JPH06186407A - Reflective body - Google Patents

Abstract

PURPOSE:To obtain a reflective body having a reflective film having high reflectance and being superior in corrosion resistance by forming an alloy layered reflective film incorporating Pt group metals consisting essentially of silver on a base plate. CONSTITUTION:The alloy reflective film 2 incorporating the Pt group metal consisting essentially of Ag is formed on the base plate 1. As the base plate 1, glass, metal and a resin base plate, etc., are used. Also the base plate formed an organic film substrate after a pretreatment aimed the flatness was carried out on the base plate 1 may be used. The reflective film 2 consists of an alloy incorporating >=70wt.% Ag and the alloy consists of combinations of e.g. Ag and Pd, Ag and Pt, Ag, Pd and Pt. In this case, the Pd content is preferably 1-30wt.% and the Pt content is >=1-30wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a reflector such as a plane mirror or a curved mirror used in an optical instrument including a laser instrument, a vehicle lighting device such as a headlight or a foglight, and an indoor / outdoor illumination device. Regarding reflectors.

[0002]

2. Description of the Related Art A reflector in which an aluminum film is formed by a vacuum vapor deposition method to form a reflective film is known. Further, there is a reflector in which a silver film is formed as a reflective film by a vacuum evaporation method in order to improve the reflectance. However, since this reflector directly exposes the metal film to the outside air, the surface of the reflection film is corroded.

As a solution to this problem, a reflector having a transparent film such as a silicon oxide film, an aluminum oxide film, a titanium oxide film, or a magnesium fluoride film formed on the surface of the reflective film by a vacuum deposition method to serve as a corrosion protection film, or the reflective film. There is a reflector whose surface is coated with an organic paint to form a protective film. In addition, Japanese Examined Japanese Patent Sho 62-4
2994 discloses that an aluminum-zirconium alloy reflective film is formed to prevent corrosion.

[0004]

In recent years, there has been an increasing demand for lighting equipment with high illuminance at low power cost, so that a reflector having a reflective film having a higher reflectance than the conventional reflective film is required. ing. Aluminum is used for most of the reflection films of conventional products, but the maximum reflectance of aluminum is 9
It is about 2%, and further increase in reflectance cannot be expected.

Silver has a high reflectance, but when exposed to the atmosphere, silver turns black due to sulfurization or becomes cloudy due to chloride. In order to prevent the corrosion of the silver film, there is a reflector that has a transparent protective film of oxide or fluoride formed by a vacuum deposition method, but silver has a very weak adhesion with the protective film compared to aluminum, so it is easy to peel off. The interface between the protective film and the silver film, which have poor adhesion, becomes electrochemically unstable and becomes a factor that promotes silver corrosion. The reflector coated with organic paint is
It overcomes the corrosion of silver, but it is labor intensive to handle organic paints and has environmental hygiene problems. Also, this reflector is
Since the irregularities on the reflective film surface are conspicuous, the appearance of the product is poor. The aluminum-zirconium alloy reflective film reported in Japanese Patent Publication No. 62-42994 has superior corrosion resistance to the aluminum reflective film, but has a lower reflectance than the aluminum reflective film.

Therefore, an object of the present invention is to provide a reflector having a reflective film having a high reflectance and an excellent corrosion resistance.

[0007]

In order to solve the above-mentioned problems, the reflector according to the present invention comprises an alloy layer reflective film containing a platinum group metal containing silver as a main component on a substrate. Examples of the substrate include glass, metal and resin substrates. Further, a substrate in which an organic film underlayer is formed by subjecting these substrates to pretreatment for the purpose of smoothness may be used.

The reflective film of the present invention is not particularly limited, but is preferably made of an alloy containing 70% by weight or more of silver. The alloy forming the reflective film is made of, for example, a combination of silver and palladium, silver and platinum, silver and palladium and platinum, but not limited to the following, except for accidental impurities. Increasing the palladium content of the silver-palladium alloy reflective film improves the corrosion resistance, but tends to reduce the reflectance, so the palladium content is preferably 1 to 30% by weight. Increasing the platinum content of the silver-platinum alloy reflection film improves the corrosion resistance in the same manner as described above, but decreases the reflectance although not as much as palladium. Further, since platinum is expensive, the platinum content is preferably 1 to 30% in consideration of reflectance, corrosion resistance and cost. For the same reason, the total content of palladium and platinum in the silver-palladium-platinum alloy reflection film is preferably 1 to 30% by weight.

[0009]

Function Pure silver has high reflectance but poor corrosion resistance. On the other hand, platinum group metals such as palladium and platinum have excellent corrosion resistance. The reflector of the present invention has a high reflectance and excellent corrosion resistance because it has an alloy reflection film formed of a combination of silver and palladium, silver and platinum, and a combination of silver, palladium and platinum.

[0010]

1 and 2 schematically show an embodiment of a reflector according to the present invention. In the embodiment shown in FIG. 1, the alloy reflection film 2 is formed on the substrate 1. In the embodiment of FIG. 2, the organic base film 3 is formed on the substrate 1 as a pretreatment, and the alloy reflection film 2 is formed thereon. The method of making this reflector will be described below.

Silver (pure 99.9%) and palladium (purity 99.9%) were put into a boron nitride crucible and heated at 1500 ° C. in an argon atmosphere (1 atm) to prepare a silver-palladium alloy. did. By the same method, silver and platinum were heated at 1800 ° C. to prepare a silver-platinum alloy. At this time, since the evaporation rates of the individual metals were different, the addition amounts of palladium and platinum were determined in consideration of the evaporation rates of the individual metals. The substrate used was one in which an epoxy-based organic film was applied to the aluminum surface. The electron beam evaporation method was used for the vapor deposition of the alloys. The deposition rate of each alloy was 3 nm / sec and the film thickness was 0.2.
A film was formed with a thickness of μm to obtain a reflector. Also, a comparative reflector was obtained using only platinum.

As the evaluation of the obtained reflector, composition ratio analysis of the film by X-ray microanalyzer (XMA), reflectance measurement after film formation (wavelength range 400 to 800 nm), corrosion test by salt spray, after corrosion test Of reflectance (wavelength range 40
0-800 nm). The salt spray corrosion resistance test was conducted for 48 hours, and the evaluation was judged by the appearance of the film. A: The film has a good appearance without discoloration or peeling due to corrosion.

B: There is no peeling of the film, but a slight discoloration occurs. C: Discoloration and peeling of the film due to corrosion are observed. Table 1 shows the evaluation results of the reflector formed with the silver-palladium alloy reflection film, and Table 2 shows the evaluation results of the reflector formed with the silver-platinum alloy reflection film.

[0014]

[Table 1]

[0015]

[Table 2]

As shown in Tables 1 and 2, the reflector formed with a pure silver reflection film shows a very high reflectance before the salt spray test, but after the salt spray test, it becomes cloudy due to chlorination. And peeling of the film were observed, and it can be seen that silver alone does not exhibit satisfactory behavior as a reflective film. On the other hand, when palladium or platinum is contained in silver, cloudiness and film exfoliation due to salt spray do not occur, and when the platinum group metal is contained in silver, it can be said that the corrosion resistance of the reflective film is improved. However, since the reflectance of the film decreases as the content of the platinum group metal increases, it is not preferable to contain 30% by weight or more of the platinum group metal.

[0017]

EFFECTS OF THE INVENTION The reflector of the present invention is formed with a reflection film having a higher reflectance than that of an aluminum film and excellent in corrosion resistance. Therefore, compared with a lighting device or an optical device using a conventional reflector, Power consumption can be reduced. Also,
Since it is not necessary to form a protective film on the surface of the silver film, the process and cost can be reduced and the appearance as a reflector is beautiful.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a reflector of the present invention.

FIG. 2 is a sectional view showing a structure of a reflector of the present invention.

[Explanation of symbols]

 1 substrate 2 alloy reflective film 3 organic base film formed by applying organic paint

Claims (6)

[Claims] 1. A reflector comprising a substrate and an alloy layer reflective film containing a platinum group metal containing silver as a main component. 2. The reflector according to claim 1, wherein the substrate is subjected to a pretreatment for the purpose of improving the adhesion between the substrate and the reflective film and smoothing the reflector. 3. The reflector according to claim 2, wherein an organic film is formed as a pretreatment. 4. The reflection film is formed of an alloy layer containing silver and palladium, and the content of silver in the alloy is 70% by weight or more and the content of palladium is 30% by weight or less. The reflector according to any one of 1. 5. The reflection film is formed of an alloy layer containing silver and platinum, and the content of silver in the alloy is 70% by weight or more and the content of platinum is 30% by weight or less. The reflector according to any one of 1. 6. The reflection film is formed of an alloy layer containing silver, palladium and platinum, and the content of silver in the alloy is 70% by weight or more, and the content of palladium and platinum in total is 30% by weight or less. The reflector according to any one of claims 1 to 3.