KR20090036445A - Menufacturing method for thin film using glancing angle deposition of a deposition material and high reflection coatings method using it - Google Patents

Abstract

A multi-layered thin film manufacturing method and a high reflective coating method using the same are provided to prevent a chamber from being polluted and reduce defective production by removing impurity and fine dust remaining in a thin film. A multi-layered thin film manufacturing method comprises: a step for depositing one kind of material on a substrate; a step for changing a glancing angle by glancing angle deposition; and a step for changing refractive index and manufacturing a thin film deposited over three layers. The multi-layered thin film is coated to have the average reflection rate of 95% or more in an ultraviolet ray region, a visible ray region and wavelength band of the ultraviolet ray region.

Description

TECHNICAL FIELD OF THE INVENTION A method for manufacturing a multilayer thin film using oblique incidence deposition of a material and a method of high reflection coating using the same

The present invention relates to a method for manufacturing a multilayer thin film using a gradient incidence deposition of one kind of material and a high reflection coating method using the same. The present invention relates to a multi-layered thin film having high reflection characteristics in the region and the infrared region, and a high reflection coating used in various reflectors and optical filters using the same.

In general, high reflection coatings are optical thin film coatings for increasing light reflectance from a substrate, whereas anti-reflection coatings are optical thin coatings for increasing light transmittance from a substrate. Background Art [0002] The optical element has been used as a method of increasing the reflection at the interface caused by the difference in refractive index between air and air by using the interference effect of light.

The prior art relates to a method of manufacturing a high reflection mirror, US Pat. No. 6,128,126 discloses a method of manufacturing a mirror having excellent reflectance in a wide wavelength band through a high reflection coating using two or more kinds of materials such as ZnS, Ag, Y3F on the substrate It is.

In addition, a method of manufacturing a thin film having a low refractive index by the inclined incidence deposition and a technique related to the anti-reflective coating using the same is disclosed in Korea Patent Publication No. 10-2007-16570.

Therefore, a multi-layered thin film having high reflection efficiency is prepared by using a single material to have various refractive indices by oblique incidence deposition, and a highly reflective coating method using the same is used to fabricate an optical device such as a high reflection mirror. There is a need to reduce the costs and further improve productivity.

According to the present invention for solving the above problems, by using a single material of the deposition by changing the refractive index of the material by gradient incidence deposition, by producing a multilayer thin film having a high reflection characteristics, anisotropic characteristics due to the gradient incident deposition It is an object of the present invention to provide a multilayer thin film manufacturing method and a highly reflective coating method using the same to have almost isotropic characteristics by using a deposition method with a zigzag structure during oblique incidence deposition in order to minimize the problem.

In order to achieve the above object, the present invention provides a multilayer thin film manufacturing method using gradient incident deposition of one kind of material, wherein the refractive index is changed by varying the gradient incidence angle α by gradient incident deposition. It is a method for producing a multilayer thin film deposited in three or more layers.

In addition, the present inventors high reflection coating method for achieving the above object is achieved by varying the tilt angle of incidence (α) by an oblique incident deposition one type material on the substrate by changing the refractive index, but to provide a multilayer thin film of three or more layers, wherein According to the multilayer thin film deposited by the change of the refractive index is a method of high reflection coating (High Reflection Coatings) to have an average reflectance of 95% or more in the wavelength band of the ultraviolet region, visible region and infrared region.

In the above, the deposition material is a metal oxide having high refractive index characteristics such as TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , HfO ₂ , Nb ₂ O ₅ , Nd ₂ O _3, and a metal oxide having high refractive index characteristics. It is preferable to change the refractive index to lower the refractive index by varying the incidence angle of incidence α during deposition, so as to alternately deposit a layer having a high refractive index and a layer having a low refractive index.

In the above, when the deposition of one kind of material on the substrate alternately inclined incident deposition to increase the density of the thin film having a porous pillar microstructure, the refractive index change and uniform thickness in a fixed state It is preferable to deposit by rotating the film 180 degrees after the first deposition, or to deposit the inclined incidence angle? By the zigzag structure at + α and -α.

In the above, it is preferable to control the optical phase thickness of the thin film deposited by the deposition material to have a quarter wavelength thickness.

In the above method, a metal such as silver (Ag) is coated on the substrate before depositing the one kind of material, and then the refractive index is changed to low by the gradient incidence deposition of the one kind of material to alternate between the refractive index before the change and the lowered refractive index. By depositing at least three or more layers, it is desirable to have an average reflectance of 95% or more in the wavelength bands of the ultraviolet region, the visible region and the infrared region.

In the above, glass is used as the substrate, and the refractive index is changed low by the inclined incident deposition of the one kind of material on the glass substrate to deposit three or more layers alternately with the refractive index before the change and the lower changed refractive index , depending on the reference wavelength. It is desirable to have a specific reflecting color formed in a wavelength band having an average reflectance of 95% or more in a specific wavelength band and having an average reflectance of 95% or more.

In the above method, the refractive index is changed low by the oblique incidence deposition of the one kind of material to deposit three or more layers alternately with the refractive index before the change and the low changed refractive index, and the average is 95% or more in a specific wavelength band according to the incident angle of the beam. It is preferable that a specific reflecting color is formed in a wavelength band having a reflectance and having an average reflectance of 95% or more.

As described above, the method of manufacturing a multilayer thin film and the high-reflection coating method using the same as the present invention, the gradient incidence deposition of one kind of material, can prevent contamination in the chamber because only one kind of material is used as the evaporation material evaporated inside the chamber. In addition, by removing impurities and fine dust remaining in the workpiece, defective products can be reduced, and thus productivity is improved.

Another effect is to deposit multiple layers of dielectric films with varying refractive indices on a glass substrate, depending on the reference wavelength and the angle of incidence of the beam. Reflective color  It is possible to realize various colors in appearance by forming To maximize In addition, it can bring about added value synergistic effect, and it is possible to realize various colors with only one kind of material, thereby simplifying the manufacturing process and reducing costs.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic configuration diagram of a thin film vacuum deposition apparatus for implementing oblique incidence deposition according to an exemplary embodiment of the present invention.

In detail with reference to Figure 1,

Torr를 갖도록 마련된 진공챔버(10) 내부에서 기판(16)을 기판홀더(17)에 고정하여 구성하고, 박막 증착을 위해 증착시킬 물질을 용기(11)에 담는다.In the thin film vacuum deposition apparatus 100 shown in FIG.

The substrate 16 is fixed to the substrate holder 17 in the vacuum chamber 10 provided to have Torr, and the material to be deposited for thin film deposition is contained in the container 11.

Torr의 고진공상태를 유지하기 위해 진공펌프(20)와 산소용기(30)가 진공챔버(10)와 함께 마련되어 진공펌프(20)의 메인밸브(21)에 의해 진공상태를 조절할 수 있고, 진공게이지(22)에 의해 진공챔버(10) 내부의 진공도를 측정할 수 있다.Inside the vacuum chamber 10

In order to maintain the high vacuum state of Torr, the vacuum pump 20 and the oxygen vessel 30 are provided together with the vacuum chamber 10 so that the vacuum state can be controlled by the main valve 21 of the vacuum pump 20, and the vacuum gauge By 22, the degree of vacuum inside the vacuum chamber 10 can be measured.

In this case, a cold cathode vaccum gauge and an ionization vaccum gauge may be used to measure the degree of vacuum, and a thermocouple (not shown) may be provided to measure the substrate temperature or to provide an automatic thermostat ( (Not shown) may be attached to keep the substrate temperature constant.

Meanwhile, the electron gun 12 and the heater 13 may be used as an evaporation source for melting the deposition material contained in the container 11, and when the deposition material is turned into vapor particles by melting by the electron gun 12 or the heater 13, the substrate may be used. The thin film is grown by vapor particles deposited on the substrate 16 fixed to the holder 17.

In this case, the thin film may be deposited by the inclined incidence of the vapor particles by varying the inclined incidence angle α of the container 11 before deposition.

In addition, when the thin film is deposited, the thickness of the thin film is controlled by the mask 14 provided in the vacuum chamber 10 in order to make the thickness of the thin film uniform, and the substrate holder 17 is rotated to be deposited on the substrate 16 by rotation. The thickness of the thin film to be adjusted.

In addition, a crystal oscillator 15 may be provided to measure the physical thickness of the deposited thin film. When the thin film is deposited on the vibrator surface, the thickness change is measured under the assumption that the area and the density are constant, thereby increasing the thickness when the mass is increased. The thickness can be measured by doing this.

On the other hand, the optical thickness of the deposited thin film can be controlled to a thickness of 1/4 wavelength, 1/2 wavelength, etc. with respect to the reference wavelength of the deposition process, in particular by controlling the thickness of 1/4 wavelength symmetrical structure for the optical admittance It facilitates mathematical access and facilitates optical thickness control using optical thickness monitoring.

FIG. 2 is a block diagram of a multilayer thin film having high reflection characteristics manufactured using TiO ₂ as a deposition material using the apparatus of FIG. 1.

3 is a graph of reflectance characteristics for a wavelength band after coating silver on a glass substrate using the apparatus of FIG. 1.

FIG. 4 is a graph showing reflectance characteristics for each wavelength band in a multilayer thin film deposited in the structure shown in FIG. 2 using the apparatus of FIG. 1.

If described in detail with reference to Figures 2 to 4,

TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , HfO ₂ , Nb ₂ O ₅ , Nd having high refractive index as a deposition material for manufacturing a multilayer thin film having high reflection characteristics by using the thin film vacuum deposition apparatus 100 Metal oxides such as ₂ O ₃ can be used.

That is, as shown in FIG. 2, TiO ₂ may be selected as a deposition material, glass may be selected as the substrate 16, and first, silver (Ag) may be coated on the glass substrate.

Here, by coating the silver on the glass substrate, it can be coated in order to exhibit a high reflectance characteristic of at least 95% in a wide wavelength band.

Next, a process of manufacturing a multilayer thin film composed of three layers will be described with reference to FIG. 2.

First, TiO ₂ is deposited using the thin film vacuum deposition apparatus 100 in the silver-coated state, and the refractive index of TiO ₂ is changed to be low as 1.67 by depositing the inclined incident angle α at 65 °.

In this case, the inclined angle of incidence α is equal to the normal direction of the silver-coated surface. TiO ₂ Is the angle formed by the direction of movement of the vapor particles.

Next, the TiO ₂ refractive index is deposited to 2.35 having a relatively high refractive index by depositing the inclined incident angle α at 0 ° on the low refractive index layer.

The last layer adjacent to the air is deposited by changing the incidence angle of incidence α to -65 ° to have a low refractive index again to 1.67, thereby obtaining a graph of reflectance characteristics for each wavelength band as shown in FIG. 4. .

At this time, the layer having a low refractive index (refractive index = 1.67) is deposited by changing the inclined incidence angle α to a zigzag structure (+ 65 °, -65 °) as described above to increase the density of the deposited thin film and improve the anisotropic characteristic. It is desirable to have a reducing effect.

In general, as the incident angle increases, the thin film deposited by the oblique incidence deposition method decreases the effective refractive index of the thin film due to the porous column microstructure of the thin film, but increases the anisotropic characteristic.

Such anisotropy has a problem that it is difficult to use such as a high reflection coating that must exhibit optically isotropic properties.

In addition, such anisotropy is caused by the column microstructure, and because the column microstructure composed of the pillar and the void does not have an isotropic structure, it is caused by the refractive index difference between the pillar and the void.

Therefore, as a method of depositing a thin film having low anisotropy, a method of depositing the film has a small difference between the refractive index of air (1.0) and the refractive index of the deposition material, and maintaining the inclined incident angle (α) so that the pillar microstructure is isotropic. There is a method of rotating and depositing a substrate. According to the present invention, the anisotropic characteristic can be reduced by the zigzag multilayer thin film deposition method as described above.

Meanwhile, a three-layer thin film having a high reflection characteristic having an average reflectance of 95% or more in a wavelength band of 400 nm to 800 nm as shown in FIG. 4 may be manufactured, but this is only one embodiment. Various reflectance characteristics can be obtained by using a refractive index change by incident deposition.

In addition, it can be seen that the three-layer thin film manufactured under the same conditions as in FIG. 2 has a high reflectance in comparison with the graph of reflectance characteristics for each wavelength band in the state where silver is coated on the glass substrate of FIG. 3.

/유리 순으로 증착된 다층 박막의 파장 대역별 반사율 특성을 나타낸 그래프이다.FIG. 5 illustrates that TiO ₂ is used as a deposition material without silver coating on a glass substrate using the apparatus of FIG. 1 according to an exemplary embodiment of the present invention, and the reference wavelength is 510 nm and the incident angle of the beam is 0 °. , air/

It is a graph showing the reflectance characteristics for each wavelength band of the multilayer thin film deposited in the order of / glass.

Referring to FIG. 5, the deposition material TiO ₂ is used without coating silver on the glass substrate, and the reference wavelength is fixed at 510 nm and the incident angle of the beam is fixed at 0 ° to deposit a thin film having a 12-layer structure. In order to alternately have a high refractive index (H) and a low refractive index (L), the deposition is performed by changing the inclined incidence angle α.

At this time, the inclined incident angle α is set to 0 ° so that the high refractive index H is 2.35, and the inclined incident angle α is changed to 65 ° or -65 ° so that the low refractive index L is 1.67. Whenever the layer having the (L) is deposited, the substrate 16 is rotated by 180 ° in the horizontal direction of the surface on which the thin film of the substrate 16 is deposited so as to be deposited in a zigzag structure to increase the density of the thin film. It is preferable.

As illustrated in FIG. 5, the 12-layer thin film has an average reflectance of 95% or more in a wavelength band of 500 nm to 600 nm with respect to a reference wavelength of 510 nm.

FIG. 6 is a graph illustrating reflectance characteristics for each wavelength band when the incident angle of the beam is changed to 30 ° under the condition of FIG. 5.

FIG. 7 is a graph illustrating reflectance characteristics for each wavelength band when the incident angle of the beam is changed to 60 ° under the condition of FIG. 5.

Referring to FIG. 6 and FIG. 7 in detail, by setting only the angle of incidence of the beam at 30 ° and 60 °, respectively, under the same conditions as in FIG. 5, a wavelength band showing an average reflectance of 95% or more compared to FIG. As the angle of incidence of the beam increases, it is shown to move to a lower wavelength band.

Therefore, by changing the angle of incidence of the beam it is possible to manufacture a thin film having a high reflectance only for a specific wavelength, thereby forming a specific reflection color in the wavelength band where the reflectance is high.

That is, in the glass used as the substrate 16, since the reflectance of the visible light band of 400 nm to 700 nm is almost the same, a specific color is observed, but the reflection spectrum is observed differently depending on the wavelength band when the dielectric thin film is deposited in multiple layers. The color of the wavelength band is stimulated by our eyes with the reflection intensity equal to the reflection coefficient at that wavelength, and the color is observed.

For example, in the visible light band incident on the 12-layer thin film of TiO ₂ , which is the dielectric thin film, the reflection at 490 nm wavelength is relatively higher than that at other wavelengths. The intensity of the band will increase, resulting in the blue color of the reflecting color.

FIG. 8 is a graph showing reflectance characteristics for each wavelength band when the reference wavelength is changed to 600 nm under the condition of FIG. 5.

FIG. 9 is a graph showing reflectance characteristics for each wavelength band when the reference wavelength is changed to 650 nm under the condition of FIG. 5.

Referring to Figures 8 and 9 in detail,

The reflectance characteristic graphs shown in FIGS. 8 and 9 show reflection characteristics for each wavelength band when the reference wavelength is set to 600 nm and 650 nm, respectively, in the thin film condition of the 12-layer structure of FIG. 5.

That is, as the reference wavelength increases, it can be seen that a specific wavelength band showing an average reflectance of 95% or more appears in a high band. As a result, the incident wave is incident on the thin film of the TiO ₂ 12-layer structure under the conditions shown in FIG. Among the lights of the visible light band, the reflection at the 650 nm wavelength is relatively more than at the other wavelengths, and thus the intensity of the 650 nm wavelength band among the intensities of the reflected light will be increased, so that the red color of the reflected color is observed.

/유리 순으로 증착되며, 이때 저굴절률(L)은 1.67으로 증착된 다층박막의 파장 대역별 반사율 특성을 나타낸 그래프이다.10 shows TiO ₂ as a deposition material on a glass substrate according to another preferred embodiment of the present invention, the reference wavelength is 510 nm, the incident angle of the beam is 0 °, air /

The low refractive index (L) is a graph showing reflectance characteristics for each wavelength band of the multilayer thin film deposited at 1.67.

FIG. 11 is a graph illustrating reflectance characteristics of wavelength bands of the multilayer thin film deposited by changing the low refractive index L to 1.46 under the conditions of FIG. 10.

Referring to FIG. 10 and FIG. 11, FIG. 10 is a thin film having a 17-layer structure of TiO ₂ manufactured by varying the number of thin films under the condition of FIG. 5, and has a high refractive index (H) of 2.35 on the glass substrate. After the deposition, the inclination angle (α = 65 ° or α = -65 °) is changed so that the low refractive index (L) becomes 1.67, and the high refractive index (H) is deposited to 2.35 for each layer. A thin film having a 17-layer structure in which 16 more layers were further deposited alternately with a low refractive index (L) and a high refractive index (H) was produced.

In this case, when the layer having the low refractive index (L) is preferably deposited at an inclined angle of inclination (α = 65 ° or α = -65 °) to form a zigzag structure with the low refractive index (L) layer deposited first .

As shown in FIG. 10, the thin film having the 17-layer structure manufactured as described above exhibits 100% reflectivity in the wavelength range of 450 nm to 550 nm.

FIG. 11 is a thin film having a 17-layer structure formed by depositing the inclined incident angle α at 83 ° or −83 ° such that the low refractive index L is 1.46 under the same conditions as in FIG. 10. As can be seen from the broad range of wavelengths from the near-infrared region to near-infrared region, the average reflectance is higher than 95%.

At this time, preferably, it is deposited so as to form an interlayer zigzag structure (α = 83 ° or −83 °) having the low refractive index (L).

Therefore, when the oblique incidence angle (α) of TiO ₂ , which is a deposition material, is increased, the refractive index of the deposition material is changed to be close to the refractive index of air, thereby obtaining high efficiency reflectance and high average reflectance in a wide wavelength band. have.

/유리 순으로 변경하여 증착된 다층 박막의 파장 대역별 반사율 특성을 나타낸 그래프이다.FIG. 12 shows the air /

It is a graph showing reflectance characteristics for each wavelength band of the multilayer thin film deposited in the order of / glass.

12 will be described in detail with reference to FIG. 12, but the low refractive index L of FIG. 11 is deposited to be 1.46, but the thin film is formed of 16 layers by reducing the number of layers of the thin film.

At this time, it is preferable that the deposition is performed by varying the inclined incident angle (α = 83 ° or -83 °) to form an interlayer zigzag structure having a low refractive index (L = 1.46).

As shown in FIG. 12, the thin film having the 16-layer structure exhibits a reflectance close to 100% in the entire visible light region, and thus may be applied to the high reflection mirror in the visible light region.

Although one preferred embodiment of the present invention has been described above, it is clear that the present invention may use various changes, modifications, and equivalents, and may be applied in the same manner by appropriately modifying the above embodiments. Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

1 is a schematic configuration diagram of a thin film vacuum deposition apparatus for implementing oblique incidence deposition according to an exemplary embodiment of the present invention.

FIG. 2 is a block diagram of a multilayer thin film having high reflection characteristics manufactured using TiO ₂ as a deposition material using the apparatus of FIG. 1.

3 is a graph of reflectance characteristics for a wavelength band after coating silver on a glass substrate using the apparatus of FIG. 1.

FIG. 4 is a graph showing reflectance characteristics for each wavelength band in a multilayer thin film deposited in the structure shown in FIG. 2 using the apparatus of FIG. 1.

/유리 순으로 증착된 다층 박막의 파장 대역별 반사율 특성을 나타낸 그래프이다.FIG. 5 illustrates that TiO ₂ is used as a deposition material without silver coating on a glass substrate using the apparatus of FIG. 1 according to an exemplary embodiment of the present invention, and the reference wavelength is 510 nm and the incident angle of the beam is 0 °. , air/

It is a graph showing the reflectance characteristics for each wavelength band of the multilayer thin film deposited in the order of / glass.

FIG. 6 is a graph illustrating reflectance characteristics for each wavelength band when the incident angle of the beam is changed to 30 ° under the condition of FIG. 5.

FIG. 7 is a graph illustrating reflectance characteristics for each wavelength band when the incident angle of the beam is changed to 60 ° under the condition of FIG. 5.

FIG. 8 is a graph showing reflectance characteristics for each wavelength band when the reference wavelength is changed to 600 nm under the condition of FIG. 5.

FIG. 9 is a graph showing reflectance characteristics for each wavelength band when the reference wavelength is changed to 650 nm under the condition of FIG. 5.

/유리 순으로 증착되며, 이때 저굴절률(L)은 1.67으로 증착된 다층박막의 파장 대역별 반사율 특성을 나타낸 그래프이다.10 shows TiO ₂ as a deposition material on a glass substrate according to another preferred embodiment of the present invention, the reference wavelength is 510 nm, the incident angle of the beam is 0 °, air /

The low refractive index (L) is a graph showing reflectance characteristics for each wavelength band of the multilayer thin film deposited at 1.67.

FIG. 11 is a graph illustrating reflectance characteristics of wavelength bands of the multilayer thin film deposited by changing the low refractive index L to 1.46 under the conditions of FIG. 10.

/유리 순으로 변경하여 증착된 다층 박막의 파장 대역별 반사율 특성을 나타낸 그래프이다.FIG. 12 shows the air /

It is a graph showing reflectance characteristics for each wavelength band of the multilayer thin film deposited in the order of / glass.

<Description of reference numerals for main parts of the drawings>

10 vacuum chamber 11: container

12: electron gun 13: heater

14 mask 15 crystal oscillator

16 substrate 17 substrate holder

20: vacuum pump 21: main valve

22: vacuum gauge 30: oxygen container

100: thin film vacuum deposition apparatus

Claims (8)

The deposition of one kind of material on a substrate, but the gradient incident angle (α) by the gradient incidence deposition by varying the refractive index to produce a multilayer thin film deposited by three or more layers characterized in that the gradient incident deposition Multi-layer thin film manufacturing method using. By changing the incidence incidence angle (α) by the inclined incidence deposition with one kind of material on the substrate to produce a multi-layer thin film of three or more layers by varying the refractive index, according to the multilayer thin film deposited by the change of the refractive index, ultraviolet region, visible light region And a high reflection coating (High Reflection Coating) to have an average reflectance of at least 95% in the wavelength band of the infrared region. The method according to claim 1 or 2, The one kind of material is a metal oxide having high refractive index characteristics such as TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , HfO ₂ , Nb ₂ O ₅ , Nd ₂ O ₃ , and is inclined when depositing a metal oxide having high refractive index characteristics. A method of manufacturing a multilayer thin film using oblique incidence deposition of a kind of material, characterized in that the refractive index is changed by changing the incident angle α to be alternately deposited into a layer having a high refractive index and a layer having a low refractive index. Reflective coating method. The method according to claim 1 or 2, In order to increase the density of the thin film having the porous pillar microstructure by gradient incidence deposition by alternating deposition of one kind of material on the substrate, and to change the refractive index and the uniform thickness, the substrate is once deposited in a fixed state. A method of manufacturing a multilayer thin film using oblique incidence deposition of a material, and a highly reflective coating method using the same, characterized by depositing by rotating or depositing a tilt incident angle α by a zigzag structure of + α and -α. The method according to claim 1 or 2, Method for manufacturing a multilayer thin film using gradient incidence deposition of a material, characterized in that the optical phase thickness of the thin film deposited by the one material is controlled to have a 1/4 wavelength thickness and using the same High reflection  Coating method. The method of claim 2, After depositing a metal such as silver (Ag) on the substrate before depositing the one kind of material, the refractive index is changed low by the gradient incident deposition of one kind of material, alternating at least three layers with the refractive index before the change and the low changed refractive index. The high reflection coating method having an average of 95% or more of reflectance in the wavelength range of the ultraviolet region, the visible region and the infrared region by vapor deposition. The method of claim 2, Glass is used as a substrate, and the refractive index is changed low by the gradient incidence deposition of the one kind of material on the glass substrate to deposit three or more layers alternately with the refractive index before the change and the lower changed refractive index, but in a specific wavelength band according to the reference wavelength. A method of high reflection coating, characterized in that a specific reflecting color is formed in a wavelength band having an average reflectance of at least 95% and a reflectance of at least 95%. The method of claim 7, wherein By changing the refractive index low by the oblique incidence deposition of the one type of material to deposit three or more layers alternately with the refractive index before the change and the low changed refractive index, having an average reflectance of 95% or more in a specific wavelength band according to the incident angle of the beam , A high reflection coating method characterized in that a specific reflection color is formed in a wavelength band having an average reflectance of 95% or more.

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