Glass substrate
A glass substrate comprising a rectangular glass sheet having a first main surface and a second main surface opposite the first main surface, the glass substrate having a first side and a second side which are adjacent to each other in a view along a thickness direction of the glass sheet, in which a thickness tolerance is less than 6.26 μm in a first cross section which is a cross section in the thickness direction of the glass sheet along a straight line parallel to the first side, the thickness tolerance being a difference between the maximum value and the minimum value of the thickness of the glass sheet.
1. A glass substrate comprising a rectangular glass sheet comprising a first main surface and a second main surface opposite the first main surface,
wherein the glass substrate comprises a first side and a second side which are adjacent to each other in a view along a thickness direction of the glass sheet,
wherein a thickness tolerance is less than 6.26 μm in a first cross section which is a cross section in the thickness direction of the glass sheet along a straight line parallel to the first side, wherein the thickness tolerance is a difference between the maximum value and the minimum value of the thickness of the glass sheet, and
wherein the first main surface comprises a roughened region and an unroughened region, and a ratio of a roughness of the roughened region to the unroughened region is greater than 1.
2. The glass substrate according to claim 1 , wherein the thickness tolerance is less than 7.12 μm in every cross section in the thickness direction of the glass sheet.
3. The glass substrate according to claim 1 , wherein a mean value of absolute values of first differential values of the thickness in the first cross section is less than 1.72E-02.
4. The glass substrate according to claim 1 , wherein a standard deviation of absolute values of first differential values of the thickness in the first cross section is 1.5E-03 or less.
5. The glass substrate according to claim 1 , wherein the maximum value of absolute values of second differential values of the thickness in the first cross section is 6.0E-03 or less.
6. The glass substrate according to claim 1 , wherein a standard deviation of absolute values of second differential values of the thickness in the first cross section is 1.5E-04 or less.
7. The glass substrate according to claim 1 , satisfying the following relationships:
Ra 1 >0.5 nm; and
Ra 2 ≤0.5 nm,
wherein Ra 1 is the arithmetic mean roughness of the roughened region, and Ra 2 is the arithmetic mean roughness of the unroughened region.
8. The glass substrate according to claim 1 , wherein the roughened region has a smaller area than the unroughened region, and
an area ratio of the unroughened region to the roughened region is from 3 to 300.
9. The glass substrate according to claim 1 , wherein the first main surface comprises a linear form roughened region in a direction parallel to the first side.
10. The glass substrate according to claim 1 , wherein the first main surface comprises a plurality of linear form roughened regions in a direction parallel to the first side.
11. The glass substrate according to claim 9 , wherein the roughened region has a width of from 10 mm to 1,000 mm in a direction parallel to the second side.
12. The glass substrate according to claim 1 , wherein the glass sheet is an alkali-free glass.
13. The glass substrate according to claim 1 , wherein the glass sheet does not have a polishing flaw in at least one of the first main surface and the second main surface.
14. The glass substrate according to claim 1 , wherein the glass sheet has a thickness of 1.0 mm or less.
15. The glass substrate according to claim 1 , wherein the glass sheet comprises a layer having a thickness of 10 μm or more and comprising moisture in an amount of 80% or less of a moisture content of a bulk, in at least one of the first main surface and the second main surface.
16. The glass substrate according to claim 1 , wherein the first main surface comprises a first region and a second region, and a ratio of a fluorine content in the first region to a fluorine content in the second region is greater than 1.
17. A glass substrate comprising a rectangular glass sheet comprising a first main surface and a second main surface opposite the first main surface,
wherein the glass substrate comprises a first side and a second side which are adjacent to each other in a view along a thickness direction of the glass sheet,
wherein a thickness tolerance is less than 6.26 μm in a first cross section which is a cross section in the thickness direction of the glass sheet along a straight line parallel to the first side, wherein the thickness tolerance is a difference between the maximum value and the minimum value of the thickness of the glass sheet,
wherein the first main surface comprises a first region and a second region, and
a ratio of a fluorine content in the first region to a fluorine content in the second region is greater than 1.
18. The glass substrate according to claim 17 , satisfying the following relationships:
0.5 wt %≤F 1 ≤5 wt %; and
0≤F 2 ≤0.15 wt %,
wherein F 1 is the fluorine content of the first region, and F 2 is the fluorine content of the second region.
19. The glass substrate according to claim 17 , wherein the first region has a smaller area than the second region, and an area ratio of the second region to the first region is from 3 to 300.
20. The glass substrate according to claim 17 , wherein the first main surface comprises a linear form first region in a direction parallel to the first side.
21. The glass substrate according to claim 17 , wherein the first main surface comprises a plurality of linear form first regions in a direction parallel to the first side.
22. The glass substrate according to claim 20 , wherein the first region has a fluorine content having a slope along a direction parallel to the second side of from 0.001 wt %/mm to 0.15 wt %/mm.