Method for producing substrate with functional film and chalcogenide glass substrate with antireflection film

Abstract

To provide a method for producing a substrate with functional film capable of improving the reliability of the substrate with functional film.SOLUTION: A method for producing a substrate with functional film according to the present invention is the method for producing a substrate 1 with functional film in which a vacuum vapor deposition apparatus is used to form on a substrate 2 a functional film 3 having a Ge film (high-refractive-index film 5) containing Ge as a main component. The method includes the steps of: preparing the substrate 2; placing the substrate 2 in the vacuum vapor deposition apparatus; and forming the Ge film on the substrate 2. During the step of forming the Ge film on the substrate 2, oxygen is introduced into the vacuum vapor deposition apparatus.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a substrate with a functional film and a chalcogenide glass substrate with an anti-reflection film. [Background technology]

[0002] In recent years, optical devices that utilize infrared rays have been widely used. For example, in-vehicle night vision and security systems are equipped with infrared sensors that are used to detect living organisms at night. Infrared sensors detect infrared rays with wavelengths of approximately 8 μm to 14 μm emitted from living organisms, so optical components such as lenses and filters that transmit infrared rays in this wavelength range are provided in front of the sensor unit.

[0003] As an example of such an optical component, Patent Document 1 below discloses a film-coated substrate in which a multilayer film is provided on a substrate. In Patent Document 1, the multilayer film has an adhesive layer, a high-refractive index film, a low-refractive index film, and an outermost layer. The high-refractive index film is made of Ge. The low-refractive index film is made of at least one of YF3 and YbF3. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-020448 Summary of the Invention [Problem to be solved by the invention]

[0005] The present inventors have found that weather resistance may be easily reduced when the high refractive index film is made of Ge and the low refractive index film is made of YF3, as described in Patent Document 1. When the weather resistance of the multilayer film is low, the function of the film-coated substrate is easily deteriorated over long-term use, and the reliability of the film-coated substrate decreases.

[0006] An object of the present invention is to provide a method for manufacturing a functional film-coated substrate that can increase the reliability of the functional film-coated substrate, and to provide a chalcogenide glass substrate with an anti-reflection film that can increase the reliability. [Means for solving the problem]

[0007] A method for manufacturing a functional film-coated substrate according to aspect 1 of the present invention is a method for manufacturing a functional film-coated substrate in which a functional film having a Ge film containing Ge as a main component is provided on a substrate by using a vacuum evaporation deposition apparatus, and includes the steps of preparing the substrate, placing the substrate in the vacuum evaporation deposition apparatus, and depositing the Ge film on the substrate, and is characterized in that oxygen is introduced into the vacuum evaporation deposition apparatus during the step of depositing the Ge film on the substrate.

[0008] In the method for producing a functional film-formed substrate of the second aspect, in the first aspect, in the step of forming the Ge film on the substrate, the pressure in the vacuum evaporation film-forming apparatus is 0.8×10 -3 Pa or higher, 7×10 -3 It is preferable that the pressure is 0.01 Pa or less.

[0009] In the method for producing a functional film-formed substrate of aspect 3, in aspect 1 or 2, it is preferable that the introduction of oxygen into the vacuum evaporation deposition apparatus is stopped after the step of forming the Ge film on the substrate.

[0010] A method for manufacturing a functional film-formed substrate according to aspect 4 is a method for manufacturing a functional film-formed substrate according to aspect 3, in which the vacuum evaporation deposition apparatus is used to form the functional film on the substrate, the functional film including the Ge film and a YF3 film containing YF3 as a main component, and the method further includes a step of forming the YF3 film on the substrate, wherein the step of forming the YF3 film on the substrate is performed when the pressure inside the vacuum evaporation deposition apparatus is 0.7×10 -3 It is preferable to carry out the test after the pressure drops to 0.2 Pa or less.

[0011] In the method for manufacturing a substrate with a functional film of aspect 5, in any one of aspects 1 to 4, the vacuum evaporation deposition apparatus is used to form a functional film on the substrate, the functional film comprising the Ge film and a YF3 film containing YF3 as a main component, and the method for manufacturing a substrate with a functional film of aspect 5 further comprises a step of forming the YF3 film on the substrate, and the vacuum evaporation deposition apparatus preferably has a container for placing an evaporation material, and in the step of forming the YF3 film on the substrate, an indirect heating method is used in which the evaporation material consisting of YF3 is evaporated by heating the container in which the evaporation material is placed.

[0012] In the method for manufacturing a functional film-coated substrate of aspect 6, in any one of aspects 1 to 5, in the step of forming the Ge film on the substrate, it is preferable to use a direct heating method in which a vapor deposition material consisting of Ge is evaporated by directly heating the vapor deposition material.

[0013] In the method for producing a functional film-coated substrate of Aspect 7, in any one of Aspects 1 to 6, the substrate is preferably a chalcogenide glass substrate.

[0014] In the method for producing a functional film-coated substrate of aspect 8, in any one of aspects 1 to 7, the functional film is preferably an anti-reflection film.

[0015] A chalcogenide glass substrate with an anti-reflective coating according to aspect 9 of the present invention comprises a chalcogenide glass substrate and an anti-reflective coating provided on the chalcogenide glass substrate, wherein the anti-reflective coating comprises a Ge film having a relatively high refractive index and containing Ge as its main component, and a YF3 film having a relatively low refractive index and containing YF3 as its main component, and wherein the concentration of oxygen contained in the Ge film is higher than the concentration of oxygen contained in the YF3 film.

[0016] In the chalcogenide glass substrate with an antireflection film of embodiment 10, in embodiment 9, the center wavelength of the light to be transmitted is preferably 8 μm or more and 14 μm or less. [Effects of the Invention]

[0017] According to the method for manufacturing a functional film-coated substrate of the present invention, the reliability of the functional film-coated substrate can be increased. According to the chalcogenide glass substrate with an anti-reflection film of the present invention, the reliability can be increased. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic front cross-sectional view of a functional film-attached substrate according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a schematic front cross-sectional view of a functional film-attached substrate according to a second embodiment of the present invention. [Figure 3] FIG. 3 is a schematic diagram of a vacuum evaporation film-forming apparatus used in a method for producing a functional film-formed substrate according to a third embodiment of the present invention. [Figure 4] FIG. 4 is a schematic diagram showing a part of a vacuum evaporation film-forming apparatus when forming a film using the direct heating method. [Figure 5] FIG. 5 is a schematic diagram showing a part of a vacuum evaporation film-forming apparatus when forming a film using the indirect heating method. [Figure 6] FIG. 6 is a schematic perspective view for explaining a method for measuring the amount of warpage of a film-coated substrate. [Figure 7] FIG. 7 is a diagram showing the amount of warpage in each of the film-coated substrates obtained by the step of forming a Ge film in the third embodiment of the present invention and the comparative example. [Figure 8] FIG. 8 is a diagram showing the infrared transmittance of the functional film-coated substrates obtained by the manufacturing method of the third embodiment of the present invention and the first reference example. [Figure 9]FIG. 9 shows the relationship between the position in the thickness direction and the oxygen concentration of a Ge film formed when the pressure in the chamber of a vacuum evaporation deposition apparatus was set to 1×10 Pa or more, 3×10 Pa or less, and 0.7×10 Pa. [Figure 10] FIG. 10 is a diagram showing the amount of warpage in each of the film-coated substrates obtained by the step of forming a YF3 film in the third embodiment of the present invention and the second reference example. [Figure 11] FIG. 11 is a photograph of the film-coated substrate obtained by the step of forming a YF3 film in the second reference example after the film-coated substrate was placed in a high-temperature and high-humidity environment. [Figure 12] FIG. 12 is a photograph of the film-coated substrate obtained by the step of forming a YF3 film in the third embodiment of the present invention after the film-coated substrate was placed in a high-temperature and high-humidity environment. [Figure 13] Figure 13 is a diagram showing the infrared transmittance of a functional film-coated substrate obtained by the manufacturing method of the third embodiment of the present invention before and after being placed in a high-temperature, high-humidity environment. DETAILED DESCRIPTION OF THE INVENTION

[0019] 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.

[0020] (Substrate with functional film) (First embodiment) FIG. 1 is a schematic front cross-sectional view of a functional film-attached substrate according to a first embodiment of the present invention.

[0021] The functional film-coated substrate 1 of this embodiment is a chalcogenide glass substrate with an anti-reflection film. Specifically, the functional film-coated substrate 1 includes a substrate 2 and a functional film 3. In this embodiment, the substrate 2 is a chalcogenide glass substrate. A chalcogenide glass substrate is a substrate made of chalcogenide glass. However, the chalcogenide glass substrate may contain a trace amount of impurities. The functional film 3 is an anti-reflection film.

[0022] The substrate 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 functional film 3 is provided on the first main surface 2a of the substrate 2. In this embodiment, the functional film 3 is not provided on the second main surface 2b. Note that the functional film 3 may be provided on both the first main surface 2a and the second main surface 2b.

[0023] In the present invention, various materials can be used for the substrate 2 depending on the required characteristics. In particular, when the functional film-coated substrate 1 is used as an infrared-transmitting lens or the like, it is preferable that the functional film-coated substrate 1 has high infrared transmittance. Specifically, the average infrared transmittance of the substrate 2 at a thickness of 2 mm in the wavelength range of 8 μm or more and 14 μm or less is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. In this case, the functional film-coated substrate 1 can be particularly suitably used for applications that transmit light with a central wavelength of 8 μm or more and 14 μm or less.

[0024] In this embodiment, chalcogenide glass, which is infrared-transmitting glass, is used as the material for the substrate 2. However, for example, Ge or ZnS may also be used as the material for the substrate 2. In this case, the functional film-coated substrate 1 can also be suitably used as an infrared-transmitting lens or the like.

[0025] The shape of the substrate 2 is not particularly limited, and examples thereof include a disk shape, a rectangular plate shape, a lens shape, a prism shape, etc. The rectangular plate shape refers to a plate shape in which the main surface has a rectangular shape.

[0026] The thickness of the substrate 2 is not particularly limited and can be set appropriately depending on the infrared transmittance, etc. The thickness of the substrate 2 can be, for example, about 0.5 mm to 3 mm.

[0027] The functional film 3 is a multilayer film formed by laminating an adhesive film 4, a high refractive index film 5, a low refractive index film 6, an intermediate refractive index film 7, and an outermost film 8. The adhesive film 4 is the film located closest to the substrate 2 among the functional film 3. The outermost film 8 is the film located outermost among the functional film 3 when the substrate 2 side is considered to be the inside. The functional film 3 includes one adhesive film 4 and one outermost film 8.

[0028] The high refractive index film 5 is a film with a relatively high refractive index. The low refractive index film 6 is a film with a relatively low refractive index. The refractive index of the high refractive index film 5 is higher than that of the low refractive index film 6. The intermediate refractive index film 7 refers to a film whose refractive index is between the refractive index of the high refractive index film 5 and the refractive index of the low refractive index film 6. The functional film 3 includes a plurality of high refractive index films 5, a plurality of low refractive index films 6, and a plurality of intermediate refractive index films 7.

[0029] In this embodiment, the adhesion film 4 contains Si as a main component. In this specification, the main component of a member such as a film refers to a component that accounts for more than 50% by weight of the member. The main component of the adhesion film 4 is not limited to the above. For example, the main component of the adhesion film 4 may be the same as the main component of the high refractive index film 5, the low refractive index film 6, or the intermediate refractive index film 7.

[0030] The high refractive index film 5 is a Ge film containing Ge as a main component, and the low refractive index film 6 is a YF3 film containing YF3 as a main component. In these cases, the infrared transmittance of the functional film-coated substrate 1 can be increased.

[0031] The intermediate refractive index film 7 is a ZnS film containing ZnS as a main component. In the example shown in Fig. 1, the intermediate refractive index film 7 is provided between the high refractive index film 5 and the low refractive index film 6. The intermediate refractive index film 7 may also be provided between the high refractive index films 5 or between the low refractive index films 6.

[0032] The main component of the intermediate refractive index film 7 is not limited to ZnS. Alternatively, the intermediate refractive index film 7 may not be provided. In this case, for example, it is sufficient that the high refractive index films 5 and the low refractive index films 6 are alternately laminated.

[0033] The outermost film 8 contains ZnS as a main component. However, the main component of the outermost film 8 is not limited to the above. For example, the main component of the outermost film 8 may be the same as the main component of the high refractive index film 5 or the low refractive index film 6.

[0034] In the present invention, the functional film 3 may have at least a Ge film as the high refractive index film 5 and a YF3 film as the low refractive index film 6. The functional film 3 may have a configuration in which Ge films and YF3 films are alternately stacked.

[0035] The features of this embodiment are that the substrate 2 is a chalcogenide glass substrate, the functional film 3 is an anti-reflection film, and the concentration of oxygen contained in the Ge film, which is the high refractive index film 5, is higher than the concentration of oxygen contained in the YF3 film, which is the low refractive index film 6. This makes it possible to increase the infrared transmittance of the functional film-coated substrate 1 and to increase the reliability of the functional film-coated substrate 1. This will be explained below.

[0036] The lower the oxygen concentration contained in the Ge film, the higher the infrared transmittance of the Ge film. Therefore, conventionally, Ge films have been formed so that the oxygen concentration contained in the Ge film is low. Specifically, the Ge film is formed by, for example, a vacuum evaporation method. In this case, the Ge film is formed in a chamber of a vacuum evaporation film-forming apparatus. The pressure in the chamber is set to 0.7×10 -3 By setting the pressure to be equal to or less than Pa, the concentration of oxygen contained in the Ge film is reduced, thereby increasing the infrared transmittance of the Ge film.

[0037] However, the present inventors have found that when the concentration of oxygen contained in the Ge film is low, the film stress of the Ge film is higher than when the concentration of oxygen contained in the Ge film is high. When the film stress of the Ge film contained in the functional film 3 is high, the functional film 3 is more likely to peel off. Furthermore, the present inventors have found that the weather resistance of the functional film 3 decreases even if the functional film 3 is not completely peeled off from the substrate 2 or even if complete peeling does not occur between layers of the functional film 3.

[0038] In this embodiment, the concentration of oxygen contained in the Ge film, which is the high-refractive-index film 5, is higher than the concentration of oxygen contained in the YF3 film, which is the low-refractive-index film 6. This reduces the film stress of the Ge film, making it less likely that the functional film 3 will peel off from the substrate 2 or between layers of the functional film 3. This increases the weather resistance of the functional film 3, and increases the reliability of the functional film-coated substrate 1.

[0039] Furthermore, even if the oxygen concentration in the Ge film is higher than that in the YF3 film, the inventors' investigations have revealed that the infrared transmittance of the Ge film is sufficiently high. In addition, the infrared transmittance of the YF3 film is also high. Therefore, in this embodiment, the infrared transmittance of the functional film-coated substrate 1 can be increased, and the reliability of the functional film-coated substrate 1 can be improved. The infrared transmittance of the functional film-coated substrate 1 will be described in detail below.

[0040] The oxygen concentration in the Ge film is 3.8×10 19 It is preferable that the oxygen concentration is higher than 1.1×10 atoms / cc. In this case, it is easy to reduce the film stress of the Ge film. 20 atoms / cc or more, 4.6×10 20 atoms / cc or less is more preferable, and 1.8×10 20It is more preferable that the concentration is within ±40% of atoms / cc. This makes it possible to more reliably reduce the film stress of the Ge film and more reliably increase the infrared transmittance of the Ge film. Therefore, it is possible to more reliably and effectively increase the reliability of the functional film-coated substrate 1 and more reliably increase the infrared transmittance of the functional film-coated substrate 1.

[0041] 1 is not particularly limited, but is preferably 10 nm or more, more preferably 30 nm or more. On the other hand, the thickness of the adhesion film 4 is preferably 100 nm or less, more preferably 60 nm or less.

[0042] The thickness of each layer of the high-refractive-index film 5 is not particularly limited, but is preferably 40 nm or more, and more preferably 60 nm or more. On the other hand, the thickness of each layer of the high-refractive-index film 5 is preferably 1000 nm or less, more preferably 850 nm or less, even more preferably 650 nm or less, even more preferably 400 nm or less, particularly preferably 150 nm or less, and most preferably 100 nm or less. By setting the thickness of the Ge film as the high-refractive-index film 5 within this range, infrared absorption by the Ge film can be suppressed, and the decrease in infrared transmittance can be further suppressed. Additionally, the production cost of the functional film-coated substrate 1 can be further reduced.

[0043] When the total thickness of the high-refractive-index films 5 is the sum of the thicknesses of all the high-refractive-index films 5 in the functional film 3, the total thickness of the high-refractive-index films 5 is not particularly limited, but is preferably 100 nm or more, and more preferably 150 nm or more. On the other hand, the total thickness of the high-refractive-index films 5 is preferably 1300 nm or less, more preferably 1100 nm or less, even more preferably 900 nm or less, particularly preferably 700 nm or less, and most preferably 500 nm or less. By setting the total thickness of the Ge films as the high-refractive-index films 5 within this range, infrared absorption by the Ge films can be suppressed, further suppressing a decrease in infrared transmittance. Additionally, the production cost of the functional film-coated substrate 1 can be further reduced.

[0044] The thickness of each layer of the low refractive index film 6 is not particularly limited, but is preferably 50 nm or more, more preferably 100 nm or more. On the other hand, the thickness of each layer of the low refractive index film 6 is preferably 1600 nm or less, more preferably 1300 nm or less.

[0045] The thickness of each layer of the intermediate refractive index film 7 is not particularly limited, but is preferably 50 nm or more, more preferably 100 nm or more, and is preferably 1600 nm or less, more preferably 1300 nm or less.

[0046] The total thickness of the high refractive index film 5, low refractive index film 6, and intermediate refractive index film 7 located between the adhesive film 4 and the outermost film 8 is not particularly limited, but is preferably 1000 nm or more, more preferably 1700 nm or more. On the other hand, the total thickness is preferably 4000 nm or less, more preferably 3500 nm or less.

[0047] The number of layers of all the films constituting the functional film 3 is preferably 3 or more, and more preferably 5 or more. On the other hand, the number of layers of all the films constituting the functional film 3 is preferably 20 or less, and more preferably 15 or less. Note that, when each layer is formed by vacuum deposition, the number of layers referred to here is defined as one film consisting of consecutive layers formed using the same deposition material. For example, when a Ge film is formed on a Ge film formed using a deposition material made of Ge, and another Ge film is formed on the Ge film using another deposition material made of Ge, this is considered to be one Ge film.

[0048] The thickness of the outermost film 8 is not particularly limited, but is preferably 10 nm or more, and more preferably 30 nm or more. On the other hand, the thickness of the outermost film 8 is preferably 300 nm or less, and more preferably 250 nm or less.

[0049] The adhesive film 4 and the outermost film 8 preferably contain Si or Y2O3 as a main component. This can increase the infrared transmittance of the adhesive film 4 and the outermost film 8. It can also increase the adhesion of the adhesive film 4 and the outermost film 8 to the high refractive index film 5, the low refractive index film 6, or the intermediate refractive index film 7. In addition, it can also increase the adhesion of the adhesive film 4 to the substrate 2. Alternatively, the adhesive film 4 and the outermost film 8 may contain, for example, Ge, YF3, or YbF3 as a main component.

[0050] In this embodiment, the substrate 2 is a chalcogenide glass substrate. The components of the chalcogenide glass will be described in detail below.

[0051] Chalcogenide glass contains chalcogen elements (Te, S, and Se) as essential components. The chalcogen elements form the glass skeleton and increase infrared transmittance. The content of the chalcogen elements (total amount of Te, S, and Se) is preferably 20% to 99%, more preferably 40% to 95%, even more preferably 50% to 85%, particularly preferably 60% to 85%, and most preferably 70% to 80% by mole. If the content of the chalcogen elements is too low, the raw materials for the chalcogenide glass are difficult to vitrify. If the content of the chalcogen elements is too high, evaporation of the glass components is likely to occur when the raw materials for the chalcogenide glass are melted, which can easily cause striae.

[0052] The chalcogenide glass preferably contains the chalcogen element Te. Te is a component that forms the glass skeleton and enhances infrared transmittance. The Te content, in mole percent, is preferably 20% to 99%, more preferably 40% to 95%, even more preferably 50% to 85%, particularly preferably 60% to 85%, and most preferably 70% to 80%. If the Te content is too low, the raw materials for the chalcogenide glass may be difficult to vitrify, and the infrared transmittance may be easily reduced. On the other hand, if the Te content is too high, the thermal stability of the glass may be easily reduced, and Te-based crystals may be easily precipitated. Note that the other chalcogen elements Se and S are more difficult to improve infrared transmittance than Te, and may shorten the infrared transmittance threshold wavelength.

[0053] In addition to the above components, the chalcogenide glass may contain the following components.

[0054] Ge is a component that broadens the vitrification range and improves the thermal stability of glass without reducing infrared transmittance. The Ge content, in mole percent, is preferably 0% to 40%, more preferably 1% to 35%, even more preferably 5% to 30%, particularly preferably 7% to 25%, and most preferably 10% to 20%. If the Ge content is too high, Ge-based crystals may be more likely to precipitate, which tends to increase the cost of raw materials.

[0055] Ga is a component that broadens the vitrification range and improves the thermal stability of glass without reducing infrared transmittance. The Ga content is preferably 0% to 30%, more preferably 1% to 30%, even more preferably 3% to 25%, particularly preferably 4% to 20%, and most preferably 5% to 15%, in mole percent. If the Ga content is too high, Ga-based crystals may be more likely to precipitate, which tends to increase the cost of raw materials.

[0056] Ag is a component that broadens the vitrification range and improves the thermal stability of glass. The Ag content is preferably 0% to 20%, more preferably 1% to 10%, in mole percent. If the Ag content is too high, it may be difficult to vitrify the raw material for chalcogenide glass.

[0057] Al is a component that broadens the vitrification range and improves the thermal stability of glass. The Al content is preferably 0% to 20%, and more preferably 0% to 10%, in mole percent. If the Al content is too high, it may be difficult to vitrify the raw material for chalcogenide glass.

[0058] Sn is a component that broadens the vitrification range and improves the thermal stability of glass. The Sn content is preferably 0% to 20%, and more preferably 0% to 10%, in mole percent. If the Sn content is too high, it may be difficult to vitrify the raw material of the chalcogenide glass.

[0059] In this embodiment, the functional film 3 is an anti-reflection film. The functional film-coated substrate 1 is a chalcogenide glass substrate with an anti-reflection film. A chalcogenide glass substrate with an anti-reflection film is preferably used for an infrared-transmitting lens. In particular, a chalcogenide glass substrate with an anti-reflection film is more preferably used for a night-vision camera lens for detecting people. Note that the functional film 3 in the present invention is not limited to an anti-reflection film. A first modified example and a second modified example of the first embodiment, in which the functional film 3 is other than an anti-reflection film, are shown below.

[0060] (First Modification) In the first modification, the functional film 3 is a reflective film. Such a reflective film can be produced, for example, by adjusting the film thickness and number of layers of the high refractive index film 5, low refractive index film 6, and intermediate refractive index film 7 that constitute the functional film 3. When the functional film 3 is a reflective film, the functional film-coated substrate 1 can be suitably used as a reflective mirror or the like. In this case, a material with low infrared transmittance may be used as the material for the substrate 2. Specifically, for example, borosilicate glass or quartz glass may be used as the material for the substrate 2.

[0061] (Second Modification) In the second modification, the functional film 3 is an optical filter film. Such an optical filter film can be produced, for example, by adjusting the film thickness and number of layers of the high refractive index film 5, low refractive index film 6, and intermediate refractive index film 7 that constitute the functional film 3. When the functional film 3 is an optical filter film, the functional film-coated substrate 1 is suitably used, for example, as an optical filter that can selectively transmit infrared light having a center wavelength of 8 μm or more and 14 μm or less.

[0062] (Second embodiment) FIG. 2 is a schematic front cross-sectional view of a functional film-attached substrate according to the second embodiment.

[0063] The functional film-coated substrate 11 of this embodiment is a chalcogenide glass substrate with an anti-reflection film, as in the first embodiment. That is, the substrate 2 is a chalcogenide glass substrate. The functional film 13 is an anti-reflection film. However, this embodiment differs from the first embodiment in that the functional film 13 does not have an adhesive film containing Si as a main component, an outermost film containing ZnS as a main component, or an intermediate refractive index film. In this embodiment, the functional film 13 is configured by alternately stacking high refractive index films 5 and low refractive index films 6. The high refractive index film 5 is a Ge film. The low refractive index film 6 is a YF3 film.

[0064] In the functional film 13, of the high refractive index film 5 and the low refractive index film 6, the high refractive index film 5 is located closest to the substrate 2. Of the high refractive index film 5 and the low refractive index film 6, the low refractive index film 6 may be located closest to the substrate 2. On the other hand, when the substrate 2 side is considered to be the inside, of the high refractive index film 5 and the low refractive index film 6, the low refractive index film 6 is located closest to the outside. Of the high refractive index film 5 and the low refractive index film 6, the high refractive index film 5 may be located closest to the outside.

[0065] In this embodiment, as in the first embodiment, the substrate 2 is a chalcogenide glass substrate, the functional film 13 is an anti-reflection film, and the concentration of oxygen contained in the Ge film that is the high refractive index film 5 is higher than the concentration of oxygen contained in the YF3 film that is the low refractive index film 6. This makes it possible to increase the infrared transmittance of the functional film-coated substrate 11 and also to increase the reliability of the functional film-coated substrate 11.

[0066] In the functional film 13, when the total thickness of the low refractive index films 6 is tL, the total thickness of the high refractive index films 5 is tH, and the ratio of the total thickness tL to the total thickness tH is tL / tH, the ratio tL / tH is preferably 2.2 or more, more preferably 5 or more, even more preferably 7 or more, and particularly preferably 9 or more. On the other hand, the ratio tL / tH is preferably 15 or less, more preferably 13 or less, even more preferably 10 or less, and particularly preferably 9.5 or less. When the ratio tL / tH is within the above range, the infrared transmittance of the functional film-coated substrate 11 can be effectively increased.

[0067] (Method of manufacturing a substrate with a functional film) (Third embodiment) An example of a method for manufacturing the functional film-coated substrate 1 of the first embodiment will be described below. This manufacturing method is a method for manufacturing a functional film-coated substrate according to the third embodiment of the present invention.

[0068] First, the substrate 2 shown in FIG. 1 is prepared. Next, a functional film 3 is provided on the first main surface 2a of the substrate 2. The functional film 3 can be provided by laminating an adhesive film 4, a high refractive index film 5, a low refractive index film 6, a medium refractive index film 7, and an outermost film 8 on the first main surface 2a of the substrate 2. In this embodiment, each film of the functional film 3 is formed by vacuum deposition. This results in a functional film-coated substrate 1. The functional film 3 may be provided on both the first main surface 2a and the second main surface 2b of the substrate 2.

[0069] A method for forming a Ge film as the high refractive index film 5 and a YF3 film as the low refractive index film 6 by vacuum deposition will be described in more detail below.

[0070] FIG. 3 is a schematic diagram of a vacuum evaporation film-forming apparatus used in a method for producing a functional film-formed substrate according to a third embodiment of the present invention.

[0071] The vacuum evaporation film-forming apparatus 20 includes a chamber 21, a container 23 for placing an evaporation material 22, an electron beam irradiation device 24, a shutter 25, a substrate dome 26 for placing a substrate 2, a gas inlet 27, a heater 28, a film thickness meter 29, and a vacuum pump. The container 23, the electron beam irradiation device 24, the shutter 25, the substrate dome 26, the heater 28, and the film thickness meter 29 are arranged inside the chamber 21. The gas inlet 27 and the vacuum pump are connected to the chamber 21. However, the vacuum evaporation film-forming apparatus 20 shown in FIG. 3 is just an example, and the vacuum evaporation film-forming apparatus for forming a Ge film and a YF3 film is not limited to the above.

[0072] When a Ge film is formed, the deposition material 22 is made of Ge. On the other hand, when a YF3 film is formed, the deposition material 22 is made of YF3. The electron beam irradiation device 24 irradiates the deposition material 22 with, for example, a schematic illustrated electron beam B in order to heat and evaporate the deposition material 22 in the container 23. Note that by rotating a shutter 25, the deposition material 22 to be deposited on the substrate 2 placed on the substrate dome 26 is selected.

[0073] During film formation, the pressure inside chamber 21 is reduced by a vacuum pump, as schematically indicated by arrow P. Here, gas inlet 27 is an inlet for introducing oxygen, an inert gas, etc. into chamber 21. During film formation, oxygen, an inert gas, etc. is introduced into chamber 21 from gas inlet 27 as needed, as schematically indicated by arrow O. However, even when oxygen, an inert gas, etc. is being introduced into chamber 21, the pressure inside chamber 21 is continuously reduced by the vacuum pump.

[0074] The heater 28 is used to adjust the temperature of the substrate 2. The film thickness meter 29 measures the film thickness of the deposited film. The film thickness meter 29 is electrically connected to the outside of the chamber 21.

[0075] In this embodiment, the prepared substrate 2 is placed in a substrate dome 26 in a chamber 21 of a vacuum evaporation film-forming apparatus 20. A plurality of substrates 2 may be placed on the substrate dome 26. Next, a functional film 3 is provided on the first main surface 2a of the substrate 2. This process includes a step of forming a Ge film on the first main surface 2a of the substrate 2 and a step of forming a YF3 film on the first main surface 2a of the substrate 2. However, in this embodiment, the process of providing the functional film 3 on the first main surface 2a also includes a step of forming an adhesion film 4 on the first main surface 2a, a step of forming an intermediate refractive index film 7, and a step of forming an outermost film 8, in addition to the above.

[0076] In this specification, when a film is formed on a certain member, this includes both the case where the film is formed directly on the member and the case where the film is formed indirectly via another film. Hereinafter, forming a film on the first main surface 2a of the substrate 2 may be simply referred to as forming a film on the substrate 2.

[0077] In the process of forming a Ge film on the substrate 2, the chamber 21 of the vacuum evaporation film-forming apparatus 20 is depressurized by a vacuum pump. In this embodiment, oxygen is introduced into the chamber 21 from the gas inlet 27 at the same time as the pressure inside the chamber 21 of the vacuum evaporation film-forming apparatus 20 is reduced. Therefore, oxygen is present in the chamber 21 when the Ge film is formed. As a result, the concentration of oxygen contained in the formed Ge film is increased.

[0078] In the process of forming a Ge film on the substrate 2, oxygen is introduced into the chamber 21 of the vacuum evaporation film-forming apparatus 20 to reduce the pressure in the chamber 21 to 0.8×10 -3 Pa or more, and 1×10 -3 On the other hand, it is more preferable to set the pressure in the chamber 21 to 7×10 Pa or more. -3 Pa or less, and 3×10 -3 It is more preferable to set the pressure to not more than Pa. In this case, the Ge film can be suitably deposited on the substrate 2, and the concentration of oxygen contained in the Ge film can be increased to the extent that the transmittance does not decrease too much.

[0079] Next, the deposition material 22 made of Ge is heated and evaporated. This generates an evaporation flow V, as shown by the dashed line in FIG. 3. At this time, the shutter 25 is positioned so as not to block the Ge evaporation flow V from flowing toward the substrate 2. This allows a Ge film to be formed on the substrate 2.

[0080] In this embodiment, the deposition material 22 made of Ge is evaporated using a direct heating method. The direct heating method is a method in which the deposition material 22 is evaporated by directly heating the deposition material 22.

[0081] More specifically, as shown in FIG. 4, for example, an electron beam B is irradiated onto a deposition material 22 made of Ge, thereby directly heating the deposition material 22. The electron beam B is irradiated by an electron beam irradiation device 24 shown in FIG. 3. When the direct heating method is used, the energy of the evaporation flow V directed toward the substrate 2 can be increased. This can improve the adhesion of the Ge film.

[0082] After the process of forming the Ge film on the substrate 2, the introduction of oxygen into the chamber 21 of the vacuum evaporation film-forming apparatus 20 is stopped. Even after the introduction of oxygen is stopped, the pressure inside the chamber 21 is still reduced by the vacuum pump. As a result, the pressure inside the chamber 21 becomes lower than when oxygen was being introduced.

[0083] In this embodiment, the process of forming a YF3 film on the substrate 2 is performed under the condition that the pressure in the chamber 21 of the vacuum evaporation film-forming apparatus 20 is 0.7×10 -3 This is performed after the pressure in the chamber 21 has reached or below the pressure of 10 Pa. This allows the YF3 film to be deposited properly. However, the pressure in the chamber 21 when the process of depositing the YF3 film is started is not limited to the above.

[0084] In the process of forming a YF3 film on the substrate 2, a vapor deposition material 22 made of YF3 is placed in a container 23. Next, the vapor deposition material 22 is heated and evaporated, thereby generating an evaporation flow V of YF3. At this time, the shutter 25 is positioned so as not to block the evaporation flow V of YF3 from flowing toward the substrate 2. In this way, a YF3 film is formed on the first main surface 2a of the substrate 2.

[0085] In this embodiment, the evaporation material 22 made of YF is evaporated using an indirect heating method, which involves heating a container 23 in which the evaporation material 22 is placed, thereby indirectly heating and evaporating the evaporation material 22.

[0086] More specifically, when the indirect heating method is used in the vacuum evaporation film-forming apparatus 20, the vacuum evaporation film-forming apparatus 20 includes, for example, the configuration shown in Fig. 5. In this configuration, the electron beam irradiation device 34 is disposed inside the cover 31.

[0087] The cover 31 is provided with a container placement portion 31a. The container placement portion 31a is, for example, a through-hole. When the container 23 is placed in the container placement portion 31a, the container placement portion 31a is covered by the container 23. At this time, the bottom of the container 23 is located inside the cover 31. In this state, the electron beam B is irradiated onto the container 23 by the electron beam irradiation device 34. This heats the container 23, and the temperature of the container 23 increases. Accordingly, the deposition material 22 placed in the container 23 is heated. However, in the present invention, a direct heating method may be used when forming a film of YF3.

[0088] The adhesive film 4, the intermediate refractive index film 7, and the outermost film 8 shown in FIG. 1 may also be formed by vacuum deposition using an appropriate deposition material 22.

[0089] A feature of the manufacturing method of the third embodiment is that oxygen is introduced into the vacuum evaporation deposition apparatus 20 in the process of forming a Ge film on the substrate 2. This can improve the reliability of the functional film-coated substrate 1. This effect will be specifically shown below by comparing the process of forming a Ge film in the third embodiment with the process of forming a Ge film in the comparative example.

[0090] In the comparative example, a process of forming a Ge film was performed without introducing oxygen into the chamber 21 of the vacuum evaporation film-forming apparatus 20 shown in Fig. 3. In the comparative example, the pressure in the chamber 21 was set to 0.7 × 10 -3 It was named Pa.

[0091] In contrast, in the third comparative embodiment, oxygen is introduced into the chamber 21 of the vacuum evaporation film-forming apparatus 20, thereby reducing the pressure in the chamber 21 to 1×10 -3 Pa or higher, 3×10 -3 The Ge film was formed in a state of 0.1 Pa or less.

[0092] Film-coated substrates were obtained by the process of forming a Ge film in the third embodiment for comparison and the process of forming a Ge film in the comparative example. The film stress of the Ge film was compared by comparing the magnitude of warpage of these film-coated substrates. Hereinafter, the magnitude of warpage will be referred to as the warpage amount. The greater the warpage amount of the film-coated substrate, the greater the film stress of the Ge film. A three-dimensional non-contact measuring device was used to measure the warpage amount of each film-coated substrate.

[0093] FIG. 6 is a schematic perspective view for explaining a method for measuring the amount of warpage of a film-coated substrate.

[0094] The film-coated substrate 100 has a substrate 102 and a film 103. The film 103 is provided on the main surface of the substrate 102. The film 103 corresponds to, for example, a Ge film. As shown by the arrow S in FIG. 6, the film-coated substrate 100 is scanned from one edge to the other edge using a three-dimensional non-contact measuring device. This measures the displacement in the thickness direction at each position on the film-coated substrate 100. When the displacement in the thickness direction at both end edges of the film-coated substrate 100 is set to 0, the displacement in the thickness direction at each position is the amount of warpage.

[0095] 7 is a diagram showing the amount of warpage in each film-coated substrate obtained by the process of forming a Ge film in the third embodiment and the comparative example. In FIG. 7, the horizontal axis indicates positions 0 mm and 25 mm, respectively, at both edge portions of the film-coated substrate.

[0096] As shown in FIG. 7, in the third embodiment and the comparative example, the warpage of the film-coated substrate is a negative value. This indicates that the film stress of the Ge film is tensile stress. However, the absolute value of the warpage in the third embodiment is significantly smaller than that in the comparative example. Therefore, in the third embodiment, the film stress of the Ge film can be reduced.

[0097] As described above, the Ge film corresponds to the high-refractive index film 5 shown in FIG. 1. Furthermore, since the film stress of the high-refractive index film 5 can be reduced, peeling of the functional film 3 can be suppressed. More specifically, both peeling of the functional film 3 from the substrate 2 and peeling between layers of the functional film 3 can be suppressed. As a result, even when the functional film-coated substrate 1 is used for a long period of time, its weather resistance is less likely to decrease and its translucency is less likely to deteriorate. As a result, even when the functional film-coated substrate 1 is used in a high-humidity environment, it can maintain high infrared transmittance for a long period of time. Therefore, the reliability of the functional film-coated substrate 1 can be increased.

[0098] This is because oxygen is introduced into the chamber 21 of the vacuum evaporation film-forming apparatus 20 in the step of forming a Ge film on the substrate 2 in the manufacturing method of the third embodiment. This increases the concentration of oxygen contained in the Ge film, thereby reducing the film stress of the Ge film.

[0099] In the process of forming a Ge film on the substrate 2, oxygen is introduced into the chamber 21 of the vacuum evaporation film-forming apparatus 20 to reduce the pressure in the chamber 21 to 0.7×10 -3 It is preferable to set the pressure in the chamber 21 to be higher than 0.8×10 Pa. This makes it easier to reduce the film stress of the Ge film. -3 It is more preferable that the pressure is 1×10 Pa or more. -3 It is more preferable to set the pressure to at least Pa. This makes it possible to more reliably and effectively reduce the film stress of the Ge film.

[0100] On the other hand, in the process of forming a Ge film on the substrate 2, when oxygen is introduced into the chamber 21 of the vacuum evaporation film-forming apparatus 20, the pressure in the chamber 21 is increased to 7×10 -3 Pa or less, and 3×10 -3 It is more preferable to set the pressure to 0.1 Pa or less. This more reliably prevents the infrared transmittance of the Ge film from decreasing, even compared to when oxygen is not introduced into the chamber 21. Therefore, it is possible to more reliably increase the infrared transmittance of the Ge film. The effect of this will be described below.

[0101] The infrared transmittance was compared between a functional film-attached substrate fabricated using the manufacturing method of the third embodiment and a functional film-attached substrate fabricated using the manufacturing method of the first reference example. In the third embodiment for comparison, in the step of forming a Ge film on the substrate 2, oxygen was introduced into the chamber 21 of the vacuum evaporation film-forming apparatus 20, thereby reducing the pressure in the chamber 21 to 1×10 -3 Pa or higher, 3×10 -3 Pa or less.

[0102] On the other hand, in the first reference example, in the process of forming a Ge film on the substrate 2, oxygen was not introduced into the chamber 21 of the vacuum evaporation film-forming apparatus 20, and the pressure in the chamber 21 was set to 0.7×10 -3 Pa. The manufacturing method of the first reference example is the same as the manufacturing method of the third embodiment except for the step of forming a Ge film on the substrate 2.

[0103] In the comparative third embodiment and the first reference example, the layer structure of the functional film was as shown in Table 1. The first layer in Table 1 is an adhesive film, and the ninth layer is the outermost film. Among the second to eighth layers, the layer made of Ge is a high-refractive index film, the layer made of YF3 is a low-refractive index film, and the layer made of ZnS is an intermediate-refractive index film. In the comparative third embodiment and the first reference example, the functional film having the layer structure shown in Table 1 was provided on both the first and second main surfaces of the substrate. A chalcogenide glass substrate was used as the substrate. The infrared transmittance of each functional film-coated substrate was measured using an FT-IR (Fourier transform infrared spectrophotometer).

[0104] [Table 1]

[0105] FIG. 8 is a diagram showing the infrared transmittance of the functional film-coated substrates obtained by the manufacturing methods of the third embodiment and the first reference example.

[0106] As shown in Figure 8, the infrared transmittance of the functional film-coated substrate in the third embodiment is not significantly deteriorated compared to the first reference example. Furthermore, in the third embodiment, the infrared transmittance is 80% or more at wavelengths of 8 μm or more and 14 μm or less. Therefore, the functional film-coated substrate obtained by the manufacturing method of the third embodiment is particularly suitable for use in applications that transmit light with a central wavelength of 8 μm or more and 14 μm or less.

[0107] Here, the pressure in the chamber 21 of the vacuum evaporation film-forming apparatus 20 shown in FIG.-3 Pa or higher, 3×10 -3 The figure shows the relationship between the position in the thickness direction of the Ge film and the concentration of oxygen contained in the Ge film when the Ge film is formed at a pressure of 0.7 × 10 Pa or less. -3 1 shows the relationship between the position in the thickness direction of the Ge film and the concentration of oxygen contained in the Ge film when the Ge film is formed using Pa.

[0108] The above pressure is 1×10 -3 Pa or higher, 3×10 -3 When the Ge film was formed at a pressure of 0.7×10 Pa or less, five deposition materials 22 were used. -3 When the Ge film was formed as Pa, two deposition materials 22 were used.

[0109] Figure 9 shows the pressure in the chamber of the vacuum evaporation deposition device at 1×10 -3 Pa or higher, 3×10 -3 Pa or less, and 0.7 × 10 -3 9 is a diagram showing the relationship between the position in the thickness direction of the formed Ge film and the concentration of oxygen contained therein when the pressure in the chamber 21 of the vacuum evaporation film-forming apparatus 20 is 1×10 Pa. G1 to G5, G11, and G12 in FIG. 9 indicate the deposition materials 22 used when depositing each portion of the Ge film. Specifically, G1 to G5 are the deposition materials 22 used when the pressure in the chamber 21 of the vacuum evaporation film-forming apparatus 20 is 1×10 -3 Pa or higher, 3×10 -3 On the other hand, G11 and G12 show the deposition material 22 used when forming the Ge film when the pressure was 0.7×10 Pa or less. -3 The deposition material 22 used when forming the Ge film is shown in Pa.

[0110] 9, the concentration of oxygen contained in the Ge film is relatively stable in the portion of the Ge film having a thickness of 0.1 μm or more and 1.1 μm or less in the thickness direction. -3 When the pressure was set to Pa, the average concentration of oxygen contained in the above-mentioned part of the Ge film formed was 3.8 × 10 19As described above, when forming the Ge film, the pressure in the chamber 21 of the vacuum evaporation film-forming apparatus 20 is set to 0.7×10 -3 When the oxygen concentration in the Ge film is set to be higher than 3.8×10 Pa, the film stress of the Ge film can be easily reduced. 19 It is preferable to set the concentration higher than atoms / cc, which has the effect of making it easier to reduce the film stress of the Ge film.

[0111] On the other hand, the pressure in the chamber 21 of the vacuum evaporation film-forming apparatus 20 is set to 1×10 -3 Pa or higher, 3×10 -3 When the pressure is set to 0.1 μm or less, the oxygen concentration in the part of the Ge film formed from 0.1 μm to 1.1 μm in the thickness direction is within the following range: 20 atoms / cc or more, 4.6×10 20 The oxygen concentration in the Ge film is 0.1 μm or more and 1.1 μm or less in the thickness direction, and the oxygen concentration in the Ge film is 1.8×10 or less. The ... 20 The oxygen concentration in the range in the thickness direction, excluding the portion where the oxygen concentration increased when the deposition material 22 was switched, was about 1.8×10 20 The range is within ±40% of atoms / cc.

[0112] As described above, when forming the Ge film, the pressure in the chamber 21 of the vacuum evaporation film-forming apparatus 20 is set to 1×10 -3 Pa or higher, 3×10 -3 When the oxygen concentration in the Ge film is set to 1.1×10 Pa or less, the film stress of the Ge film can be more reliably reduced. 20 atoms / cc or more, 4.6×10 20 It is more preferable to keep it below 1.8×10 atoms / cc. 20It is more preferable to set the range to within ±40% of atoms / cc. This makes it possible to more reliably reduce the film stress of the Ge film. Therefore, it is possible to more reliably increase the reliability of the functional film-coated substrate 1 including the Ge film as the high refractive index film 5.

[0113] As in the manufacturing method of the third embodiment, in the step of forming the YF3 film, the deposition material 22 made of YF3 is preferably heated by indirect heating.

[0114] Generally, when forming a film of a fluoride such as YF3 by vacuum deposition, the deposition material made of fluoride is heated by a direct heating method. This can improve the adhesion of the fluoride film to the substrate or other films. However, this tends to increase the film stress of the fluoride film such as YF3.

[0115] In contrast, as shown in FIG. 5, by heating the evaporation material 22 made of YF3 by an indirect heating method, it is possible to prevent the energy of the evaporation flow V of YF3 heading toward the substrate 2 shown in FIG. 3 from becoming too high. This prevents the energy of YF3 particles colliding with the substrate 2 from becoming too high. This reduces the film stress of the YF3 film. This effect will be demonstrated below by comparing the process of forming a YF3 film in the third embodiment with the process of forming a YF3 film in the second reference example.

[0116] Film-coated substrates were obtained by the process of forming a YF3 film in the third comparative embodiment and the process of forming a YF3 film in the second reference example. The film stress of the YF3 film was compared by comparing the amount of warpage of these film-coated substrates. The greater the amount of warpage of the film-coated substrate, the greater the film stress of the YF3 film. The amount of warpage of each film-coated substrate was measured using a three-dimensional non-contact measuring device in the same manner as described with reference to FIG. 6.

[0117] 10 is a diagram showing the amount of warpage in each film-coated substrate obtained by the process of forming a YF3 film in the third embodiment and the second reference example. In FIG. 10, the positions 0 mm and 25 mm indicated on the horizontal axis indicate both edge portions of the film-coated substrate.

[0118] As shown in FIG. 10, in the second reference example, the amount of warpage of the film-coated substrate is a positive value. This indicates that the film stress of the YF3 film in the second reference example is compressive stress. In contrast, the absolute value of the amount of warpage of the YF3 film in the third embodiment is significantly smaller than the absolute value of the amount of warpage in the comparative example. Therefore, in the third embodiment, the film stress of the YF3 film can be reduced.

[0119] Furthermore, a weather resistance test was conducted on the film-coated substrates obtained by the process of forming the YF3 film in the third embodiment and the process of forming the YF3 film in the second reference example. Specifically, each film-coated substrate was placed in an environment of 85°C and 85% humidity for 168 hours. After that, each film-coated substrate was photographed.

[0120] Fig. 11 is a photograph of the film-coated substrate obtained by the process of forming a YF3 film in the second reference example after the film-coated substrate was placed in a high-temperature and high-humidity environment. Fig. 12 is a photograph of the film-coated substrate obtained by the process of forming a YF3 film in the third embodiment after the film-coated substrate was placed in a high-temperature and high-humidity environment.

[0121] As shown in Figure 11, partial peeling of the YF3 film occurs in the second reference example. In contrast, as shown in Figure 12, peeling of the YF3 film hardly occurs in the third embodiment. As described above, according to the process of forming the YF3 film in the third embodiment, peeling of the YF3 film can be suppressed even after the film-coated substrate is placed in a high-temperature, high-humidity environment. Therefore, the weather resistance of the film-coated substrate on which the YF3 film is formed can be improved.

[0122] As described above, the YF3 film corresponds to the low-refractive-index film 6 shown in FIG. 1. Furthermore, since the film stress of the low-refractive-index film 6 can be reduced, peeling of the functional film 3 can be suppressed. More specifically, both peeling of the functional film 3 from the substrate 2 and peeling between layers of the functional film 3 can be suppressed. As a result, even when the functional film-coated substrate 1 is used for a long period of time, its weather resistance is less likely to decrease and its light transmittance is less likely to deteriorate. As a result, even when the functional film-coated substrate 1 is used in a high-humidity environment, it can maintain high infrared transmittance for a long period of time. Therefore, the reliability of the functional film-coated substrate 1 can be increased.

[0123] The film stress of both the Ge film and the YF3 film formed by the manufacturing method of the third embodiment is a small tensile stress. As such, it is preferable that the film stress of the Ge film and the YF3 film be in the same direction. This makes it even less likely that peeling will occur between layers of the functional film 3. This can further increase the reliability of the functional film-coated substrate 1.

[0124] Here, a reliability test was carried out on the functional film-attached substrate obtained by the manufacturing method of the third embodiment. The layer structure of the functional film in the functional film-attached substrate was as shown in Table 1. A chalcogenide glass substrate was used as the substrate.

[0125] In the reliability test, specifically, the infrared transmittance of the functional film-coated substrate was measured before placing it in a high-temperature, high-humidity environment. Next, the functional film-coated substrate was placed in an environment of 125°C and 85% humidity for 168 hours. After that, the infrared transmittance of the functional film-coated substrate was measured again. The infrared transmittance of the functional film-coated substrate was measured using an FT-IR (Fourier transform infrared spectrophotometer).

[0126] Figure 13 is a diagram showing the infrared transmittance of a functional film-coated substrate obtained by the manufacturing method of the third embodiment before and after being placed in a high-temperature, high-humidity environment.

[0127] 13, it can be seen that the infrared transmittance of the functional film-coated substrate is hardly deteriorated even after being placed in a high-temperature, high-humidity environment compared to before being placed in the high-temperature, high-humidity environment. In this way, the manufacturing method of the third embodiment can effectively increase the reliability of the functional film-coated substrate 1. [Explanation of symbols]

[0128] 1...Functional film-coated substrate 2...Substrate 2a, 2b...first and second principal surfaces 3...Functional membrane 4...Adhesive film 5...High refractive index film 6...Low refractive index film 7...Intermediate refractive index film 8…Outermost membrane 11...Functional film-coated substrate 13...Functional membrane 20...Vacuum evaporation film forming equipment 21...Chamber 22...Vapor deposition material 23…Container 24...Electron beam irradiation device 25...Shutter 26...Substrate dome 27...Gas inlet 28...Heater 29...Film thickness gauge 31...Cover 31a...Container arrangement part 34...Electron beam irradiation device 100...film-coated substrate 102... Circuit board 103...Membrane V: Evaporation flow B...electron beam

Claims

1. A method for manufacturing a functional film-coated substrate, in which a functional film having a Ge film containing Ge as a main component is provided on a substrate by using a vacuum evaporation film-forming apparatus, comprising: providing the substrate; placing the substrate in the vacuum evaporation deposition apparatus; forming the Ge film on the substrate; Equipped with The method for manufacturing a functional film-formed substrate, wherein oxygen is introduced into the vacuum evaporation deposition apparatus in the step of forming the Ge film on the substrate.

2. In the step of forming the Ge film on the substrate, the pressure in the vacuum evaporation film-forming apparatus is 0.8×10 －３ Pa or more, 7×10 －３ The method for producing a functional film-coated substrate according to claim 1 , wherein the pressure is 0.05 Pa or less.

3. 3. The method for producing a functional film-formed substrate according to claim 1, wherein the introduction of oxygen into the vacuum evaporation film-forming apparatus is stopped after the step of forming the Ge film on the substrate.

4. By using the vacuum evaporation film-forming apparatus, the Ge film and the YF ３ YF containing as the main component ３ a functional film provided on the substrate, the functional film comprising: The YF ３ The method further comprises the step of depositing a film, The YF ３ The film forming step is performed by setting the pressure in the vacuum evaporation film forming apparatus to 0.7×10 －３ The method for producing a functional film-coated substrate according to claim 3 , wherein the step is carried out after the pressure has reached a value of not more than 100 Pa.

5. By using the vacuum evaporation film-forming apparatus, the Ge film and the YF ３ YF containing as the main component ３ a functional film provided on the substrate, the functional film comprising: The YF ３ The method further comprises the step of depositing a film, the vacuum evaporation film-forming apparatus has a container in which an evaporation material is placed, The YF ３ In the film forming step, YF ３ 5. The method for producing a functional film-coated substrate according to claim 4, wherein an indirect heating method is used, in which the evaporation material is evaporated by heating the container in which the evaporation material is placed.

6. 3. The method for manufacturing a functional film-coated substrate according to claim 1, wherein in the step of forming the Ge film on the substrate, a direct heating method is used in which the deposition material consisting of Ge is evaporated by directly heating the deposition material.

7. The method for producing a functional film-coated substrate according to claim 1 or 2, wherein the substrate is a chalcogenide glass substrate.

8. The method for producing a functional film-coated substrate according to claim 1 or 2, wherein the functional film is an anti-reflection film.

9. a chalcogenide glass substrate; an anti-reflection film provided on the chalcogenide glass substrate; Equipped with The anti-reflection film is a high-refractive index film having a relatively high refractive index, which is a Ge film containing Ge as a main component, and a low-refractive index film having a relatively low refractive index, which is YF ３ YF containing as the main component ３ a membrane; The concentration of oxygen contained in the Ge film is ３ A chalcogenide glass substrate with an anti-reflective coating, the concentration of oxygen in the film being higher than that of the film.

10. 10. The chalcogenide glass substrate with an anti-reflection film according to claim 9, wherein the center wavelength of light to be transmitted is 8 [mu]m or more and 14 [mu]m or less.

Images