JP2009021020A - Lighting fixture for vehicle having reflector excellent in corrosion resistance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting fixture for a vehicle having a reflector excellent in corrosion resistance with an aluminum-alloy reflecting film formed on the surface of a base member or on the surface of an undercoat formed on the base member. <P>SOLUTION: The aluminum-alloy reflecting film 6 formed on the reflector 1 of the lighting fixture for the vehicle comprises an aluminum alloy containing Mg of 0.3 to 10 mass% and Ce of 2 to 10 mass%, with the rest of Al or inevitable impurities. Its uppermost surface is constituted of a barrier film 8 of an oxide containing Al and Mg, and substantially containing no Ce. No protective film is formed on the aluminum-alloy reflecting film 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicular lamp having a reflector excellent in corrosion resistance (for example, an automotive headlamp, a marker lamp, etc.).

Conventionally, the functional part of a vehicular lamp (for example, an automobile headlamp, a marker lamp, etc.) has a basic structure including a reflector 1, a light source 2, and a lens 3, as shown in the sectional view of FIG. Yes. As shown in the sectional view of FIG. 2, the reflector 1 in the conventional vehicular lamp includes a base material 4 and an undercoat 5 formed on the base material 4 (the undercoat 5 may not be provided). And a reflective film 6 made of aluminum or an aluminum alloy formed on the undercoat 5 and a protective film 7 for protecting the reflective film 6 formed on the reflective film 6 from corrosion. Is formed.
The substrate 4 is generally made of BMC (bulk molding compound), PEI (polyetherimide), PES (polyethersulfone), PPS (polyphenylene sulfide), PPT / PET (polypropylene terephthalate / polyethylene terephthalate), PBT (polybutylene It is known to be made of a synthetic resin such as terephthalate), PC (polycarbonate), ABS (acrylonitrile / butadiene / styrene resin), AAS (acrylonitrile / acrylic acid ester / styrene resin).
It is also known that the undercoat 5 is made of a thermosetting acrylic resin-based paint, a UV-curable acrylic resin-based paint, an organic siloxane plasma CVD film, or the like.
Further, the reflective film 6 is pure Al of purity 99.85% by mass or more such as JIS1050, JIS1070, JIS1080, JIS1085, or Fe: 0.05 to 0.15% by mass, Cu: 0.06 to 0.15% by mass. %, Ti: 0.004 to 0.04 mass%, Si, Mg and Mn as impurities are each 0.08 mass% or less, and the balance is composed of an aluminum alloy having a component composition consisting of Al and inevitable impurities Has been. Furthermore, it is known to use a plasma CVD film of organosiloxane as the protective film.
In order to produce the reflector 1, first, a base material 4 is produced by molding a resin raw material by an injection molding method or the like, and the surface of the base material 4 is coated and then thermally cured or UV cured, or plasma CVD. An undercoat 5 is formed by a method, a reflective film 6 made of aluminum or an aluminum alloy is formed on the undercoat 5 by vapor deposition or sputtering, and a protective film 7 is formed by plasma CVD. It is also known to do (see Patent Document 1).
JP-A-6-76609

  In recent years, further cost reduction and performance improvement have been demanded for vehicle lamps. In response to such a demand, as shown in FIG. 1, the formation of a protective film in the reflector 1 is omitted to reduce costs, and further, the performance of the reflector is further improved by eliminating the protective film that absorbs light. Attempts have been made. However, in general, pure Al or an Al alloy is an amphoteric metal and is very weak against acids and alkalis. Therefore, when a conventional aluminum or aluminum alloy film is used as a reflective film and a protective film is not formed, there is a problem that the reflectance decreases in a short period of time.

The present inventors have studied to solve these problems associated with the reflective film made of aluminum or aluminum alloy in the conventional reflector. as a result,
(Ii) Purity: 99.9% by mass or more of Mg: 0.3 to 10% by mass is added to high purity Al having a purity of 99.99% by mass or more, and further purity: 99.9% by mass or more of Ce: 2 -10% by mass, melted, cast, hot worked and machined to obtain Mg: 0.3-10% by mass, Ce: 2-10% by mass, the balance being Al And an Al-Mg-Ce-based Al alloy target having a composition composed of inevitable impurities, and an aluminum alloy reflective film obtained by sputtering using this target, as shown in FIG. A barrier film 8 is formed on the outermost surface, thereby improving the corrosion resistance against acid and alkali. The aluminum alloy reflective film 6 having the barrier film 8 on the outermost surface is used as the reflective film in the reflector 1. When, never long period reflectance is lowered,
(B) The barrier film 8 formed on the outermost surface of the aluminum alloy reflective film 6 does not substantially contain Ce and is composed of an oxide containing Al and Mg. It was obtained.

The present invention has been made based on such research results,
(1) A vehicle lamp having a reflector in which an aluminum alloy reflective film is formed on the surface of a base material or an undercoat formed on the base material,
The aluminum alloy reflective film contains Mg: 0.3 to 10% by mass, Ce: 2 to 10% by mass, the balance is made of an aluminum alloy having a composition consisting of Al and inevitable impurities, and the outermost surface is made of Al and The present invention is characterized by a vehicular lamp having a reflector excellent in corrosion resistance, which is made of a barrier film made of an oxide containing Mg and substantially free of Ce.

The aluminum alloy reflective film is excellent in corrosion resistance because its outermost surface is composed of an oxide film containing Al and Mg and substantially free of Ce. The outermost surface of the aluminum alloy reflective film Even if a protective film is not formed on the surface, the reflectance does not deteriorate for a long time, and when this aluminum alloy reflective film is used, a vehicle lamp equipped with a reflector having a protective film-less reflector can be produced. . Therefore, the present invention
(2) The outermost surface of the aluminum alloy reflective film in the reflector is exposed to the outside, and the protective film is not formed on the outermost surface of the aluminum alloy reflective film. It is characterized by the vehicular lamp.

As shown in FIG. 1, the reflector provided in the vehicle lamp of the present invention has an aluminum alloy reflective film 6 directly on the surface of the base material 1 or on the surface of the undercoat 5 formed on the base material 1. It is produced by forming. This aluminum alloy reflective film 6 contains Mg: 0.3 to 10% by mass, Ce: 2 to 10% by mass, the balance is made of an aluminum alloy having a composition consisting of Al and inevitable impurities, and the outermost surface is made of Al. And a barrier film made of an oxide containing Mg and substantially free of Ce.
The aluminum alloy reflective film can be formed by sputtering, and the sputtering target used at this time is made of high purity Al having a purity of 99.99% by mass or more as a raw material and both having a purity of 99.9% by mass or more. Prepare Mg and Ce. First, melt high-purity Al in a high-vacuum or inert gas atmosphere to produce a high-purity Al melt with as few impurities as possible. Add Mg to the resulting high-purity Al melt. It is added so as to have a predetermined content, further Ce is added, and then ingots are produced by casting in a vacuum or an inert gas atmosphere, and these ingots are hot-worked and then machined. be able to.
In order to form an aluminum alloy reflective film using the sputtering target thus produced, the sputtering target is attached to a DC magnetron sputtering apparatus, the inside of the DC magnetron sputtering apparatus is evacuated by a vacuum evacuation apparatus, and then an inert gas. Then, DC sputtering power is applied to the target by a DC power source to generate plasma between the substrate and the target, and then the resin substrate is heated in the atmosphere for a short time at a temperature at which the resin substrate does not deform. It is formed by heat treatment. A barrier film made of an oxide containing Al and Mg and substantially free of Ce is formed on the outermost surface of the aluminum alloy reflective film thus formed.

  Next, the reason why the component composition of the aluminum alloy reflective film constituting the reflector of the vehicle lamp of the present invention is limited as described above will be described.

Mg:
Mg component dissolves in Al and forms a 1.5 to 3.5 nm thick transparent transparent film on the surface of the aluminum alloy reflective film, thereby maintaining corrosion resistance against alkali while maintaining high reflectivity. Although it is a component which improves the property and suppresses pitting corrosion, even if it contains less than 0.3% by mass of Mg, the desired effect cannot be obtained. This is not preferable because the reflectance decreases. Therefore, the content of the Mg component contained in the aluminum alloy reflective film constituting the reflector of the vehicle lamp of the present invention is set to 0.3 to 10% by mass (more preferably 0.5 to 5% by mass).

Ce:
Ce is added because it has the effect of further improving the corrosion resistance of the aluminum alloy reflective film in a hot and humid environment and further smoothing the surface of the aluminum alloy reflective film obtained by sputtering. Even if the content is less than 10% by mass, the desired effect cannot be obtained. On the other hand, when the content exceeds 10% by mass, pitting corrosion occurs, which is not preferable. Therefore, the Ce content is set to 2 to 10% by mass (more preferably 3 to 7% by mass).

Since the aluminum alloy reflective film constituting the reflector provided in the vehicle lamp of the present invention is excellent in corrosion resistance, even if it is exposed to the atmosphere for a long time as compared with the conventional vehicle lamp, The reflector has a low reflectivity reduction and can be used over a long period of time. Further, it is possible to reduce the cost of the reflector by eliminating the need to form a protective film covering the aluminum alloy reflective film so that a reflector without a protective film can be obtained. Therefore, the cost of the vehicular lamp can be reduced.
The present invention is characterized in that it is a vehicular lamp having a reflector that does not form a protective film on the surface of the aluminum alloy reflective film constituting the reflector, but the present invention forms a protective film on the surface of the aluminum alloy reflective film. It also includes a vehicular lamp having a reflector.

High purity Al having a purity of 99.99% by mass or more was prepared as a raw material, and both Mg and Ce having a purity of 99.9% by mass or more were prepared.
First, the purity prepared in advance: 99.99 mass% or more of high purity Al was melted in vacuum in a high-frequency vacuum melting furnace, and then filled with Ar gas until the pressure in the furnace reached atmospheric pressure. Mg and Ce were added to the molten Al, and then cast into a graphite mold to produce an ingot. The obtained ingot was heated at 430 ° C. for 2 hours, then hot-rolled and machined to have a diameter of 125 mm, a thickness of 5 mm, and a target A having the component composition shown in Table 1. O was produced.

Each of the targets A to O shown in Table 1 is soldered to a backing plate made of oxygen-free copper, and this is mounted on a DC magnetron sputtering apparatus, and the inside of the DC magnetron sputtering apparatus is 1 × 10 ⁻⁴ Pa by a vacuum exhaust apparatus. Then, Ar gas is introduced to obtain a sputtering gas pressure of 1.0 Pa, and then a DC sputtering power of 1000 W is applied to the target by a DC power source, and the target is opposed to the target with a spacing of 70 mm. The plasma was generated between a PC substrate having a length of 110 mm, a width of 60 mm, and a thickness of 3 mm arranged in parallel with the target and the target, and then subjected to heat treatment at 80 ° C. for 10 minutes in the atmosphere. 2 having a component composition shown in FIG. 2, having a barrier layer on the outermost surface, and an overall thickness of 100 nm Certain aluminum alloy reflective films of the present invention (hereinafter referred to as reflective films of the present invention) 1 to 10, comparative aluminum alloy reflective films (hereinafter referred to as comparative reflective films) 1 to 4 and conventional aluminum alloy reflective films (hereinafter referred to as conventional reflective films) 1 was formed. As a result of analyzing the outermost surface layer of these reflective films by XPS (X-ray photoelectron spectroscopy), the outermost barrier layer contains Mg and O in addition to the main component Al, but there is almost no Ce. Mg is concentrated in the outermost surface layer, the concentration is higher than the inside of the film, Al in the outermost surface layer is present at least partially as an oxide as judged by the chemical shift of the peak due to 2p electrons, And the outermost oxide layer was found to have a thickness of about 1.5-3.5 nm. The state of Mg could not be clearly determined from the peak shift, but Mg was concentrated and present at almost the same position as the depth direction distribution from the surface of the Al oxide. Since it is known that the standard free energy of formation is lower than that of Al oxide, it is considered that Mg is likely to exist as a composite oxide of Al and Mg.

The following tests were performed on the reflective films 1 to 10 of the present invention, the comparative reflective films 1 to 4 and the conventional reflective film 1 having a thickness of 100 nm formed as described above.
(A) Initial reflectivity test of Al alloy reflective film The reflectivities of the present reflective films 1 to 10, the comparative reflective films 1 to 4, and the conventional reflective film 1 immediately after fabrication are measured with a spectrophotometer at a wavelength of 550 nm. The results are shown in Table 2.

(B) Moisture resistance test The reflective films 1 to 10, comparative reflective films 1 to 4 and the conventional reflective film 1 of the present invention are each held for 100 hours in a constant temperature and humidity chamber having a temperature of 50 ° C. and a relative humidity of 95%. The reflectance was measured with a spectrophotometer at a wavelength of 550 nm, and the results are shown in Table 2. Further, the appearance of the film after holding was visually observed to check for the occurrence of pitting corrosion, and the results are shown in Table 2.

(C) Alkali resistance test A 1% by mass KOH aqueous solution was dropped with a dropper on the reflective films 1 to 10, comparative reflective films 1 to 4 and the conventional reflective film 1 of the present invention, and the KOH aqueous solution was washed after 3 minutes from the dropping. Then, the dripping portion was visually observed, and the results of dissolution of the film with the KOH aqueous solution are shown in Table 2.

  From the results shown in Tables 1 and 2, the present reflective films 1 to 10 obtained by performing sputtering using the present inventive targets 1 to 10 of the present invention are performed by performing sputtering using the conventional target 1. Compared to the obtained conventional reflective film 1, the initial reflectance is not much different, but the reflective films 1 to 10 of the present invention have less decrease in reflectance after the moisture resistance test than the conventional reflective film 1, and the moisture resistance test. It turns out that it does not become cloudy later and is excellent in the corrosion resistance to the KOH aqueous solution. However, the reflective film produced using comparative targets 1 to 4 containing Mg, Ce and unavoidable impurities outside the scope of the present invention has a decreased reflectance after the moisture resistance test, and the film becomes clouded or pitting corrosion occurs. It can be seen that undesirable characteristics such as occurrence and elution in the aqueous KOH solution appear.

It is a partial cross section figure of the reflector with which the vehicle lamp of this invention is equipped. It is a partial cross section figure of the reflector with which the conventional vehicle lamp is comprised. It is sectional drawing of a vehicle lamp.

Explanation of symbols

1 reflector, 2 light source, 3 lens, 4 base material, 5 undercoat, 6 reflective film made of aluminum or aluminum alloy film, 7 protective film, 8 barrier film

Claims (2)

A vehicle lamp having a reflector in which an aluminum alloy reflective film is formed on the surface of a base material or an undercoat formed on the base material,
The aluminum alloy reflective film in the reflector is made of an aluminum alloy having a composition of Mg: 0.3 to 10% by mass, Ce: 2 to 10% by mass, the balance being made of Al and inevitable impurities, and the outermost surface thereof. A vehicular lamp having a reflector excellent in corrosion resistance, comprising a barrier film made of an oxide containing Al and Mg and substantially free of Ce. 2. The corrosion resistance according to claim 1, wherein the outermost surface of the aluminum alloy reflective film in the reflector is exposed to the outside, and a protective film is not formed on the outermost surface of the aluminum alloy reflective film. A vehicular lamp with an excellent reflector.

Images