Functional film, method for producing functional film, and layered body

Abstract

The present invention addresses the problem of providing: a functional film having improved abrasion resistance; a method for producing a functional film; and a layered body.　This functional film, which is disposed on a substrate, is characterized by containing an ionic-bonding compound and having an average MTF after Kanto loam soil rubbing testing of at least 70% as determined by steps (a) through (f).

Description

Functional film, method for producing functional film, and laminate

[0001] The present invention relates to a functional film, a method for producing the functional film, and a laminate, and more particularly to a functional film having improved abrasion resistance.

[0002] By further attaching a functional film to optical components such as lenses, antibacterial cover members, antifungal coating members, and mirrors, hydrophilicity or antifogging properties can be imparted.

[0003] Patent Document 1 discloses a technology relating to an anti-fogging element having a porous, transparent inorganic oxide film on its surface. By having a porous, transparent inorganic oxide film on its surface, the anti-fogging element can maintain anti-fogging properties for a long period of time.

[0004] Many functional films having hydrophilic or antifogging properties are formed by coating or vapor deposition. Functional films formed by coating have a problem of being more susceptible to abrasion than functional films formed by vapor deposition. On the other hand, functional films formed by vapor deposition are required to have further improved hydrophilic or antifogging properties.

[0005] Japanese Patent Application Publication No. 10-36144

[0006] The present invention has been made in view of the above problems and circumstances, and an object of the present invention is to provide a functional film with improved abrasion resistance, a method for manufacturing the functional film, and a laminate.

[0007] In order to solve the above problems, the present inventors have investigated the causes of the above problems and have found that a functional film with improved abrasion resistance can be provided by incorporating an ion-bonding compound into a functional film provided on a substrate and by increasing the average MTF value after a Kanto Loam soil abrasion test, measured by the procedures (a) to (f) described below, to 70% or more, thereby arriving at the present invention. That is, the above problems according to the present invention are solved by the following means.

[0008] 1. A functional film provided on a substrate, the functional film containing an ion-bonding compound, and characterized in that the average MTF value after a Kanto loam soil abrasion test measured by the following procedures (a) to (f) is 70% or more. Measurement procedure: (a) A functional film to be measured is formed on a test lens. (b) 10 g of Kanto loam soil specified in JIS Z 8901 is mixed with 100 mL of pure water to prepare muddy water, and the muddy water is soaked in a scrubbing brush. (c) Using the scrubbing brush, a muddy water of 1.0 N / cm is applied. ２ The test lens is rubbed for 100 seconds at a speed of one reciprocating stroke per second under a load of 0.015 mm. (d) The test lens obtained after the Kanto Loam soil rubbing test is wetted with mist water, and the black and white rectangular chart is photographed. (e) 24 straight lines are randomly selected from the obtained measurement image, and each straight line is quantified using a 256-level grayscale. (f) For each straight line, the maximum value of the 256-level grayscale numerical value is defined as Max, and the minimum value as Min, and the MTF value is calculated using the following formula: The arithmetic mean value of the MTF values ​​of the 24 straight lines is defined as the average MTF value. (Formula) MTF value (%) = {(Max - Min) / (Max + Min)} x 100

[0009] 2. The functional film according to claim 1, characterized in that it has an intermediate layer containing aluminum oxide.

[0010] 3. The functional film according to item 2, wherein the intermediate layer has a recessed portion structure.

[0011] 4. The functional film according to item 1, wherein the ion-bonding compound is either NaCl or NaF.

[0012] 5. The functional film according to item 1, characterized in that the average MTF value after the Kanto Loam soil abrasion test measured by the steps (a) to (f) is 80% or more.

[0013] 6. The functional film according to item 1, characterized in that the average MTF value after the Kanto Loam soil abrasion test measured by the steps (a) to (f) is 90% or more.

[0014] 7. The functional membrane according to item 1, characterized in that the functional membrane has a plurality of pores, and the average pore diameter is within the range of 0.1 to 50 nm.

[0015] 8. The functional membrane according to item 1, characterized in that the functional membrane has a hydrophilic layer, the hydrophilic layer further has a textured layer and a coating layer, and the textured layer contains particles of the ion-binding compound.

[0016] 9. The functional film according to claim 1, characterized in that the average MTF value after a storage test in an environment of 85°C and 85% RH, measured by the following procedures (g) to (k), is 70% or more. Measurement Procedure: (g) A functional film for measurement is formed on a test lens. (h) The test lens is stored in an environment of 85°C and 85% RH for 100 hours. (i) The test lens obtained after the storage test is wetted with mist water, and then a black and white rectangular chart is photographed. (j) 24 random straight lines are extracted from the obtained measurement image, and each straight line is quantified using a 256-level grayscale. (k) For each straight line, the maximum value of the 256-level grayscale is defined as Max, and the minimum value is defined as Min, and the MTF value is calculated using the following formula. The arithmetic mean of the MTF values ​​of the 24 straight lines is defined as the average MTF value. (Formula) MTF value (%) = {(Max - Min) / (Max + Min)} × 100

[0017] 10. The functional film according to claim 1, characterized in that the average MTF value after a storage test at 85°C in a dry environment, measured by the following steps (l) to (p), is 70% or more. Measurement Procedure: (l) A functional film for measurement is formed on a test lens. (m) The test lens is stored in a dry environment at 85°C for 100 hours. (n) The test lens obtained after the storage test is wetted with mist water, and then a black and white rectangular chart is photographed. (o) 24 random straight lines are extracted from the obtained measurement image, and each straight line is quantified using a 256-level grayscale. (p) For each straight line, the maximum value of the 256-level grayscale is defined as Max, and the minimum value is defined as Min, and the MTF value is calculated using the following formula. The arithmetic mean of the MTF values ​​of the 24 straight lines is defined as the average MTF value. (Formula) MTF value (%) = {(Max - Min) / (Max + Min)} × 100

[0018] 11. In the step (c), the load is 2.5 N / cm ２ 2. The functional film according to claim 1, wherein the average MTF value after a Kanto Loam soil rubbing test when the rubbing time is 250 seconds is 70% or more.

[0019] 12. The functional film according to item 1, characterized in that the functional film has a hydrophilic layer, and the ratio of the average thickness of the hydrophilic layer after the Kanto Loam soil abrasion test to the average thickness of the hydrophilic layer before the Kanto Loam soil abrasion test, measured by the following steps (q) to (t), is 40% or more. Measurement steps: (q) A functional film for measurement is formed on a test lens. (r) 10 g of Kanto Loam soil as specified in JIS Z 8901 is mixed with 100 mL of pure water to prepare muddy water, and the muddy water is soaked in a scrubbing brush. (s) Using the scrubbing brush, a pressure of 1.0 N / cm is applied. ２ The test lens is rubbed for 100 seconds at a speed of one reciprocation per second under a load of 100. (t) The thickness of the hydrophilic layer of the functional film is measured at 20 points on the surface of the functional film.

[0020] 13. In the step (s), the load is 2.5 N / cm ２13. The functional membrane described in item 12, wherein the ratio of the average thickness of the hydrophilic layer after the Kanto Loam soil rubbing test to the average thickness of the hydrophilic layer before the Kanto Loam soil rubbing test is 30% or more when the rubbing time is 250 seconds.

[0021] 14. A method for producing a functional film, wherein the functional film is the functional film described in paragraph 1, and the method comprises the steps of: forming a layer containing the ion-binding compound by a dry film formation method; forming pores in the formed layer containing the ion-binding compound; and heating the formed layer containing the ion-binding compound at a temperature higher than that during film formation.

[0022] 15. The method for producing a functional film according to item 14, wherein the heating step causes the size of pores in the layer containing the ion-bonding compound to become smaller than that before the heating step.

[0023] 16. A laminate having a substrate and a functional film, wherein the functional film is the functional film described in item 1.

[0024] 17. The laminate according to item 16, wherein the substrate is glass.

[0025] According to the above-mentioned means of the present invention, it is possible to provide a functional film with improved abrasion resistance, a method for producing the functional film, and a laminate.

[0026] The mechanism by which the effects of the present invention are manifested or the mechanism of action is not clear, but is speculated as follows.

[0027] As described above, functional films formed by vapor deposition are required to have further improved hydrophilicity or antifogging properties.

[0028] The functional film of the present invention has a porous structure with multiple pores. This is thought to increase the surface area that interacts with water molecules and improve hydrophilicity or anti-fogging properties. Furthermore, because the pores are not too large, the functional film is thought to have sufficient hardness and abrasion resistance.

[0029] Schematic cross-sectional view showing an example of the basic structure of the functional film of the present invention Schematic cross-sectional view showing an example of the layer structure of the functional film of the present invention Photograph of a cross section of a concave-convex layer of the functional film of the present invention observed with an electron microscope Rectangular chart used to measure the average MTF value Explanatory diagram of wetting a test lens with a functional film after a Kanto Loam soil abrasion test with water and photographing the rectangular chart Explanatory diagram of the image analysis region in a reference image or a measured image Explanatory diagram of the image analysis region in a reference image or a measured image Example of an image analysis operation screen Explanatory diagram of a line drawn within the image analysis region Example of an image analysis operation screen Example of operation screen Example of operation screen for image analysis Explanatory diagram showing an example of a method for producing a functional film (hydrophilic layer) of the present invention Explanatory diagram showing an example of a method for producing a functional film (hydrophilic layer) of the present invention Graph showing the spectral reflectance in the wavelength region of 400 to 780 nm of each functional film before and after performing step (V) Schematic cross-sectional views of each manufacturing step of a functional film of the present invention Schematic cross-sectional views of each manufacturing step of a functional film of the present invention Schematic cross-sectional views of each manufacturing step of a functional film of the present invention Schematic cross-sectional views of each manufacturing step of a functional film of the present invention Schematic cross-sectional views of each manufacturing step of a functional film of the present invention

[0030] The functional film of the present invention is a functional film provided on a substrate, contains an ion-binding compound, and is characterized in that the average MTF value after the Kanto Loam soil abrasion test measured by the above steps (a) to (f) is 70% or more. This feature is a technical feature common to or corresponding to the following embodiments.

[0031] In an embodiment of the present invention, it is preferable to have an intermediate layer containing aluminum oxide from the viewpoint of resistance to high temperatures and high humidity.

[0032] In an embodiment of the present invention, from the viewpoint of high temperature and high humidity resistance, the intermediate layer preferably has a recessed portion structure.

[0033] In an embodiment of the present invention, from the viewpoint of high temperature and high humidity resistance, the ion-bonding compound is preferably either NaCl or NaF, or both.

[0034] In an embodiment of the present invention, from the viewpoint of abrasion resistance, it is preferable that the average MTF value after the Kanto Loam soil abrasion test measured by the above procedures (a) to (f) is 80% or more.

[0035] In an embodiment of the present invention, from the viewpoint of abrasion resistance, it is preferable that the average MTF value after the Kanto Loam soil abrasion test measured by the above procedures (a) to (f) is 90% or more.

[0036] In an embodiment of the present invention, from the viewpoint of abrasion resistance, it is preferable that the functional film has a plurality of pores, and the average pore diameter is within the range of 0.1 to 50 nm.

[0037] In an embodiment of the present invention, from the viewpoint of achieving both high temperature / high humidity resistance and abrasion resistance, it is preferable that the functional film has a hydrophilic layer, the hydrophilic layer further has a textured layer and a coating layer, and the textured layer contains particles of the ion-binding compound.

[0038] In an embodiment of the present invention, from the viewpoint of high temperature and high humidity resistance, it is preferable that the average MTF value after a storage test under an environment of 85°C and 85% RH, measured by the above steps (g) to (k), is 70% or more.

[0039] In an embodiment of the present invention, from the viewpoint of high temperature and high humidity resistance, it is preferable that the average MTF value after a storage test at 85°C in a dry environment, measured by the above steps (l) to (p), is 70% or more.

[0040] In an embodiment of the present invention, from the viewpoint of abrasion resistance, the load in the step (c) is set to 2.5 N / cm ２ It is preferable that the average MTF value after the Kanto Loam soil rubbing test when the rubbing time is 250 seconds is 70% or more.

[0041] In an embodiment of the present invention, from the viewpoint of abrasion resistance, it is preferable that the functional film has a hydrophilic layer, and the ratio of the average thickness of the hydrophilic layer after the Kanto Loam soil abrasion test to the average thickness of the hydrophilic layer before the Kanto Loam soil abrasion test, measured by the steps (q) to (t), is 40% or more.

[0042] In an embodiment of the present invention, from the viewpoint of abrasion resistance, the load is set to 2.5 N / cm in the step (s). ２ When the rubbing time is 250 seconds, it is preferable that the ratio of the average thickness of the hydrophilic layer after the Kanto Loam soil rubbing test to the average thickness of the hydrophilic layer before the Kanto Loam soil rubbing test is 30% or more.

[0043] The method for producing a functional film of the present invention is a method for producing the functional film, and is characterized by comprising the steps of: forming a layer containing the ion-binding compound by a dry film formation method; forming pores in the formed layer containing the ion-binding compound; and heating the formed layer containing the ion-binding compound at a temperature higher than that during film formation.

[0044] In an embodiment of the present invention, from the viewpoint of abrasion resistance, it is preferable that the heating step reduces the size of the pores in the layer containing the ionically bonding compound compared to before the heating step.

[0045] The laminate of the present invention is characterized by being a laminate having a substrate and the functional film.

[0046] In an embodiment of the present invention, the substrate is preferably glass from the viewpoint of transparency.

[0047] The present invention, its components, and embodiments and modes for carrying out the present invention will be described in detail below. In this application, the symbol "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0048] 1. Overview of the Functional Film The functional film of the present invention is a functional film provided on a substrate, contains an ion-binding compound, and is characterized in that the average MTF value after the Kanto Loam soil abrasion test measured by the above procedures (a) to (f) is 70% or more. Details of the procedure for measuring the average MTF value will be described later.

[0049] Fig. 1 is a cross-sectional schematic diagram showing an example of the basic structure of the functional film of the present invention. Laminate 10 has functional film 1 and substrate 2, and functional film 1 is provided on substrate 2. Fig. 1 is an example of the functional film of the present invention, and is not limited to this layer structure. Note that another functional film may be present between functional film 1 and substrate 2. Furthermore, another functional film may be present on the surface of functional film 1 opposite substrate 2, as long as the effects of the present invention can be sufficiently obtained.

[0050] Fig. 2 is a cross-sectional schematic diagram showing an example of the basic structure of the functional membrane of the present invention. The laminate 11 has a functional membrane 1 and a substrate 2. The functional membrane 1 has a two-layer structure, including a hydrophilic layer 3 and an intermediate layer 4. Fig. 2 shows an example of the functional membrane of the present invention, and the layer structure is not limited to this. Note that another functional membrane may be present between the hydrophilic layer 3 and the intermediate layer 4. The intermediate layer is preferably provided when the hydrophilic layer contains a specific ion-binding compound.

[0051] The functional film of the present invention may be provided directly on a substrate, or may be provided on a substrate via a photocatalytic layer, a reflectance adjusting layer, a high refractive index layer, or the like.

[0052] 2. Structure of the Functional Membrane The hydrophilic layer and the intermediate layer will be described below. When the functional membrane has a single layer structure, the functional membrane is composed of only the hydrophilic layer.

[0053] (1) Hydrophilic Layer The hydrophilic layer according to the present invention contains an ionically bondable compound. The ionically bondable compound dissociates into positively or negatively charged ions. The dissociated ions and water molecules are likely to bond by hydrogen bonds. Therefore, by including an ionically bondable compound in the hydrophilic layer, the hydrophilicity or anti-fogging properties can be improved.

[0054] The ionic bonding compound is preferably an inorganic salt. The element contained in the inorganic salt is preferably an alkali metal element or an alkaline earth metal element. Examples of alkali metal elements or alkaline earth metal elements include Li (lithium), Na (sodium), K (potassium), Rb (rubidium), Cs (cesium), Fr (francium), Be (beryllium), Mg (magnesium), Ca (calcium), Sr (strontium), Ba (barium), and Ra (radium).

[0055] From the viewpoint of high temperature and high humidity resistance of the hydrophilic layer, the element contained in the inorganic salt is preferably an alkali metal element, and particularly preferably Na (sodium) or Mg (magnesium).

[0056] The solubility of the ion-binding compound in water at 20°C is preferably 0.5 g / 100 mL or more. This allows the hydrophilic layer to absorb moisture when exposed to the atmosphere or water vapor after dry film formation. This is thought to result in the formation of multiple pores in the hydrophilic layer, forming a porous structure.

[0057] Examples of inorganic salts having a solubility of 0.5 g / 100 mL or more include LiCl (solubility: 76.9 g / 100 mL (20° C.)), NaCl (solubility: 35.9 g / 100 mL (20° C.)), MgCl ２ ・6H ２ O (solubility: 54.3g / 100mL (20℃)), KCl (solubility: 34.0g / 100mL (20℃)), CaCl ２ (Solubility: 74.5g / 100mL (20℃)), Na ２ CO ３ (solubility: 22 g / 100 mL (20° C.)), NaF (solubility: 4.06 g / 100 mL (20° C.)), etc.

[0058] Among inorganic salts containing alkali metal elements or alkaline earth metal elements, those having a solubility within a suitable range include NaCl, NaF, MgCl ２ ・6H ２ Examples include O.

[0059] The average particle size of the ion-binding compound contained in the hydrophilic layer is preferably within a range of 10 to 1,000 nm, and can be measured using, for example, an electron microscope "S-4800" (Hitachi High-Tech Corporation) or an atomic force microscope "L-Trace SII" (Nano Technology Corporation).

[0060] The ion-bonding compound may be contained alone or in combination of two or more kinds. The hydrophilic layer may also contain silicon oxide.

[0061] The hydrophilic layer is preferably formed by dry film formation, which makes it easy to form a fine uneven structure with metal particles uniformly distributed, and a porous structure.

[0062] Examples of dry film formation include vapor deposition methods such as vacuum vapor deposition, ion beam vapor deposition, ion plating, and ion-assisted vapor deposition. Hereinafter, in the present invention, ion-assisted vapor deposition is also referred to as "IAD method." Examples of dry film formation include sputtering methods such as sputtering, ion beam sputtering, and magnetron sputtering. Among these, vacuum vapor deposition, IAD, and sputtering are preferred. Resistance heating type vacuum vapor deposition is particularly preferred.

[0063] The thickness of the hydrophilic layer is preferably within the range of 0.1 to 100 nm.

[0064] (2) Intermediate layer In view of high temperature and high humidity resistance, the functional film of the present invention may have an intermediate layer when the ion-binding compound is a specific compound. When a reflectance adjusting layer, a photocatalyst layer, or the like described below is provided on the substrate, it is preferable to provide an intermediate layer on the reflectance adjusting layer, the photocatalyst layer, or the like. For example, when the hydrophilic layer contains a sodium salt as the ion-binding compound, providing an intermediate layer is thought to prevent sodium from diffusing and disappearing from the hydrophilic layer.

[0065] The intermediate layer preferably contains an inorganic compound as a main component. The inorganic compound is not particularly limited, and examples thereof include Ta ２ O ５ -TiO２ "OA600" (Canon Optron Inc.), HfO ２ , Y ２ O ３ , LaF, CeF, Al ２ O ３ , ZnS, SiO ２ In particular, from the viewpoint of hydrophilicity, the inorganic compound is Al ２ O ３ It is preferable that:

[0066] The intermediate layer can be formed by the same method as that for forming the hydrophilic layer.

[0067] When a photocatalytic layer is provided on a substrate, it is preferable to form recesses by etching after dry film formation. By forming recesses, the photocatalytic effect of the underlying photocatalytic layer can be effectively exhibited.

[0068] The average diameter of the recesses is preferably within a range of 10 to 1,000 nm. The average diameter can be calculated, for example, using a scanning electron microscope "S-4800" (manufactured by Hitachi High-Technologies Corporation) or a scanning probe microscope "L-Trace SII" (manufactured by Nano Technology Co., Ltd.). The thickness of the intermediate layer is preferably within a range of 0.1 to 100 nm.

[0069] 3. Composition Analysis of Functional Films Below is an example of specific conditions for XPS analysis that can be applied to the composition analysis of functional films. ・Analysis equipment: X-ray photoelectron spectrometer "Quantera SXM" (manufactured by ULVAC-PHI, Inc.) ・X-ray source: Monochromated Al-Kα 15 kV-25 W ・Sputter ions: Ar (2 kV) ・Depth profile: SiO ２ Measurements are repeated at predetermined thickness intervals using the converted sputtering thickness to obtain a depth profile in the depth direction. The thickness interval is set to 2.5 nm. This allows data to be obtained every 2.5 nm in the depth direction. Quantification: The background is determined using the Shirley method, and quantification is performed using the relative sensitivity factor method from the obtained peak area. Data processing is performed using the analysis software "MultiPak" (manufactured by ULVAC-PHI, Inc.).

[0070] X-ray photoelectron spectroscopy (XPS) is a method for analyzing the constituent elements of a sample by irradiating the sample with X-rays and measuring the energy of the resulting photoelectrons. The element concentration distribution curve in the thickness direction of a functional film can be measured by combining measurement of the surface element composition of the sample with ion sputtering using a rare gas such as argon (Ar), exposing the interior of the functional film from its surface and sequentially analyzing the surface composition. Hereinafter, the element concentration distribution curve in the thickness direction is also referred to as the "depth profile."

[0071] A distribution curve obtained by XPS depth profile measurement can be created, for example, with the atomic concentration ratio of each element (unit: atomic %) on the vertical axis and the etching time (sputtering time) on the horizontal axis.

[0072] In the element distribution curve with the horizontal axis representing the etching time, the etching time roughly correlates with the distance from the surface in the thickness direction of the functional film. Therefore, the "distance from the surface in the thickness direction of the functional film" can be the distance from the surface of the functional film calculated from the relationship between the etching rate and etching time used in the XPS depth profile measurement.

[0073] The sputtering method used in the XPS depth profile measurement is a rare gas ion sputtering method using argon (Ar) as an etching ion species. The etching rate is determined by the etching of a SiO film having a known thickness. ２ The etching depth can be measured using a thermal oxide film. ２ It can be expressed as a thermal oxide film equivalent value.

[0074] By the composition analysis described above, for example, it is possible to observe the change in the composition of the functional film immediately after the functional film is formed and after it has been placed in a high-temperature, high-humidity environment (85° C., 85% RH) for a long period of time (234 hours).

[0075] 4. Porous Structure of Functional Film The functional film of the present invention preferably has a porous structure having a plurality of pores, and in particular, it is preferable that the hydrophilic layer has a porous structure, which can increase the surface area that interacts with water molecules and improve hydrophilicity or anti-fogging properties.

[0076] In particular, the ion-binding compound contained in the hydrophilic layer is preferably particulate. Furthermore, it is preferable that the particulate ion-binding compound exists as large particles or islands formed by agglomeration of multiple particles. The presence of the ion-binding compound in such a shape allows for a porous structure while maintaining high film strength. In other words, abrasion resistance and hydrophilicity or anti-fogging properties can be achieved simultaneously. Furthermore, the use of multiple ion-binding compounds allows for the superposition of unevenness of multiple sizes. For example, NaCl easily produces particles with diameters in the range of 5 to 200 nm, and NaF easily produces particles with diameters in the range of 3 to 50 nm. The particle size is preferably within the range of 1 to 500 nm.

[0077] Fig. 3 is a cross-sectional schematic diagram showing an example of the layer structure of the functional film of the present invention. Fig. 4 is an electron microscope photograph of a cross section of the textured layer of the functional film of the present invention. The functional film 1 shown in Fig. 3 is configured to include at least a hydrophilic layer. The hydrophilic layer has a textured layer 5 containing particles of the ion-binding compound and a coating layer 6. However, the present invention is not limited thereto. The hydrophilic layer does not necessarily have to have the coating layer 6, and may have only the textured layer 5.

[0078] The uneven layer is a layer that serves as a prototype or base for the outermost surface of a functional film having a fine uneven structure, and is preferably a layer having particulate or island-like convex shapes. The uneven layer is formed, for example, in an intermediate step included in the manufacturing process of a functional film, by initially forming or arranging an ionic compound (e.g., sodium chloride crystal particles) in the form of particles on the surface of a lower layer (e.g., a substrate or a reflectance adjusting layer) that will ultimately serve as the base for the uneven layer. Thereafter, a coating layer (e.g., SiO ２ It is preferable that the particles are covered with a layer (layer) to form a layer having a shape with an uneven structure containing the particles.

[0079] Various methods can be used to form or arrange the ion-bonding compound in a particulate form. For example, first, a layer consisting of particle components or particle aggregates and not yet having a predetermined fine uneven structure is formed by a dry film formation method as a "precursor of an uneven layer having an uneven structure." Thereafter, it is preferable to expose the layer to an atmospheric pressure environment or a moisture-containing atmospheric environment to separate and isolate the particles contained in the layer.

[0080] Although not shown in Figure 3, the ion-binding compound is preferably dispersed and contained in the coating layer as well. The layer of the ion-binding compound formed in the coating layer is hereinafter also referred to as the "ion-binding compound layer." The ion-binding compound layer in the coating layer does not necessarily need to form a large uneven structure, so it does not necessarily need to be formed or arranged in the form of large particles, and is preferably formed in the form of extremely small particles. The thickness of the ion-binding compound layer is preferably smaller than the thickness of the uneven layer, i.e., the diameter of the particles in the uneven layer.

[0081] In the present invention, the term "pore" refers to the space (gap) between the materials forming the hydrophilic layer. For example, the pore refers to the gap between particles of the ion-binding compound found in the uneven layer 5, as shown in FIG. 4. The coating layer 6 also preferably has pores, and as shown in FIG. 3, it preferably has pores 6c that are shaped to connect to the interior of the coating layer 6. The coating layer 6 has pores 6c, which facilitates binding of the ion-binding compound with water molecules. The pores 6c preferably communicate with the uneven layer 5 or other layers of the functional membrane.

[0082] In the present invention, since the pores are not too large, the functional membrane can have sufficient hardness and abrasion resistance. That is, by having pores of an appropriate size, the functional membrane of the present invention can achieve both hydrophilicity and abrasion resistance.

[0083] The average pore diameter is preferably in the range of 0.1 to 100 nm, and more preferably in the range of 0.1 to 50 nm. The pore diameter can be measured, for example, from images of a scanning electron microscope (SEM) or a transmission electron microscope (TEM). An arbitrary particle is selected from the SEM image and used as a reference particle. The distances between the reference particle and the five particles closest to it are measured. The arithmetic mean value of the measured values ​​is used as the "pore diameter of the reference particle." Ten arbitrary reference particles are selected from the SEM image, and the arithmetic mean value of the pore diameters of these reference particles is used as the "average pore diameter."

[0084] After forming a functional film using a dry film formation method, a porous structure can be formed by exposing the functional film to an atmospheric pressure environment or a moist environment through an aging process. However, from the perspective of achieving both hydrophilicity and abrasion resistance, it is desirable to optimize the pores formed by this method to be even smaller. Therefore, after forming the porous structure, the functional film is preferably heated at a temperature higher than that used during film formation. Heating can reduce the pore size.

[0085] 5. Finely textured structure of functional film The functional film of the present invention preferably has a finely textured structure on the surface or inside. Furthermore, in the textured structure, the mutual positional relationship and shape of each of the multiple textured portions preferably have randomness to the extent that diffracted light is not generated. Here, "randomness" refers to the absence of regularity in terms of identity or periodicity. By having randomness, visibility can be improved. Furthermore, hydrophilicity or anti-fogging properties can be improved.

[0086] In the present invention, the "concave and recess portion" includes not only a layered portion having concave and convex portions, but also a particle-like portion that does not appear to be a layer. In the present invention, the "degree to which diffracted light is not generated" means that diffracted light is not generated due to interference between multiple reflected lights from the concave and convex portions or interference between incident light and reflected light.

[0087] In the present invention, as will be described later, a fine uneven structure is formed by dry film formation, which results in an irregular (random) fine structure, making it possible to suppress diffracted light.

[0088] The presence or absence of diffracted light can be confirmed, for example, by the following method: A sample of the functional film is placed between a helium-neon laser and a screen, and light is irradiated onto the screen through the sample. The presence or absence of diffracted light from the light irradiated onto the screen is visually confirmed.

[0089] In the present invention, the term "fine uneven structure" refers to a structure having a plurality of fine uneven shapes that are large enough to exhibit the function of a functional film. More specifically, it refers to a structure having an uneven shape in which the average height of the convex portions is 1 μm or less, based on the lowest surface of the concave portions, that is, the average depth of the concave portions is 1 μm or less.

[0090] (1) Arithmetic mean roughness Ra In the present invention, the "arithmetic mean roughness Ra of the convex portions" refers to the arithmetic mean value of the roughness of 10 or more convex portions in a vertical cross section (cross section in the thickness direction) of the fine uneven structure. The roughness of the convex portions can be measured using, for example, a scanning probe microscope "L-Trace SII" (manufactured by Nano Technology Co., Ltd.). The arithmetic mean roughness Ra of the convex portions is preferably in the range of 2 to 50 nm, more preferably in the range of 10 to 40 nm, and even more preferably in the range of 15 to 30 nm.

[0091] (2) Maximum Height In the present invention, the "maximum height of the convex portions" refers to the maximum value of the distance from the bottom surface to the top surface (top surface) of 10 or more convex portions in a vertical cross section. The height of the convex portions can be measured using, for example, a scanning probe microscope "L-Trace SII" (manufactured by Nano Technology Co., Ltd.). The maximum height of the convex portions is preferably in the range of 10 to 500 nm, more preferably in the range of 50 to 200 nm, and even more preferably in the range of 70 to 150 nm.

[0092] (3) Average Diameter In the present invention, the "average diameter of the convex portions" refers to the arithmetic average value of the diameters of 10 or more convex portions when the fine concave-convex structure is viewed from above, that is, when the entire fine concave-convex structure is photographed from above with an electron microscope and the photograph is observed. The diameter of the convex portions can be measured using, for example, an electron microscope "S-4800" (manufactured by Hitachi High-Tech Corporation). The average diameter of the convex portions is preferably in the range of 10 to 1000 nm, more preferably in the range of 30 to 500 nm, and even more preferably in the range of 50 to 200 nm.

[0093] The arithmetic mean roughness Ra, maximum height, and average diameter of the convex portions can be controlled by using the method for producing a functional film of the present invention described below. Specifically, they can be controlled by forming the functional film by a dry film formation method.

[0094] 6. Physical Properties of Functional Film (1) Average MTF Value In the present invention, the "average MTF value" refers to a value obtained by measuring MTF (Modulation Transfer Function) according to the following procedure.

[0095] In the present invention, the average MTF value is measured with a functional film formed on a test lens. The functional film is formed directly on the test lens, or a cover is attached to the test lens and the film is formed directly on the cover. The cover is preferably made of a resin, and the resin is preferably an acrylic resin, polycarbonate, or the like.

[0096] In the following measurements, MTF analysis is performed on the test lenses with functional films after the Kanto Loam soil abrasion test. The average MTF value obtained by MTF analysis represents the degree of hydrophilicity or anti-fogging properties of the functional film. A functional film with high abrasion resistance remains attached to the test lens even after the Kanto Loam soil abrasion test, and therefore shows a relatively high average MTF value. On the other hand, a functional film with low abrasion resistance peels off from the test lens after the Kanto Loam soil abrasion test, and therefore shows a relatively low average MTF value of the test lens alone. In other words, the higher the average MTF value, the higher the abrasion resistance and the higher the hydrophilicity or anti-fogging properties of the functional film can be determined to be.

[0097] The average MTF value is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more.

[0098] Measurement procedure: (a) A functional film to be measured is formed on a test lens. (b) 10 g of Kanto loam soil as specified in JIS Z 8901 is mixed with 100 mL of pure water to prepare muddy water, which is then soaked in a scrubbing brush. (c) Using the scrubbing brush, a pressure of 1.0 N / cm is applied. ２ The test lens is rubbed for 100 seconds at a speed of one reciprocating stroke per second under a load of 0.015 mm. (d) The test lens obtained after the Kanto Loam soil rubbing test is wetted with mist water, and the black and white rectangular chart is photographed. (e) 24 straight lines are randomly selected from the obtained measurement image, and each straight line is quantified using a 256-level grayscale. (f) For each straight line, the maximum value of the 256-level grayscale numerical value is defined as Max, and the minimum value as Min, and the MTF value is calculated using the following formula: The arithmetic mean value of the MTF values ​​of the 24 straight lines is defined as the average MTF value. (Formula) MTF value (%) = {(Max - Min) / (Max + Min)} x 100

[0099] (1.1) Preparation of test lens (Procedure a) A glass material "H-ZLaF55F" (manufactured by CDGM) is processed as a substrate for an in-vehicle lens to obtain a test lens. The test lens is cleaned for 600 seconds using a UV ozone device (manufactured by Technovision).

[0100] A functional film is formed on the entire surface of the test lens on the S1 surface by the functional film manufacturing method described below, to obtain a test lens with a functional film. The effective diameter of the S1 surface of the test lens is 12 mm, and the radius of curvature is 14 mm. The test lens also consists of the S1 surface on the object side and the S2 surface on the image side. As mentioned above, if a cover is attached to the test lens, the functional film is formed on the cover. This case is also included in "forming a film on the test lens."

[0101] (1.2) Kanto Loam Soil Scraping Test (Procedures b and c) In the Kanto Loam Soil Scraping Test, the functional film side of the test lens is rubbed with a scrubbing brush containing muddy water. This test allows evaluation of outdoor abrasion resistance. In this test, the scrubbing brush is placed below the scratch resistance test device and the lens is placed above the scratch resistance test device, and the scrubbing test is performed by sliding the lens.

[0102] (Preparation of Muddy Water) 10 g of Kanto loam soil specified in JIS Z 8901 and 100 mL of pure water were mixed to prepare 10% by mass of muddy water.

[0103] (Mounting of Lens) A lens unit equipped with a test lens with a functional film is fixed to a lens unit mounting jig, which is then mounted on the top of a scratch resistance test device.

[0104] (Load adjustment) The load applied to the lens at the position where the lens and the scrubbing brush come into contact is 1.0 N / cm. ２ Adjust using a weight or the like so that

[0105] (Attaching the scrub brush) The scrub brush is thoroughly immersed in the container containing the prepared muddy water and then removed. This causes the particles of the Kanto loam soil to adhere to the bristles of the scrub brush. The scrub brush is then attached to the bottom of the scratch resistance test equipment. A new or nearly new scrub brush with evenly spaced bristles is used.

[0106] (Rubbing test) 1.0 N / cm ２ The lens is moved back and forth for 100 seconds (100 strokes) at a load of 100 mm and a speed of one stroke per second. Note that "one stroke per second" refers to the speed at which a specific point on the scrubbing brush moves back and forth from one end of the lens to the other in one second. The muddy water is then washed off the lens with water, and the lens is wiped dry to obtain a test lens with a functional film that has undergone the Kanto Loam soil abrasion test.

[0107] (1.3) Photographing the rectangular chart (Step d) After the Kanto Loam soil abrasion test, the test lens with the functional film was wetted with mist water, and the rectangular chart was photographed. The distance between the test lens and the rectangular chart was 15 cm.

[0108] (Preparation of Rectangle Chart) A rectangle chart (Fig. 5) is prepared, in which black and white rectangles each 5 mm wide are regularly arranged on an A4 sheet of paper.

[0109] (Photographing a rectangular chart: measurement image) Figure 6 is an explanatory diagram of wetting a test lens with a functional film after the Kanto Loam soil abrasion test with mist water and photographing a rectangular chart. As shown in Figure 6, a portion of the rectangular chart 12 is hollowed out, and the tip 13 of a "Takumi Damashii" airbrush (0.3 mm diameter) is attached to the hollowed-out area. The rectangular chart 12 and test lens 14 are positioned perpendicular to the ground and 15 cm apart. Mist water 15 is sprayed with an airbrush for 30 seconds onto the test lens with a functional film after the Kanto Loam soil abrasion test. The rectangular chart is photographed with the test lens with a functional film after the Kanto Loam soil abrasion test in this wet state. The photograph is taken 3 seconds after the spraying of mist water onto the test lens has finished.

[0110] (Photographing a rectangular chart: reference image) A rectangular chart is photographed on a test lens with a functional film that is not wet and has not yet been subjected to the Kanto Loam soil abrasion test, and this is used as a reference image. That is, after the above step (a), a rectangular chart is photographed without performing steps (b) and (c). The arrangement of the rectangular chart and test lens is the same as when photographing the measurement image. As will be described in more detail later, by comparing the reference image with the measurement image, the degree of hydrophilicity or anti-fogging properties of the functional film can be evaluated.

[0111] (1.4) MTF analysis (steps e and f): The reference image or the measurement image is displayed in 256 grayscale levels, and the degree to which black and white can be clearly distinguished is analyzed. The clearer the distinction between black and white, the less the influence of wear and the more effectively the functional film can be determined to be exerted.

[0112] The reference image or measurement image is cut into a rectangle or a circle so that the center of the image coincides with the center of the rectangular chart and so that the edge of the image abuts at least a part of the edge of the rectangular chart. In the obtained reference image or measurement image 20, a rectangular region extending 50% from the center 21 is used as the region 22 for image analysis, as shown in Fig. 7. For example, if the field of view of the lens is circular rather than rectangular, as in the case of a fisheye lens, a circular region extending 50% from the center 21 is used as the region 22 for image analysis, as shown in Fig. 8.

[0113] Image analysis is performed on a central 50% area of ​​the obtained reference image or measurement image using the image processing software "Image J" (available from https: / / imagej.nih.gov / ij / ).

[0114] Open the reference image or measurement image in the image processing software "Image J" (see FIG. 9), and draw 24 arbitrary straight lines perpendicular to the black and white line chart within the image analysis region. FIG. 10 is a diagram showing a rectangular image analysis region 50% from the center of an actual reference image or measurement image. The image analysis region 22 is further divided into four equal parts as shown by the dotted lines. Then, draw six arbitrary straight lines within each of the four equal parts. When the reference image or measurement image is circular, the image analysis region is divided into four equal parts, as in the case of a rectangle, and draw six arbitrary straight lines within each of the four equal parts. The line dividing the image analysis region into four equal parts (the dotted line in FIG. 10) is a straight line passing through the center of the image analysis region.

[0115] The length of the line is not limited, but it must cross at least seven black or white boundary lines. Note that "crossing" here means that the line passes through two opposing long sides of the rectangle (black and white boundary lines). As shown in FIG. 10, line a23 and line b24 cross at least seven black or white boundary lines. On the other hand, line c25 does not cross any black or white boundary lines. Therefore, line c25 does not satisfy the condition and is not a line to be used in the analysis.

[0116] In the rectangular chart shown in Figure 5, all of the black and white boundary lines are straight lines and are parallel or perpendicular to each other. On the other hand, as shown in Figure 10, in the rectangular chart in the reference image or measurement image, the black and white boundary lines are not necessarily all straight lines, but are partially curved. Therefore, in the present invention, "a direction perpendicular to the black and white straight line chart" refers to a direction perpendicular to at least one of the black or white boundary lines. In other words, line a23 and line b24 each cross seven or more black or white boundary lines, but intersect perpendicularly with at least one of those boundary lines.

[0117] In the reference image or measurement image, the portion corresponding to the 24 drawn straight lines is extracted, and the profile of the black or white pattern of the straight lines is obtained and output as a numerical value. Specifically, in the image processing software "Image J," "Plot Profile" is selected from the "Analyze" button (see Figures 11 and 12). Furthermore, "List" is selected for the obtained profile (see Figure 13). The numerical value obtained here is the value when the black or white pattern of the straight lines is expressed in 256 grayscale levels.

[0118] The value expressed by the following formula, where the maximum value is Max and the minimum value is Min, of the obtained numerical values, is taken as the "MTF value." The MTF value indicates how clearly black and white can be distinguished. When black and white are clearly and completely distinguishable, that is, when Max = 255 and Min = 0, the MTF value is 100%.

[0119] (Formula) MTF value (%) = {(Max - Min) / (Max + Min)} × 100

[0120] The MTF value is calculated for each of the 24 straight lines, and the arithmetic mean value of these values ​​is defined as the "average MTF value."

[0121] The abrasion resistance of the functional film can be evaluated by comparing a reference image of the functional film that was not wetted with water before the Kanto Loam soil abrasion test with a measurement image of the functional film after wetting with water. The hydrophilicity or anti-fogging properties of the functional film can also be evaluated. The smaller the difference between the average MTF value of the reference image and the average MTF value of the measurement image, the higher the abrasion resistance of the functional film and the higher its hydrophilicity or anti-fogging properties can be evaluated.

[0122] (1.5) Storage Test in High-Temperature Environments The functional film of the present invention preferably has an average MTF value of 70% or more after a storage test (1) in an environment of 85°C and 85% RH, as measured by the following procedures (g) to (k). Also, it is preferable that the average MTF value of the functional film of the present invention has an average MTF value of 70% or more after a storage test (2) in an environment of 85°C and dry, as measured by the following procedures (l) to (p).

[0123] Procedure for measuring the average MTF value after storage test (1): (g) A functional film for measurement is formed on a test lens. (h) The test lens is stored for 100 hours in an environment of 85°C and 85% RH. (i) The test lens obtained after the storage test is wetted with mist water, and then a black and white rectangular chart is photographed. (j) 24 random straight lines are extracted from the obtained measurement image, and each line is quantified using a 256-level grayscale. (k) For each straight line, the maximum value of the 256-level grayscale is defined as Max, and the minimum value is defined as Min, and the MTF value is calculated using the following formula. The arithmetic mean value of the MTF values ​​of the 24 straight lines is defined as the average MTF value. (Formula) MTF value (%) = {(Max - Min) / (Max + Min)} x 100

[0124] Procedure for measuring the average MTF value after storage test (2): (l) A functional film for measurement is formed on a test lens. (m) The test lens is stored at 85°C in a dry environment for 100 hours. (n) The test lens obtained after the storage test is wetted with mist water, and then a black and white rectangular chart is photographed. (o) 24 random straight lines are extracted from the obtained measurement image, and each straight line is quantified using a 256-level grayscale. (p) For each straight line, the maximum value of the 256-level grayscale is defined as Max, and the minimum value as Min, and the MTF value is calculated using the following formula. The arithmetic mean value of the MTF values ​​of the 24 straight lines is defined as the average MTF value. (Formula) MTF value (%) = {(Max - Min) / (Max + Min)} x 100

[0125] In this measurement procedure, a storage test is performed instead of the Kanto Loam soil rubbing test. Except for the storage test, the procedure is the same as above.

[0126] When the average MTF value is 70% or more, it can be determined that the functional film of the present invention has high hydrophilicity or antifogging properties even after storage in a high-temperature environment.

[0127] "85°C, dry environment" refers to an environment that can be adjusted by setting the temperature to 85°C using a small high-temperature chamber "ST-120" (manufactured by Espec Corporation).

[0128] (1.6) High-load rubbing test The functional film of the present invention was subjected to high-load rubbing test in the above procedure (c) at a load of 2.5 N / cm ２ It is preferable that the average MTF value after the Kanto Loam soil rubbing test when the rubbing time is 250 seconds is 70% or more.

[0129] When the average MTF value is 70% or more, the functional film of the present invention can be judged to have high abrasion resistance and high hydrophilicity or anti-fogging properties even when subjected to a high-load rubbing test under more severe conditions.

[0130] (2) Residual rate after rubbing test The functional film of the present invention preferably has a ratio of the average thickness of the hydrophilic layer after the Kanto Loam soil rubbing test to the average thickness of the hydrophilic layer before the Kanto Loam soil rubbing test, measured by the following procedures (q) to (t), of 40% or more. In other words, from the viewpoint of abrasion resistance, the functional film of the present invention preferably has a high residual rate of the hydrophilic layer on its surface after the rubbing test.

[0131] Measurement procedure: (q) A functional film to be measured is formed on a test lens. (r) 10 g of Kanto loam soil as specified in JIS Z 8901 is mixed with 100 mL of pure water to prepare muddy water, and the muddy water is soaked in a scrubbing brush. (s) Using the scrubbing brush, a pressure of 1.0 N / cm is applied. ２ The test lens is rubbed for 100 seconds at a speed of one reciprocation per second under a load of 100. (t) The thickness of the hydrophilic layer of the functional film is measured at 20 points on the surface of the functional film.

[0132] The 20 points at which the thickness of the hydrophilic layer is measured are as follows: The point on the surface of the functional film that overlaps with the center of the test lens when viewed from directly above is defined as the center point of the functional film. An arbitrary straight line is drawn on the surface of the functional film, passing through the center point of the functional film. The measurement point is any point on this straight line, provided that there is a distance of at least 0.5 mm between adjacent measurement points.

[0133] The thickness of the functional film is measured at the above 20 locations. If the functional film is composed of only a hydrophilic layer, the thickness of the functional film is the same as the thickness of the hydrophilic layer. If the functional film has layers other than the hydrophilic layer, the thickness of the hydrophilic layer is calculated by subtracting the thickness of the other layers from the thickness of the functional film. If the thickness of the functional film is thinner than the sum of the thicknesses of the other layers, no hydrophilic layer remains, and the remaining rate is considered to be 0%.

[0134] The arithmetic mean value of the thicknesses of the hydrophilic layer at the 20 locations was taken as the average thickness of the hydrophilic layer. The average thicknesses of the hydrophilic layer were measured before and after the rubbing test, and the residual ratio was calculated using the following formula: Residual ratio [%] = (thickness of hydrophilic layer after rubbing test / thickness of hydrophilic layer before rubbing test) × 100.

[0135] When the residual rate is high, specifically 40% or more, the functional film of the present invention can be judged to have high abrasion resistance.

[0136] In the above step (s), the load was 2.5 N / cm ２ It is preferable that the residual rate is 30% or more when the rubbing time is set to 250 seconds. This means that the functional film of the present invention can be judged to have high abrasion resistance even when subjected to a high-load rubbing test under stricter conditions.

[0137] The thickness of the functional film can be measured using the methods described above.

[0138] (3) Total Light Transmittance From the viewpoint of optical properties, the total light transmittance of the functional film is preferably 70% or more, and more preferably in the range of 80 to 99%. The higher the total light transmittance, the higher the transparency, which is preferable from the viewpoint of application to optical components. The total light transmittance of the functional film can be measured, for example, using a haze meter "NDH5000SP" (manufactured by Nippon Denshoku Industries Co., Ltd.). If measurement is difficult due to the curvature or size of the lens, it can also be substituted by attaching the same functional film to flat glass made of the same material and measuring the total light transmittance of this test piece. The total light transmittance can be adjusted by the type of material of each layer.

[0139] (4) Contact angle of functional film The functional film of the present invention is designed to wet and spread out all at once when multiple rain or mist-like water droplets are attached, and the contact angle of a single water droplet does not necessarily represent the performance of the hydrophilic function. In practice, the MTF value represents the performance, but since there is a general tendency that the smaller the contact angle, the better, it is described as a reference index. From the viewpoint of visibility, the functional film of the present invention preferably has a surface contact angle A1 of 30° or less, more preferably 10° or less, after being stored for 100 hours in an 85°C, 85% RH (high temperature, high humidity) environment.

[0140] The functional film of the present invention preferably has hydrophilicity or antifogging properties. In the present invention, "hydrophilic" means that the contact angle A1 is greater than 10° and not more than 30°. "Antifogging" means that the contact angle A1 is not more than 10°.

[0141] The contact angle A1 can be measured by the following procedure. The functional film is left in an environment of 85°C and 85% RH for 100 hours. Then, 10 μL of pure water is dropped onto the surface of the functional film in an environment of 23°C and 50% RH. The static contact angle 5 seconds after the drop is measured using, for example, a contact angle measuring device "G-1" (manufactured by Elma), and this is defined as the contact angle A1.

[0142] The functional film of the present invention preferably has a surface contact angle A2 of 30° or less, more preferably 10° or less, after storage for 100 hours in a dry environment at 85° C. (high temperature). The contact angle A2 can be measured using the same procedure as in measuring the contact angle A1, except that the temperature is changed to 85° C. and the environment is dry.

[0143] 7. Method for Producing Functional Film The method for producing a functional film of the present invention is the method for producing the functional film described above, characterized by comprising the steps of forming a layer containing the ion-binding compound by a dry film-forming method, and heating the formed layer containing the ion-binding compound at a temperature higher than that during film formation.

[0144] Specifically, an ion-bonding compound is dry-formed onto a substrate. This forms a layer that will become a precursor to the hydrophilic layer. In this precursor layer, the metal element does not yet have multiple pores. Then, by exposing the hydrophilic layer to a moisture-containing environment in an aging process, multiple pores are formed in the hydrophilic layer.

[0145] After all the film formation is completed, the hydrophilic layer is heated at a temperature higher than that during film formation. This is thought to cause the ion-binding compounds to become denser, reducing the size of the multiple pores formed during the aging process. It is thought that the hardness and abrasion resistance are improved in areas where the ion-binding compounds are denser. Meanwhile, since the hydrophilic layer has multiple pores, it has a large surface area that interacts with water molecules, which is thought to improve hydrophilicity or anti-fogging properties.

[0146] In the process of forming the functional film, it is preferable to form all layers by dry film formation, which can improve the adhesion of the functional film to the substrate and the abrasion resistance, and can easily form a fine uneven structure and a porous structure.

[0147] <Step (I) of forming the uneven-shape forming layer> In the present invention, the "uneven-shape forming layer" refers to a layer that serves as a precursor before the formation of the convex-shaped portion or the uneven-shape layer. Specifically, it refers to a layer in a state before the material for the convex-shaped portion or the uneven-shape layer is dry-formed and exposed to a moisture-containing environment. Therefore, the uneven-shape forming layer is not yet granular.

[0148] Step (I) is a step of forming the unevenness-forming layer on a substrate. A reflectance-adjusting layer and a photocatalyst layer may be provided on the substrate, and the unevenness-forming layer may be formed on the photocatalyst layer. Alternatively, the unevenness-forming layer may be formed directly on the substrate without providing a reflectance-adjusting layer and a photocatalyst layer. When the unevenness-forming layer is formed directly on the substrate, the functional film functions as an anti-reflection film.

[0149] <Step (II) of forming convex portions or uneven layer> Step (II) is a step of forming particulate convex portions or uneven layer by exposing the uneven layer formed in step (I) to a moisture-containing environment. For example, exposing to a moisture-containing environment may be performed by moving from the inside to the outside of a dry film-forming apparatus. The time for exposing to the moisture-containing environment (aging time) is preferably within a range of 0.5 to 300 hours.

[0150] Steps (I) and (II) will be described in detail. In the following description, the functional membrane will be described as being composed of only a hydrophilic layer, but the functional membrane may have other layers. In the following description, the hydrophilic layer will be described as being composed of a textured layer 5 and a coating layer 6, but the hydrophilic layer does not necessarily have to have the coating layer 6.

[0151] 14 and 15 are explanatory views showing an example of a method for manufacturing a functional film (hydrophilic layer).

[0152] A film of an ion-bonding compound is formed on the substrate 2 by a dry film formation method. This forms a textured layer, which serves as a precursor before the textured layer is formed. As the dry film formation method, a resistance heating vacuum deposition method or the like is preferably used, as described above.

[0153] The textured layer on the substrate 2 is then exposed to a moist environment. This aging process causes the ion-bonding compound to absorb water and become particulate. The particles of the ion-bonding compound can be easily and uniformly distributed within the layer, forming a textured layer 5 on the substrate 2. By forming the textured layer 5, the surface of the layer becomes granular, allowing for the formation of a finer textured structure.

[0154] 15, after the aging step, a coating layer 6 may be formed on the textured layer 5 by dry deposition. As a dry deposition method, the IAD method or the like is preferably used, as described above, and a coating layer material appropriate for the type of functional film is deposited. By forming the coating layer 6 on the textured layer 5 in this manner, the functional film 1 of the present invention can be obtained, which has a porous surface with pores 6c and a finely textured structure.

[0155] Although not shown in Figure 15, it is preferable that the ionic compound is also dispersed and contained in the coating layer. Therefore, it is preferable that the coating layer be formed by alternately laminating layers of the ionic compound and layers composed of other coating layer materials. This allows the ionic compound to be dispersed in the coating layer. Furthermore, by reducing the thickness of each layer and increasing the number of layers, the dispersibility of the ionic compound can be improved. Note that the dispersibility of the ionic compound can be adjusted by adjusting the thickness and number of each layer.

[0156] The ion-binding compound layer does not necessarily need to be formed or arranged in the form of relatively large particles because it does not need to form a rough structure. In other words, the ion-binding compound layer does not need to be exposed to a moist environment during its formation process. Therefore, it is preferable that the coating layer composed of the ion-binding compound layer and a layer composed of other coating layer materials be formed in a vacuum environment from start to finish. By making the coating layer have a structure with relatively few roughness, a hydrophilic layer with an appropriate porous structure can be formed.

[0157] <Step (III) of storing under high temperature and high humidity> Step (III) of storing under high temperature and high humidity is a step of reducing anionic components by storing the functional film formed as described above under high temperature and high humidity. The high temperature and high humidity preferably means, for example, storing the film under a temperature range of 50 to 110°C and an RH of 50 to 95% for 0.5 to 300 hours. The purpose of this step is to move ionic atoms, and a humidity of 50% or more is desirable.

[0158] The step (III) reduces the amount of anionic components in the functional film, thereby improving hydrophilicity. Examples of anionic components include Cl ions (chloride ions) and F ions (fluoride ions). The amount of anionic components can be confirmed by analyzing the composition of the functional film using an X-ray photoelectron spectroscopy (XPS).

[0159] <Step (IV) of exposing to an environment containing an etching gas> Step (IV) of exposing to an environment containing an etching gas is a step of exposing the functional film to an environment containing an etching gas, thereby adjusting the size of gaps through which active chemical species generated by the photocatalytic reaction can pass.

[0160] An example of an etching gas is HF gas. It is preferable to place the functional film in an environment containing such an etching gas for 1 to 60 minutes. Typically, etching involves converting an etching gas into plasma and applying it to the sample surface, resulting in a chemical and physical attack that scrapes the sample surface. However, in this case, the colliding molecules also act as abrasives, making the surface smooth and, conversely, blocking atomic-level pores. On the other hand, in the above-mentioned step (IV), exposure to an environment containing an etching gas allows the corrosive gas that has entered the pores to expand the pores while preventing gaps from being blocked. This allows for a more porous structure, and, for example, when the functional film has a photocatalytic layer, the photocatalytic passage efficiency can be increased.

[0161] 3, the functional film 1 may further include a concave-convex layer 5 and a cover layer 6 formed on the cover layer 6. In this case, the above steps (I) to (IV) are repeated to form the layers.

[0162] <Step (V) of Heating the Functional Membrane> Step (V) of heating the functional membrane is a step of heating the functional membrane after completing the formation of all of the functional membranes (hydrophilic layers) by repeating the above steps (I) to (IV). This step is performed in a dry environment, since the purpose is to reduce the pore size. The dry environment can be achieved, for example, using a small high-temperature chamber "ST-120" (manufactured by Espec Corporation). Note that the small chamber does not have a humidifier installed, so the dry environment can be achieved.

[0163] The heating temperature is preferably within a range of 50 to 360° C., more preferably within a range of 70 to 160° C., and even more preferably within a range of 90 to 130° C. The heating time is preferably within a range of 10 minutes to 48 hours, and more preferably within a range of 1 to 12 hours.

[0164] The mechanism by which the abrasion resistance can be improved and the hydrophilicity can be maintained by carrying out the step (V) of heating the functional film is not clear, but is speculated as follows.

[0165] 16 is a graph showing the spectral reflectance in the wavelength range of 400 to 780 nm of each functional film before and after performing step (V). The horizontal axis represents wavelength [nm], and the vertical axis represents reflectance [%]. The graph shows that the reflection characteristics change before and after performing step (V), i.e., before and after heating. Specifically, in the wavelength range of 400 to 520 nm, the functional film before heating has a higher reflectance, whereas in the wavelength range of 520 to 780 nm, the functional film after heating has a higher reflectance.

[0166] This suggests that the structure inside the functional film changes before and after heating, causing the apparent refractive index to increase. The increase in apparent refractive index means that the density inside the functional film has increased, which means that the size of the pores has become smaller.

[0167] 8. Substrate The substrate is not particularly limited, and is preferably, for example, an inorganic material, an organic material, or a combination thereof. In particular, when visible light is used, the substrate is preferably glass or resin from the viewpoint of transparency. When infrared light is used, the substrate is preferably silicon (Si), chalcogenide, silicon carbide (SIC), or sapphire from the viewpoint of transparency.

[0168] Examples of inorganic materials include TaFD-based glass, fused silica glass, synthetic silica glass, glass lenses, silicon, chalcogenide, chromium, etc. Examples of inorganic materials include optical glasses "H-ZLAF55D" and "H-ZLAF55F" (manufactured by CDGM).

[0169] Examples of organic materials include polyethylene terephthalate (PET), acrylic resin, vinyl chloride resin, cycloolefin polymer (COP), cycloolefin copolymer (COC), etc. Examples of organic materials include polymethyl methacrylate (PMMA), polycarbonate (PC), polypropylene (PP), polyethylene (PE), etc.

[0170] The organic material may be an ultraviolet-curable resin, which may be either a radical polymerization type or a cationic polymerization type. Examples of radical polymerization type ultraviolet-curable resins include acrylate resins, urethane acrylates, polyester acrylates, polybutadiene acrylates, epoxy acrylates, silicon acrylates, polyacrylamides, and ene-thiol resins. Examples of cationic polymerization type ultraviolet-curable resins include vinyl ether resins, alicyclic epoxy resins, glycidyl ether epoxy resins, polyurethane vinyl ethers, and polyester vinyl ethers.

[0171] The organic material may be a thermosetting resin, such as an epoxy resin, a phenolic resin, an unsaturated polyester resin, a urea resin, a melamine resin, a silicone resin, or a polyurethane. The substrate may also be an inorganic material, such as glass, on which a film made of an organic material is formed.

[0172] When the functional film is applied to an optical device, the substrate is preferably glass from the viewpoint of transparency. When the functional film is applied to an inkjet head, the substrate is preferably silicon. Furthermore, when the functional film is applied to a mold, the substrate is preferably SiC (silicon carbide), cemented carbide, or the like.

[0173] 9. Other Films Other films may be disposed between the functional film of the present invention and the substrate. Examples of other films include a photocatalytic layer and a reflectance adjusting layer.

[0174] (1) Photocatalytic layer The photocatalytic layer is made of TiO as a metal oxide having photocatalytic function. ２ Preferably, the composition contains TiO ２ It is more preferable that the photocatalytic layer contains TiO as a main component. ２ By containing as a main component, the refractive index can be increased and the light reflectance of the functional film can be reduced.

[0175] In the present invention, the term "main component" refers to a component that accounts for 80 mass % or more of all components that constitute the photocatalyst layer. ２ The proportion of is preferably in the range of 90 to 99.9 mass %, more preferably in the range of 97 to 99.9 mass %.

[0176] In the present invention, the term "photocatalytic function" refers to the function of decomposing organic substances by photocatalysis. ２ When ultraviolet light is irradiated onto the surface of the substrate, electrons are released, and then active chemical species, active oxygen or hydroxyl radicals (OH radicals), are generated. The strong oxidizing power of the active oxygen or hydroxyl radicals decomposes organic matter. ２ By using a photocatalyst layer containing the compound (I), it is possible to prevent contamination of the optical member with organic matter or the like adhering thereto.

[0177] The photocatalytic layer is preferably formed by a dry film formation method. Examples of dry film formation methods include vapor deposition and sputtering. Examples of vapor deposition methods include vacuum vapor deposition, ion beam vapor deposition, ion plating, and ion-assisted vapor deposition (IAD). Examples of sputtering methods include sputtering, ion beam sputtering, and magnetron sputtering. Among these, the film formation method is preferably vacuum vapor deposition, IAD, or sputtering, and particularly preferably IAD.

[0178] (2) Reflectance Adjusting Layer The reflectance adjusting layer preferably comprises at least one low refractive index layer and at least one high refractive index layer.

[0179] An example of the configuration of the reflectance adjusting layer is a configuration in which, from the top of the substrate, a first low refractive index layer, a high refractive index layer, and a second low refractive index layer are arranged in that order. Examples of the materials and thicknesses of each layer are shown below, but the present invention is not limited to these.

[0180] 1) First low refractive index layer: Constituent material = SiO ２ 2) High refractive index layer: Constituent material = Ta ２ O ５ -TiO ２ "OA600" (Canon Optron Inc.), layer thickness = 21 nm 3) Second low refractive index layer: constituent material = SiO ２ , layer thickness = 33 nm Note that the above configuration example is just an example. The reflectance adjustment layer may have a configuration in which the order of the low refractive index layers and the high refractive index layers is changed from that of the above configuration example, or may have a configuration in which a larger number of low refractive index layers and a larger number of high refractive index layers are stacked.

[0181] (2.1) Low Refractive Index Layer The low refractive index layers (first and second low refractive index layers) are preferably made of a material having a refractive index of less than 1.7. ２ It is preferable that the main component is Al, and it is more preferable that the other metal oxides are further contained. ２ O ３ (aluminum oxide), MgF ２ (magnesium fluoride), etc.

[0182] (2.2) High Refractive Index Layer The high refractive index layer is preferably made of a material having a refractive index of 1.7 or more, and more preferably made of a material having a refractive index of 1.9 or more. Examples of materials having a refractive index of 1.7 or more include a mixture of Ta oxide and Ti oxide, Ti oxide, Ta oxide, and a mixture of La oxide and Ti oxide. Among these, materials having a refractive index of 1.7 or more include Ta ２ O ５ or TiO ２ Preferably, Ta ２ O ５ It is more preferable that:

[0183] (2.3) Thickness The thickness of the reflectance adjusting layer is not particularly limited, but is preferably 500 nm or less from the viewpoint of anti-reflection performance. The thickness of the reflectance adjusting layer is more preferably in the range of 50 to 500 nm. A thickness of 50 nm or more allows the anti-reflection function to be exerted. A thickness of 500 nm or less reduces error sensitivity and improves the yield rate in terms of the spectral characteristics of the lens.

[0184] In the above configuration example, the thickness of the first low refractive index layer is preferably within a range of 5 to 150 nm, the thickness of the second low refractive index layer is preferably within a range of 5 to 100 nm, and the thickness of the high refractive index layer is preferably within a range of 1 to 70 nm.

[0185] (2.4) Film Formation Method The film formation method for the reflectance adjusting layer is preferably a dry film formation method. Examples of dry film formation methods include vapor deposition and sputtering. Examples of vapor deposition methods include vacuum deposition, ion beam deposition, ion plating, and ion-assisted deposition (IAD). Examples of sputtering methods include sputtering, ion beam sputtering, and magnetron sputtering. Among these, the film formation method is preferably vacuum deposition, IAD, or sputtering, and particularly preferably IAD.

[0186] 10. Laminate The laminate of the present invention is characterized by having a substrate and the above-described functional film. In particular, when the substrate is glass, the substrate and the functional film have high adhesion and excellent abrasion resistance. In addition, from the viewpoint of high transparency, the laminate can be applied to optical devices.

[0187] 11. Optical Devices The functional film and laminate of the present invention can be applied to optical devices. Examples of optical devices include lenses, lens cover glass, antibacterial cover materials, antifungal coating materials, mirrors, etc. More specifically, examples include in-vehicle lenses, communication lenses, antibacterial lenses for endoscopes, components for personal computers or smartphones, and antibacterial cover materials for personal computers or smartphones. Other examples include eyeglasses, ceramics (toilet bowls, tableware, etc.), antifungal coatings (bathtubs, sinks, etc.), building materials (window glass, etc.), etc. Among these, the functional film of the present invention is preferably applied to in-vehicle lenses.

[0188] 12. Inkjet Head The functional film of the present invention can be applied to an inkjet head. In an inkjet head to which the functional film of the present invention is applied, the substrate is preferably silicon from the viewpoints of durability and processing characteristics. The inorganic substance contained as the main component in the coating layer of the functional film is preferably SiC (silicon carbide) from the viewpoint of ink wiping properties.

[0189] 13. Mold The functional film of the present invention can be applied to a mold. In a mold to which the functional film of the present invention is applied, the substrate is preferably SiC or a cemented carbide from the viewpoint of strength. The inorganic substance contained as the main component in the coating layer of the functional film is preferably SiC, a Si-containing material, from the viewpoint of hardness.

[0190] The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In the examples, the terms "parts" and "%" are used, but they represent "parts by mass" or "% by mass" unless otherwise specified. In the following examples, operations were carried out at room temperature (25°C) unless otherwise specified.

[0191] In forming each of the following layers, if the same film formation equipment is used in the preceding and succeeding steps, it is assumed that the films are formed continuously without being exposed to the atmosphere, unless otherwise specified. If different film formation equipment is used in the preceding and succeeding steps, it is assumed that the films are exposed to the atmosphere.

[0192] The configuration of the functional films produced in the laminates 1 to 2 and 5 to 15 was the same as that of the functional film shown in Fig. 3. A reflectance adjusting layer 7, a photocatalytic layer 8, an intermediate layer 4, and a hydrophilic layer 3 were formed in this order on the substrate 2. The laminates 3, 4, 16, and 17 were configured without the intermediate layer 4.

[0193] 17 to 22 are cross-sectional schematic diagrams of the functional membrane of the present invention at each manufacturing step. FIG. 17 is a cross-sectional schematic diagram after the step (2) of forming a photocatalytic layer described below. FIG. 18 is a cross-sectional schematic diagram after the step (4.1.1) of forming a textured layer described below. Note that when an intermediate layer was not provided, the textured layer 5 was formed on the photocatalytic layer. In FIG. 18, only the intermediate layer 4 and the textured layer 5 are illustrated, and other layers are omitted. FIG. 19 is a cross-sectional schematic diagram after the step (4.1.3) of forming a textured layer described below. In FIG. 19, only the textured layer 5 and the first coating layer 61 in the hydrophilic layer are illustrated, and other layers are omitted. FIG. 20 is a cross-sectional schematic diagram after the step (4.1.5) of forming a textured layer described below. In FIG. 20, only the textured layer 5 and the second coating layer 62 in the hydrophilic layer are illustrated, and other layers are omitted. Fig. 21 is a cross-sectional view schematically illustrating the structure after the step of forming the textured layer (4.1.7) described below. Fig. 21 shows only the textured layer 5 and the third coating layer 63 in the hydrophilic layer, with the other layers omitted. Fig. 22 is a cross-sectional view schematically illustrating the structure after the step of forming the fourth coating layer (4.1.8) described below. Fig. 22 shows only the fourth coating layer 64 in the hydrophilic layer, with the other layers omitted. In other words, the functional membrane shown in Fig. 3 is, in detail, a structure in which the structures shown in Figs. 17 to 22 are stacked in order.

[0194] 19 to 22, in order to emphasize that the ionic bonding compound contained in the ionic bonding compound layer 65 is in the form of extremely small particles, the particles of the ionic bonding compound are shown with wide intervals between them. However, in reality, the intervals between the particles are very narrow, and the SiO ２ For example, in FIG. ２ The 7 nm layer is a SiO layer formed on the NaCl layer. ２ This means that the thickness of the layer is 7 nm, and the SiO ２ The thickness of SiO ２ It is not included in the layer thickness.

[0195] [Preparation of Laminate 1] 1. Preparation of Substrate (1) Preparation of Substrate (Taf Glass Lens) A lens made of glass material "H-ZLAF55D" (manufactured by CDGM) processed for an in-vehicle lens was prepared as a substrate. This lens was cleaned for 600 seconds using a UV ozone device (manufactured by Technovision).

[0196] 2. Formation of Functional Film (1) Formation of Reflectance Adjusting Layer A reflectance adjusting layer was formed on each substrate by the following procedure. The reflectance adjusting layer had a first low refractive index layer, a high refractive index layer, and a second low refractive index layer, which were deposited in this order.

[0197] (Formation of first low refractive index layer) Using an IAD vacuum deposition apparatus "BIS-1300DNN" (manufactured by Shincron Co., Ltd.), a SiO ２ A first low refractive index layer (containing SiO ２ A layer (31 nm) was deposited under the following conditions.

[0198] Chamber conditions: Heating temperature: 25°C Starting vacuum: 5.0 x 10 －３ Pa <<Evaporation source of film-forming material>> Electron gun <<IAD ion source>> RF ion source NIS-175-3 manufactured by Shincron Co., Ltd. Film-forming material of first low refractive index layer: SiO ２ (Canon Optron, product name "SiO ２ ")

[0199] The substrate was placed in an IAD vacuum deposition apparatus, and SiO was used as a film-forming material in the first evaporation source. ２The first low refractive index layer (SiO ２ A layer) was formed.

[0200] The IAD conditions were an acceleration voltage of 1000 V, an acceleration current of 1000 mA, a suppressor voltage of 500 V, and a neutralization current of 1500 mA. The IAD introduced gas was O ２ The conditions were: 50 sccm of nitrogen gas, 0 sccm of Ar gas, and 10 sccm of neutral gas Ar.

[0201] (Formation of high refractive index layer) Using an IAD vacuum deposition apparatus "BIS-1300DNN" (manufactured by Shincron Co., Ltd.), a high refractive index layer (Ta ２ O ５ -TiO ２ , 21 nm) was deposited under the following conditions.

[0202] Chamber conditions: Heating temperature: 25°C Starting vacuum: 5.0 x 10 －３ Pa <<Evaporation source of film-forming material>> Electron gun <<IAD ion source>> RF ion source NIS-175-3 manufactured by Shincron Co., Ltd. Film-forming material for high refractive index layer: Ta ２ O ５ -TiO ２ (Canon Optron, product name "OA-600")

[0203] The above-mentioned film-forming material was loaded into the second evaporation source of the IAD vacuum evaporation device. The film-forming material was evaporated at a film-forming rate of 4 Å / sec to form a high-refractive index layer (Ta) having a thickness of 21 nm on the first low-refractive index layer. ２ O ５ -TiO ２ , 21 nm).

[0204] The IAD conditions were an acceleration voltage of 1000 V, an acceleration current of 1000 mA, a suppressor voltage of 500 V, and a neutralization current of 1500 mA. The IAD introduced gas was O ２ The gas pressure was controlled to 2×10 －２ To make it so that it becomes Pa, the automatic pressure controller ２Gas was introduced. Note that hereinafter, the auto pressure controller is also referred to as "APC."

[0205] (Formation of Second Low Refractive Index Layer) The IAD vacuum deposition apparatus "BIS-1300DNN" (manufactured by Shincron Co., Ltd.) was used as is to form a second low refractive index layer (SiO ２ A layer (33 nm thick) was deposited under the following conditions.

[0206] Chamber conditions: Heating temperature: 25°C Starting vacuum: 5.0 x 10 －３ Pa <<Evaporation source of film-forming material>> Electron gun <<IAD ion source>> RF ion source NIS-175-3 manufactured by Shincron Co., Ltd. Film-forming material for second low refractive index layer: SiO ２ (Canon Optron, product name "SiO ２ ")

[0207] The first evaporation source of the IAD vacuum evaporation device was filled with SiO as a film forming material. ２ The second low refractive index layer (SiO 2 ) was deposited at a deposition rate of 3 Å / sec to a thickness of 33 nm on the high refractive index layer. ２ A layer) was formed.

[0208] The IAD conditions were an acceleration voltage of 1000 V, an acceleration current of 1000 mA, a suppressor voltage of 500 V, and a neutralization current of 1500 mA. The IAD introduced gas was O ２ The conditions were: 50 sccm of nitrogen gas, 0 sccm of Ar gas, and 10 sccm of neutral gas Ar.

[0209] (2) Formation of Photocatalytic Layer Using an IAD vacuum deposition apparatus "BIS-1300DNN" (manufactured by Shincron Co., Ltd.), a photocatalytic layer (TiO ２ The layer (102 nm thick) was deposited under the following conditions:

[0210] Chamber conditions: Heating temperature: 25°C Starting vacuum: 5.0 x 10 －３ Pa <<Vapor source of film-forming material>> Electron gun <<IAD ion source>> RF ion source NIS-175-3 manufactured by Shincron Co., Ltd. Film-forming material for photocatalytic layer: TiO ２ (Manufactured by Fuji Titanium Industry Co., Ltd., product name "T.O.P (Ti３ O ５ The film-forming material was loaded into the third evaporation source of the IAD vacuum evaporation device. The material was evaporated at a film-forming rate of 2 Å / sec to form a photocatalytic layer (TiO ２ A layer) was formed.

[0211] The IAD conditions were an acceleration voltage of 300 V, an acceleration current of 300 mA, a suppressor voltage of 1000 V, and a neutralization current of 600 mA. The IAD introduced gas was O ２ The gas pressure was controlled to 3×10 －２ From APC to O ２ Gas was introduced.

[0212] (3) Formation of Intermediate Layer (3.1) Formation of Intermediate Layer An intermediate layer was formed on the photocatalytic layer by the following procedure. ２ O ３ An intermediate layer (5 nm) containing the compound was formed under the following conditions.

[0213] Chamber conditions: Heating temperature: 25°C Starting vacuum: 5.0 x 10 －３ Pa

[0214] <<Evaporation source of film-forming material>> Electron gun

[0215] <IAD ion source> RF ion source NIS-175-3 manufactured by Shincron Co., Ltd. Intermediate layer deposition material: Al ２ O ３ Each substrate was placed in an IAD vacuum deposition apparatus, and Al was used as a film-forming material in the first evaporation source. ２ O ３ The intermediate layer (Al) was deposited at a deposition rate of 3 Å / sec to a thickness of 5 nm. ２ O ３ The IAD conditions were an acceleration voltage of 1000 V, an acceleration current of 1000 mA, a suppressor voltage of 500 V, and a neutralization current of 1500 mA. The IAD gas introduced was O ２ The conditions were: 50 sccm of nitrogen gas, 0 sccm of Ar gas, and 10 sccm of neutral gas Ar.

[0216] In Table I below, "with unevenness" indicates that unevenness processing (etching) was performed on the intermediate layer, and "without unevenness" indicates that unevenness processing was not performed.

[0217] <Etching of Intermediate Layer> An Ag mask was formed on the intermediate layer. The Ag mask was formed using a film forming apparatus (BMC-800T, manufactured by Shincron Co., Ltd.) under the following conditions. The Ag mask had a thickness of 20 nm.

[0218] <<Conditions inside the chamber>> Heating temperature: 180°C Starting vacuum: 5.0 x 10 －３ Pa Film formation rate: 3 Å / sec After forming the Ag mask, a CE-300I (manufactured by ULVAC) was used as an etching device, and film formation was performed under the following conditions. The depth and average diameter of the recesses in the intermediate layer were adjusted by changing the etching time. <Etching conditions> Antenna RF: 400 W Bias RF: 38 W APC pressure: 0.5 Pa CHF3 flow rate: 20 sccm Total etching time: 30 seconds <Removal of Ag mask> After forming the recesses, the sample was immersed in Pure Etch Au100 (manufactured by Hayashi Pure Chemical Industries, Ltd.) for 5 seconds to remove the Ag mask. The sample was then ultrasonically cleaned in pure water and cleaned for 600 seconds with a UV ozone device (Technovision).

[0219] (4) Formation of Hydrophilic Layer (4.1) Formation of Hydrophilic Layer A hydrophilic layer was formed on each photocatalytic layer or each intermediate layer by the following procedure. Using an IAD vacuum deposition apparatus "BIS-1300DNN" (manufactured by Shincron Co., Ltd.), a hydrophilic layer (90 nm) containing NaCl and NaF as ion-binding compounds was formed on the substrate under the following conditions. As shown in Figure 3, the hydrophilic layer had a configuration including, from the closest to the intermediate layer, a textured layer 5 (5 nm), a first coating layer 61 (28 nm), a textured layer 5 (4 nm), a second coating layer 62 (16 nm), a textured layer 5 (3 nm), a third coating layer 63 (16 nm), a textured layer 5 (2 nm), and a fourth coating layer (16 nm).

[0220] (4.1.1) Formation of Textured Layer The textured layer 5 (NaCl layer, 5 nm) shown in FIG. 18 was formed by the following procedure. (NaCl Layer) The substrate was removed from the IAD vacuum deposition device and placed in the following film-forming device to form a textured layer (NaCl layer, 5 nm) made of NaCl. A film-forming device "BMC-800T" (manufactured by Shincron Co., Ltd.) was used for film formation, and NaCl was subjected to resistance heating vapor deposition under the following conditions. Next, the substrate was returned to the atmosphere once to form particles, thereby obtaining a textured layer (NaCl layer, 5 nm). Heating temperature: 25°C Starting vacuum: 5.0 x 10 －３ Pa Film formation rate: 1 Å / sec

[0221] (4.1.2) Formation of First Coating Layer An ion-bonding compound layer 65 (NaCl layer, 1 nm) and SiO 2 were formed on the textured layer (NaCl layer, 5 nm) by the following procedure. ２ The first coating layer 61 was formed from a layer (1 nm or 5 nm).

[0222] (NaCl layer) An IAD vacuum deposition apparatus "BIS-1300DNN" (manufactured by Shincron Co., Ltd.) was used for film formation under the following conditions, and an ion-bonding compound layer (NaCl layer, 1 nm) was further formed on the uneven layer (NaCl layer, 5 nm). <Conditions in chamber> Heating temperature: 25°C Starting vacuum: 5.0 × 10 －３ Pa 《Deposition material evaporation source》 Electron gun 《IAD ion source》 None

[0223] (SiO ２ The substrate was placed in the IAD vacuum deposition apparatus described below, and two SiO layers were deposited on the ion-bonding compound layer (NaCl layer, 1 nm). ２ layer (SiO ２ layer 1 nm, and SiO ２ After the ion-bonding compound layer was formed, two SiO layers were successively formed while the vacuum environment was maintained. ２ A layer was deposited.

[0224] Chamber conditions: Heating temperature: 25°C Starting vacuum: 5.0 x 10 －３Pa <<Vapor source of film-forming material>> Electron gun <<IAD ion source>> RF ion source NIS-175-3 manufactured by Shincron Co., Ltd. Film-forming material of first coating layer: SiO ２ (Canon Optron, product name "SiO ２ ")

[0225] The first evaporation source of the IAD vacuum evaporation device was filled with SiO as a film forming material. ２ The SiO layer was deposited at a deposition rate of 3 Å / sec to a thickness of 1 nm on the ion-bonding compound layer (NaCl layer, 1 nm). ２ The IAD conditions were an acceleration voltage of 1000 V, an acceleration current of 1000 mA, a suppressor voltage of 500 V, and a neutralization current of 1500 mA. The IAD gas introduced was O ２ The conditions were: 50 sccm of nitrogen gas, 0 sccm of Ar gas, and 10 sccm of neutral gas Ar.

[0226] Next, SiO was measured under the same conditions except that the IAD was turned off. ２ A layer (5 nm) was deposited, followed by a NaCl layer (1 nm) / SiO ２ Layer (1 nm) / SiO ２ This unit was further repeated three times to form a first coating layer consisting of four of the above units.

[0227] (4.1.3) Formation of the textured layer SiO of the first coating layer ２ A textured layer (NaF layer, 4 nm) was formed on the layer (5 nm) by the following procedure.

[0228] (NaF layer) The substrate was removed from the IAD vacuum deposition apparatus and placed in the following film formation apparatus. ２ A roughened layer (NaF layer, 4 nm) made of NaF was formed on the layer (5 nm). A film-forming device "BMC-800T" (manufactured by Shincron Co., Ltd.) was used for film formation, and NaF was subjected to resistance heating vapor deposition under the following conditions. The NaF was then returned to the atmosphere once to be granulated, yielding a roughened layer (NaF layer, 4 nm). Heating temperature: 25°C, Starting vacuum: 5.0 x 10 －３ Pa Film formation rate: 1 Å / sec

[0229] (4.1.4) Formation of Second Coating Layer A SiO 2 layer containing an ion-bonding compound layer 65 (NaCl layer, 1 nm) shown in FIG. 20 was formed on the textured layer (NaF layer, 4 nm) by the following procedure. ２ A second coating layer 62 consisting of a layer (7 nm) was formed.

[0230] (NaCl Layer) An IAD vacuum deposition apparatus "BIS-1300DNN" (manufactured by Shincron Co., Ltd.) was used to form the film under the following conditions: An ion-bonding compound layer (NaCl layer, 1 nm) was further formed on the uneven layer (NaF layer, 4 nm).

[0231] Chamber conditions: Heating temperature: 25°C Starting vacuum: 5.0 x 10 －３ Pa 《Deposition material evaporation source》 Electron gun 《IAD ion source》 None

[0232] (SiO ２ The substrate was placed in the IAD vacuum deposition apparatus described below, and one SiO layer was deposited on the formed ion-bonding compound layer (NaCl layer, 1 nm). ２ The film was formed using an IAD vacuum deposition device "BIS-1300DNN" (manufactured by Shincron Co., Ltd.) under the following conditions, and a SiO layer (7 nm thick) was formed on the ion-bonding compound layer (NaCl layer, 1 nm). ２ A layer (7 nm) was formed.

[0233] Chamber conditions: Heating temperature: 25°C Starting vacuum: 5.0 x 10 －３ Pa <<Evaporation source of film-forming material>> Electron gun <<IAD ion source>> RF ion source NIS-175-3 manufactured by Shincron Co., Ltd. Film-forming material for second coating layer: SiO ２ (Canon Optron, product name "SiO ２ ") SiO as a film forming material was placed in the first evaporation source of the IAD vacuum evaporation device. ２ The SiO layer was deposited at a deposition rate of 3 Å / sec to a thickness of 7 nm on the ion-bonding compound layer (NaCl layer, 1 nm). ２ A layer was formed.

[0234] The IAD conditions were an acceleration voltage of 1000 V, an acceleration current of 1000 mA, a suppressor voltage of 500 V, and a neutralization current of 1500 mA. The IAD introduced gas was O ２ The conditions were: 50 sccm of nitrogen gas, 0 sccm of Ar gas, and 10 sccm of neutral gas Ar.

[0235] In this way, NaCl layer (1 nm) / SiO ２ This unit was further repeated once to form a second coating layer consisting of two of the above units.

[0236] (4.1.5) Formation of textured layer SiO of second coating layer ２ A textured layer (NaF layer, 3 nm) was formed on the layer (7 nm) by the following procedure.

[0237] (NaF layer) The substrate was removed from the IAD vacuum deposition apparatus and placed in the following film formation apparatus. ２ A NaF-based roughened layer (NaF layer, 3 nm) was formed on the NaF layer (7 nm). A film-forming device "BMC-800T" (manufactured by Shincron Co., Ltd.) was used for film formation, and NaF was subjected to resistance heating vapor deposition under the following conditions. The NaF was then returned to the atmosphere once to form particles, yielding a roughened layer (NaF layer, 3 nm). Heating temperature: 25°C; Starting vacuum: 5.0 x 10 －３ Pa Film formation rate: 1 Å / sec

[0238] (4.1.6) Formation of third coating layer A SiO 2 layer containing an ion-bonding compound layer 65 (NaCl layer, 1 nm) shown in FIG. 21 was formed on the textured layer (NaF layer, 3 nm) by the following procedure. ２ A third coating layer 63 consisting of a layer (7 nm) was formed.

[0239] (NaCl Layer) An IAD vacuum deposition apparatus "BIS-1300DNN" (manufactured by Shincron Co., Ltd.) was used to form the film under the following conditions: An ion-bonding compound layer (NaCl layer, 1 nm) was further formed on the uneven layer (NaF layer, 3 nm).

[0240] Chamber conditions: Heating temperature: 25°C Starting vacuum: 5.0 x 10 －３Pa 《Deposition material evaporation source》 Electron gun 《IAD ion source》 None

[0241] (SiO ２ The substrate was placed in the IAD vacuum deposition apparatus described below, and one SiO layer was deposited on the formed ion-bonding compound layer (NaCl layer, 1 nm). ２ layer (SiO ２ The film was formed using an IAD vacuum deposition device "BIS-1300DNN" (manufactured by Shincron Co., Ltd.) under the following conditions, and a SiO ２ A layer (7 nm) was formed.

[0242] Chamber conditions: Heating temperature: 25°C Starting vacuum: 5.0 x 10 －３ Pa <<Vapor source of film-forming material>> Electron gun <<IAD ion source>> RF ion source NIS-175-3 manufactured by Shincron Co., Ltd. Film-forming material of the third coating layer: SiO ２ (Canon Optron, product name "SiO ２ ") SiO as a film forming material was placed in the first evaporation source of the IAD vacuum evaporation device. ２ The SiO layer was deposited at a deposition rate of 3 Å / sec to a thickness of 7 nm on the ion-bonding compound layer (NaCl layer, 1 nm). ２ A layer was formed.

[0243] The IAD conditions were an acceleration voltage of 1000 V, an acceleration current of 1000 mA, a suppressor voltage of 500 V, and a neutralization current of 1500 mA. The IAD introduced gas was O ２ The conditions were: 50 sccm of nitrogen gas, 0 sccm of Ar gas, and 10 sccm of neutral gas Ar.

[0244] In this way, NaCl layer (1 nm) / SiO ２ This unit was further repeated once to form a third coating layer consisting of two units.

[0245] (4.1.7) Formation of textured layer SiO of third coating layer ２ A textured layer (NaF layer, 2 nm) was formed on the layer (7 nm) by the following procedure.

[0246] (NaF layer) The substrate was removed from the IAD vacuum deposition apparatus and placed in the following film formation apparatus. ２ A roughened layer (NaF layer, 2 nm) made of NaF was formed on the layer (7 nm). A film-forming device "BMC-800T" (manufactured by Shincron Co., Ltd.) was used for film formation, and NaF was subjected to resistance heating vapor deposition under the following conditions. The NaF was then returned to the atmosphere once to be granulated, yielding a roughened layer (NaF layer, 2 nm). Heating temperature: 25°C, Starting vacuum: 5.0 x 10 －３ Pa Film formation rate: 1 Å / sec

[0247] (4.1.8) Formation of Fourth Coating Layer A SiO 2 coating layer containing an ion-bonding compound layer 65 (NaCl layer, 1 nm) shown in FIG. 22 was formed on the textured layer (NaF layer, 2 nm) by the following procedure. ２ A fourth coating layer 64 consisting of a layer (7 nm) was formed.

[0248] (NaCl Layer) An IAD vacuum deposition apparatus "BIS-1300DNN" (manufactured by Shincron Co., Ltd.) was used to form the film under the following conditions: An ion-bonding compound layer (NaCl layer, 1 nm) was further formed on the uneven layer (NaF layer, 2 nm).

[0249] Chamber conditions: Heating temperature: 25°C Starting vacuum: 5.0 x 10 －３ Pa 《Deposition material evaporation source》 Electron gun 《IAD ion source》 None

[0250] (SiO ２ The substrate was placed in the IAD vacuum deposition apparatus described below, and one SiO layer was deposited on the formed ion-bonding compound layer (NaCl layer, 1 nm). ２ layer (SiO ２ The film was formed using an IAD vacuum deposition device "BIS-1300DNN" (manufactured by Shincron Co., Ltd.) under the following conditions, and a SiO ２ A layer (7 nm) was formed.

[0251] Chamber conditions: Heating temperature: 25°C Starting vacuum: 5.0 x 10 －３Pa <<Vapor source of film-forming material>> Electron gun <<IAD ion source>> RF ion source NIS-175-3 manufactured by Shincron Co., Ltd. Film-forming material of the fourth coating layer: SiO ２ (Canon Optron, product name "SiO ２ ") SiO as a film forming material was placed in the first evaporation source of the IAD vacuum evaporation device. ２ The SiO layer was deposited at a deposition rate of 3 Å / sec to a thickness of 7 nm on the ion-bonding compound layer (NaCl layer, 1 nm). ２ A layer was formed.

[0252] The IAD conditions were an acceleration voltage of 1000 V, an acceleration current of 1000 mA, a suppressor voltage of 500 V, and a neutralization current of 1500 mA. The IAD introduced gas was O ２ The conditions were: 50 sccm of nitrogen gas, 0 sccm of Ar gas, and 10 sccm of neutral gas Ar.

[0253] In this way, NaCl layer (1 nm) / SiO ２ This unit was further repeated once to form a fourth coating layer consisting of two units, thereby forming a hydrophilic layer.

[0254] (4.1.7) Heating of Functional Film The laminate having the functional film provided on the substrate was heated at 120°C for 12 hours using a small high-temperature chamber "ST-120" (manufactured by Espec Corporation) to obtain Laminate 1.

[0255] [Preparation of Laminates 2 to 17] Laminates 2 to 17 were prepared in the same manner as for the preparation of laminate 1, except that the substrate, intermediate layer, or hydrophilic layer was changed as shown in Table I.

[0256] For the laminate 16, a hydrophilic layer was formed by the sol-gel method. To form the hydrophilic layer, an inorganic antifouling coating agent "Excelpure BD-SO1" (manufactured by Chuo Motors) was dropped onto the substrate (Taf glass lens) and spin-coated at room temperature at a rotation speed of 3000 rpm. The film thickness was 100 nm. The laminate 16 was composed only of the substrate and hydrophilic layer, and did not include a reflectance adjustment layer, photocatalytic layer, or intermediate layer.

[0257] In the laminate 17, the hydrophilic layer does not contain an ionic bonding compound, but contains SiO ２ The above-mentioned SiO ２ A single layer of SiO 2 with a thickness of 100 nm was formed in the same manner as the formation of the layer. ２ A layer was formed, which was designated as the hydrophilic layer.

[0258] Details of the substrates are as follows: Taf glass: A lens made by processing the glass material "H-ZLAF55D" (manufactured by CDGM) for use in an in-vehicle lens White plate glass: A white plate glass substrate (manufactured by Piezo Parts Co., Ltd.) PC (polycarbonate): A commercially available product Acrylic (acrylic resin): A commercially available product PET (polyethylene terephthalate): A commercially available product Si (silicon): A silicon substrate (manufactured by Furuuchi Chemical Co., Ltd.) SIC (silicon carbide): A silicon carbide substrate (manufactured by Asuzac Co., Ltd.)

[0259] In Table I, a "-" next to an intermediate layer indicates that there is no intermediate layer.

[0260] The "-" in the hydrophilic layer in Table I indicates that the above-mentioned (4.1.7) heating step of the functional film was not performed. ２ This indicates that the hydrophilic layer is composed only of an ionic compound, but the hydrophilic layer does not contain an ionic compound.

[0261] The structure of each laminate in which a functional film is provided on a substrate is shown in Table I below.

[0262] For each laminate, the average spectral reflectance in the wavelength range of 400 to 700 nm was measured before and after heating the functional film, and the change [%] was calculated. The larger the change, the greater the change in the layer structure of the functional film before and after heating.

[0263]

[0264] 3. Evaluation (Evaluation 1) Average MTF value (measured image) after Kanto Loam soil abrasion test For each laminate, the average MTF value after the Kanto Loam soil abrasion test (load: 1.0 N, time: 100 seconds) was measured using the procedure described above. Note that measurement images taken with the test lens with functional film in a water-soaked state after the Kanto Loam soil abrasion test were analyzed. An average MTF value of 70% or more was evaluated as having no practical problems.

[0265] (Evaluation 2) Average MTF value (measured image) after Kanto Loam soil abrasion test For each laminate, the average MTF value after the Kanto Loam soil abrasion test (load: 2.5 N, time: 250 seconds) was measured using the procedure described above. Note that measurement images taken with the test lens with functional film in a water-wet state after the Kanto Loam soil abrasion test were analyzed. An average MTF value of 70% or more was evaluated as having no practical problems.

[0266] (Evaluation 3) Residual rate of hydrophilic layer after Kanto loam soil rubbing test For each laminate, the residual rate of the hydrophilic layer after the Kanto loam soil rubbing test (load: 1.0 N, time: 100 seconds) was measured by the above-mentioned procedure. A residual rate of 20% or more was evaluated as having no practical problem.

[0267] (Evaluation 4) Residual rate of hydrophilic layer after Kanto loam soil abrasion test For each laminate, the residual rate of the hydrophilic layer after the Kanto loam soil abrasion test (load: 2.5 N, time: 250 seconds) was measured by the above-mentioned procedure. A residual rate of 20% or more was evaluated as having no practical problem.

[0268] (Evaluation 5) Storage test under high temperature and high humidity environment (85°C, 85% RH) Each laminate was stored for 100 hours under an environment of 85°C and 85% RH. After that, the average MTF value after the Kanto Loam soil rubbing test was measured using the procedure described above. An average MTF value of 70% or more was evaluated as being satisfactory for practical use.

[0269] (Evaluation 6) Storage test in a high-temperature, dry environment (85°C, dry) Each laminate was stored for 100 hours in a dry environment at 85°C. The "85°C, dry environment" was adjusted by setting the temperature to 85°C using a small high-temperature chamber "ST-120" (manufactured by Espec Corporation). Thereafter, the average MTF value after the Kanto Loam soil abrasion test was measured using the procedure described above. An average MTF value of 70% or more was evaluated as being satisfactory for practical use.

[0270] (Evaluation 7) Average MTF value after Kanto Loam soil abrasion test (reference image) The average MTF value after the Kanto Loam soil abrasion test for each laminate was measured using the procedure described above. Note that the reference image taken with the test lens with the functional film after the Kanto Loam soil abrasion test in a non-wet state was analyzed.

[0271] The evaluation results are shown in Table II below. The higher the MTF value, the better the abrasion resistance and hydrophilicity or anti-fogging properties can be evaluated. The higher the retention rate, the better the abrasion resistance can be evaluated.

[0272]

[0273] The functional film of the present invention has an improved average MTF value (rating 1) after the Kanto Loam soil abrasion test, which indicates that it has improved abrasion resistance and can achieve both abrasion resistance and hydrophilicity or anti-fogging properties.

[0274] Comparison of Laminates 1, 3, and 5 to 7 shows that the functional film of the present invention can achieve both abrasion resistance and hydrophilicity or anti-fogging properties by having an intermediate layer containing aluminum oxide.

[0275] A comparison of Laminates 5 and 14 shows that the intermediate layer having a recessed structure can provide both abrasion resistance and hydrophilicity or anti-fogging properties.

[0276] A comparison of Laminates 1 and 15 shows that the functional film of the present invention can achieve both abrasion resistance and hydrophilicity or anti-fogging properties by using either NaCl or NaF as the ionic bonding compound.

[0277] Comparison of Laminates 1 to 4 shows that the functional film of the present invention can achieve both abrasion resistance and hydrophilicity or anti-fogging properties by heating the layer containing the ion-binding compound at a temperature higher than that during film formation.

[0278] By using the present invention, a functional film, a method for producing a functional film, and a laminate having improved abrasion resistance can be obtained. As a result, hydrophilicity or antifogging properties can be imparted to optical devices, inkjet heads, molds, etc. for a long period of time.

[0279] REFERENCE SIGNS LIST 1 Functional film 2 Substrate 3 Hydrophilic layer 4 Intermediate layer 5 Textured layer 6 Coating layer 7 Reflectance adjusting layer 8 Photocatalytic layer 10 Laminate 11 Laminate 12 Rectangular chart 13 Tip of airbrush 14 Test lens 15 Mist water 20 Reference image or measurement image 21 Center 22 Image analysis area 23 Line a 24 Line b 25 Line c

Claims

1. A functional film provided on a substrate, containing an ion-binding compound, characterized in that the average MTF value after a Kanto loam soil abrasion test measured by the following procedures (a) to (f) is 70% or more. Measurement procedure: (a) A functional film to be measured is formed on a test lens. (b) 10 g of Kanto loam soil as specified in JIS Z 8901 is mixed with 100 mL of pure water to prepare muddy water, which is then soaked in a scrubbing brush. (c) Using the scrubbing brush, a muddy water solution of 1.0 N / cm is prepared. ２ The test lens is rubbed for 100 seconds at a speed of one reciprocation per second under a load of 100 mm. (d) The test lens obtained after the Kanto Loam soil rubbing test is wetted with mist water, and a black and white rectangular chart is photographed. (e) 24 random straight lines are extracted from the obtained measurement image, and each straight line is quantified using a 256-level grayscale. (f) For each straight line, the maximum value of the numerical value of the 256-level grayscale is defined as Max, and the minimum value as Min, and the MTF value is calculated using the following formula. The arithmetic mean value of the MTF values ​​of the 24 straight lines is defined as the average MTF value. (Formula) MTF value (%) = {(Max - Min) / (Max + Min)} x 100 2. The functional film according to claim 1, characterized in that it has an intermediate layer containing aluminum oxide.

3. The functional film according to claim 2, characterized in that the intermediate layer has a recessed structure.

4. The functional film according to claim 1, characterized in that the ion-bonding compound is either NaCl or NaF.

5. The functional film according to claim 1, characterized in that the average MTF value after the Kanto Loam soil abrasion test measured by the steps (a) to (f) is 80% or more.

6. The functional film according to claim 1, characterized in that the average MTF value after the Kanto Loam soil abrasion test measured by the steps (a) to (f) is 90% or more.

7. The functional membrane according to claim 1, characterized in that the functional membrane has a plurality of pores, and the average pore diameter is within the range of 0.1 to 50 nm.

8. The functional membrane according to claim 1, characterized in that the functional membrane has a hydrophilic layer, the hydrophilic layer further has a textured layer and a coating layer, and the textured layer contains particles of the ion-binding compound.

9. The functional film according to claim 1, characterized in that the average MTF value after a storage test under an environment of 85°C and 85% RH measured by the following steps (g) to (k) is 70% or more. Measurement steps: (g) A functional film for measurement is formed on a test lens. (h) The test lens is stored under an environment of 85°C and 85% RH for 100 hours. (i) The test lens obtained after the storage test is wetted with mist water, and then a black and white rectangular chart is photographed. (j) From the obtained measurement image, 24 arbitrary straight lines are taken out, and each straight line is quantified in 256 grayscale tones. (k) For each straight line, the maximum value of the numerical value of the 256 grayscale tones is defined as Max, and the minimum value is defined as Min, and the MTF value represented by the following formula is calculated. The arithmetic mean value of the MTF values ​​of the 24 straight lines is defined as the average MTF value. (Formula) MTF value (%) = {(Max - Min) / (Max + Min)} x 100 10. The functional film according to claim 1, characterized in that the average MTF value after a storage test at 85°C in a dry environment measured by the following steps (l) to (p) is 70% or more. Measurement steps: (l) A functional film for measurement is formed on a test lens. (m) The test lens is stored in a dry environment at 85°C for 100 hours. (n) The test lens after the storage test is wetted with mist water, and a black and white rectangular chart is photographed. (o) 24 arbitrary straight lines are taken from the obtained measurement image, and each straight line is quantified in 256 grayscale tones. (p) For each straight line, the maximum value of the numerical value of the 256 grayscale tones is defined as Max, and the minimum value is defined as Min, and the MTF value represented by the following formula is calculated. The arithmetic mean value of the MTF values ​​of the 24 straight lines is defined as the average MTF value. (Formula) MTF value (%) = {(Max - Min) / (Max + Min)} x 100 11. In the above step (c), the load is 2.5 N / cm ２ 2. The functional film according to claim 1, wherein the average MTF value after a Kanto loam soil rubbing test when the rubbing time is 250 seconds is 70% or more.

12. The functional film according to claim 1, characterized in that the functional film has a hydrophilic layer, and the ratio of the average thickness of the hydrophilic layer after the Kanto Loam soil abrasion test to the average thickness of the hydrophilic layer before the Kanto Loam soil abrasion test, measured by the following steps (q) to (t), is 40% or more. Measurement steps: (q) A functional film for measurement is formed on a test lens. (r) 10 g of Kanto Loam soil as specified in JIS Z 8901 is mixed with 100 mL of pure water to prepare muddy water, which is then soaked in a scrubbing brush. (s) A pressure of 1.0 N / cm is applied using the scrubbing brush. ２ The test lens is rubbed for 100 seconds at a speed of one reciprocation per second under a load of 1000 mm. (t) The thickness of the hydrophilic layer of the functional film is measured at any 20 points on the surface of the functional film.

13. In the above step (s), the load is 2.5 N / cm ２ The functional membrane described in claim 12, characterized in that when the rubbing time is 250 seconds, the ratio of the average thickness of the hydrophilic layer after the Kanto Loam soil rubbing test to the average thickness of the hydrophilic layer before the Kanto Loam soil rubbing test is 30% or more.

14. A method for producing a functional film, the method comprising the steps of: forming a layer containing an ion-binding compound by a dry film-forming method, the functional film being the functional film described in claim 1; forming pores in the layer containing an ion-binding compound thus formed; and heating the layer containing an ion-binding compound thus formed at a temperature higher than that during film formation.

15. The method for producing a functional film according to claim 14, characterized in that the heating step causes the size of the pores in the layer containing the ion-bonding compound to become smaller than that before the heating step.

16. A laminate having a substrate and a functional film, wherein the functional film is the functional film according to claim 1.

17. The laminate according to claim 16, wherein the substrate is glass.

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