Optical product

Abstract

The present application provides an optical product having a film with a fine concavo-convex structure of a material other than aluminum or a compound thereof. An optical product (1) includes a substrate (2) and an optical film (4) formed on a film formation surface (F) thereof. The optical film (4) has an Al2O3 layer (12) which is an Al2O3 layer disposed on the substrate (2) side, and a SiO2 layer (14) which is a SiO2 layer having a fine concavo-convex structure. A method for manufacturing the optical product (1) includes a step of forming an Al-based manufacturing intermediate film which is aluminum, an aluminum alloy, or a compound of aluminum on the substrate (2), and a step of immersing the substrate (2) with the Al-based manufacturing intermediate film in an aqueous solution of silica. The concentration of the silica in the aqueous solution is 10 mg / l or less.

Description

[0001] This application is a divisional application, which is the Chinese national application number 202180057077.0, filed on December 14, 2021, and entitled "Optical Product and Method for Manufacturing Optical Product". Technical Field

[0002] This invention relates to an optical product having a film with micro-uneven texture and a method for manufacturing the optical product. Background Technology

[0003] Patent document 1 (Japanese Patent Application Publication No. 2012-198330) describes a layer of aluminum or its compound with a fine uneven structure formed on the outermost surface of a substrate having a curved surface by vapor phase film formation and hydrothermal treatment at a temperature above 60°C and below boiling point.

[0004] The average height of the protrusions in this concave-convex structure is between 5 and 1000 nm.

[0005] In this micro-uneven film (moth's eye), the density decreases from the substrate side to the air side. Consequently, the refractive index of the film gradually changes. Therefore, this film eliminates optical interfaces, or functions similarly to a low-refractive-index thin film. Through these effects, the film exhibits an anti-reflective effect and can be used as an anti-reflective coating.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2012-198330 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] As mentioned above, it is known that aluminum or its compounds form fine, uneven structures.

[0011] However, the formation of fine bumps and dents in other materials, especially silicon dioxide (SiO2), is not well known.

[0012] Therefore, the main objective of this invention is to provide an optical product having a film with a micro-uneven structure made of a material other than aluminum or its compounds.

[0013] In addition, another major objective of the present invention is to provide a method for manufacturing an optical product that can be easily made into an optical product having a film with a micro-uneven structure made of a material other than aluminum or its compounds.

[0014] Methods for solving problems

[0015] To achieve the above objectives, an optical product is provided, comprising: a substrate; and an optical film formed directly or indirectly on the film-forming surface of the substrate, wherein the optical film comprises: an Al2O3 layer, which is an Al2O3 layer disposed on the substrate side; and a SiO2 layer, which is a SiO2 layer having a micro-uneven structure.

[0016] In addition, to achieve the above objective, a method for manufacturing an optical product is provided, comprising: a step of forming an Al-based intermediate film, which is aluminum, an aluminum alloy, or an aluminum compound, on a substrate; and a step of immersing the substrate with the Al-based intermediate film in an aqueous solution of silica, wherein the concentration of silica in the aqueous solution is 10 mg / L or less.

[0017] Invention Effects

[0018] The main advantage of this invention is that it provides an optical product having a film with a micro-uneven structure made of a material other than aluminum or its compounds.

[0019] In addition, another major advantage of the present invention is that it provides a method for manufacturing an optical product that can be easily made into an optical product having a film with a micro-uneven structure made of a material other than aluminum or its compounds. Attached Figure Description

[0020] Figure 1 This is a schematic cross-sectional view of the optical product of the present invention.

[0021] Figure 2 yes Figure 1 A schematic cross-sectional view of an intermediate component used in the manufacture of optical products.

[0022] Figure 3 (A) to (F) are Figure 1 A schematic diagram of the manufacturing method of optical products.

[0023] Figure 4 This is a graph of the single-sided reflectivity under vertical incidence in Example 1.

[0024] Figure 5 This is a graph of the transmittance of vertically incident light in Example 1.

[0025] Figure 6 It is a graph showing the reflectivity of light from both sides at various incident angles θ in Example 1.

[0026] Figure 7 This is a graph showing the dependence of the incident angle on the reflectivity of both sides in Example 1.

[0027] Figure 8 It is a graph of the spectrum of characteristic X-rays in the same observation object as in Example 1.

[0028] Figure 9 yes Figure 8 The observed image of the TEM in the observed object.

[0029] Figure 10 yes Figure 8 Overlapping images of C-Kα rays in the observed object.

[0030] Figure 11 yes Figure 8 Overlapping images of O-Kα rays in the observed object.

[0031] Figure 12 yes Figure 8 Overlapping images of Al-Kα rays in the observed object.

[0032] Figure 13 yes Figure 8 Overlapping images of Si-Kα rays in the observed object.

[0033] Figure 14 These are graphs of the single-sided reflectivity under vertical incidence in Examples 2-6.

[0034] Figure 15 It is the same as in Examples 7-11. Figure 14 The same diagram.

[0035] Figure 16 It is the same as in Examples 12-16. Figure 14 The same diagram.

[0036] Figure 17 It is the same as in Examples 17-20. Figure 14 The same diagram.

[0037] Figure 18 It is the same as in Examples 21-26. Figure 14 The same diagram.

[0038] Figure 19 It is in Examples 27-31 and Figure 14 The same diagram.

[0039] Figure 20 The examples 32-37 and Comparative Example 1 are related to... Figure 14 The same diagram.

[0040] Figure 21 These are graphs of single-sided reflectance at vertical incidence in Examples 2, 7, 10, 15, and 18, where the temperatures of the solutions used as the impregnation destination during manufacturing are different.

[0041] Figure 22 The graph shows the average reflectance in Examples 2, 7, 10, 15, and 18.

[0042] Figure 23 This is a graph showing the relationship between the average reflectance (vertical axis) and the silica concentration (horizontal axis) of the solution in Examples 32-37 and Comparative Example 1. Detailed Implementation

[0043] Hereinafter, examples of embodiments of the present invention will be described with appropriate use of the accompanying drawings.

[0044] It should be noted that the present invention is not limited to the following examples.

[0045] [Composition, etc.]

[0046] like Figure 1 As shown, the optical product 1 of the present invention includes a substrate 2 and an optical film 4 formed on the film-forming surface F of the substrate 2. It should be noted that the thickness of the optical film 4 is exaggerated relative to the thickness of the substrate 2 in the accompanying drawings.

[0047] Optical product 1 is used as an anti-reflective component with light transmission. That is, in optical product 1, the intensity of reflected light R1 relative to the intensity of incident light I1 (incident angle θ) directed to optical product 1 can be suppressed by optical film 4.

[0048] It should be noted that, in Figure 1 The diagram shows the transmitted light I2, which is the light transmitted from the incident light I1 to a surface opposite to the incident surface, and the reflected light R2, which is the light reflected from the incident light I1 to that surface. Additionally, the optical product 1 can also be used in components other than anti-reflective components.

[0049] Substrate 2 is the basis for forming optical product 1, and here it is plate-shaped (substrate). Substrate 2 is transparent, and the transmittance of visible light (wavelength above 400nm and below 750nm) on substrate 2 is approximately 100%. It should be noted that the shape of substrate 2 can be flat, curved, or block-shaped, or any other shape other than plate-shaped.

[0050] As the material of substrate 2, plastic is used, and here polycarbonate resin (PC) is used as a thermosetting resin. It should be noted that the material of substrate 2 is not limited to PC, and can be, for example, polyurethane resin, thiolated polyurethane resin, cyclosulfide resin, polyester resin, acrylic resin, polyethersulfone resin, poly4-methylpentene-1 resin, diethylene glycol dielyl carbonate resin, or combinations thereof. Furthermore, the material of substrate 2 can be other than plastics such as glass.

[0051] The film-forming surface F of the substrate 2 is disposed on both the surface and the back side, and the optical film 4 is directly disposed on both the surface and the back side. It should be noted that the optical film 4 can be disposed on either the surface or the back side, or it can be disposed on three or more surfaces in a blocky substrate 2, etc. Furthermore, an intermediate film such as a hard coating film can be disposed between at least one of the optical films 4 and the substrate 2. When such an intermediate film is disposed, the optical film 4 is indirectly formed on the substrate 2.

[0052] The optical film 4 on the back side has the same structure as the optical film 4 on the surface. The optical film 4 on the surface will be described below, and the description of the optical film 4 on the back side will be omitted as appropriate.

[0053] The optical film 4, counting from the side of the substrate 2 (the same applies below), has an Al2O3 layer 12 made of aluminum oxide in the first layer and a SiO2 layer 14 made of silicon dioxide with a fine uneven structure in the second layer.

[0054] Alternatively, the optical film 4 may have an Al2O3 layer as the main component in the first layer, and a SiO2 layer 14 as the main component with a fine uneven structure in the second layer. In this case, the boundary between the first and second layers may sometimes be unclear. Furthermore, typically, in the first layer, the closer to the substrate 2, the higher the proportion of Al2O3; the farther away from the substrate 2, the higher the proportion of SiO2 relative to Al2O3. That is, in the film thickness direction, the proportion of SiO2 relative to Al2O3 in the first layer is directly proportional to the distance from the substrate 2. The first layer is independent of the material distribution and can be considered a thin film without a fine uneven structure. Alternatively, the first layer can be considered the basis (foundation) of the fine uneven structure. Alternatively, the first layer can be considered a thin film without a fine uneven structure, where the material gradually changes within the layer. Furthermore, the second layer can contain Al2O3 in a state where it is not a major component. For example, the second layer can have: a core (skeleton) with a fine, uneven structure mainly composed of Al2O3 and a capping layer mainly composed of SiO2 covering part or all of the core. The second layer is independent of the material distribution and can be considered as a layer with a fine, uneven structure.

[0055] The height of the SiO2 layer 14 is, for example, between 1 nm and 1000 nm (on the order of nanometers). The fine uneven structure in the SiO2 layer 14 is, for example, a villous structure, a pyramidal structure, or a sponge-like structure, or a combination thereof.

[0056] [Manufacturing methods, etc.]

[0057] Optical product 1 Figure 2 The manufacturing intermediate 20 shown is manufactured. The manufacturing intermediate 20 includes a substrate 2 and an Al-based manufacturing intermediate film 22 formed on the film-forming surface F.

[0058] Here, the intermediate film 22 of each Al-based system is made of AlN (aluminum nitride). The elemental ratio of Al to N in aluminum nitride can be any ratio as long as it remains stable.

[0059] It should be noted that the material (material) of at least one Al-based intermediate film 22 can be aluminum, aluminum alloy, or aluminum compound other than AlN, such as Al, Al2O3, AlON (aluminum oxynitride), or a combination of at least two selected from the group containing them and AlN. The elemental ratios of Al to N, Al to O, and O to N in aluminum oxynitride are the same as in aluminum nitride. In the case of multiple Al-based intermediate films 22, the material of some Al-based intermediate films 22 can be different from the material of the other Al-based intermediate films 22.

[0060] Aluminum alloys and aluminum compounds can be alloys or compounds with aluminum as the main component. Here, the main component can be a component that constitutes more than half of the other components by weight, more than half by volume, or more than half by elemental proportion. Such matters concerning the main component also appropriately apply to cases other than the manufacture of Al-based intermediate films 22.

[0061] Figure 3 This is a schematic diagram of the manufacturing method of optical product 1. Figure 3 For the sake of simplicity, the film-forming surface F is only one side.

[0062] for Figure 3 The film-forming surface F of the substrate 2 shown in (A) is as follows: Figure 3 As shown in (B), an Al-based intermediate film 22 is formed. The Al-based intermediate film 22 is directly formed on the substrate 2 by physical vapor deposition (PVD, vacuum evaporation, sputtering, etc.). It should be noted that if the Al-based intermediate film 22 is formed on both sides of the substrate 2, an optical film 4 is formed on both sides of the substrate 2.

[0063] The following describes the process of fabricating an Al-based intermediate film 22 by forming AlN using a DC sputtering film deposition apparatus.

[0064] That is, firstly, an Al-made plate-shaped target is set up, and the film-forming chamber is evacuated as a pretreatment. Then, O2 gas is supplied to the film-forming chamber at a specified flow rate (e.g., 500 ccm / min) for a specified time (e.g., 30 seconds) from a free radical source to create free radical oxygen through the application of a high-frequency voltage, thus cleaning the substrate 2. More specifically, through this irradiation with free radical oxygen, even if organic matter adheres to the substrate 2, it will be decomposed and stripped away by the free radical oxygen and the ultraviolet light generated by the plasma. This cleaning improves the adhesion of the subsequently formed film.

[0065] Then, the Al-based intermediate film 22 is sputtered under specified process conditions. Here, the Al sputtering source works in conjunction with the introduction of argon gas (Ar gas), and nitrogen gas (N2 gas) is introduced into the film formation chamber as a free radical source. It should be noted that Ar gas can also be introduced into the free radical source instead of the sputtering source, or together with the sputtering source. The Ar gas can also be a rare gas other than Ar. Such changes in the Ar gas can also be appropriately made in other film formation processes.

[0066] In addition, Al-based intermediate films 22, such as Al2O3, can also be formed by vapor deposition.

[0067] In the vapor deposition of Al-based intermediate film 22, Al particles can be heated by electron beam (EB) in a vacuum film-forming chamber.

[0068] In the vapor deposition of Al-based intermediate film 22 made of Al2O3, O2 gas can also be introduced into the film-forming chamber under vacuum, and Al particles can be heated by EB.

[0069] like Figure 3 As shown in (C), the substrate 2, i.e. the manufacturing intermediate 20, which is an Al-based intermediate film 22, is immersed in the solution SL in the tank T.

[0070] Solution SL is formed by dissolving trace amounts of SiO2 (silicon dioxide) in water (H2O); in other words, it is an aqueous solution of trace amounts of silicon dioxide.

[0071] Thus, as Figure 3 As shown in (D), the Al-based intermediate film 22 is transformed into an Al2O3 layer 12, while a SiO2 layer 14 with a fine uneven structure is formed on the side opposite to the substrate 2. That is, the Al-based intermediate film 22 becomes an Al2O3 layer 12 and a SiO2 layer 14.

[0072] More specifically, the Al-based intermediate film 22 transforms into an Al2O3 layer 12 through a reaction accompanying partial dissolution with water in solution SL, while simultaneously adsorbing trace amounts of SiO2 from solution SL on the side opposite to the substrate 2, agglomerating into a micro-uneven structure. In solution SL, the Al-based intermediate film 22 allows multiple fine micro-villi, pyramids, cones, needles, etc., formed from SiO2 to grow along the film thickness direction. It should be noted that the orientation (orientation) of the manufacturing intermediate 20 during impregnation is not limited to... Figure 3 The horizontal posture is shown. Additionally, the number of manufacturing intermediates 20 simultaneously impregnated can be multiple.

[0073] Primarily from the perspective of better forming the SiO2 layer 14, the concentration of SiO2 in the solution SL is, for example, 10 mg / L or less, and further, 2 mg / L or less.

[0074] From the perspective of obtaining a villous structure in the shortest possible time, the temperature of solution SL is 90°C. Alternatively, the temperature of solution SL can be, for example, between 80°C and 100°C, or between 90°C and 100°C. To achieve a temperature above 100°C, special treatments such as pressurizing the water are necessary, or other treatments besides water must be used, which is very laborious.

[0075] Furthermore, from the perspective of obtaining the Al2O3 layer 12 and the SiO2 layer 14 in the shortest possible time, the immersion time in solution SL is, for example, 2 seconds to 10 minutes, or 5 seconds to 5 minutes, or 15 seconds to 3 minutes. When the immersion time is too short, the Al2O3 layer 12 and the SiO2 layer 14 cannot be sufficiently obtained; when the immersion time is too long, the processing time increases, and the efficiency decreases accordingly.

[0076] After that, as Figure 3 As shown in (E), the substrate 2 with Al2O3 layer 12 and SiO2 layer 14 is taken out from tank T and dried, thus as shown in (E). Figure 3 The optical product 1 is shown in (F).

[0077] Example

[0078] Next, preferred embodiments of the present invention and comparative examples not belonging to the present invention will be described.

[0079] It should be noted that the present invention is not limited to the following embodiments. Furthermore, according to the understanding of the present invention, the following embodiments may sometimes be considered comparative examples, or the following comparative examples may sometimes be considered embodiments.

[0080] [Example 1]

[0081] Manufacturing of Example 1, etc.

[0082] Example 1 corresponds to the above-described implementation method.

[0083] In Example 1, an Al-based intermediate film 22 made of AlN was formed on both sides of a PC plate substrate 2 by DC sputtering under the process conditions shown in the top row, excluding the rows of item names in Table 1 below, with a physical film thickness of 72 nm.

[0084] Then, the manufacturing intermediate 20 was immersed in a solution SL containing 0.06 mg / L silica at 90°C for 3 minutes and dried to become Example 1 of optical product 1.

[0085] In particular, the silica concentration of solution SL is determined as follows: Specifically, the silica concentration of solution SL is measured using PACKTEST silica (low concentration), manufactured by Kyoritsu Chemical Research Institute Co., Ltd., based on the blue colorimetric principle of molybdenum blue absorption spectroscopy. This PACKTEST silica (low concentration) can measure the silica concentration in the sample within the range of 0.5–20 mg / L. When the silica concentration is below 0.5 mg / L, the solvent (H₂O) used as a solvent in solution SL separated from the sample is concentrated by heating and evaporation. The volume reduction of the concentrated solution is measured, and the silica concentration of the concentrated solution is also measured. For this measured concentration, the silica concentration of solution SL before concentration is determined by calculating the volume reduction of the solvent.

[0086] Table 1

[0087]

[0088] Characteristics of Example 1, etc.

[0089] Figure 4 It is a graph showing the single-sided reflectance of light incident perpendicularly to the film-forming surface F of the substrate 2 in Example 1 (incident angle θ = 0°) in the visible light region and the adjacent region.

[0090] Figure 5 It is a graph showing the transmittance of light in the visible light region and adjacent regions that are incident perpendicularly to the film-forming surface F of the substrate 2 in Example 1 (the ratio of the intensity of transmitted light I2 through the optical film 4 on the surface, the substrate 2, and the optical film 4 on the back to the intensity of incident light I1).

[0091] As can be seen from these graphs, in Example 1, low reflectance for visible light (e.g., less than 1% across the entire visible light region) was achieved.

[0092] Figure 6It is a graph showing the bifacial reflectance of light in the visible light region and the adjacent region (mainly the ratio of the total intensity of reflected light R1 and R2 to the intensity of incident light I1) when the incident angle θ of the film-forming surface F of the substrate 2 of Example 1 is changed in various ways.

[0093] in addition, Figure 7 This is a graph showing the dependence of the reflectance of both surfaces on the incident angle, with the horizontal axis representing the incident angle θ and the vertical axis representing the average reflectance of a specific region within the visible light area. Here, the specific region is from 420 nm to 680 nm. All average reflectance values ​​are calculated within this specific region.

[0094] As can be seen from these graphs, in Example 1, low reflectivity was achieved to the same extent as with vertical incidence up to an incident angle θ = 45° (e.g., less than 2% across the entire visible light region), and also to the extent that the average reflectivity in the visible light region was less than 2% at an incident angle θ = 50°. That is, the low reflectivity in Example 1 was achieved over a wide range of incident angles θ (characteristic of a moth's eye), and the incident angle dependence of the low reflectivity in Example 1 can be said to be low in the range of 0° to 50°.

[0095] Furthermore, the structure and composition of the optical film 4 in Example 1 were observed according to the following guidelines.

[0096] That is, an optical film 4 is fabricated on one side of a PC substrate using the same method as in Example 1, and cut into size for placement into a copper sample holder using a Ga (gallium) beam (FIB (Focused Ion Beam) processing). Furthermore, in order to place the substrate with the optical film 4 into the sample holder and preserve the structure of the optical film 4, a carbon protective film is applied to the cut substrate with the optical film 4 to create an observation object.

[0097] The object was observed using a transmission electron microscope (TEM), and elemental analysis of the optical film 4 was performed by irradiating the object with characteristic X-rays.

[0098] Figure 8 It is a graph of the spectrum of characteristic X-rays.

[0099] Depend on Figure 8 It can be seen that the observed object contains C (carbon atom), O (oxygen atom), Cu (copper), Ga (gallium), Al (aluminum atom), and Si (silicon atom).

[0100] Of these, Cu comes from the sample holder. Ga comes from the FIB process. Additionally, C comes from the protective film. Therefore, optical film 4 contains O, Al, and Si.

[0101] Figure 9 These are images observed using TEM. Figure 10 Is for Figure 9 The observation range is determined by the intensity distribution of Kα rays in C, and the image is created by showing that the concentration of a pixel increases proportionally with the intensity at the pixel's location (C-Kα ray overlay image). Figure 11 It concerns the Kα rays of O and Figure 10 The same image (overlapping image of O-Kα rays). Figure 12 It concerns the Kα rays of Al and Figure 10 The same image (Al-Kα ray superimposed image). Figure 13 It concerns the Kα rays of Si and Figure 10 The same image (overlapping Si-Kα ray image).

[0102] These figures show that a layer with a fine, uneven structure exists on the substrate (the horizontally elongated rectangular portion at the bottom of the image). Furthermore, carbon (C) is present in the portion of the substrate outside the layer and the fine uneven structure (corresponding to a protective film). O is present in both the layer and the fine uneven structure. Al is present in the layer on the substrate. Si is present in the fine uneven structure.

[0103] Furthermore, by appropriately comparing the above observations, it can be seen that the main component of the layer on the substrate is Al oxide, and the main component of the fine uneven structure is Si oxide. In addition, considering other observations such as their stability, it can be said that the main component of the layer on the substrate is Al2O3, and the main component of the fine uneven structure is SiO2.

[0104] Furthermore, if we take into account the observations of Examples 2 to 38 described below, it can be said that due to the differences in various manufacturing conditions such as the material and thickness of the Al-based intermediate film 22 and the temperature of the solution SL, the Al2O3 layer on the substrate (the layer on the substrate side) and the SiO2 layer with fine uneven structure (the uneven layer) are sometimes clearly separated as two layers, and sometimes they are not strictly separated as two layers. The composition gradually changes according to the position in the film thickness direction (the direction perpendicular to the film).

[0105] In the latter case, the boundaries of various films are sometimes unclear. Furthermore, in this case, typically, in the substrate-side layers, the closer to the substrate, the higher the Al2O3 content; the farther away from the substrate, the higher the SiO2 content relative to Al2O3. That is, in the film thickness direction, the SiO2 content relative to Al2O3 is directly proportional to the distance from the substrate.

[0106] Furthermore, the uneven layer can contain Al2O3 in a state where it is not a major component. For example, the uneven layer can have: a core (skeleton) of a fine uneven structure with Al2O3 as the main component and a capping layer with SiO2 as the main component covering part or all of the core.

[0107] [Examples 2-37 and Comparative Example 1]

[0108] Manufacturing of Examples 2-37, etc.

[0109] Examples 2-37 and Comparative Example 1 were manufactured in the same manner as Example 1. However, as shown in Tables 2-9 below, at least one of the following in Examples 2-37 and Comparative Example 1 differs from that in Example 1: silica concentration of solution SL, material of Al-based intermediate film 22, material of substrate 2, temperature of solution SL, and physical film thickness of Al-based intermediate film 22.

[0110] All Al-based intermediate films 22 in Examples 2-37 and Comparative Example 1 were formed by DC sputtering. Their process conditions varied according to the different materials of the Al-based intermediate films 22, as shown in Table 1 above. It should be noted that, as a variation, the process conditions for vapor deposition are also shown in Table 1.

[0111] Table 2

[0112] Example 1 Example 2 Example 3 Example 4 Example 5 Silica concentration (mg / L) 0.06 0.06 0.06 0.06 0.06 Al-based interlayer materials AlN AlN AlN AlN AlN Substrate material PC PC PC PC PC Solution temperature (°C) 90 95 95 95 90 Al-based intermediate film thickness (nm) 75 78.5 58.6 44.8 105.4 Average reflectance (%) 0.5 1.31 1.38 1.43

[0113] Table 3

[0114] Example 6 Example 7 Example 8 Example 9 Example 10 Silica concentration (mg / L) 0.06 0.06 0.06 0.06 0.06 Al-based interlayer materials AlN AlN AlN AlN AlN Substrate material PC PC PC PC PC Solution temperature (°C) 90 90 90 90 85 Al-based intermediate film thickness (nm) 90.85 78.5 58.5 44.8 78.51 Average reflectance (%) 0.87 0.43 1.27 1.33 0.36

[0115] Table 4

[0116] Example 11 Example 12 Example 13 Example 14 Example 15 Silica concentration (mg / L) 0.06 0.06 0.06 0.06 0.06 Al-based interlayer materials AlN AlN AlN AlN AlN Substrate material PC PC PC PC PC Solution temperature (°C) 85 85 80 80 80 Al-based intermediate film thickness (nm) 58.5 44.8 105.4 90.85 78.51 Average reflectance (%) 1.35 1.33 1.7 1.11 0.43

[0117] Table 5

[0118] Example 16 Example 17 Example 18 Example 19 Example 20 Silica concentration (mg / L) 0.06 0.06 0.06 0.06 0.06 Al-based interlayer materials AlN AlN AlN AlN AlN Substrate material PC PC PC PC PC Solution temperature (°C) 80 80 75 75 75 Al-based intermediate film thickness (nm) 58.5 44.8 78.5 58.5 44.82 Average reflectance (%) 1.7 1.33 1.87 1.94 1.33

[0119] Table 6

[0120] Example 21 Example 22 Example 23 Example 24 Example 25 Silica concentration (mg / L) 0.06 0.06 0.06 0.06 0.06 Al-based interlayer materials AlN AlN <![CDATA[Al2O3]]> <![CDATA[Al2O3]]> <![CDATA[Al2O3]]> Substrate material Whiteboard glass Whiteboard glass Whiteboard glass Whiteboard glass Whiteboard glass Solution temperature (°C) 90 90 90 98 90 Al-based intermediate film thickness (nm) 48 80 64 133 133 Average reflectance (%) 0.046 0.21 1.04 0.45 1.79

[0121] Table 7

[0122] Example 26 Example 27 Example 28 Example 29 Example 30 Silica concentration (mg / L) 0.06 0.06 0.06 0.06 0.06 Al-based interlayer materials <![CDATA[Al2O3]]> <![CDATA[Al2O3]]> <![CDATA[Al2O3]]> Al <![CDATA[Al2O3 <!-- 8 -->]]> Substrate material Whiteboard glass Whiteboard glass Whiteboard glass Whiteboard glass PC Solution temperature (°C) 95 95 90 90 90 Al-based intermediate film thickness (nm) 133 198 198 10 74 Average reflectance (%) 0.55 0.38 0.35 1.69 1.08

[0123] Table 8

[0124] Example 31 Example 32 Example 33 Example 34 Example 35 Silica concentration (mg / L) 0.06 0.003 0.06 0.5 1 Al-based interlayer materials <![CDATA[Al2O3]]> AlN AlN AlN AlN Substrate material PC PC PC PC PC Solution temperature (°C) 80 90 90 90 90 Al-based intermediate film thickness (nm) 75 78.5 78.5 78.5 78.5 Average reflectance (%) 3.82 0.27 0.41 0.5 0.75

[0125] Table 9

[0126] Example 36 Example 37 Comparative Example 1 Silica concentration (mg / L) 2 10 20 Al-based interlayer materials AlN AlN AlN Substrate material PC PC PC Solution temperature (°C) 90 90 90 Al-based intermediate film thickness (nm) 78.5 78.5 78.5 Average reflectance (%) 1.35 4.38 9.82

[0127] Characteristics of Examples 2-37 and Comparative Example 1, etc.

[0128] Figure 14These are curves showing the single-sided reflectivity of light when it is incident perpendicularly on the visible light region and adjacent regions in Examples 2-6. Figure 15 It is the same as in Examples 7-11. Figure 14 The same diagram. Figure 16 It is the same as in Examples 12-16. Figure 14 The same diagram. Figure 17 It is the same as in Examples 17-20. Figure 14 The same diagram. Figure 18 It is the same as in Examples 21-26. Figure 14 The same diagram. Figure 19 It is in Examples 27-31 and Figure 14 The same diagram. Figure 20 The examples 32-37 and Comparative Example 1 are related to... Figure 14 The same diagram.

[0129] In addition, the average reflectance is shown at the bottom of each of Tables 2 to 9.

[0130] Based on these graphs and tables, it can be seen that in Comparative Example 1, the average reflectance exceeds 9% and approaches 10%, making it difficult to say that the suppression of visible light reflection is sufficient.

[0131] In contrast, it can be seen that in Examples 2 to 37, low reflectance of visible light was achieved in the same way as in Example 1.

[0132] Furthermore, through various observations, it was confirmed that in Examples 2 to 37, low reflection was achieved in the same manner as in Example 1 with low dependence on incident angle. In addition, the micro-uneven structure was made of SiO2 (the main component of the micro-uneven structure is a layer of SiO2), and there was an Al2O3 layer (the main component of Al2O3) between the micro-uneven structure and the substrate.

[0133] In particular, when the intermediate film 22 of the Al-based manufacturing process is AlN, an anti-reflective optical film 4 is formed under various physical film thicknesses of the intermediate film 22 of the Al-based manufacturing process and the temperature of the solution SL (Examples 1 to 20).

[0134] Furthermore, even if the intermediate film 22 is made of Al2O3 (Examples 23-28, 30-31) or Al (Example 29), an anti-reflective optical film 4 is formed.

[0135] Furthermore, even if the substrate is white glass, an anti-reflective optical film 4 is formed (Examples 21-29).

[0136] "Temperature of the Solution, etc. - Examples 2, 7, 10, 15, 18"

[0137] The comparison of the above examples 2, 7, 10, 15 and 18 revealed the changes in properties of solution SL caused by temperature changes.

[0138] Examples 2, 7, 10, 15, and 18 are common in terms of silica concentration (0.06 mg / L), material of Al-based intermediate film 22 (AlN), substrate material (PC), and physical film thickness of Al-based intermediate film 22 (78.5–78.51 nm). The differences lie in the solution SL temperature, which is 95, 90, 85, 80, and 75 °C, respectively.

[0139] Figure 21 These are graphs showing the single-sided reflectivity of vertically incident light in Examples 2, 7, 10, 15, and 18.

[0140] Figure 22 The graph shows the average reflectance in Examples 2, 7, 10, 15, and 18.

[0141] As can be seen from these figures, if the temperature of solution SL is above 80°C, the single-sided reflectivity can be further reduced compared to when it is below 80°C (Example 18).

[0142] "Silica Concentration of Solutions, etc. - Examples 32-37, Comparative Example 1"

[0143] The comparison between Examples 32-37 and Comparative Example 1 revealed the changes in properties caused by the change in silica concentration in solution SL.

[0144] Examples 32-37 and Comparative Example 1 are common in the material (AlN), substrate material (PC), temperature (90°C) of solution SL, and physical film thickness (78.5 nm) of the Al-based intermediate film 22. The differences lie in the silica concentration in solution SL, which are 0.003, 0.06, 0.5, 1, 2, 10, and 20 mg / L, respectively.

[0145] The silica concentration in solution SL was adjusted by directly using highly pure water (Example 32) or water of normal purity (Example 33), or by adding an appropriate amount of silica gel to the latter and stirring thoroughly. In the former and the latter pure water, trace amounts of silica were not completely eliminated and remained.

[0146] It should be noted that the concentration of silica is determined as described in Example 1.

[0147] The above Figure 20 Examples 32-37 and Comparative Example 1 are shown here.

[0148] Figure 23The graph shows the relationship between the average reflectance (vertical axis) and the silica concentration (horizontal axis) of solution SL in Examples 32-37 and Comparative Example 1.

[0149] Table 10 shows the relationship between the silica concentration and the average reflectance of solution SL in Examples 32-37 and Comparative Example 1.

[0150] Table 10

[0151] Silica concentration (mg / L) 0.003 0.06 0.5 1 2 10 20 Average reflectance (%) of 420-680nm 0.36 0.33 0.4 0.52 0.75 3.46 15.63

[0152] As can be seen from these figures and tables, if the silica concentration of solution SL is 10 mg / L or less, a further reduction in one-sided reflectivity can be achieved compared to when it exceeds 10 mg / L (Comparative Example 1). Furthermore, if the silica concentration of solution SL is 2 mg / L or less, a further reduction in one-sided reflectivity can be achieved compared to when it exceeds 2 mg / L (Example 37, Comparative Example 1).

[0153] It should be noted that in Comparative Example 1, no change occurred in the Al-based intermediate film 22 in solution SL, and the Al-based intermediate film 22 remained as a layered AlN.

[0154] Furthermore, unlike the above-described embodiments and comparative examples, as a reference example, an Al-based intermediate film 22, identical to that in Examples 32-37 and Comparative Example 1 (excluding the silica concentration of solution SL), was immersed in tap water heated to 90°C in solution SL for 3 minutes. This reference example, like Comparative Example 1, did not exhibit a reflectivity suppression effect, and no change occurred in the Al-based intermediate film 22. The silica concentration of the tap water was 20 mg / L.

[0155] Summary, etc.

[0156] Examples 1 to 37 include a substrate 2 (substrate) and an optical film 4 formed directly on its film-forming surface F. The optical film 4 has: an Al2O3 layer 12, which is an Al2O3 layer disposed on the substrate 2 side; and a SiO2 layer 14, which is a SiO2 layer with a fine uneven structure. Alternatively, the examples include a substrate 2 (substrate) and an optical film 4 formed directly on its film-forming surface F. The optical film 4 has: an Al2O3 layer 12, which is an Al2O3 layer disposed on the substrate 2 side; and a SiO2 layer 14, which is a SiO2 layer with a fine uneven structure.

[0157] Thus, a substrate 2 (optical product 1) with an optical film 4 is provided that exhibits anti-reflective properties with low dependence on the incident angle.

[0158] The manufacturing methods of Examples 1 to 37 include: a step of forming an Al-based intermediate film 22, which is aluminum, an aluminum alloy, or an aluminum compound, on a substrate 2; and a step of immersing the substrate 2 with the Al-based intermediate film 22 in an aqueous solution of silica (solution SL), wherein the concentration of silica in solution SL is different from that in Comparative Example 1 (20 mg / L), and is 10 mg / L or less. Thus, an optical product 1 is obtained, which has an optical film 4 containing a fine, uneven structure made of SiO2 and exhibits antireflective properties under conditions of low incident angle dependence.

[0159] Furthermore, in the manufacturing methods of Examples 1-17 and 21-37, the solution SL (aqueous solution) is at a temperature of 80°C or higher and 100°C or lower. Additionally, in the manufacturing methods of Examples 1-37, the Al-based intermediate film 22 is at least one of Al, Al₂O₃, AlN, and AlON. Thus, an optical product 1 with an optical film 4 exhibiting superior anti-reflective properties can be obtained.

[0160] Symbol Explanation

[0161] 1··Optical products, 2··Substrate, 12··Al2O3 layer, 14··SiO2 layer, 22··Al-based intermediate film, F··Film-forming surface, SL··Solution (aqueous solution).

Claims

1. An optical product, characterized by, It possesses: Substrate; and An optical film, which is formed directly or indirectly on the film-forming surface of the substrate. The optical film has the following characteristics: A thin film of Al2O3, disposed on the substrate side, wherein Al2O3 comprises more than half by volume; and The SiO2 layer is a layer with a fine, uneven structure, and by volume, SiO2 accounts for more than half of the layer. The SiO2 layer has: a core of the fine, uneven structure, in which Al2O3 constitutes more than half by volume; and a covering layer, in which SiO2 constitutes more than half by volume, covering part or all of the core. The core contains Al2O3 in a manner that comprises no more than half of the SiO2 layer by volume. The average reflectance of light incident on the optical film at an incident angle of 50° is less than 2% in the wavelength region between 420nm and 680nm.

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