KR100257098B1 - Color mirrors and the method for the preparation thereof - Google Patents

Abstract

PURPOSE: A color mirror, which shows more clear and various colors without additional protective coating thereof and does not emit environment contaminating materials, and a method for preparing thereof are provided. CONSTITUTION: The color mirror comprises a base plate, a semitransparent film, a transparent film and a reflective film, where the semitransparent film has a thickness of 2-20 nanometer and is made of Cr, Nd, Zr or stainless steel or an alloy thereof. The color mirror is prepared by coating the one side of the base plate with the semitransparent film, the transparent film and the reflective film in sequence by using a sputtering method.

Description

Color mirror showing various colors and manufacturing method thereof

The present invention relates to a coating having various colors by forming a multilayer film on a transparent substrate by using a vacuum deposition technique, and more particularly, to a semi-transparent thin film, transparent film on one surface of the substrate in a vacuum By sequentially coating a light reflecting film, the present invention relates to a color mirror showing various and vivid colors due to interference of light and a manufacturing method thereof.

The classical technique of making a mirror is to make a mirror by coating the back side of the transparent glass by a silver mirror reaction. However, recently, due to pollution problems, it has begun to be replaced by a mirror made of aluminum. An aluminum mirror heats aluminum in a vacuum and finely coats the vapor generated on the glass surface to form a reflective surface to produce a mirror. Since the mirror produced by the above method is not as durable as a conventional mirror by a silver mirror reaction, the mirror is used after the protective coating. Aluminum mirrors do not show color because they were developed to replace mirrors by simply silver mirror reactions.

In addition, as a method for enhancing the durability of the aluminum mirror, mirrors using chromium (Cr) metal and titanium (Ti) instead of aluminum have been developed, but these mirrors do not all exhibit color.

On the other hand, the reflectance of the mirror is determined according to the type of material used, the reflectivity of the mirror using aluminum is about 90%, when using titanium is about 60%. If stainless steel is used, the reflectance is slightly lower than this. In order to control the reflectance, an alloy of the above-mentioned metals may be used, but in no case exhibits color.

In addition, with the development of the vacuum technology, a thin reflective film was formed on the glass surface by using a vacuum deposition technique such as sputtering method, and a color mirror was developed using the interference phenomenon of light. The type of colors that can be displayed is greatly limited.

As a method of coating the mirror so that the color appears, a blue mirror using a light interference phenomenon has been developed and used. As a representative method, a blue mirror for automobiles manufactured by Shott, Germany may be used. This mirror uses a wet (sol-gel) method to coat a layer that reflects a particularly large amount of blue on the glass surface and a black protective coating on the back. The mirror achieves this by coating a TiO ₂ layer on glass to a uniform thickness, causing light to interfere. The mirror made in this way is entirely transparent because the TiO ₂ layer is a transparent material, and in order to use it as a mirror, a black protective coating must be applied so that the back side cannot be seen. This process becomes a blue color mirror, but due to the protective coating, the purity of the color is not high, and also has a disadvantage that can be used only by a separate protective coating. In addition, from the viewpoint of a layer serving to reflect light, the overall reflectance of the structure is lower than that of a metal reflecting layer such as chromium (Cr) since only reflection due to optical interference of TiO ₂ occurs. There is also a problem.

As another method of manufacturing a color mirror, the BOC group of the United States has developed a blue mirror that does not require a back coating by coating TiO ₂ on a chromium (Cr) layer using a vacuum coating method. This blue mirror is divided into two types: a back mirror (a mirror having a color layer on the back side of two surfaces of the glass) and a surface mirror (mirror having a color layer on the front surface of the glass). Of these two products, the surface mirror has a disadvantage that the coating film is easily damaged by a relatively small external force because the reflective film is coated on the outer surface (front side) of the transparent substrate. There was a changing problem.

In addition, the mirrors of the above method exhibit blue color using the optical interference phenomenon of the TiO ₂ layer, and therefore, when used as a surface mirror, air (refractive index = 1.0) and TiO ₂ (refractive index = 2.2 to 2.5) are used. Since the difference in refractive index between?) Is about 1.2 to 1.5, color mirrors with a certain degree of purity can be obtained. However, in the case of manufacturing with a back mirror, it is in contact with glass or plastic (refractive index = 1.5), not an air layer, and the difference in refractive index at this time is as low as 0.7-1.0. Thus, the resulting color mirror is not a bright color but a light color.

On the other hand, in addition to the blue as described above, a method of manufacturing a color mirror showing a yellow, a method of producing a mirror by heat-treating the glass coated with silver (Ag) at a high temperature to be colored in yellow, then coating the silver with a reflective film Also developed, but this method only allows the manufacture of mirrors that display a yellow color.

Mirrors exhibiting a color other than blue and yellow are conventionally applied to a method of expressing a color by attaching a second material using a common dye or pigment to the back of the glass and coating silver with a reflective film thereon, or colored glass exhibiting a predetermined color. The method of manufacturing the color mirror which shows a color by forming the reflecting film by this is used.

However, the method of attaching a material showing color to the glass as described above has to go through a multi-step process, there is a disadvantage that the durability of the coloring material is not good. In addition, the method of using the color glass has a disadvantage that the type of color that can be represented is very limited because the type of color glass that is conventionally produced.

The present invention has a more diverse and vivid color as compared to the conventional color mirror as described above, easy to manufacture, can be used even without a separate back protective coating provides a color mirror that does not emit environmental pollutants and its manufacturing method Its purpose is to.

1 is a schematic cross-sectional view showing the layer structure of the color mirror according to the present invention.

2 is a graph showing the spectral reflectance of the blue, yellow and purple mirror glass prepared according to the present invention.

In order to achieve the object as described above, the present invention provides a color mirror formed by sequentially forming a translucent film, a transparent film and a reflective film on one surface of the substrate.

Further, according to another embodiment of the present invention, there is provided a method for producing a color mirror, characterized by sequentially coating a translucent film, a transparent film and a reflective film on one surface of a substrate using a sputtering method.

The present invention is different from the conventional blue mirror of shott and the blue mirror of the BOC group by the fact that a semitransparent film is additionally introduced between the substrate and the reflective film. More specifically, in the present invention, a semi-transparent film and a transparent film are further introduced between the substrate and the reflective film to improve color purity. The semi-transparent film introduced in the present invention is a layer that blocks only a part of the transmitted light, and may be obtained by thinly coating a material such as metal itself or nitride, carbide, etc. of the metal on a substrate. For example, the metals shown in Table 1 below, nitrides or carbides thereof can be used. Translucent films formed of such materials have a high color refractive index (complex refractive index including absorption of light) compared to the refractive index of the conventional transparent thin film, thereby obtaining a clear color. Therefore, in the conventional blue mirror, TiO ₂ having a high refractive index is mainly used as a reflective film to show a high refractive index difference. However, since the light absorbing layer having a high refractive index is already used in the present invention, the material used for the reflective film has a high refractive index. You don't have to. In fact, all of the conventional metal thin films such as Tables 1a to 1c can be used, and the optical thickness is adjusted according to the type of material used.

TABLE 1a

TABLE 1b

TABLE 1c

Meanwhile, as the material of the transparent film introduced in the present invention, any oxide may be used as long as it is a material capable of forming a transparent transparent film in the visible region, in addition to the oxides shown in the above table, but all of the metal materials themselves have a high absorption of light. Therefore, it cannot be used as a transparent film.

On the other hand, the semi-transparent film in the present invention may be used alone or an alloy of two or more materials selected from the group consisting of Cr, Ti stainless steel (abbreviated herein as "SST"), Nb and Zr. In addition, a nitride of one material selected from the group consisting of Al, Cr, Sn, Ti, SST, Nb and Zr may be used alone, or a nitride of an alloy of two or more materials may be used.

In addition, in the present invention, the transparent film may use an oxide of one material selected from the group consisting of Sn, Al, Si, Ti, Zr, Nb, and Zn alone or an oxide of an alloy of two or more materials. It is also possible to use nitrides of one material alone or nitrides of alloys of two materials selected from the group consisting of Al and Si.

Meanwhile, as the reflective film, one material selected from the group consisting of Cr, Ti, Al, Si, SST, Zr, Nb, Cu, Ag, and Ni may be used alone or an alloy of two or more materials may be used.

The thickness of the translucent film is preferably in the range shown in the above table, depending on the type of material used, and usually 2 to 20 nm is preferable.

In addition to glass, materials such as plastic (for example, acrylic, polycarbonate, etc.), film (for example, PET film, vinyl, etc.) may be used as the transparent substrate, and the present invention may be made using jewelry or toys as a substrate. It is also possible to apply.

In the present invention, there are various colors depending on the thickness of the transparent film and the kind of the material constituting the same, and the thickness and the material of the transparent coating layer showing typical colors are shown in Table 2 below.

TABLE 2

In the present invention, as shown in the above table, by adjusting and selecting the material and thickness of the transparent coating appropriately, a mirror of various colors can be produced, and in the case of using chromium, tin oxide or the like having excellent chemical resistance as the material of the coating layer, It is possible to make a mirror without applying a separate back protective coating.

In addition, by introducing a translucent film layer, it is possible to obtain a back coating mirror of high purity, vivid color and various colors. When the back mirror is made by the prior art, it is difficult to obtain a vivid color compared to the surface mirror. This is because when the rear mirror is made, the difference in optical refractive index is smaller than that of the surface mirror. In the present invention, a thin light absorbing layer is used, and since a high refractive index of most light absorbing materials is used, vivid colors can be obtained. Therefore, the refractive index of the transparent dielectric layer used previously is not so important in the present invention. That is, in the prior art, the color of the transparent dielectric layer has a usable level only when the refractive index is 2.3 or more, but in the present invention, a vivid color may be obtained using any material having a refractive index of 1.5 or more. In addition, since all materials having a refractive index of 2.3 or more are significantly slower in coating speed, the present invention can produce color mirrors that exhibit more vivid colors than existing products while using materials having a high coating speed.

The color mirror according to the present invention can be used for building or decoration.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, these examples are provided only to make the present invention easier to understand, and the scope of the present invention is not limited to these examples.

Example 1

On a clear float glass substrate having a thickness of 6 mm, chromium (Cr), tin oxide (SnO ₂ ), and aluminum (Al) are shown in FIG. 1 under the conditions as shown in Table 3 below. As described above, a translucent film, a transparent film, and a reflective film were sequentially formed to form a multilayer thin film layer so as to have a thickness of 12 nm, 110 nm, and 30 nm, respectively. The color appeared at this time was vivid blue. As a film forming apparatus, a continuous in-line magnetron sputtering method was used.

EXAMPLE 2 AND 3

The treatment was carried out in the same manner as in Example 1 except that the treatment conditions for forming the SnO ₂ layer for forming the transparent film layer were changed as shown in Table 3 below, so that the thickness was 160 nm and 205 nm, respectively. Color mirrors of yellow (Example 2) and purple (Example 3) were prepared. The spectral reflectance of the mirrors manufactured by the above example was measured, and the results are shown graphically in FIG. 2.

TABLE 3

[Examples 4 and 5]

A color mirror was produced in the same manner as in Example 1 except that the materials used for forming the translucent film, the transparent film, and the reflective film were changed as shown in Table 4 below. The thickness of each layer formed by the said Example was 9 nm, 152 nm, 95 nm, and 9 nm, 138 nm, and 95 nm, respectively.

TABLE 4

EXAMPLES 6 AND 7

A color mirror was produced in the same manner as in Example 1 except that the materials used for forming the translucent film, the transparent film, and the reflective film were changed as shown in Table 5 below. The thickness of each layer formed by the said Example was 6 nm, 147 nm, 45 nm, and 7 nm, 183 nm, and 56 nm, respectively. Advantages of this embodiment, since a stainless steel target is used a lot in the existing sputtering apparatus, since the equipment for producing the reflective glass for building is usually equipped with a stainless steel target, it is not necessary to install a separate target as it is used Color mirror of the invention can be produced and there is an advantage that can easily change the variety.

TABLE 5

Example 8

Treated in the same manner as in Example 1 except that chromium nitride, silicon nitride, and titanium were used as materials for forming the translucent film, the transparent film, and the reflective film, respectively, and the treatment conditions were changed as shown in Table 6 below. To produce a color mirror. The thickness of each layer formed by the said Example was 2 nm, 120 nm, and 40 nm, respectively.

In Examples 1 to 7, the layer structure such as substrate / nitride / oxide / metal or substrate / metal / oxide / metal is used. A coating chamber is required to pass the device once (ie in one pass) to coat all layers. However, in this embodiment, by using chromium nitride and silicon nitride as the material of the translucent film and the transparent film, these two layers can be coated in one chamber. In this way, the color mirror of the present invention can be produced by a small coating apparatus having only two chambers.

TABLE 6

Example 9

As the material used for forming the translucent film, the transparent film and the reflective film, chromium nitride, oxides of zinc / tin alloy (70/30% by weight) and aluminum are used, except that the treatment conditions are changed as shown in Table 7 below. And the same process as in Example 1 to prepare a color mirror. The thickness of each layer formed by the said Example was 5 nm, 126 nm, and 49 nm, respectively.

The oxide of the Zn / Sn alloy used in the above embodiment can be produced at a high speed because of superior chemical durability and higher applied power than when using Zn alone, and targets compared to using Sn alone. The advantage is that the material is cheap.

TABLE 7

According to the present invention, by introducing a semi-transparent film having a high reflectance and a high refractive index between the substrate and the reflecting film, color mirrors that are more vivid and show various colors can be manufactured without a separate back protective coating, and thus, environmental pollutants can be produced. It is possible to provide a color mirror that does not emit.

Claims (8)

Translucent, transparent and reflective films are sequentially formed on one surface of the substrate, and the translucent film has a thickness of 2 to 20 nm, and is made of an alloy consisting of Cr, Nb, Zr, stainless steel alone, or two or more materials. Color mirror made with. The color mirror according to claim 1, wherein the transparent film is made of an oxide of an alloy composed of two or more of Sn, Nb, and Zn. The color mirror of claim 1, wherein the reflective film is made of an alloy consisting of one or more of Cr, Ti, Si, stainless steel, Zr, Nb, Cu, and Ni. The method of manufacturing a color mirror according to claim 11, wherein the semi-transparent film, the transparent film and the reflective film are sequentially coated on one surface of the substrate using a sputtering method. A semitransparent film, a transparent film, and a reflective film are sequentially formed on one surface of the substrate, and the translucent film has a thickness of 2 to 20 nm and consists of a nitride of an alloy composed of Cr, Nb, Zr, stainless steel alone, or two or more materials. Color mirror characterized in that. The color mirror according to claim 5, wherein the transparent film is made of an oxide of an alloy composed of two or more of Sn, Nb, and Zn. The color mirror according to claim 5, wherein the reflective film is made of an alloy composed of one or more of Cr, Ti, Si, stainless steel, Zr, Nb, Cu, and Ni. A method of manufacturing a color mirror according to claim 15, wherein the semi-transparent film, the transparent film and the reflective film are sequentially coated on one surface of the substrate using a sputtering method.

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