Water-repellent glass member, method for manufacturing the same, and cover member

Abstract

To provide a water-repellent glass component that exhibits excellent water repellency without forming a water-repellent coating on its surface. [Solution] A water-repellent glass member 1 having irregularities on its surface 1a, wherein in a 5μm × 5μm region on the irregular surface 1a, when the cutoff value of the high-pass filter λc is 2.5μm, the average length RSm1 of the elements of the roughness curve is 70nm or more and 800nm ​​or less, and in a 140μm × 105μm region on the irregular surface 1a, when the cutoff value of the low-pass filter λs is 0.80μm, the average length RSm2 of the elements of the roughness curve is 3.0μm or more and 100.0μm or less.

Description

[Technical Field]

[0001] The present invention relates to a water-repellent glass member, a method for producing the water-repellent glass member, and a lens member, a cover member, and a window panel member using the water-repellent glass member. [Background Art]

[0002] For cameras used outdoors such as in-vehicle cameras and surveillance cameras, it is required to prevent water droplets from adhering to the camera surface and obtain clear images even in rainy weather. Therefore, glass members with high water repellency are demanded as lens members and cover members for such cameras.

[0003] Furthermore, in automobiles, railway vehicles, ships, aircraft, and the like, using a window panel with high water repellency makes it possible to omit mechanisms such as wipers. This enables reduction in the number of parts and shortening of the manufacturing process, so reduction in manufacturing cost can be expected. Accordingly, in recent years, demand for glass with high water repellency has been increasing more and more.

[0004] Patent Document 1 below discloses a front lens water-repellent cleaning structure for a vehicle lamp, characterized in that the surface of the front lens is coated with a fluorine-based or silicone-based resin. [Prior Art Documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Unexamined Patent Publication No. Hei 6-330363 [Summary of the Invention] [Problem to be Solved by the Invention]

[0006] However, as described in Patent Document 1, when a coating made of an organofluorine compound or the like is formed on the surface of a glass component, an extremely thin coating is often formed, and the coating may wear off or peel off due to friction such as rubbing. Therefore, there is a problem in that it is difficult to maintain high water repellency over a long period of time.

[0007] The object of the present invention is to provide a water-repellent glass member that has excellent water repellency without forming a water-repellent coating on its surface, a method for manufacturing the water-repellent glass member, and a lens member, a cover member, and a window panel member using the water-repellent glass member. [Means for solving the problem]

[0008] Each embodiment for solving the above problems will be described.

[0009] The water-repellent glass member according to Embodiment 1 of the present invention is a water-repellent glass member having an uneven surface, characterized in that, in a 5 μm × 5 μm region on the uneven surface, when the cutoff value of the high-pass filter λc is 2.5 μm, the average length RSm1 of the elements of the roughness curve is 70 nm or more and 800 nm or less, and in a 140 μm × 105 μm region on the uneven surface, when the cutoff value of the low-pass filter λs is 0.80 μm, the average length RSm2 of the elements of the roughness curve is 3.0 μm or more and 100.0 μm or less.

[0010] In the water-repellent glass member according to embodiment 2 of the present invention, in embodiment 1, it is preferable that the arithmetic mean height Sa1 is 1 nm or more and 50 nm or less when the cutoff value of the high-pass filter λc is 2.5 μm in a 5 μm × 5 μm region on the surface having irregularities.

[0011] In the water-repellent glass member according to embodiment 3 of the present invention, in embodiment 1 or 2, it is preferable that the arithmetic mean height Sa2 is 1 nm or more and 1500 nm or less in a 140 μm × 105 μm region on the surface having irregularities, when the cutoff value of the low-pass filter λs is 0.80 μm.

[0012] In the water-repellent glass member according to embodiment 4 of the present invention, in any one embodiment of embodiments 1 to 3, it is preferable that the skewness Ssk is -0.1 or less in a 5 μm × 5 μm region on the surface having irregularities, when the cutoff value of the high-pass filter λc is 2.5 μm.

[0013] In the water-repellent glass member according to Embodiment 5 of the present invention, in any one embodiment of Embodiments 1 to 4, when the cutoff value of the high-pass filter λc is set to 2.5 μm in a 5 μm × 5 μm region on the surface having irregularities, it is preferable that the ratio of the average height Rc1 to the average length RSm1 of the elements of the roughness curve (Rc1 / RSm1) is 0.02 or more and 1.00 or less.

[0014] In the water-repellent glass member according to embodiment 6 of the present invention, it is preferable that in any one embodiment of embodiments 1 to 5, the contact angle of water with the surface having irregularities of the water-repellent glass member is 90° or more.

[0015] In any one of the embodiments of embodiments 1 to 6, the water-repellent glass member according to embodiment 7 of the present invention may comprise a glass member body and a water-repellent film provided on the main surface of the glass member body.

[0016] In any one embodiment of embodiments 1 to 7, the water-repellent glass member according to embodiment 8 of the present invention may comprise a glass member body and an optical functional film provided on the main surface of the glass member body.

[0017] In the water-repellent glass member according to aspect 9 of the present invention, in aspect 8, it is preferable that the optical functional film is an anti-reflective film or a reflective film.

[0018] A method for producing a water-repellent glass member according to the present invention is a method for producing a water-repellent glass member configured according to any one of aspects 1 to 9, characterized by comprising: a step of performing a chemical etching treatment on a surface of a glass member; and a step of performing a wet blast treatment on the surface of the glass member after performing the chemical etching treatment.

[0019] A lens member according to aspect 11 of the present invention is characterized by comprising a water-repellent glass member configured according to any one of aspects 1 to 9.

[0020] A cover member according to aspect 12 of the present invention is characterized by comprising a water-repellent glass member configured according to any one of aspects 1 to 9.

[0021] A window panel member according to aspect 13 of the present invention is characterized by comprising a water-repellent glass member configured according to any one of aspects 1 to 9.

Effects of the Invention

[0022] According to the present invention, there can be provided a water-repellent glass member having excellent water repellency without forming a water-repellent coating on the surface, a method for producing said water-repellent glass member, and a lens member, a cover member, and a window panel member using said water-repellent glass member.

Brief Description of Drawings

[0023] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a water-repellent glass member according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing a roughness curve of a relatively small region on a first main surface of the water-repellent glass member according to the first embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing a roughness curve of a relatively large region on a first main surface of the water-repellent glass member according to the first embodiment of the present invention. [Figure 4]FIG. 4 is a schematic cross-sectional view illustrating a water-repellent glass member according to a second embodiment of the present invention. [Figure 5] FIG. 5 is a photograph showing a water droplet placed on the surface of the water-repellent glass member obtained in Example 4. [Figure 6] FIG. 6 is a photograph showing a water droplet placed on the surface of the glass member obtained in Comparative Example 2. [Figure 7] FIG. 7 is a photograph showing a water droplet placed on the surface of the glass member obtained in Comparative Example 4. MODE FOR CARRYING OUT THE INVENTION

[0024] Preferred embodiments of the present invention will be described below. However, the following embodiments are merely illustrative, and the present invention is not limited to the following embodiments. In addition, in each drawing, members having substantially the same function may be referred to with the same reference numeral.

[0025] (First Embodiment) FIG. 1 is a schematic cross-sectional view illustrating a water-repellent glass member according to a first embodiment of the present invention.

[0026] As shown in FIG. 1, a water-repellent glass member 1 (hereinafter, "water-repellent glass member 1" may be simply referred to as "glass member 1") has a rectangular flat plate shape. However, the shape of the glass member 1 is not particularly limited, and may be a flat plate having a circular or polygonal outline, an entirely curved shape of a flat plate, or a spherical or aspherical lens shape, or the like.

[0027] The material of the glass member 1 is not particularly limited, and examples thereof include quartz glass, soda-lime glass, alkali-free glass, aluminosilicate glass, borosilicate glass, fluoride glass, and chalcogenide glass. One of these materials may be used alone, or two or more thereof may be used in combination.

[0028] The thickness of the glass member 1 is not particularly limited, and may be, for example, 50 μm or more and 100 mm or less.

[0029] The glass member 1 has a first main surface 1a and a second main surface 1b that are opposite to each other. The first main surface 1a and the second main surface 1b are the surfaces of the glass member 1. In this embodiment, irregularities are formed on the entire surface of the first main surface 1a of the glass member 1.

[0030] In this invention, it is sufficient that at least a portion of the first main surface 1a of the glass member 1 has irregularities. Preferably, these irregularities cover 1% or more of the first main surface 1a of the glass member 1, more preferably 30% or more, and even more preferably 50% or more. However, as in this embodiment, the irregularities may be provided over the entire surface of the first main surface 1a of the glass member 1. Furthermore, the irregularities may also be provided on the second main surface 1b of the glass member 1.

[0031] In this embodiment, in a 5 μm × 5 μm region on the first main surface 1a of the glass member 1, when the cutoff value of the high-pass filter λc is set to 2.5 μm, the average length RSm1 of the roughness curve elements is between 70 nm and 800 nm. Furthermore, in a 140 μm × 105 μm region on the first main surface 1a of the glass member 1, when the cutoff value of the low-pass filter λs is set to 0.80 μm, the average length RSm2 of the roughness curve elements is between 3.0 μm and 100.0 μm. The average length RSm of the roughness curve elements can be measured in accordance with JIS B 0601:2013.

[0032] Since the glass member 1 of this embodiment has the above configuration, it has excellent water repellency even without forming a water-repellent coating on its surface.

[0033] Conventionally, it has been known that when irregularities are formed on a solid surface, the tendency of the solid surface to wet with water differs greatly depending on whether the solid is hydrophilic or hydrophobic.

[0034] Specifically, Wenzel's model explains that in the case of hydrophilic solids, creating irregularities on the solid surface further improves hydrophilicity, while in the case of hydrophobic solids, creating irregularities on the solid surface further improves hydrophobicity.

[0035] In this case, since the surface of the glass component is hydrophilic, creating irregularities on its surface will further improve its hydrophilicity.

[0036] In response to this, the inventors focused on both the roughness curve of a relatively small area on the first main surface 1a (surface) of the glass member 1 and the roughness curve of a relatively large area on the first main surface 1a (surface) of the glass member 1. The roughness curve of a relatively small area on the first main surface 1a (surface) of the glass member 1 is represented, for example, as the roughness curve shown in Figure 2. The roughness curve of a relatively large area on the first main surface 1a (surface) of the glass member 1 is represented, for example, as the roughness curve shown in Figure 3. Note that the roughness curves in Figures 2 and 3 are schematic roughness curves shown for explanatory purposes, and the area enclosed by the dashed line in Figure 3 corresponds to the roughness curve in Figure 2.

[0037] Specifically, the inventors have discovered that by adjusting the average length RSm1 of the roughness curve elements in a relatively small area (a 5 μm × 5 μm area) on the first main surface 1a (hereinafter also referred to as the surface) of the glass member 1, and the average length RSm2 of the roughness curve elements in a relatively large area (a 140 μm × 105 μm area) on the first main surface 1a of the glass member 1, to a specific range, the water repellency of the surface of the glass member 1 can be surprisingly improved.

[0038] Furthermore, the following explanation can be given for this point. By setting the RSm1 on the surface of the glass component 1 to 70 nm or more and 800 nm or less, it is thought that air layers are retained in the depressions of the unevenness on the surface of the glass component 1, thereby reducing the wettability of the surface. In addition, by setting the RSm2 on the surface of the glass component 1 to 3.0 μm or more and 100.0 μm or less, it is thought that more air layers are retained in the depressions of the unevenness on the surface of the glass component 1, thereby further reducing the wettability of the surface. As a result of these factors, it is thought that the water repellency of the surface of the glass component 1 is enhanced.

[0039] In the present invention, the RSm1 on the surface of the glass member 1 is preferably 80 nm or more, more preferably 90 nm or more, even more preferably 100 nm or more, particularly preferably 110 nm or more, most preferably 120 nm or more, preferably 700 nm or less, more preferably 600 nm or less, even more preferably 500 nm or less, particularly preferably 400 nm or less, and most preferably 350 nm or less.

[0040] When the RSm1 on the surface of the glass member 1 is greater than or equal to the lower limit, the air layer can be more reliably retained in the recesses of the uneven surface of the glass member 1, thereby further enhancing water repellency. Conversely, when the RSm1 on the surface of the glass member 1 is less than or equal to the upper limit, it becomes more difficult for liquid to penetrate into the recesses of the uneven surface of the glass member 1, thereby further reliably retaining the air layer. This further enhances water repellency.

[0041] In the present invention, the RSm2 on the surface of the glass member 1 is preferably 3.2 μm or more, more preferably 3.4 μm or more, even more preferably 3.6 μm or more, particularly preferably 3.8 μm or more, most preferably 4.0 μm or more, preferably 90.0 μm or less, more preferably 80.0 μm or less, even more preferably 70.0 μm or less, even more preferably 60.0 μm or less, even more preferably 50.0 μm or less, even more preferably 40.0 μm or less, and even more preferably 30.0 μm or less.

[0042] When the RSm2 on the surface of the glass component 1 is greater than or equal to the lower limit, the difference with RSm1 can be made even larger, allowing more air layers to be retained in the depressions of the uneven surface of the glass component 1. This further enhances water repellency. Conversely, when the RSm2 on the surface of the glass component 1 is less than or equal to the upper limit, it becomes more difficult for liquid to penetrate into the depressions of the uneven surface of the glass component 1, allowing the air layers to be retained more reliably. This further enhances water repellency.

[0043] In the present invention, in a 5 μm × 5 μm region on the first main surface 1a of the glass member 1, when the cutoff value of the high-pass filter λc is set to 2.5 μm, the arithmetic mean height Sa1 is preferably 1 nm or more, more preferably 2 nm or more, even more preferably 3 nm or more, even more preferably 4 nm or more, even more preferably 5 nm or more, preferably 50 nm or less, more preferably 40 nm or less, even more preferably 30 nm or less, particularly preferably 20 nm or less, and most preferably 15 nm or less. The arithmetic mean height Sa(Sa1) can be measured in accordance with ISO 25178.

[0044] When the arithmetic mean height Sa1 on the surface of the glass member 1 is greater than or equal to the lower limit, it becomes more difficult for liquid to penetrate into the depressions of the uneven surface of the glass member 1, and the air layer can be held more reliably. This further enhances water repellency. Furthermore, when the arithmetic mean height Sa1 on the surface of the glass member 1 is less than or equal to the upper limit, it becomes more difficult for light scattering due to the uneven shape to occur, and the transparency of the surface of the glass member 1 is less likely to be impaired. From the viewpoint of further enhancing water repellency, in a 5 μm × 5 μm region on the first main surface 1a of the glass member 1, when the cutoff value of the high-pass filter λc is set to 2.5 μm, the arithmetic mean height Sa1 may be, for example, 10 nm or more, 15 nm or more, 20 nm or more, 25 nm or more, 30 nm or more, 31 nm or more, 33 nm or more, 35 nm or more, 38 nm or more, 40 nm or more, 43 nm or more, or 45 nm or more.

[0045] Therefore, by keeping the arithmetic mean height Sa1 on the surface of the glass member 1 within the above range, the water repellency on the surface of the glass member 1 can be further improved, and the transparency of the surface of the glass member 1 can be made less susceptible to damage.

[0046] In the present invention, in a 140 μm × 105 μm region on the first main surface 1a of the glass member 1, when the cutoff value of the low-pass filter λs is set to 0.80 μm, the arithmetic mean height Sa2 is preferably 1 nm or more, more preferably 3 nm or more, even more preferably 5 nm or more, particularly preferably 7 nm or more, most preferably 10 nm or more, preferably 1500 nm or less, more preferably 1200 nm or less, even more preferably 1000 nm or less, even more preferably 800 nm or less, even more preferably 600 nm or less, even more preferably 500 nm or less, even more preferably 400 nm or less, even more preferably 300 nm or less, particularly preferably 200 nm or less, and most preferably 100 nm or less. The arithmetic mean height Sa(Sa2) can be measured in accordance with ISO 25178.

[0047] When the arithmetic mean height Sa2 on the surface of the glass component 1 is greater than or equal to the lower limit, it becomes more difficult for liquid to penetrate into the depressions of the uneven surface of the glass component 1, and the air layer can be held more reliably. This further enhances water repellency. Conversely, when the arithmetic mean height Sa2 on the surface of the glass component 1 is less than or equal to the upper limit, it becomes more difficult for light scattering due to the uneven shape to occur, and the transparency of the surface of the glass component 1 is less likely to be impaired.

[0048] Therefore, by keeping the arithmetic mean height Sa2 on the surface of the glass member 1 within the above range, the water repellency on the surface of the glass member 1 can be further improved, and the transparency of the surface of the glass member 1 can be made less susceptible to damage.

[0049] In the present invention, when the cutoff value of the high-pass filter λc is set to 2.5 μm in a 5 μm × 5 μm region on the first main surface 1a of the glass member 1, the skewness Ssk is preferably -0.1 or less, more preferably -0.2 or less, and even more preferably -0.3 or less. The skewness Ssk can be measured in accordance with ISO 25178.

[0050] When the skewness Ssk on the surface of the glass component 1 is below the above upper limit, the histogram of the height of the uneven surface is biased upwards, the recesses are deeper than the convex parts, and the uneven surface becomes even sharper. As a result, the air layer held in the recesses is less likely to be pushed out by the liquid, making it easier to retain the air layer, thereby further improving the water repellency of the surface of the glass component 1.

[0051] The lower limit of the skewness Ssk on the first main surface 1a of the glass member 1 is not particularly limited, but can be, for example, -10.0.

[0052] In the present invention, when the cutoff value of the high-pass filter λc is set to 2.5 μm in a 5 μm × 5 μm region on the first main surface 1a of the glass member 1, the ratio of the average height Rc1 to the average length RSm1 of the elements of the roughness curve (Rc1 / RSm1) is preferably 0.02 or more, more preferably 0.03 or more, even more preferably 0.04 or more, particularly preferably 0.05 or more, most preferably 0.07 or more, preferably 1.00 or less, more preferably 0.70 or less, even more preferably 0.50 or less, particularly preferably 0.30 or less, and most preferably 0.20 or less. The ratio of the average height Rc1 to the average length RSm1 of the elements of the roughness curve (Rc1 / RSm1) can be measured in accordance with JIS B 0601:2013.

[0053] When the above ratio (Rc1 / RSm1) on the surface of the glass component 1 is greater than or equal to the lower limit, it becomes more difficult for liquid to penetrate into the depressions of the uneven surface of the glass component 1, and the air layer can be held more reliably. This further enhances water repellency. Furthermore, when the above ratio (Rc1 / RSm1) on the surface of the glass component 1 is less than or equal to the upper limit, light scattering due to the uneven shape becomes less likely, and the transparency of the surface of the glass component 1 is less likely to be impaired. In addition, damage due to abrasion, etc., can be made less likely to occur on the surface of the glass component 1, and the durability of the uneven surface can be further improved.

[0054] Therefore, by setting the ratio (Rc1 / RSm1) on the first main surface 1a of the glass member 1 within the above range, the water repellency on the surface of the glass member 1 can be further improved, and the transparency of the glass member surface can be made less likely to be impaired. In addition, damage due to abrasion and the like can be made less likely to occur on the surface of the glass member 1, and the durability of the uneven surface can be further improved.

[0055] Thus, the irregularities formed on the surface of the glass member 1 are represented by various roughness curve parameters specified by JIS B 0601:2013 (average element length RSm, ratio of average element height Rc to average element length RSm (Rc / RSm)) and various surface roughness parameters specified by ISO 25178 (arithmetic mean height Sa, skewness Ssk).

[0056] However, in the present invention, it is sufficient that at least RSm1 is between 70 nm and 800 nm, and RSm2 is between 3.0 μm and 100.0 μm, and it is not necessary to satisfy other parameters (arithmetic mean height Sa1, arithmetic mean height Sa2, skewness Ssk, ratio of average element height Rc1 to average element length RSm1 (Rc1 / RSm1)).

[0057] In this specification, "hydrophobic" means that the contact angle, which is the angle between the tangent to the liquid surface and the solid surface on the side containing the liquid, is 90° or greater.

[0058] Specifically, the water contact angle with the surface of the glass member 1 is 90° or more, preferably 93° or more, more preferably 95° or more, even more preferably 97° or more, and particularly preferably 100° or more. In this case, the water repellency on the surface of the glass member 1 can be further improved. The upper limit of the water contact angle with the surface of the glass member 1 is not particularly limited and can be, for example, 180°.

[0059] The contact angle (θ) on the surface of the glass member 1 can be measured based on the static drop method (θ / 2 approximation method) of JIS R 3257:1999. For example, in this embodiment, the glass member 1 is placed horizontally with its first main surface 1a facing upwards, 2 μL of pure water is dropped onto it, and the contact angle can be measured by photographing the water droplet from the side using a digital scope (Keyence Corporation, product name "VHX-500F").

[0060] In the present invention, the haze of the glass member 1 can be selected arbitrarily depending on the desired properties and purpose. For example, if transparency is to be more reliably ensured, the haze of the glass member 1 is preferably less than 90%, more preferably 80% or less, even more preferably 70% or less, even more preferably 60% or less, even more preferably 50% or less, even more preferably 40% or less, even more preferably 30% or less, and even more preferably 20% or less. On the other hand, from the viewpoint of more reliably suppressing reflections, the haze of the glass member 1 is preferably 3% or more, more preferably 5% or more, even more preferably 10% or more, even more preferably 15% or more, even more preferably 20% or more, even more preferably 25% or more, even more preferably 30% or more, and even more preferably 35% or more.

[0061] Because the glass member 1 of this embodiment has excellent water repellency, it can be suitably used as a lens member or cover member for cameras used outdoors, such as in-vehicle cameras and surveillance cameras. Furthermore, the glass member 1 of this embodiment can also be suitably used as a window panel member for automobiles, railway vehicles, ships, and aircraft.

[0062] (Manufacturing method) Next, an example of a manufacturing method for the glass component 1 will be described.

[0063] The irregularities on the first main surface 1a of the glass member 1 are formed by applying a chemical etching treatment to the surface of the glass member, followed by a wet blasting treatment.

[0064] Chemical etching is a process that creates irregularities by immersing a glass component in a chemical solution such as hydrofluoric acid. However, before immersing in the chemical solution, the glass component may be pre-etched with irregularities that serve as the starting point for etching, such as by wet blasting.

[0065] Wet blasting is a process in which abrasive particles, composed of solid particles such as alumina, are uniformly mixed with a liquid such as water to form a slurry, which is then sprayed at high speed from a nozzle using compressed air onto a workpiece made of glass material, thereby creating fine irregularities on the workpiece.

[0066] In wet blasting, when a high-speed ejected slurry collides with a workpiece, the abrasive particles in the slurry scrape, strike, and rub against the surface of the workpiece, creating fine irregularities on the workpiece surface.

[0067] In this case, the abrasive particles sprayed onto the workpiece, as well as the fragments of the workpiece removed by the abrasive particles, are washed away by the liquid sprayed onto the workpiece, resulting in fewer particles remaining on the workpiece.

[0068] The RSm2 and Sa2 on the surface of the resulting glass member 1 can be adjusted by chemical etching. The RSm2 and Sa2 on the surface of the glass member 1 can also be adjusted by the average particle size of the abrasive grains during the wet blasting process, which mainly creates irregularities that serve as the starting point for etching, the air pressure when spraying the slurry containing the abrasive grains, the scanning speed of the nozzle during the wet blasting process, the chemical composition of the chemical etching solution, and the processing time.

[0069] In the wet blasting process that creates irregularities that serve as the starting point for etching (hereinafter referred to as the first wet blasting process), the average particle size of the abrasive grains can be, for example, 0.2 μm or more and 60 μm or less. The average particle size of the abrasive grains can be measured, for example, by the electrical resistance method.

[0070] In the first wet blasting treatment, the air pressure used when spraying the slurry containing abrasive particles is preferably, for example, 0.1 MPa or more and 0.5 MPa or less.

[0071] In the first wet blasting process, the scanning speed of the wet blasting nozzle is preferably, for example, 0.1 mm / s or more and 100 mm / s or less.

[0072] In chemical etching, the chemical solution composition can be, for example, hydrofluoric acid, a mixed solution containing hydrofluoric acid, a mixed solution containing hydrofluoric acid and sulfuric acid, a mixed solution containing hydrofluoric acid and nitric acid, or a mixed solution containing hydrofluoric acid and hydrochloric acid. Furthermore, chelating agents such as citric acid or ethylenediaminetetraacetic acid may be added.

[0073] In chemical etching, the processing time is preferably, for example, 1 second or more and 3 hours or less.

[0074] Furthermore, the RSm1, Sa1, Ssk, and ratio (Rc1 / RSm1) on the surface of the obtained glass member 1 can be adjusted by a wet blasting treatment after chemical etching (hereinafter referred to as the second wet blasting treatment). The RSm1, Sa1, Ssk, and ratio (Rc1 / RSm1) on the surface of the glass member 1 can be adjusted by the average particle size of the abrasive grains during the second wet blasting treatment, the air pressure when spraying the slurry containing the abrasive grains, and the scanning speed of the nozzle during the second wet blasting treatment.

[0075] In the second wet blasting treatment, the average particle size of the abrasive grains is preferably, for example, 0.2 μm or more and 60 μm or less.

[0076] In the second wet blasting process, the air pressure used when spraying the slurry containing abrasive particles is preferably, for example, 0.1 MPa or more and 0.5 MPa or less.

[0077] In the second wet blasting process, the scanning speed of the wet blasting nozzle is preferably, for example, 0.1 mm / s or more and 100 mm / s or less.

[0078] In wet blasting, when slurry is sprayed onto the workpiece, the liquid carries the abrasive particles to the workpiece. This makes it easier to use finer abrasive particles compared to dry sandblasting, and also reduces the impact when the abrasive particles collide with the workpiece, enabling precise machining.

[0079] In this way, by applying chemical etching and wet blasting treatments to the workpiece (glass component), an appropriately sized uneven surface can be formed on the surface of the glass component 1. This makes it possible to improve the water repellency of the surface of the glass component 1 without impairing its transparency.

[0080] (Second embodiment) Figure 4 is a schematic cross-sectional view showing a water-repellent glass member according to a second embodiment of the present invention. As shown in Figure 4, the water-repellent glass member 21 (hereinafter, "water-repellent glass member 21" may be simply referred to as "glass member 21") comprises a glass member body 22 and a functional film 23. The functional film 23 is provided on the main surface 22a of the glass member body 22.

[0081] In this embodiment, the main surface 21a of the glass member 21 (the main surface of the functional film 23) has the same irregularities as the main surface 1a of the glass member 1 in the first embodiment. Thus, when forming the functional film 23 on the main surface 22a of the glass member body 22, the irregularities should be formed on the main surface 22a of the glass member body 22 in advance so that the irregularities of the main surface (main surface 21a) of the functional film 23 after formation are the same as the irregularities of the main surface 1a of the glass member 1 in the first embodiment. Alternatively, the irregularities may be formed after the functional film 23 has been formed.

[0082] As the functional film 23, for example, a water-repellent film can be used. As the water-repellent film, an organic thin film for improving water repellency can be used. As the organic thin film, a silane compound containing alkyl groups or fluoroalkyl groups can be used. Specifically, the organic thin film can be formed (film-formed) by bonding a silane compound containing alkyl groups or fluoroalkyl groups to the surface of a glass member.

[0083] Furthermore, the functional film 23 may be an optical functional film. As an optical functional film, for example, an anti-reflective film or a reflective film can be used. As the anti-reflective film and reflective film, a low refractive index film with a refractive index lower than that of the glass member body 22, or a dielectric multilayer film in which a low refractive index film with a relatively low refractive index and a high refractive index film with a relatively high refractive index are alternately laminated can be used. The anti-reflective film and reflective film can be formed by sputtering or CVD.

[0084] Other aspects are the same as in the first embodiment.

[0085] In the glass member 21, in a 5 μm × 5 μm region on the main surface 21a of the glass member 21, when the cutoff value of the high-pass filter λc is set to 2.5 μm, the average length RSm1 of the elements of the roughness curve is between 70 nm and 800 nm. Also, in a 140 μm × 105 μm region on the main surface 21a of the glass member 21, when the cutoff value of the low-pass filter λs is set to 0.80 μm, the average length RSm2 of the elements of the roughness curve is between 3.0 μm and 100.0 μm.

[0086] Since the glass member 21 of this embodiment has the above configuration, it has excellent water repellency even without forming a water-repellent coating on its surface.

[0087] The thickness of the functional film 23 is not particularly limited, as long as it does not hinder the effects of the present invention described above, and can be, for example, 1 nm or more and 50 μm or less.

[0088] The present invention will be described in more detail below based on specific examples. The present invention is not limited in any way to the following examples, and can be implemented with appropriate modifications without changing its essence.

[0089] (Examples 1-26) First, we prepared aluminosilicate glass (manufactured by Nippon Electric Glass Co., Ltd., product name "T2X-1") with a thickness of 0.5 mm and a rectangular plate shape.

[0090] In Examples 1 to 26, first, the entire main surface of one side of the prepared aluminosilicate glass (hereinafter also simply referred to as glass) was subjected to a wet blasting treatment (first wet blasting treatment) to create irregularities that would serve as starting points for chemical etching, and then chemical etching was performed. Next, a water-repellent glass component was fabricated by subjecting the chemically etched glass to a wet blasting treatment (second wet blasting treatment).

[0091] Specifically, in the first wet blasting treatment, a slurry was first prepared by uniformly stirring abrasive particles made of alumina with average particle sizes of 1.2 μm, 3.0 μm, 6.9 μm, 14.7 μm, or 41.1 μm with water. Next, a wet blasting treatment was performed on the entire main surface of one side of each glass, scanning the surface while moving the nozzle at a processing speed of 5 mm / s to 50 mm / s, with a processing air pressure of 0.10 MPa to 0.32 MPa, by spraying the prepared slurry from the nozzle.

[0092] In the chemical etching process, an etching solution was prepared with hydrofluoric acid at a concentration of 2% to 5% by mass, sulfuric acid at 0% to 50% by mass, and water at 48% to 98% by mass. The glass was immersed in this solution at a temperature of 30°C for 30 seconds to 30 minutes (0.5 minutes to 30.0 minutes) to perform the chemical etching.

[0093] In the second wet blasting process, a slurry was first prepared by uniformly stirring abrasive particles made of alumina with an average particle size of 1.2 μm or 4.0 μm with water. Next, the prepared slurry was sprayed onto the entire main surface on one side of each glass piece using a wet blasting process. The slurry was sprayed by scanning the nozzle while moving it at a processing speed of 10 mm / s, and by spraying the prepared slurry from the nozzle at a processing air pressure of 0.1 MPa to 0.3 MPa. In this way, glass components with uneven surfaces were fabricated.

[0094] The manufacturing conditions for the glass components in Examples 1 to 26 are shown in Tables 1 and 2 below.

[0095] [Table 1]

[0096] [Table 2]

[0097] (Comparative Example 1) In Comparative Example 1, the same aluminosilicate glass as in Example 1 was used without any of the treatments applied.

[0098] (Comparative Example 2) In Comparative Example 2, chemical etching was performed in the same manner as in Example 4, but the second wet blasting treatment was omitted. In all other respects, the glass member was obtained in the same manner as in Example 4.

[0099] (Comparative Example 3) In Comparative Example 3, chemical etching was performed in the same manner as in Example 5, but the second wet blasting treatment was omitted. In all other respects, the glass member was obtained in the same manner as in Example 5.

[0100] (Comparative Example 4) In Comparative Example 4, a glass component was fabricated by applying a wet blast treatment to the entire main surface on one side of the same glass as in Example 1. Therefore, chemical etching was not performed in Comparative Example 4.

[0101] In the wet blasting process, a slurry was first prepared by uniformly stirring abrasive particles made of alumina with an average particle size of 1.2 μm with water. Next, the prepared slurry was sprayed onto the entire main surface on one side of the glass. The slurry was sprayed by scanning the nozzle while moving it at a processing speed of 10 mm / s, with a processing air pressure of 0.2 MPa.

[0102] (Comparative Example 5) In Comparative Example 5, a glass component was fabricated by applying a wet blast treatment to the entire main surface on one side of the same glass as in Example 1. Therefore, chemical etching was not performed in Comparative Example 5.

[0103] In the wet blasting process, a slurry was first prepared by uniformly stirring alumina abrasive grains with an average particle size of 1.2 μm with water. Next, the prepared slurry was sprayed onto the entire main surface on one side of the glass. The slurry was sprayed by scanning a 1 mm diameter round nozzle at 500 μm intervals at a processing speed of 10 mm / s, with a processing air pressure of 0.2 MPa. This resulted in the creation of a surface with an RSm2 of 500.0 μm.

[0104] (evaluation) [Measurement of contact angle θ] Figure 5 is a photograph of the water droplet placed on the surface of the water-repellent glass member obtained in Example 4. Figure 6 is a photograph of the water droplet placed on the surface of the glass member obtained in Comparative Example 2, and Figure 7 is a photograph of the water droplet placed on the surface of the glass member obtained in Comparative Example 4.

[0105] As shown in Figure 5, the water-repellent glass member obtained in Example 4 exhibits high water repellency (contact angle θ: 100°). On the other hand, as shown in Figures 6 and 7, the glass members obtained in Comparative Examples 2 and 4 did not exhibit sufficient water repellency (contact angle θ of Comparative Example 2: 47°, contact angle θ of Comparative Example 4: 80°).

[0106] Next, the water contact angle θ with the surface of the water-repellent glass members of Examples 1 to 26 and the glass members of Comparative Examples 1 to 5 was measured.

[0107] The contact angle θ was measured based on the static drop method (θ / 2 approximation method) of JIS R 3257:1999. Specifically, 2 μL of pure water was dropped onto each glass component, which was placed horizontally with the main surface where the irregularities were formed facing upwards. The water droplet was then photographed from directly to the side using a digital scope (Keyence Corporation, product name "VHX-500F"), and the contact angle θ was measured.

[0108] [Surface roughness measurement] Next, the surface roughness parameters (average element lengths RSm1 and RSm2, arithmetic mean heights Sa1 and Sa2, ratio of average element height Rc1 to average element length RSm1 (Rc1 / RSm1), and skewness Ssk) were measured on the main surfaces of the glass members of Examples 1 to 26 and Comparative Examples 1 to 5. The surface roughness parameters were measured on each main surface where irregularities were formed. These measurements were performed using an atomic force microscope (AFM) or a white light interference microscope.

[0109] Furthermore, as an atomic force microscope (AFM), an atomic force microscope (manufactured by Bruker, product name: Dimension Icon (SPM unit), Nano Scope V (Controller unit)) was used, and measurements were performed in accordance with JIS B 0601:2013 and ISO 25178.

[0110] Furthermore, the measurement conditions were as follows: tapping mode was used, and the scan rate was set to 1 Hz for a measurement area of ​​5 μm × 5 μm, resulting in 512 × 512 acquired data points. The cutoff value of the high-pass filter λc was set to 2.5 μm, and the analysis was performed.

[0111] Furthermore, the white light interference microscope used for the measurements was a white light interference microscope (Zygo, model number "New View 7300"), and measurements were performed in accordance with JIS B 0601:2013 and ISO 25178. For Examples 1-26 and Comparative Examples 1-5, the measurement conditions were as follows: a 50x objective lens and a 1x zoom lens were used, and the measurement area was 140 μm × 10⁵ μm, with 10 integrations. After removing the plane tilt using the least squares method, the cutoff value of the low-pass filter λs was set to 0.80 μm, and the analysis was performed. For Comparative Example 5, the measurement conditions were as follows: a 50x objective lens and a 1x zoom lens were used, and the measurement area was shifted while measuring, until the final measurement area was 1000 μm × 720 μm.

[0112] [Haze measurement] Next, the haze of the glass components of Examples 1 to 26 and Comparative Examples 1 to 5 was measured. The haze was measured using a UV-670 ultraviolet-visible-near-infrared spectrophotometer manufactured by Shimadzu Corporation, in accordance with JIS K7361-1-1997.

[0113] The results are shown in Tables 3 and 4 below.

[0114] [Table 3]

[0115] [Table 4]

[0116] As shown in Tables 3 and 4, the glass members of Examples 1 to 26 had contact angles of 95° to 111°, confirming their excellent water-repellent properties.

[0117] On the other hand, the glass components of Comparative Examples 1 to 5 showed poor results, with contact angles ranging from 14° to 80°, indicating hydrophilicity.

[0118] Furthermore, the RSm1 values ​​for Examples 1-26 were within the range of 143.3 nm to 374.9 nm. It was also confirmed that RSm1 tended to increase as the air pressure of the second wet blasting treatment increased.

[0119] The RSm2 values ​​for Examples 1-26 were within the range of 4.1 μm to 51.4 μm. It was also confirmed that RSm2 tended to increase with increasing average particle size of abrasive grains in the first wet blasting treatment and with increasing air pressure. Furthermore, RSm2 tended to increase with increasing etching time.

[0120] On the other hand, the RSm1 of untreated Comparative Example 1 was 60.0 nm and the RSm2 was 2.5 μm. Therefore, the RSm1 and RSm2 of untreated Comparative Example 1 were both smaller than those of Examples 1 to 26.

[0121] Furthermore, the RSm1 values ​​for Comparative Examples 2 and 3, which underwent only chemical etching, ranged from 65.9 nm to 68.6 nm. The RSm2 values ​​for Comparative Examples 2 and 3 ranged from 9.7 μm to 25.2 μm. Therefore, the RSm1 values ​​for Comparative Examples 2 and 3 were smaller than those for Examples 1 to 26.

[0122] Furthermore, in Comparative Example 4, which underwent only wet blasting, the RSm1 was 189.8 nm and the RSm2 was 2.9 μm. Therefore, in Comparative Example 4, the RSm2 was smaller than that of the example. In Comparative Example 5, the RSm1 was 217.1 nm and the RSm2 was 500.0 μm. Therefore, in Comparative Example 5, the RSm2 was larger than that of the example.

[0123] The Sa1 values ​​for Examples 1-26 were in the range of 3.6 nm to 35.1 nm. It was confirmed that Sa1 tended to increase as the air pressure and average particle size of the abrasive grains increased during the second wet blasting treatment.

[0124] On the other hand, in Comparative Example 1 (untreated) and Comparative Examples 2 and 3 (treated only with chemical etching), the Sa1 values ​​were 0.1 nm to 0.4 nm, which are smaller than those of the examples.

[0125] The Sa2 values ​​for Examples 1-26 were in the range of 13.8 nm to 1075.9 nm. It was confirmed that Sa2 tended to decrease as the average particle size and processing air pressure of the first wet blasting treatment decreased, the etching treatment time increased, and the sulfuric acid concentration of the etching solution increased.

[0126] On the other hand, the untreated Comparative Example 1 showed a smaller Sa2 value of 0.1 nm compared to the example.

[0127] The Ssk values ​​for Examples 1-26 were in the range of -0.2 to -1.6.

[0128] On the other hand, Comparative Example 1 (untreated) and Comparative Examples 2 and 3 (treated only with chemical etching) had an Ssk of 0.0.

[0129] The Rc1 / RSm1 values ​​for Examples 1-26 were within the range of 0.07-0.18.

[0130] On the other hand, Comparative Example 1 (untreated) and Comparative Examples 2 and 3 (treated only with chemical etching) had a Rc1 / RSm1 of 0.01, which was a smaller value compared to the examples.

[0131] From the above, it was confirmed that the water repellency of the glass component can be improved by controlling the parameters related to the surface roughness curve of the glass component.

[0132] In particular, in Examples 1 to 26, where the average length RSm1 of the roughness curve elements was between 70 nm and 800 nm, and the average length RSm2 of the roughness curve elements was between 3.0 μm and 100.0 μm, it was confirmed that the water repellency of the surface was enhanced.

[0133] As shown in Tables 3 and 4, the haze tended to increase as Sa2 increased. It is believed that by controlling Sa2, it is possible to obtain glass components with haze suitable for the desired characteristics and purpose. [Explanation of symbols]

[0134] 1.21...Water-repellent glass components 1a, 1b…First and second main surfaces 21a, 22a...main surface 22...Glass component body 23… Functional membrane

Claims

1. A water-repellent glass member having an uneven surface, In a 5 μm × 5 μm region of the surface having the aforementioned irregularities, when the cutoff value of the high-pass filter λc is set to 2.5 μm, the average length RSm1 of the elements of the roughness curve is 70 nm or more and 800 nm or less. A water-repellent glass member wherein, in a 140 μm × 105 μm region on the surface having irregularities, when the cutoff value of the low-pass filter λs is set to 0.80 μm, the average length RSm2 of the elements of the roughness curve is 3.0 μm or more and 100.0 μm or less.

2. The water-repellent glass member according to claim 1, wherein in a 5 μm × 5 μm region on the surface having irregularities, when the cutoff value of the high-pass filter λc is 2.5 μm, the arithmetic mean height Sa1 is 1 nm or more and 50 nm or less.

3. The water-repellent glass member according to claim 1 or 2, wherein the water contact angle with the surface having irregularities of the water-repellent glass member is 90° or more.

4. The water-repellent glass member according to claim 1 or 2, wherein the average length RSm1 is 70 nm or more and 600 nm or less.

5. The water-repellent glass member according to claim 1 or 2, wherein the average length RSm2 is 3.0 μm or more and 40.0 μm or less.

6. A method for manufacturing a water-repellent glass member according to claim 1 or 2, The process involves applying a chemical etching treatment to the surface of the glass component, The process involves applying a wet blast treatment to the surface of the glass member after performing the aforementioned chemical etching treatment, A method for manufacturing a water-repellent glass component, comprising the features described above.

7. A cover member comprising the water-repellent glass member according to claim 1 or 2.

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