JP2698623B2 - Reflector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a high-pressure discharge lamp typified by a mercury lamp or the like, and in particular, to a reflector such as a lighting fixture using a lamp that generates a large amount of ultraviolet light, The present invention relates to a reflector having an effect of preventing an illumination object from deteriorating ultraviolet rays.

[Conventional technology]

2. Description of the Related Art Conventionally, as a method of manufacturing a reflecting mirror attached to a lighting apparatus using a high-pressure discharge lamp, there is the following method.

After the metal substrate (Al, stainless steel, Fe, etc.) is polished with a cloth, electrolytic polishing or chemical polishing is performed, and then anodized.

An organic or inorganic protective coating film is formed instead of the alumite processing in the above method.

A base material made of metal, glass, ceramic, plastic, or the like is coated with a base coat if necessary (essential for a metal base material), and then a glittering metal (Al, Ag, etc.) film is formed by vapor deposition. To form an organic or inorganic protective coating film.

Instead of the protective coating film of the above method, a transparent dielectric thin film (a protective film made of SiO ₂ , Al ₂ O ₃ , MgF ₂ or the like) is formed by vapor deposition.

As the transparent dielectric thin film (protective film) of the above method,
An optical multilayer thin film (for example, a reflection enhancing film, a heat ray cut film, an ultraviolet ray cut film, etc.) is formed.

The reflecting mirror formed as described above is required to have a heat resistance of about 200 ° C. or more because the temperature of the lamp during operation becomes high. Therefore, the types of paints and the like used for the base coat and the protective coating film are, of course, limited to those that do not cause thermal degradation at about 200 ° C. In addition, since the amount of ultraviolet radiation is large, a constituent material that is not easily deteriorated by ultraviolet rays is selected.

[Problems to be solved by the invention]

As described above, the reflecting mirror reflects all light in the ultraviolet, infrared, and visible regions of the lamp light component. In other words, the reflected light also contains ultraviolet rays and heat rays that degrade the irradiated object, causing various problems. Therefore, it is desired to manufacture a reflecting mirror that does not particularly irradiate ultraviolet light in the lamp light. According to the above-described conventional method, there are the following two methods, each having the following problems. Is left.

(A) A transparent protective coating film containing an ultraviolet absorber is formed on the reflecting mirror surface (reflection surface); the ultraviolet absorber itself decomposes as it is used. The effect disappears.

(B) Forming an optical multilayer thin film (ultraviolet cut filter) on the reflecting surface; the shape of the reflecting mirror is usually a hemispherical parabolic shape. , 15 layers or more) is not easy. Further, since the incident angle of the lamp changes, it is difficult to cut off the ultraviolet rays by the interference action. In addition, manufacturing costs are high.

In view of the above circumstances, the present invention is provided for lighting equipment that uses high-pressure discharge lamps such as mercury lamps, particularly lamps that generate a large amount of ultraviolet light, and efficiently emits ultraviolet light generated from the lamp without deterioration even after long-term use. An object of the present invention is to provide a reflecting mirror that absorbs well and has an effect of preventing the irradiated object from being deteriorated by ultraviolet rays.

[Means for solving the problem]

In order to solve the above problems, the reflecting mirror according to the present invention has a transparent zinc oxide film absorbing ultraviolet light having a thickness of 500 to 300.
0 ° so that it is provided on the reflection surface.

The zinc oxide film may be formed in the form of a low-refractive-index material film provided in advance on the reflection surface.

Further, a transparent protective film may be formed on the zinc oxide film.

Further, a low refractive index material film is formed on the zinc oxide film,
A high-refractive-index material film may be further formed on the low-refractive-index material film.

[Action]

Zinc oxide has the property that it has a very high absorptivity for ultraviolet light of 3080 nm or less, but transmits visible light without absorbing it. Therefore, by providing the zinc oxide film (thin film), the visible light is reflected without being lost, while the ultraviolet light is hardly cut by the zinc oxide film and does not reach the irradiated object. UV degradation is prevented. At the same time, zinc oxide has excellent weather resistance,
It has durability and the like, and its effect is not lost even if it is used for a long time.

The thickness of this zinc oxide film is 500-3000 mm (dry film thickness;
The same applies hereinafter), so that a particularly excellent ultraviolet absorbing effect is exhibited without causing absorption of visible light.

If a low-refractive-index material film is provided on the reflecting surface in advance, and the zinc oxide film is formed thereon, an enhanced reflection effect can be obtained because the zinc oxide film corresponds to a high-refractive-index material film. Visible light reflectance can be increased.

Further, by forming a transparent protective film on the zinc oxide film, the surface hardness can be improved as compared with the case of using the zinc oxide film alone, and the fear of scratching during cleaning or the like can be eliminated. In addition, the chemical resistance (acid resistance, alkali resistance) of the reflecting mirror can be improved.

Furthermore, by forming a low-refractive-index material film and a high-refractive-index material film in this order on the zinc oxide film,
As with the protective film, the surface hardness and corrosion resistance of the reflector can be improved. Further, the visible light reflectance can be improved by the same enhanced reflection effect as described above.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 to 3 each schematically show a cross section of an embodiment of the reflecting mirror according to the present invention in which a zinc oxide film 5 is provided on a reflecting surface of a substrate 1. FIG.

As the base material 1, a plate-like metal material made of Al, Al alloy, Fe, Fe alloy, stainless steel, etc., is formed into a predetermined reflecting mirror shape by a forming method such as press forming, spatula drawing and the like.
Alternatively, glass, ceramics, plastic (for example, polycarbonate, nylon, polyimide, etc.) which is finished to a predetermined reflecting mirror shape by die molding (injection molding, press molding, etc.) is preferably used. here,
In the case of plastic, it is necessary to select a plastic that can withstand the heat from the lamp and has excellent heat resistance.

On the reflecting surface (surface) of the base material 1 of the reflecting mirror formed as described above, for example, a method as described below is used.
Apply mirror finish.

As shown in FIG. 1 (a), after the surfaces of the metal substrates (for example, aluminum) 1 listed above are polished with a cloth, mirror polishing is performed by electrolytic polishing or chemical polishing. Next, an Al ₂ O ₃ film 2 is formed by alumite processing as a protective film for suppressing corrosion of a metal base material such as aluminum. The alumite protective film also corresponds to the low-refractive-index material film (7), and can be expected to have an enhanced reflection effect as described later. However, formation of this protective film after the mirror surface treatment may be omitted, or clear coating or the like may be performed instead of alumite processing.

As shown in FIG. 1 (b), after applying a base coat to the surface of the base material 1 such as the above-mentioned metal or glass, ceramics, plastic, etc. to form a coating film 3, the glittering metal (Al, Ag,
(Cr, Ni, etc.) film 4 is formed by vapor deposition.

As shown in FIGS. 2 and 3, the glitter metal film 3 is formed directly on a substrate 1 such as glass, ceramics, or plastic.

After the above mirror finishing, a zinc oxide film 5 for absorbing ultraviolet light, which is a feature of the present invention, is formed on the finished surface, that is, the reflecting surface. When only the reflection enhancement is considered, a low-refractive-index material film made of SiO ₂ , MgF ₂ , Al ₂ O ₃ or the like is formed in advance on the mirror-finished surface by vapor deposition, and zinc oxide is formed thereon. A film (corresponding to a high refractive index substance) can be laminated. At that time, the thickness of the low refractive index material film is 650 to 110
It is preferable that the thickness is 0 ° and that the thickness is about 500 to 1000 ° for a zinc oxide film.

Examples of the method for forming the zinc oxide film 5 include a vacuum deposition method, a sputtering method, an ion-assisted deposition method,
Various physical vapor deposition methods (PVD) such as ion plating
During film formation, substrate heating (room temperature to 400 ° C) and O
_2. Add Ar gas and so on. In addition, the zinc oxide film 5 may be formed by a chemical vapor deposition method (CVD) or a dipping method, and is not particularly limited.

The above dipping method is performed as follows. Further, a raw material compound which becomes zinc oxide upon firing is dissolved in an appropriate solvent to prepare a coating liquid. Then
The mirror-finished substrate 1 is immersed in the coating liquid, pulled up at a constant speed, dried and fired at a high temperature, and a transparent zinc oxide film is formed on the reflection surface of the substrate 1. 5 is formed. Note that the zinc oxide film 5 can be formed by using the same coating liquid and applying the same by spraying or the like. That is, if uniform coating is performed on the reflection surface of the substrate 1, a coating method or the like may be used.
There is no particular limitation.

The raw material compound in the coating liquid is not particularly limited as long as it is a compound containing zinc (= zinc compound). Examples of the organic zinc compound include: (1) zinc octylate, 2-ethylhexanoic acid Carboxylates (metal soaps) such as zinc and zinc naphthenate; (2) chelate compounds (complexes) such as zinc acetylacetonato; (3) various zinc alkoxides; (4) organic zinc compounds such as dialkyl zinc and diphenyl zinc And the like are mentioned as the most preferred examples. In addition, as inorganic materials, common salts such as zinc nitrate and zinc chloride are similarly used. These zinc compounds can be used alone or in combination.

Examples of the solvent for dissolving the zinc compound include (A) aromatic hydrocarbons (benzene, toluene, xylene, cymene, naphthalene, etc.), (A) alcohols (isopropyl alcohol, butyl alcohol, etc.), (C) ketones (Acetone, acetylacetone, diethylketone, etc.), (d) essential oil-based terpene hydrocarbons (dipentene, α-
Pinene, turpentine, myrcene, etc.) are preferably used, but are not limited thereto, and any solvent may be used in view of the boiling point, leakage to the substrate, and solubility of the zinc compound as a solute. Can be used.

The solvent may be a single solvent composed of one of the above compounds and the like, but if it is a low-boiling solvent, a film to be formed may become cloudy. It is preferable to use a solvent mixture adjusted with the above.
In addition, for the same reason of increasing the boiling point,
~ (D) as a solvent other than unsaturated fatty acids (for example,
It is also preferable to partially add oleic acid, linoleic acid, etc.).

Further, if necessary, other various additives can be blended in the coating liquid. For example, it is also preferable to add a leveling agent such as screen oil in order to improve the state of application to the substrate.

Although the concentration of the coating solution is not particularly limited, it is most preferably approximately 5% by weight in terms of ZnO concentration as a rough guide. If the concentration is too high, the resulting film may become cloudy or peel off, while if it is too low, the desired film thickness required for absorbing ultraviolet light may not be obtained. Can be seen.

The baking conditions (temperature, time, etc.) are not particularly limited, either.
It is preferable to set it appropriately. To give a concrete example,
When using the zinc compound as described above, it is generally preferable to perform baking at a temperature of 500 ° C. or more for about 30 to 60 minutes. Thus, the decomposition and oxidation reaction of the zinc compound are completely performed, and as a result, a transparent zinc oxide film 5 is formed on the base material.

The thickness of the obtained zinc oxide film 5 is 500 to 3000 °. If the angle is less than 500 °, a sufficient ultraviolet ray absorbing effect may not be obtained. On the other hand, if it exceeds 3000 °, visible light is absorbed and the reflectance tends to decrease.
Here, the zinc oxide film 5 may have a single-layer structure or a multilayer structure in which several layers are stacked. As described above, since the number of stacked films is not limited to one layer, for example, when one layer has a low UV cut efficiency (the film is too thin), many layers are stacked to form a multilayer film. You can also earn thickness. If the total thickness of the zinc oxide thin film thus obtained is 500 mm or more, the effects of the present invention can be sufficiently obtained.

Incidentally, as the zinc oxide in the present invention, usually,
It is preferable to use one having a ZnO composition, but the present invention is not limited thereto, and those having different oxidation forms such as Zn ₂ O may be used together or alone.

FIG. 5 shows the spectral reflectance characteristics of the reflecting mirror coated with the zinc oxide film 5 by the above method. As shown in FIG.
Compared to the case of only a vapor-deposited film (dashed line in the figure), the case with a zinc oxide film (solid line in the figure) cuts ultraviolet rays below 380 nm very well, but the reflectance in the visible light range is slightly lower. Has become. On the other hand, the zinc oxide film has a low surface hardness and is easily scratched. In addition, zinc acid is an amphoteric oxide and has the property of being easily dissolved in both acidic and alkaline solutions. When used as a reflector, such a problem may be a problem.

In order to avoid the above problems, a transparent protective film 6 may be provided on the zinc oxide film 5 as shown in FIG. The transparent protective film 6 may be a transparent derivative film made of SiO ₂ , Al ₂ O ₃ , MgF ₂ or the like, or a transparent coating made of a heat-resistant clear coating such as a silicone-based or organic silicate-based coating. It may be a film, and is not particularly limited. An arbitrary method may be adopted as the forming method. For example, the former (derivative film) is easily formed by a vacuum deposition method or the like, and the latter (coating film) is easily formed by a normal coating method. Can be done.

The thickness of the transparent protective film 6 is preferably about 1 to 10 μm. If the thickness is too large, the cost is increased. In addition, visible light is absorbed by the protective film 6 and the visible light transmittance is reduced, and therefore, the visible light reflectance may be reduced. , The corrosion resistance deteriorates,
Further, there is a tendency that visible light is absorbed by the interference effect. However, the present invention is not limited to the above range, and may have a multilayer structure.

On the other hand, as shown in FIG. 3, SiO ₂ , M
A low-refractive-index material film 7 such as gF ₂ or Al ₂ O ₃ is formed.
The high-refractive-index material films 8 such as O, ZrO ₂ , CeO _2, etc., can also be formed by vapor deposition or the like.

By forming the films 7 and 8 having different refractive indexes in this order, as described above, the reflection increasing effect is obtained and the reflectance in the visible light range is increased. In order to achieve the maximum increase, it is preferable that the thickness of the low refractive index material film 7 is about 650 to 1100 ° and the thickness of the high refractive index material film 8 is about 500 to 1000 °. The films 7 and 8 are not limited to one layer each, but may be alternately stacked in multiple layers.

As described above, by providing at least the zinc oxide film on the reflecting surface of the base material, a reflecting mirror that can solve the problem of the present invention can be realized. It goes without saying that the reflecting mirror according to the present invention is not limited to the one embodiment.

Next, more specific examples of the present invention will be described together with comparative examples.

-Example 1-A parabolic aluminum substrate molded product having a diameter of 350 mm and a depth of 220 mm obtained by spatula drawing was subjected to feather cloth polishing, then electrolytic polishing, and further subjected to anodizing by an anodizing method to obtain a film. An Al ₂ O ₃ film having a thickness of 0.1 μm (corresponding to a low refractive index material film) was formed. Next, in a vacuum of ^{1 × 10 θ 5 ~5 × 10} θ 5 Torr, ( see FIG. 1 (a)) which is deposited a ZnO by an electron beam evaporation method (film thickness 1000 Å), thereby completing the reflection mirror.

-Example 2 After a parabolic aluminum substrate molded product having a diameter of 580 mm and a depth of 300 mm was degreased and dried, a silicone paint containing polydimethylsiloxane as a main component was used as a base paint to a thickness of 10 µm.
m and baked at 200 ° C. for 60 minutes. Thereafter, Al was deposited (thickness: 1000 mm) to give a mirror finish. Next, ZnO is deposited by an electron beam deposition method (film thickness: 1500
Å), the reflecting mirror was completed (see FIG. 1 (b)).

- while heating the hard glass substrate which is Example 3 pressed into 100 ° C., the ^{1 × 10 θ 5 ~5 × 10} θ 5 Torr resistance heating deposition method in a vacuum of, Al film (HazamaAtsushi 1000 Å) Formed. Then, in the same vacuum chamber, a ZnO film (thickness: 1000 mm) is formed by electron beam evaporation, and a SiO ₂ transparent protective film (1.5 μm in thickness) is further formed thereon by electron beam evaporation. The reflector was completed (see FIG. 2).

-Example 4-An Al film having a thickness of 1000 mm was formed on a press-formed hard glass substrate in the same manner as in Example 3 described above, and then taken out, and a coating solution having the following composition (hereinafter,% is% by weight) Represents); Was applied by spray coating. This is dried at 150 ° C. for 10 minutes, and baked at 500 ° C. for 30 minutes to obtain a ZnO film (film thickness: 2000
Å) was obtained. Next, the same organic silicate paint was spray-coated, and then baked at 200 ° C. for 20 minutes to form a transparent protective film (about 2 μm thick) (see FIG. 2).

Example 5 In Example 3, the thickness of the SiO ₂ film was set to 950 °,
Furthermore, a TiO ₂ film (thickness: 60
Thus, a reflecting mirror having a low-refractive-index material (SiO ₂ ) film and a high-refractive-index material (SiO ₂ ) film formed on a ZnO film was formed (see FIG. 3).

Comparative Example 1 A reflecting mirror was produced in the same manner as in Example 2 except that the thickness of ZnO was changed to 300 °.

Comparative Example 2 A reflecting mirror was manufactured in the same manner as in Example 2 except that the thickness of ZnO was changed to 400 °.

Comparative Example 3 A reflecting mirror having an Al ₂ O ₃ film was produced in the same manner as in Example 1 except that the ZnO film was not formed (see FIG. 4A).

Comparative Example 4 A reflecting mirror having an Al vapor deposited film and a SiO ₂ transparent protective film was produced in the same manner as in Example 3 except that the ZnO film was not formed (see FIG. 4B). .

Spectral reflectance characteristics were evaluated for each of the reflector samples of the above Examples and Comparative Examples.

Spectral reflectance of each sample at 200 to 780nm (%)
Was measured using a self-recording spectrophotometer (U-3410, manufactured by Hitachi, Ltd.) to obtain a chart as shown in FIG. Based on this, the ultraviolet ray cut rate and the visible light reflectance were calculated by the following formulas.

★ UV cut rate (CP) ・ Calculate the area of B in Fig. 6.

・ As shown in the figure, the area of (A + B) is (380−200) nm × 100% = 18000, so the area of A can be obtained by (18000−B).

Therefore, the ultraviolet ray cut rate CP (%) is calculated by the following equation.

 CP = [A / (A + B)] × 100 = (18000−B) / 180 ★ Visible light reflectance (T) ・ Calculate the area of D in FIG.

 -The area of (C + D) is (780-380) nm x 100% = 40,000 as shown in the figure.

Therefore, the visible light reflectance T (%) is calculated by the following equation.

 T = [D / (C + D)] × 100 = D / 400 Table 1 shows the results.

As shown in Table 1, it was found that the reflecting mirror of the example in which the zinc oxide film was formed absorbs and cuts the ultraviolet light much better than the comparative example. It was also found that even when the zinc oxide film was formed, the same good visible light reflectance as that when the zinc oxide film was not formed could be maintained. Further, as shown in Examples 1 to 5, when the thickness of the zinc oxide film is about 500 to 3000 °, it is possible to obtain a reflector excellent in both the ultraviolet ray cut rate and the visible light reflectance. In Comparative Example 1, the thickness of the film was as thin as less than 500 °, so that the UV cut ratio was lower than in Examples 1 to 5. In Comparative Example 2, on the contrary, the thickness of the film exceeded 3000 °, Light reflectivity is decreasing.

〔The invention's effect〕

The reflecting mirror according to the present invention absorbs ultraviolet rays generated from the lamp very well by the action of the zinc oxide film, and thus has an excellent ultraviolet ray deterioration preventing effect on the irradiated object. Therefore, the reflecting mirror is useful when used in a lighting fixture using a high-pressure discharge lamp such as a mercury lamp, particularly a lamp that generates a large amount of ultraviolet light, and the effect of preventing the deterioration of ultraviolet light does not decrease with use. , Maintained at high altitude for a long time. At the same time, since the reflecting mirror of the present invention reflects visible light without absorbing it, it can be used effectively without loss of visible light.

If a zinc oxide film is formed on a low-refractive-index material film provided in advance on the reflection surface, a reflection-enhancing effect can be obtained, and the reflection mirror having a higher visible light reflectance can be obtained.

Further, by forming a transparent protective film on the zinc oxide film, a reflecting mirror having excellent surface hardness and corrosion resistance can be obtained. In addition, by forming an optical multilayer film having a reflection enhancing effect on the zinc oxide film, it is possible to obtain a reflecting mirror which is excellent in surface hardness and corrosion resistance and further has a good visible light reflectance.

[Brief description of the drawings]

FIGS. 1 (a) and (b), FIGS. 2 and 3 are schematic cross-sectional views schematically showing one embodiment of the reflector according to the present invention, and FIGS. 4 (a) and (b). ) Is a schematic cross-sectional view schematically showing a conventional reflecting mirror, FIG. 5 is a graph showing a difference in spectral reflectance characteristics depending on the presence or absence of a ZnO film, and FIG. 6 is an ultraviolet cut rate and a visible light in Examples and Comparative Examples. 5 is a graph illustrating a method for calculating a reflectance. 1 ... substrate, 5 ... zinc oxide film, 6 ... transparent protective film, 7
............ Low refractive index material film, 8 ... High refractive index material film

Claims (4)

(57) [Claims] 1. A transparent zinc oxide film that absorbs ultraviolet light has a thickness
A reflector provided on the reflective surface at 500-3000mm. 2. The reflecting mirror according to claim 1, wherein a zinc oxide film is formed on a low refractive index material film provided in advance on the reflecting surface. 3. The reflecting mirror according to claim 1, wherein a transparent protective film is formed on the zinc oxide film. 4. The reflecting mirror according to claim 1, wherein a low refractive index material film is formed on the zinc oxide film, and a high refractive index material film is further formed on the low refractive index material film.