JPH087643A - Luminaire having photocatalytic function - Google Patents

Abstract

PURPOSE:To provide both a photocatalytic function and an illuminating function, and enable sterilization, deodorization and stainproofing by using a metallic board where an oxide particulate layer is formed on the surface by performing positive electrode oxidation processing, as a light reflecting plate. CONSTITUTION:An oxide semiconduactor particulate layer 4 is formed on a surface by performing positive electrode oxidation processing on the surface of a metallic plate 2 of zinc or zinc alloy or the like. This is arranged in the vicinity of a light source 1 as a light reflecting plate. This reflecting plate has photocatalytic activity, and performs sterilization, and decomposes malodorous gas, an organic substance or the like. The light reflecting plate may be produced by forming a metallic layer on resin 2 such as glass, wood or plastic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device having a sterilizing, deodorizing and antifouling function by photocatalytic activity,
More specifically, the present invention relates to a lighting device using a reflection plate having photocatalytic activity.

[0002]

2. Description of the Related Art Since titanium oxide and zinc oxide are semiconductors, application as a photocatalyst having photocatalytic activity has been reported. The photocatalytic activity means that the oxide semiconductor fine particles are excited by absorbing light (generally, ultraviolet ray) having energy larger than the band gap, and the generated electrons and holes exchange electrons with the substance adsorbed on the particle surface. Is an activity to oxidize or reduce the adsorbed substance to decompose it. By using this principle, it is possible to decompose bacteria, malodorous gas, organic matter and the like attached to the surface of the oxide semiconductor, and obtain effects such as sterilization, deodorization and antifouling.

A number of patents have been filed and published for deodorizers, air purifiers, refrigerators, etc. that utilize a combination of a photocatalyst and an ultraviolet light source. In these, the light source is a light source for activating the photocatalyst. It has little use if it does not have a substance to be decomposed. Further, the use of a combination of a photocatalyst and an ultraviolet light source is disclosed in JP-A-4-307065, JP-A-4-307066, etc., but in these cases as well, by irradiating light, the inside of the room is slightly increased or decreased. However, it is indirect lighting, and it is not practical to use it as a lighting fixture.

Further, a method of applying fine zinc oxide particles to a fluorescent lamp to absorb ultraviolet rays is disclosed in JP-A-2-216751, JP-A-2-253554, and JP-A-3-209.
As disclosed in Japanese Patent Laid-Open No. 55-55, this is for the purpose of absorbing only ultraviolet rays, and zinc oxide does not have a photocatalytic function because it is covered with paint. Further, there is no suitable technique so far for the photocatalyst film having a high reflectance in the visible region and the fixing method thereof.

[0005]

A luminaire having both a photocatalytic function and a lighting function is provided by providing a reflector having a semiconductor fine particle layer having a high reflectance in the visible region fixed on the surface in the vicinity of a light source which also emits ultraviolet rays. Will be provided.
If you use such a lighting fixture, it will also serve as lighting in the building,
It enables sterilization, deodorization, and antifouling inside the building. For that purpose, the semiconductor fine particles can be firmly fixed without being covered with a resin or the like, and the semiconductor fine particle layer has a high ultraviolet absorbing ability and a high reflectance in the visible region. As a method of fixing the semiconductor fine particles, a method of dispersing and fixing it in an organic substance such as a resin or a paint can be considered. In this case, since the oxide fine particle surface is covered with the resin or the like, the substance to be decomposed is a semiconductor. Because it cannot contact the particles, it cannot transfer electrons or holes,
No photocatalytic function occurs. Further, there are methods of forming a semiconductor oxide film by a sol-gel method or a sputtering method, but the film obtained by these methods has a high light transmittance in the visible region and appears transparent.

[0006]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have conducted anodization treatment on a metal plate, a metal sheet, a metal foil or the like to form an oxide fine particle layer on the surface thereof. By forming a metal plate, a metal sheet, a metal foil, etc. obtained by the above treatment, which has a structure in which light is reflected, and is arranged in the vicinity of a light source that also emits ultraviolet rays, a photocatalytic function and a lighting function are obtained. The present invention has been completed by finding that a luminaire having both and can be obtained.

That is, the luminaire having a photocatalytic function of the present invention is characterized in that a substrate having an oxide semiconductor fine particle layer obtained by anodizing a metal as a surface layer is used as a light reflecting plate.

The substrate used as the light reflection plate in the present invention has an oxide semiconductor fine particle layer obtained by anodizing the metal on the surface thereof, and its shape is that of a reflection plate suitable for each lighting fixture. The shape. Regarding the material of the substrate, even if the whole is a metal, or most of it is a non-metal material such as glass, plastic, wood, reinforced paper, cloth, etc., and has a metal layer on it, and on top of that there is oxide semiconductor fine particles. There may be layers.

In the present invention, the metal to be anodized to form the oxide semiconductor fine particle layer includes a metal, an alloy, or a metal or alloy applied to the surface by plating, thermal spraying, etc. Any material may be used as long as the oxide semiconductor fine particle layer is formed by the treatment, and examples thereof include titanium, zinc, tin, iron and the like, or alloys containing those metals. For example, a titanium plate may be used to form the titanium oxide semiconductor fine particle layer, and a zinc plate or a zinc plated plate may be used to form the zinc oxide semiconductor fine particle layer. In particular, with zinc, it is easy and inexpensive to perform zinc plating on an iron plate (so-called galvanized sheet) by molten plating, electroplating or the like, and a good quality film can be obtained by anodic oxidation. The plating plate may be molten plating, electric plating, electroless plating, or the like. Similar results can be obtained by spraying a metal on the surface of resin, glass or the like and then subjecting this to anodization.

The anodizing treatment is carried out under the conditions generally used in the past. Fine particles of oxide are produced by applying an electrolytic voltage to a metal plate, foil or the like in an electrolytic solution and anodizing. A film consisting of Since the anodic electrolytic treatment does not require heating such as the sol-gel method and vacuum such as sputtering, the fine particle layer can be easily and inexpensively formed. The film obtained by anodizing treatment is strong, does not peel off even when the plate is bent, and can be processed into the shape after film formation. In addition, a white film made of fine particles can be formed by selecting the composition of the electrolytic solution and the electrolysis conditions, and the reflectance in the visible region is high, and the film is suitable as a reflector.

The substrate used as the light reflection plate in the present invention may be one in which an oxide semiconductor fine particle layer is formed on the surface by anodizing after processing into a shape of the reflection plate suitable for each lighting fixture, or Even if processed into the shape of a reflector suitable for each lighting fixture after forming an oxide semiconductor fine particle layer on the surface by anodizing treatment,
Alternatively, a metal foil, thin metal sheet, or other flexible or flexible metal material that has been subjected to anodizing treatment to form an oxide semiconductor fine particle layer on the surface of the foil or sheet is used as a reflective material suitable for each lighting fixture. It may be attached to a substrate processed into a plate shape. The shape of the "light reflection plate" is preferably a plate shape in order to obtain a high reflectance,
For dimming, scattering, etc., corrugated plate other than flat plate, mesh,
It may be cylindrical, cone-shaped, concave, or the like.

In order for the luminaire having the photocatalytic function of the present invention to function effectively, the illuminating light source must emit visible light and ultraviolet light. As such a light source, all kinds such as a mercury lamp, a black light and a fluorescent lamp are conceivable, and the shape of the light source may be any shape such as a rod shape, a spherical shape, a ring shape and the like.

In order for the luminaire having the photocatalytic function of the present invention to function effectively, it is necessary that the light reflecting plate thereof be arranged near the light source. "Near the light source" means
Although it depends on the position where the visible light and the ultraviolet light emitted from the light source can be sufficiently irradiated, that is, depending on the shape of the light source, it means within 1 meter, preferably within 0.5 meter from the light source in lighting used in a building.

[0014]

【Example】

Example 1 Degreased and washed zinc plate (10 cm x 10 cm, thickness 1 m
m, the backside is coated with vinyl tape) in an electrolytic solution (8 g of sodium hydroxide, 16 g of sodium nitrate, 1 liter of water), which is used as an anode, and a stainless steel plate (10 cm x 10 cm) is used as a cathode. The distance was set to 10 cm, and a DC voltage of 20 V was applied for 20 minutes for anodization. Thereafter, this was washed and dried to obtain a zinc oxide coated plate. The surface of this zinc oxide coated plate is white,
In addition, it was confirmed by X-ray diffraction and transmission electron microscope observation that fine particles (average particle size of less than 20 nm) of zinc oxide were deposited. The thickness of the coating was about 1 μm.

When the reflection spectrum of this coating was measured, it was found that light in the visible region was well reflected and that ultraviolet rays having a band gap of 380 nm or less were completely absorbed. This film has sufficient performance as a visible light reflector.

Sealed glass container (volume 10 liters,
Installed a lighting device with a daylight color fluorescent lamp (15W) connected inside (with gas injection sampling port), and with the above-mentioned zinc oxide coating of 5 × 20 cm at a position 2 cm closest to the surface of the fluorescent lamp tube. Installed the board. The photocatalytic activity was measured using the luminaire including the fluorescent lamp and the zinc oxide coated plate.

Acetaldehyde gas was placed in this sealed container, the fluorescent lamp according to the present invention was turned on to decompose acetaldehyde, and the amount of decomposition was measured by gas chromatography. Here, acetaldehyde was used as the gas to be treated, but this is generally used as an index for decomposing ability of bacteria and organic substances. Therefore, the results obtained here correspond to sterilizing ability and deodorizing ability. When acetaldehyde gas was injected into the container at 50 ppm and ultraviolet irradiation was started, it was possible to reduce it to 5 ppm after 60 minutes, and it was confirmed that it was decomposed by the photocatalyst.

Example 2 As shown in FIG. 1, the surface (inner surface) on the fluorescent lamp side of the reflector (12 cm × 44 cm) of a commercially available fluorescent lamp for a desk lamp using a vinyl chloride resin plate 2 as a reflector. 2), zinc metal particles (average particle size 3 μm) were sprayed with argon to form a zinc metal layer 3. The electrolytic solution used in Example 1,
The zinc oxide semiconductor fine particle layer 4 was formed on the surface by anodizing treatment using electrolysis conditions. This reflector was not completely anodized because it was slightly oxidized during spraying, but it was white. This fluorescent lamp reflector and fluorescent lamp section 1
Was placed in a closed glass container, and the photocatalytic decomposition rate of acetaldehyde gas at 50 ppm was measured under the conditions shown in Example 1. As a result, it was possible to reduce the rate to 5 ppm after 120 minutes.

[0019]

The luminaire according to the present invention acts as a photocatalyst when the gas to be decomposed comes into contact therewith, but does not substantially reduce the illuminance of conventional fluorescent lamps, etc., and has sufficient brightness as a luminaire. Have Further, since the semiconductor fine particles absorb ultraviolet rays, deterioration of the illuminated object due to ultraviolet rays can be prevented by using the device of the present invention. The lighting device according to the present invention is for sterilizing display items such as fresh foods,
It is useful for deodorization and prevention of deterioration due to ultraviolet rays.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment of a lighting fixture having a photocatalytic function of the present invention.

[Explanation of symbols]

 1 Light source (fluorescent lamp) 2 Vinyl chloride resin plate 3 Zinc metal layer 4 Zinc oxide semiconductor fine particle layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhide Yamaguchi 1333-2 Ageo City, Saitama Prefecture, Mitsui Mining & Smelting Co., Ltd. (72) Inventor Akira Fujishima 710-5, Nakamaruko, Nakahara-ku, Kawasaki City, Kanagawa Prefecture (72) Inventor Kazuhito Hashimoto 10 Minami-Kosugaya Houses, 2 houses, 506, Kosugaya-cho, Sakae-ku, Yokohama-shi, Kanagawa 506

Claims (2)

[Claims] 1. A luminaire having a photocatalytic function, wherein a substrate having an oxide semiconductor fine particle layer obtained by anodizing a metal as a surface layer is used as a light reflecting plate. 2. The metal is zinc or a zinc alloy.
A luminaire having the described photocatalytic function.