JP5942283B2 - Reflector for lighting equipment - Google Patents

Description

  The present invention relates to a reflector for a lighting fixture.

  Since silver is excellent in visible light reflectivity, it is used for a reflector for lighting equipment. In particular, in a reflector having a deep shape such as a downlight, since light is repeatedly reflected, it is very effective to use a material having a high reflectance such as silver as the reflector.

  FIG. 4 shows a conventional reflector 100 for a lighting fixture. This reflector 100 for a lighting fixture has a top coat layer 101, ITO (indium tin oxide) 102, a silver film 103, an undercoat layer 104, and a base material 105. They are stacked in order.

  However, since the silver film 103 is a chemically unstable substance, there is a problem that it is easily discolored. The reflector 100 for lighting fixtures in which the silver film has been discolored not only deteriorates in appearance but also significantly reduces illumination efficiency due to a decrease in reflectance.

  Various studies have been conducted on the mechanism of silver discoloration, but light, especially UV (ultraviolet rays), heat, and atmospheric moisture, sulfurous acid gas, hydrogen sulfide, ammonia, and other gases are the main causes of discoloration. It is considered that the cause is that these discoloration causes interact to change silver into a brown or black compound such as silver sulfide or silver oxide.

  That is, as shown in FIG. 5, UV that reaches the undercoat layer 104 or the base material deteriorates the resin of the undercoat layer 104 or the base material, so that hydroxy radical (.OH) or peroxy radical (.OR) Is generated. It is presumed that discoloration occurs due to the silver oxide generated by the generated radicals.

In Patent Document 1, there is a “window” of transmittance in the UV region having a wavelength of about 325 nm on a silver thin film, and UV transmitted through the “window” deteriorates the undercoat near the interface with silver. Have been described.
In addition, when the film thickness of the silver film was thin, this inventor confirmed that the "window" of the transmittance | permeability exists in UV region with a wavelength near 320 nm. It is known that 320 nm UV is also present in fluorescent lamps and HID (High Intensity Discharge) lamps used as light sources.

  FIG. 6 shows the UV intensity characteristics of a fluorescent lamp as an example. It can be seen that in addition to the peak at a wavelength of 365 nm that is UV-A, there is a peak at a wavelength of 315 nm that is UV-B, which is close to the “window” region of the transmittance of the silver film.

  Therefore, in order to prevent deterioration of the undercoat layer or the base material due to the UV near 320 nm that has passed through the silver film, a sufficiently thick silver film may be formed so as not to create a “window” of transmittance in the silver film.

However, as shown in FIG. 7, in general lighting fixtures 110, the reflector 115 has many three-dimensional shapes, and it is extremely difficult to manufacture a thick silver film uniformly on the entire inner surface. There is a problem of being.
In FIG. 7, reference numeral 111 denotes a main body, 112 denotes an inverter, 113 denotes a socket, 114 denotes a lamp, and 116 denotes a leaf spring.

  FIG. 8 shows a film thickness distribution according to the position of the reflector 115 when a silver film is formed on the inner surface of the reflector 115 in the lighting fixture 110 shown in FIG. There is a film thickness difference of about 6 to 10 times between the lower part and the upper part of the reflecting plate 115, and the closer to the lamp 114 as the light source and the upper part of the reflecting plate 115 having a higher UV intensity, a “window” of transmittance is generated. It turns out that it becomes the film thickness to make.

Patent Document 2 describes that heat resistance and moisture resistance are improved by sandwiching a silver film with a transparent oxide film. As the transparent oxide film, metal oxide, silicon oxide, aluminum oxide, titanium oxide, tantalum of ITO, ZnO (zinc oxide), IZO (indium zinc oxide), and SnO ₂ (tin oxide) Oxides, silicon nitrides, aluminum nitrides, titanium nitrides, and tantalum nitrides are mentioned. Moreover, said film thickness shall be 1-20 nm.

  Since the reflector for lighting fixtures is irradiated with light containing high-intensity UV, it is essential to improve weather resistance. As shown in FIG. 9, when the film thickness of the silver film is about 170 nm or less, a “window” of transmittance having a peak at a wavelength of 320 nm appears. That is, UV emitted from the light source passes through the silver film and reaches the undercoat layer or the substrate surface. As the film thickness of the silver film decreases, the “window” increases in both wavelength range and transmittance. Accordingly, the UV load on the undercoat layer or the substrate is increased.

  FIG. 9 is a diagram showing the film thickness dependence of the silver film transmission spectrum in a silver film in which silver having a purity of 99.99% is formed on a quartz substrate by sputtering, and the horizontal axis indicates the wavelength of UV, The vertical axis represents the transmittance.

Japanese Patent Laid-Open No. 61-154942 (upper left column on page 3) JP 2001-296212 A (Claim 6, paragraph 0030)

  Conventional reflectors for lighting fixtures have a problem that the silver film changes color.

  The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide a reflector for a lighting fixture that can suppress discoloration of a silver film.

The reflector for lighting equipment of the present invention has a base material, a reflective layer that has a reflective surface that reflects visible light that contains silver, and has a thickness that can cause a transmittance window having a peak at a wavelength of 320 nm. A reflective surface side protective layer that is disposed on the reflective surface side of the reflective layer and has weather resistance and gas barrier properties, and is disposed on the opposite side of the reflective surface of the reflective layer, compared to the reflective surface side protective layer. A non-reflective surface side protective layer that cuts light with a wavelength of 400 nm or less and suppresses deterioration of the substrate by being thickened, and the non-reflective surface side protective layer and the reflective surface side protective layer are both indium tin oxide (ITO), the thickness of the reflective layer is set to 20nm~1000nm Rutotomoni, the reflective layer has a thickness comprises at least the following portions 170 nm, the reflecting surface The thickness of the side protective layer is 3n The thickness of the non-reflective surface side protective layer is set to 100 nm to 1000 nm, and the non-reflective surface side protective layer is formed of indium in ITO as indium oxide (InO). Reflector for lighting equipment.

  According to the present invention, discoloration of the silver film can be suppressed.

Sectional drawing which shows the lighting plate for lighting fixtures of embodiment which concerns on this invention Graph showing the transmission spectrum of ITO film formed without introducing oxygen into the layer Table showing results of weather resistance test of Examples and Comparative Examples Sectional view showing a conventional reflector Diagram explaining the discoloration mechanism of silver Graph showing the UV intensity characteristics of fluorescent lamps The figure which shows the lighting fixture which has a silver vapor deposition reflector The figure which shows the film thickness by the position of silver Graph showing film thickness dependence of silver film transmission spectrum

  Hereinafter, the reflector for lighting fixtures of embodiment which concerns on this invention is demonstrated with reference to drawings. FIG. 1 shows a reflector 10 for a lighting fixture according to an embodiment. In the reflecting plate 10, a layer that cuts a wavelength of 400 nm or less, that is, a non-reflecting surface side protective layer 13 is formed as a UV cut layer between the undercoat layer 12 and the silver film 14 that is a reflecting layer. By this, UV which permeate | transmits the silver film 14, especially the wavelength of 320 nm vicinity is cut, and the base material 11 and the undercoat layer 12 are protected. Thereby, discoloration of the silver film 14 can be suppressed.

  That is, the reflector 10 includes a base material 11, an undercoat layer 12, a non-reflective surface side protective layer 13, a silver film 14, a reflective surface side protective layer 15, and a top coat layer 16, and these components are the above-mentioned components. Are stacked from the lower layer to the upper layer.

  The substrate 11 is made of metal, alloy such as aluminum, iron, magnesium, zinc, PBT (polybutylene terephthalate), PET (polyethylene terephthalate), PC (polycarbonate), PMMA (polymethyl methacrylate), PPS (polyphenylene sulfide). , SPS (syndiotactic polystyrene), PPO (polyphenylene oxide), PEI (polyetherimide), or other plastics. The base material 11 can be molded by a known molding method depending on the material and the shape of the reflective material. However, the surface is preferably as smooth and clean as possible. Further, it is desirable to remove the mold release agent, gas mark, lubricant, oil, and the like adhering during molding by physical means.

  The undercoat layer 12 is formed for the purpose of improving the adhesion between the base material 11 and the non-reflective surface side protective layer 13 and improving the smoothness of the base material 11. If the adhesiveness and smoothness between the base material 11 and the non-reflective surface side protective layer 13 are sufficiently secured, the undercoat layer 12 can be omitted. For the undercoat layer 12, a known coating film made of acrylic resin, silicone resin, fluororesin, epoxy resin, melamine resin, or the like can be used. As the coating method, a known coating method such as spray coating, spin coating, roll coating, dip coating or the like can be applied. Moreover, well-known means, such as a heat | fever, UV, an electron beam, can be used for the hardening method.

The non-reflective surface side protective layer 13 is made of ITO. The formation method may be a sputtering method, a physical method such as a vacuum deposition method, or a chemical means such as a spray method or a CVD method. In general, when ITO film is formed, sputtering is performed in a gas atmosphere containing oxygen to form transparent In ₂ O _3. However, in the non-reflecting surface side protective layer 13, oxygen gas is not introduced and UV is introduced. InO having high cutting performance is formed.

  FIG. 2 shows a transmission spectrum of the ITO film formed without introducing oxygen. As a result of analyzing the composition by X-ray photoelectron spectroscopy (XPS), the element ratio of In (indium): O (oxygen): Sn (tin) is approximately 10: 10: 1, and In is formed as almost InO. It can be confirmed that a small amount of tin oxide is doped.

  The ITO film of the non-reflective surface side protective layer 13 has a film thickness of about 100 to 1000 nm, more preferably about 500 to 1000 nm in order to sufficiently cut UV having a wavelength of 400 nm or less. The non-reflective surface side protective layer 13 is disposed on the opposite side of the reflective surface 14 </ b> A of the silver film 14.

  The silver film 14 is formed by forming silver or an alloy mainly composed of silver with a film thickness of about 20 to 1000 nm. The formation method may be a PVD method such as a sputtering method, a vacuum deposition method, or an ion plating method, or may be a chemical precipitation method such as a silver mirror reaction.

  Further, if silver or an alloy mainly composed of silver is laminated on the outermost layer with a thickness of 20 nm or more, the composition on the substrate side is a metal other than silver, for example, aluminum, for the purpose of improving heat resistance and adhesion. In addition, other elements such as copper and nickel may be contained.

The reflecting surface side protective layer _15, it is possible to use _{ITO, In 2 O 3, SnO} 2, a transparent oxide such as ZnO. Among them, when a sputtering apparatus is used, it is preferable in terms of manufacturing to form ITO with the same material as the non-reflective surface side protective layer 13 with a film thickness of 3 to 30 nm, which is easy to sputter and has high transparency. . In order to achieve both long-term weather resistance, gas barrier properties and transparency, a film thickness of 7 to 15 nm is more preferable.

  Further, in order to ensure transparency, the reflective surface side protective layer 15 is formed thinner than the non-reflective surface side protective layer 13. Although the oxidation degree of ITO does not matter, it is preferable to form the film without introducing oxygen gas into the sputter layer in order to prevent discoloration due to oxidation of the silver film 14 during the formation of the reflective surface side protective layer 15.

  The top coat layer 16 is formed for the purpose of protecting the silver film 14 and the thin reflective surface side protective layer 15, and a known coating film made of an acrylic resin, a silicone resin, a fluororesin, an epoxy resin, a melamine resin or the like is used. The coating method is selected from known methods such as spray coating, spin coating, roll coating and dip coating. As a curing method, known means such as heat, UV, and electron beam can be used.

  Next, the operation of the lighting instrument reflector 10 will be described. When light including a wavelength of 400 nm or less is emitted from a light beam, the UV transmitted through the silver film 14 is cut by the non-reflecting surface side protective layer 13. Visible light is reflected by the surface of the silver film 14. Therefore, there is no UV that passes through the silver film 14 and reaches the undercoat layer 12 and the base material 11, and deterioration of the undercoat layer 12 and the base material 11 can be prevented and light resistance can be improved. Thereby, no discoloration occurs in the silver film 14, and the silver film 14 is protected from discoloration for a long time.

Example 1
(Production of reflectors for lighting fixtures)
Base material: A flat plate made of aluminum was wiped off with absorbent cotton soaked with 2-propanol to form a clean surface base material.
Undercoat layer: An epoxy-modified acrylic melamine paint (manufactured by Takashi Kubo Paint Co., Ltd.) was dried and then spray-coated to a film thickness of 5 μm, and then baked and dried at 140 ° C. for 30 minutes.

  Non-reflective surface side protective layer: An ITO target doped with 5% tin was used and formed with a thickness of 500 nm by a DC magnetron sputtering method. During film formation, the oxygen partial pressure was set to 2 × 10 −2 Pa.

  Silver film: A silver film having a thickness of 100 nm was formed by a DC magnetron sputtering method using a target made of 99.9% pure silver.

  Reflective surface side protective layer: An ITO target doped with 5% tin was used and formed to a thickness of 10 nm by DC magnetron sputtering. During film formation, oxygen was not introduced into the sputtered layer.

  Top coat layer: After the acrylic melamine paint (manufactured by Takashi Kubo Paint Co., Ltd.) was dried and spray-coated so that the film thickness became 5 μm, it was formed by baking and drying at 160 ° C. for 40 minutes.

(Example 2)
When forming the non-reflective surface-side protective layer, oxygen was not introduced into the sputtering layer, and an ITO film having a thickness of 500 nm was formed. Otherwise, a reflector for a lighting fixture was produced under the same conditions as in Example 1.

(Comparative Example 1)
A reflective plate for a lighting fixture was produced under the same conditions as in Example 2 except that the thickness of the non-reflective surface-side protective layer was 5 nm.

(Comparative Example 2)
In the same manner as in Examples 1 and 2, a reflector for a lighting fixture in which a non-reflective surface side protective layer was not formed was produced.

(Evaluation method)
Light reflectance: The total light reflectance at a wavelength of 555 nm was measured using a self-recording spectrophotometer for the reflector for lighting equipment obtained as described above.
Weather resistance: The obtained reflecting mirror was irradiated with a mercury lamp for 120 days with a UV intensity of 2 mW / cm 2 in a constant temperature layer at 120 ° C. Then, the total light reflectance in wavelength 555nm was measured using the self-recording spectrophotometer. Moreover, the tracing paper was put on the sample and the appearance was observed.

FIG. 3 shows the evaluation results. As can be seen from FIG. 3, in Examples 1 and 2, no discoloration occurred in the silver film, and the effect of the present invention was recognized.
In Comparative Examples 1 and 2, brown discoloration was observed.

  The reflector 10 for lighting fixtures of this embodiment can suppress UV degradation of the undercoat layer 12 and the base material 11, and can improve light resistance. Thereby, it can suppress that the silver film 14 discolors.

  Further, the reflective surface side protective layer 15 and the non-reflective surface side protective layer 13 which are the upper and lower ITO films of the silver film 14 not only improve the heat resistance and moisture resistance, but also the non-reflective layer which is the lower layer of the silver film 14. By increasing the thickness of the ITO film of the surface-side protective layer 13, the UV cut performance is enhanced, the deterioration of the undercoat layer 12 and the base material 11 is suppressed, and the light resistance of the reflector for a lighting fixture can be improved.

  Further, light resistance can be further improved by forming indium as InO in the ITO film of the non-reflective surface side protective layer 13 which is the lower layer of the silver film 14.

DESCRIPTION OF SYMBOLS 10 Reflector for lighting fixtures 11 Base material 13 Non-reflective surface side protective layer 14 Silver film 15 Reflective surface side protective layer

Claims (1)

A substrate;
A reflective layer that has a reflective surface that reflects visible light that includes silver and that has a thickness at which a window of transmittance having a peak at a wavelength of 320 nm may be formed;
A reflective surface side protective layer disposed on the reflective surface side of the reflective layer and having weather resistance and gas barrier properties;
By disposing the reflective layer on the opposite side of the reflective surface and making it thicker than the reflective surface-side protective layer, light having a wavelength of 400 nm or less is cut to suppress deterioration of the substrate. A non-reflective surface side protective layer;
Have
The non-reflective surface side protective layer and the reflective surface side protective layer are both indium tin oxide (ITO),
The thickness of the reflective layer is set to 20nm~1000nm Rutotomoni, the reflective layer has a thickness comprises at least the following parts 170 nm,
The thickness of the reflective surface side protective layer is set to 3 nm to 30 nm,
The film thickness of the non-reflective surface side protective layer is set to 100 nm to 1000 nm,
And the said non-reflective surface side protective layer is a reflecting plate for lighting fixtures in which indium in ITO is formed as an indium oxide (InO).

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