阅读说明：本技术 带有凹凸形状的玻璃基体及其制造方法 (Glass substrate with concave-convex shape and manufacturing method thereof ) 是由 赤间佑纪 留野晓 于 2020-02-26 设计创作，主要内容包括：本发明涉及带有凹凸形状的玻璃基体及其制造方法。本发明涉及一种带有凹凸形状的玻璃基体的制造方法,其中,进行使玻璃基体与磨砂处理液接触1分钟以上的磨砂处理,所述磨砂处理液含有1.8质量％以上的氟化氢、并且含有氟化钾,所述氟化氢的质量％浓度相对于所述氟化钾的质量％浓度之比为0.5以上且1.5以下,并且以氧化物基准的质量％表示,所述玻璃基体含有：50质量％～75质量％的SiO<Sub>2</Sub>、10质量％～25质量％的Al<Sub>2</Sub>O<Sub>3</Sub>、和2质量％～6质量％的Li<Sub>2</Sub>O。(The present invention relates to a glass substrate having a concavo-convex shape and a method for manufacturing the same. The present invention relates to a method for producing a glass substrate having an uneven shape, wherein a glass substrate is subjected to a polishing treatment for 1 minute or more by bringing the glass substrate into contact with a polishing treatment liquidA sand treatment, wherein the abrasive treatment liquid contains 1.8 mass% or more of hydrogen fluoride and contains potassium fluoride, the ratio of the mass% concentration of the hydrogen fluoride to the mass% concentration of the potassium fluoride is 0.5 or more and 1.5 or less, and the glass substrate contains, in terms of mass% on an oxide basis: 50 to 75 mass% of SiO 2 10 to 25 mass% of Al 2 O 3 And 2 to 6 mass% of Li 2 O。)

1. A method for producing a glass substrate having an uneven shape, wherein a polishing treatment is performed by bringing the glass substrate into contact with a polishing treatment liquid containing 1.8 mass% or more of hydrogen fluoride and potassium fluoride for 1 minute or more, the ratio of the mass% concentration of the hydrogen fluoride to the mass% concentration of the potassium fluoride is 0.5 to 1.5, and the polishing treatment liquid is characterized in that the polishing treatment liquid contains potassium fluoride and hydrogen fluoride

The glass matrix contains, in mass% on an oxide basis:

50 to 75 mass% of SiO₂、

10 to 25 mass% of Al₂O₃And, and

2 to 6 mass% of Li₂O。

2. The method for producing a glass substrate with an irregular shape according to claim 1, wherein after the frosting treatment, a shape adjustment treatment is further performed in which the glass substrate is brought into contact with a shape adjustment liquid containing 3.0 mass% to 6.0 mass% of hydrogen fluoride for 1 minute or more.

3. The method for producing a glass substrate with a textured shape according to claim 1 or 2, wherein the concentration of potassium fluoride in mass% of the abrasive treatment liquid is relative to Li of the glass substrate expressed by mass% on an oxide basis₂The ratio of the O content is 0.3 to 3.5, and the mass% concentration of the hydrogen fluoride in the polishing liquid is relative to Li of the glass substrate expressed by mass% based on oxides₂The ratio of the O content is 0.3 to 2.5.

4. The method for producing a glass substrate having a textured shape according to claim 2, wherein the shape-regulating liquid further contains 5.0 mass% to 15.0 mass% of hydrogen chloride.

5. The method for producing a glass substrate with an irregular shape according to claim 2 or 4, wherein after the shape adjustment treatment, a chemical strengthening treatment is further performed in which the glass substrate is brought into contact with an inorganic salt containing at least one of sodium nitrate and potassium nitrate to perform ion exchange.

6. The method for manufacturing a glass substrate with a textured shape according to claim 5, wherein the chemical strengthening treatment is performed 2 times or more.

7. The method for producing a glass substrate with a textured shape according to claim 1 or 2, wherein the glass substrate contains, in mass% on an oxide basis:

50 to 75 mass% of SiO₂、

10 to 25 mass% of Al₂O₃、

2 to 6 mass% of Li₂O、

0 to 18 mass% of Na₂O、

0 to 10 mass% of K₂O、

0 to 10 mass% of MgO,

0 to 5 mass% of CaO,

0 to 15 mass% of P₂O₅、

0 to 5 mass% of Y₂O₃And, and

0 to 5 mass% of ZrO₂。

8. A method for producing a glass substrate having an uneven shape, wherein a polishing treatment is performed by bringing the glass substrate into contact with a polishing treatment liquid containing 15.0 mass% or more of hydrogen fluoride and ammonium fluoride for 1 minute or more, the ratio of the mass% concentration of the hydrogen fluoride to the mass% concentration of the ammonium fluoride is 1.0 or less,

after the frosting treatment, a shape-adjusting treatment is performed by bringing the glass substrate into contact with a shape-adjusting liquid containing 3.0 to 6.0 mass% of hydrogen fluoride and containing hydrogen fluoride for 1 minute or more

The glass matrix contains, in mass% on an oxide basis:

50 to 75 mass% of SiO₂、

10 to 25 mass% of Al₂O₃And, and

2 to 6 mass% of Li₂O。

9. The method for manufacturing a glass substrate with a textured shape according to claim 8, wherein the concentration of ammonium fluoride in mass% in the abrasive treatment liquid is relative to Li of the glass substrate expressed by mass% based on an oxide₂The ratio of the O content is 4.0 to 5.5 inclusive, and the mass% concentration of the hydrogen fluoride in the polishing liquid is based on Li in the glass substrate expressed by mass% based on oxides₂The ratio of the O content is 3.5 to 5.0.

10. The method for producing a glass substrate having an irregular shape according to claim 8 or 9, wherein the shape-regulating liquid further contains 5.0 mass% or more and 15.0 mass% or less of hydrogen chloride.

11. The method for manufacturing a glass substrate with an irregular shape according to claim 8 or 9, wherein after the shape adjustment treatment, a chemical strengthening treatment is further performed in which the glass substrate is brought into contact with an inorganic salt containing at least one of sodium nitrate and potassium nitrate to perform ion exchange.

12. The method for manufacturing a glass substrate with a textured shape according to claim 11, wherein the chemical strengthening treatment is performed 2 times or more.

13. The method for producing a glass substrate with a textured shape according to claim 8 or 9, wherein the glass substrate contains, in mass% on an oxide basis:

50 to 75 mass% of SiO₂、

10 to 25 mass% of Al₂O₃、

2 to 6 mass% of Li₂O、

0 to 18 mass% of Na₂O、

0 to 10 mass% of K₂O、

0 to 10 mass% of MgO,

0 to 5 mass% of CaO,

0 to 15 mass% of P₂O₅、

0 to 5 mass% of Y₂O₃And, and

0 to 5 mass% of ZrO₂。

14. A glass substrate with a concavo-convex shape, wherein the glass substrate with the concavo-convex shape has one main surface and the other main surface, and the concavo-convex shape is formed on at least one main surface,

the glass substrate with an uneven shape contains, in mass% based on oxides:

50 to 75 mass% of SiO₂、

10 to 25 mass% of Al₂O₃And, and

2 to 6 mass% of Li₂O, and

the portion having the uneven shape has a haze of 45% or more and a glossiness of 25 or less.

15. The glass substrate with a textured shape according to claim 14, wherein the haze is 90% or less and the gloss is 5 or more.

16. The glass substrate with an uneven shape according to claim 14 or 15, wherein a surface roughness Ra of a portion where the uneven shape is formed is 0.1 μm to 4.0 μm.

17. The glass substrate with an uneven shape according to claim 14 or 15, wherein the glass substrate with an uneven shape is chemically strengthened glass having a surface compressive stress value of 300MPa or more and a compressive stress layer depth of 10 μm or more.

Technical Field

The present invention relates to a glass substrate having a concavo-convex shape and a method for manufacturing the same.

Background

As a method for improving the impact resistance of a cover glass disposed on the display surface of an image display device, a chemical strengthening treatment is known in which a glass substrate used as a cover glass is brought into contact with an inorganic salt to perform ion exchange.

Recently, as a method for further improving impact resistance, the inclusion of Li has been proposed₂The glass substrate of O is subjected to chemical strengthening treatment by ion exchange twice (patent document 1).

Incidentally, in recent years, with the spread of mobile devices having an image display device such as a mobile phone and a tablet personal computer terminal, research and development have been conducted not only on protective glass disposed on a display surface of the image display device but also on rear protective glass disposed on a rear surface opposite to the display surface.

A back cover glass disposed on the back side of an image display device is sometimes required to have excellent aesthetic properties as required characteristics in addition to mechanical strength such as impact resistance. Therefore, a glass substrate used as a back cover glass may be subjected to a decoration treatment on a main surface on the side which becomes an exposed surface when used. As the decorative treatment, an antiglare treatment for reducing the glossy feeling of glass to have a mat surface is particularly desired.

As the antiglare treatment, an etching antiglare (etching AG) treatment is known in which an uneven shape is formed on the surface of a glass substrate to diffusely reflect light (patent document 2).

Disclosure of Invention

Problems to be solved by the invention

The cover glass described in patent document 2 does not contain Li as a glass composition₂And O. Therefore, it is not clear whether the etching AG treatment described in patent document 2 can be applied to Li-containing etching₂O glass.

The present inventors applied the etching AG treatment described in patent document 2 to Li-containing glass in order to produce a back cover glass having excellent impact resistance and excellent appearance₂A glass substrate of O. As a result, the present inventors found that: sometimes, the haze is not high or the gloss is not low, and the appearance is not excellent.

Accordingly, it is an object of the present invention to provide a lithium-containing lithium compound₂O-shaped glass substrate with concave-convex shape and excellent aesthetic property and a manufacturing method thereof.

Means for solving the problems

The present inventors have conducted intensive studies to solve the above problems, and as a result, have completed the present invention.

That is, a first aspect of the present invention is a method for producing a glass substrate having an uneven shape, in which a polishing treatment is performed by bringing the glass substrate into contact with a polishing treatment liquid containing 1.8 mass% or more of hydrogen fluoride and potassium fluoride for 1 minute or more, a ratio of a mass% concentration of the hydrogen fluoride to a mass% concentration of the potassium fluoride is 0.5 to 1.5, and the glass substrate contains 50 to 75 mass% of SiO in terms of mass% on an oxide basis₂10 to 25 mass% of Al₂O₃And 2 to 6 mass% of Li₂O。

A second aspect of the present invention is a method for producing a glass substrate having an uneven shape, wherein a polishing treatment is performed by bringing a glass substrate into contact with a polishing treatment liquid containing 15.0 mass% or more of hydrogen fluoride and ammonium fluoride for 1 minute or more, a ratio of a mass% concentration of the hydrogen fluoride to a mass% concentration of the ammonium fluoride is 1.0 or less, and a shape adjustment treatment is performed by bringing the glass substrate into contact with a shape adjustment liquid containing 3.0 mass% or more and 6.0 mass% or less of hydrogen fluoride and containing 50 to 75 mass% of SiO, expressed in terms of mass% on an oxide basis, for 1 minute or more after the polishing treatment, and the glass substrate is brought into contact with the shape adjustment liquid for 1 minute or more₂10 to 25 mass%Al₂O₃And 2 to 6 mass% of Li₂O。

In addition, a third aspect of the present invention is a glass substrate with an uneven shape, wherein the glass substrate with an uneven shape has one main surface and the other main surface, and an uneven shape is formed on at least one main surface, and the glass substrate with an uneven shape contains 50 to 75 mass% of SiO, expressed in mass% based on oxides, of 50 to 75 mass%₂10 to 25 mass% of Al₂O₃And 2 to 6 mass% of Li₂And O, wherein the haze of the portion having the uneven shape is 45% or more and the glossiness is 25 or less.

Effects of the invention

According to the present invention, there can be provided a lithium-containing compound₂O-shaped glass substrate with concave-convex shape and excellent aesthetic property and a manufacturing method thereof.

Detailed Description

[ first mode ]

A first aspect of the present invention is a method for producing a glass substrate having an uneven shape, wherein a polishing treatment is performed by bringing the glass substrate into contact with a polishing treatment liquid containing 1.8 mass% or more of hydrogen fluoride and potassium fluoride for 1 minute or more, the ratio of the mass% concentration of the hydrogen fluoride to the mass% concentration of the potassium fluoride is 0.5 to 1.5, and the glass substrate contains 50 to 75 mass% of SiO in terms of mass% on an oxide basis₂10 to 25 mass% of Al₂O₃And 2 to 6 mass% of Li₂O。

According to the above method, it is presumed that Li is contained even in the following mechanism₂The glass substrate of O also becomes a glass substrate having high haze and low gloss (hereinafter, also simply referred to as "high haze").

First, hydrogen fluoride is used to etch the glass substrate to generate SiF₆The function of the ions. When the concentration of hydrogen fluoride is not less than the above range, SiF can be produced in a sufficient amount₆Ions. Potassium fluoride has the same structure as SiF₆The ions react to produce K as a precipitated salt₂SiF₆The function of (c). When the concentration of potassium fluoride is in the above range, it is possible to react with SiF produced from hydrogen fluoride₆The ions react in a proper amount, the nucleation density of the precipitated salt in the surface of the glass matrix is proper, and the precipitated salt can be formed uniformly.

Preferably, after the frosting treatment, the glass substrate is further subjected to a shape adjustment treatment in which the glass substrate is brought into contact with a shape adjustment liquid containing 3.0 mass% to 6.0 mass% of hydrogen fluoride for 1 minute or more. By adjusting the surface shape of the glass substrate by performing this treatment, the effect of easily adjusting the haze and the gloss to appropriate values can be obtained.

Further, it is preferable that the concentration of potassium fluoride in the polishing liquid is set to be equal to Li in mass% based on oxide in the glass matrix₂The ratio of the O content is 0.3 to 3.5, and the mass% concentration of the hydrogen fluoride in the polishing liquid is relative to Li of the glass substrate expressed by mass% based on oxides₂The ratio of the O content is 0.3 to 2.5. By adjusting the concentration of the potassium fluoride in the polishing liquid to Li of the glass matrix₂The ratio of the O content and the concentration of the hydrogen fluoride with respect to Li of the glass matrix₂When the ratio of the O content is set within this range, the effect of obtaining a highly hazy uneven shape can be obtained more effectively by the following mechanism.

I.e. in the presence of Li₂O in the glass matrix, except for the precipitated salt K derived from the hydrogen fluoride and the potassium fluoride₂SiF₆In addition, LiF is precipitated. The Li ions of LiF are generated from the glass matrix, which is similar to the K ions described above₂SiF₆Different. Thus, two kinds of precipitates having different causes are simultaneously precipitated in the plane of the glass substrate.

Therefore, according to the above potassium fluoride, the above hydrogen fluoride and Li in the glass matrix₂The amount of O varies depending on the ratio of precipitated salt and the density of formation. By setting the ratio of the above three within the above range, salt is precipitatedThe glass substrate having a higher haze can be obtained by producing a glass substrate having an appropriate and uniform density.

Preferably, the shape-regulating liquid further contains 5.0 mass% to 15.0 mass% of hydrogen chloride. This can provide an effect of dissolving the salt precipitated on the surface of the glass substrate and increasing the etching rate, and also can provide an effect of increasing the liquid life of the shape-regulating liquid.

Preferably, after the shape adjustment treatment, the glass substrate is further subjected to a chemical strengthening treatment for ion exchange by contacting the glass substrate with an inorganic salt containing at least one of sodium nitrate and potassium nitrate. By performing the chemical strengthening treatment, a high-strength glass substrate can be obtained.

The chemical strengthening treatment is preferably performed 2 times or more. By performing the chemical strengthening treatment 2 times or more, a glass substrate having more excellent impact resistance can be obtained.

The glass substrate preferably contains, in mass% on an oxide basis:

50 to 75 mass% of SiO₂、

10 to 25 mass% of Al₂O₃、

2 to 6 mass% of Li₂O、

0 to 18 mass% of Na₂O、

0 to 10 mass% of K₂O、

0 to 10 mass% of MgO,

0 to 5 mass% of CaO,

0 to 15 mass% of P₂O₅、

0 to 5 mass% of Y₂O₃And, and

0 to 5 mass% of ZrO₂。

[ second mode ]

A second aspect of the present invention is a method for producing a glass substrate having an uneven shape, wherein a frosting is performed by bringing the glass substrate into contact with a frosting treatment liquid for 1 minute or moreA treatment in which the polishing liquid contains 15.0 mass% or more of hydrogen fluoride and ammonium fluoride, the ratio of the mass% concentration of the hydrogen fluoride to the mass% concentration of the ammonium fluoride is 1.0 or less, and after the polishing treatment, a shape adjustment treatment is performed in which the glass substrate is brought into contact with a shape adjustment liquid for 1 minute or more, the shape adjustment liquid containing 3.0 mass% or more and 6.0 mass% or less of hydrogen fluoride and containing 50 to 75 mass% of SiO, expressed in terms of mass% based on oxides, the glass substrate containing 50 to 75 mass% of SiO₂10 to 25 mass% of Al₂O₃And 2 to 6 mass% of Li₂O。

According to the above method, it is presumed that Li is contained in the alloy probably by the following mechanism₂The glass substrate of O also becomes a glass substrate of high haze.

First, ammonium fluoride is reacted with SiF produced by reacting hydrogen fluoride with a glass substrate₆Ion reaction to generate precipitated salt (NH) on the glass substrate₄)₂SiF₆. Since the solubility of the precipitated salt is high, it is necessary to make the precipitation reaction of the salt dominant over the etching reaction. When the concentration of ammonium fluoride is in the above range, it is possible to react with SiF produced from hydrogen fluoride₆The ions react in a proper amount, the nucleation density of the precipitated salt in the surface of the glass matrix is proper, and the precipitated salt can be formed uniformly.

Further, by performing the shape adjustment processing, the distribution of the uneven shape in the height direction is suppressed, and the in-plane uniformity is improved.

Preferably, the mass% concentration of the ammonium fluoride in the polishing liquid is relative to Li of the glass matrix expressed by mass% based on oxides₂The ratio of the O content is 4.0 to 5.5 inclusive, and the mass% concentration of the hydrogen fluoride in the polishing liquid is based on Li in the glass substrate expressed by mass% based on oxides₂The ratio of the O content is 3.5 to 5.0. By adjusting the concentration of the ammonium fluoride in the polishing liquid to Li of the glass matrix₂The ratio of the concentration of the O content to the concentration of the hydrogen fluoride with respect to the glass baseBulk Li₂When the ratio of the O content is set within this range, a glass substrate having a high haze can be more effectively obtained by the following mechanism.

I.e. in the presence of Li₂In the glass matrix of O, in addition to the precipitated salt (NH) derived from the above-mentioned hydrogen fluoride and the above-mentioned ammonium fluoride₄)₂SiF₆In addition, LiF is precipitated. The Li ions of LiF are generated from the glass matrix, which is similar to the above (NH)₄)₂SiF₆Different. Thus, two kinds of precipitates having different causes are simultaneously precipitated in the plane of the glass substrate.

Thus, according to the above ammonium fluoride, the above hydrogen fluoride and Li in the glass matrix₂The amount of O varies depending on the ratio of precipitated salt and the density of formation. When the ratio of the three is within the above range, the density of the precipitated salt is appropriately and uniformly formed, and thus a glass substrate having a higher haze can be obtained after contacting the shape-regulating liquid.

Preferably, the shape-regulating liquid further contains 5.0 mass% to 15.0 mass% of hydrogen chloride. This can provide an effect of dissolving the salt precipitated on the surface of the glass substrate and increasing the etching rate, and also can provide an effect of increasing the liquid life of the shape-regulating liquid.

Preferably, after the shape adjustment treatment, the glass substrate is further subjected to a chemical strengthening treatment for ion exchange by contacting the glass substrate with an inorganic salt containing at least one of sodium nitrate and potassium nitrate. By performing the chemical strengthening treatment, a high-strength glass substrate can be obtained.

The chemical strengthening treatment is preferably performed 2 times or more. By performing the chemical strengthening treatment 2 times or more, a glass substrate having more excellent impact resistance can be obtained.

The glass substrate preferably contains, in mass% on an oxide basis:

50 to 75 mass% of SiO₂、

10 to 25 mass% of Al₂O₃、

2 to 6 mass% of Li₂O、

0 to 18 mass% of Na₂O、

0 to 10 mass% of K₂O、

0 to 10 mass% of MgO,

0 to 5 mass% of CaO,

0 to 15 mass% of P₂O₅、

0 to 5 mass% of Y₂O₃And, and

0 to 5 mass% of ZrO₂。

[ third mode ]

A third aspect of the present invention is a glass substrate with an uneven shape, wherein the glass substrate with an uneven shape has one main surface and the other main surface, and an uneven shape is formed on at least one main surface, and the glass substrate with an uneven shape contains 50 to 75 mass% of SiO, expressed in mass% based on oxides₂10 to 25 mass% of Al₂O₃And 2 to 6 mass% of Li₂And O, wherein the haze of the portion having the uneven shape is 45% or more and the glossiness is 25 or less.

The glass substrate with the concave-convex shape of the above-described embodiment contains Li₂And a glass substrate having a rough surface and a rough surface, which is O-shaped and has a matte appearance.

In the glass substrate with an uneven shape according to the above aspect, the haze is preferably 90% or less, and the gloss is preferably 5 or more.

In the glass substrate with an uneven shape of the above-described aspect, it is preferable that the surface roughness Ra of the portion where the uneven shape is formed is 0.1 μm to 4.0 μm. In this case, an effect of increasing scattering of light can be obtained by forming a region having an appropriate inclination of the unevenness.

The glass substrate with an uneven shape of the above-described embodiment is preferably a chemically strengthened glass having a surface compressive stress value of 300MPa or more and a compressive stress layer depth of 10 μm or more. In this case, when the glass matrix is inadvertently dropped, the scratch resistance ( strength added) against an acute-angle colliding object having a small-angle collision portion such as sand is improved.

Next, embodiments of the present invention including the first and second embodiments (hereinafter also referred to as "the present embodiment") will be described in detail. Hereinafter, first, a description will be given of a glass substrate, and then, a description will be given of a method for producing a glass substrate in the order of respective processes.

[ glass substrate ]

The glass substrate of the present embodiment contains 50 to 75 mass% of SiO, expressed in mass% based on oxides₂10 to 25 mass% of Al₂O₃And 2 to 6 mass% of Li₂And O. Thus, by performing the chemical strengthening treatment described later, a high-strength glass can be obtained.

The glass substrate preferably contains, in mass% on an oxide basis: 50 to 75 mass% of SiO₂10 to 25 mass% of Al₂O₃2 to 6 mass% of Li₂O, 0 to 18 mass% of Na₂O, 0 to 10 mass% of K₂O, 0 to 10 mass% of MgO, 0 to 5 mass% of CaO, and 0 to 15 mass% of P₂O₅0 to 5 mass% of Y₂O₃And 0 to 5 mass% of ZrO₂。

The method for producing the glass substrate is not particularly limited. For example, it can be manufactured in the following manner: a desired glass raw material is charged into a continuous melting furnace, the glass raw material is heated and melted at preferably 1500 to 1600 ℃, the glass raw material is clarified and supplied to a forming apparatus, and then the molten glass is formed and slowly cooled.

Specific examples of the production method include: a downdraw method (e.g., an overflow downdraw method, a flow-hole downdraw method, and a redraw method), a float method, a roll method, a press method, and the like. In the float process, a flat glass substrate having a substantially uniform thickness and width can be formed by floating a molten glass base material on a molten metal such as tin and performing a severe temperature operation.

The glass substrate may have a bent portion.

The shape of the edge portion of the glass substrate is not particularly limited, and may be, for example, 2.5D or 3D. This can provide an effect of improving the strength of the end face.

[ frosting treatment ]

The frosting treatment is a treatment of bringing a frosting treatment liquid into contact with the surface of the glass substrate to form precipitated salts on the surface of the glass substrate and to etch the surface of the glass substrate. This enables the formation of an uneven shape on the surface of the glass substrate. The uneven shape of the surface of the glass substrate is mainly determined by the generation rate and generation density of the precipitated salt, and the etching rate. Therefore, the relationship between the composition of the glass matrix and the composition of the matte treatment liquid is important in determining the light scattering property, that is, the matting property (マット property).

In a first aspect, the polishing liquid contains Hydrogen Fluoride (HF) in an amount of 1.8 mass% or more and potassium fluoride (KF), and a ratio of a mass% concentration of the hydrogen fluoride to a mass% concentration of the potassium fluoride (HF/KF) is 0.5 to 1.5.

In the first aspect, the concentration of the Hydrogen Fluoride (HF) in the polishing liquid is preferably 1.9 mass% or more, and more preferably 2.0 mass% or more. By setting the concentration of hydrogen fluoride within this range, SiF as a counter ion of the cation source can be sufficiently supplied₆The ions easily and uniformly form precipitated salts on the surface of the glass substrate.

The upper limit of the concentration of hydrogen fluoride is not particularly limited, but is preferably 13.0% by mass or less, and more preferably 10.0% by mass or less.

In the first aspect, the ratio (HF/KF) in the polishing liquid is preferably 0.6 or more and 1.4 or less, and more preferably 0.7 or more and 1.3 or less. By setting the ratio within this range, the density of the precipitated salt is appropriate, and uniform high haze treatment in the surface is facilitated.

In a second aspect, the polishing liquid contains 15.0 mass% or more of Hydrogen Fluoride (HF), and ammonium fluoride (NH)₄F) A ratio of the mass% concentration of the hydrogen fluoride to the mass% concentration of the ammonium fluoride (HF/NH)₄F) Is 1.0 or less.

In the second aspect, the concentration of the Hydrogen Fluoride (HF) in the polishing liquid is preferably 16.5 mass% or more, and more preferably 18.0 mass% or more. By setting the concentration of hydrogen fluoride within this range, SiF as a precipitated salt source can be sufficiently produced on the surface of the glass substrate₆The effect of the ions.

The upper limit of the concentration of hydrogen fluoride is not particularly limited, but is preferably 30.0% by mass or less, and more preferably 28.0% by mass or less.

In a second aspect, the ratio (HF/NH) in the polishing liquid is₄F) Preferably 0.95 or less, more preferably 0.9 or less. When the ratio is within this range, NH as a precipitated salt source can be sufficiently generated on the surface of the glass substrate₄The effect of the ions.

The above ratio (HF/NH)₄F) The lower limit of (b) is not particularly limited, but is preferably 0.4 or more, and more preferably 0.5 or more.

The contact time of the frosted finish liquid with the glass substrate is 1 minute or more, preferably 2 minutes or more, and more preferably 3 minutes or more. By setting the contact time within this range, the effect of homogenizing the surface of the glass substrate can be obtained. The upper limit of the contact time is not particularly limited, but is preferably 15 minutes or less, and more preferably 10 minutes or less.

The temperature of the scrub treatment is not particularly limited, and is, for example, 15 ℃ to 30 ℃, preferably 17.5 ℃ to 27.5 ℃, and more preferably 20 ℃ to 25 ℃.

In the case of the first aspect of the present invention, it is preferable that the components of the polishing liquid and Li in the glass matrix are₂O shows a specific relationship.

Specifically, the matte treatment liquid has a concentration of potassium fluoride in mass% with respect to Li in the glass matrix₂Ratio of O content (KF/Li)₂O) is preferably 0.3 or more and3.5 or less, more preferably 0.35 or more and 3.4 or less, and still more preferably 0.4 or more and 3.3 or less.

Further, the mass% concentration of hydrogen fluoride in the polishing liquid is based on Li in the glass matrix₂Ratio of O content (HF/Li)₂O) is preferably 0.3 or more and 2.5 or less, more preferably 0.35 or more and 2.4 or less, and further preferably 0.4 or more and 2.3 or less.

In the case of the second aspect of the present invention, it is preferable that the components of the polishing liquid and Li in the glass matrix are₂O shows a specific relationship.

Specifically, the mass% concentration of ammonium fluoride in the polishing liquid is based on Li in the glass matrix₂Ratio of O content (NH)₄F/Li₂O) is preferably 4.0 or more and 5.5 or less, more preferably 4.2 or more and 5.45 or less, and further preferably 4.4 or more and 5.4 or less.

Further, the mass% concentration of hydrogen fluoride in the polishing liquid is based on Li in the glass matrix₂Ratio of O content (HF/Li)₂O) is preferably 3.5 or more and 5.0 or less, more preferably 3.6 or more and 4.9 or less, and further preferably 3.7 or more and 4.8 or less.

The polishing liquid may contain, in addition to the above components, a fluoride ion source, an inorganic acid, a buffer solution, or a combination thereof as necessary.

The fluoride ion source is, for example, a salt selected from ammonium fluoride, ammonium bifluoride, sodium fluoride, sodium hydrogen fluoride, potassium fluoride and potassium bifluoride, and the like, or a combination thereof.

Inorganic acids are for example hydrofluoric acid, sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid, and similar acids, or combinations thereof. In addition, a glycol, glycerol, alcohol, ketone, or surfactant, or a combination thereof may be further added.

After contacting with the polishing liquid, the glass substrate is preferably cleaned. By removing the precipitated salt from the surface of the glass substrate by washing, the shape adjustment treatment of the subsequent step can be easily performed uniformly over the entire surface of the glass substrate.

The cleaning liquid used for cleaning is preferably pure water. Further, brushing is preferable. This enables the precipitated salt to be removed more reliably.

[ shape regulating treatment ]

The shape adjustment treatment is a treatment for adjusting the uneven shape of the surface of the glass substrate by bringing the glass substrate subjected to the frosting treatment into contact with a shape adjusting liquid. The shape-regulating liquid preferably contains at least hydrogen fluoride.

The concentration of the hydrogen fluoride in the shape-regulating liquid is preferably 3.0% by mass or more and 6.0% by mass or less, more preferably 3.5% by mass or more and 5.5% by mass or less, and still more preferably 4.0% by mass or more and 5.0% by mass or less. Thereby, the process control becomes simple.

The contact time of the shape-regulating liquid with the glass substrate is 1 minute or more, preferably 2 minutes or more, and more preferably 3 minutes or more. By setting the contact time within this range, the effect of reducing the unevenness of treatment on the surface of the glass substrate can be obtained. The upper limit of the contact time is not particularly limited, but is preferably 15 minutes or less, and more preferably 10 minutes or less.

The treatment temperature of the shape-adjusting treatment is not particularly limited, and is, for example, 15 ℃ to 30 ℃, preferably 17.5 ℃ to 27.5 ℃, and more preferably 20 ℃ to 25 ℃.

As described above, the shape-regulating liquid preferably contains hydrogen chloride.

The concentration of hydrogen chloride (HCl) in the shape-regulating liquid is preferably 5.0 mass% or more and 15.0 mass% or less, and more preferably 7.0 mass% or more and 12.0 mass% or less.

The shape-regulating liquid may contain sulfuric acid, nitric acid, phosphoric acid, and the like in addition to the above components.

The haze of the glass substrate is preferably adjusted to 45% or more and the gloss is preferably adjusted to 25% or less by the shape adjustment treatment. The glossiness is more preferably 20 or less. By adjusting the haze and the glossiness within the above ranges, a rear cover glass having a mat feel and excellent appearance can be obtained.

That is, excellent aesthetics means high haze (reliably glossing transmitted light from the back surface) and low gloss (scattering reflected light as well).

Specifically, for example, in order to increase the haze or decrease the gloss, the degree of surface unevenness may be increased.

The upper limit of the haze is not particularly limited, and is preferably 90% or less, for example.

The lower limit of the glossiness is not particularly limited, but is preferably 5 or more, and more preferably 10 or more.

The haze was the transmission haze specified in JIS K7136: 2000. The gloss was a reflected gloss (gloss 60) at 60 ℃ incidence as specified in JIS Z8741: 1997.

The surface roughness Ra of the surface of the glass substrate obtained by the shape adjustment treatment is preferably 0.1 to 4.0. mu.m, and more preferably 0.15 to 3.0. mu.m. The pitch RSm of the surface irregularities (average length of roughness curve elements) is preferably 5.0 to 50 μm, and more preferably 10 to 40 μm. When the surface roughness and the pitch of the surface irregularities are within this range, an effect of increasing light scattering can be obtained as a region where the irregularities are appropriately inclined.

The surface roughness Ra (μm) and the average length RSm of the roughness curve element can be measured by the methods specified in JIS B0601 (2001).

[ chemical strengthening treatment ]

In the present embodiment, it is preferable to perform chemical strengthening treatment after the shape adjustment treatment.

The chemical strengthening treatment is a treatment of forming a compressive stress layer formed by ion exchange on the surface of glass by bringing the glass into contact with a solution (molten salt) of an inorganic salt composition (for example, potassium nitrate) containing metal ions (for example, K ions) having a large ionic radius at a temperature not higher than the glass transition temperature. For example, an alkali metal ion (for example, Li ion and/or Na ion) having a small ionic radius in the glass is replaced with another alkali metal ion (for example, Na ion and/or K ion) having a large ionic radius. Thereby, a compressive stress layer is formed on the surface of the glass.

The inorganic salt composition preferably contains at least one of a nitrate and a sulfate. Examples of the nitrate include: sodium nitrate and potassium nitrate. Examples of the sulfate include: sodium sulfate, potassium sulfate, sodium sulfate, preferably nitrate.

As a method of bringing the glass into contact with the inorganic salt composition, there can be mentioned: a method of applying the inorganic salt composition in a paste form to glass; a method of spraying an aqueous solution of an inorganic salt composition onto glass; and a method of immersing glass in a salt bath of a molten salt of an inorganic salt composition heated to a melting point or higher. Among these, a method of immersing glass in a molten salt of an inorganic salt composition is preferable.

The chemical strengthening treatment of immersing the glass in the molten salt of the inorganic salt composition is performed, for example, by the following procedure. First, the glass is preheated, and the temperature of the molten salt is adjusted to a temperature at which the chemical strengthening treatment is performed. Next, the preheated glass is immersed in the molten salt for a predetermined time, and then the glass is pulled up from the molten salt and naturally cooled. The preheating temperature of the glass depends on the chemical strengthening treatment temperature, and is preferably 100 ℃ or higher. The chemical strengthening treatment may be performed 1 or more times, or may be performed 2 or more times under the same conditions or different conditions.

The temperature at which the chemical strengthening treatment is performed is preferably not higher than the strain point (usually 500 to 600 ℃) of the glass to be strengthened, and in order to obtain a larger Depth of compressive stress Layer (DOL), it is particularly preferably not lower than 350 ℃, more preferably not lower than 380 ℃, and still more preferably not lower than 400 ℃. From the viewpoint of suppressing deterioration and decomposition of the molten salt, the temperature at which the chemical strengthening treatment is performed is preferably 500 ℃ or lower, more preferably 480 ℃ or lower, and still more preferably 450 ℃ or lower. The time for performing the chemical strengthening treatment is preferably 1 hour to 24 hours, and more preferably 2 hours to 20 hours, in contact with the inorganic salt composition.

The glass base of the present embodimentThe body contains Li₂Therefore, the strength can be further improved by performing the chemical strengthening treatment 2 or more times.

Specifically, for example, in the first treatment, the glass substrate is brought into contact with an inorganic salt composition mainly containing sodium nitrate to perform ion exchange between Na and Li. Next, in the second treatment, for example, the glass substrate is brought into contact with an inorganic salt composition mainly containing potassium nitrate to perform ion exchange between K and Na. This is preferable because a compressive stress layer having a high DOL and a high surface stress can be formed.

The surface compressive stress of the surface preferably has a surface compressive stress value of 300MPa or more and a depth of layer (DOL) of compressive stress of 10 μm or more. This improves the scratch resistance of an acute-angle colliding object having a small-angle collision portion such as sand when the object is dropped carelessly.

After the first-step chemical strengthening treatment, the second-step chemical strengthening treatment may be performed under conditions different from those of the first-step chemical strengthening treatment (kind of salt, time, etc.). The chemically strengthened glass obtained by the two-step chemical strengthening treatment (hereinafter also referred to as two-step strengthening) has a two-stage stress distribution map of a stress distribution map (force distribution パターン) a on the surface side of the glass and a stress distribution map b on the inner side of the glass.

In the distribution of the stress value [ MPa ] at the depth x [ mu ] m from the glass surface, the stress profile a on the glass surface side can be approximated by the following function (a). The stress profile b on the glass interior side can be approximated by the following function (b). At this time, the compressive stress is defined as positive, and the tensile stress is defined as negative.

A1erfc(x/B1)+C1……(a)

A2erfc(x/B2)+C2……(b)

[ in function (a) and function (B), erfc is a complementary error function, A1 > A2 and B1 < B2. ]

The sum of C1 and C2 corresponds to the magnitude of the internal tensile stress, and the sum of a1, a2, C1, C2 corresponds to the Compressive Stress (CS) of the outermost surface.

The sum of the above functions (a) and (B) is used to determine the values of a1, a2, B1, B2, C1, and C2. At this time, in a region having a thickness t [ mu ] m and a stress value [ MPa ] at a depth x [ mu ] m from the glass surface, 0 < x < 3t/8 in the distribution, approximation is performed by the error least square method. The compressive stress is defined as positive and the tensile stress as negative. When all of the following conditions (1) to (6) are satisfied, it is particularly preferable that the compressive stress layer has both a high surface compressive stress and a deep compressive stress depth.

(1) A1[ MPa ] is more than 600

(2) A2[ MPa ] is 50 or more

(3) B1[ mu m ] is 6 or less

(4) B2[ mu ] m is more than 10% of t [ mu ] m

(5) C1+ C2[ MPa ] is-30 or less

(6) A1/B1[ MPa/mum ] is more than 100

[ other treatments ]

(protection treatment)

In the manufacturing method of the present embodiment, a protective treatment may be further performed before the sanding treatment.

The protective treatment is a treatment in which a protective layer is disposed on a region of the surface of the glass substrate where the glass gloss is left without being subjected to the antiglare treatment. For example, when the etching AG treatment is performed on one main surface of the glass substrate and the etching AG treatment is not desired to be performed on the other main surface, the protective layer is disposed on the other main surface. Then, the matte treatment and the shape adjustment treatment are performed, and the protective layer is peeled off. This makes it possible to obtain a glass substrate with an uneven shape without subjecting the other main surface on which the protective layer is disposed to an AG etching treatment.

The protective layer is not particularly limited as long as it can protect the disposed region during the sanding treatment or the shape adjustment treatment, and examples thereof include a curable resin, a resin film, and the like. The method of disposing the protective layer is also not particularly limited, and a method of applying a curable resin by a bar coater or the like and curing the resin, a method of laminating a resin film, or the like can be used. Among these, a method of forming a protective layer by applying a curable resin is preferable from the viewpoint of resistance to the scrub treatment liquid and the shape adjustment treatment liquid or easy peelability.

Examples of the curable resin include: UV curable resin, thermal curable resin. Examples of the UV curable resin include: acrylate radical polymerization resin and epoxy cationic polymerization resin. As the thermosetting resin, there can be mentioned: epoxy resin, phenolic resin, urea resin, melamine resin, unsaturated polyester resin, polyurethane resin, diallyl phthalate resin, polysiloxane resin and alkyd resin. From the viewpoint of high curing speed and reduction in the number of individual steps, a UV curable resin is preferable.

(pretreatment)

In the present embodiment, a pretreatment may be further performed before the above-described sanding treatment. In the case where the protection treatment is performed, the pretreatment is preferably performed between the protection treatment and the sanding treatment.

In the pretreatment, the surface of the glass substrate is cleaned by bringing the glass substrate before the frosting treatment into contact with a pretreatment liquid. This makes it easy to uniformly perform the subsequent frosting process and the shape adjustment process on the entire surface of the glass substrate.

The pretreatment liquid preferably contains hydrogen fluoride.

The contact time between the pretreatment liquid and the glass substrate is preferably 1 minute to 5 minutes. By adjusting the contact time within this range, the process control becomes simple.

(antifouling treatment)

In the present embodiment, after the shape adjustment treatment, an antifouling treatment may be performed. In the case of performing the chemical strengthening treatment, the stain-proofing treatment is preferably performed after the chemical strengthening treatment.

By performing the stain-proofing treatment, a stain-proofing layer is formed on the surface of the glass substrate. The antifouling layer is a layer that suppresses the adhesion of organic and inorganic substances on the surface, or a layer that has an effect of easily removing the adhered substances by cleaning such as wiping even when organic and inorganic substances are adhered to the surface. When the stain-proofing layer is formed as a stain-proofing film, it is preferably formed on the surface of the glass substrate subjected to the frosting treatment and the shape adjustment treatment.

The antifouling treatment layer is not particularly limited as long as it can impart antifouling properties. Among these, a fluorine-containing organosilicon compound coating film obtained by a hydrolysis condensation reaction of a fluorine-containing organosilicon compound is preferable. The anti-staining treatment layer may be formed on a part of the surface of the glass substrate subjected to the frosting treatment.

The method for forming the stain-proofing layer is not particularly limited. For example, a wet method such as dip coating or spray coating, or a dry method such as vapor deposition can be suitably used.

(printing treatment)

In the present embodiment, after the shape adjustment process, a printing process may be performed. The printing process is a process of disposing a printing layer on the surface of the glass substrate. This can further improve the design of the glass substrate.

The method of forming the printing layer is not particularly limited, and the printing layer can be formed by various printing methods and inks (printing materials) according to the application. Examples of the printing method include: spray printing, ink jet printing, screen printing. With these methods, even a plate-shaped glass having a large area can be printed satisfactorily. In particular, in the case of spray printing, printing is easily performed on glass having a curved portion, and the surface roughness of the printed surface is easily adjusted. On the other hand, in the screen printing, a desired print pattern is easily formed on a large plate glass so as to have a uniform average thickness. In addition, although a plurality of inks can be used, the same ink is preferable from the viewpoint of adhesiveness of the printed layer. The ink for forming the printed layer may be an inorganic ink or an organic ink. The thickness of the printing layer is preferably 5 μm or more from the viewpoint of the masking property, and the thickness of the printing layer is preferably 50 μm or less from the viewpoint of the design.