Reflectivity adjustment film, laminate, and method for producing reflectivity adjustment film

Abstract

Provided is a reflectivity adjusting film having high hardness. A reflectance adjusting film (10) for adjusting the reflectance of light, in which a plurality of films are laminated, the plurality of films including a low refractive index film (11) and a high refractive index film (12) having a refractive index greater than that of the low refractive index film (11), the low refractive index film (11) being formed from a mixture containing silica (SiO2) and yttrium oxide (Y2O3), the yttrium oxide (Y2O3) having a refractive index greater than that of the low refractive index film (11), and the refractive index of the high refractive index film (12) being greater than that of the low refractive index film (11). Some of the yttrium (Y) atoms are substituted by atoms of a group 4A element, and the refractive index of at least one of the films adjacent to the high refractive index film (12) is lower than the refractive index of the high refractive index film (12).

Description

Technical Field

[0001] The present disclosure relates to a reflectance adjusting film, a laminate, and a method for producing the reflectance adjusting film. Background Art

[0002] Sometimes, a reflectivity-adjusting film that adjusts the reflectivity of light is laminated on a surface of a glass substrate or the like. For example, Patent Document 1 describes an antireflection film that acts as a reflectivity-adjusting film and prevents light reflection. The antireflection film described in Patent Document 1 can be formed, for example, by alternately laminating a low-refractive-index film and a high-refractive-index film on a glass substrate.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1 International Publication No. 2019-151321 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] Since the reflectivity adjustment film structured as in Patent Document 1 has low hardness (softness), it may be damaged during use. Therefore, in order to increase the hardness of the reflectivity adjustment film and improve its scratch resistance, a hard coating layer may be provided on the substrate as a separate layer from the reflectivity adjustment film.

[0008] However, when a hard coat layer is provided as a separate film from the reflectance adjusting film, the number of steps increases accordingly. In addition, when the reflectance adjusting film is formed on the hard coat layer, there is a risk of foreign matter being mixed into the reflectance adjusting film.

[0009] Therefore, an object of the present disclosure is to provide a reflectance adjusting film having high hardness, a laminated body having the reflectance adjusting film formed thereon, and a method for producing the reflectance adjusting film.

[0010] Solutions to Problems

[0011] To achieve this object, the reflectance adjusting film of the present disclosure is a reflectance adjusting film for adjusting the reflectance of light.

[0012] It is a stack of multiple films.

[0013] The plurality of films include a low refractive index film and a high refractive index film having a refractive index greater than that of the low refractive index film,

[0014] The low refractive index film is formed of a mixture containing silicon dioxide (SiO2) and yttrium oxide (Y2O3), wherein a portion of yttrium (Y) atoms in the yttrium oxide (Y2O3) are replaced by atoms of a 4A group element.

[0015] At least one of the films adjacent to the high-refractive-index film has a refractive index smaller than that of the high-refractive-index film.

[0016] The laminate of the present disclosure is a laminate in which the reflectance adjustment film of the present disclosure is formed on at least one surface of a substrate.

[0017] The manufacturing method of the reflectivity adjustment film of the present disclosure includes a low refractive index film forming process for forming the low refractive index film and a high refractive index film forming process for forming the high refractive index film. In the low refractive index film forming process, the low refractive index film is formed by a sputtering method, and in the high refractive index film forming process, the high refractive index film is formed by a sputtering method.

[0018] Effects of the Invention

[0019] According to the present disclosure, it is possible to provide a reflectance adjusting film having high hardness, a laminated body having the reflectance adjusting film formed thereon, and a method for producing the reflectance adjusting film. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a cross-sectional view showing an example of the reflectance adjustment film of the present disclosure and the laminate of the present disclosure.

[0021] Figure 2 This is a cross-sectional view showing an example of a laminate having a hard coat layer and a reflectance adjustment film according to the present disclosure. DETAILED DESCRIPTION

[0022] In the present disclosure, "on" or "on the surface" may refer to a state where the material is on the surface or in direct contact with the surface, or may refer to a state where the material is interposed with other layers, etc.

[0023] In the present disclosure, unless otherwise specified, “suppression” of a certain phenomenon is not limited to suppressing the occurrence of the phenomenon to a smaller extent, but also includes eliminating the occurrence of the phenomenon.

[0024] In the present disclosure, unless otherwise specified, a "reflectance adjustment film" refers to a film structure that can adjust the reflectance of incident light by changing the film thickness, refractive index, etc.

[0025] In the present disclosure, unless otherwise specified, the term "film thickness" may refer to either "physical film thickness" or "optical film thickness".

[0026] The following describes specific embodiments of the present disclosure using accompanying drawings and other figures as needed. For ease of explanation, each figure is schematically drawn and may be omitted or exaggerated as appropriate. In addition, when mechanisms and principles are mentioned in the following embodiments and examples, the mechanisms and principles described are merely assumptions and are not intended to be limiting.

[0027] [1. Reflectance Adjusting Film and Laminate]

[0028] First, the reflectance adjustment film of the present disclosure and the laminated body of the present disclosure are described as examples.

[0029] [1-1. Structure of Reflectance Adjusting Film, Laminate, etc.]

[0030] Figure 1 The cross-sectional view schematically shows the structure of an example of a reflectivity adjustment film of the present disclosure and a laminate of the present disclosure using the same. As shown in the figure, the laminate 100 of the present disclosure has the reflectivity adjustment film 10 of the present disclosure formed on one surface of a substrate 20. The reflectivity adjustment film 10 is a film formed by stacking a plurality of films (a low refractive index film 11 and a high refractive index film 12 described later) on which light is incident. The reflectivity adjustment film 10 is formed by alternately stacking low refractive index films 11 and high refractive index films 12. In the figure, the film adjacent to the substrate 20 and the film farthest from the substrate 20 are the low refractive index films 11, respectively.

[0031] The lamination order of the low refractive index film 11 and the high refractive index film 12 is not particularly limited. However, when the reflectance adjustment film 10 is used as an antireflection film, the film farthest from the substrate 20 is the low refractive index film 11 .

[0032] exist Figure 1 In the reflectivity adjustment film of the present disclosure, the number of low refractive index films 11 is 3 layers, and the number of high refractive index films 12 is 2 layers. However, in the reflectivity adjustment film of the present disclosure, the number of low refractive index films and high refractive index films is not limited, and each has at least 1 layer. In the reflectivity adjustment film of the present disclosure, the total lower limit of the number of low refractive index films and high refractive index films is preferably more than 3 layers, more preferably more than 5 layers, and the upper limit is not particularly limited, for example, it can also be less than 30 layers, less than 20 layers, less than 15 layers or less than 10 layers. The smaller the total number of low refractive index films and high refractive index films (that is, the fewer the total number of layers of low refractive index films and high refractive index films), the more time required for producing the reflectivity adjustment film of the present disclosure can be shortened, or the cost required for production can be reduced, so it is preferred. In addition, the larger the total number of low refractive index films and high refractive index films (that is, the more the total number of layers of low refractive index films and high refractive index films), the easier it is to obtain the target reflectivity of the reflectivity adjustment film of the present disclosure, so it is preferred.

[0033] The substrate 20 is not particularly limited, and for example, it may be a plate-shaped substrate. In addition, the material of the substrate 20 may also be glass, resin, etc. As glass, for example, glass plates, glass lenses, etc. may be mentioned. As resin, for example, resin plates, resin lenses, etc. may be mentioned. The material of the resin is not particularly limited, and for example, polyolefins, polyesters, PC (polycarbonate), acrylic resins, etc. may be mentioned. As the polyolefins, for example, PP (polypropylene), PE (polyethylene), COP (cycloolefin polymer), etc. may be mentioned. As the polyesters, for example, PET (polyethylene terephthalate), etc. may be mentioned. As the acrylic resins, for example, PMMA (polymethyl methacrylate), etc. may be mentioned. In addition, in Figure 1 In the embodiment, the substrate 20 is a single layer, but the substrate 20 is not limited thereto and may be a laminate of multiple layers, in which case the layers may be the same or different. The laminate 100 may be, for example, a lens or window glass having the reflectivity adjustment film 10 .

[0034] Figure 1 The reflectivity adjustment film 10 includes only the low refractive index film 11 and the high refractive index film 12. However, the reflectivity adjustment film of the present disclosure is not limited thereto and may include other layers in addition to the low refractive index film and the high refractive index film. In addition, the number of low refractive index films 11 is 3, and the number of high refractive index films 12 is 2. Figure 1 Although the reflectivity adjustment film 10 is laminated by directly contacting the low refractive index film 11 and the high refractive index film 12, the structure of the present disclosure is not limited to this structure, and for example, other layers other than the low refractive index film and the high refractive index film may be laminated. Figure 1 In the embodiment, the reflectance adjusting film 10 is laminated on the substrate 20 in direct contact with the substrate 20. However, the present disclosure is not limited thereto. For example, the reflectance adjusting film 10 may be laminated on the substrate 20 via layers other than the low refractive index film 11 and the high refractive index film 12. However, from the perspective of suppressing the incorporation of foreign matter from the other layers into the reflectance adjusting film, the reflectance adjusting film of the present disclosure and the laminate of the present disclosure preferably do not include layers other than the low refractive index film and the high refractive index film.

[0035] in addition, Figure 2 An example of a laminate having a hard coating layer and a reflectivity adjustment film according to the present disclosure is shown. As shown in the figure, the laminate 100a has a hard coating layer 30 formed on one surface of a substrate 20, and a reflectivity adjustment film 10a formed on the surface of the hard coating layer 30 opposite to the substrate 20. The reflectivity adjustment film 10a is formed by alternately laminating low refractive index films 11a and high refractive index films 12a. Figure 2 In the embodiment, the film adjacent to the hard coat layer 30 (closest to the substrate 20 ) and the film farthest from the substrate 20 are the low refractive index films 11 a , respectively.

[0036] like Figure 2 As shown, if a hard coating layer is used as a layer different from the reflectivity adjustment film, for example, the hardness of the reflectivity adjustment film can be increased, thereby improving the scratch resistance. However, as mentioned above, the number of steps required to form the hard coating layer increases. In addition, when forming the reflectivity adjustment film on the hard coating layer, there is a possibility that foreign matter may be mixed into the reflectivity adjustment film. In contrast, Figure 1 The reflectance adjustment film 10 has high hardness even without a hard coat layer, and thus can solve such a problem.

[0037] In the reflectivity adjustment film of the present disclosure, as described above, the low refractive index film is formed by a mixture comprising silicon dioxide (SiO2) and yttrium oxide (Y2O3), wherein, for yttrium oxide (Y2O3), a portion of the yttrium (Y) atoms are replaced by atoms of a 4A group element. For yttrium oxide (Y2O3), a portion of the oxygen (O) atoms can also be replaced by nitrogen (N) atoms. By replacing part of the oxygen (O) atoms of yttrium oxide (Y2O3) with nitrogen (N) atoms, it is expected to achieve low adhesion to alkaline substances and impart antifouling properties associated with certain substances. The principle of imparting adhesion and antifouling properties can be considered to be, for example, that by replacing part of the oxygen (O) atoms with nitrogen (N) atoms, the hydroxyl groups that are active groups on the surface of the reflectivity adjustment film are inactivated.

[0038] In addition, yttrium oxide (Y2O3) has a higher hardness than silicon dioxide (SiO2). Therefore, it is believed that the hardness of a film formed from a mixture containing yttrium oxide (Y2O3) and silicon dioxide (SiO2) is higher than the hardness of a low-refractive-index film composed only of silicon dioxide (SiO2). In addition, by replacing a portion of the yttrium (Y) atoms in yttrium oxide (Y2O3) with atoms of a 4A group element, for example, the bonding of the crystals constituting the low-refractive-index film becomes stronger. Based on this, it is believed that when a portion of the yttrium (Y) atoms in the low-refractive-index film are replaced by atoms of a 4A group element, the hardness is higher than when they are not replaced.

[0039] The hardness of the reflectivity adjustment film of the present disclosure is not particularly limited. However, when the substrate is glass, the hardness of the reflectivity adjustment film is preferably 6.0 GPa or higher, more preferably 6.1 GPa or higher. The upper limit is, for example, 11 GPa or lower.

[0040] In the present disclosure, hardness is a value measured by the method described in the Examples below. However, in the present disclosure, hardness may be measured by methods other than the measurement method described below.

[0041] The reflectivity adjustment film of the present disclosure may be an anti-reflection film, but is not limited thereto. For example, the light transmittance of the reflectivity adjustment film of the present disclosure may be approximately 0%. Such a reflectivity adjustment film may also be, for example, a mirror having a light reflectivity of approximately 100%. In the reflectivity adjustment film of the present disclosure, the reflectivity, transmittance, etc. of light can be adjusted, for example, by appropriately setting the number, film thickness, refractive index, and stacking order of the low-refractive index film and the high-refractive index film. In addition, in the reflectivity adjustment film of the present disclosure, the reflectivity, transmittance, etc. of light can also be adjusted to be different, for example, depending on the wavelength of the light.

[0042] The reflectivity adjustment film of the present disclosure adjusts the reflectivity, for example, by the following method. As described above, the reflectivity adjustment film of the present disclosure is composed of a plurality of films stacked together. The refractive indices of the plurality of films adjacent to each other have different refractive indices between the adjacent films. Here, when light is incident from one film to another, when the refractive indices of the two adjacent films are different, a portion of the incident light is reflected at the boundary between the two adjacent films. The greater the difference in the refractive indices of the two adjacent layers, the greater the intensity of the reflected light. In addition, the film thickness of the stacked plurality of films has an effect on the phase of the reflected light generated at the boundary between the two adjacent films. In the reflectivity adjustment film of the present disclosure, light is reflected at the boundaries of the respective stacked plurality of films. Therefore, by adjusting the refractive indices and film thicknesses of the stacked plurality of films, the reflectivity of the reflectivity adjustment film of the present disclosure can be adjusted.

[0043] When the reflectivity-adjusting film of the present disclosure is an antireflection film, the upper limit of the reflectivity is not particularly limited, but the average reflectivity in visible light (380 nm to 780 nm) is preferably 2.5% or less, more preferably 2.0% or less, 1.5% or less, or 1.0% or less. The lower limit of the reflectivity is not particularly limited, and for example, it is 0 or a value exceeding 0.

[0044] In addition, in the present disclosure, the reflectivity of light can also be measured using a device that can measure the reflectivity of light. As a device that can measure the reflectivity of light, for example, a reflection spectrophotometer (trade name: FE-3000) manufactured by Otsuka Electronics Co., Ltd. can be cited. The reflectivity of light can be a numerical value measured based on the wavelength of the incident light, the film thickness of the low-refractive index film and the high-refractive index film, the optical constants of these films, and the optical constants of the substrate. However, in the present disclosure, the reflectivity of light can also be measured by a method other than the above-mentioned measurement method. In addition, in the present disclosure, the reflectivity of light can be an actual measured value using a device, or a simulated value calculated by optical simulation software, etc.

[0045] [1-2. Low refractive index film]

[0046] Hereinafter, the low refractive index film in the reflectance adjustment film of the present disclosure will be described with examples.

[0047] The refractive index of the low-refractive-index film is not particularly limited, and for example, the refractive index for light having a wavelength of 500 nm is in the range of 1.47 to 1.58.

[0048] In addition, in the present disclosure, the refractive index may be, for example, a value measured using an apparatus capable of measuring the refractive index. An example of an apparatus capable of measuring the refractive index is a reflection spectrophotometer (trade name: FE-3000) manufactured by Otsuka Electronics Co., Ltd. However, in the present disclosure, the refractive index may also be measured by methods other than the following measurement method.

[0049] As described above, the low refractive index film in the reflectivity adjustment film of the present disclosure is formed by a mixture containing silicon dioxide (SiO2) and yttrium oxide (Y2O3), wherein, for yttrium oxide (Y2O3), a portion of the yttrium (Y) atoms are replaced by atoms of a 4A group element. For yttrium oxide (Y2O3), a portion of the oxygen (O) atoms can also be replaced by nitrogen (N) atoms. The content of yttrium oxide in the low refractive index film is not particularly limited. For example, the lower limit is preferably 1.0 mol% or more, more preferably 1.1 mol% or more. From the viewpoint of improving anti-reflection performance, the upper limit is preferably less than 10 mol%, more preferably less than 6 mol%.

[0050] In addition, in the present disclosure, the atomic content in the film can be, for example, a value measured using an X-ray photoelectron spectrometer. An example of an X-ray photoelectron spectrometer is the X-ray photoelectron spectrometer manufactured by ULVAC-PH I Co., Ltd. (trade name: PH I 5000 VersaProbe 2). An X-ray photoelectron spectrometer irradiates a sample with X-rays and measures the energy of photoelectrons emitted from the sample surface, thereby obtaining information about the surface composition and chemical bonding state. Therefore, the atomic content in the film can be measured. In the present disclosure, the atomic content in the film can also be measured using methods other than the following measurement method.

[0051] The low refractive index film in the reflectance adjustment film of the present disclosure may or may not contain other components besides silicon dioxide (SiO2) and yttrium oxide (Y2O3). Examples of other components include magnesium fluoride (MgF2).

[0052] In the reflectivity adjustment film of the present disclosure, a portion of the yttrium (Y) atoms in the yttrium oxide (Y2O3) contained in the low-refractive-index film are replaced by atoms of a Group 4A element. The atoms of the Group 4A element are not particularly limited, and for example, may be at least one selected from the group consisting of titanium (Ti), zirconium (Zr), and hafnium (Hf), preferably at least one of zirconium (Zr) and hafnium (Hf), with zirconium (Zr) being particularly preferred. These atoms or their forming materials may be used singly or in combination.

[0053] The reflectivity-adjusting film of the present disclosure can achieve, for example, higher hardness (such as scratch resistance) by replacing a portion of the yttrium (Y) atoms in the yttrium oxide (Y2O3) contained in the low-refractive-index film with atoms of a Group 4A element. This is because, for example, a material in which a portion of the yttrium (Y) atoms are replaced with atoms of a Group 4A element (e.g., zirconium (Zr)) is believed to have a higher hardness than yttrium oxide (Y2O3).

[0054] In addition, the low-refractive-index film in the reflectivity-adjusting film of the present disclosure may also be crystalline, for example. Whether the low-refractive-index film is crystalline can be confirmed, for example, by conventional crystallinity evaluation methods such as X-ray diffraction, electron beam diffraction, and Raman spectroscopy. In addition, for example, secondary ion mass spectrometry (SIMS) can be used to confirm that the low-refractive-index film contains yttrium oxide containing nitrogen and a Group 4A element.

[0055] In the low refractive index film, the substitution rate of yttrium (Y) atoms in yttrium oxide (Y2O3) by atoms of 4A group elements (the content of atoms of 4A group elements) is not particularly limited as long as it exceeds 0. The upper limit value is, for example, less than 20 mol%, less than 15 mol%, less than 10 mol% or less than 5 mol%.

[0056] In the low refractive index film, for yttrium oxide (Y2O3), when a part of the oxygen (O) atoms are replaced by nitrogen (N) atoms, the substitution rate (nitrogen atom content) of the oxygen (O) atoms in yttrium oxide (Y2O3) by nitrogen (N) atoms is not particularly limited as long as it exceeds 0, and can be greater than 1 atomic %. The upper limit value is, for example, less than 10 atomic %, less than 5 atomic %, less than 3 atomic % or less than 2 atomic %.

[0057] In addition, the low refractive index film may not contain metal elements or harmful metals that are allergy-inducing components, such as Hg, Ni, Cr, Co, Cu, Sn, Au, Pt, Pd, Sb, Ag, Fe or Zn.

[0058] The physical film thickness of the low-refractive-index film is not particularly limited and can be appropriately selected according to the target optical properties.

[0059] In addition, in the present disclosure, the physical film thickness may be a value measured by a spectroscopic film thickness meter. According to the spectroscopic film thickness meter, by irradiating light to the sample and measuring the optical interference phenomenon caused by the phase shift generated by the optical path difference of the reflected light relative to the irradiated light, the film thickness can be measured based on the obtained reflection spectrum and refractive index. As an example of a spectroscopic film thickness meter, a reflection spectroscopic film thickness meter (trade name: FE-3000) manufactured by Otsuka Electronics Co., Ltd. can be cited. However, in the present disclosure, the physical film thickness may also be measured by methods other than the above-mentioned measurement methods.

[0060] [1-3. High refractive index film]

[0061] Hereinafter, the high refractive index film among the reflectance adjustment films of the present disclosure will be described with examples.

[0062] The refractive index of the high refractive index film is not particularly limited as long as it is higher than that of the low refractive index film. For example, for the refractive index of light with a wavelength of 500 nm, the lower limit is preferably 1.9 or more, and the upper limit is preferably 2.75 or less, 2.5 or less, or 2.3 or less.

[0063] In the reflectivity adjustment film of the present disclosure, the material forming the high refractive index film is not particularly limited. For example, it can be formed from at least one selected from tantalum pentoxide (Ta2O5), niobium pentoxide (Nb2O5), titanium oxide (TiO2), zirconium oxide (ZrO2) and cerium oxide (CeO2), or it can be formed from other materials. From the perspective of taking both hardness and refractive index into account, the high refractive index film is preferably formed from tantalum pentoxide. In addition, when the high refractive index film is formed from tantalum pentoxide, it may or may not contain other materials. These atoms or their forming materials may be used alone, or multiple of these atoms and their forming materials may be combined.

[0064] The physical film thickness of the high refractive index film is not particularly limited and can be appropriately selected according to the target optical properties.

[0065] [1-4. Other films]

[0066] The reflectivity adjustment film of the present disclosure may include, for example, other films. Examples of such other films include medium refractive index films. The medium refractive index film is not particularly limited as long as its refractive index is higher than that of the low refractive index film and lower than that of the high refractive index film. The material forming the medium refractive index film is not particularly limited and, for example, may be formed from aluminum oxide (Al2O3) or other materials.

[0067] [2. Method for Manufacturing Reflectance Adjusting Film and Method for Manufacturing Laminated Body]

[0068] The method for producing the reflectance adjustment film of the present disclosure and the laminate of the present disclosure is not particularly limited. For example, the low-refractive-index film and the high-refractive-index film may be formed in this order on the substrate.

[0069] The method for forming the low refractive index film and the high refractive index film in the reflectivity adjustment film of the present disclosure is not particularly limited. For example, it is preferred to use a vacuum evaporation method, sputtering method, ion plating method or ion beam evaporation method classified as physical vapor deposition, or an atomic layer deposition method or plasma CVD method classified as chemical vapor deposition. Although the evaporation method has a fast film forming speed, it tends to form a film with low hardness (soft). Although the sputtering method has a slow film forming speed, it is easy to obtain a film with high hardness (hard). From the viewpoint of hardness, the reflectivity adjustment film of the present disclosure is preferably formed by sputtering to form the low refractive index film and the high refractive index film, respectively. In the method for manufacturing the reflectivity adjustment film of the present disclosure and the method for manufacturing the laminate of the present disclosure, as described above, in the low refractive index film forming step, the low refractive index film is formed by sputtering, and in the high refractive index film forming step, the high refractive index film is formed by sputtering.

[0070] In addition, for yttrium oxide (Y2O3) constituting the low refractive index film, in order to further replace part of the oxygen (O) atoms with nitrogen (N) atoms, for example, the film can also be formed by sputtering (reactive sputtering) in an atmosphere where nitrogen (N2) is added to argon (Ar).

[0071] In the low refractive index film forming step and the high refractive index film forming step in the method for manufacturing the reflectivity adjustment film of the present disclosure and the method for manufacturing the laminate of the present disclosure, the method for implementing sputtering is not particularly limited, and for example, it can be the same as or based on the conventional sputtering method.

[0072] In the low refractive index film forming process and the high refractive index film forming process, from the viewpoint of manufacturing efficiency, the film forming speed of the sputtering method is preferably not too slow, and from the viewpoint of film hardness, the film forming speed of the sputtering method is preferably not too fast.

[0073] [Example]

[0074] Hereinafter, examples of the present disclosure will be described, but the present disclosure is not limited to the following examples.

[0075] Materials used

[0076] Silicon dioxide (SiO2), yttrium oxide (Y2O3), and zirconium oxide (ZrO2) were used as targets for forming low-refractive-index films. Tantalum pentoxide (Ta2O5) was used as a target for forming high-refractive-index films. Glass was used as a substrate.

[0077] <Manufacturing of a Laminated Body Having a Reflectance Adjusting Film>

[0078] A stacked body having the reflectivity adjustment films of Examples 1 to 3 and Comparative Example 1 was manufactured by sputtering. In addition, the sputtering of the low refractive index film and the high refractive index film shown below was all carried out in an atmosphere of nitrogen (N2) added to argon (Ar). First, a target for forming the low refractive index film was sputtered onto one surface of the substrate so that the composition of yttrium oxide (Y2O3) became the composition shown in Table 1 below, thereby forming a low refractive index film (first layer, physical film thickness 250nm). Next, a target for forming the high refractive index film was sputtered onto the surface of the low refractive index film of the first layer to form a high refractive index film (second layer, physical film thickness 15nm). Next, a target for forming the low refractive index film was sputtered onto the surface of the high refractive index film of the second layer to form the composition of yttrium oxide (Y2O3) as shown in Table 1 below, thereby forming a low refractive index film (third layer, physical film thickness 30nm). Next, the target for forming the high refractive index film was sputtered onto the surface of the low refractive index film of the 3rd layer to form a high refractive index film (the 4th layer, a physical film thickness of 115nm). Finally, the target for forming the low refractive index film was sputtered onto the surface of the high refractive index film of the 4th layer so that the composition of yttrium oxide (Y2O3) became the composition shown in Table 1 below to form a low refractive index film (the 5th layer, a physical film thickness of 86nm). The laminated body having a reflectivity adjustment film obtained in this way was evaluated on a glass substrate. In addition, the low refractive index film formed by the above method is a film in which a portion of the yttrium (Y) atoms of yttrium oxide (Y2O3) is replaced by zirconium (Zr) atoms, and a portion of the oxygen (O) atoms of yttrium oxide (Y2O3) is replaced by nitrogen (N) atoms.

[0079] Evaluation Method

[0080] The low refractive index films formed as described above were measured for (1) refractive index according to the following procedure. In addition, the laminates formed with the reflectance adjustment films of Examples 1 to 3 and Comparative Example 1 were measured for (2) hardness and (3) average reflectance according to the following procedure.

[0081] (1) Refractive index

[0082] The refractive index of the low-refractive-index film was measured using a reflection spectroscopic film thickness meter (manufactured by Otsuka Electronics Co., Ltd., trade name: FE-3000) at a wavelength of 500 nm. The results are shown in Table 1 below.

[0083] (2) Hardness

[0084] A nanoindenter (manufactured by ELION IX Co., Ltd., trade name: ENT-1100a) was used to measure the hardness of the reflectivity adjustment film in the manufactured laminate. As an indenter, a Berkovich indenter was used to measure the nanoindentation hardness (hardness) when the reflectivity adjustment film was pressed into the laminate with a maximum load of 1.5 mN. Specifically, first, the indenter was loaded to the maximum load at a certain ratio and pressed into the sample. Then, the indenter was unloaded to a load of 0 at a certain ratio, and the indenter was separated from the sample. The displacement of the indenter during loading and unloading was recorded to determine the maximum load. Then, the contact projection area (the bottom area of the cone) of the contact portion when the indenter was pressed was determined. The nanoindentation hardness was determined by dividing the maximum load determined by the contact projection area. The results are shown in Table 1 below.

[0085] (3) Average reflectivity

[0086] Using optical simulation software (manufactured by TOHO TSUSHOO INC., trade name: ThinFilmView), simulated values of average reflectance in the visible light region (380 nm to 780 nm) were calculated. The results are shown in Table 1 below.

[0087]

Table 1

[0088]

[0089] As shown in Table 1, the hardness of Examples 1 to 3 was higher than that of Comparative Example 1. Furthermore, increasing the proportion of yttrium oxide (Y2O3) in the low-refractive-index film also increased the hardness. Furthermore, simulations revealed that varying the proportion of yttrium oxide (Y2O3) in the low-refractive-index film altered the average reflectivity.

[0090] In addition, the total light transmittance of the laminates of Examples 1 to 3, measured using an ultraviolet / visible / near-infrared spectrophotometer (manufactured by Shimadzu Corporation, trade name: SolidSpec-370), was 95%, indicating excellent transparency (not described in Table 1). Furthermore, the pencil hardness (based on the old JIS K5400) of the laminates of Examples 1 to 3 was 9H or higher, indicating high hardness (not described in Table 1). In addition, the low-refractive-index film formed by the method of this example is a film in which a portion of the oxygen (O) atoms of yttrium oxide (Y2O3) are substituted with nitrogen (N) atoms. However, even in a low-refractive-index film in which the oxygen (O) atoms of yttrium oxide (Y2O3) are not substituted with nitrogen (N) atoms, the hardness is increased by increasing the proportion of yttrium oxide (Y2O3) in the low-refractive-index film (not described in Table 1).

[0091] Furthermore, the present invention is not limited to the above-described embodiments, and any appropriate combination, modification, or selection can be made as needed without departing from the spirit of the present invention.

[0092] A part or all of the above-mentioned embodiments may be described as the following supplementary notes, but are not limited to the following contents.

[0093] (Note 1)

[0094] A reflectivity adjustment film for adjusting the reflectivity of light,

[0095] It is a stack of multiple films.

[0096] The plurality of films include a low refractive index film and a high refractive index film having a refractive index greater than that of the low refractive index film,

[0097] The low refractive index film is formed of a mixture containing silicon dioxide (SiO2) and yttrium oxide (Y2O3), wherein a portion of yttrium (Y) atoms in the yttrium oxide (Y2O3) are replaced by atoms of a 4A group element.

[0098] At least one of the films adjacent to the high-refractive-index film has a refractive index smaller than that of the high-refractive-index film.

[0099] (Note 2)

[0100] The reflectance adjustment film according to Supplementary Note 1, wherein

[0101] In the yttrium oxide (Y2O3), a part of the oxygen (O) atoms is further replaced by nitrogen (N) atoms.

[0102] (Note 3)

[0103] The reflectance adjustment film according to Supplementary Note 1 or 2, wherein

[0104] The content of yttrium oxide (Y2O3) in the low refractive index film is greater than 1.0 mol%.

[0105] (Note 4)

[0106] The reflectance adjustment film according to any one of Supplementary Notes 1 to 3, wherein

[0107] The atoms of the 4A group element in the low refractive index film are zirconium (Zr) atoms.

[0108] (Note 5)

[0109] A reflectivity adjustment film for adjusting the reflectivity of light,

[0110] It is a laminated film of multiple films.

[0111] The plurality of films include a low refractive index film and a high refractive index film having a refractive index greater than that of the low refractive index film,

[0112] At least one of the films adjacent to the high-refractive-index film has a refractive index smaller than that of the high-refractive-index film,

[0113] The reflectance adjustment film has a hardness of 6.0 GPa or more.

[0114] (Note 6)

[0115] The reflectance adjustment film according to any one of Supplementary Notes 1 to 5, wherein

[0116] The refractive index of the low-refractive-index film with respect to light having a wavelength of 500 nm is in the range of 1.47 to 1.58.

[0117] (Note 7)

[0118] The reflectance adjustment film according to any one of Supplementary Notes 1 to 6, wherein

[0119] The number of the plurality of films is 3 or more.

[0120] (Note 8)

[0121] The reflectance adjustment film according to any one of Supplementary Notes 1 to 7, wherein

[0122] The high refractive index film is formed of at least one selected from tantalum pentoxide (Ta2O5), niobium pentoxide (Nb2O5), titanium oxide (TiO2), zirconium oxide (ZrO2) and cerium oxide (CeO2).

[0123] (Note 9)

[0124] The reflectance adjusting film according to any one of Appendix 1 to 8, which is an antireflection film that prevents light reflection.

[0125] (Note 10)

[0126] A laminate comprising: a substrate and a reflectance adjustment film according to any one of Supplementary Notes 1 to 9 formed on at least one surface thereof.

[0127] (Note 11)

[0128] The laminate according to Supplementary Note 10, wherein

[0129] Among the plurality of films of the reflectance adjustment film, the film farthest from the substrate is the low refractive index film.

[0130] (Note 12)

[0131] The laminate according to Supplementary Note 10 or 11, wherein

[0132] The substrate is at least one of glass and resin.

[0133] (Note 13)

[0134] A method for producing a reflectance adjusting film according to any one of Supplementary Notes 1 to 9,

[0135] The method comprises a low refractive index film forming step of forming the low refractive index film and a high refractive index film forming step of forming the high refractive index film.

[0136] In the low-refractive-index film forming step, the low-refractive-index film is formed by a sputtering method, and in the high-refractive-index film forming step, the high-refractive-index film is formed by a sputtering method.

[0137] (Note 14)

[0138] A method for producing a laminate according to any one of Supplementary Notes 10 to 12,

[0139] The method includes the step of manufacturing the reflectance adjustment film on the substrate by the manufacturing method according to Supplementary Note 13.

[0140] This application claims the benefit of priority based on Japanese patent application No. 2023-075063, filed on April 28, 2023, the disclosure of which is incorporated herein in its entirety.

[0141] Description of Reference Numerals

[0142] 10.10a Reflectivity adjustment film

[0143] 11, 11a Low refractive index film

[0144] 12, 12a High refractive index film

[0145] 20 substrate

[0146] 30 Hard coating

[0147] 100, 100a laminate

Claims

1. A reflectivity adjustment film for adjusting the reflectivity of light. It is a stack of multiple films. The plurality of films include a low refractive index film and a high refractive index film having a refractive index greater than that of the low refractive index film, The low refractive index film is formed of a mixture containing silicon dioxide (SiO2) and yttrium oxide (Y2O3), wherein In the yttrium oxide (Y2O3), a portion of the yttrium (Y) atoms are replaced by atoms of the 4A group element. At least one of the films adjacent to the high-refractive-index film has a refractive index smaller than that of the high-refractive-index film.

2. The reflectance adjustment film according to claim 1, wherein In the yttrium oxide (Y2O3), a part of the oxygen (O) atoms is further replaced by nitrogen (N) atoms.

3. The reflectance adjustment film according to claim 1 or 2, wherein The content of yttrium oxide (Y2O3) in the low refractive index film is greater than 1.0 mol%.

4. The reflectance adjustment film according to any one of claims 1 to 3, wherein The atoms of the 4A group element in the low refractive index film are zirconium (Zr) atoms.

5. The reflectance adjustment film according to any one of claims 1 to 4, wherein The refractive index of the low-refractive-index film with respect to light having a wavelength of 500 nm is in the range of 1.47 to 1.

58.

6. The reflectance adjustment film according to any one of claims 1 to 5, wherein The high refractive index film is formed of tantalum pentoxide (Ta2O5). 7 . The reflectance adjusting film according to claim 1 , which is an antireflection film for preventing light reflection. 8 . A laminate comprising a substrate and the reflectance adjusting film according to claim 1 formed on at least one surface thereof.

9. The laminate according to claim 8, wherein Among the plurality of films of the reflectance adjustment film, a film farthest from the substrate is the low refractive index film.

10. A method for producing the reflectance adjusting film according to any one of claims 1 to 7, The method comprises a low refractive index film forming step of forming the low refractive index film and a high refractive index film forming step of forming the high refractive index film. In the low-refractive-index film forming step, the low-refractive-index film is formed by a sputtering method, and in the high-refractive-index film forming step, the high-refractive-index film is formed by a sputtering method.

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