and is a cross-sectional photograph of the film after heat treatment in FIG. 3. It can be seen that the reflow property is good. Therefore, a film having good reflow properties is actually formed on a substrate whose surface is not flat, that is, a substrate having a rough surface, and is subjected to a heat treatment to cause a downflow to form a smooth film.

Next, on the film after the heat treatment, laser radical evaporation of polysiloxane was performed by introducing oxygen radicals to form a flat and hard film. At this time, laser vapor deposition by introducing oxygen radicals can be performed by the apparatus and method described in Example 3 described later. By this vapor deposition, a hard film having a high molecular weight was obtained, and there was no change even when the film was heated to 400 ° C. or higher, and a base film having hardness, heat resistance, and excellent surface flatness was obtained.

As described above, by controlling the injection amount of oxygen radicals at the time of laser deposition of polysiloxane, a film is formed with a gradient function, and a flat base film is formed on a rough substrate having irregularities. be able to. Next, an aluminum (Al) film as a reflection film was formed on the obtained base film by a known vacuum evaporation method. This aluminum reflective film may be formed by sharing the apparatus main body in laser vapor deposition and evaporating aluminum by heating resistance or the like instead of laser irradiation. (Example 2) Polypropylene was laser-deposited in place of laser deposition of polysiloxane in Example 1.

In this case, the deposition rate is 10 nm / min.
The film formation was as follows. Heat treatment after film formation and laser vapor deposition by oxygen radical introduction were not performed. Although not sufficient in terms of heat resistance and film strength, a base film having good adhesion to a substrate and surface flatness was obtained. Similarly,
An aluminum reflection film was formed on the polypropylene vapor-deposited film. (Example 3) On the aluminum film of the multilayer reflective film obtained in Example 1, polysiloxane was laser-deposited to form an oxide protective film.

FIG. 4 illustrates the configuration of a film forming apparatus for that purpose. Polysiloxane was disposed on a target in the chamber, and the multilayer film as a substrate was disposed above the polysiloxane. Polysiloxane has a softening temperature of 80-9
Using a resinous material at 0 ° C., a film was formed under the same vapor deposition conditions.

Microwaves and oxygen are supplied to a quartz tube inserted from the side of the chamber shown in FIG. 4, oxygen plasma is generated in the quartz tube, oxygen radicals are introduced on the surface of the substrate, and the substrate is illuminated with a lamp. The cw-CO ₂ laser beam was mirrored from the top of the chamber and Zn
Irradiation was performed on the target surface through the Se window to form a film.

FIG. 5 shows a laser output of 10 W and an oxygen pressure of 50.
FIG. 6 shows the dependence of the deposition rate on the substrate temperature when the film was formed by changing the substrate temperature under a constant mTorr and a microwave power of 100 W. FIG. 6 shows the dependence of the element component ratio of the produced film on the substrate temperature. Are respectively shown. FIG. 5 shows that the deposition rate decreased with increasing substrate temperature, and FIG.
It can be seen that the carbon component (C) of the resulting film decreases as the substrate temperature increases. Further, as a result of measuring the molecular weight of the film, when laser deposition is performed with the substrate temperature set close to the softening temperature of the raw material, the resulting film has a molecular weight that is 20 times or more higher than the molecular weight of the raw material of about 2100. Had become a membrane.

From these results, it can be seen that the film formed by laser deposition can be changed from a soft polysiloxane film having reflow properties to a hard polysiloxane polymer film by controlling the substrate temperature and the oxygen radical injection amount. Further, it can be seen that a silicon oxide film having less carbon component can be transferred, and when used as a protective film for a reflector, it is sufficient if the substrate temperature is higher than the softening point of the raw material.

The laser-deposited film of polysiloxane has good adhesion to the underlying substrate, and when an oxygen radical is introduced into an oxide film, not only the adhesion but also the film strength is greatly improved. The same was true when the underlying substrate was replaced with Al. Moreover, the hard protective film obtained by oxygen radical injection is invariant even in a temperature environment of 400 ° C. or higher,
It has sufficient heat resistance and is practically satisfactory. Further, as illustrated in FIG. 7, the optical transmission characteristics of the protective film exhibited a high transmittance exceeding 90% (visible light region).

[0025]

As explained in detail above, the laser deposition method of the present invention into which oxygen radicals have been introduced allows the adhesiveness,
It is possible to produce a reflective mirror protective film with excellent properties such as heat resistance, and it is very effective and practical as a new reflective film manufacturing method combining the formation of a flat underlayer with a functionally graded polymer multilayer film. An excellent method is provided.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating a process chart of a method for manufacturing a reflection film according to the present invention.

FIG. 2 is a photomicrograph in place of a drawing illustrating a state after laser deposition and before heat treatment when forming a base film.

FIG. 3 is a photomicrograph instead of a drawing illustrating a state after a heat treatment following the state of FIG. 2;

FIG. 4 is a diagram illustrating a schematic view of a film forming apparatus in the manufacturing method of the present invention.

FIG. 5 is a relationship diagram illustrating the substrate temperature dependence of the deposition rate.

FIG. 6 is a relationship diagram illustrating the substrate temperature dependence of the C / Si ratio.

FIG. 7 is a relationship diagram illustrating the optical transmission characteristics of a cured product protective film on the outermost surface.

Claims (8)

[Claims] 1. A polymer film is formed on a surface of a substrate by laser vapor deposition to form a base film, then an aluminum reflective film is vapor-deposited, and then laser vapor-deposited using polysiloxane as a raw material under the introduction of oxygen radicals. A method for producing a multilayer reflective film by a laser vapor deposition method, comprising forming a cured product protective film. 2. The method according to claim 1, wherein the underlayer is formed by laser deposition as a multilayer film. 3. The method according to claim 2, wherein a polymer film having a reflow property is formed, and a polymer film having a higher film height is gradually formed. 4. The method according to claim 1, wherein a heat treatment is performed after the laser deposition to form a base film. 5. The method according to claim 1, wherein the base film is formed by laser vapor deposition using at least one of polyolefin, polysiloxane and poly (meth) acrylate as a raw material. 6. The method according to claim 1, wherein the substrate is an aspheric resin substrate. 7. A method for forming a planarized film structure by forming a polymer film on a roughened resin substrate by laser vapor deposition, wherein a polymer film having reflow properties is formed, and the film hardness is gradually increased. A method for forming a planarized film structure, characterized by forming a polymer film having a high level. 8. The method according to claim 7, wherein a heat treatment is performed after the laser deposition.