Transparent substrate and display device
A transparent substrate includes a first principal surface; a second principal surface as a principal surface on the opposite side of the first principal surface; a lateral surface extending between the first principal surface and the second principal surface; and a first boundary surface disposed between the first principal surface and the lateral surface and having a plurality of concave portions; wherein the first boundary surface is configured such that each of the concave portions has a bottom with a curvature and that the frequency of a maximum curvature is less than 3% in a frequency distribution of the curvatures of the concave portions.
1. A transparent substrate comprising:
a first principal surface;
a second principal surface as a principal surface on the opposite side of the first principal surface;
a lateral surface extending between the first principal surface and the second principal surface; and
a first boundary surface disposed between the first principal surface and the lateral surface and having a plurality of concave portions;
wherein the first boundary surface is configured such that each of the concave portions has a bottom with a curvature and that a frequency of a maximum curvature is less than 3% in a frequency distribution of the curvatures of the concave portions, and
the first boundary surface is configured such that the difference between a maximum frequency and an intermediate frequency is 1% or more in the frequency distribution of the curvatures of the concave portions.
2. A transparent substrate, comprising:
a first principal surface;
a second principal surface as a principal surface on the opposite side of the first principal surface;
a lateral surface extending between the first principal surface and the second principal surface; and
a first boundary surface disposed between the first principal surface and the lateral surface and having a plurality of concave portions,
wherein the first boundary surface is configured such that each of the concave portions has a bottom with a curvature and that a frequency of a maximum curvature is less than 3% in a frequency distribution of the curvatures of the concave portions, and
the first boundary surface is configured such that the maximum frequency has a curvature of 1×10 −5 to 9.5×10 −5 nm −1 in the frequency distribution of the curvatures of each of the concave portions.
3. The transparent substrate according to claim 1 , wherein the first boundary surface has an arithmetic average roughness Ra 1 of 3 to 10 μm.
4. The transparent substrate according to claim 2 , wherein the first boundary surface is configured such that the difference between a maximum frequency and an intermediate frequency is 1% or more in the frequency distribution of the curvatures of the concave portions.
5. The transparent substrate according to claim 1 , further comprising:
a third boundary surface disposed between the second principal surface and the lateral surface and having a plurality of concave portions;
wherein the third boundary surface is configured such that the difference between a maximum frequency and an intermediate frequency is at least 1% in the frequency distribution of the curvatures of each of the concave portions.
6. The transparent substrate according to claim 5 , wherein the third boundary surface has an arithmetic average roughness Ra 3 of 3 to 10 μm.
7. The transparent substrate according to claim 5 , wherein the third boundary surface is configured such that the maximum frequency has a curvature of 1×10 −5 to 9.5×10 −5 nm −1 in the frequency distribution of the curvatures of the concave portions.
8. A transparent substrate, comprising:
a first principal surface;
a second principal surface as a principal surface on the opposite side of the first principal surface;
a lateral surface extending between the first principal surface and the second principal surface;
a first boundary surface disposed between the first principal surface and the lateral surface and having a plurality of concave portions; and
a second boundary surface disposed between the first principal surface and the first boundary surface,
wherein the first boundary surface is configured such that each of the concave portions has a bottom with a curvature and that a frequency of a maximum curvature is less than 3% in a frequency distribution of the curvatures of the concave portions, and
an arithmetic average roughness Ra 2 of the second principal surface is smaller than an arithmetic average roughness Ra 1 of the first boundary surface.
9. The transparent substrate according to claim 8 , wherein the arithmetic average roughness Ra 2 of the second boundary surface is 0.02 to 0.15 μm.
10. The transparent substrate according to claim 8 , wherein the first principal surface is apart from a junction between the first boundary surface and the second boundary surface by a distance h 1 of longer than 0 μm and not longer than 80 μm in a thickness direction of the transparent substrate.
11. The transparent substrate according to claim 5 , further comprising a fourth boundary surface disposed between the second principal surface and the third boundary surface;
wherein an arithmetic average roughness Ra 4 of the fourth boundary surface is smaller than an arithmetic average roughness Ra 3 of the third boundary surface.
12. The transparent substrate according to claim 11 , wherein the arithmetic average roughness Ra 4 of the fourth boundary surface is 0.02 to 0.15 μm.
13. The transparent substrate according to claim 11 , wherein the second principal surface is apart from a joint between the third boundary surface and the fourth boundary surface by a distance h 2 of longer than 0 μm and not longer than 80 μm in the thickness direction of the transparent substrate.
14. A display device comprising:
the transparent substrate recited in claim 1 ;
a display panel covered by the transparent substrate; and
a case for housing the display panel;
wherein the transparent substrate is disposed in such a direction that the first principal surface confronts a display surface of the display panel.
15. The transparent substrate according to claim 2 , further comprising:
a third boundary surface disposed between the second principal surface and the lateral surface and having a plurality of concave portions;
wherein the third boundary surface is configured such that the difference between a maximum frequency and an intermediate frequency is at least 1% in the frequency distribution of the curvatures of each of the concave portions.
16. The transparent substrate according to claim 15 , wherein the third boundary surface has an arithmetic average roughness Ra 3 of 3 to 10 μm.
17. The transparent substrate according to claim 15 , wherein the third boundary surface is configured such that the maximum frequency has a curvature of 1×10 −5 to 9.5×10 −5 nm −1 in the frequency distribution of the curvatures of the concave portions.
18. The transparent substrate according to claim 8 , further comprising:
a third boundary surface disposed between the second principal surface and the lateral surface and having a plurality of concave portions;
wherein the third boundary surface is configured such that the difference between a maximum frequency and an intermediate frequency is at least 1% in the frequency distribution of the curvatures of each of the concave portions.
19. The transparent substrate according to claim 18 , wherein the third boundary surface has an arithmetic average roughness Ra 3 of 3 to 10 μm.
20. The transparent substrate according to claim 18 , wherein the third boundary surface is configured such that the maximum frequency has a curvature of 1×10 −5 to 9.5×10 −5 nm −1 in the frequency distribution of the curvatures of the concave portions.