Method for forming film on glass article, reflecting mirror, and endoscope

Abstract

A method for forming a film on a glass article is provided, which can increase the reflectance and weather resistance of a reflecting mirror. [Solution] The method for forming a film on a glass article of the present invention is characterized by comprising a reflective film forming step of forming a reflective film 6, which is an Ag film, on a glass article 2, a first protective layer forming step of forming a first protective layer 7A, which is an aluminum oxide film, directly on the reflective film 6 without using ion-assisted vapor deposition or ion plating vapor deposition, and a second protective layer forming step of forming a second protective layer 7B, which is a silicon oxide film, directly on the first protective layer 7A.

Description

[Technical Field]

[0001] The present invention relates to a method for forming a film on a glass article, a reflecting mirror, and an endoscope. [Background technology]

[0002] Reflecting mirrors have been widely used as optical components. Reflecting mirrors are known to use thin metal films formed by vacuum deposition. Films made of silver or aluminum have particularly high reflectance. Therefore, when the reflectance of a reflecting mirror needs to be increased, films made of silver or aluminum are often used.

[0003] For example, in the reflecting mirror described in Patent Document 1 below, a Cr layer, an Ag layer, an Al2O3 layer, a ZrO2 layer, and an SiO2 layer are laminated in this order on a glass substrate. In this reflecting mirror, the Ag layer is used as a reflective film. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-127004 Summary of the Invention [Problem to be solved by the invention]

[0005] Depending on the application of the reflecting mirror, the reflecting mirror may be sterilized in an autoclave. When the reflecting mirror is sterilized in an autoclave, the reflecting mirror is placed in a high-temperature, high-humidity environment for a long period of time. Therefore, the reflecting mirror that is to be sterilized in an autoclave must have sufficient weather resistance.

[0006] However, when an Ag film is used to increase the reflectance of a reflecting mirror, it is difficult to make the reflecting mirror weather-resistant enough to withstand autoclave sterilization.

[0007] An object of the present invention is to provide a method for forming a film on a glass article, which can increase the reflectivity and weather resistance of a reflecting mirror. Another object of the present invention is to provide a reflecting mirror, which can increase the reflectivity and weather resistance. Yet another object of the present invention is to provide an endoscope, which can increase the reflectivity and weather resistance of a reflecting mirror and suppress deterioration of visibility. [Means for solving the problem]

[0008] A method for forming a film on a glass article according to aspect 1 of the present invention is characterized by comprising: a reflective film forming step of forming a reflective film, which is an Ag film, on the glass article; a first protective layer forming step of forming a first protective layer, which is an aluminum oxide film, directly on the reflective film without using ion-assisted vapor deposition or ion plating vapor deposition; and a second protective layer forming step of forming a second protective layer, which is a silicon oxide film, directly on the first protective layer.

[0009] In the method for forming a film on a glass article of the second aspect, in the first aspect, it is preferable to use ion-assisted deposition or ion plating deposition in the second protective layer forming step.

[0010] In the method of forming a film on a glass article of aspect 3, in aspect 1 or 2, it is preferable that the average film formation rate for forming the reflective film in the reflective film formation step is 1 nm / s or more and 20 nm / s or less.

[0011] In the method of forming a film on a glass article of aspect 4, in any one of aspects 1 to 3, it is preferable that in the reflective film forming step, the temperature of the glass article is set to 100°C or less, and ion-assisted vapor deposition and ion plating vapor deposition are not used.

[0012] In the method of forming a film on a glass article of aspect 5, in any one of aspects 1 to 4, it is preferable that the method further includes a first adhesion layer formation step, prior to the reflective film formation step, of forming a first adhesion layer, which is a silicon oxide film, on the glass article at a temperature of 100°C or more and 400°C or less by ion-assisted vapor deposition or ion plating vapor deposition.

[0013] In the method of forming a film on a glass article of aspect 6, in aspect 5, it is preferable to further include a second adhesion layer forming step of forming a second adhesion layer, which is an aluminum oxide film, on the first adhesion layer between the first adhesion layer forming step and the reflective film forming step.

[0014] A reflecting mirror according to a seventh aspect of the present invention comprises a glass article having a first main surface and a second main surface facing each other, and a multilayer film provided on the first main surface of the glass article and including a reflective functional layer which is a laminate having the function of reflecting light, wherein the reflective functional layer includes a reflective film which is an Ag film located closest to the glass article, a first protective layer which is an aluminum oxide film laminated directly on the reflective film, and a second protective layer which is a silicon oxide film laminated directly on the first protective layer.

[0015] In the reflecting mirror of aspect 8, it is preferable that, in aspect 7, the multilayer film further includes a first adhesion layer that is a silicon oxide film and is laminated directly on the first main surface of the glass article, and a second adhesion layer that is an aluminum oxide film and is laminated directly on the first adhesion layer, and that the reflective function layer is laminated directly on the second adhesion layer.

[0016] In the reflecting mirror of embodiment 9, in embodiment 7 or 8, it is preferable that the difference in wavelength at which the reflectance is 96% before being placed in an environment of a temperature of 135°C and a humidity of 94% and after being placed in that environment for 50 hours is 0 nm or more and 20 nm or less.

[0017] In the reflecting mirror of aspect 10, in any one of aspects 7 to 9, when the layer in the multilayer film farthest from the glass article is a first outermost layer and the layer closest to the glass article is a second outermost layer, and when the reflectance of the multilayer film measured from the first outermost layer side is a first reflectance and the reflectance of the multilayer film measured from the second outermost layer side is a second reflectance, it is preferable that both the first reflectance and the second reflectance are 96% or more in a wavelength range having a width of 500 nm.

[0018] In the reflecting mirror of embodiment 11, in embodiment 10, it is preferable that the difference in wavelength at which the first reflectance is 96% is 0 nm or more and 20 nm or less, and the difference in wavelength at which the second reflectance is 96% is 0 nm or more and 20 nm or less, before and after being placed in an environment with a temperature of 135°C and a humidity of 94% for 50 hours.

[0019] In the reflecting mirror of aspect 12, in any one of aspects 7 to 11, it is preferable that in the multilayer film, the layer farthest from the glass article is a first outermost layer, the layer closest to the glass article is a second outermost layer, and the arithmetic mean roughness Ra of the first outermost layer is 5 nm or less.

[0020] An endoscope according to a thirteenth aspect of the present invention is characterized by including a reflecting mirror according to any one of the seventh to twelfth aspects. [Effects of the Invention]

[0021] The method of forming a film on a glass article according to the present invention can increase the reflectivity and weather resistance of a reflecting mirror.The reflecting mirror according to the present invention can increase the reflectivity and weather resistance.The endoscope according to the present invention can increase the reflectivity and weather resistance of a reflecting mirror and suppress deterioration of visibility. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic front cross-sectional view of a reflecting mirror according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a schematic front cross-sectional view of a reflecting mirror according to a first modified example of the first embodiment of the present invention. [Figure 3] FIG. 3 is a schematic front cross-sectional view of a reflecting mirror according to a second modified example of the first embodiment of the present invention. [Figure 4] 4(a) and 4(b) are schematic front cross-sectional views for explaining a first adhesion layer deposition step and a second adhesion layer deposition step in a film deposition method for a glass article according to a second embodiment of the present invention. [Figure 5] Figures 5(a) to 5(c) are schematic front cross-sectional views for explaining the reflective film forming process, the first protective layer forming process, and the second protective layer forming process in the method for forming a film on a glass article according to the second embodiment of the present invention. [Figure 6] FIG. 6 is a diagram showing the reflectance before and after autoclave sterilization in Example 1. [Figure 7] FIG. 7 is a diagram showing the reflectance before and after autoclave sterilization in Example 2. [Figure 8] FIG. 8 is a diagram showing the reflectance before and after autoclave sterilization in Example 3. [Figure 9] FIG. 9 is a diagram showing the reflectance before and after autoclave sterilization in a comparative example. [Figure 10] FIG. 10 is a diagram showing the relationship between the temperature of the glass article when forming an Ag film and the reflectance of the reflecting mirror at a wavelength of 500 nm. [Figure 11] FIG. 11 is a graph showing the relationship between the temperature of the glass article when forming an Ag film and the arithmetic mean roughness Ra of the first outermost layer. [Figure 12] FIG. 12 is a diagram showing the relationship between the reflectance of the reflecting mirror at a wavelength of 500 nm and the arithmetic mean roughness Ra of the first outermost layer. [Figure 13] FIG. 13 is a schematic front cross-sectional view for explaining the first reflectance and the second reflectance. [Figure 14]FIG. 14 is a diagram showing the first reflectance and the second reflectance of a reflecting mirror whose first outermost layer has an arithmetic mean roughness Ra of 1 nm. [Figure 15] FIG. 15 is a diagram showing the first reflectance and the second reflectance of a reflecting mirror in which the arithmetic mean roughness Ra of the first outermost layer is 7 nm. DETAILED DESCRIPTION OF THE INVENTION

[0023] Preferred embodiments will be described below. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments. In addition, in each drawing, components having substantially the same functions may be referred to by the same reference numerals.

[0024] (reflector) (First embodiment) FIG. 1 is a schematic front cross-sectional view of a reflecting mirror according to a first embodiment of the present invention.

[0025] The reflecting mirror 1 includes a glass article 2 and a multilayer film 3. In this embodiment, the glass article 2 is a glass substrate. The shape of the glass article 2 in this embodiment is a rectangular plate shape. A rectangular plate shape refers to a plate shape in which the main surface has a rectangular shape. However, the shape of the glass article 2 is not limited to the above, and may be, for example, a disk shape, a lens shape, a prism shape, or the like.

[0026] The glass article 2 has a first main surface 2a and a second main surface 2b. The first main surface 2a and the second main surface 2b face each other. A multilayer film 3 is provided on the first main surface 2a of the glass article 2. Specifically, the multilayer film 3 has an adhesive layer 4 and a reflective function layer 5. The reflective function layer 5 is a laminate having a function of reflecting light.

[0027] As shown in FIG. 1 , an adhesion layer 4 is laminated on a first main surface 2a of a glass article 2. A reflective function layer 5 is laminated on the adhesion layer 4. In this specification, when it is stated that a certain member is laminated on another member, this includes cases where the other member is laminated directly on the certain member and cases where the other member is laminated indirectly on the certain member. In this embodiment, the adhesion layer 4 is laminated directly on the first main surface 2a of the glass article 2. The reflective function layer 5 is laminated directly on the adhesion layer 4.

[0028] Specifically, the adhesion layer 4 includes a first adhesion layer 4A and a second adhesion layer 4B. The first adhesion layer 4A is laminated directly on the first main surface 2a of the glass article 2. The second adhesion layer 4B is laminated directly on the first adhesion layer 4A.

[0029] More specifically, the first adhesion layer 4A is a SiO2 film. The second adhesion layer 4B is an Al2O3 film. The compositions of the first adhesion layer 4A and the second adhesion layer 4B are not limited to those described above. For example, the first adhesion layer 4A may be a silicon oxide film other than a SiO2 film. The second adhesion layer 4B may be an aluminum oxide film other than an Al2O3 film. However, the number of layers in the adhesion layer 4 is not limited to two. The adhesion layer 4 may be, for example, a single dielectric layer or a laminate of three or more layers.

[0030] Specifically, the reflective function layer 5 has a reflective film 6 and a protective layer 7. The reflective film 6 is indirectly laminated on the first main surface 2a of the glass article 2 via an adhesive layer 4. The protective layer 7 is directly laminated on the reflective film 6.

[0031] More specifically, the protective layer 7 includes a first protective layer 7A and a second protective layer 7B. The first protective layer 7A is stacked directly on the reflective film 6. The second protective layer 7B is stacked directly on the first protective layer 7A.

[0032] More specifically, the reflective film 6 is an Ag film. The first protective layer 7A is an Al2O3 film. The second protective layer 7B is an SiO2 film. However, the compositions of the first protective layer 7A and the second protective layer 7B are not limited to those described above. The first protective layer 7A may be an aluminum oxide film. The second protective layer 7B may be a silicon oxide film. However, the number of layers in the protective layer 7 is not limited to two. The protective layer 7 may be, for example, a laminate of three or more layers.

[0033] In this embodiment, the reflective function layer 5 is laminated directly on the second adhesive layer 4B of the adhesive layer 4. The adhesive layer 4 does not necessarily have to be provided. The reflective function layer 5 may be provided directly on the first main surface 2a of the glass article 2.

[0034] The multilayer film 3 has a pair of outermost layers. Specifically, the layer in the multilayer film 3 that is farthest from the glass article 2 is the first outermost layer. The layer in the multilayer film 3 that is closest to the glass article 2 is the second outermost layer. The first outermost layer of the reflecting mirror 1 is the second protective layer 7B. The second outermost layer of the reflecting mirror 1 is the first adhesive layer 4A.

[0035] Examples of the thickness of each layer in the multilayer film 3 are shown below. The thickness of the first adhesive layer 4A can be, for example, 1 nm or more and 50 nm or less. The thickness of the second adhesive layer 4B can be, for example, 10 nm or more and 50 nm or less. The thickness of the reflective film 6 can be, for example, 50 nm or more and 500 nm or less. The thickness of the first protective layer 7A can be, for example, 10 nm or more and 100 nm or less. The thickness of the second protective layer 7B can be, for example, 20 nm or more and 300 nm or less.

[0036] Herein, when simply referring to reflectance without any particular specification, the reflectance refers to the reflectance measured from the first outermost layer side. The reflecting mirror of the present invention can achieve both high reflectance and high weather resistance. The reflecting mirror of the present invention may have the following layered structure shown in FIG. 1 . That is, the reflective function layer 5 may include a reflective film 6 that is an Ag film, a first protective layer 7A that is an aluminum oxide film and is laminated directly on the reflective film 6, and a second protective layer 7B that is a silicon oxide film and is laminated directly on the first protective layer 7A.

[0037] Below, first and second modified examples of the first embodiment, which differ from the first embodiment only in the configuration of the protective layer, are shown. The first and second modified examples can also achieve high reflectance and weather resistance.

[0038] (First Modification) In the first modified example shown in FIG. 2, the protective layer 17 includes a first protective layer 7A, a second protective layer 7B, a third protective layer 17C, and a fourth protective layer 17D. From the reflective film 6 side, the first protective layer 7A, the second protective layer 7B, the third protective layer 17C, and the fourth protective layer 17D are directly stacked in this order. The first protective layer 7A and the second protective layer 7B are configured in the same manner as in the first embodiment. Therefore, the reflective film 6, which is an Ag film, the first protective layer 7A, which is an aluminum oxide film, and the second protective layer 7B, which is a silicon oxide film, are directly stacked in this order.

[0039] The third protective layer 17C is a TiO2 film. The fourth protective layer 17D is a SiO2 film. However, the compositions of the third protective layer 17C and the fourth protective layer 17D are not limited to the above.

[0040] (Second Modification) 3 differs from the first modification only in that protective layer 27 includes fifth protective layer 27E. In protective layer 27, first protective layer 7A, second protective layer 7B, third protective layer 17C, fourth protective layer 17D, and fifth protective layer 27E are stacked directly in this order from the reflective film 6 side. In this modification, reflective film 6, which is an Ag film, first protective layer 7A, which is an aluminum oxide film, and second protective layer 7B, which is a silicon oxide film, are stacked directly in this order.

[0041] The fifth protective layer 27E is a TiO2 film, although the composition of the fifth protective layer 27E is not limited to the above.

[0042] In the first and second modified examples, the thickness of the third protective layer 17C can be, for example, 20 nm or more and 100 nm or less. The thickness of the fourth protective layer 17D can be, for example, 20 nm or more and 300 nm or less. In the second modified example, the thickness of the fifth protective layer 27E can be, for example, 20 nm or more and 300 nm or less.

[0043] In the present invention, the arithmetic mean roughness Ra of the first outermost layer in the multilayer film of the reflecting mirror is preferably 5 nm or less, and more preferably 3 nm or less. In this case, the reflectance of the reflecting mirror can be effectively increased. In this specification, the arithmetic mean roughness Ra conforms to JIS B 0601:2013.

[0044] Incidentally, the glass article 2 shown in FIG. 1 preferably has translucency to visible light, for example. In this case, visible light can be incident on the reflective function layer 5 from the glass article 2 side. That is, visible light can be incident on the reflective function layer 5 not only from the first outermost layer side of the multilayer film 3 but also from the second outermost layer side. Therefore, the reflecting mirror 1 can reflect both incident light from the first outermost layer side and incident light from the second outermost layer side. In this case, the range of uses of the reflecting mirror 1 can be suitably widened. This also applies to reflecting mirrors according to the present invention other than the first embodiment.

[0045] The glass used for the glass article 2 is not particularly limited, but may be, for example, borosilicate glass, aluminosilicate glass, or quartz glass. In these cases, visible light can be suitably incident on the reflective function layer 5 from the glass article 2 side.

[0046] A method for manufacturing a reflecting mirror according to the first embodiment will be described below. This manufacturing method is a method for forming a film on a glass article according to the second embodiment of the present invention.

[0047] (Method of forming a film on a glass article) (Second embodiment) 4(a) and 4(b) are schematic cross-sectional front views illustrating a first adhesive layer forming step and a second adhesive layer forming step in a method for forming a film on a glass article according to a second embodiment of the present invention. 5(a) to 5(c) are schematic cross-sectional front views illustrating a reflective film forming step, a first protective layer forming step and a second protective layer forming step in a method for forming a film on a glass article according to the second embodiment.

[0048] As shown in FIG. 4(a), a glass article 2 is prepared. Next, the glass article 2 is heated to a temperature of 100°C or higher and 400°C or lower. More specifically, in this embodiment, the temperature of the glass article 2 is set to approximately 250°C. Next, a first adhesive layer 4A, which is a silicon oxide film, is formed on the first main surface 2a of the glass article 2.

[0049] In this specification, the term "forming a film on a certain member" includes forming a film on another member directly, and forming a film on a certain member indirectly. In this embodiment, the first adhesive layer 4A is formed directly on the first main surface 2a of the glass article 2.

[0050] More specifically, the first adhesion layer 4A is formed on the first main surface 2a of the glass article 2 by ion-assisted vapor deposition or ion plating vapor deposition. This can improve the adhesion of the first adhesion layer 4A to the glass article 2. However, it is not necessary to use ion-assisted vapor deposition or ion plating vapor deposition to form the first adhesion layer 4A.

[0051] Next, as shown in FIG. 4(b), the second adhesive layer 4B is formed directly on the first adhesive layer 4A. More specifically, the second adhesive layer 4B is formed on the first adhesive layer 4A using ion-assisted vapor deposition or ion plating vapor deposition. This increases the adhesion of the second adhesive layer 4B to the first adhesive layer 4A. However, it is not necessary to use ion-assisted vapor deposition or ion plating vapor deposition to form the second adhesive layer 4B.

[0052] Next, the temperature of the glass article 2 is set to 100° C. or lower. More specifically, in this embodiment, the temperature of the glass article 2 is set to 80° C. or lower.

[0053] The first adhesion layer forming step and the second adhesion layer forming step do not necessarily have to be performed, and the reflective film 6 may be formed directly on the first main surface 2a of the glass article 2.

[0054] Next, as shown in FIG. 5(a), a reflective film 6 is formed on the adhesion layer 4 without using ion-assisted deposition or ion plating deposition. That is, in this film formation method, at least ion-assisted deposition and ion plating deposition are not used to form the reflective film 6. The reflective film 6 can be formed, for example, by vapor deposition or sputtering. In this embodiment, the average film formation rate for forming the reflective film 6 is set to 5 nm / s or more. Note that the average film formation rate for forming the reflective film 6 is not limited to the above.

[0055] When the first adhesive layer 4A and the second adhesive layer 4B are formed, the temperature of the glass article 2 is set to 100° C. or more and 400° C. or less. On the other hand, when the reflective film 6 is formed, the temperature of the glass article 2 is set to 100° C. or less. Note that the temperature of the glass article 2 when the first adhesive layer 4A, the second adhesive layer 4B, and the reflective film 6 are formed is not limited to the above.

[0056] Next, as shown in FIG. 5(b), the first protective layer 7A is formed directly on the reflective film 6 without using ion-assisted deposition or ion plating deposition. That is, in this film formation method, at least ion-assisted deposition and ion plating deposition are not used to form the first protective layer 7A. The first protective layer 7A can be formed by, for example, vapor deposition or sputtering. From the viewpoints of reducing collision energy during film formation, preventing excessive energy from being imparted to the Ag film, and suppressing Ag crystal growth in the Ag film, it is preferable to form the layer by vapor deposition.

[0057] Next, as shown in Figure 5(c), a second protective layer 7B is formed directly on the first protective layer 7A using ion-assisted deposition or ion plating deposition. However, ion-assisted deposition or ion plating deposition does not necessarily have to be used to form the second protective layer 7B. In this way, the reflecting mirror 1 is obtained.

[0058] The method for forming a film on a glass article according to the second embodiment can be used to obtain the reflecting mirror 11 according to the first modification of the first embodiment shown in FIG. 2. Specifically, a film is formed on the glass article 2 in the same manner as in the methods shown in FIGS. 4(a), 4(b), and 5(a) to 5(c). Thereafter, a third protective layer 17C is formed on the second protective layer 7B, for example, by ion-assisted vapor deposition or ion plating vapor deposition. Next, a fourth protective layer 17D is formed on the third protective layer 17C, for example, by ion-assisted vapor deposition or ion plating vapor deposition. However, the third protective layer 17C and the fourth protective layer 17D do not necessarily have to be formed by ion-assisted vapor deposition or ion plating vapor deposition.

[0059] The method for forming a film on a glass article according to the second embodiment can also be used to obtain the reflecting mirror 21 according to the second modified example of the first embodiment shown in Fig. 3. Specifically, for example, a film is formed on the glass article 2 in the same manner as in the case of obtaining the reflecting mirror 11 according to the first modified example. Thereafter, a fifth protective layer 27E is formed on the fourth protective layer 17D, for example, by using ion-assisted vapor deposition or ion plating vapor deposition. However, ion-assisted vapor deposition or ion plating vapor deposition does not necessarily have to be used to form the fifth protective layer 27E.

[0060] The second embodiment is characterized in that a first protective layer 7A, which is an aluminum oxide film, is formed directly on the reflective film 6, which is an Ag film, without using ion-assisted deposition or ion plating deposition, and a second protective layer 7B, which is a silicon oxide film, is formed directly on the first protective layer 7A. This makes it possible to achieve both high reflectivity and high weather resistance in the reflecting mirror 1. Note that by using the method for forming a film on a glass article according to the second embodiment, it is possible to similarly increase the reflectivity and weather resistance in the reflecting mirror 11 shown in FIG. 2 and the reflecting mirror 21 shown in FIG. 3. These details are described below.

[0061] Reflecting mirrors having the configurations of the first embodiment, the first modified example of the first embodiment, and the second modified example were fabricated using the method for forming a film on a glass article according to the second embodiment. Of the fabricated reflecting mirrors, reflecting mirror 1 having the configuration of the first embodiment will be referred to as Example 1 below. Reflecting mirror 11 having the configuration of the first modified example will be referred to as Example 2. Reflecting mirror 21 having the configuration of the second modified example will be referred to as Example 3.

[0062] Meanwhile, a reflecting mirror of a comparative example was also prepared. The comparative example differs from Example 1 in that the material of the first protective layer is TiO2. In the comparative example, a glass article, an SiO2 film, an Al2O3 film, an Ag film, a TiO2 film, and an SiO2 film are directly stacked in this order. The stacking configurations and thicknesses of each layer in the reflecting mirrors of Examples 1, 2, 3, and the comparative example are as shown in Table 1.

[0063] [Table 1]

[0064] The weather resistance of the reflecting mirrors in Examples 1, 2, and 3 and the Comparative Example was compared. Specifically, the reflectance of each reflecting mirror was measured before and after autoclave sterilization. The autoclave sterilization of each reflecting mirror was performed by placing each reflecting mirror in an environment with a temperature of 135°C and a humidity of 94% for 50 hours. The reflectance of the reflecting mirror was measured using an integrating sphere-equipped self-recording spectrophotometer (manufactured by Hitachi, Ltd., model number "UH-4150") with an incident angle of unpolarized light of 45°.

[0065] Fig. 6 is a diagram showing the reflectance before and after autoclave sterilization in Example 1. Fig. 7 is a diagram showing the reflectance before and after autoclave sterilization in Example 2. Fig. 8 is a diagram showing the reflectance before and after autoclave sterilization in Example 3. Fig. 9 is a diagram showing the reflectance before and after autoclave sterilization in a comparative example.

[0066] As shown in Figure 6, the reflectance of the reflecting mirror 1 of Example 1 is high, at 96% or more, at wavelengths of 445 nm or more and 700 nm or less, both before and after autoclave sterilization. Moreover, the reflectance at any wavelength remains almost unchanged before and after autoclave sterilization. In other words, the reflectance of the reflecting mirror 1 remains almost unchanged at any wavelength before and after being placed in an environment with a temperature of 135°C and a humidity of 94% for 50 hours.

[0067] Hereinafter, the wavelength at which the reflectance of a reflecting mirror is 96% may be used as an indicator of the weather resistance of a reflecting mirror. More specifically, the change in this wavelength before and after autoclave sterilization may be used as an indicator of the weather resistance of a reflecting mirror. For example, the difference in the wavelength at which the reflectance of the reflecting mirror is 96% before and after placing the reflecting mirror in an environment with a temperature of 135°C and humidity of 94% for 50 hours is preferably 0 nm or more and 20 nm or less, and more preferably 0 nm or more and 15 nm or less. In this case, the weather resistance of the reflecting mirror is particularly high.

[0068] As shown in Figure 6, before the reflecting mirror 1 is sterilized in an autoclave, the wavelength at which the reflectance of the reflecting mirror 1 is 96% is 445 nm. On the other hand, after the reflecting mirror 1 is sterilized in an autoclave, the wavelength at which the reflectance of the reflecting mirror 1 is 96% is 437 nm. Therefore, the wavelength at which the reflectance of the reflecting mirror 1 is 96% changes by only 8 nm before and after the reflecting mirror 1 is placed in an environment with a temperature of 135°C and a humidity of 94% for 50 hours. Thus, the weather resistance of the reflecting mirror 1 is high.

[0069] 7, the reflectance of reflecting mirror 11 of Example 2 is as high as 96% or more in the wavelength range of 482 nm or more and 700 nm or less before autoclave sterilization. Even after autoclave sterilization, the reflectance of reflecting mirror 11 is as high as 96% or more in the wavelength range of 474 nm or more and 700 nm or less.

[0070] For example, before autoclave sterilization of reflecting mirror 11, the wavelength at which reflectance of reflecting mirror 11 is 96% is 482 nm. On the other hand, after autoclave sterilization of reflecting mirror 11, the wavelength at which reflectance of reflecting mirror 11 is 96% is 474 nm. Therefore, the wavelength at which reflectance of reflecting mirror 11 is 96% changes by only 8 nm before and after autoclave sterilization. Thus, reflecting mirror 11 has high weather resistance.

[0071] In Example 2, the effect is obtained that the reflectance of the reflecting mirror 11 becomes higher after the autoclave sterilization process than before the autoclave sterilization process.

[0072] As shown in FIG. 8, the reflectance of the reflecting mirror 21 of Example 3 is high, at 97% or more, at wavelengths of 420 nm or more and 700 nm or less, regardless of whether it is before or after autoclave sterilization.

[0073] For example, before autoclave sterilization of reflecting mirror 21, the wavelength at which reflectance of reflecting mirror 21 is 96% is 409 nm. On the other hand, after autoclave sterilization of reflecting mirror 21, the wavelength at which reflectance of reflecting mirror 21 is 96% is 402 nm. Therefore, the wavelength at which reflectance of reflecting mirror 21 is 96% changes by only 7 nm before and after autoclave sterilization. Thus, reflecting mirror 21 has high weather resistance.

[0074] On the other hand, as shown in Figure 9, the reflectance of the reflecting mirror of the comparative example changes significantly before and after autoclave sterilization. Specifically, before autoclave sterilization, the wavelength at which the reflectance of the reflecting mirror is 96% is 521 nm. On the other hand, after autoclave sterilization, the wavelength at which the reflectance of the reflecting mirror is 96% is 549 nm. Therefore, the wavelength at which the reflectance of the reflecting mirror is 96% changes significantly by 28 nm before and after autoclave sterilization. Therefore, the weather resistance of the comparative example is not sufficiently high.

[0075] An example of an application requiring high weather resistance, such as a difference in wavelength at which the reflectance of the reflecting mirror is 96% before and after autoclave sterilization, of 0 nm or more and 20 nm or less, is use in an endoscope. Since endoscopes are inserted directly into the human body, they must be sterilized in an autoclave. Therefore, the reflecting mirror of the present invention can be suitably used in endoscopes. However, the applications of the reflecting mirror of the present invention are not limited to those described above.

[0076] The reason why the reflectance and weather resistance of the reflecting mirror obtained by using the method for forming a film on a glass article according to the second embodiment can be increased is as follows.

[0077] In the second embodiment, as shown in FIG. 5(b), the first protective layer 7A, which is an aluminum oxide film, is formed on the reflective film 6, which is an Ag film, without using ion-assisted deposition or ion plating deposition. During this process, Al particles, Al oxide particles, and the like collide with the Ag film. Because ion-assisted deposition or ion plating deposition is not used in forming the first protective layer 7A, the collision energy is small. Therefore, excessive energy is prevented from being applied to the Ag film during the formation of the first protective layer 7A. This prevents crystal growth of Ag in the Ag film due to the formation of the first protective layer 7A. This prevents the flatness of the Ag film from being reduced. Therefore, the reflectivity of the reflecting mirror can be increased.

[0078] As shown in FIGS. 5(a) to 5(c) and Table 1, in the second embodiment, a first protective layer 7A, which is an aluminum oxide film, is laminated directly on a reflective film 6, which is an Ag film. A second protective layer 7B, which is a silicon oxide film, is laminated directly on the first protective layer 7A. The Ag film and the aluminum oxide film have high adhesion. The aluminum oxide film and the silicon oxide film also have high adhesion. This makes it difficult for moisture and air to enter the vicinity of the reflective film 6 on the reflecting mirror. This makes it possible to suppress reaction of the Ag film serving as the reflective film 6. Furthermore, moisture and air are unlikely to enter the aluminum oxide film. This makes it possible to improve the weather resistance of the reflecting mirror.

[0079] As in the second embodiment, when forming an Ag film as the reflective film 6, the temperature of the glass article 2 is preferably set to 100°C or less, and more preferably to 80°C or less. This effectively suppresses Ag crystal growth during Ag film formation. This effectively prevents the Ag film from becoming less flat. Therefore, the reflectance of the reflecting mirror can be effectively increased. Details of this are provided below.

[0080] The reflecting mirror 1 shown in Fig. 1 was produced using the method for forming a film on a glass article according to the second embodiment. At this time, the temperature of the glass article 2 was set to 50°C when forming an Ag film as the reflective film 6. On the other hand, a plurality of reflecting mirrors 1 were produced by changing the temperature of the glass article 2 when forming the Ag film. The reflectance of these reflecting mirrors 1 at a wavelength of 500 nm was compared.

[0081] In addition, the arithmetic mean roughness Ra of the surface of the second protective layer 7B serving as the first outermost layer was compared for these reflecting mirrors 1. The conditions for producing each reflecting mirror 1 were the same except for the temperature of the glass article 2 when the reflective film 6 was formed. The first outermost layer was laminated on the reflective film 6. Therefore, the trend of the arithmetic mean roughness Ra of the first outermost layer depends on the trend of the arithmetic mean roughness Ra of the reflective film 6. Therefore, indicating the trend of the arithmetic mean roughness Ra of the first outermost layer can be said to essentially indicate the trend of the arithmetic mean roughness Ra of the reflective film 6.

[0082] Furthermore, from the results of the above comparisons, the relationship between the reflectance of the reflecting mirror 1 at a wavelength of 500 nm and the arithmetic mean roughness Ra of the first outermost layer was derived.

[0083] Fig. 10 is a diagram showing the relationship between the temperature of the glass article when an Ag film is formed and the reflectance of the reflecting mirror at a wavelength of 500 nm. Fig. 11 is a diagram showing the relationship between the temperature of the glass article when an Ag film is formed and the arithmetic mean roughness Ra of the first outermost layer. Fig. 12 is a diagram showing the relationship between the reflectance of the reflecting mirror at a wavelength of 500 nm and the arithmetic mean roughness Ra of the first outermost layer.

[0084] 10, it can be seen that the lower the temperature of the glass article 2 when forming the Ag film, the higher the reflectance of the reflecting mirror 1 at a wavelength of 500 nm. When the temperature is set to 100° C. or lower, it can be seen that the reflectance of the reflecting mirror 1 at a wavelength of 500 nm is particularly high.

[0085] 11, it can be seen that the lower the temperature, the smaller the arithmetic mean roughness Ra of the first outermost layer of the reflecting mirror 1. This indicates that the lower the temperature of the glass article 2 when forming the Ag film, the smaller the arithmetic mean roughness Ra of the Ag film and the higher the flatness of the Ag film.

[0086] 12, the smaller the arithmetic mean roughness Ra of the first outermost layer of reflecting mirror 1, the higher the reflectance of reflecting mirror 1 at a wavelength of 500 nm. This indicates that the smaller the arithmetic mean roughness Ra of the Ag film and the higher the flatness of the Ag film, the higher the reflectance of reflecting mirror 1 at a wavelength of 500 nm.

[0087] A preferred configuration for the method of forming a film on a glass article according to the present invention will be described below. For convenience, the preferred configuration will be described as an example for manufacturing the reflecting mirror 1 of the first embodiment. It should be noted that the preferred configuration is not limited to the case of manufacturing the reflecting mirror 1.

[0088] It is preferable to form the Ag film as the reflective film 6 shown in FIG. 5(a) without using ion-assisted deposition or ion plating deposition. This effectively suppresses Ag crystal growth during Ag film formation. This effectively prevents the Ag film from becoming less flat. Therefore, the reflectance of the reflecting mirror 1 can be effectively increased.

[0089] The lower limit of the average deposition rate for depositing the reflective film 6 is preferably 1 nm / s or more, more preferably 3 nm / s or more, even more preferably 5 nm / s or more, and particularly preferably 8 nm / s or more. On the other hand, the upper limit of the average deposition rate is preferably 20 nm / s or less, more preferably 15 nm / s or less, and particularly preferably 10 nm / s or less.

[0090] By setting the average deposition rate to the above lower limit or higher, oxidation of Ag can be suppressed when depositing the Ag film as the reflective film 6. This allows the flatness of the reflective film 6 to be improved. Therefore, the reflectance of the reflecting mirror 1 can be further increased. By setting the average deposition rate to the above upper limit or lower, the energy of Ag particles colliding with the glass article 2 can be reduced, and crystal growth of Ag can be suppressed. At the same time, the deposition time can be shortened.

[0091] When forming the second protective layer 7B shown in Figure 5(c), it is preferable to use ion-assisted deposition or ion plating deposition. This can improve the adhesion of the second protective layer 7B to the first protective layer 7A. This can effectively improve the weather resistance of the reflecting mirror 1.

[0092] When a protective layer having three or more layers is provided, it is preferable to use ion-assisted deposition or ion plating deposition when depositing the layers other than the first protective layer 7A in the protective layer. This can improve the adhesion between the layers in the protective layer. This can effectively improve the weather resistance of the reflecting mirror.

[0093] 5(a) and the like, it is preferable to provide an adhesive layer 4 directly on the glass article 2 before forming the reflective film 6. This makes it difficult for the reflective film 6 to peel off from the glass article 2.

[0094] It is preferable that the adhesion layer 4 includes a silicon oxide film as the first adhesion layer 4A and an aluminum oxide film as the second adhesion layer 4B. The silicon oxide film has high adhesion to the glass article 2. The aluminum oxide film also has high adhesion to the Ag film. This makes it even more difficult for the reflective film 6 to peel off from the glass article 2. More specifically, even after the reflecting mirror 1 has been sterilized in an autoclave, the reflective film 6 is even more difficult to peel off from the glass article 2. This makes it possible to increase the reliability of the reflecting mirror 1.

[0095] When forming the first adhesive layer 4A, the temperature of the glass article 2 is preferably 100° C. or higher and 400° C. or lower, and more preferably 200° C. or higher and 300° C. or lower. This effectively increases the adhesion of the silicon oxide film serving as the first adhesive layer 4A to the glass article 2.

[0096] It is preferable to use ion-assisted deposition or ion plating deposition when forming the first adhesion layer 4A, which can effectively increase the adhesion of the silicon oxide film serving as the first adhesion layer 4A to the glass article 2.

[0097] In the following, the terms "first reflectance" and "second reflectance" may be used to indicate the reflectance of a reflecting mirror.

[0098] FIG. 13 is a schematic front cross-sectional view for explaining the first reflectance and the second reflectance.

[0099] Arrow A in FIG. 13 indicates the optical path when light is incident on reflecting mirror 1 from the first outermost layer side of multilayer film 3. The reflectance measured from the first outermost layer side of multilayer film 3 is the first reflectance. The first reflectance refers to the reflectance shown in FIGS. 6 to 9, etc. On the other hand, arrow B in FIG. 13 indicates the optical path when light is incident on reflecting mirror 1 from the second outermost layer side of multilayer film 3. The reflectance measured from the second outermost layer side of multilayer film 3 is the second reflectance.

[0100] When a reflecting mirror is manufactured using the method for forming a film on a glass article according to the present invention, not only the first reflectance but also the second reflectance can be increased, as will be described in detail below.

[0101] The reflecting mirror 1 shown in FIG. 1 was produced using the method for forming a film on a glass article according to the second embodiment. In this reflecting mirror 1, the arithmetic mean roughness Ra of the second protective layer 7B serving as the first outermost layer was 1 nm. On the other hand, the reflecting mirror 1 was produced in the same manner as in the second embodiment, except that the temperature of the glass article 2 was increased to more than 100°C when forming the Ag film serving as the reflective film 6. In this reflecting mirror 1, the arithmetic mean roughness Ra of the first outermost layer was 7 nm. The first reflectance and second reflectance of these reflecting mirrors 1 were measured. The first reflectance and second reflectance were measured using an automatic spectrophotometer (manufactured by Hitachi, Ltd., model number "UH-4150") using an integrating sphere, with the incident angle of unpolarized light set to 45°.

[0102] Fig. 14 is a diagram showing the first reflectance and the second reflectance of a reflecting mirror whose first outermost layer has an arithmetic mean roughness Ra of 1 nm, and Fig. 15 is a diagram showing the first reflectance and the second reflectance of a reflecting mirror whose first outermost layer has an arithmetic mean roughness Ra of 7 nm.

[0103] As shown in Fig. 14, in a reflecting mirror 1 in which the arithmetic mean roughness Ra of the first outermost layer is 1 nm, both the first reflectance and the second reflectance are high. Specifically, the first reflectance is 96% or more in the wavelength range of 418 nm or more and 1000 nm or less. The second reflectance is 96% or more in the wavelength range of 400 nm or more and 1000 nm or less. In this way, both the first reflectance and the second reflectance can be made high, at 96% or more, in a wide wavelength range of 500 nm or more.

[0104] 15, in a reflecting mirror 1 in which the arithmetic mean roughness Ra of the first outermost layer is 7 nm, the first reflectance is 96% or more in the wavelength range of 533 nm or more and 1000 nm or less, and the second reflectance is 96% or more in the wavelength range of 400 nm or more and 1000 nm or less.

[0105] 14 and 15, the arithmetic mean roughness Ra of the first outermost layer has a large effect on the first reflectance of the reflecting mirror 1. Specifically, the smaller the arithmetic mean roughness Ra of the first outermost layer, the larger the first reflectance in a wider wavelength range. On the other hand, the arithmetic mean roughness Ra of the first outermost layer has a small effect on the second reflectance of the reflecting mirror 1.

[0106] In the case shown in Figure 14, both the first reflectance and the second reflectance of reflecting mirror 1 are 96% or more in the wavelength range of 418 nm or more and 1000 nm or less. Therefore, in any wavelength range of 500 nm or more in the range of 418 nm or more and 1000 nm or less, both the first reflectance and the second reflectance are 96% or more. In this way, it is preferable that both the first reflectance and the second reflectance are 96% or more in a wavelength range of 500 nm or less. In this case, the applications of reflecting mirror 1 can be suitably widened.

[0107] The reflectances shown in Figures 6 to 8 correspond to the first reflectance. As described above, it is preferable that the difference in wavelength at which the first reflectance is 96% before being placed in an environment with a temperature of 135°C and a humidity of 94% and after being placed in that environment for 50 hours be 0 nm or more and 20 nm or less. Similarly, it is preferable that the difference in wavelength at which the second reflectance is 96% before being placed in an environment with a temperature of 135°C and a humidity of 94% and after being placed in that environment for 50 hours be 0 nm or more and 20 nm or less. In this case, the weather resistance of the reflecting mirror is particularly high.

[0108] (Endoscopy) The endoscope according to the present invention includes a reflecting mirror according to the present invention. Therefore, the reflecting mirror in the endoscope has high reflectivity and weather resistance. In particular, since endoscopes are inserted directly into the human body, they must be sterilized in an autoclave. In contrast, the reflecting mirror in the endoscope has weather resistance that allows it to withstand autoclave sterilization. Therefore, deterioration of visibility in the endoscope can be suppressed. [Explanation of symbols]

[0109] 1...Reflector 2. Glass items 2a, 2b...first and second principal surfaces 3...Multilayer film 4...Adhesion layer 4A, 4B...First and second adhesive layers 5…Reflective layer 6...Reflective film 7…Protective layer 7A, 7B...First and second protective layers 11...Reflector 17...Protective layer 17C, 17D...Third and fourth protective layers 21...Reflector 27…Protective layer 27E…5th layer of protection

Claims

1. a reflective film forming step of forming a reflective film, which is an Ag film, on the glass article; a first protective layer forming step of forming a first protective layer, which is an aluminum oxide film, directly on the reflective film without using ion-assisted deposition or ion plating deposition; a second protective layer forming step of forming a second protective layer, which is a silicon oxide film, directly on the first protective layer; A method for forming a film on a glass article, comprising:

2. 2. The method for forming a film on a glass article according to claim 1, wherein the second protective layer forming step uses ion-assisted deposition or ion-plating deposition.

3. 2. The method for forming a film on a glass article according to claim 1, wherein in the reflective film forming step, an average film forming rate for forming the reflective film is 1 nm / s or more and 20 nm / s or less.

4. 2. The method for forming a film on a glass article according to claim 1, wherein the temperature of the glass article is set to 100° C. or less in the reflective film forming step, and ion-assisted deposition and ion plating deposition are not used.

5. The method for forming a film on a glass article according to any one of claims 1 to 4, further comprising a first adhesion layer formation step of forming a first adhesion layer which is a silicon oxide film on the glass article, the temperature of which has been adjusted to 100°C or more and 400°C or less, by ion-assisted deposition or ion plating deposition, before the reflective film formation step.

6. 6. The method for forming a film on a glass article according to claim 5, further comprising a second adhesion layer forming step of forming a second adhesion layer, which is an aluminum oxide film, on the first adhesion layer between the first adhesion layer forming step and the reflective film forming step.

7. a glass article having a first main surface and a second main surface facing each other; A multilayer film including a reflective functional layer that is a laminate provided on the first main surface of the glass article and has a function of reflecting light; Equipped with A reflecting mirror, wherein the reflective functional layer includes a reflective film which is an Ag film located closest to the glass article, a first protective layer which is an aluminum oxide film laminated directly on the reflective film, and a second protective layer which is a silicon oxide film laminated directly on the first protective layer.

8. The multilayer film further includes a first adhesion layer that is a silicon oxide film and is laminated directly on the first main surface of the glass article, and a second adhesion layer that is an aluminum oxide film and is laminated directly on the first adhesion layer, 8. The reflecting mirror according to claim 7, wherein the reflective function layer is directly laminated on the second adhesive layer.

9. 9. The reflecting mirror according to claim 7, wherein the difference in wavelength at which the reflectance is 96% is 0 nm or more and 20 nm or less before and after being placed in an environment of a temperature of 135°C and a humidity of 94% for 50 hours.

10. In the multilayer film, the layer farthest from the glass article is a first outermost layer, and the layer closest to the glass article is a second outermost layer; 9. The reflecting mirror according to claim 7, wherein when a reflectance measured from the first outermost layer side of the multilayer film is defined as a first reflectance and a reflectance measured from the second outermost layer side is defined as a second reflectance, both the first reflectance and the second reflectance are 96% or more in a wavelength range having a width of 500 nm.

11. 11. The reflecting mirror according to claim 10, wherein a difference in wavelength at which the first reflectance is 96% is 0 nm or more and 20 nm or less, and a difference in wavelength at which the second reflectance is 96% is 0 nm or more and 20 nm or less, before and after being placed in an environment of a temperature of 135°C and a humidity of 94% for 50 hours.

12. In the multilayer film, the layer farthest from the glass article is a first outermost layer, and the layer closest to the glass article is a second outermost layer; 9. The reflecting mirror according to claim 7, wherein the first outermost layer has an arithmetic mean roughness Ra of 5 nm or less.

13. An endoscope comprising the reflecting mirror according to claim 7 or 8.

Images