Anti-reflection film and optical component

Abstract

The present invention can provide an antireflection film and an optical member. An antireflection film (3) provided on an optical substrate (2) of an optical member (1) is provided with: a reflectance adjustment film (4) that includes a first layer (10), a second layer (11) having a higher refractive index than the first layer (10), and a third layer (12) having a lower refractive index than the second layer (11), and that has a thickness of 20 nm or more and less than 150 nm from a surface (4a); and a photocatalytic film (5) including one or more photocatalytic active layers (14) containing titanium dioxide, the photocatalytic film (5) being provided between the reflectance adjustment film (4) and the optical substrate (2), an interface (5a) on the reflectance adjustment film side being disposed at a position of 150 nm or less from a surface (4a), and the total thickness of the photocatalytic active layers (14) being 350-1000 nm (inclusive).

Description

[0001] This application is a divisional application of the application with international application number PCT / JP2018 / 011924, entry into the Chinese national phase date of October 11, 2019, national application number 201880024723.1, and invention name “Anti-reflective film and optical component”. Technical Field

[0002] The present invention relates to an anti-reflection film and an optical component. Background Art

[0003] Dirt often accumulates on the surfaces of optical components such as lenses and covers of cameras installed outdoors, such as surveillance cameras and vehicle-mounted cameras. The surfaces of optical components that accumulate dirt are generally hydrophobic. Furthermore, if the surface of a hydrophobic optical component becomes wetted by water, water droplets remain on the surface, obstructing vision. Therefore, antireflection films that maintain the hydrophilicity of the surface through the self-cleaning action of photocatalytically active titanium dioxide are known as antireflection films for optical component surfaces.

[0004] The antireflection film described in Patent Document 1 is provided on a substrate and is composed of four layers alternately stacked, each comprising a high refractive index layer containing titanium dioxide and a low refractive index layer containing silicon dioxide, with the surface being composed of a low refractive index layer. Furthermore, the thickness of each layer in the examples is, from the substrate side, 15 nm for the first layer (high refractive index layer), 30 nm for the second layer (low refractive index layer), 120 nm for the third layer (high refractive index layer), and 90 nm for the fourth layer (low refractive index layer constituting the surface).

[0005] The antireflection film described in Patent Document 2 is an antireflection film provided on a substrate. Similar to the antireflection film described in Patent Document 1, it is composed of four layers alternately stacked, each consisting of a high refractive index layer containing titanium dioxide and a low refractive index layer containing silicon dioxide. The surface is composed of a low refractive index layer. Furthermore, the thickness of each layer in the examples is, from the substrate side, 20 nm for the first layer (high refractive index layer), 25 nm for the second layer (low refractive index layer), 240 nm for the third layer (high refractive index layer), and 90 nm for the fourth layer (low refractive index layer constituting the surface).

[0006] Previous technical literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2008-003390

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2016-224113 Summary of the Invention

[0010] Technical issues to be solved by the invention

[0011] The self-cleaning effect of titanium dioxide is achieved by decomposing dirt attached to the surface using oxygen radicals generated from the titanium dioxide. In the anti-reflection films described in Patent Document 1 and Patent Document 2, the third layer containing titanium dioxide is covered by a fourth layer that forms the surface of the anti-reflection film. To effectively transport oxygen radicals generated in the third layer to the surface of the anti-reflection film, the fourth layer is preferably thin. Furthermore, to increase the amount of oxygen radicals generated, the third layer is preferably thicker.

[0012] On the other hand, considering the practicality as an anti-reflection film, for example, in order to achieve an average reflectivity of less than 1% in the wavelength range of 400nm to 700nm, it is preferred that the thickness of the fourth layer comprising silicon dioxide constituting the surface of the anti-reflection film is greater than 20nm, and the thickness of the third layer comprising titanium dioxide adjacent to the fourth layer is less than 150nm.

[0013] In the antireflection film described in Patent Document 1, the fourth layer composed of silicon dioxide is 90 nm thick, and the third layer composed of titanium dioxide is 120 nm thick. In this case, oxygen free radicals are insufficient, and the self-cleaning effect sufficient to maintain the hydrophilicity of the surface may not be achieved. In the antireflection film described in Patent Document 2, the fourth layer composed of silicon dioxide is 90 nm thick, and the third layer composed of titanium dioxide is 240 nm thick. In this case, the band with an average reflectivity of less than 1% is narrowed, potentially limiting its practicality as an antireflection film.

[0014] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an antireflection film and an optical component capable of achieving both improvement in reflectivity characteristics and maintenance of surface hydrophilicity.

[0015] Means for solving technical problems

[0016] An anti-reflection film according to one embodiment of the present invention is an anti-reflection film provided on an optical substrate, comprising: a reflectance adjustment film comprising a first layer, a second layer arranged on the surface side of the anti-reflection film relative to the first layer and having a higher refractive index than the first layer, and a third layer arranged on the surface side relative to the second layer and having a lower refractive index than the second layer, and the thickness from the surface is greater than 20 nm and less than 150 hm; and a photocatalytic film comprising one or more photocatalytically active layers containing titanium dioxide, the layers being provided between the reflectance adjustment film and the optical substrate and the interface on the reflectance adjustment film side being provided at a position less than 150 nm from the surface, and the total thickness of the photocatalytically active layers being greater than 350 nm and less than 1000 nm.

[0017] In the optical component according to one aspect of the present invention, the antireflection film is provided on an optical substrate.

[0018] Effects of the Invention

[0019] According to the present invention, it is possible to provide an antireflection film and an optical component capable of achieving both improvement in reflectance characteristics and maintenance of surface hydrophilicity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram for explaining an example of an optical component according to an embodiment of the present invention.

[0021] Figure 2 yes Figure 1 Schematic diagram of a modified example of an optical component.

[0022] Figure 3 yes Figure 1 Schematic diagram of another modified example of the optical component.

[0023] Figure 4 Schematic diagram showing the crystal structure of anatase structure of titanium dioxide.

[0024] Figure 5 This is a graph showing the results of XRD measurement of a photocatalyst film containing titanium dioxide.

[0025] Figure 6 This is a graph showing the results of XRD measurement of a photocatalyst film containing titanium dioxide. DETAILED DESCRIPTION

[0026] Figure 1 The optical component 1 shown includes an optical base material 2 and an antireflection film 3 provided on the optical base material 2 .

[0027] The optical substrate 2 can be, for example, an optical element such as a lens, or a film, and its form is not particularly limited. Examples of lenses include vehicle-mounted lenses, surveillance camera lenses, interchangeable lenses, and television lenses. When the optical substrate 2 is a film, the optical component 1 is attached to the surface of an optical element such as a lens for use. Glass or resin is used as the material of the optical substrate 2. Examples of the resin include polycarbonate, cycloolefin, and polyimide. In relation to the method for producing the anti-reflection film described later, polyimide having excellent heat resistance and a glass transition temperature of 300°C or higher, preferably 350°C or higher is preferred.

[0028] The antireflection film 3 includes a reflectivity adjusting film 4 and a photocatalytic film 5 disposed between the reflectivity adjusting film 4 and the optical substrate 2. The photocatalytic film 5 generates oxygen radicals upon irradiation with light. The oxygen radicals generated in the photocatalytic film 5 decompose dirt adhering to the surface 4a of the reflectivity adjusting film 4, which is in contact with the ambient air. The self-cleaning effect provided by these oxygen radicals prevents the surface 4a from becoming hydrophobic.

[0029] The surface 4a is preferably formed of a hydrophilic material. Here, the surface 4a being "hydrophilic" means that the contact angle with water is 10° or less, and the contact angle is measured by the sessile drop method specified in JIS R 3257. Examples of the hydrophilic material forming the surface 4a include SiO2 (silicon dioxide) and the like.

[0030] The reflectance adjustment film 4 includes a first layer 10, a second layer 11 disposed on the surface 4a side of the first layer 10 and having a higher refractive index than the first layer 10, and a third layer 12 disposed on the surface 4a side of the second layer 11 and having a lower refractive index than the second layer 11. Examples of materials for forming the first layer 10 and the third layer 12 include low-refractive-index materials having a refractive index of 1.6 or less, such as SiO2, MgF2 (magnesium fluoride), Si3N4 (silicon nitride), and Al2O3 (aluminum oxide). Examples of materials for forming the second layer 11 having a relatively high refractive index include high-refractive-index materials having a refractive index of 1.8 or greater, such as TiO2 (titanium dioxide), ITO (tin-doped indium oxide), ZnO (zinc oxide), SnO2 (tin dioxide), In2O3 (indium oxide), Nb2O5 (niobium pentoxide), Ta2O5 (tantalum pentoxide), TiN (titanium nitride), and ZrO (zirconium oxide).

[0031] When the third layer 12 is formed of hydrophilic SiO2, as Figure 1 As shown, the surface 4a can be formed by the third layer 12. On the other hand, when the third layer 12 is formed of non-hydrophilic MgF2 or Al2O3, as shown in FIG. Figure 2 As shown, a hydrophilic surface layer 13 is provided on the surface 4 a side of the third layer 12 , and the surface 4 a is formed by the surface layer 13 .

[0032] From the viewpoint of making the surface 4a hydrophilic, the third layer 12 or the surface layer 13 forming the surface 4a may be formed into a porous shape having fine irregularities, but is preferably formed into a solid shape from the viewpoint of improving wear resistance.

[0033] Furthermore, an intermediate layer may be provided between the first layer 10 and the second layer 11. Examples of the intermediate layer include one having an intermediate refractive index between the refractive index of the first layer 10 and the refractive index of the second layer 11. Similarly, an intermediate layer may be provided between the second layer 11 and the third layer 12.

[0034] The thickness of each of the first layer 10, the second layer 11, and the third layer 12 can be appropriately set based on the refractive index of each layer, the wavelength range for suppressing reflection, and other factors. For example, when the first layer 10 and the third layer 12 contain SiO2, and the second layer 11 contains TiO2, and the average reflectivity within the wavelength range of 400 nm to 700 nm is less than 1%, the thickness of the first layer 10 is preferably 15 nm to 40 nm, the thickness of the second layer 11 is preferably 10 nm to 25 nm, and the thickness of the third layer 12 is preferably 20 nm to 100 nm. The overall thickness of the reflectivity adjustment film 4 is preferably 20 nm or greater and less than 150 nm. If the overall thickness of the reflectivity adjustment film 4 is less than 20 nm, it may not be possible to achieve a reflectivity characteristic with an average reflectivity of less than 1% within the wavelength range of 400 nm to 700 nm. Furthermore, if the thickness of the entire reflectance adjustment film 4 is 150 nm or more, the transport of oxygen radicals generated in the photocatalytic film 5 to the surface 4 a is hindered, and there is a possibility that the self-cleaning effect cannot be obtained.

[0035] The photocatalytic film 5 includes a photocatalytically active layer 14 containing TiO2 (titanium dioxide). The photocatalytically active layer 14 is as follows: Figure 1 The shown one layer can be only one layer, or Figure 3 When the photocatalytic film 5 includes a plurality of photocatalytically active layers 14, the material of the intermediate layer 15 between two adjacent photocatalytically active layers 14 can be exemplified by the above-mentioned high-refractive-index materials (such as ITO, ZnO, SnO, In, O, Nb, Ta, O, TiN, and ZrO) in addition to the above-mentioned low-refractive-index materials (such as SiO, MgF, and SiN) and TiO.

[0036] From the perspective of exhibiting a self-cleaning effect, the total thickness of the photocatalytically active layer 14 is 350 nm to 1000 nm, preferably 350 nm to 500 nm. Furthermore, from the perspective of efficiently transporting oxygen radicals generated in the photocatalytically active layer 14 to the surface 4 a, the interface 5 a on the reflectivity adjusting film 4 side of the photocatalytic film 5 is positioned at a position 150 nm or less from the surface 4 a.

[0037] The thicknesses of the layers forming the reflectivity adjustment film 4 and the photocatalytic film 5 were measured using an optical film thickness meter (built into the film forming machine described below). Furthermore, the film thickness of the sample was measured by cross-sectional TEM (Transmission Electron Microscope) observation, and the agreement between the optical film thickness meter and the TEM observation values ​​was confirmed within the range of -3 nm to +3 nm.

[0038] The crystal structure of TiO2 contained in the photocatalytic active layer 14 is preferably anatase. Compared with rutile TiO2, anatase TiO2 has excellent photocatalytic activity. Figure 4 As shown, the crystal structure of the anatase structure is a tetragonal system, and has a structure in which Ti is surrounded by 6 O atoms.

[0039] Furthermore, the TiO2 contained in the photocatalytically active layer 14 may be doped with at least one element selected from the group consisting of N (nitrogen), S (sulfur), Cr (chromium), Sb (antimony), and Ce (cerium). By doping with these elements, the photocatalytic activity of the photocatalytically active layer 14 can be further improved. The doping amount is preferably 0.01 mol% or more and 0.05 mol% or less in terms of the molar ratio of Ti to the doping element. A portion of the Ti ions on the surface of the TiO2 film are replaced by cations (Cr 3+ 、Sb 3+ 、Ce 3+ ) or the oxygen ions on the TiO2 film surface are partially replaced by anions (N, S (valences vary and therefore cannot be labeled)), which can enhance photocatalytic activity. However, when the doping element content is less than 0.01 mol%, it is not possible to expect the photocatalytic activity of the TiO2 film to be enhanced by the replacement of these ions. Furthermore, when the doping element content exceeds 0.05 mol%, the doping element aggregates on the TiO2 film surface, potentially reducing the photocatalytic activity of the TiO2 film.

[0040] The above-described antireflection film 3 is manufactured by sequentially forming a photocatalytic film 5 and a reflectivity adjustment film 4 on an optical substrate 2. The film formation can be performed using a vapor deposition method. The formation of a reflectivity adjustment film 4 comprising a first layer 10 of a low refractive index, such as SiO2, a second layer 11 of a high refractive index, such as TiO2, and a third layer 12 of a low refractive index, such as SiO2, by a vapor deposition method is well known. The formation of the photocatalytic film 5 will be described below.

[0041] Ti3O5 (titanium pentoxide) can be used as a vapor deposition material in forming the photocatalytic active layer 14 containing TiO2. Using Ti3O5 as a vapor deposition material allows the formation of a photocatalytic active layer 14 with fewer oxygen vacancies than when using TiO2 as a vapor deposition material.

[0042] When the TiO₂ contained in the photocatalytically active layer 14 is irradiated with light, electrons in the valence band are excited to the conduction band. The oxygen excited to the conduction band is then reduced by the electrons, generating oxygen free radicals. During this electron transition, oxygen vacancies form trap levels between the valence band and conduction band energy levels, trapping electrons excited to the conduction band in the oxygen vacancies. As a result, the number of electrons contributing to the generation of oxygen free radicals decreases, reducing photocatalytic activity. Using Ti₃O₅ as the deposition material can suppress the generation of oxygen vacancies and enhance the photocatalytic activity of the photocatalytically active layer 14.

[0043] The temperature of the optical substrate 2 is preferably set to 300°C or higher and 350°C or lower during the formation of the photocatalytically active layer 14. This promotes the formation of anatase-structured TiO2. If the temperature of the optical substrate 2 is too low (e.g., below 200°C), the formation of amorphous TiO2, which does not exhibit photocatalytic activity, is promoted. If the temperature of the optical substrate 2 is too high (e.g., above 400°C), the formation of rutile-structured TiO2 is promoted.

[0044] Furthermore, it is preferable to form the photocatalytic active layer 14 in an atmosphere in which oxygen is introduced, and the flow rate of oxygen is set to 100×1.69×10 -3 Pa·m 3 / sec or above and 120×1.69×10 -3 Pa·m 3 This can improve the crystallinity of the anatase-structured TiO 2 and further enhance the photocatalytic activity of the photocatalytically active layer 14 .

[0045] Furthermore, the photocatalytic film 5 formed on the optical substrate 2 is preferably annealed, with the temperature of the annealing atmosphere (hereinafter referred to as the annealing temperature) being set to 350°C to 400°C, and the annealing time being set to 2 hours to 6 hours. This can improve the sustainability of the photocatalytic activity of the photocatalytically active layer 14.

[0046] It is presumed that the continuation of the photocatalytic activity after annealing the photocatalytic film 5 is correlated with a reduction in the impurity energy levels contained in the TiO2. It is also believed that, similar to oxygen vacancy energy levels, the impurity energy levels contained in the TiO2 become trap energy levels during electron transitions generated in the TiO2, thereby reducing the photocatalytic activity of the photocatalytically active layer 14. In experiments conducted by the present inventors, electron paramagnetic resonance (ESR) measurements confirmed that annealing the photocatalytic film 5 under the aforementioned conditions reduced the impurity energy levels contained in the TiO2.

[0047] In addition, the continuous effect of the photocatalytic activity of the annealing-based photocatalytic active layer 14 is also affected by the annealing ambient gas. Compared with the case of annealing the photocatalytic film 5 in oxygen, the continuous effect of the photocatalytic activity can be improved by annealing the photocatalytic film 5 in air.

[0048] Moreover, when doping the TiO2 contained in the photocatalytic film 5 (photocatalytic active layer 14) with foreign elements (N, S, Cr, Sb, Ce), an ion implantation device can be used to dope a specimen with a TiO2 film formed thereon. For example, the doping method can use the method described in Japanese Patent Laid-Open No. 9-262482. Further, after doping the foreign elements, the reflectance adjustment film 4 is formed.

[0049] Hereinafter, experimental examples will be described. <00001T56><Crystal Structure of TiO2 Photocatalytic Film>

[0051] Using Ti3O5 as the evaporation material and a whiteboard glass (manufactured by FD110 HOYA Corporation) as the optical substrate, a single-layer photocatalytic film with a thickness of 300 nm containing TiO2 was formed on the optical substrate by electron beam evaporation. In addition, the film-forming machine used was ACE-1800 manufactured by SHINCRON C0., LTD. Moreover, the temperature of the optical substrate during the formation of the photocatalytic film was changed within the range from not heated to 400 °C, and at the same time, the oxygen flow rate introduced into the chamber of the film-forming machine was changed within the range from 0 to 120×1.69×10 -3 Pa·m 3 / sec, and the obtained photocatalytic film was subjected to X-ray diffraction (XRD: X-ray diffraction) measurement, and the crystal structure of TiO2 contained in the photocatalytic film was analyzed. The measurement device and measurement conditions used in the XRD measurement are as follows.

[0052] [ ● Device: RINT-2500 (manufactured by Rigaku Corporation)

[0053] ● Radiation source: Cu kα 55 kV, 280 mA

[0054] ● Optical system

[0055] Divergence slit (DS: Divergence Slit): 1.0° <00001:68> Scattering slit (SS: Scattering Slit): 1.0°

[0057] Receiving slit (RS: Receiving Slit): 0.3 mm

[0058] The analysis results of the crystal structure are shown in Table 1.

[0059] [Table 1]

[0060]

[0061] As shown in Table 1, when the temperature of the optical substrate during the formation of the photocatalytic film was set to 300°C or higher and 350°C or lower, anatase-structured TiO2 was obtained. Furthermore, when the amount of oxygen introduced during the formation of the photocatalytic film was set to 100×1.69×10 -3 Pa·m 3 / sec or above and 120×1.69×10 -3 Pa·m 3 / sec or less, a highly crystalline anatase TiO2 with excellent photocatalytic activity was obtained. Regarding the crystallinity of TiO2, the temperature of the optical substrate was set to 300 ° C and the amount of oxygen introduced was set to 70 × 1.69 × 10 -3 Pa·m 3 The XRD measurement results at 1000 nm / sec are shown in FIG. Figure 5 Similarly, the temperature of the optical substrate was set to 300°C and the amount of oxygen introduced was set to 100×1.69×10 -3 Pa·m 3 The XRD measurement results at 1000 nm / sec are shown in FIG. Figure 6 .

[0062] exist Figure 5 and Figure 6 In any of the XRD measurement results, the XRD peak position is consistent with the peak position of anatase TiO2 (literature value), but Figure 5 Compared with the XRD results shown in Figure 6 The XRD measurement results shown in FIG. 1 show that the baseline at the low angle side (2θ≤40°) decreases and the intensity of each peak increases. -3 Pa·m 3 / sec, the crystallinity of TiO2 is relatively high.

[0063] <Thickness Dependence of Photocatalytic Activity of Photocatalytic Film>

[0064] Next, the relationship between the photocatalytic activity and film thickness of the TiO2 photocatalytic film was evaluated. Using Ti3O5 as the evaporation material and white glass (FD110 manufactured by HOYA) as the optical substrate, a single-layer photocatalytic film containing TiO2 was formed on the optical substrate by electron beam evaporation. Furthermore, using SiO2 as the evaporation material, a SiO2 film with a thickness of 50nm was formed on the photocatalytic film by electron beam evaporation to produce an evaluation sample. In addition, the temperature of the optical substrate during the formation of the photocatalytic film was set to 300°C and 350°C, and the amount of oxygen introduced was set to 100×1.69×10 -3 Pa·m 3 / sec, the temperature of the optical substrate during the SiO2 film formation was set to be the same as that during the photocatalyst film formation, and the amount of oxygen introduced was set to 0.

[0065] Taking multiple evaluation samples in which the thickness of the photocatalytic film was changed in the range of 10nm to 500nm as the object, the contact angle of the SiO2 film on the sample surface with water was measured by the following steps, and the film thickness dependence of the photocatalytic activity of the photocatalytic film was evaluated based on the contact angle. In the measurement of the contact angle, first, a cotton swab was used to wipe the surface of the sample with car wax (trade name "NewWillson", manufactured by Willson). After 24 hours from the application of the wax, the wax applied to the sample surface was removed with a neutral detergent and water, and the contact angle θ1 of the sample surface with the wax removed with water was measured. In addition, the sample surface was irradiated with ultraviolet light, and the contact angle θ2 of the sample surface with water was measured again after irradiation. In addition, the light source of ultraviolet light used was a UV-B ultraviolet lamp 20WGL20SE manufactured by SAN KYO DENKI Co., Ltd., and the irradiation condition was set to a UV illuminance of 3mw / cm 2 , irradiation time 40 minutes (equivalent to 7.2J / cm 2 ). In addition, the contact angle measuring apparatus used was DM300 manufactured by Kyowa Interface Science Co., Ltd. Hereinafter, the above-mentioned contact angle measurement procedure is referred to as a WAX test.

[0066] The measurement results of the contact angle θ2 are shown in Table 2. The value of the contact angle θ2 in Table 2 is an average value of the measured values ​​obtained by measuring the contact angle three times for each sample.

[0067] [Table 2]

[0068]

[0069] The contact angle θ1 was 50° or greater for all evaluated samples. In contrast, as shown in Table 2, the contact angle θ2 after UV irradiation for samples with a photocatalytic film thickness of 350 nm or greater was 5° or less, indicating so-called super-hydrophilic properties. These measurement results indicate that in order for the self-cleaning effect of TiO2 contained in the photocatalytic film to manifest, a photocatalytic film thickness (total thickness of the photocatalytically active layer) of 350 nm or greater is required.

[0070] <Sustainability of Photocatalytic Activity of Photocatalytic Film>

[0071] Next, the aforementioned evaluation samples with a photocatalytic film thickness of 350 nm and 500 nm were annealed in air at varying annealing temperatures and times. Furthermore, the annealed samples were repeatedly subjected to the aforementioned WAX test. The sustainability of the photocatalytic activity of the photocatalytic film was evaluated based on the number of tests in which the contact angle with water on the sample surface after UV irradiation remained below 5°.

[0072] The evaluation results of the sustainability are shown in Table 3. The number of tests in Table 3 refers to the number of tests when the annealing time was 4 hours.

[0073] [Table 3]

[0074]

[0075] As shown in Table 3, annealing in air at a temperature between 350°C and 400°C improves the sustainability of the photocatalytic activity of the photocatalyst film. The appropriate annealing temperature depends on the thickness of the photocatalyst film. For a photocatalyst film thickness of 350 nm, the annealing temperature is preferably 350°C, while for a photocatalyst film thickness of 500 nm, the annealing temperature is preferably 400°C. The test times in Table 3 are for an annealing time of 4 hours. Similar results were obtained for annealing times between 2 and 6 hours.

[0076] <Reflectivity Characteristics and Self-Cleaning Function of Optical Components>

[0077] Next, make Figure 1 and Figure 2 The optical components shown in FIG. 1 and FIG. 2 were prepared, and the reflectivity characteristics and self-cleaning effect of the optical components were evaluated. The optical components of Experimental Examples 1, 2, 4 to 7 had Figure 1 In the structure shown, a single-layer photocatalytic film 5 containing TiO2 and a reflectivity adjustment film 4 are sequentially formed on an optical substrate 2. The reflectivity adjustment film 4 is composed of a first layer 10 containing SiO2, a second layer 11 containing TiO2, and a third layer 12 containing SiO2, in order from the optical substrate 2 side. In addition, the optical component of Experimental Example 3 has Figure 2In the structure shown, a single-layer photocatalytic film 5 comprising TiO2 and a reflectance adjustment film 4 are sequentially formed on an optical substrate 2. The reflectance adjustment film 4 is composed, from the optical substrate 2 side, of a first layer 10 comprising MgF2, a second layer 11 comprising TiO2, a third layer 12 comprising MgF2, and a surface layer 13 comprising SiO2. Furthermore, in the optical component of Experimental Example 8, a single-layer photocatalytic film 5 comprising TiO2 and a single-layer reflectance adjustment film 4 comprising SiO2 are sequentially formed on an optical substrate 2.

[0078] In the optical components of Experimental Examples 1 to 8, white plate glass (FD110 manufactured by HOYA) was commonly used as the optical substrate 2. Furthermore, the single-layer photocatalytic film 5 containing TiO2 was formed by using Ti3O5 as the vapor deposition material, and the temperature of the optical substrate 2 was set to 350°C and the oxygen introduction amount was set to 100×1.69×10 -3 Pa·m 3 / sec and was formed by electron beam evaporation. The photocatalytic film 5 formed on the optical substrate 2 was annealed in air at an annealing temperature of 350°C and an annealing time of 4 hours. The second layer 11 containing TiO2 of the reflectivity adjustment film 4 was formed by using Ti3O5 as the evaporation material, setting the temperature of the optical substrate 2 to 350°C and the oxygen introduction amount to 100×1.69×10 -3 Pa·m 3 / sec and were formed by electron beam evaporation. Furthermore, the first layer 10, third layer 12, and surface layer 13 of the reflectivity adjustment film 4, comprising SiO2, were formed by electron beam evaporation using SiO2 as the evaporation material, with the temperature of the optical substrate 2 set to 350°C and the oxygen introduction rate set to zero. Furthermore, the first layer 10 and third layer 12 of the reflectivity adjustment film 4, comprising MgF2, were formed by electron beam evaporation using MgF2 as the evaporation material, with the temperature of the optical substrate 2 set to 350°C and the oxygen introduction rate set to zero.

[0079] The reflectivity characteristics were evaluated based on the average reflectivity in the wavelength range of 400nm to 700nm and the presence or absence of pulsation (variation) in the reflectivity characteristic curve in the wavelength range of 400nm to 700nm, as well as the degree of pulsation. In addition, the average reflectivity is a value obtained by measuring the reflectivity of each wavelength at a wavelength interval of 1nm and dividing the total reflectivity value by the number of measurements. When the average reflectivity is 0.5% or less and there is no pulsation, it is rated A; when the average reflectivity is 1.0% or less and there is relatively weak pulsation, it is rated B; when the average reflectivity is 1.0% or less and there is relatively strong pulsation, it is rated C; and when the average reflectivity is greater than 1.0%, it is rated D. In addition, the self-cleaning effect was evaluated by performing the above-mentioned WAX test 10 times and based on the contact angle of water on the surface 4a of the reflectivity adjustment film 4 after ultraviolet light irradiation.

[0080] Table 4 shows the evaluation results of the reflectivity characteristics and the self-cleaning effect.

[0081] [Table 4]

[0082]

[0083] As shown in Table 4, in the optical component of Experimental Example 4, where the total thickness of the reflectance adjusting film 4 was 315 nm, the interface 5a of the photocatalyst film 5 on the reflectance adjusting film 4 side was located at a position 315 nm deeper than 150 nm from the surface 4a of the reflectance adjusting film 4. In this case, the transport of oxygen radicals generated in the photocatalyst film 5 to the surface 4a was hindered, reducing the self-cleaning effect. As a result, the contact angle at the surface 4a was 22.4°. Furthermore, in the optical component of Experimental Example 5, where the photocatalyst film 5 had a thickness of 200 nm, insufficient oxygen radicals were generated in the photocatalyst film 5, reducing the self-cleaning effect. As a result, the contact angle at the surface 4a was 15.2°. Furthermore, in the optical component of Experimental Example 8, where the reflectance adjusting film 4 consisted solely of the first layer 10 containing SiO2, the average reflectance in the wavelength range of 400 to 700 nm was 1.3%, indicating a lack of practicality as an antireflection film. On the other hand, in the optical components of Experiments 1 to 3, 6, and 7, where the total thickness of the reflectance adjusting film 4 was 20 nm or more and less than 150 nm, the interface 5a of the photocatalytic film 5 was located at a position 150 nm or less from the surface 4a, and the thickness of the photocatalytic film 5 was 350 nm or more and 1000 nm or less, the average reflectivity in the wavelength range of 400 to 700 nm was 1.0% or less, demonstrating practical application as an antireflection film. Furthermore, the contact angle of the surface 4a was 5° or less, maintaining the hydrophilicity of the surface 4a through a self-cleaning action.

[0084] In particular, in the optical components of Experimental Examples 1 to 3, where the thickness of the photocatalytic film 5 was between 350 nm and 500 nm, the average reflectivity within the wavelength range of 400 to 700 nm was 0.5% or less, and the reflectivity characteristic curve within the wavelength range of 400 to 700 nm was a flat curve with no pulsation. Based on these results, it is preferable that the thickness of the photocatalytic film 5 be between 350 nm and 500 nm, thereby improving the reflectivity characteristics of the anti-reflection film 3.

[0085] <TiO2 Crystal Structure and Self-Cleaning Effect of Photocatalytic Film>

[0086] The optical components of Experimental Examples 9 to 11 all had the same structure as the optical component of Experimental Example 2. However, the film forming conditions of the single-layer photocatalytic film 5 containing TiO2 were different in each experimental example. In the optical component of Experimental Example 9, the temperature of the optical substrate 2 was set to 350°C and the amount of oxygen introduced was set to 100×1.69×10 -3 Pa·m 3 / sec and the film was formed by electron beam evaporation. In the optical component of Experimental Example 10, the temperature of the optical substrate 2 was set to 400°C and the amount of oxygen introduced was set to 100×1.69×10 -3 Pa·m 3 / sec and the film was formed by electron beam evaporation. In the optical component of Experimental Example 11, the temperature of the optical substrate 2 was set to 200°C and the amount of oxygen introduced was set to 100×1.69×10 - 3 Pa·m 3 / sec and film formation was performed by electron beam evaporation. XRD analysis of the crystal structure of TiO2 contained in the thus-formed photocatalytic film 5 revealed that the optical component of Experimental Example 9 had an anatase structure, the optical component of Experimental Example 10 had a rutile structure, and the optical component of Experimental Example 11 had an amorphous structure. The aforementioned WAX test was performed 10 times on the optical components of Experimental Examples 9 to 11, and the correlation between the TiO2 crystal structure and the self-cleaning effect was evaluated based on the contact angle of water on the surface 4a of the reflectivity adjustment film 4 after ultraviolet light irradiation.

[0087] Table 5 shows the evaluation results of the correlation between TiO2 crystal structure and self-cleaning effect.

[0088] [Table 5]

[0089]

[0090] As shown in Table 5, in the optical component of Experimental Example 10, in which the photocatalytic film 5 contained rutile TiO2, the contact angle of the surface 4a of the reflectivity adjusting film 4 was 30°. In the optical component of Experimental Example 11, in which the photocatalytic film 5 contained amorphous TiO2, the contact angle of the surface 4a of the reflectivity adjusting film 4 was 50°. In contrast, in the optical component of Experimental Example 9, in which the photocatalytic film 5 contained anatase TiO2, the contact angle of the surface 4a of the reflectivity adjusting film 4 was 4.8°, indicating that the hydrophilicity of the surface 4a was maintained through the self-cleaning effect. These results indicate that the anatase crystal structure of the TiO2 contained in the photocatalytic film 5 is preferred, as this can enhance the photocatalytic activity of the photocatalytic film 5 and strengthen the self-cleaning effect.

[0091] <Doping and self-cleaning effects on photocatalytic films>

[0092] The optical components of Experimental Examples 12 to 14 all had the same structure as the optical component of Experimental Example 2. However, the single-layer photocatalytic film 5 containing TiO2 was doped with a different element in each experimental example: N (nitrogen) was doped in the optical component of Experimental Example 12, Cr (chromium) was doped in the optical component of Experimental Example 13, and Ce (cerium) was doped in the optical component of Experimental Example 14. The optical components of Experimental Examples 12 to 14 were subjected to the aforementioned WAX test 10 times, and the correlation between the doping element and the self-cleaning effect was evaluated based on the contact angle of water on the surface 4a of the reflectivity adjustment film 4 after ultraviolet light irradiation.

[0093] Table 6 shows the evaluation results of the correlation between the doping element and the self-cleaning effect.

[0094] [Table 6]

[0095]

[0096] As shown in Table 6, the average reflectivity of the optical components in Experimental Example 12 (doped with N), Experimental Example 13 (doped with Cr), and Experimental Example 14 (doped with Ce) in the wavelength range of 400 to 700 nm was lower than that of the optical component in Experimental Example 2, and the contact angle of the surface 4a of the reflectivity adjustment film 4 was also lower. Based on the above results, the TiO2 contained in the photocatalytic film 5 can be doped with N, Cr, and Ce. By doping with these elements, the photocatalytic activity of the photocatalytic film 5 can be enhanced, thereby strengthening the self-cleaning effect. Furthermore, it is believed that when S (sulfur) is doped, similar to the case of N doping, a portion of the oxygen ions in the TiO2 are replaced by S ions, thereby enhancing the photocatalytic activity of the photocatalytic film 5. Furthermore, when Sb (antimony) is doped, similar to the case of Cr and Ce doping, a portion of the Ti ions are replaced by Sb ions, thereby enhancing the photocatalytic activity of the photocatalytic film 5.

[0097] <Self-cleaning effect of multilayer photocatalytic film>

[0098] The optical components of Experimental Examples 15 to 17 had a photocatalytic film 5 and a reflectance adjustment film 4 formed in this order on an optical substrate 2. The photocatalytic film 5 consisted of, in order from the optical substrate 2 side, a first photocatalytically active layer 14 comprising TiO2, an intermediate layer 15 comprising SiO2, and a second photocatalytically active layer 14 comprising TiO2. The reflectance adjustment film 4 consisted of, in order from the optical substrate 2 side, a first layer 10 comprising SiO2, a second layer 11 comprising TiO2, and a third layer 12 comprising SiO2. However, the thickness of the intermediate layer 15 comprising SiO2 in the photocatalytic film 5 varied between the experimental examples, being 1 nm in the optical component of Experimental Example 15, 2 nm in the optical component of Experimental Example 16, and 3 nm in the optical component of Experimental Example 17.

[0099] In the optical components of Experimental Examples 15 to 17, white plate glass (FD110 manufactured by HOYA Co., Ltd.) was commonly used as the optical substrate 2. Furthermore, the first photocatalytic layer 14 and the second photocatalytic layer 14 containing TiO2 were formed using Ti3O5 as the vapor deposition material. The temperature of the optical substrate 2 was set to 350°C, and the amount of oxygen introduced was set to 100×1.69×10 -3 Pa·m 3 / sec and formed by electron beam evaporation. Furthermore, the intermediate layer 15 comprising SiO2 was formed by electron beam evaporation using SiO2 as the evaporation material, setting the temperature of the optical substrate 2 to 350°C and the oxygen introduction amount to 0. Furthermore, the photocatalytic film 5 formed on the optical substrate 2 was annealed in air at an annealing temperature of 350°C and an annealing time of 4 hours. Furthermore, the second layer 11 comprising TiO2 of the reflectivity adjustment film 4 was formed by using Ti3O5 as the evaporation material, setting the temperature of the optical substrate 2 to 350°C and the oxygen introduction amount to 100×1.69×10 -3 Pa·m 3 The first layer 10, the third layer 12, and the surface layer 13 of the reflectance adjustment film 4, which are composed of SiO2, were formed by electron beam deposition using SiO2 as the deposition material, with the temperature of the optical substrate 2 set to 350°C and the oxygen introduction amount set to 0.

[0100] The WAX ​​test was performed 10 times on the optical components of Experimental Examples 15 to 17, and the correlation between the thickness of the intermediate layer 15 of the photocatalytic film 5 and the self-cleaning effect was evaluated based on the contact angle of water on the surface 4a of the reflectivity adjustment film 4 after ultraviolet light irradiation.

[0101] Table 7 shows the evaluation results of the correlation between the thickness of the intermediate layer 15 and the self-cleaning effect.

[0102] [Table 7]

[0103]

[0104] As shown in Table 7, the photocatalytic films 5 of the optical components of Experimental Examples 15 to 17 were substantially identical to those of the optical component of Experimental Example 2, except for whether the photocatalytic film 5 was divided into two photocatalytically active layers 14 via the intermediate layer 15. The average reflectance of the optical components of Experimental Examples 15 to 17 over a wavelength range of 400 to 700 nm was 0.5% or less, similar to that of the optical component of Experimental Example 2. Furthermore, the contact angle of the surface 4a of the reflectivity adjustment film 4 of the optical components of Experimental Examples 15 to 17 was 4.8°, similar to that of the optical component of Experimental Example 2. These results demonstrate that the photocatalytic film 5 can include two photocatalytically active layers 14 via the intermediate layer 15.

[0105] As described above, the anti-reflection film disclosed in this specification is an anti-reflection film arranged on an optical substrate, which comprises: a reflectance adjustment film, comprising a first layer, a second layer arranged on the surface side of the anti-reflection film relative to the above-mentioned first layer and having a higher refractive index than the above-mentioned first layer, and a third layer arranged on the above-mentioned surface side relative to the above-mentioned second layer and having a lower refractive index than the above-mentioned second layer, and the thickness from the above-mentioned surface is greater than 20nm and less than 150nm; and a photocatalytic film, comprising one or more photocatalytic active layers containing titanium dioxide, arranged between the above-mentioned reflectance adjustment film and the above-mentioned optical substrate and the interface on the above-mentioned reflectance adjustment film side is arranged at a position less than 150nm from the above-mentioned surface, and the total thickness of the above-mentioned photocatalytic active layers is greater than 35Ohm and less than 1000nm.

[0106] Furthermore, in the antireflection film disclosed in this specification, the total thickness of the photocatalytic active layers is 350 nm to 500 nm.

[0107] Furthermore, in the antireflection film disclosed in this specification, the photocatalytic active layer included in the photocatalytic film is a single layer.

[0108] Furthermore, in the antireflection film disclosed in this specification, the crystal structure of titanium dioxide contained in the photocatalytic active layer is an anatase structure.

[0109] Furthermore, the antireflection film disclosed in this specification is an antireflection film in which the photocatalytic active layer further contains one or more elements selected from the group consisting of nitrogen, sulfur, chromium, antimony, and cerium.

[0110] Furthermore, in the antireflection film disclosed in this specification, the third layer includes silicon dioxide and forms the surface.

[0111] Furthermore, in the optical component disclosed in this specification, the antireflection film is provided on an optical substrate.

[0112] Furthermore, in the optical component disclosed in this specification, the optical substrate is a lens.

[0113] Industrial applicability

[0114] The present invention can be used for optical components such as lenses and covers of cameras installed outdoors, such as surveillance cameras and vehicle-mounted cameras.

[0115] The embodiments of the present invention are described in detail above, but this is only an example, and the present invention can be implemented in various ways without departing from the scope of its purpose. This application is based on Japanese patent application (Japanese patent application 2017-079008) filed on April 12, 2017, the contents of which are incorporated herein by reference.

[0116] Explanation of symbols

[0117] 1-Optical component, 2-Optical substrate, 3-Anti-reflection film, 4-Reflectivity adjustment film, 4a-Surface, 5-Photocatalytic film, 5a-Interface, 10-1st layer, 11-2nd layer, 12-3rd layer, 14-Photocatalytic active layer, 15-Intermediate layer.

Claims

1. An anti-reflection film provided on an optical substrate, the anti-reflection film comprising: A reflectance adjustment film comprising a first layer, a second layer disposed on a surface side of the antireflection film relative to the first layer and having a higher refractive index than the first layer, and a third layer disposed on the surface side relative to the second layer and having a lower refractive index than the second layer, wherein the thickness from the surface is 70 nm; and A photocatalytic film comprising one or more photocatalytically active layers containing titanium dioxide, the photocatalytically active layers being disposed between the reflectivity adjustment film and the optical substrate, the reflectivity adjustment film-side interface being located at a position less than 150 nm from the surface, and the total thickness of the photocatalytically active layers being 364 nm. The material forming the first layer and the material forming the third layer are both SiO2, The material forming the second layer is TiO2, The crystal structure of titanium dioxide contained in the photocatalytic active layer is anatase structure.

2. An anti-reflection film provided on an optical substrate, the anti-reflection film comprising: A reflectance adjustment film comprising a first layer, a second layer disposed on a surface side of the antireflection film relative to the first layer and having a higher refractive index than the first layer, and a third layer disposed on the surface side relative to the second layer and having a lower refractive index than the second layer, wherein the thickness from the surface is 129 nm; and A photocatalytic film comprising one or more photocatalytically active layers containing titanium dioxide, the photocatalytically active layers being disposed between the reflectivity adjustment film and the optical substrate, the reflectivity adjustment film-side interface being located at a position less than 150 nm from the surface, and the total thickness of the photocatalytically active layers being 364 nm. The material forming the first layer and the material forming the third layer are both magnesium fluoride, and a hydrophilic surface layer is provided on the surface side of the third layer. The material forming the second layer is TiO2, The crystal structure of titanium dioxide contained in the photocatalytic active layer is anatase structure.

3. An anti-reflection film provided on an optical substrate, the anti-reflection film comprising: A reflectance adjustment film comprising a first layer, a second layer disposed on a surface side of the antireflection film relative to the first layer and having a higher refractive index than the first layer, and a third layer disposed on the surface side relative to the second layer and having a lower refractive index than the second layer, wherein the thickness from the surface is 130 nm; and A photocatalytic film comprising one or more photocatalytically active layers containing titanium dioxide, disposed between the reflectivity adjustment film and the optical substrate, with the interface on the reflectivity adjustment film side being located at a position less than 150 nm from the surface, and the total thickness of the photocatalytically active layers being 486 nm. The material forming the first layer and the material forming the third layer are both SiO2, The material forming the second layer is TiO2, The crystal structure of titanium dioxide contained in the photocatalytic active layer is anatase structure.

4. An anti-reflection film provided on an optical substrate, the anti-reflection film comprising: A reflectance adjustment film comprising a first layer, a second layer disposed on a surface side of the antireflection film relative to the first layer and having a higher refractive index than the first layer, and a third layer disposed on the surface side relative to the second layer and having a lower refractive index than the second layer, wherein the thickness from the surface is 130 nm; and A photocatalytic film comprising one or more photocatalytically active layers containing titanium dioxide, disposed between the reflectivity adjustment film and the optical substrate, with the interface on the reflectivity adjustment film side being located at a position less than 150 nm from the surface, and the total thickness of the photocatalytically active layers being 486 nm. The material forming the first layer and the material forming the third layer are both SiO2, The material forming the second layer is TiO2, The photocatalytic active layer also contains chromium.

5. An anti-reflection film provided on an optical substrate, the anti-reflection film comprising: A reflectance adjustment film comprising a first layer, a second layer disposed on a surface side of the antireflection film relative to the first layer and having a higher refractive index than the first layer, and a third layer disposed on the surface side relative to the second layer and having a lower refractive index than the second layer, wherein the thickness from the surface is 130 nm; and A photocatalytic film comprising one or more photocatalytically active layers containing titanium dioxide, disposed between the reflectivity adjustment film and the optical substrate, with the interface on the reflectivity adjustment film side being located at a position less than 150 nm from the surface, and the total thickness of the photocatalytically active layers being 486 nm. The material forming the first layer and the material forming the third layer are both SiO2, The material forming the second layer is TiO2, The photocatalytic active layer further contains cerium.

6. The antireflection film according to any one of claims 1 to 5, wherein The photocatalytic active layer contained in the photocatalytic film is multi-layered.

7. The anti-reflection film according to any one of claims 1 to 5, wherein The photocatalytic active layer contained in the photocatalytic film is a single layer.

8. The anti-reflection film according to any one of claims 1 to 5, wherein In the photocatalytic active layer, the content of chromium or cerium is 0.01 mol % or more and 0.05 mol % or less in terms of a molar ratio of Ti to chromium or cerium.

9. The antireflection film according to any one of claims 1 to 5, wherein The third layer forms the porous surface having fine irregularities.

10. The anti-reflection film according to any one of claims 1 to 5, wherein The third layer forms the solid surface.

11. The anti-reflection film according to any one of claims 1 to 5, wherein The third layer forms the surface.

12. The anti-reflection film according to claim 8, wherein The third layer forms the surface. 13 . An optical component comprising an optical substrate and the antireflection film according to claim 1 provided on the optical substrate.

14. The optical component according to claim 13, wherein The optical substrate is a lens.

15. The method for producing an anti-reflection film according to claim 1, wherein the anti-reflection film is provided on an optical substrate, and the anti-reflection film comprises: A reflectance adjustment film comprising a first layer, a second layer disposed on a surface side of the antireflection film relative to the first layer and having a higher refractive index than the first layer, and a third layer disposed on the surface side relative to the second layer and having a lower refractive index than the second layer, wherein the thickness from the surface is 70 nm; and A photocatalytic film comprising one or more photocatalytically active layers containing titanium dioxide, the photocatalytically active layers being disposed between the reflectivity adjustment film and the optical substrate, the reflectivity adjustment film-side interface being located at a position less than 150 nm from the surface, and the total thickness of the photocatalytically active layers being 364 nm. The photocatalytic film is manufactured by a manufacturing method comprising the following steps: The process of heating clear glass to 350°C, Oxygen is converted to 100×1.69×10 -3 Pa·m 3 / sec import volume import process, The process of forming a film of Ti3O5 as a vapor deposition material on the white glass by electron beam vapor deposition, The film formed on the white plate glass is annealed in air at an annealing temperature of 350° C. and an annealing time of 4 hours. The second layer of the reflectance adjustment film is manufactured by a manufacturing method comprising the following steps: The process of heating clear glass to 350°C, Oxygen is converted to 100×1.69×10 -3 Pa·m 3 / sec import volume import process, The process of forming a film by electron beam evaporation using Ti3O5 as the evaporation material, The first layer and the third layer of the reflectance adjustment film are manufactured by a manufacturing method including the following steps: The process of heating clear glass to 350°C, A step of introducing oxygen at an introduction rate of 0, A process of forming a film by electron beam evaporation using SiO2 as the evaporation material.

16. The method for producing an antireflection film according to claim 2, wherein the antireflection film is provided on an optical substrate, and the antireflection film comprises: A reflectance adjustment film comprising a first layer, a second layer disposed on a surface side of the antireflection film relative to the first layer and having a higher refractive index than the first layer, and a third layer disposed on the surface side relative to the second layer and having a lower refractive index than the second layer, wherein the thickness from the surface is 129 nm; and A photocatalytic film comprising one or more photocatalytically active layers containing titanium dioxide, the photocatalytically active layers being disposed between the reflectivity adjustment film and the optical substrate, the reflectivity adjustment film-side interface being located at a position less than 150 nm from the surface, and the total thickness of the photocatalytically active layers being 364 nm. The photocatalytic film is manufactured by a manufacturing method comprising the following steps: The process of heating clear glass to 350°C, Oxygen is converted to 100×1.69×10 -3 Pa·m 3 / sec import volume import process, The process of forming a film of Ti3O5 as a vapor deposition material on the white glass by electron beam vapor deposition, The film formed on the white plate glass is annealed in air at an annealing temperature of 350° C. and an annealing time of 4 hours. The second layer of the reflectance adjustment film is manufactured by a manufacturing method comprising the following steps: The process of heating clear glass to 350°C, Oxygen is converted to 100×1.69×10 -3 Pa·m 3 / sec import volume import process, The process of forming a film by electron beam evaporation using Ti3O5 as the evaporation material, The first layer and the third layer of the reflectance adjustment film are manufactured by a manufacturing method including the following steps: The process of heating clear glass to 350°C, A step of introducing oxygen at an introduction rate of 0, The process of forming a film by electron beam deposition using MgF2 as the deposition material.

17. The method for producing an anti-reflection film according to claim 3, wherein the anti-reflection film is provided on an optical substrate, and the anti-reflection film comprises: A reflectance adjustment film comprising a first layer, a second layer disposed on a surface side of the antireflection film relative to the first layer and having a higher refractive index than the first layer, and a third layer disposed on the surface side relative to the second layer and having a lower refractive index than the second layer, wherein the thickness from the surface is 130 nm; and A photocatalytic film comprising one or more photocatalytically active layers containing titanium dioxide, disposed between the reflectivity adjustment film and the optical substrate, with the interface on the reflectivity adjustment film side being located at a position less than 150 nm from the surface, and the total thickness of the photocatalytically active layers being 486 nm. The photocatalytic film is manufactured by a manufacturing method comprising the following steps: The process of heating clear glass to 350°C, Oxygen is converted to 100×1.69×10 -3 Pa·m 3 / sec import volume import process, The process of forming a film of Ti3O5 as a vapor deposition material on the white glass by electron beam vapor deposition, The film formed on the white plate glass is annealed in air at an annealing temperature of 350° C. and an annealing time of 4 hours. The second layer of the reflectance adjustment film is manufactured by a manufacturing method comprising the following steps: The process of heating clear glass to 350°C, Oxygen is converted to 100×1.69×10 -3 Pa·m 3 / sec import volume import process, The process of forming a film by electron beam evaporation using Ti3O5 as the evaporation material, The first layer and the third layer of the reflectance adjustment film are manufactured by a manufacturing method including the following steps: The process of heating clear glass to 350°C, A step of introducing oxygen at an introduction rate of 0, A process of forming a film by electron beam evaporation using SiO2 as the evaporation material.

18. The method for producing an anti-reflection film according to claim 4, wherein the anti-reflection film is provided on an optical substrate, and the anti-reflection film comprises: A reflectance adjustment film comprising a first layer, a second layer disposed on a surface side of the antireflection film relative to the first layer and having a higher refractive index than the first layer, and a third layer disposed on the surface side relative to the second layer and having a lower refractive index than the second layer, wherein the thickness from the surface is 130 nm; and A photocatalytic film comprising one or more photocatalytically active layers containing titanium dioxide, disposed between the reflectivity adjustment film and the optical substrate, with the interface on the reflectivity adjustment film side being located at a position less than 150 nm from the surface, and the total thickness of the photocatalytically active layers being 486 nm. The photocatalytic film is manufactured by a manufacturing method comprising the following steps: The process of heating clear glass to 350°C, Oxygen is converted to 100×1.69×10 -3 Pa·m 3 / sec import volume import process, The process of forming a film of Ti3O5 as a vapor deposition material on the white glass by electron beam vapor deposition, The film formed on the white plate glass is annealed in air at an annealing temperature of 350° C. and an annealing time of 4 hours. The chromium doping process The second layer of the reflectance adjustment film is manufactured by a manufacturing method comprising the following steps: The process of heating clear glass to 350°C, Oxygen is converted to 100×1.69×10 -3 Pa·m 3 / sec import volume import process, The process of forming a film by electron beam evaporation using Ti3O5 as the evaporation material, The first layer and the third layer of the reflectance adjustment film are manufactured by a manufacturing method including the following steps: The process of heating clear glass to 350°C, A step of introducing oxygen at an introduction rate of 0, A process of forming a film by electron beam evaporation using SiO2 as the evaporation material.

19. The method for producing an anti-reflection film according to claim 5, wherein the anti-reflection film is provided on an optical substrate, and the anti-reflection film comprises: A reflectance adjustment film comprising a first layer, a second layer disposed on a surface side of the antireflection film relative to the first layer and having a higher refractive index than the first layer, and a third layer disposed on the surface side relative to the second layer and having a lower refractive index than the second layer, wherein the thickness from the surface is 130 nm; and A photocatalytic film comprising one or more photocatalytically active layers containing titanium dioxide, disposed between the reflectivity adjustment film and the optical substrate, with the interface on the reflectivity adjustment film side being located at a position less than 150 nm from the surface, and the total thickness of the photocatalytically active layers being 486 nm. The photocatalytic film is manufactured by a manufacturing method comprising the following steps: The process of heating clear glass to 350°C, Oxygen is converted to 100×1.69×10 -3 Pa·m 3 / sec import volume import process, The process of forming a film of Ti3O5 as a vapor deposition material on the white glass by electron beam vapor deposition, The film formed on the white plate glass is annealed in air at an annealing temperature of 350° C. and an annealing time of 4 hours. The cerium doping process, The second layer of the reflectance adjustment film is manufactured by a manufacturing method comprising the following steps: The process of heating clear glass to 350°C, Oxygen is converted to 100×1.69×10 -3 Pa·m 3 / sec import volume import process, The process of forming a film by electron beam evaporation using Ti3O5 as the evaporation material, The first layer and the third layer of the reflectance adjustment film are manufactured by a manufacturing method including the following steps: The process of heating clear glass to 350°C, A step of introducing oxygen at an introduction rate of 0, A process of forming a film by electron beam evaporation using SiO2 as the evaporation material.

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