JP4857205B2 - Shade - Google Patents

Description

  The present invention relates to a light-shielding body made of an MgO film that has a light transmittance that is reduced when it receives light including ultraviolet light in a specific wavelength range, for example, sunlight, before receiving the light.

  The light shield is attached to the boundary of the room to block direct sunlight from entering indoors, to prevent peeping indoors, and to prevent other people from seeing diagonally from the display of electronic devices such as personal computers and mobile phones. Used to prevent peeping.

2. Description of the Related Art Conventionally, there has been disclosed a dimming type light shielding body that adjusts daylighting indoors by being attached to a window surface into which sunlight enters, such as a blind, a roll screen, and a curtain (for example, Patent Document 1).
JP-A-11-193678 (Claims 1 and 2)

  However, the dimming type light-shielding body described in Patent Document 1 includes an opening / closing mechanism that opens and closes the opening / closing mechanism and a control unit that controls the operation of the opening / closing mechanism. In this control means, when it is determined that there is direct light, the light intensity of the specific wavelength is further detected by the detection means, and if the light intensity of the specific wavelength is equal to or higher than a preset value, the light control type light shielding A filter that allows only light of a specific wavelength to pass through because the body is closed and the open / close mechanism is controlled to open the dimming light shield when the intensity of light of a specific wavelength is below a preset value. In addition, as a light-blocking body used for general houses and vehicles, such as a sensor member that detects the intensity of light transmitted through the filter, the apparatus is complicated and the process until the light is blocked is complicated.

  An object of the present invention is to provide a light-shielding body that is suitable for applications such as rear glass of automobiles in which light transmittance is reduced when receiving light including ultraviolet rays in a specific wavelength range compared to before receiving the light. There is to do.

  Another object of the present invention is to receive light containing ultraviolet rays in a specific wavelength region, and after the light transmittance is reduced, it is almost recovered to the transmittance before receiving the light containing ultraviolet rays in the specific wavelength region by heating. An object of the present invention is to provide a light-shielding body suitable for applications such as automobile rear glass.

In the invention according to claim 1, an MgO film having a thickness of 0.2 to 500 μm and a purity of 99.0% or more is formed on a transparent substrate, and the MgO film has a thickness of 0.1 to 10 μm and a wavelength. A group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn , coated with a protective film that transmits ultraviolet light of 280 to 380 nm, the concentration of C in the MgO film being less than 2000 ppm Light containing ultraviolet rays having a wavelength of 280 to 380 nm , wherein the concentration of one or more selected transition metal elements is 2000 ppm or less, and the concentration of each of the transition metal elements is 500 ppm or less. When received, the light-shielding body is characterized in that the light transmittance is reduced by 0.5% or more compared to before receiving this light.
The invention according to claim 2 is the invention according to claim 1, and is a light-shielding body used for a rear glass of an automobile.

The invention according to claim 3 is the light-shielding body according to claim 1 or 2 , wherein a heating wire is wired inside the transparent substrate.

According to the light shielding body of the present invention, is formed purity 99.0% or more of the MgO film having a thickness of 0.2~500μm on a transparent substrate, MgO film, 0.1 to 10 [mu] m thick met In the MgO film, the concentration of C is less than 2000 ppm, and Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn. the concentration of one or more transition metal elements selected from the group consisting is at 2000ppm or less, and the concentration of 500ppm or less der Rukoto of each element of the transition metal element, the ultraviolet rays having a wavelength of 280~380nm When it contains light, the light transmittance can be reduced by 0.5% or more compared to before receiving the light.

  Moreover, according to another light-shielding body according to the present invention, the MgO film whose light transmittance has been reduced by receiving light containing ultraviolet rays having a wavelength of 280 to 380 nm is heated by a heating wire wired inside the transparent substrate. Thus, the original transmittance can be almost recovered again.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a diagram schematically illustrating a light shielding body according to the present invention. As shown in FIG. 1, in the light shielding body according to the present invention, an MgO film 12 having a thickness of 0.2 to 500 μm and having a purity of 99.0% or more is formed on a transparent substrate 13, and the MgO film 12 is thick. It is covered with a protective film 11 of 0.1 to 10 μm. Further, the MgO film 12 has a C concentration of less than 2000 ppm, and one or two selected from the group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn. The concentration of the above transition metal element is 2000 ppm or less, and the concentration of each element of the transition metal element is 500 ppm or less. In the present specification, the purity of the MgO film and the concentration of each element are represented by values measured at the time of the MgO powder before film formation.

  The thickness of the transparent substrate 13 is not particularly limited, but is preferably 1 to 10 mm. If it is less than 1 mm, the strength is not sufficient, and if it exceeds 10 mm, the light transmittance tends to decrease. The material of the transparent substrate 13 is not particularly limited as long as it is a transparent body. For example, glass, plastic, ceramics, etc. are mentioned.

  The reason why the purity of the MgO film 12 is 99.0% or more is that if it is less than 99.0%, the transparency of the MgO film 12 cannot be obtained due to impurities. This is because there is no change. Among these, the purity of the MgO film 12 is preferably 99.5% or more. Also, the thickness of the MgO film 12 is set to 0.2 to 500 μm because the film thickness is too thin below the lower limit, so that it is sufficient to receive light including ultraviolet rays in the wavelength range of 280 to 380 nm, such as sunlight. This is because there is no light shielding effect, and when the value exceeds the upper limit, the transmittance before receiving the light becomes too low and sufficient transparency cannot be obtained. The thickness of the MgO film 12 is preferably 1 to 100 μm.

The MgO film 12 easily reacts with water and carbon dioxide, and easily deforms and deteriorates when used outdoors. Therefore, in order to prevent these, it is covered with a protective film 11 having weather resistance. The reason why the thickness of the protective film 11 is 0.1 to 10 μm is that the weather resistance is insufficient if it is less than the lower limit, and the film is liable to be cracked or peeled if the upper limit is exceeded. The thickness of the protective film 11 is preferably 0.2 to 3 μm. This protective film 11 has a property of transmitting ultraviolet rays including a wavelength range of 280 to 380 nm. For example, a SiO ₂ film and a SiON film are preferable.

  The MgO film 12 in the light-shielding body according to the present invention exhibits a white to purple color when receiving an ultraviolet ray including a wavelength range of 280 to 380 nm, and the MgO film 12 exhibiting this purple color is visible at 380 to 780 nm. By absorbing light in the light region, the transmittance of light in the visible light region can be lowered. The technical reason why the MgO film 12 absorbs ultraviolet rays including a wavelength range of 280 to 380 nm and exhibits a purple color from white by receiving the ultraviolet rays has not been elucidated at the present time. This is presumably because the lattice defects are excited by ultraviolet rays. When the thickness of the MgO film 12 after receiving ultraviolet rays is 0.2 to 500 μm, the transmittance in the visible light region is reduced by 0.7 to 30% at maximum, preferably 23 to 30%.

  The MgO film 12 constituting the light shielding body of the present invention is formed on the transparent substrate 13 by a dry method or a wet method. Examples of the dry method include a vacuum evaporation method, an electron beam evaporation method, an ion plating method, and a sputtering method. Examples of the wet method include a spin coating method, a spray coating method, a laminated screen printing method, and a doctor blade method.

  When the MgO film 12 is formed by a vacuum deposition method as a dry method, a pellet MgO deposition material is used as a target material. This MgO vapor deposition material has a MgO purity of 99.0% or more, preferably 99.5% or more. Furthermore, this MgO vapor deposition material has a C concentration of less than 2000 ppm and a transition metal element concentration of 2000 ppm or less. The C concentration and the transition metal element concentration are within the above ranges because when the C concentration is 2000 ppm or more and the transition metal element concentration exceeds 2000 ppm, the lattice defects in the MgO crystal lattice are reduced by the impurities, and thus the ultraviolet rays are received. However, there is no change in color, or sufficient transparency is not obtained in the MgO film before receiving ultraviolet rays, and there is not much change in light transmittance before and after receiving ultraviolet rays. is there. The transition metal element is one or more elements selected from the group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn, and the concentration of each element is 500 ppm or less. . The reason why the concentration of each element is 500 ppm or less is that when 500 ppm is exceeded, lattice defects in the MgO crystal lattice are reduced by impurities, so that no change in color is observed even when receiving ultraviolet rays, or MgO before receiving ultraviolet rays. This is because sufficient transparency of the film cannot be obtained, and there is not much change in the light transmittance before and after receiving the ultraviolet rays.

  The diameter and thickness of the MgO vapor deposition material are not particularly limited, but the diameter is determined from the range of 1 to 20 mm and the thickness is determined from the range of 1 to 30 mm in terms of the film formation speed and the frequency of occurrence of splash. Note that the composition of the MgO vapor deposition material is not limited to polycrystals, and single crystals can be used as long as the above purity conditions are satisfied.

  When the MgO film 12 is formed by a wet method, first, MgO powder is dispersed in alcohol as a solvent to prepare a dispersion. In preparing this dispersion, a dispersant for improving the dispersibility of the MgO powder is appropriately added. Next, a binder and an organic solvent are added to the dispersion and mixed uniformly to obtain an MgO paint.

  The obtained MgO paint is applied onto the transparent substrate 13 by a wet method such as spin coating, spray coating, laminated screen printing, or doctor blade method, and then the transparent substrate 13 is dried and baked to be applied. The MgO film 12 is formed on the transparent substrate 13 by fixing the film.

The MgO film 12 formed on the transparent substrate 13 by a dry method or a wet method is covered with a protective film 11 as shown in FIG. The manufacturing method and coating method of the protective film are as follows. First, tetramethoxysilane is dissolved in ethanol so that the concentration of SiO ₂ is 0.5 to 5.0% by mass, and 0.001 to 0.1% by mass of acid is added as a catalyst. Although it does not specifically limit as an acid to add, It is preferable to use hydrochloric acid, nitric acid, acetic acid, etc. Next, this solution is heated at a temperature of 40 to 80 ° C. for 30 minutes to 10 hours, and then cooled to obtain a protective film forming liquid. The method of coating the protective film forming liquid is not particularly limited, but it is preferable to coat the MgO film 12 using a spin coating method, a spray coating method, a CVD method, or the like. Next, the film is fixed by heating in the atmosphere at a temperature of 150 to 300 ° C. for 10 to 60 minutes, and a SiO ₂ film having a thickness of 0.1 to 10 μm is formed on the surface of the MgO film 12.

  Next, another embodiment of the present invention will be described with reference to FIG. In FIG. 2, the same components as those in the above-described embodiment are denoted by the same reference numerals as those in FIG.

  The light shield in this embodiment includes a heater 14. The heater 14 includes a heating wire 14 a, a power source 14 b, and a switch 14 c connected in series. The heating wire 14 a is wired inside the transparent substrate 13.

  The MgO film 12 after receiving light containing ultraviolet rays having a wavelength in the range of 280 to 380 nm is heated at 100 to 600 ° C., preferably 200 to 300 ° C., by the heating wire 14 a wired inside the transparent substrate 13. From the purple tone to the decolored state, it can be almost recovered to the transmittance before receiving the light. Although the technical reason for returning from the purple tone to the decolored state by heating is not clarified at present, it is assumed that the lattice defects in the MgO crystal lattice are excited by receiving ultraviolet rays. If the heating temperature is less than the lower limit of 100 ° C., a sufficient decoloring effect cannot be obtained, and thus the transmittance does not sufficiently recover. Even if the heating temperature exceeds the upper limit of 600 ° C., the decoloring effect does not change and the transmittance is maintained. Since no change is observed, heating above 600 ° C. is a waste of heat energy.

Further, the protective film 11 in this embodiment has a property of transmitting ultraviolet rays including a wavelength range of 280 to 380 nm as described above, and the heating wire 14a is not deformed or deteriorated by the heat of the heating wire 14a. Heat resistance above the heating temperature. For example, a SiO ₂ film and a SiON film are preferable.

  Next, examples of the present invention will be described in detail together with comparative examples.

<Example 1>
Previously not a a M gO purity 99.9%, C concentration 50 ppm, as a transition metal element, Fe, and 10ppm Mn and Zn, respectively, a MgO powder containing 20ppm of Si, is dispersed in an alcohol as a solvent dispersion A liquid was prepared. A dispersant for improving the dispersibility of the MgO powder was appropriately added to this dispersion. A mixed solution in which polyester as a binder and alcohol as an organic solvent were added to this dispersion was stirred with a magnetic stirrer to obtain a MgO paint. As a transparent substrate, a glass substrate having a thickness of 3 mm was prepared. Next, after applying the MgO paint on the glass substrate by the doctor blade method, the transparent substrate 13 is dried, fired at 150 ° C. to fix the coating film, and the coating is fixed. A 100 μm thick MgO film was formed. Next, 0.005% by mass of nitric acid as a catalyst was added to a solution in which tetramethoxysilane was dissolved in ethanol so that the concentration of SiO ₂ was 1% by mass. This solution was heated at 60 ° C. for 60 minutes and then cooled to prepare a protective film forming solution. Next, this protective film-forming solution is applied onto the MgO film by using a spin coating method, and then heated in the air at a temperature of 200 ° C. for 30 minutes to form a 0.5 μm thick SiO 2 film on the surface of the MgO film. _Two films were formed, and the light shielding body of the present invention shown in Table 1 below was formed.

<Example 2>
As shown in Table 1 below, Example 1 was used except that a glass substrate having a thickness of 3 mm was used as the transparent substrate, the thickness of the MgO film was 250 μm, and the thickness of the protective film was 0.5 μm. The light shielding body of the present invention was formed under the same conditions.

<Example 3>
As shown in Table 1 below, Example 1 was used except that a glass substrate having a thickness of 3 mm was used as the transparent substrate, the thickness of the MgO film was 400 μm, and the thickness of the protective film was 0.5 μm. The light shielding body of the present invention was formed under the same conditions.

<Example 4>
The light-shielding body of the present invention was used under the same conditions as in Example 1 except that a glass substrate having a thickness of 3 mm was used as the transparent substrate, the thickness of the MgO film was 500 μm, and the thickness of the protective film was 0.5 μm. Formed.

<Example 5>
The light-shielding material of the present invention was used under the same conditions as in Example 1, except that a glass substrate having a thickness of 3 mm was used as the transparent substrate, the thickness of the MgO film was 0.8 μm, and the thickness of the protective film was 0.5 μm. Formed body.

<Comparative Example 1>
As shown in Table 1 below, a light-shielding body was formed under the same conditions as in Example 1 except that the thickness of the MgO film was 0.1 μm.

<Comparative example 2>
As shown in Table 1 below, a light shield was formed under the same conditions as in Example 1 except that the thickness of the MgO film was 2000 μm.

<Comparative Example 3>
The light-shielding body shown in Table 1 below was formed under the same conditions as in Example 1 except that the MgO film was formed using an MgO vapor deposition material having a purity of less than 99.0% and a purity of 98.5%.

＜比較試験及び評価１＞
特定波長域の紫外線を含む光として模擬的に高圧水銀ランプ（波長２００〜６００ｎｍ：ウシオ電機社製）を用いて、このランプの光を実施例１〜５及び比較例１〜３で形成した遮光体に照射した。これら遮光体の可視光透過率を分光光度計（日立製作所社製：Ｕ−４０００）を用いて測定した。測定は紫外線を照射する前と照射した後行った。上記高圧水銀ランプの照射条件は照射強度８６ｍＷ／ｃｍ²及び照射量５００ｍＪ／ｃｍ²であった。その結果を表２に示す。

<Comparison test and evaluation 1>
Using a high-pressure mercury lamp (wavelength 200 to 600 nm: manufactured by Ushio Inc.) as light containing ultraviolet rays in a specific wavelength range, the light from this lamp was formed in Examples 1-5 and Comparative Examples 1-3. The body was irradiated. The visible light transmittance of these light shielding bodies was measured using a spectrophotometer (manufactured by Hitachi, Ltd .: U-4000). Measurement was performed before and after irradiation with ultraviolet rays. The irradiation conditions of the high pressure mercury lamp were an irradiation intensity of 86 mW / cm ² and an irradiation amount of 500 mJ / cm ² . The results are shown in Table 2.

表２から明らかなように、ＭｇＯ膜の膜厚が０．２μｍ未満である比較例１では紫外線の照射前後において、可視光透過率にほとんど変化はみられなかった。またＭｇＯ膜の膜厚が５００μｍを越える比較例２では、紫外線照射前の透過率が低くなりすぎ十分な透明性が得られなかった。これに対し、実施例１〜５では紫外線照射後の可視光透過率が、紫外線照射前の透過率に比べ０．７〜３０％下がっており、ＭｇＯ膜の膜厚を１００〜５００μｍにすることが効果的であることが確認された。またＭｇＯ膜の純度が９９．０％未満が比較例３では、紫外線の照射前後において、可視光透過率にほとんど変化はみられなかった。このことから、ＭｇＯ膜の純度を９９．０％以上とすることが効果的であることが確認された。

As is clear from Table 2, in Comparative Example 1 in which the thickness of the MgO film was less than 0.2 μm, there was almost no change in the visible light transmittance before and after the ultraviolet irradiation. Further, in Comparative Example 2 in which the film thickness of the MgO film exceeds 500 μm, the transmittance before ultraviolet irradiation becomes too low to obtain sufficient transparency. On the other hand, in Examples 1 to 5, the visible light transmittance after ultraviolet irradiation is 0.7 to 30% lower than the transmittance before ultraviolet irradiation, and the film thickness of the MgO film is set to 100 to 500 μm. Has been confirmed to be effective. In Comparative Example 3, the purity of the MgO film was less than 99.0%, and the visible light transmittance hardly changed before and after the ultraviolet irradiation. From this, it was confirmed that it is effective to set the purity of the MgO film to 99.0% or more.

<Evaluation 2>
The MgO film after ultraviolet irradiation in Example 1 was heated at the temperature and time shown in Table 3 below with a heating wire wired inside the transparent substrate, and then the visible light transmittance was measured.

表３から明らかなように、元の透過率までほぼ回復させるには１００℃以上で１２０分間以上の温度で加熱する必要があることが判った。

As is apparent from Table 3, it was found that it was necessary to heat at 100 ° C. or higher for 120 minutes or longer in order to almost restore the original transmittance.

<Evaluation 3>
First, an MgO film having a film thickness of 100 μm and an initial transmittance of 92.5% was irradiated with ultraviolet rays at an irradiation intensity of 1000 mJ / cm ² and an irradiation amount of 120 mJ / cm ² to reduce the transmittance. Next, the MgO film was heated with a heater at 150 ° C. for 30 minutes to increase the transmittance of the MgO film, and then cooled at room temperature. This process was defined as one cycle, and a reproduction test was performed by repeating this one cycle a plurality of times. The results after 20, 30, and 50 cycles are shown in Table 4 below.

表４から明らかなように、本発明の遮光体では上記工程を５０回以上繰り返してもほぼ元の透過率に戻ることが確認された。

As is apparent from Table 4, it was confirmed that the light shielding body of the present invention returned to the original transmittance almost even when the above process was repeated 50 times or more.

The figure which represented typically the light-shielding body which concerns on this invention. The figure which represented typically the light-shielding body of another embodiment of this invention.

Explanation of symbols

11 Protective film 12 MgO film 13 Substrate 14 Heater

Claims (3)

An MgO film having a thickness of 0.2 to 500 μm and a purity of 99.0% or more is formed on a transparent substrate, and the MgO film transmits ultraviolet rays having a thickness of 0.1 to 10 μm and a wavelength of 280 to 380 nm. Covered with a protective film ,
The concentration of C in the MgO film is less than 2000 ppm, and one or more transition metal elements selected from the group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn are used. The concentration is 2000 ppm or less, and the concentration of each element of the transition metal element is 500 ppm or less,
A light-shielding body characterized in that when light containing ultraviolet rays having a wavelength in the range of 280 to 380 nm is received, the light transmittance is reduced by 0.5% or more compared to before receiving the light. The light-shielding body according to claim 1, which is used for a rear glass of an automobile. Inside the heating wire wiring claims 1 or 2 light-shielding body according of the transparent substrate.

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