JP7274799B2 - optical products - Google Patents

Description

TECHNICAL FIELD The present invention relates to an optical product on which a film having fine unevenness is formed.

Patent Document 1 (Japanese Patent Application Laid-Open No. 2012-198330) discloses that a layer having a fine uneven structure of aluminum or a compound thereof is formed on the outermost surface of a base material having a curved surface by vapor phase film formation and at a temperature of 60° C. or more and boiling temperature or less. It is described to be formed by hydrothermal treatment.
The average height of the projections in the uneven structure is about 5 to 1000 nm (nanometers).
The density of such a film having a fine uneven structure (moth-eye) decreases from the substrate side toward the air side. Therefore, the refractive index of the film gradually changes. Thus, the film may act to eliminate optical interfaces or act like a low refractive index thin film. The film exhibits an antireflection effect due to their action and can be used as an antireflection film.

JP 2012-198330 A

As described above, it is known that aluminum or its compound forms a fine concave-convex structure made of aluminum or its compound.
However, the formation of fine uneven structures made of other materials, particularly silica (SiO ₂ ), is not known.

Accordingly, a main object of the present disclosure is to provide an optical product having a film with a fine uneven structure made of a material other than aluminum or a compound thereof.

In order to achieve the above object, a substrate and an optical film formed directly or indirectly on a film formation surface of the substrate are provided, and the optical film comprises Al oxide and Si oxidation. and having a thin-film Al oxide layer in which Al oxide is the majority in volume ratio, and Si having a fine uneven structure, placed on the substrate side. and a Si oxide layer that is a layer in which the oxide of Al is the majority in volume ratio, and the Si oxide layer has the fine uneven structure in which the oxide of Al is the majority in volume ratio. and a coat covering part or all of the core and having a majority volume ratio of Si oxide , and the core does not constitute a majority volume ratio in the Si oxide layer. and an optical product having an average reflectance of 2% or less in a wavelength range of 420 nm or more and 680 nm or less of light incident on the optical film at an incident angle of 50°. provided.

A main effect of the present disclosure is to provide an optical product having a film with a fine uneven structure made of a material other than aluminum or a compound thereof.

1 is a schematic cross-sectional view of an optical product according to the present invention; FIG. FIG. 2 is a schematic cross-sectional view of a production intermediate for the optical product of FIG. 1; (A) to (F) are schematic diagrams relating to a method for manufacturing the optical product of FIG. 1. FIG. 4 is a graph related to single-sided reflectance for normal incidence in Example 1. FIG. 4 is a graph relating to the transmittance of normal incidence in Example 1. FIG. 4 is a graph of double-sided reflectance of light at various angles of incidence θ for Example 1. FIG. 4 is a graph relating to incident angle dependence of double-sided reflectance in Example 1. FIG. 4 is a spectrum graph of characteristic X-rays in the same observation target as in Example 1. FIG. 9 is a TEM observation image of the observation target in FIG. 8. FIG. FIG. 9 is a C-Kα line overlapping image of the observation target in FIG. 8. FIG. 9 is an O-Kα ray overlapped image of the observation target in FIG. 8; FIG. 9 is an Al-Kα ray overlapping image of the observation target of FIG. 8. FIG. FIG. 9 is a Si-Kα ray overlapped image of the observation target of FIG. 8. FIG. 10 is a graph relating to single-sided reflectance at normal incidence in Examples 2 to 6. FIG. FIG. 14 is a view similar to FIG. 14 in Examples 7 to 11. FIG. FIG. 14 is a view similar to FIG. 14 in Examples 12 to 16. FIG. FIG. 14 is a view similar to FIG. 14 in Examples 17 to 20. FIG. FIG. 14 is a view similar to FIG. 14 in Examples 21 to 26. FIG. FIG. 14 is a view similar to FIG. 14 in Examples 27 to 31. FIG. 14 for Examples 32 to 37 and Comparative Example 1. FIG. 10 is a graph showing single-sided reflectance at normal incidence in Examples 2, 7, 10, 15, and 18 in which the temperature of the solution that is the immersion destination during manufacturing is different. 10 is a graph of average reflectance in Examples 2, 7, 10, 15 and 18. FIG. 4 is a graph showing the relationship between the average reflectance (vertical axis) and the silica concentration of the solution (horizontal axis) in Examples 32 to 37 and Comparative Example 1. FIG.

Hereinafter, examples of embodiments according to the present invention will be described with appropriate reference to the drawings.
In addition, the present invention is not limited to the following examples.

[Composition, etc.]
As shown in FIG. 1, an optical product 1 of the present invention comprises a base material 2 and an optical film 4 formed on a film formation surface F of the base material 2 . In the drawings, the thickness of the optical film 4 is exaggerated with respect to the thickness of the substrate 2 .
The optical product 1 is used as a translucent antireflection member. That is, in the optical product 1 , the optical film 4 suppresses the intensity of the reflected light R1 with respect to the intensity of the incident light I1 (incident angle θ) to the optical product 1 .
In FIG. 1, the transmitted light I2, which is the light that the incident light I1 is transmitted through the surface opposite to the incident surface, and the reflected light R2, which is the light that the incident light I1 is reflected from the surface, are combined. It is shown. Also, the optical product 1 may be used for purposes other than an antireflection member.

The base material 2 is the base on which the optical product 1 is formed, and is plate-like (substrate) here. The substrate 2 has translucency, and the transmittance of visible light, which is light having a wavelength in the visible range (here, 400 nm or more and 750 nm or less), is approximately 100%. The shape of the substrate 2 may be a flat plate shape, a curved plate shape, or a shape other than a plate shape such as a block shape.
Plastic is used as the material (material) of the base material 2, and polycarbonate resin (PC), which is a thermosetting resin, is used here. The material of the base material 2 is not limited to PC, and examples include polyurethane resin, thiourethane resin, episulfide resin, polyester resin, acrylic resin, polyethersulfone resin, poly-4-methylpentene-1 resin, and diethylene glycol bisallyl carbonate resin. , or a combination thereof. Furthermore, the material of the substrate 2 may be glass or other material other than plastic.

The film formation surface F of the substrate 2 is arranged on the front and back surfaces, and the optical film 4 is directly provided on the front and back surfaces. The optical film 4 may be provided on one of the front surface and the back surface, or may be provided on three or more surfaces of the block-shaped substrate 2 or the like. An intermediate film such as a hard coat film may be provided between at least one of the optical films 4 and the substrate 2 . When such an intermediate film is provided, the optical film 4 is indirectly formed on the substrate 2 .
The optical film 4 on the back surface has the same structure as the optical film 4 on the front surface. The optical film 4 on the front surface will be described below, and the description of the optical film 4 on the back surface will be omitted as appropriate.
The optical film 4 includes an Al ₂ O ₃ layer 12 made of alumina as the first layer and a SiO ₂ layer 14 made of silica having a fine concave-convex structure as the second layer, counting from the substrate 2 side (the same applies hereinafter). I have.
Alternatively, the optical film 4 includes an Al ₂ O ₃ layer whose main component is Al ₂ O ₃ as the first layer, and a layer whose main component is SiO ₂ having a fine uneven structure as the second layer. SiO ₂ layer 14 . In this case, the boundary between the first layer and the second layer may be unclear. Also, typically, in the first layer, the closer to the substrate 2 the higher the Al ₂ O ₃ component ratio, and the farther from the substrate 2 the greater the SiO ₂ to Al ₂ O ₃ component ratio. That is, in the film thickness direction, the component ratio of SiO ₂ to Al ₂ O ₃ in the first layer has a proportional relationship with the distance from the substrate 2 . The first layer can be regarded as a thin film layer that does not have a fine uneven structure, regardless of the material distribution. Alternatively, the first layer can be regarded as the foundation (base) of the fine uneven structure. Alternatively, the first layer can be regarded as a thin film-like layer without a fine uneven structure, and a layer in which the material gradually changes within the layer. Furthermore, the second layer may contain Al ₂ O ₃ in a state that does not form a main component. For example, the second layer has a nucleus (skeleton) with a fine uneven structure mainly composed of Al ₂ O ₃ and a coat mainly composed of SiO ₂ covering part or all of the nucleus. can. The second layer can be regarded as a layer having a fine uneven structure regardless of the material distribution.
The height of the SiO ₂ layer 14 is, for example, about 1 nm or more and 1000 nm or less (nano-size order). The fine uneven structure in the SiO ₂ layer 14 is, for example, a fluff-like structure, a pyramid group-like structure, a pin-like structure, or a combination thereof.

[Manufacturing method, etc.]
The optical product 1 is manufactured from the manufacturing intermediate 20 shown in FIG. The production intermediate 20 includes a substrate 2 and an Al-based production intermediate film 22 formed on the film formation surface F, respectively.
Each Al-based production intermediate film 22 is made of AlN (aluminum nitride) here. The element ratio of Al and N in aluminum nitride may be any as long as it exists stably.
The material of at least one of the Al-based production intermediate films 22 may be aluminum, an aluminum alloy, or an aluminum compound other than AlN, such as Al, Al ₂ O ₃ , AlON (aluminum oxynitride), or A combination of at least two selected from the group including these and AlN may also be used. The element ratio of Al and N, the element ratio of Al and O, and the element ratio of O and N in aluminum oxynitride are the same as in the case of aluminum nitride. When a plurality of Al-based production intermediate films 22 are present, the material of some of the Al-based production intermediate films 22 may be different from the material of the other Al-based production intermediate films 22 .
Aluminum alloys and aluminum compounds may be alloys or compounds containing aluminum as a main component. Here, the main component may be a component with a majority weight ratio, a majority volume ratio, or a majority element ratio with respect to other components. It can be. Matters relating to such main components also apply appropriately to materials other than the Al-based production intermediate film 22 .

FIG. 3 is a schematic diagram of the method for manufacturing the optical product 1. FIG. In FIG. 3, the film-forming surface F is only one side for the sake of simple explanation.
As shown in FIG. 3B, an Al-based production intermediate film 22 is formed on the film formation surface F of the substrate 2 shown in FIG. 3A. The Al-based production intermediate film 22 is directly formed on the substrate 2 by physical vapor deposition (PVD), vacuum deposition, sputtering, or the like. By forming the Al-based production intermediate film 22 on both surfaces of the substrate 2 , the optical films 4 are formed on both surfaces of the substrate 2 .

A case where the Al-based production intermediate film 22 made of AlN is formed by DC sputtering in a DC sputtering film forming apparatus will be described below.
That is, first, a plate-shaped target made of Al is set and the film formation chamber is evacuated, and as a pretreatment, O ₂ gas is supplied from a radical source to a predetermined flow rate in a state in which a high frequency voltage is applied and becomes radical oxygen. The cleaning of the base material 2 is performed by supplying (for example, 500 ccm (Cubic Centimeter per Minute)) to the film formation chamber for a predetermined time (for example, 30 seconds). More specifically, even if an organic substance or the like adheres to the base material 2, the organic substance or the like is decomposed and peeled off by the radical oxygen and the ultraviolet rays generated by the plasma due to the irradiation of the radical oxygen. Such cleaning improves the adhesion of the film to be formed later.
Then, the Al-based production intermediate film 22 is sputtered under predetermined process conditions. Here, the Al sputtering source is operated together with the introduction of argon gas (Ar gas), and nitrogen gas (N ₂ gas) is introduced into the deposition chamber as a radical source. Ar gas may be introduced in the radical source instead of the sputtering source or together with the sputtering source. Ar gas may be a rare gas other than Ar. Such a change related to Ar gas may also be appropriately performed in other film formation.

Also, the Al-based production intermediate film 22 made of Al ₂ O ₃ or the like may be formed by vapor deposition.
In vapor deposition of the Al-based production intermediate film 22 made of Al, Al granules may be heated by an electron beam (EB) in a film forming chamber in a vacuum state.
In the vapor deposition of the Al-based production intermediate film 22 made of Al ₂ O ₃ , O ₂ gas may be introduced into a film forming chamber in a vacuum state, and Al granules may be heated by EB.

The substrate 2 with such an Al-based production intermediate film 22, that is, the production intermediate 20 is immersed in the solution SL in the tank T as shown in FIG. 3(C).
The solution SL is a solution in which a trace amount of SiO ₂ (silica) is dissolved in water (H ₂ O), in other words, an aqueous solution of a trace amount of silica.
Then, as shown in FIG. 3(D), the Al-based production intermediate film 22 changes into an Al ₂ O ₃ layer 12, and a SiO ₂ layer 14 having a fine uneven structure on the side opposite to the substrate 2. generate That is, the Al-based production intermediate film 22 becomes the Al ₂ O ₃ layer 12 and the SiO ₂ layer 14 .
More specifically, the Al-based production intermediate film 22 converts a trace amount of SiO ₂ in the solution SL into the base material 2 while changing into the Al ₂ O ₃ layer 12 through a reaction accompanied by partial dissolution with water in the solution SL. It is gradually adsorbed on the opposite side and collected so as to have a fine concave-convex structure. In the Al-based production intermediate film 22, a large number of fine fluffs, pyramids, cones, needle-like bodies, etc. made of _SiO2 are grown in the film thickness direction in the solution SL. The posture (orientation) of the manufacturing intermediate 20 during immersion is not limited to the horizontal posture as shown in FIG. Moreover, the number of manufacturing intermediates 20 to be immersed at the same time may be plural.
The concentration of SiO ₂ in the solution SL is, for example, 10 mg/l (milligrams per liter) or less, more preferably 2 mg/l or less, mainly from the viewpoint of better formation of the SiO ₂ layer 14 .
The temperature of the solution SL is 90° C. here from the viewpoint of obtaining the fluff-like structure and the like in as short a time as possible. Also, the temperature of the solution SL is, for example, 80° C. or higher and 100° C. or lower, or 90° C. or higher and 100° C. or lower. In order to raise the temperature to 100° C. or higher, the water must be subjected to a special treatment such as pressurization, or a solution other than water must be used, which is troublesome.
Further, the immersion time in the solution SL is, for example, 2 seconds or more and 10 minutes or less, or 5 seconds or more and 5 minutes or less, from the viewpoint of obtaining the Al ₂ O ₃ layer 12 and the SiO ₂ layer 14 in as short a time as possible, Alternatively, it is 15 seconds or more and 3 minutes or less. If the immersion time is too short, the Al ₂ O ₃ layer 12 and the SiO ₂ layer 14 will not be sufficiently obtained, and if the immersion time is too long, the processing time will be longer and the efficiency will be lowered accordingly.

After that, as shown in FIG. 3(E), the substrate 2 with the Al ₂ O ₃ layer 12 and the SiO ₂ layer 14 is taken out from the bath T and dried to form the substrate shown in FIG. 3(F). Thus, the optical product 1 is completed.

Next, preferred examples of the present invention and comparative examples not belonging to the present invention will be described.
In addition, the present invention is not limited to the following examples. Moreover, depending on how the present invention is understood, the following examples may substantially become comparative examples, and the following comparative examples may substantially become working examples.

[Example 1]
≪Production of Example 1, etc.≫
Example 1 corresponds to the embodiment described above.
In Example 1, the Al-based production intermediate film 22 made of AlN was formed into a plate-shaped substrate made of PC by DC sputtering under the process conditions shown in the top row in Table 1 below, except for the row with the item names. Films were formed on both sides of the material 2 with a physical film thickness of 72 nm.
Then, the production intermediate 20 was immersed in a 90° C. solution SL containing 0.06 mg/l silica for 3 minutes and dried to obtain Example 1 of the optical product 1 .
In particular, the silica concentration of solution SL was determined as follows. That is, the silica concentration of the solution SL was measured using Pack Test Silica (low concentration) manufactured by Kyoritsu Rikagaku Kenkyusho Co., Ltd. based on the principle of blue color development in molybdenum blue absorption spectroscopy. This pack test silica (low concentration) can measure the silica concentration in the sample within the range of 0.5 to 20 mg/l. When the silica concentration is lower than 0.5 mg/l, the solvent (H ₂ O) of the solution SL taken as a sample is concentrated by heat evaporation, the volume reduction of the concentrated solution is measured, and the silica concentration of the concentrated solution is measured. The silica concentration of the solution SL of the sample before concentration was determined by calculating the volume reduction of the solvent in consideration of the measured concentration.

<<Characteristics of Example 1>>
FIG. 4 is a graph of single-sided reflectance of light in the visible region and the adjacent region that is incident perpendicularly (at an incident angle θ=0°) to the film formation surface F of the substrate 2 of Example 1. FIG.
FIG. 5 shows the transmittance of light in the visible region and the adjacent region (the optical film 4 on the front surface, the substrate 2, and the optical film 4 on the back surface) that is vertically incident on the film formation surface F of the substrate 2 of Example 1. 2 is a graph of the ratio of the intensity of the transmitted light I2 to the intensity of the incident light I1.
These graphs show that Example 1 achieves a low reflection of visible light (for example, 1% or less in the entire visible range).

FIG. 6 shows the double-sided reflectance of light in the visible region and the adjacent region (mainly the total intensity of reflected light R1 and R2 to the intensity of the incident light I1).
FIG. 7 is a graph showing the incidence angle dependence of the double-sided reflectance, with the horizontal axis representing the incident angle θ and the vertical axis representing the average of the reflectances in the specific region within the visible range (average reflectance). Here, the specific region is 420 nm or more and 680 nm or less. Hereinafter, various average reflectances are all calculated in this specific region.
According to these graphs, in Example 1, up to an incident angle θ = 45°, low reflection (for example, 2% or less in the entire visible range) is realized at the same level as normal incidence, and even at an incident angle θ = 50° It can be seen that low reflection is achieved to the extent that the average reflectance in the visible range is 2% or less. That is, the low reflection in Example 1 is realized in a wide range of incident angles θ (feature of moth-eye), and the incidence angle dependency of low reflection in Example 1 is low in the range of 0° to 50°. I can say

Furthermore, the structure and components of the optical film 4 in Example 1 were observed in the following manner.
That is, an optical film 4 was formed on one side of a PC substrate by the same manufacturing method as in Example 1, and cut to a size that would fit into a copper sample holder with a Ga (gallium) beam (FIB (Focused Ion Beam) processing). . Then, the substrate with the optical film 4 was placed in a sample holder, and in order to preserve the structure of the optical film 4, the cut substrate with the optical film 4 was covered with a protective film made of carbon to form an observation target.
This observation target was observed with a transmission electron microscope (TEM), and elemental analysis of the optical film 4 was performed by irradiating this observation target with characteristic X-rays.

FIG. 8 is a spectrum graph of characteristic X-rays.
From FIG. 8, it can be seen that the observation target contains C (carbon atom), O (oxygen atom), Cu (copper), Ga (gallium), Al (aluminum atom), and Si (silicon atom).
Of these, Cu originates from the sample holder. Also, Ga originates from the FIB processing. Furthermore, C originates from the protective film. Therefore, the optical film 4 contains O, Al and Si.

FIG. 9 is a TEM observation image. FIG. 10 is an image (C-Kα ray overlap image) in which the density of pixels is proportionally increased as the intensity at the position of the pixel increases according to the intensity distribution of the Kα ray of C with respect to the observation range of FIG. ). FIG. 11 is a diagram similar to FIG. 10 (O-Kα line overlap image) for the O Kα line. FIG. 12 is a diagram similar to FIG. 10 (Al-Kα ray overlapped image) for the Kα ray of Al. FIG. 13 is a diagram similar to FIG. 10 (Si-Kα ray overlapped image) for the Kα ray of Si.
According to these figures, it can be seen that a layer exists on the substrate (horizontally long rectangular portion occupying the bottom of the image), and a fine concave-convex structure exists on the layer. In addition, it can be seen that C exists in the substrate and the portion (corresponding to the protective film) other than the layer and the fine concave-convex structure. Furthermore, it can be seen that O exists in the layer and the fine relief structure. Furthermore, it can be seen that Al is present in the layer on the substrate. In addition, it can be seen that Si exists in the fine uneven structure.

If the above observations are properly combined, 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. Furthermore, considering other observations such as their stability, it can be said that the main component of the layer on the substrate is Al ₂ O ₃ and the fine relief structure is mainly SiO ₂ .
In addition, considering the observation results of Examples 2 to 38, etc., which will be explained below, the difference in the material and film thickness of the Al-based production intermediate film 22, the temperature of the solution SL, and other various production conditions may cause the The Al ₂ O ₃ layer (substrate-side layer) and the SiO ₂ layer with the fine uneven structure (uneven layer) may be clearly separated as two layers, and strictly speaking, they are not separated into two layers. may change gradually depending on the position in the film thickness direction (the direction perpendicular to the film).
In the latter case, the boundaries of the various membranes may be blurred. In this case, typically, in the layer on the substrate side, the component ratio of Al ₂ O ₃ is higher the closer to the substrate, and the component ratio of SiO ₂ to Al ₂ O ₃ increases as the distance from the substrate increases. That is, in the film thickness direction, the component ratio of SiO ₂ to Al ₂ O ₃ is proportional to the distance from the substrate.
Further, the uneven layer can contain Al ₂ O ₃ in a state that does not form the main component. For example, the rugged layer may have a nucleus (skeleton) of a fine rugged structure mainly composed of Al ₂ O ₃ and a coat mainly composed of SiO ₂ covering part or all of the nucleus.

[Examples 2 to 38 and Comparative Example 1]
≪Production of Examples 2 to 37, etc.≫
Examples 2-37 and Comparative Example 1 were prepared in the same manner as Example 1, respectively. However, as shown in the following Tables 2 to 9, in Examples 2 to 37 and Comparative Example 1, the silica concentration of the solution SL, the material of the Al-based production intermediate film 22, the material of the base material 2, and the content of the solution SL At least one of the temperature and the physical thickness of the Al-based production intermediate film 22 is different from that of the first embodiment.
All of the Al-based production intermediate films 22 of Examples 2 to 37 and Comparative Example 1 were formed by DC sputtering, and their process conditions were divided for each material of the Al-based production intermediate film 22, and are shown in Table 1 above. It is Table 1 also shows process conditions for vapor deposition as a modified example.

<<Characteristics of Examples 2 to 37 and Comparative Example 1>>
FIG. 14 is a graph showing single-sided reflectance at normal incidence of light in the visible range and adjacent range in Examples 2 to 6. FIG. FIG. 15 is a view similar to FIG. 14 in Examples 7-11. FIG. 16 is a view similar to FIG. 14 in Examples 12-16. FIG. 17 is a view similar to FIG. 14 in Examples 17-20. FIG. 18 is a view similar to FIG. 14 in Examples 21-26. FIG. 19 is a view similar to FIG. 14 in Examples 27-31. FIG. 18 is a diagram similar to FIG. 14 for Examples 32 to 37 and Comparative Example 1. FIG.
Also, the bottom row of each of Tables 2 to 9 shows the average reflectance of each.
According to these graphs and tables, in Comparative Example 1, the average reflectance exceeded 9% and approached 10%, and it can be seen that it is difficult to say that suppression of reflection to visible light is sufficient.
On the other hand, in Examples 2 to 37, as in Example 1, low reflection of visible light is realized.
From various observations, it was found that in Examples 2 to 37, as in Example 1, low reflection was realized with low incident angle dependence, and the fine uneven structure was made of SiO ₂ (fine uneven structure It was confirmed that _{a layer of Al 2 O 3 (mainly composed of Al 2 O 3 ) was} present between the fine uneven structure and the substrate.
In particular, when the Al-based production intermediate film 22 is AlN, the optical film 4 related to antireflection was formed at various physical film thicknesses of the Al-based production intermediate film 22 and various temperatures of the solution SL (Example 1 ~20).
Further, even when the Al-based manufacturing intermediate film 22 was Al ₂ O ₃ (Examples 23 to 28, 30 to 31) or Al (Example 29), the optical film 4 related to antireflection was formed.
Furthermore, even when the substrate was white plate glass, the optical film 4 for antireflection was formed (Examples 21 to 29).

<<Solution temperature, etc., Examples 2, 7, 10, 15, 18>>
Changes in properties due to changes in temperature of solution SL are found by comparison of Examples 2, 7, 10, 15 and 18 above.
In Examples 2, 7, 10, 15, and 18, the silica concentration (0.06 mg/l), the material (AlN) of the Al-based production intermediate film 22, the substrate material (PC), and the physical film of the Al-based production intermediate film 22 The thickness (78.5 to 78.51 nm) is common, and the temperature of the solution SL is 95, 90, 85, 80, and 75° C., respectively.

FIG. 21 is a graph of single-sided reflectance for normal incidence in Examples 2, 7, 10, 15, and 18. FIG.
FIG. 22 is a graph of average reflectance in Examples 2, 7, 10, 15, and 18. FIG.
These figures show that when the temperature of the solution SL is 80° C. or higher, the single-sided reflectance can be further reduced as compared with the case where the temperature is lower than 80° C. (Example 18).

<<Silica concentration of solution, etc., Examples 32 to 37, Comparative example 1>>
Changes in properties due to changes in the temperature of the solution SL are found by comparing Examples 32-37 and Comparative Example 1 above.
In Examples 32 to 37 and Comparative Example 1, the material (AlN) of the Al-based production intermediate film 22, the substrate material (PC), the temperature of the solution SL (90° C.), the physical thickness of the Al-based production intermediate film 22 (78 .5 nm), and the silica concentrations of the solutions SL are different from each other in the order of 0.003, 0.06, 0.5, 1, 2, 10 and 20 mg/l.
For the silica concentration of solution SL, pure water with extremely high purity (Example 32) or pure water with normal purity (Example 33) was used as it was, or an appropriate amount of silica gel was added to the latter pure water. It was adjusted by stirring well. In the former pure water and the latter pure water, a small amount of silica remains without being completely removed.
The determination of the silica concentration was made as described in the explanation of Example 1.

The aforementioned FIG. 20 just shows Examples 32 to 37 and Comparative Example 1. FIG.
23 is a graph showing the relationship between the average reflectance (vertical axis) and the silica concentration (horizontal axis) of the solution SL in Examples 32 to 37 and Comparative Example 1. FIG.
Table 10 is a table showing the relationship between the silica concentration of the solution SL and the average reflectance in Examples 32 to 37 and Comparative Example 1.

These figures and tables show that when the temperature of the solution SL is 10 mg/l or less, the single-sided reflectance is further reduced compared to when it exceeds 10 mg/l (Comparative Example 1). Further, it can be seen that when the temperature of the solution SL is 2 mg/l or less, the single-sided reflectance is further reduced compared to when it exceeds 2 mg/l (Example 37, Comparative Example 1).
In Comparative Example 1, the Al-based production intermediate film 22 did not change in the solution SL, and the Al-based production intermediate film 22 remained as layered AlN.
In addition to the above-described examples and comparative examples, as a reference example, the solution SL was tap water heated to 90 ° C. Similar to Examples 32 to 37 and Comparative Example 1 (solution SL (excluding the silica concentration of 2000) was immersed for 3 minutes. Similar to Comparative Example 1, this reference example did not exhibit the effect of suppressing the reflectance, and the Al-based production intermediate film 22 did not change. The silica concentration of this tap water was 20 mg/l.

≪Summary, etc.≫
Examples 1 to 37 include a substrate 2 (substrate) and an optical film 4 directly formed on the film formation surface F thereof. The optical film 4 is Al ₂ It has an Al ₂ O ₃ layer 12 that is a layer made of O ₃ and a SiO ₂ layer 14 that is a layer made of SiO ₂ having a fine uneven structure, or the substrate 2 (substrate) and its and an optical film 4 directly formed on the film formation surface F. The optical film 4 is an Al ₂ O ₃ layer 12 which is a layer whose main component is Al ₂ O ₃ and which is arranged on the substrate 2 side. and a SiO ₂ layer 14 having a fine uneven structure, the main component of which is SiO ₂ .
Therefore, the substrate 2 (optical product 1) with the optical film 4 exhibiting an antireflection effect with low incident angle dependence is provided.

The manufacturing methods of Examples 1 to 37 consisted of a step of forming an Al-based manufacturing intermediate film 22, which is aluminum, an aluminum alloy, or a compound of aluminum, on a substrate 2 (substrate), and a step of forming an Al-based manufacturing intermediate film 22. and a step of immersing the substrate 2 in an aqueous silica solution (solution SL), and the concentration of silica in the solution SL is 10 mg/l or less, unlike Comparative Example 1 (20 mg/l). As a result, an optical product 1 having an optical film 4 with a fine concave-convex structure made of SiO ₂ and exhibiting an antireflection effect with low incident angle dependence is obtained.
In the production methods of Examples 1 to 17 and 21 to 37, the solution SL (aqueous solution) has a temperature of 80°C or higher and 100°C or lower. Furthermore, in the manufacturing methods of Examples 1 to 37, the Al-based manufacturing intermediate film 22 is at least one of Al, Al ₂ O ₃ , AlN and AlON. Therefore, the optical product 1 having the optical film 4 exhibiting a better antireflection action can be obtained.

1 Optical product 2 Substrate 12 Al ₂ O ₃ layer 14 SiO ₂ layer 22 Al-based production intermediate film F Film-forming surface SL Solution (aqueous solution ).

Claims (1)

a substrate;
an optical film directly or indirectly formed on the film-forming surface of the substrate;
and
The optical film is
It consists of an oxide of Al and an oxide of Si ,
an Al oxide layer in the form of a thin film, which is arranged on the substrate side and is a layer in which the Al oxide is the majority in volume ratio;
a Si oxide layer, which is a layer in which Si oxide is the majority in volume ratio, and which has a fine uneven structure ;
and
The Si oxide layer comprises a nucleus of the fine uneven structure in which the Al oxide is the majority in volume ratio, and a coat in which the Si oxide partially or wholly covers the nucleus and the Si oxide is the majority in volume ratio. , and
The nucleus contains an Al oxide in a state that does not constitute a majority of the volume ratio in the Si oxide layer,
An optical product, wherein an average reflectance of light incident on the optical film at an incident angle of 50° in a wavelength range of 420 nm or more and 680 nm or less is 2% or less.

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