Mechanically simple component and method for manufacturing a mechanically simple component

Abstract

The present application provides an inorganic member and a manufacturing method of the inorganic member, which can form a micro concavo-convex on the surface of the inorganic member by a simple method, and by controlling the shape of the concavo-convex, can realize low wettability to water with excellent durability without forming (film forming) an organic fluorine-based coating film. At least a part of the main surface (1a, surface) has a micro concavo-convex (2), and the skewness Ssk of the micro concavo-convex (2) is -0.1 or less. In addition, the above-mentioned micro concavo-convex (2) is formed by performing a wet sand blasting treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to a non-mechanical member and a manufacturing method of a non-mechanical member. BACKGROUND

[0002] For example, in a motor vehicle, a railway vehicle, a ship, an aircraft, and the like, by realizing a window panel having a lower wettability to water (i.e., difficult to wet), it is possible to omit a wiper or the like, and by reducing the number of components and shortening the manufacturing process, and the like, a reduction in manufacturing cost is expected, and thus, as the member of the window panel, a non-mechanical member having a lower wettability to water has been increasingly desired in recent years.

[0003] In addition, in a non-mechanical member for an ophthalmic lens, a lens for a photographic device, research for realizing a non-mechanical member having a lower wettability to water has also been progressing compared to the past.

[0004] In addition, as a method of controlling the wettability of the surface of a certain solid, for example, a method of making the surface energy of the surface of the solid variable by forming a coating film or the like on the surface of the solid or forming a concave-convex on the surface of the solid is generally performed.

[0005] Here, in the case where a concave-convex is formed on the surface of a solid, depending on which one of hydrophilicity or hydrophobicity the property of the solid is, the tendency of the wettability to water of the surface greatly differs.

[0006] That is, it is proven by Wenzel's model that, in the case of a hydrophilic solid, by forming a concave-convex on the surface of the solid, the hydrophilicity is further improved, and the wettability to water of the surface is further improved (i.e., easy to wet), and on the other hand, in the case of a hydrophobic solid, by forming a concave-convex on the surface of the solid, the hydrophobicity is further improved, and the wettability to water of the surface is further reduced (i.e., difficult to wet).

[0007] Thus, when the surface of a non-mechanical member is hydrophilic, and a concave-convex is formed on the surface thereof, the hydrophilicity is further improved, and the wettability to water of the surface is further improved (easy to wet).

[0008] Therefore, as a technique for realizing a surface of a non-mechanical member having a lower wettability to water (difficult to wet), for example, a technique of forming (depositing) a coating film composed of an organic fluorine compound or the like on the surface of the non-mechanical member is disclosed in Patent Literature 1.

[0009] However, such a coating film formed (deposited) on the surface of a non-mechanical member is extremely thin in thickness, and the coating film is easily worn or peeled off due to friction such as scratching, and thus, it is difficult to maintain a low wettability to water for a long period of time.

[0010] Therefore, as a technique for realizing a surface of an inorganic member that is less wettable (difficult to wet) with water by forming minute irregularities instead of forming (depositing) a coating film as described above, a technique for forming irregularities of a nano-pillar structure composed of a high aspect ratio on the surface of an inorganic member is disclosed, for example, in Patent Literature 2.

[0011] Prior Art Documents

[0012] Patent Literature

[0013] Patent Literature 1: Japanese Patent Application Laid-Open (kokai) No. 6-330363

[0014] Patent Literature 2: International Publication No. 2020 / 045668 SUMMARY

[0015] PROBLEMS TO BE SOLVED BY THE INVENTION

[0016] However, even the nano-pillar structure composed of a high aspect ratio in Patent Literature 2 described above can be damaged by friction such as scratching, and it is difficult to maintain low wettability with water.

[0017] In addition, in order to form such a complex and minute nano-pillar structure, a plurality of processes are required, and the manufacturing process becomes complex, which is a factor of an increase in manufacturing cost.

[0018] The present invention has been made in view of the above-described problems, and provides an inorganic member and a manufacturing method of an inorganic member, which can form minute irregularities on the surface of an inorganic member by a simple method, and by controlling the shape of the irregularities, can realize low wettability with water that is excellent in durability without forming (depositing) a coating film of an organic fluorine-based material.

[0019] SOLUTION TO THE PROBLEM

[0020] The problem to be solved by the present invention is as described above, and next, a solution to the problem will be described.

[0021] That is, the inorganic member of the present invention is characterized in that the inorganic member has minute irregularities on at least a part of the surface, and the skewness Ssk of the minute irregularities is -0.1 or less.

[0022] If the inorganic member composed of such a structure, the minute irregularities formed on the surface are high in rigidity and excellent in durability, and can be formed simply by shot blasting or the like, for example.

[0023] In addition, compared with a smooth plane that does not have minute irregularities, the contact angle of a water droplet adhering to the surface of the inorganic member can be increased, and lower wettability with water can be realized.

[0024] Further, the non-mechanical member of the present application is preferably composed of glass.

[0025] With this structure, a non-mechanical member having high light transmittance and excellent workability can be obtained.

[0026] Further, the non-mechanical member of the present application is preferably such that, in the fine irregularities, the average length RSm of the roughness curve elements is 30 nm or more and 750 nm or less.

[0027] With this structure, the formation of fine irregularities on the surface of the non-mechanical member can be made easier, and the contact angle of a water droplet adhering to the surface of the non-mechanical member can be prevented from decreasing.

[0028] Further, the non-mechanical member of the present application is preferably such that, in the fine irregularities, the ratio (Rc / RSm) of the average height Rc of the roughness curve elements to the average length RSm of the roughness curve elements is 0.02 or more and 1.00 or less.

[0029] With this structure, the durability of the fine irregularities formed on the surface of the non-mechanical member can be improved, and the contact angle of a water droplet adhering to the surface can be prevented from decreasing for a long period of time.

[0030] Further, the non-mechanical member of the present application is preferably such that, in the fine irregularities, the arithmetic average height Sa is 1 nm or more and 100 nm or less.

[0031] With this structure, compared with a smooth flat surface having no fine irregularities, the contact angle of a water droplet adhering to the surface of the non-mechanical member can be more reliably increased, and a lower wettability to water can be achieved.

[0032] Further, the scattering of light caused by the irregularity shape of the fine irregularities can be suppressed to a minimum, and the transparency of the surface of the non-mechanical member formed with the fine irregularities can be more reliably ensured.

[0033] Further, the non-mechanical member of the present application is preferably such that, in the fine irregularities, the maximum height Sz is 30 nm or more and 500 nm or less.

[0034] With this structure, compared with a smooth flat surface having no fine irregularities, the contact angle of a water droplet adhering to the surface of the non-mechanical member can be further reliably increased, and a lower wettability to water can be achieved.

[0035] Further, the scattering of light caused by the irregularity shape of the fine irregularities can be further reliably suppressed to a minimum, and the transparency of the surface of the non-mechanical member formed with the fine irregularities can be more reliably ensured.

[0036] Further, the non-mechanical member of the present application can be characterized in that the non-mechanical member has a minute unevenness on at least a part of the surface, and a ratio (Rc / RSm) of an average height Rc of a roughness curve element to an average length RSm of the roughness curve element of the minute unevenness is 0.03 or more and 1.00 or less.

[0037] If the non-mechanical member is configured by such a structure, at least durability of the minute unevenness formed on the surface of the non-mechanical member is improved, and a decrease in a contact angle of a water droplet adhered to the surface is prevented for a long time.

[0038] Further, the manufacturing method of the non-mechanical member of the present application is a method of manufacturing any one of the above non-mechanical members, and is characterized in that a wet blasting treatment is performed on at least a part of the surface of the non-mechanical member, thereby forming the minute unevenness.

[0039] According to the manufacturing method configured by such a structure, the non-mechanical member in which the minute unevenness is formed on the surface and a contact angle of a water droplet adhered to the surface is increased compared to a smooth plane not having the minute unevenness, and lower wettability to water is achieved, can be obtained.

[0040] Effects of the Invention

[0041] As an effect of the present application, the following effects are exerted.

[0042] That is, according to the non-mechanical member and the manufacturing method of the non-mechanical member of the present application, the minute unevenness can be formed on the surface of the non-mechanical member by a simple method, and by controlling the shape of the unevenness, lower wettability to water with excellent durability can be achieved without forming (coating) an organic fluorine-based coating film. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a side sectional view showing a structure of a non-mechanical member of an embodiment of the present application.

[0044] Figure 2 is a graph for explaining various parameters indicating surface roughness in the minute unevenness formed on the non-mechanical member, Figure 2 (a) of is a graph for explaining skewness Ssk, Figure 2 (b) of is a graph for explaining an average height Rc of a roughness curve element and an average length RSm of the roughness curve element, Figure 2 (c) of is a graph for explaining an arithmetic average height Sa and a maximum height Sz.

[0045] Figure 3 is an enlarged side sectional view schematically showing a state in which a water droplet is adhered to the minute unevenness formed on the non-mechanical member. DETAILED DESCRIPTION

[0046] Next, using Figures 1 to 3 Embodiments of the non-mechanical member and the manufacturing method of the non-mechanical member of the present application will be described.

[0047] [Structure of Non-Mechanical Member 1]

[0048] First, using Figures 1 to 3 The structure of the non-mechanical member 1 of the present embodiment will be described.

[0049] The non-mechanical member 1 is composed of, for example, a rectangular flat plate-shaped member, and is mainly composed of glass, ceramic, metal, or the like.

[0050] In the case where the non-mechanical member 1 is composed of glass, as the material of the glass member, soda lime glass, alkali-free glass, alumino-silicate glass, borosilicate glass, quartz glass, and chalcogenide glass, or the like can be given.

[0051] In addition, in the case where the non-mechanical member 1 is composed of ceramic, as the material of the ceramic member, sapphire, spinel, or the like can be given.

[0052] Further, in the case where the non-mechanical member 1 is composed of metal, as the material of the metal member, germanium, silicon, or the like can be given.

[0053] Note that the non-mechanical member 1 is preferably composed of glass in terms of high light transmittance and excellent workability.

[0054] In addition, regarding the shape of the non-mechanical member 1, it is not limited to the present embodiment, and can be, for example, any one of a flat plate shape composed of a circular or polygonal outline, a shape obtained by bending the entire flat plate-shaped member, a spherical surface, a lens shape of an aspherical surface, or the like.

[0055] Further, the non-mechanical member 1 is preferably light-transmissive in at least a part of the wavelength region from the ultraviolet region to the infrared region.

[0056] As shown in FIG. 1, in the non-mechanical member 1, a minute concavo-convex 2 is formed on one surface (main surface la in the present embodiment). Figure 1 The minute concavo-convex 2 is mainly imparted to the surface of the non-mechanical member 1 with the purpose of reducing the wettability of the non-mechanical member 1 with respect to water (i.e., making it difficult to wet).

[0057] Thus, the minute concavo-convex 2 can be formed in at least a part of the region of the main surface la where low wettability with respect to water is required, according to the use state of the final non-mechanical member 1, and in the present embodiment, is formed on the entire surface of the main surface la.

[0058]

[0059] ​The minute unevenness 2 formed on the main surface la of the inorganic member 1 is constituted by a shape set by various surface parameters (skewness Ssk, average length RSm of a roughness curve element, ratio (Rc / RSm) of average height Rc of a roughness curve element to average length RSm of a roughness curve element, arithmetic average height Sa, and maximum height Sz) shown below.

[0060] That is, the minute unevenness 2 is set so that the skewness Ssk is -0.1 or less (Ssk≤-0.1), the average length RSm of a roughness curve element is 30 nm or more and 750 nm or less (30 nm≤RSm≤750 nm), the ratio (Rc / RSm) of the average height Rc of a roughness curve element to the average length RSm of a roughness curve element is 0.02 or more and 1.00 or less (0.02≤(Rc / RSm)≤1.00), the arithmetic average height Sa is 1 nm or more and 100 nm or less (1 nm≤Sa≤100 nm), and the maximum height Sz is 30 nm or more and 500 nm or less (30 nm≤Sz≤500 nm).

[0061] Note that, regarding the structure of the minute unevenness 2, at least the skewness Ssk can be outside the above set range, while the other parameters, that is, the average length RSm of a roughness curve element, the ratio (Rc / RSm) of the average height Rc of a roughness curve element to the average length RSm of a roughness curve element, the arithmetic average height Sa, and / or the maximum height Sz can be within the above set range.

[0062] Alternatively, regarding the structure of the minute unevenness 2, at least the ratio (Rc / RSm) of the average height Rc of a roughness curve element to the average length RSm of a roughness curve element can be within the above set range, while the other parameters, that is, the skewness Ssk, the average length RSm of a roughness curve element, the arithmetic average height Sa, and / or the maximum height Sz can be outside the above set range.

[0063] The "skewness Ssk" is a parameter prescribed by ISO 25178, and indicates the symmetry of the peak and valley of the unevenness shape constituting the main surface la of the inorganic member 1 when the center of the average plane (double dotted line in (a) of FIG. 1) is taken as the center. Figure 2

[0064] Specifically, as shown in (a) of FIG. 1, in the case where the skewness Ssk is a negative value (Ssk<0), the histogram of the height distribution of the minute unevenness 2 constituting the surface becomes a shape deviated to the upper side with respect to the average plane. Figure 2

[0065] ​​On the other hand, in a case where the skewness Ssk is a positive value (Ssk > 0), a histogram of the height distribution of the minute unevenness 2 constituting the surface becomes a shape that is biased to the lower side with respect to the average plane.

[0066] Further, in a case where the skewness Ssk is 0 (strictly speaking, a value close to 0) (Ssk = 0), a histogram of the height distribution of the minute unevenness 2 constituting the surface becomes a shape that is symmetrically distributed with respect to the average plane.

[0067] In the present embodiment, as described above, the structure in which the skewness Ssk of the minute unevenness 2 is -0.1 or less is imparted (refer to Figure 3 ) to the main surface la of the inorganic member 1, and a plurality of valley portions Ya, Ya,... that are narrower than the peak portions Xa, Xa,... are respectively provided between the plurality of peak portions Xa, Xa,...

[0068] As a result, as shown in Figure 3 , in a case where the water droplet W is attached to the main surface la of the inorganic member 1, the air layer Q, Q,... is easily generated in the plurality of recess portions 21, 21,... blocked by the water droplet W, the contact angle Θ of the water droplet W increases, and the wettability of the main surface la of the inorganic member 1 with respect to water becomes lower (that is, it is difficult to wet).

[0069] Note that, in the present embodiment, the upper limit value of the skewness Ssk is set to -0.1, but it is preferably -0.2, and more preferably -0.3.

[0070] Further, the lower limit value of the skewness Ssk is not particularly limited, but is limited by a technical factor of the method of forming the minute unevenness 2 (for example, the wet blasting process described later) and thus is virtually -10 or more, but is preferably -5 or more, more preferably -3 or more, further preferably -2 or more, and particularly preferably -1.5 or more.

[0071] The "average length RSm of roughness curve elements" is a parameter specified by JIS B0601:2013, and represents the average distance between the recess portions and the protrusion portions adjacent to each other in the uneven shape constituting the roughness curve 2a.

[0072] Specifically, as shown in (b) of Figure 2 , the roughness curve 2a is formed of a plurality of continuous profile curves 2a1, 2a1,..., and each profile curve 2a1 is constituted of the peak portions Xb and the valley portions Yb adjacent to each other.

[0073] It should be noted that the aforementioned peak Xb and valley Yb each have multiple fine bumps and depressions, but these fine bumps and depressions are considered noise and identified as part of the peak Xb or valley Yb if they do not meet the specified threshold (e.g., 10% of the highest height (or highest depth) of the peak Xb (or valley Yb).

[0074] Furthermore, the average length RSm of the roughness curve element is represented by the average length of the above multiple profile curves 2a1, 2a1... (RSm=(RSm1+RSm2+…RSmn) / n).

[0075] In this embodiment, as described above, the average length RSm of the roughness curve element of the micro-bumps 2 is 30 nm or more and 750 nm or less.

[0076] Here, the smaller the average length RSm of the roughness curve element, the denser the undulation shape of the micro-undulations 2 formed on the main surface 1a of the non-mechanical component 1, which is therefore preferred. However, due to the technical limitations of the method of forming the micro-undulations 2 (e.g., wet sandblasting treatment described later), it is essentially limited to the aforementioned lower limit value of 30 nm.

[0077] It should be noted that, in this embodiment, the lower limit of the average length RSm of the roughness curve element is set to 30 nm, but preferably 60 nm, more preferably 90 nm, even more preferably 120 nm, and particularly preferably 150 nm.

[0078] In addition, in this embodiment, the upper limit of the average length RSm of the roughness curve element is set to 750 nm, but preferably 700 nm, more preferably 600 nm, even more preferably 500 nm, and particularly preferably 400 nm.

[0079] It should be noted that when the average length RSm of the roughness curve elements exceeds the upper limit of 750 nm, liquid can easily penetrate the recess 21 of the micro-unevenness 2 (refer to...). Figure 3 )Inside.

[0080] As a result, in Figure 3 In the case where water droplets W are attached to the main surface 1a of the non-mechanical component 1, it is difficult to maintain an air layer Q, Q... within the multiple recesses 21, 21... blocked by the water droplets W. The contact angle θ of the water droplets W decreases, and the wettability of the main surface 1a of the non-mechanical component 1 to water becomes higher (i.e., it is easy to wet), so it is not preferred.

[0081] The ratio of the average height Rc of the roughness curve element to the average length RSm of the roughness curve element (Rc / RSm) refers to the imaginary aspect ratio of the minute bumps.

[0082] In addition, the "average height Rc of the roughness curve element" described above is a parameter prescribed by JIS B0601:2013, and indicates the average separation distance of the lower end of the concave portion and the upper end of the convex portion adjacent to each other in the concave-convex shape constituting the roughness curve 2a.

[0083] Specifically, as indicated in (b) of FIG. 6, the average height Rc of the element is indicated by the average value of the separation distance of the lower end PI of the valley portion Yb and the upper end P2 of the peak portion Xb in each of the profile curves 2a1 described above (Rc = (Rcl + Rc2 +... Rcn) / n). Figure 2

[0084] In the present embodiment, as described above, the ratio (Rc / RSm) of the average height Rc of the roughness curve element of the micro concave-convex 2 to the average length RSm of the roughness curve element is 0.02 or more and 1.00 or less.

[0085] Here, the larger the value of the ratio (Rc / RSm) described above is, the more preferable it is, and in the present embodiment, the lower limit value thereof is set to 0.02, but it is preferably 0.03, more preferably 0.05, further preferably 0.07, and particularly preferably 0.09.

[0086] In the case where the value of the ratio (Rc / RSm) described above does not satisfy the lower limit value, that is, 0.02, the liquid easily intrudes into the concave portion 21 of the micro concave-convex 2 (refer to FIG. 2). Figure 3

[0087] As a result, as in the case where the average length RSm of the element described above exceeds the upper limit value, that is, 750 nm, the wettability of the main surface la of the inorganic member 1 with respect to water becomes higher (that is, easy to wet), and thus it is not preferable.

[0088] On the other hand, in the case where the value of the ratio (Rc / RSm) described above exceeds the upper limit value, that is, 1.00, scattering of light due to the concave-convex shape of the micro concave-convex 2 easily occurs, not only the transparency of the main surface la of the inorganic member 1 is impaired, but also the inorganic member 1 is easily damaged by abrasion or the like, and the durability of the micro concave-convex 2 is reduced, and thus it is not preferable.

[0089] Note that, in the present embodiment, the upper limit value of the value of the ratio (Rc / RSm) described above is set to 1.00, but it is preferably 0.50, more preferably 0.30, further preferably 0.20, and particularly preferably 0.18.

[0090] The "arithmetic average height Sa" is a parameter prescribed by ISO 25178, and is a parameter obtained by expanding the element of the roughness curve 2a as a line into a surface.

[0091] Specifically, as indicated in (b) of FIG. 6, the average height Rc of the element is indicated by the average value of the separation distance of the lower end PI of the valley portion Yb and the upper end P2 of the peak portion Xb in each of the profile curves 2a1 described above (Rc = (Rcl + Rc2 +... Rcn) / n). Figure 2 ​​As shown in (c), the arithmetic mean height Sa represents the average of the absolute values ​​of the separation distances (e.g., the height Xh to the apex of the peak Xc and the depth Yh to the apex of the valley Yc) of each point of the concave-convex shape constituting the minute concave-convex 2 relative to the average surface Z of the main surface 1a of the unmechanical component 1 (Sa = ((Xh1 + Xh2 + ... + Xhn) + (-1)(Yh1 + Yh2 + ... + Yhn)) / 2n).

[0092] Here, in Figure 3 When the arithmetic mean height Sa is too small, it is difficult to maintain an air layer Q, Q... in the multiple recesses 21, 21... blocked by the water droplet W when the main surface 1a of the unmechanical component 1 is covered with water droplets W. The contact angle θ of the water droplet W decreases, and the wettability of the main surface 1a of the unmechanical component 1 to water becomes higher (i.e., it is easy to wet), so it is not preferred.

[0093] On the other hand, when the arithmetic mean height Sa is too large, light scattering is easily generated by the uneven shape of the tiny bumps 2, which impairs the transparency of the main surface 1a of the unstructured component 1, and is therefore not preferred.

[0094] Therefore, in this embodiment, as described above, the arithmetic mean height Sa of the micro-bumps 2 is 1 nm or more and 100 nm or less.

[0095] It should be noted that the lower limit of the arithmetic mean height Sa is set to 1 nm, but preferably 2 nm, more preferably 3 nm, even more preferably 4 nm, and particularly preferably 5 nm.

[0096] Furthermore, the upper limit of the arithmetic mean height Sa is set to 100 nm, but preferably 80 nm, more preferably 60 nm, even more preferably 40 nm, and particularly preferably 30 nm.

[0097] The “maximum height Sz” is the same as the arithmetic mean height Sa mentioned above. It is a parameter specified by ISO 25178 and is obtained by expanding the roughness curve 2a, which is a line, into a surface.

[0098] Specifically, such as Figure 2 As shown in (c), the maximum height Sz represents the sum of the absolute values ​​of the maximum separation distances of each point of the concave-convex shape constituting the minute concave-convex shape relative to the average surface Z of the main surface 1a of the unstructured component 1 (e.g., the height Xh(MAX) to the vertex of the maximum peak Xc(MAX) and the depth Yh(MAX) to the vertex of the valley Yc(MAX)) (Sz = (Xh(MAX) + (-1)(Yh(MAX))).

[0099] Here, in Figure 3When the value of the maximum height Sz is too small, in the case where the water droplets W are attached to the main surface 1a of the inorganic member 1, it is difficult to maintain the air layers Q, Q... in the plurality of recesses 21, 21... blocked by the water droplets W, the contact angle Θ of the water droplets W decreases, the wettability of the main surface 1a of the inorganic member 1 to water becomes higher (i.e., easy to wet), and thus is not preferable.

[0100] On the other hand, when the value of the maximum height Sz is too large, light scattering due to the unevenness of the minute unevenness 2 easily occurs, not only the transparency of the main surface 1a of the inorganic member 1 is impaired, but also the inorganic member 1 is easily damaged by abrasion or the like, and the durability of the minute unevenness 2 is reduced, and thus is not preferable.

[0101] Thus, in the present embodiment, as described above, the maximum height Sz in the minute unevenness 2 is 30 nm or more and 500 nm or less.

[0102] Note that, regarding the lower limit value of the maximum height Sz, 30 nm is set, but 40 nm is preferable, 50 nm is more preferable, 80 nm is further preferable, and 110 nm is particularly preferable.

[0103] In addition, regarding the upper limit value of the maximum height Sz, 500 nm is set, but 450 nm is preferable, 400 nm is more preferable, 350 nm is further preferable, and 330 nm is particularly preferable.

[0104] In addition, the contact angle Θ of the main surface 1a of the inorganic member 1 on which the minute unevenness 2 is formed is preferably 60° or more, more preferably 70° or more, further preferably 75° or more, and particularly preferably 80° or more.

[0105] Note that, the upper limit value of the contact angle Θ is not particularly limited, and for example, 180° can be set.

[0106] A hydrophobic film that reduces the surface energy of the main surface 1a can be formed (deposited) on the main surface 1a of the inorganic member 1 on which the minute unevenness 2 composed of the above-described shape is formed, for the purpose of further reducing the wettability to water (i.e., difficult to wet).

[0107] The above-described hydrophobic film can be formed (deposited) by combining a silane compound containing an alkyl group, a fluoroalkyl group, or the like with the surface (main surface 1a) of the inorganic member 1.

[0108] Note that in the case where the hydrophobic film is formed (deposited) on the main surface 1a of the inorganic member 1, a minute unevenness (minute unevenness composed of a shape similar to the above-described minute unevenness 2) is formed in advance on the main surface 1a in such a manner that the unevenness shape of the surface of the formed hydrophobic film becomes the shape set by the above-described various parameters (skewness Ssk, average length RSm of roughness curve elements, ratio (Rc / RSm) of average height Rc of roughness curve elements to average length RSm of roughness curve elements, arithmetic average height Sa, and maximum height Sz).

[0109] An antireflection film, a reflection film, a semi-reflection film, or the like can also be provided on the inorganic member 1.

[0110] The antireflection film, for example, uses a low-refractive-index film having a refractive index lower than that of the glass substrate, a dielectric multilayer film obtained by alternately stacking a low-refractive-index layer having a relatively low refractive index and a high-refractive-index layer having a relatively high refractive index.

[0111] The reflection film, the semi-reflection film, for example, uses a dielectric multilayer film obtained by alternately stacking a low-refractive-index layer having a relatively low refractive index and a high-refractive-index layer having a relatively high refractive index.

[0112] The antireflection film, the reflection film, the semi-reflection film, for example, can be formed by a sputtering method, a CVD method, or the like.

[0113] [Manufacturing method of inorganic member 1]

[0114] Next, the manufacturing method of the inorganic member 1 will be described using Figure 1

[0115] The minute unevenness 2 formed on at least a part of the surface (main surface 1a) of the inorganic member 1 is formed by performing wet sandblasting treatment or the like on the main surface 1a.

[0116] The wet sandblasting treatment is a treatment in which a material obtained by uniformly stirring abrasive grains composed of alumina or the like and a liquid such as water and making a slurry is jetted at high speed from a jetting nozzle toward a workpiece composed of the inorganic member 1, thereby forming a fine unevenness on the workpiece.

[0117] In the wet sandblasting treatment, the abrasive grains in the slurry perform grinding, striking, and scratching on the surface of the workpiece when the slurry jetted at high speed collides with the workpiece, thereby forming a fine unevenness on the surface of the workpiece.

[0118] In this case, the liquid jetted to the workpiece washes away the abrasive grains jetted to the workpiece and the fragments of the workpiece ground by the abrasive grains, and thus the particles remaining on the workpiece are reduced.

[0119] ​The surface roughness (skewness Ssk, average length RSm of roughness curve elements, ratio of average height Rc of roughness curve elements to average length RSm (Rc / RSm), arithmetic average height Sa, and maximum height Sz) of the minute unevenness 2 formed on the main surface la of the workpiece (non-member workpiece 1) by the wet blasting treatment can be adjusted mainly by the particle size distribution of the abrasive grains contained in the slurry, the blasting pressure at the time of blasting the slurry to the workpiece, and the processing speed in the movement of the nozzle.

[0120] In the wet blasting treatment, since the liquid carries the abrasive grains to the workpiece in the case of blasting the slurry to the workpiece, finer abrasive grains can be used compared to the dry blasting treatment, and the impact at the time of collision of the abrasive grains with the workpiece is small, and precise processing can be performed.

[0121] Thus, by performing the wet blasting treatment on the workpiece (non-member workpiece 1), it is easy to form a proper size of unevenness shape on the main surface la of the non-member workpiece 1, and it is possible to increase the contact angle Θ of the water droplet W attached to the main surface la of the non-member workpiece 1 without impairing the transparency of the non-member workpiece 1, and to make the wettability of the main surface la of the non-member workpiece 1 to water lower (i.e., difficult to wet).

[0122] Note that, in the dry blasting treatment, processing heat is generated in the workpiece due to friction at the time of collision of the blasted abrasive grains with the workpiece, but in the wet blasting treatment, the liquid always cools the surface of the workpiece during the treatment, and thus the workpiece is not heated by the blasting treatment.

[0123] In addition, it is also possible to form the minute unevenness 2 on the main surface la of the non-member workpiece 1 by performing the dry blasting treatment, but in the dry blasting treatment, the impact at the time of collision of the abrasive grains with the main surface la of the non-member workpiece 1 is too large, the surface roughness of the main surface la formed with the minute unevenness 2 is likely to become large, and the transparency of the non-member workpiece 1 is likely to be impaired.

[0124] In addition, in order to form the minute unevenness 2 on the main surface la of the non-member workpiece 1, in addition to the wet blasting treatment, chemical etching treatment, sol-gel method, nanoimprint method, or the like can be used.

[0125] Here, the chemical etching treatment is a treatment of chemically etching the main surface la of the non-member workpiece 1 using hydrogen fluoride (HF) gas, hydrofluoric acid, an acid such as sulfuric acid, an aqueous alkali solution such as sodium hydroxide, or the like.

[0126] Example

[0127] Next, the non-member workpiece having the minute unevenness according to the present application will be described in detail using examples and comparative examples.

[0128] Note that the structure of the non-member workpiece according to the present application is not limited to the examples shown below.

[0129] [Production of samples]

[0130] First, as examples of the non-mechanical member of the present application, samples 1 to 14 and 20 to 22 were produced, respectively, and as comparative examples with respect to these examples, samples 15 to 19 were produced, respectively.

[0131] Note that, as the material of these samples 1, 2, 7 to 15, 18 to 20, an alkali-free glass (manufactured by Nippon Electric Glass Co., Ltd., product name: OA-10G) constituted in a rectangular plate shape with a thickness of 0.5 mm was used as "glass 1".

[0132] In addition, as the material of samples 3, 4, 16, 21, 22, an aluminosilicate glass (manufactured by Nippon Electric Glass Co., Ltd., product name: T2X-1) constituted in a rectangular plate shape with a thickness of 0.5 mm was used as "glass 2".

[0133] Further, as the material of samples 5, 6, 17, a borosilicate glass (manufactured by Nippon Electric Glass Co., Ltd., product name: BDA) constituted in a rectangular plate shape with a thickness of 0.5 mm was used as "glass 3".

[0134] A wet sandblasting treatment was performed on the non-mechanical members of samples 1 to 14, 20 to 22, which are examples, to form minute irregularities on one main surface.

[0135] Specifically, a wet sandblasting was performed in which abrasive grains constituted of alumina (AI2O3) and water were uniformly stirred to prepare a slurry, a nozzle was moved relative to the entire one main surface of each non-mechanical member while scanning, and the prepared slurry was sprayed from the nozzle using air at a prescribed treatment pressure.

[0136] Here, polygonal abrasive grains of #8000 were used for the non-mechanical members of samples 1 to 12, 20, polygonal abrasive grains of #4000 were used for the non-mechanical members of samples 13, 14, 21, and polygonal abrasive grains of #2000 were used for the non-mechanical member of sample 22.

[0137] In addition, as the treatment pressure of the air of the nozzle, 0.22 MPa was set for the non-mechanical members of samples 1 to 6, 0.15 MPa was set for the non-mechanical members of samples 7, 8, 0.13 MPa was set for the non-mechanical members of samples 9 to 12, 0.10 MPa was set for the non-mechanical member of sample 13, 0.20 MPa was set for the non-mechanical member of sample 14, 0.30 MPa was set for the non-mechanical member of sample 20, and 0.25 MPa was set for the non-mechanical members of samples 21, 22.

[0138] Moreover, the above-mentioned processing speed in the movement of the nozzle was set to 10 mm / s for the non-structural member of samples 1, 3, 5, 7, 10, and 20, 5 mm / s for the non-structural member of samples 2, 4, 6, 8, 11, 13, 14, 21, and 22, 20 mm / s for the non-structural member of sample 9, and 1 mm / s for the non-structural member of sample 12.

[0139] For the non-structural member of samples 15 to 17, which were comparative examples, no processing was performed on one of the main surfaces.

[0140] That is, the non-structural member of samples 15 to 17 was not processed using an abrasive.

[0141] For the non-structural member of sample 18, which was a comparative example, a fine unevenness was formed on one of the main surfaces by performing a wet etching process based on hydrofluoric acid.

[0142] Specifically, one of the main surfaces of the non-structural member was immersed in a hydrofluoric acid solution adjusted to a concentration of 5 wt% (30°C) for a period of 2000 seconds, thereby forming the fine unevenness.

[0143] For the non-structural member of sample 19, which was a comparative example, a fine unevenness was formed on one of the main surfaces by performing a silicon coating using a sol-gel method.

[0144] Specifically, a liquid containing a silicon component was sprayed to perform coating, and the coated liquid containing the silicon component was dried, thereby forming the fine unevenness composed of a silicon coating film on the main surface.

[0145] The conditions of the material of the non-structural member of samples 1 to 19 shown above, the method of forming the fine unevenness when forming the fine unevenness, and the abrasive (abrasive grain) when performing the wet sandblasting process, the processing air pressure, and the processing speed are described in Table 1.

[0146] [Table 1]

[0147]

[0148] [Measurement of contact angle θ]

[0149] Next, in order to confirm the wettability of the non-structural members of samples 1 to 22 with respect to water, the contact angle θ of each of the main surfaces on which the fine unevenness was formed was measured.

[0150] As a method for measuring the contact angle θ, a sessile drop method (so-called θ / 2 approximation method) based on JIS R 3257:1999 was implemented, and after approximately 2 μL of pure water was dropped on each inorganic member placed horizontally in a state in which the main surface on which the minute concavo-convex was formed was directed upward, the water drop was photographed from the front side using a digital microscope (manufactured by Keyence Corporation, product name VHX-500F), and the contact angle θ was measured.

[0151] Specifically, as shown in FIG. 6, based on the image data of the photographed water drop W, the angle (θ / 2) formed by the imaginary straight line L1 connecting the end point Wl and the apex W2 of the water drop W and the imaginary horizontal straight line L2 on the main surface la of the inorganic member 1 was calculated, and based on the following mathematical expression 1, the contact angle θ was derived. Figure 3

[0152] θ = 2 tan-1(h / r) (Mathematical expression 1)

[0153] h: height of the apex W2

[0154] r: radius of the base of the water drop W

[0155] [Measurement of surface roughness]

[0156] Next, the surface roughness of the main surface of the inorganic member of the samples 1 to 22 was measured.

[0157] The surface roughness of the main surface on which the wet sand blasting treatment was implemented was measured with respect to the samples 1 to 14 and 20 to 22, the surface roughness of one main surface was measured with respect to the samples 15 to 17, the surface roughness of the main surface on which the wet etching treatment based on hydrofluoric acid was implemented was measured with respect to the sample 18, and the surface roughness of the main surface on which the silicon coating film was provided was measured with respect to the sample 19.

[0158] The parameters of the surface roughness measured were the skewness Ssk of the minute concavo-convex formed, the average length RSm of the roughness curve element, the average height Rc of the roughness curve element, the arithmetic average height Sa, and the maximum height Sz, and these measurements were performed using an atomic force microscope (AFM). Note that with respect to the sample 19, the measurement was performed using a laser microscope.

[0159] In addition, based on the above measurement values, the ratio (Rc / RSm) of the average height Rc of the roughness curve element to the average length RSm of the roughness curve element was derived.

[0160] ​Note that the atomic force microscope (AFM) used in the measurement was an atomic force microscope (trade name (SPM unit): Dimension Icon, trade name (Controller unit): Nano Scope V) manufactured by Bruker, and the measurement was performed based on JIS B0601:2013 and ISO 25178.

[0161] In addition, as the measurement conditions, a region of 5 x 5 pm was measured in a tapping mode at a scan rate of 1 Hz and with 512 x 512 data.

[0162] In addition, the laser microscope used in the measurement was a laser microscope (trade name: VK-X250) manufactured by Keyence, and the measurement was performed based on JIS B0601:2013 and ISO 25178.

[0163] In addition, as the measurement conditions, the cutoff value of the high-frequency filter, l c, was set to 50 pm, the cutoff value of the low-frequency filter, l s, was set to 0.5 pm, and a region of about 287 x 215 pm was measured with 2048 x 1536 pixels.

[0164] [Measurement results of contact angle θ and surface roughness]

[0165] The measurement results of the contact angle θ and the surface roughness of Samples 1 to 22 are described.

[0166] Regarding the contact angle θ, the measurement results were as shown in Table 2 below, and regarding the surface roughness, the measurement results were as shown in Tables 2 and 3 below.

[0167] [Table 2]

[0168]

[0169] [Table 3]

[0170]

[0171] As shown in Table 2, in the non-structural members of the examples, i.e., Samples 1 to 14 and 20 to 22, the contact angle θ of the micro concave-convex surface formed was as high as 81° to 96°, which was a good result indicating that the wettability with respect to water was low (i.e., difficult to wet).

[0172] On the other hand, in the non-structured members of Comparative Examples, i.e., Samples 15 to 19, the contact angle Θ of one of the main surfaces (in Sample 18, the main surface on which the wet etching treatment based on hydrofluoric acid was performed, and in Sample 19, the main surface on which the silicon coating film was provided) became a value as low as 14° to 50°, which is considerably lower than in the above-described Examples, and became an undesirable result indicating a higher wettability (i.e., easy wetting) with respect to water.

[0173] Based on the above results, the measurement results of the surface roughness of the non-structured members with respect to Samples 1 to 22 were examined.

[0174] The skewness Ssk was a value in the range of -1.9 to -0.4 in the non-structured members of the Examples, i.e., Samples 1 to 14, 20 to 22.

[0175] On the other hand, in the non-structured members of the Comparative Examples, i.e., Samples 15 to 17, Sample 18 on which the wet etching treatment based on hydrofluoric acid was performed, and Sample 19 on which the silicon coating film was provided, the skewness Ssk was a value in the range of 0 to 1.0, i.e., 0 or a positive value.

[0176] In addition, the average length RSm of the roughness curve elements was a value in the range of 158.4 nm to 582.5 nm in the non-structured members of the Examples, i.e., Samples 1 to 14, 20 to 22, and was in a tendency in which the value of the average length RSm became larger as the treatment pressure of air when the wet sandblasting treatment was performed became higher or as the treatment speed of the nozzle became slower.

[0177] On the other hand, in the non-structured members of Sample 18 on which the wet etching treatment based on hydrofluoric acid was performed and Sample 19 on which the silicon coating film was provided, the average length RSm of the elements of the roughness curve was 1057.5 nm and 11080 nm, respectively, which were considerably larger values than in the above-described Examples.

[0178] Furthermore, the ratio (Rc / RSm) of the average height Rc of the roughness curve elements to the average length RSm of the roughness curve elements was a value in the range of 0.05 to 0.16 in the non-structured members of the Examples, i.e., Samples 1 to 14, 20 to 22, and was in a tendency in which the value of the ratio (Rc / RSm) became larger as the treatment pressure of air when the wet sandblasting treatment was performed became higher or as the treatment speed of the nozzle became slower.

[0179] On the other hand, in the non-structured member of Sample 18 on which the wet etching treatment based on hydrofluoric acid was performed, the ratio (Rc / RSm) of the average height Rc of the roughness curve elements to the average length RSm of the roughness curve elements was 0.01, which was a smaller value than in the above-described Examples.

[0180] In addition, in the non-mechanical member of the sample 19 provided with the silicon coating film, the ratio (Rc / RSm) of the average height Rc of the roughness curve elements to the average length RSm of the roughness curve elements was 0.02, which was a smaller value than in the above-described examples.

[0181] In addition, as shown in Table 3, the arithmetic average height Sa in the non-mechanical members of the examples, i.e., the samples 1 to 14 and 20 to 22, was a value in the range of 3.9 nm to 42.3 nm, and tended to increase as the processing pressure of the air during the wet sand blasting processing or the processing speed of the nozzle increased.

[0182] On the other hand, in the non-mechanical members of the untreated comparative examples, i.e., the samples 15 to 17, and the sample 18 subjected to the wet etching processing based on hydrofluoric acid, the arithmetic average height Sa was a value in the range of 0.2 nm to 3.6 nm, which was a smaller value than in the above-described examples.

[0183] In addition, in the non-mechanical member of the sample 19 provided with the silicon coating film, the arithmetic average height Sa was 120 nm, which was a relatively large value compared to the above-described examples.

[0184] In addition, the maximum height Sz in the non-mechanical members of the examples, i.e., the samples 1 to 14 and 20 to 22, was a value in the range of 117 nm to 371 nm, and tended to increase as the processing pressure of the air during the wet sand blasting processing increased.

[0185] On the other hand, in the non-mechanical members of the untreated comparative examples, i.e., the samples 15 to 17, and the sample 18 subjected to the wet etching processing based on hydrofluoric acid, the maximum height Sz was a value in the range of 2 nm to 42 nm, which was a relatively small value compared to the above-described examples.

[0186] In addition, in the non-mechanical member of the sample 19 provided with the silicon coating film, the maximum height Sz was 2080 nm, which was a relatively large value compared to the above-described examples.

[0187] [Effects]

[0188] As described above, the non-mechanical member 1 of the present embodiment is characterized in that the micro concavo-convex 2 having a skewness Ssk of -0.1 or less is provided in at least a part of the main surface la (surface).

[0189] Thus, in the present embodiment, the skewness Ssk of the micro concavo-convex 2 formed is a negative value, and the micro concavo-convex 2 has a shape in which the average height of the concave portions is higher than the average height of the convex portions. Figure 2As shown in (a), it is composed of concave and convex shapes with valleys Ya, Ya... that are narrower than the peaks Xa1. Therefore, it has high rigidity and excellent durability, and can be easily formed by colliding the particles with the main surface 1a of the unstructured part 1 using shot peening or the like.

[0190] In addition, such as Figure 3 As shown, in the main surface (surface) 1a of the mechanical component 1 with the micro-protrusions 2, an air layer Q is maintained in the recess 21 of the micro-protrusions 2. Therefore, compared with a smooth plane without micro-protrusions 2, the contact angle θ of the water droplet W attached to the main surface (surface) 1a can be increased, and lower wettability to water can be achieved.

[0191] Furthermore, the non-mechanical component 1 in this embodiment is preferably made of glass.

[0192] With this configuration, it is possible to obtain a mechanical component 1 that has high light transmittance and excellent processability.

[0193] Furthermore, in this embodiment, the mechanical component 1 preferably has an average length RSm of 30 nm or more and 750 nm or less in the micro-bumps 2.

[0194] Thus, by setting the range of the average length RSm of the roughness curve element as described above, it is possible to make the formation of the micro-protrusions 2 simpler, and to prevent water droplets W adhering to the main surface 1a of the non-mechanical component 1 from entering the recess 21 of the micro-protrusions 2 and reducing the contact angle θ.

[0195] Furthermore, in this embodiment, the mechanical component 1 preferably has a ratio (Rc / RSm) of the average height Rc of the roughness curve element to the average length RSm of the roughness curve element in the micro-bumps 2 being 0.02 or more and 1.00 or less.

[0196] Thus, by setting the range of the hypothetical aspect ratio of the micro-protrusion 2, i.e. the ratio of the average height Rc of the roughness curve element to the average length RSm of the roughness curve element (Rc / RSm), as described above, the height of the protrusion in the protrusion shape of the micro-protrusion 2 is suppressed, damage caused by wear and the like can be suppressed, the durability of the micro-protrusion 2 is improved, and the contact angle of water droplets W adhering to the main surface (surface) 1a of the non-mechanical component 1 can be prevented from decreasing for a long time.

[0197] Furthermore, in this embodiment, the non-mechanical component 1 preferably has an arithmetic mean height Sa of 1 nm or more and 100 nm or less in the micro-protrusions 2.

[0198] Thus, by setting the range of the arithmetic mean height Sa as described above, it is possible to more effectively maintain the air layer Q in the recessed portions 21 of the fine irregularities 2, and more reliably increase the contact angle Θ of the water droplet W adhering to the main face (surface) la of the inorganic member 1 compared to a smooth plane not having the fine irregularities 2, and to achieve a lower wettability to water.

[0199] In addition, it is possible to minimize the scattering of light caused by the irregularities of the fine irregularities 2, and more reliably ensure the transparency of the main face (surface) la of the inorganic member 1 formed with the fine irregularities 2.

[0200] In addition, the inorganic member 1 of the present embodiment is preferably such that, in the fine irregularities 2, the maximum height Sz is 30 nm or more and 500 nm or less.

[0201] Thus, by setting the range of the maximum height Sz as described above, it is possible to further effectively maintain the air layer Q in the recessed portions 21 of the fine irregularities 2, and more reliably increase the contact angle Θ of the water droplet W adhering to the main face (surface) la of the inorganic member 1 compared to a smooth plane not having the fine irregularities 2, and to achieve a lower wettability to water.

[0202] In addition, it is possible to further reliably minimize the scattering of light caused by the irregularities of the fine irregularities 2, and more reliably ensure the transparency of the main face (surface) la of the inorganic member 1 formed with the fine irregularities 2.

[0203] Furthermore, the inorganic member 1 of the present embodiment can also be characterized in that the fine irregularities 2 are provided on at least a portion of the main face la (surface), and that, instead of the above-described characteristics, the ratio (Rc / RSm) of the average height Rc of the roughness curve elements of the fine irregularities 2 to the average length RSm of the roughness curve elements is 0.02 or more and 1.00 or less.

[0204] If the inorganic member 1 is configured by such a structure, the durability of the fine irregularities 2 formed on at least the main face la (surface) of the inorganic member 1 is improved, and it is possible to prevent the decrease in the contact angle of the water droplet W adhering to the main face la for a long period of time.

[0205] Furthermore, the manufacturing method of the inorganic member 1 of the present embodiment is a method of manufacturing any one of the above-described inorganic members 1, characterized in that a wet blasting process is performed on at least a portion of the main face (surface) la of the inorganic member 1, thereby forming the fine irregularities 2.

[0206] According to the manufacturing method configured by this structure, it is possible to obtain the inorganic member 1 in which the fine unevenness 2 is formed on the main surface (surface) 1a and the contact angle Θ of the water droplet W attached to the main surface (surface) 1a of the inorganic member 1 is increased compared with the smooth surface not having the fine unevenness 2 and the wettability for water is lower.

[0207] Industrial applicability

[0208] The inorganic member and the manufacturing method of the inorganic member of the present application can be utilized as an inorganic member having lower wettability for water, for example, in the fields of window panels of automobiles, railway vehicles, ships, and aircrafts, ophthalmic lenses, and lenses of photographic devices.

[0209] Explanation of reference numerals

[0210] 1 inorganic member

[0211] 1a main surface (surface)

[0212] 2 fine unevenness

[0213] 2a roughness curve

[0214] RSm average length of roughness curve element

[0215] Rc average height of roughness curve element

[0216] Sa arithmetic average height

[0217] Ssk skewness

[0218] Sz maximum height.

Claims

1. An inorganic member characterized by comprising: the inorganic member has minute irregularities on at least a part of a surface, the skewness Ssk of the minute irregularities is -0.1 or less, a ratio (Rc / RSm) of the average height Rc of the roughness curve elements to the average length RSm of the roughness curve elements is 0.50 or less.

2. The inorganic member according to claim 1, characterized by comprising: the inorganic member is composed of glass.

3. The inorganic member according to claim 1, characterized by comprising: in the minute irregularities, the average length RSm of the roughness curve elements is 30 nm or more and 750 nm or less.

4. The inorganic member according to any one of claims 1 to 3, characterized by comprising: in the minute irregularities, a ratio (Rc / RSm) of the average height Rc of the roughness curve elements to the average length RSm of the roughness curve elements is 0.02 or more and 0.50 or less.

5. The inorganic member according to any one of claims 1 to 3, characterized by comprising: in the minute irregularities, the arithmetic average height Sa is 1 nm or more and 100 nm or less.

6. The inorganic member according to any one of claims 1 to 3, characterized by comprising: in the minute irregularities, the maximum height Sz is 30 nm or more and 500 nm or less.

7. An inorganic member characterized by comprising: the inorganic member has minute irregularities on at least a part of a surface, a ratio (Rc / RSm) of the average height Rc of the roughness curve elements to the average length RSm of the roughness curve elements of the minute irregularities is 0.03 or more and 0.50 or less.

8. A method for manufacturing an inorganic member, which is a method for manufacturing the inorganic member according to any one of claims 1 to 7, characterized by comprising: performing a wet sand blasting treatment on at least a part of a surface of the inorganic member, thereby forming the minute irregularities.

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