WO2022054961A1

WO2022054961A1 - Cover member

Info

Publication number: WO2022054961A1
Application number: PCT/JP2021/033815
Authority: WO
Inventors: 瑞穂小用
Original assignee: 日本板硝子株式会社
Priority date: 2020-09-14
Filing date: 2021-09-14
Publication date: 2022-03-17
Also published as: AR123456A1; JP2022048047A

Abstract

Provided is a cover member that can achieve both anti-glare performance and anti-bacterial performance. This cover member comprises: a plate-shaped substrate that has a first surface and a second surface, the first surface having a prescribed surface roughness; and an anti-bacterial film which is formed on the first surface. The anti-bacterial film comprises: a retaining layer which is formed on the first surface; and anti-bacterial fine particles which are retained by the retaining layer, and which have an average particle diameter that is at least equal to the film thickness of the retaining layer.

Description

Cover member

The present invention relates to a cover member provided on a protected member such as a display.

Patent Document 1 discloses a glass substrate provided with a functional layer having fingerprint resistance. This glass substrate is used as a cover member for touching a finger such as a touch sensor. Further, it is disclosed that the functional layer of the glass substrate has functions such as anti-glare function and antibacterial function in addition to fingerprint resistance.

Japanese Patent Publication No. 2017-528411

By the way, Patent Document 1 discloses that when a functional layer having a plurality of functions as described above is provided, the plurality of functions are exerted by one functional layer. For example, an antiglare function and an antibacterial function are provided. It is conceivable to provide a functional layer to have. However, a specific functional layer having an antiglare function and an antibacterial function has not yet been proposed, and a cover member having such a functional layer has been desired. The present invention has been made to solve this problem, and an object of the present invention is to provide a cover member having antiglare performance and antibacterial performance.

Item 1. A plate-shaped base material having a first surface and a second surface, the first surface having a predetermined surface roughness,
The antibacterial film formed on the first surface and
Equipped with
The antibacterial membrane is
The holding layer formed on the first surface and
A cover member comprising: antibacterial fine particles held by the holding layer and having an average particle size equal to or larger than the film thickness of the holding layer.

Item 2. Item 2. The cover member according to Item 1, wherein the surface roughness of the holding layer is smaller than the surface roughness of the first surface of the base material and smaller than 120 nm.

Item 3. Item 2. The cover member according to

Item

1 or 2, wherein the maximum film thickness of the holding layer is smaller than the surface roughness of the base material.

Item 4. Item 2. The cover member according to any one of Items 1 to 3, wherein the holding layer of the antibacterial film contains silicon oxide as a main component.

Item 5. The base material is formed of a glass plate having the first surface and the second surface.
Item 4. The cover member according to any one of Items 1 to 4.

Item 6. Item 5. The cover member according to Item 5, wherein the glass plate is formed of float glass, and the bottom surface of the float glass constitutes the first surface.

Item 7. Item 2. The cover member according to any one of Items 1 to 4, wherein the base material comprises a glass plate and a base layer formed on one surface of the glass plate and having the predetermined surface roughness.

Item 8. Item 7. The cover member according to Item 7, wherein the base layer includes a base layer containing silicon oxide as a main component and fine particles held in the base layer.

Item 9. Item 7. The cover member according to Item 7 or 8, wherein the glass plate is formed of float glass, and the base layer is formed on the top surface of the float glass.

Item 10. Item 2. The cover member according to any one of Items 5 to 9, wherein the thickness of the glass plate is 3 mm or less.

Item 11. Item 2. The cover member according to Item 10, wherein the average particle size of the fine particles is smaller than the average particle size of the antibacterial fine particles.

Item 12. Item 2. The cover member according to any one of Items 1 to 11, wherein the distance between the antibacterial fine particles on the holding layer is 1 to 200 μm.

Item 13. Item 2. The cover member according to any one of Items 1 to 12, wherein the average particle size of the antibacterial fine particles is 0.1 to 10 μm.

Item 14. Item 2. The cover member according to any one of Items 1 to 13, wherein a fingerprint-resistant layer formed on at least a part of the antibacterial film is formed.

Item 15. Item 12. The cover member according to Item 14, wherein the fingerprint-resistant layer has a thinner film thickness than the antibacterial film.

Item 16. Item 2. The cover member according to Item 14 or 15, wherein the fingerprint-resistant layer is formed on a part of the antibacterial film.

Item 17. Item 2. The cover member according to any one of Items 1 to 16, wherein the antibacterial fine particles are made of copper.

Item 18. Item 2. The cover member according to any one of Items 1 to 17, further comprising an antireflection film arranged between the base material and the antibacterial film.

Item 19. Item 6. The cover member according to any one of Items 1 to 18, which is arranged so as to cover the surface of a display, a keyboard, or an electronic blackboard.

According to the present invention, it is possible to provide a cover member having both antiglare performance and antibacterial performance.

It is sectional drawing which shows one Embodiment of the cover member which concerns on this invention. It is an enlarged sectional view of FIG. It is a photograph which shows the surface property of the antibacterial film which concerns on Example. It is an enlarged photograph of the antibacterial fine particles of the antibacterial film which concerns on Example.

Hereinafter, an embodiment of the cover member according to the present invention will be described with reference to the drawings. The cover member according to the present embodiment is configured to protect protected members such as a display, a keyboard, and an electronic blackboard, and to make these members visible from the outside. The display includes not only a general desktop display but also a display used for various devices such as mobile PCs, tablet PCs, and in-vehicle devices such as car navigation systems. FIG. 1 is a cross-sectional view of a cover member.

As shown in FIG. 1, the cover member 10 according to the present embodiment includes a glass plate 1 having a first surface and a second surface, and an antibacterial film 2 laminated on the first surface of the glass plate 1. ing. Then, the cover member 10 is arranged so as to cover the above-mentioned protected member 100. At this time, the second surface of the glass plate 1 is arranged so as to face the protected member 100, and the antibacterial film 2 is arranged so as to face the outside. Hereinafter, it will be described in detail.

<1. Glass plate>
The glass plate 1 can be formed of, for example, other glass such as general-purpose soda lime glass, borosilicate glass, aluminosilicate glass, and non-alkali glass. Further, the glass plate 1 can be molded by the float method. According to this manufacturing method, a glass plate 1 having a smooth surface can be obtained. However, the glass plate 10 may have irregularities on the main surface, and may be, for example, template glass. The template glass can be molded by a manufacturing method called a rollout method. The template glass produced by this method usually has periodic irregularities in one direction along the main surface of the glass plate.

In the float method, molten glass is continuously supplied on a molten metal such as molten tin, and the supplied molten glass is made to flow on the molten metal to form a strip. The glass thus formed is called a glass ribbon.

The glass ribbon is cooled toward the downstream side, cooled and solidified, and then pulled up from the molten metal by a roller. Then, it is transported to a slow cooling furnace by a roller, slowly cooled, and then cut. In this way, a float glass plate is obtained. Here, in the float glass plate, the surface in contact with the molten metal is referred to as a bottom surface, and the surface opposite to the bottom surface is referred to as a top surface. The bottom surface and the top surface may be unpolished. Since the bottom surface is in contact with the molten metal, when the molten metal is tin, the concentration of tin oxide contained in the bottom surface is higher than the concentration of tin oxide contained in the top surface. In the present embodiment, the first surface of the glass plate 1 is the bottom surface, and the second surface is the top surface.

Further, since the bottom surface, that is, the second surface, is pulled up from the molten metal and then conveyed by the rollers, it is known that the rollers cause scratches called so-called microcracks. Therefore, in general, the bottom surface of the float glass plate has more scratches than the top surface.

The bottom surface of the glass plate 1 is etched to remove a layer having a high concentration of tin oxide. Since tin oxide has a large refractive index, it is possible to improve the transmittance by removing it. Further, by etching, a fine unevenness having a predetermined surface roughness is formed on the bottom surface. The surface roughness Ra of the bottom surface is, for example, preferably 10 to 500 nm, more preferably 40 to 200 nm, and particularly preferably 50 to 150 nm. Ra is the arithmetic mean roughness of the roughness curve defined by JIS B0601: 2001. This point is the same in the holding layer 21 of the antibacterial film 2 described later.

Other methods for forming a predetermined surface roughness on a glass plate include surface treatments such as frost treatment, sandblast treatment, and wet blast treatment. The frost treatment is a treatment for forming irregularities on the surface of the glass plate by, for example, immersing the glass plate in a mixed solution of hydrogen fluoride and ammonium fluoride and chemically surface-treating the immersed surface. The sandblasting treatment is a treatment for forming irregularities on the surface of the glass plate by, for example, blowing crystalline silicon dioxide powder, silicon carbide powder, or the like onto the surface of the glass plate with pressurized air. Further, after the unevenness is created in this way, it is generally performed to chemically etch the surface of the glass plate in order to adjust the surface shape. By doing so, cracks generated by sandblasting or the like can be removed. As the etching, a method of immersing a glass plate as an object to be treated in a solution containing hydrogen fluoride as a main component is preferably used.

Wet blasting is a high-speed process in which abrasive grains composed of solid particles such as alumina and a liquid such as water are uniformly agitated into a slurry from an injection nozzle to the surface of a glass plate using compressed air. It is a process of forming unevenness on the surface of the glass plate by injecting with.

The thickness of the glass plate 1 is not particularly limited, but it is better to be thin for weight reduction. For example, it is preferably 0.3 to 3 mm, and more preferably 0.6 to 2.5 mm. This is because if the glass plate 10 is too thin, the strength is lowered, and if it is too thick, the protected member 100 visually recognized via the cover member 10 may be distorted.

The glass plate 1 is usually a flat plate, but may be a curved plate. In particular, when the surface shape of the protected member to be protected is a non-planar surface such as a curved surface, it is preferable that the glass plate 1 has a non-planar main surface suitable for the surface shape. In this case, the glass plate 1 may be bent so as to have a constant curvature as a whole, or may be locally bent. The main surface of the glass plate 1 may be configured by, for example, a plurality of planes connected to each other by a curved surface. The radius of curvature of the glass plate 1 can be, for example, 5000 mm or less. The lower limit of the radius of curvature can be, for example, 10 mm or more, but may be even smaller, for example, 1 mm or more, especially in a locally bent portion.

A glass plate having the following composition can also be used. In the following, the% indications indicating the components of the glass plate 1 mean mol% unless otherwise specified. Further, in the present specification, "substantially composed" means that the total content of the listed components is 99.5% by mass or more, preferably 99.9% by mass or more, and more preferably 99.95. It means that it occupies more than mass%. "Substantially free" means that the content of the component is 0.1% by mass or less, preferably 0.05% by mass or less.

The present invention is based on the composition of float glass (hereinafter, may be referred to as "SL in a narrow sense" or simply "SL") widely used as a glass composition suitable for producing a glass plate by the float method. , Composition range considered by those skilled in the art as soda lime silicate glass suitable for the float method (hereinafter, may be referred to as "SL in a broad sense"), specifically, within the following mass% range. Therefore, a composition capable of improving the chemically strengthened properties of SL in a narrow sense while making the properties of T ₂ , T ₄ , etc. as close as possible to SL in a narrow sense was investigated.
SiO ₂ 65-80%
Al ₂ O _30-16 %
MgO 0-20%
CaO 0-20%
Na ₂ O 10-20%
K ₂ O 0-5%

Hereinafter, each component constituting the glass composition of the glass plate 1 will be described.
(SiO ₂ )
SiO ₂ is a main component constituting the glass plate 1, and if the content thereof is too low, the chemical durability and heat resistance such as water resistance of the glass are lowered. On the other hand, if the content of SiO ₂ is too high, the viscosity of the glass plate 1 at a high temperature becomes high, which makes melting and molding difficult. Therefore, the content of SiO ₂ is appropriately in the range of 66 to 72 mol%, preferably 67 to 70 mol%.

(Al ₂ O ₃ )
Al ₂ O ₃ improves the chemical durability of the glass plate 1 such as water resistance, and further facilitates the movement of alkali metal ions in the glass to increase the surface compressive stress after chemical strengthening, and the stress layer. It is an ingredient for deepening the depth. On the other hand, if the content of Al ₂ O ₃ is too high, the viscosity of the glass melt is increased, T ₂ and T ₄ are increased, and the clarity of the glass melt is deteriorated to produce a high-quality glass plate. Becomes difficult.

Therefore, it is appropriate that the content of Al ₂ O ₃ is in the range of 1 to 12 mol%. The content of Al ₂ O ₃ is preferably 10 mol% or less, preferably 2 mol% or more.

(MgO)
MgO is an essential component that improves the solubility of glass. From the viewpoint of obtaining this effect, it is preferable that MgO is added to the glass plate 1. Further, when the content of MgO is less than 8 mol%, the surface compressive stress after chemical strengthening tends to decrease, and the depth of the stress layer tends to become shallow. On the other hand, if the content is increased beyond an appropriate amount, the strengthening performance obtained by chemical strengthening deteriorates, and in particular, the depth of the surface compressive stress layer sharply becomes shallow. This adverse effect has the least MgO among alkaline earth metal oxides, but the content of MgO in this glass plate 1 is 15 mol% or less. Further, when the content of MgO is high, T ₂ and T ₄ are increased, and the clarity of the glass melt is deteriorated, which makes it difficult to manufacture a high-quality glass plate.

Therefore, in this glass plate 1, the content of MgO is in the range of 1 to 15 mol%, preferably 8 mol% or more and 12 mol% or less.

(CaO)
CaO has the effect of reducing the viscosity at high temperatures, but if the content is too high beyond an appropriate range, the glass plate 1 tends to be devitrified and the movement of sodium ions in the glass plate 1 is inhibited. I will. When CaO is not contained, the surface compressive stress after chemical strengthening tends to decrease. On the other hand, when CaO is contained in an amount of more than 8 mol%, the surface compressive stress after chemical strengthening is remarkably reduced, the depth of the compressive stress layer is remarkably shallow, and the glass plate 1 is easily devitrified.

Therefore, it is appropriate that the CaO content is in the range of 1 to 8 mol%. The CaO content is preferably 7 mol% or less, preferably 3 mol% or more.

(SrO, BaO)
SrO and BaO greatly reduce the viscosity of the glass plate 1, and when contained in a small amount, the effect of lowering the liquidus temperature _TL is more remarkable than that of CaO. However, SrO and BaO remarkably hinder the movement of sodium ions in the glass plate 1 even when added in a very small amount, greatly reduce the surface compressive stress, and the depth of the compressive stress layer becomes considerably shallow.

Therefore, it is preferable that the glass plate 1 does not substantially contain SrO and BaO.

(Na ₂ O)
Na ₂ O is a component for increasing the surface compressive stress and deepening the depth of the surface compressive stress layer by substituting sodium ions with potassium ions. However, when the content is increased beyond an appropriate amount, the stress relaxation during the chemical strengthening treatment exceeds the generation of surface compressive stress due to ion exchange in the chemical strengthening treatment, and as a result, the surface compressive stress tends to decrease. be.

Further, Na ₂ O is a component for improving the solubility and lowering T ₄ and T ₂ , while if the content of Na ₂ O is too high, the water resistance of the glass is significantly lowered. In the glass plate 1, if the Na ₂ O content is 10 mol% or more, the effect of reducing T ₄ and T ₂ is sufficiently obtained, and if it exceeds 16 mol%, the surface compressive stress is significantly reduced due to stress relaxation. Become.

Therefore, the Na ₂ O content in the glass plate 1 of the present embodiment is appropriately in the range of 10 to 16 mol%. The Na ₂ O content is preferably 12 mol% or more, more preferably 15 mol% or less.

(K ₂ O)
Like Na ₂ O, K ₂ O is a component that improves the solubility of glass. Further, in the range where the K ₂ O content is low, the ion exchange rate in chemical strengthening increases and the depth of the surface compressive stress layer becomes deep, while the liquidus temperature _TL of the glass plate 1 decreases. Therefore, it is preferable to contain K ₂ O at a low content.

On the other hand, K ₂ O has a smaller effect of lowering T ₄ and T ₂ than Na ₂ O, but a large amount of K ₂ O inhibits the clarification of the glass melt. Further, the higher the K ₂ O content, the lower the surface compressive stress after chemical strengthening. Therefore, it is appropriate that the content of K ₂ O is in the range of 0 to 1 mol%.

(Li ₂ O)
Li ₂ O significantly reduces the depth of the compressive stress layer even if it is contained in a small amount. Further, when the glass article containing Li ₂ O is chemically strengthened with the molten salt of potassium nitrate alone, the rate of deterioration of the molten salt is significantly faster than that of the glass article containing no Li ₂ O. Specifically, when the same molten salt is repeatedly subjected to the chemical strengthening treatment, the surface compressive stress formed on the glass surface is reduced with a smaller number of times. Therefore, the glass plate 1 of the present embodiment may contain 1 mol% or less of Li ₂ O, but it is preferable that the glass plate 1 does not contain Li ₂ O substantially.

(B ₂ O ₃ )
B ₂ O ₃ is a component that lowers the viscosity of the glass plate 1 and improves the solubility. However, if the content of B ₂ O ₃ is too high, the glass plate 1 tends to be phase-separated, and the water resistance of the glass plate 1 is lowered. In addition, the compound formed by B ₂ O ₃ and the alkali metal oxide may volatilize and damage the refractory in the glass melting chamber. Furthermore, the inclusion of B ₂ O ₃ shallows the depth of the compressive stress layer during chemical strengthening. Therefore, it is appropriate that the content of B ₂ O ₃ is 0.5 mol% or less. In the present invention, it is more preferable that the glass plate 1 contains substantially no B ₂ O ₃ .

(Fe ₂ O ₃ )
Normally, Fe exists in glass in the state of Fe ²⁺ or Fe ³⁺ and acts as a colorant. Fe ³⁺ is a component that enhances the ultraviolet absorption performance of glass, and Fe ²⁺ is a component that enhances the heat ray absorption performance. When the glass plate 1 is used as a cover glass for a display, it is required that the coloring is inconspicuous, so that the Fe content is preferably low. However, Fe is often unavoidably mixed with industrial raw materials. Therefore, the iron oxide content converted to Fe ₂ O ₃ is often 0.15% by mass or less, and more preferably 0.1% by mass or less, with the entire glass plate 1 as 100% by mass. It is preferable, more preferably 0.02% by mass or less.

(TiO ₂ )
TiO ₂ is a component that lowers the viscosity of the glass plate 1 and at the same time increases the surface compressive stress due to chemical strengthening, but may give the glass plate 1 a yellow color. Therefore, it is appropriate that the content of TiO ₂ is 0 to 0.2% by mass. In addition, it is inevitably mixed with an industrial raw material that is usually used, and may be contained in the glass plate 1 in an amount of about 0.05% by mass. Since the glass is not colored if the content is at this level, it may be contained in the glass plate 1 of the present embodiment.

(ZrO ₂ )
ZrO ₂ may be mixed into the glass plate 1 from the refractory bricks constituting the glass melting kiln, especially when the glass plate is manufactured by the float method, and the content thereof may be about 0.01% by mass. Are known. On the other hand, ZrO ₂ is a component that improves the water resistance of glass and also enhances the surface compressive stress due to chemical strengthening. However, a high content of ZrO ₂ may cause an increase in the working temperature T ₄ and a sharp increase in the liquid phase temperature _TL , and in the production of a glass plate by the float method, crystals containing precipitated Zr are present. It tends to remain as a foreign substance in the manufactured glass. Therefore, it is appropriate that the content of ZrO ₂ is 0 to 0.1% by mass.

(SO ₃ )
In the float method, sulfates such as Glauber's salt (Na ₂ SO ₄ ) are widely used as clarifying agents. The sulfate decomposes in the molten glass to generate a gas component, which promotes defoaming of the glass melt, but a part of the gas component dissolves and remains in the glass plate 1 as SO ₃ . In the glass plate 1 of the present invention, SO ₃ is preferably 0 to 0.3% by mass.

(CeO ₂ )
CeO ₂ is used as a clarifying agent. CeO ₂ contributes to defoaming because O ₂ gas is generated in the molten glass by CeO ₂ . On the other hand, if there is too much CeO ₂ , the glass will be colored yellow. Therefore, the content of CeO ₂ is preferably 0 to 0.5% by mass, more preferably 0 to 0.3% by mass, and even more preferably 0 to 0.1% by mass.

(SnO ₂ )
It is known that in a glass plate formed by the float method, tin diffuses from the tin bath on the surface in contact with the tin bath during molding, and the tin exists as SnO ₂ . In addition, SnO ₂ mixed with the glass raw material contributes to defoaming. In the glass plate 1 of the present invention, SnO ₂ is preferably 0 to 0.3% by mass.

(Other ingredients)
It is preferable that the glass plate 1 according to the present embodiment is substantially composed of the components listed above. However, the glass plate 1 according to the present embodiment may contain components other than the components listed above, preferably in a range in which the content of each component is less than 0.1% by mass.

Examples of the components permitted to be contained include As ₂ O ₅ , Sb ₂ O ₅ , Cl, and F added for the purpose of defoaming the molten glass in addition to the above-mentioned SO ₃ and Sn O ₂ . However, it is preferable not to add As ₂ O ₅ , Sb ₂ O ₅ , Cl, and F because they have a large adverse effect on the environment. In addition, another example in which the content is allowed is ZnO, P ₂ O ₅ , GeO ₂ , Ga ₂ O ₃ , Y ₂ O ₃ , and La ₂ O ₃ . Even components other than the above derived from industrially used raw materials are permitted as long as they do not exceed 0.1% by mass. Since these components are appropriately added or inevitably mixed as needed, the glass plate 1 of the present embodiment may be substantially free of these components. do not have.

(Density (specific gravity): d)
From the above composition, in the present embodiment, the density of the glass plate 1 is reduced to 2.53 g · cm ^-3 or less, further to 2.51 g · cm ^-3 or less, and in some cases 2.50 g · cm ^-3 or less. be able to.

In the float method, if there is a large difference in density between glass types, the higher density molten glass may stay at the bottom of the melting kiln when switching between glass types to be manufactured, which may hinder the switching of glass types. .. Currently, the density of soda lime glass mass-produced by the float method is about 2.50 g · cm ^-3 . Therefore, considering mass production by the float method, the density of the glass plate 1 is close to the above value, specifically, 2.45 to 2.55 g · cm ^-3 , especially 2.47 to 2.53 g ·. cm ^-3 is preferable, and 2.47 to 2.50 g · cm ^-3 is more preferable.

(Elastic modulus: E)
Chemical strengthening with ion exchange may cause the glass substrate to warp. In order to suppress this warpage, it is preferable that the elastic modulus of the glass plate 1 is high. According to the present invention, the elastic modulus (Young's modulus: E) of the glass plate 1 can be increased to 70 GPa or more, and further to 72 GPa or more.

Hereinafter, the chemical strengthening of the glass plate 1 will be described.
(Chemical strengthening conditions and compressive stress layer)
The glass plate 1 containing sodium is brought into contact with a molten salt containing a monovalent cation having an ionic radius larger than that of the sodium ion, preferably a potassium ion, and the sodium ion in the glass plate 1 is brought into contact with the above monovalent cation. The chemical strengthening of the glass plate 1 according to the present invention can be carried out by performing the ion exchange treatment of replacement by. As a result, a compressive stress layer to which compressive stress is applied to the surface is formed.

Typical examples of the molten salt include potassium nitrate. A mixed molten salt of potassium nitrate and sodium nitrate can also be used, but since it is difficult to control the concentration of the mixed molten salt, a molten salt of potassium nitrate alone is preferable.

The surface compressive stress and the compressive stress layer depth in the tempered glass article can be controlled not only by the glass composition of the article but also by the temperature and treatment time of the molten salt in the ion exchange treatment.

By contacting the above glass plate 1 with the molten salt of potassium nitrate, it is possible to obtain a tempered glass article having a very high surface compressive stress and a very deep compressive stress layer. Specifically, a tempered glass article having a surface compressive stress of 700 MPa or more and a compressive stress layer depth of 20 μm or more can be obtained, and further, a compressive stress layer depth of 20 μm or more and a surface compressive stress of 750 MPa or more. You can also get certain tempered glass articles.

<2. Antibacterial membrane>
Next, the antibacterial membrane 2 will be described with reference to FIG. FIG. 2 is an enlarged cross-sectional view showing an outline of the antibacterial membrane. As shown in FIG. 2, the antibacterial film 2 includes a holding layer 21 laminated on the first surface of the glass plate 1 and antibacterial fine particles 22 held by the holding layer 21. These will be described below.

<2-1. Retention layer>
Since the holding layer 21 is laminated on the first surface of the glass plate 1, unevenness is also formed on the surface of the holding layer 21 along the unevenness of the first surface. Since the surface roughness Ra of the holding layer 21 is smaller than the surface roughness of the first surface of the glass plate 1, it is preferably 120 nm or less, more preferably 100 nm or less, for example. On the other hand, the surface roughness Ra of the holding layer 21 is preferably, for example, 20 nm or more, and more preferably 40 nm or more. As described above, when the surface roughness Ra of the holding layer 21 is 20 nm or more and smaller than 120 nm, the antiglare function is exhibited. The Rsm on the surface of the holding layer is preferably more than 0 μm and 35 μm or less, more preferably 1 μm to 30 μm, and particularly preferably 2 μm to 20 μm. Rsm is the average length of the roughness curve elements defined by JIS B0601: 2001. Rsm that is not too large is suitable for suppressing so-called sparkles.

The maximum thickness D of the holding layer 21 is, for example, preferably 10 to 500 nm, more preferably 20 to 200 nm, and particularly preferably 30 to 80 nm. If the maximum thickness D is too thick, the antibacterial fine particles 22 described later may be buried in the holding layer 21, and the antibacterial function may be suppressed. In addition, there is a risk that the holding layer 21 may be peeled off from the glass plate 1 or the film may be cracked. On the other hand, if the maximum thickness D is too thin, the antibacterial fine particles 22 cannot be retained, and the antibacterial fine particles may be detached from the holding layer 21, which is not preferable. Here, the maximum thickness D means the thickness from the deepest concave portion of the first surface of the glass plate 1 to the highest convex portion of the holding layer 21 as shown in FIG.

The holding layer 21 serves as a binder for holding antibacterial fine particles. The holding layer 2 contains silicon oxide, which is an oxide of Si, and preferably contains silicon oxide as a main component. The holding layer 21 containing silicon oxide as a main component is suitable for lowering the refractive index of the film and suppressing the reflectance of the film. The holding layer 21 may contain a component other than silicon oxide, or may contain a component partially containing silicon oxide.

The component partially containing silicon oxide includes, for example, a portion composed of a silicon atom and an oxygen atom, and is a component in which an atom other than both atoms, a functional group or the like is bonded to the silicon atom or the oxygen atom in this portion. .. Examples of the atom other than the silicon atom and the oxygen atom include a nitrogen atom, a carbon atom, a hydrogen atom, and a metal element described in the next paragraph. As the functional group, for example, an organic group described as R in the next paragraph can be exemplified. Strictly speaking, such a component is not silicon oxide in that it is not composed only of silicon atoms and oxygen atoms. However, in describing the characteristics of the holding layer 21, it is appropriate to treat the silicon oxide portion composed of silicon atoms and oxygen atoms as "silicon oxide", which is consistent with the practice in the art. In the present specification, the silicon oxide portion is also treated as silicon oxide. As is clear from the above explanation, the atomic ratio of a silicon atom to an oxygen atom in silicon oxide does not have to be stoichiometric (1: 2).

The holding layer 21 may contain a metal oxide other than silicon oxide, specifically, a metal oxide component or a metal oxide portion containing other than silicon. The metal oxide that can be contained in the holding layer 21 is not particularly limited, but is, for example, an oxide of at least one metal element selected from the group consisting of Al, Ti, Zr, Ta, Nb, Nd, La, Ce and Sn. Is. The holding layer 21 may contain an inorganic compound component other than an oxide, for example, a nitride, a carbide, a halide, or the like, or may contain an organic compound component.

Metal oxides such as silicon oxide can be formed from hydrolyzable organometallic compounds. Examples of the hydrolyzable silicon compound include the compound represented by the formula (1).
R _n SiY _4-n (1)
R is an organic group containing at least one selected from an alkyl group, a vinyl group, an epoxy group, a styryl group, a methacryloyl group and an acryloyl group. Y is a hydrolyzable organic group or a halogen atom which is at least one selected from an alkoxy group, an acetoxy group, an alkenyloxy group and an amino group. The halogen atom is preferably Cl. n is an integer from 0 to 3, preferably 0 or 1.

As R, an alkyl group, for example, an alkyl group having 1 to 3 carbon atoms, particularly a methyl group is suitable. As Y, an alkoxy group, for example, an alkoxy group having 1 to 4 carbon atoms, particularly a methoxy group and an ethoxy group are suitable. Two or more compounds represented by the above formula may be used in combination. Examples of such a combination include a combination of a tetraalkoxysilane in which n is 0 and a monoalkyltrialkoxysilane in which n is 1.

The compound represented by the formula (1) forms a network structure in which silicon atoms are bonded to each other via oxygen atoms after hydrolysis and polycondensation. In this structure, the organic group represented by R is contained in a state of being directly bonded to a silicon atom.

<2-2. Antibacterial fine particles>
The antibacterial fine particles 22 may contain fine particles having an antibacterial function, for example, made of copper, silver, zinc oxide, or the like. The antibacterial fine particles 22 can be aggregates of these fine particles, but can also be aggregates containing dispersants and binders in addition to these fine particles. Alternatively, it can be the fine particles that are not aggregates. However, in the following, for convenience of explanation, the term "antibacterial fine particles" means an aggregate of fine particles unless otherwise specified. The average particle size of the fine particles constituting the aggregate is, for example, preferably 10 to 150 nm, more preferably 15 to 100 nm, and particularly preferably 20 to 80 nm. The average particle size of the antibacterial fine particles 22 which are aggregates is larger than the maximum thickness of the holding layer 21, for example, preferably 0.1 to 10 μm, and more preferably 0.5 to 5 μm. It is particularly preferably 1 to 4 μm. As a result, the antibacterial fine particles 22 protrude from the holding layer 21 and exert an antibacterial function. The antibacterial fine particles 22 may be covered with the holding layer 21, but even if the holding layer 21 is covered, the antibacterial function is not significantly suppressed because the holding layer 21 is thin.

Further, the interval L of the antibacterial fine particles 22 held in the holding layer 21 is preferably 1 to 200 μm, more preferably 2 to 100 μm, and particularly preferably 3 to 70 μm. If the distance L between the antibacterial fine particles 22 is too narrow, the area of the holding layer 21 exposed between them becomes narrow, and the antiglare function may be impaired. On the other hand, if the distance L between the antibacterial fine particles 22 is too wide, the antibacterial function may be reduced. The method for measuring the average particle size of the antibacterial fine particles 22 and the interval between the antibacterial fine particles 22 is described in Section (6) of Examples described later.

The content of the antibacterial fine particles contained in the antibacterial membrane 2 is preferably 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 18% by weight or less, and 15% by weight or less in this order. On the other hand, the lower limit is preferably 0.1% by weight or more, 5% by weight or more, and 10% by weight or more in this order.

<2-3. Method of forming antibacterial film>
The method for forming the antibacterial film 2 is not particularly limited, but can be formed as follows, for example. First, a material constituting the above-mentioned matrix, for example, tetraethoxysilane is used as a solution under acidic conditions to generate a precursor solution. Further, the dispersion liquid containing the antibacterial fine particles 22 described above, for example, the copper fine particle dispersion liquid is diluted with propylene glycol or the like to generate a fine particle dispersion liquid. Then, the precursor liquid and the fine particle dispersion liquid are mixed to generate a coating liquid for an antibacterial film. The concentration of the antibacterial fine particles 22 in this coating liquid is preferably, for example, 100 to 8000 ppm, more preferably 500 to 5000 ppm. If the concentration of the antibacterial fine particles 22 is too high, the visible light transmittance of the cover member 10 may decrease and the haze may increase. On the other hand, if the concentration of the antibacterial fine particles 22 is too low, the antibacterial function may not be exhibited.

Next, apply the coating liquid to the first surface of the washed glass plate 1. The coating method is not particularly limited, and for example, a flow coating method, a spray coating method, a spin coating method, or the like can be adopted. Then, the applied coating liquid is dried in an oven or the like at a predetermined temperature (for example, 80 to 120 ° C.) in order to volatilize the alcohol content in the solution, and then, for example, for hydrolysis and decomposition of organic chains. The antibacterial film 2 can be obtained by sintering at a predetermined temperature (for example, 200 to 500 ° C.).

<3. Optical characteristics of cover member>
As the optical characteristics of the cover member 10 on which the antibacterial film 2 is formed as described above, for example, the visible light transmittance is preferably 85% or more, and more preferably 90% or more. The haze rate of the cover member 10 is, for example, 20% or less, further 15% or less, particularly 10% or less, and in some cases, 1 to 8%, further 1 to 6%.

In addition, the gloss can be evaluated by the mirror glossiness. The 60 ° mirror gloss of the cover member 10 is, for example, 60 to 130%, further 70 to 120%, and particularly 80 to 110%. These mirror glossiness are values measured for the surface on which the antibacterial film 2 is formed. As a cover member for a display of an in-vehicle device such as a car navigation system, a member having a gloss of 120 to 140% is generally used.

It is preferable that the relational expression (a) is established between the 60 ° mirror glossiness G and the haze rate H (%), and it is more preferable that the relational expression (b) is established.
H ≦ -0.2G + 25 (a)
H ≦ -0.2G + 24.5 (b)

Gloss can be measured according to "Method 3 (60 degree mirror gloss)" of "Mirror gloss measuring method" of JIS Z8741-1997, and haze can be measured according to JIS K7136: 2000.

<4. Features>
The cover member 10 according to the present embodiment can exert the following effects. That is, unevenness is formed on the first surface of the glass plate 1, and an antibacterial film 2 having a holding layer 21 and antibacterial fine particles 22 is formed on the first surface. Therefore, the surface of the holding layer 21 is also formed with irregularities along the irregularities of the glass plate 1, whereby the antiglare function is exhibited. Further, since the antibacterial film 2 contains antibacterial fine particles 22 having an average particle size larger than the maximum thickness of the holding layer 21, the antibacterial fine particles 22 are arranged so as to protrude from the holding layer 21. As a result, the antibacterial function is exhibited. As described above, the antibacterial film 2 of the cover member 1 according to the present embodiment can have both an antiglare function and an antibacterial function at the same time.

<5. Modification example>
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. The following modifications can be combined as appropriate.

<5-1>
In the above embodiment, the bottom surface of the glass plate 1 is etched to form irregularities, but the top surface can be etched to form irregularities in the same manner.

<5-2>
There are various methods for forming irregularities on the glass plate 1, and the etching is not limited to the above-mentioned etching. In addition, for example, a base layer having irregularities can be formed on any one surface of the glass plate 1. The base layer can be formed, for example, by a base layer formed of the same material as the holding layer 21 described above and fine particles held by the base layer.

The shape of the fine particles is not particularly limited, but is preferably spherical. The fine particles may be substantially composed of spherical particles. However, some of the fine particles may have a shape other than a spherical shape, for example, a flat plate shape. The fine particles may be composed of only spherical particles. Here, the spherical particles refer to particles having a ratio of the longest diameter to the shortest diameter passing through the center of gravity of 1 or more and 1.8 or less, particularly 1 or more and 1.5 or less, and the surface of which is formed of a curved surface. The average particle size of the spherical particles may be 5 nm to 200 nm, more 10 nm to 100 nm, and particularly 20 nm to 60 nm. The average particle size of the spherical particles is determined by the average of the individual particle sizes, specifically, the average value of the shortest diameter and the longest diameter described above, and the measurement is preferably 30 particles based on the SEM image. It is desirable to carry out for 50 particles. As described above, by using fine particles having an average particle size smaller than that of the antibacterial fine particles 22, it is possible to form irregularities as a base for forming an appropriate surface roughness Ra on the holding layer 21 of the antibacterial film 2. ..

The material constituting the fine particles is not particularly limited, but preferably contains a metal oxide, particularly silicon oxide. However, the metal oxide may contain, for example, an oxide of at least one metal element selected from the group consisting of Al, Ti, Zr, Ta, Nb, Nd, La, Ce and Sn.

Further, the fine particles may be phyllosilicate mineral particles. The phyllosilicate mineral contained in the phyllosilicate mineral particles is also called a layered silicate mineral. Examples of the phyllosilicate mineral include kaolin minerals such as kaolinite, dikite, nacrite, and haloysite, serpentine such as chrysotile, lizardite, and amesite, and octahedral smectites such as montmorillonite and biderite, saponite, hectrite, and soconite. 2 octahedral mica such as 3 octahedral smectite, vermiculite, paragonite, illite, seradonite, 3 octahedral mica such as gold mica, anite, lepidrite, 2 octahedral brittle mica such as margarite, clintite, 3 octahedral fragile mica such as anandite, 2 octahedral chlorite such as donbasite, 2.3 octahedral chlorite such as cucumberite and sudowite, 3 octahedral chlorite such as clinochlorite and chamosite, pyrophylli Examples include light, talc, 2 octahedral vermiculite, and 3 octahedral vermiculite. The phyllosilicate mineral particles preferably contain minerals belonging to smectite, kaolin, or talc. As the mineral belonging to smectite, montmorillonite is suitable. In addition, montmorillonite belongs to the monoclinic system, kaolin belongs to the triclinic system, and talc belongs to the monoclinic system or the triclinic system.

Such an underlayer can be formed in the same manner as the above-mentioned antibacterial film. That is, the precursor liquid and the fine particle dispersion liquid as described above are mixed to generate a coating liquid for a base layer, which is applied to the surface of a glass plate and then sintered to form a base layer having irregularities on the surface. Can be formed. The surface roughness Ra of the base layer can be the same as the surface roughness Ra of the first surface of the glass plate 1 described above. Further, since such a base layer can be formed of the same material as the holding layer 21 of the antibacterial film 2, the refractive index of the base layer and the antibacterial film 2 can be brought close to each other. Therefore, the antiglare function can be exhibited more effectively.

In this case, for example, a glass plate (float glass) formed by the float method can be chemically strengthened to form a base layer with respect to the top surface. When the float glass is chemically strengthened, the top surface having a high concentration of sodium ions is exchanged with alkaline ions such as potassium ions more than the bottom surface, so that the top surface is easily warped so as to be convex. Therefore, when the above-mentioned base layer is formed on the top surface, the laminated base layer shrinks and the warp is alleviated. Therefore, from the viewpoint of suppressing warpage, it is preferable to form a base layer on the top surface of the chemically strengthened glass plate.

Further, a known antireflection film can be arranged between the base layer and the antibacterial film 2.

The material constituting the base layer of the base layer described above is an example, and can be appropriately changed. For example, the base layer can be formed of a material containing silicon oxide as a main component, but is not limited thereto. If silicon oxide is used as the main component, the refractive index (reflectance) of the base layer tends to be low. In addition, the chemical stability of the base layer is also good. In addition, the adhesion with the glass plate 1 is good. Here, the fact that silicon oxide is the main component means that SiO ₂ is contained in an amount of 50% by mass or more, but it is preferably contained in an amount of 90% by mass or more.

When silicon oxide is the main component, the base layer may be composed of only silicon oxide, or may contain a small amount of components other than silicon oxide. The components include Li, B, C, N, F, Na, Mg, Al, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Sr. , Y, Zr, Nb, Ru, Pd, Ag, In, Sn, Hf, Ta, W, Pt, Au, Bi and compounds such as one or more ions and / or oxides selected from lanthanoid elements. ..

The base layer containing silicon oxide as a main component includes those formed from a coating composition containing a silicon oxide precursor, those formed from a coating composition containing silicon oxide particles as particles, and other components not containing silicon oxide as a main component. Examples thereof include those formed by a resin film or the like.

<5-3>
The composition of the holding layer 21 is not particularly limited, and as described above, any material may be used as long as it has a predetermined surface roughness on the surface and can hold the antibacterial fine particles 22.

<5-4>
A fingerprint resistant layer can also be formed on the surface of the antibacterial film 2. By forming the fingerprint-resistant film, the swipe operation on the cover member 10 becomes easy, and the stains such as fingerprints become easy to wipe off.

The fingerprint resistant film can be formed, for example, as follows. The fingerprint-resistant film can have hydrophobic properties and sparse oil properties, that is, both sparse medium properties, so as to minimize the wetting of the cover member 10 by water and oil. Therefore, the wetting properties of a surface with a fingerprint resistant film are not only hydrophobic, i.e., the contact angle between the surface and water is preferably greater than 90 °, but also oleophobic, i.e., surface and oil. The contact angle between and should be preferably greater than 50 °.

The fingerprint-resistant film can be, for example, a film containing a silane containing an alkyl group and / or a fluoroalkyl group, for example, 3,3,3-trifluoropropyltrimethoxysilane or pentylriethoxysilane.

The fingerprint resistant film is based on a compound having a hydrocarbon group, even if the CH bond is a fluoro-based surface layer in which the CH bond is partially or preferably substantially entirely replaced by the CF bond. good. Preferably, such compounds are represented, for example, in formula (RF) _n SiX _4-n , where RF is _C ₁ to _C ₂₂ -alkyl perfluorohydrocarbons or -alkyl perfluoropolyethers, preferably. C ₁ to C ₁₀ -alkyl perfluorohydrocarbons or -alkyl perfluoropolyethers, where n is an integer of 1 to 3 and X is a hydrolyzable group such as a halogen or alkoxy group-OR (where R). Can be, for example, a linear or branched, perfluorohydrocarbon (representing a hydrocarbon having 1 to 6 carbon atoms). In this case, the hydrolyzable group X can react, for example, with the terminal OH group of the coating on the glass substrate and thus be attached to this group by the formation of a covalent bond. Perfluorohydrocarbons are preferably used to reduce the surface energy of the surface due to the low polarity of the fluorine surface bonds at the ends.

The fingerprint resistant film can be derived, for example, from a single layer of molecular chains with a fluorine end group, a fluoropolymer coating, or silicon oxide-suit particles pre-equipped with or treated with a fluorine end group. ..

The fingerprint-resistant film is preferably immersed, vapor-deposited, sprayed, applied with a roll or roller or blade, vacuum-deposited by heat or sputtered, preferably by liquid phase methods such as spraying, immersion coating, printing, roller coating, spin coating. Alternatively, it can be applied to the surface by other suitable methods. Immersion or spraying is particularly preferred. After applying the coating, it is advantageously cured over a suitable period of time and in a suitable time.

The thickness of the fingerprint-resistant film can be, for example, 50 to 1000 nm. If the thickness of the fingerprint-resistant film is too large, the antibacterial performance may be suppressed. On the other hand, if the thickness of the fingerprint-resistant film is too small, the fingerprint-resistant performance may be reduced.

The fingerprint-resistant film can be formed on the entire surface of the antibacterial film 2, but it can also be formed on a part of the antibacterial film 2. For example, when a part of the cover member 10 is arranged on a protected member 100 such as a keyboard that performs a key touch operation, a fingerprint resistant film is not formed on the key, and another swipe operation is performed, for example. The fingerprint-resistant layer can be formed only in the area to be covered.

<5-5>
A mask layer can be formed on a part of the glass plate 1 so that the protected member 100 cannot be seen from the outside in the portion where the mask layer is formed. For example, a mask layer can be formed on the peripheral edge of the glass plate 1 so that the protected member 100 cannot be seen from the outside on the peripheral edge of the cover member 10. As a result, for example, parts such as wiring and brackets of the protected member 100 can be hidden from the outside. The material of the mask layer may be appropriately selected according to the embodiment as long as it can shield the field of view from the outside, and for example, dark ceramics such as black, brown, gray, and navy blue may be used. In addition, a sheet material can be attached.

When black ceramic is selected as the material of the mask layer, for example, black ceramic is laminated on the surface of the cover member 10 opposite to the surface on which the antibacterial film 2 is formed by screen printing or the like, and glass is used. Heat the ceramic laminated together with the plate. Then, when the ceramic is cured, the mask layer is completed. As the ceramic used for the mask layer, various materials can be used. For example, the ceramic having the composition shown in Table 1 below can be used for the mask layer.

* 1, Main component: Copper oxide, Chromium oxide, Iron oxide and Manganese oxide * 2, Main component: Bismuth borosilicate, Zinc borosilicate

<5-6>
In addition to being colorless and transparent, the cover member according to the present invention can be colored transparent or translucent by coloring at least one of a glass plate 1, an antibacterial film 2, and an underlayer.

Hereinafter, examples of the present invention will be described. However, the present invention is not limited to the following examples.

(1) Preparation of Example A cover member according to Example 1 was formed by laminating a base layer on a float glass plate of 50 mm x 50 mm and further laminating an antibacterial film.

(1-1) Underlayer A precursor solution of the underlayer having the following composition was prepared (unit is g). Kaolin (phyllosilicate mineral particles) was used as the fine particles contained in the base layer. Then, these mixed solutions were stirred at 60 ° C. for 7 hours to obtain a precursor solution.

Nitric acid and kaolin TS90 are dissolved in Cleansolve P-7 manufactured by Japan Alcohol Trading Co., Ltd. Cleansolve P-7 is a mixed solvent containing ethanol as a main component, isopropyl alcohol, and normal propyl alcohol.

The precursor liquid was applied to the glass plate by flow coating, and then dried in an oven set at 200 ° C. to form an underlayer.

(1-2) Retention layer A precursor solution for a retention layer having the following composition was prepared (unit is g). Then, these mixed solutions were stirred at 60 ° C. for 7 hours, and a precursor solution was obtained by a hydrolysis reaction of TEOS.

A coating solution for an antibacterial film having the following composition was prepared for this precursor solution (unit: g). Copper was used as the antibacterial fine particles, and a dispersion diluted with propylene glycol to a concentration of 1% was prepared. Then, the materials in Table 4 were mixed while stirring in the order from top to bottom. Then, this mixed solution was stirred at room temperature to obtain a coating liquid.

Then, this coating liquid was applied onto the base layer by roll coating, air-dried for 10 minutes, and then heated in an oven set at 300 ° C. for 30 minutes to form an antibacterial film. In this way, the cover member according to this embodiment was completed. The following tests were performed on this cover member.

(2) Optical characteristics The gloss was 119.2. Therefore, sufficient anti-glare performance can be exhibited. The haze rate was 3.2%, which was sufficiently low. The haze rate was measured by a haze meter NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd. At this time, the antibacterial film was used as the incident surface, the haze rate was measured at three points of the sample, and the average value was taken as the haze rate.

(3) Surface roughness The surface roughness Ra of the antibacterial film was 52 nm. The average length Rsm of the roughness curve element of the antibacterial film was 16.2 μm.

(4) Antibacterial test The antibacterial property was evaluated based on JIS Z2801: 2012 (film adhesion method) as follows (corresponding to ISO22216).
-Test bacteria: E. Coli (E. coli NBRC3972)
-Sample form: The cover member-Action time: 24 hours-Calculation of antibacterial activity value (R): R = (Ut-U0)-(At-U0) = Ut-At
U0: Mean of log of viable cell count immediately after inoculation of glass plate Ut: Mean of log of viable cell count after 24 hours of glass plate At: Log of viable cell count after 24 hours of cover member Mean value / working conditions: Temperature 35 ° C, humidity 90% or more (JIS compliant)
-Adhesion film: 40 mm x 40 mm PP film (JIS standard)
・ Intake of test bacterial solution: 0.2 ml
・ Viable cell count of test bacterial solution: 1.1 × 10 ⁶
・ Measurement of viable cell count: Measure the viable cell count of the cover member immediately after inoculation of the bacterial solution on the glass plate and after culturing for 24 hours.

As a result of the above test, the antibacterial activity was 6.1. Since it is evaluated to have antibacterial activity at 2.0 or higher, sufficient antibacterial performance was confirmed in this example.

(5) Antiviral test The antiviral property was evaluated according to ISO21702 as follows.
-Host cell: MDCK cell (ATCC CCL-34)
-Sample form: The cover member-Action time: 24 hours-Calculation of antiviral activity value (R): R = (Ut-U0)-(At-U0) = Ut-At
U0: Average logarithmic number of plaques immediately after inoculation of the glass plate, PFU / cm ²
Ut: Average logarithmic number of plaques after 24 hours on the glass plate, PFU / cm ²
At: Average logarithmic number of plaques after 24 hours of cover member, PFU / cm ²
-Operating conditions: Temperature 25 ° C
-Adhesion film: 40 mm x 40 mm PP film (ISO standard)
・ Intake of test virus solution: 0.4 ml
・ Infectious titer of test virus solution: 1.5 × 10 ⁷ PFU / ml
・ Measurement method of viral load: plaque method

As a result of the above test, the antiviral activity was 1.6. As a result, it is judged that the virus is reduced by about 97% as compared with the glass plate on which the antibacterial film is not formed.

(6) Surface properties FIG. 3 is a photograph of the surface texture of the antibacterial film of the example observed by SEM, and FIG. 4 is an enlarged view of the antibacterial fine particles shown in the photograph of FIG. A plurality of white dots shown in FIG. 3 indicate antibacterial fine particles. Further, as shown in FIG. 4, it can be seen that the antibacterial fine particles according to this example are aggregates of copper particles. The particle size of the antibacterial fine particles shown in FIG. 3 was 1 to 4 μm. The maximum distance between the antibacterial fine particles was 50 μm, the minimum was 5 μm, and the average was 25 μm.

The average particle size was calculated by the following method. First, three SEM images with a magnification of 1000 times were acquired in different fields of view. Next, the following measurement was performed in the range of 90 μmx 120 μm (the range surrounded by the broken line in FIG. 3). First, the length in the major axis direction and the length in the minor axis direction of the antibacterial fine particles are measured, and the average of them is taken as the particle size of one antibacterial fine particle. Then, the same measurement was performed for any antibacterial fine particles at 10 points per image, for a total of 30 points, and the average of them was taken as the average particle size.

The distance between the antibacterial fine particles was calculated as follows. First, three SEM images with a magnification of 1000 times were acquired in different fields of view. Next, the spacing between arbitrary adjacent antibacterial fine particles was measured. The same measurement was performed for any 10 sets of antibacterial fine particles at 10 points per image, for a total of 30 points, and the average of them was taken as the distance between the antibacterial fine particles.

1 Glass plate 2 Antibacterial film 21 Retaining layer 22 Antibacterial fine particles 10 Cover member 100 Protected member

Claims

A plate-shaped base material having a first surface and a second surface, the first surface having a predetermined surface roughness,
The antibacterial film formed on the first surface and
Equipped with
The antibacterial membrane is
The holding layer formed on the first surface and
A cover member comprising: antibacterial fine particles held by the holding layer and having an average particle size equal to or larger than the film thickness of the holding layer.
The cover member according to claim 1, wherein the surface roughness of the holding layer is smaller than the surface roughness of the first surface of the base material and smaller than 120 nm.
The cover member according to claim 1 or 2, wherein the maximum film thickness of the holding layer is smaller than the surface roughness of the base material.
The cover member according to any one of claims 1 to 3, wherein the holding layer of the antibacterial film contains silicon oxide as a main component.
The cover member according to any one of claims 1 to 4, wherein the base material is formed of a glass plate having the first surface and the second surface.
The cover member according to claim 5, wherein the glass plate is formed of float glass, and the bottom surface of the float glass constitutes the first surface.
The cover member according to any one of claims 1 to 4, wherein the base material comprises a glass plate and a base layer formed on one surface of the glass plate and having the predetermined surface roughness. ..
The cover member according to claim 7, wherein the base layer includes a base layer containing silicon oxide as a main component and fine particles held in the base layer.
The cover member according to claim 7 or 8, wherein the glass plate is formed of float glass, and the base layer is formed on the top surface of the float glass.
The cover member according to any one of claims 5 to 9, wherein the thickness of the glass plate is 3 mm or less.
The cover member according to claim 10, wherein the average particle size of the fine particles is smaller than the average particle size of the antibacterial fine particles.
The cover member according to any one of claims 1 to 11, wherein the distance between the antibacterial fine particles on the holding layer is 1 to 200 μm.
The cover member according to any one of claims 1 to 12, wherein the average particle size of the antibacterial fine particles is 0.1 to 10 μm.
The cover member according to any one of claims 1 to 13, wherein a fingerprint-resistant layer formed on at least a part of the antibacterial film is formed.
The cover member according to claim 14, wherein the fingerprint-resistant layer has a thinner film thickness than the antibacterial film.
The cover member according to claim 14 or 15, wherein the fingerprint-resistant layer is formed on a part of the antibacterial film.
The cover member according to any one of claims 1 to 16, wherein the antibacterial fine particles are made of copper.
The cover member according to any one of claims 1 to 17, further comprising an antireflection film arranged between the base material and the antibacterial film.
The cover member according to any one of claims 1 to 18, which is arranged so as to cover the surface of a display, a keyboard, or an electronic blackboard.