Method for producing glass article, and glass article
A method for producing a glass article from a glass member including a glass substrate including a first main surface, a second main surface and an end face, and an irregular layer formed in at least one of main surfaces, includes forming an irregular layer having a glass transition point Tg which is equal to or lower than a glass transition point in a central part of the glass member in a thickness-direction sectional view and performing a heat treatment on the glass member so as to have an equilibrium viscosity in the central part of the glass member in thickness-direction sectional view of 10 17 Pa·s or lower.
1. A glass article comprising:
a first main surface;
a second main surface;
an end face; and
an antiglare layer provided on at least one surface selected from the group consisting of the first main surface and the second main surface, wherein the antiglare layer is formed by a process of forming surface irregularities on the at least one surface of the glass article, the process comprising heating the glass article to a temperature equal to or higher than a softening point thereof to deform the glass article;
wherein
a difference between a glass transition point Tg of the antiglare layer and a glass transition point Tg 0 in a central part of the glass article in a thickness-direction sectional view, (Tg 0 −Tg), is from 3° C. to 20° C.; and
the at least one surface comprises a curvature part.
2. The glass article according to claim 1 ,
wherein
a glass transition point Tg of the antiglare layer is equal to or lower than a glass transition point Tg 0 in a central part of the glass article in a thickness-direction sectional view;
the antiglare layer has arithmetic mean roughness Sa within a surface of 0.06 μm or less and surface skewness Ssk of less than 0 in a surface shape obtained by measuring a region of (101 μm×135 μm) to (111 μm×148 μm) in the antiglare layer with a laser microscope; and
the glass article comprises a convex part having an average diameter, in terms of a true circle, at a height of +0.01 μm from a bearing height in an image processed surface of from 0.4 μm to 1.1 μm with reference to the bearing height when an image obtained from XYZ data of the surface shape measured with the laser microscope is filtered by image processing software to obtain a smoothed image, and XYZ data of the smoothed image are subtracted from XYZ data of the surface shape to obtain the image processed surface.
3. The glass article according to claim 2 , wherein the at least one surface comprises a curvature part.
4. The glass article according to claim 1 , wherein
a ratio Z 1 /Z 0 of an atomic composition ratio Z 1 in the antiglare layer to an atomic composition ratio Z 0 in the central part of the glass article in the thickness-direction sectional view is from 0.9 to 1.1 when an atomic composition ratio Z between Si and an element X selected from the group consisting of Al, B, Zr and Ti is defined as X/Si.
5. The glass article according to claim 1 , wherein
an alkali metal composition ratio expressed by {K/(Li+Na+K)} is larger in the antiglare layer than in the central part of the glass article in the thickness-direction sectional view.
6. The glass article according to claim 1 , wherein the antiglare layer comprises a fluorine atom (F) or a chlorine atom (Cl).
7. The glass article of claim 2 , wherein the convex part has the average diameter of from 0.79 μm to 1.06 μm.
8. A method for producing the glass article of claim 1 from a glass member comprising a glass substrate comprising a first main surface, a second main surface, an end face, and an irregular layer formed on at least one of the first and second main surfaces, the method comprising:
forming the irregular layer having a glass transition point Tg which is equal to or lower than a glass transition point in a central part of the glass member in a thickness-direction sectional view; and
performing a heat treatment on the glass member so as to have an equilibrium viscosity in the central part of the glass member in the thickness-direction sectional view of 10 17 Pa·s or lower.
9. The method for producing a glass article according to claim 8 , wherein the irregular layer is formed by etching treatment.
10. The method for producing a glass article according to claim 8 , wherein the irregular layer is formed by blasting treatment.
11. The method for producing a glass article according to claim 8 , wherein the heat treatment is performed during molding.
12. The method for producing a glass article according to claim 11 , wherein in the molding, the glass member is mounted on a mold so that one of the main surfaces or the end surface of the glass member is in contact with the mold, and then the glass member is deformed.
13. The method for producing a glass article according to claim 12 , wherein in the molding, temperature control is performed on a surface of the glass member that is not in contact with the mold.
14. The method for producing a glass article according to claim 13 , wherein the surface of the glass member that is not in contact with the mold comprises the irregular layer.
15. The method for producing a glass article according to claim 8 , wherein the heat treatment is performed during annealing.
16. The method for producing a glass article according to claim 8 , wherein the heat treatment is performed by radiation heating.
17. The method for producing a glass article according to claim 8 , wherein the heat treatment is performed by convection heating.