Window and method of manufacturing the same
A window includes a base region and a compressive stress region disposed on the base region. The compressive stress region includes Li + , Na + , and K + ions. The compressive stress region includes a first compressive stress portion in which a concentration of the K + ions decreases, a concentration of Na + ions increases, and a concentration of the Li + ions increases, from a surface of the window toward the base region. A second compressive stress portion is adjacent to the first compressive stress portion. In the second compressive stress portion, the concentration of the Na + ion decreases and the concentration of the Li + ion increases, from the first compressive stress portion toward the base region. The window thereby has a high surface compressive stress value and impact resistance.
1. A window comprising:
a base region; and
a compressive stress region disposed on the base region and including Li + , Na + , and K + ions,
wherein the compressive stress region comprises:
a first compressive stress portion in which a concentration of the K + ions decreases, a concentration of the Na + ions increases, and a concentration of the Li + ions increases, from a surface of the window toward the base region; and
a second compressive stress portion adjacent the first compressive stress portion, wherein, in the second compressive stress portion, the concentration of the Na + ions decreases and the concentration of the Li + ions increases from the first compressive stress portion toward the base region.
2. The window of claim 1 , wherein:
the first compressive stress portion has a first compressive stress pattern in which a compressive stress value decreases with a first slope from the surface toward the base region,
the second compressive stress portion has a second compressive stress pattern in which the compressive stress value decreases with a second slope different from the first slope, from the first compressive stress portion toward the base region, and
each of the first slope and the second slope is defined as an amount of decrease in the compressive stress value as a depth inside the window increases in a direction from the surface toward the base region.
3. The window of claim 2 , wherein the first slope is greater than the second slope.
4. The window of claim 1 , wherein a density of the first compressive stress portion is greater than a density of the second compressive stress portion.
5. The window of claim 1 , wherein the second compressive stress portion does not comprise K + ions.
6. The window of claim 1 , wherein the thickness of the compressive stress region is within a range from about 130 μm to about 150 μm.
7. The window of claim 1 , wherein the thickness of the first compressive stress portion is within a range from about 5 μm to about 15 μm.
8. The window of claim 1 , wherein a compressive stress value at the surface is about 650 MPa or larger.
9. The window of claim 1 , wherein the base region comprises SiO 2 of from about 50 wt % to about 80 wt %, Al 2 O 3 of from about 10 wt % to about 30 wt %, and Li 2 O 3 of from about 3 wt % to about 20 wt %.
10. The window of claim 1 , wherein the window comprises a flat portion and at least one bent portion adjacent to the flat portion.
11. A window comprising a compressive stress region at a surface thereof,
wherein the compressive stress region comprises;
a first compressive stress portion in which a concentration of the K + ions decreases, a concentration of the Na + ions increases, and a concentration of the Li + ions increases, from the surface toward a center of the window; and
a second compressive stress portion adjacent to the first compressive stress portion, wherein, in the second compressive stress portion, the concentration of the Na + ions decreases and the concentration of the Li + ions increases from the first compressive stress portion toward the center.
12. The window of claim 11 , wherein:
the first compressive stress portion has a first compressive stress pattern in which a compressive stress value decreases with a first slope from the surface toward the center,
the second compressive stress portion has a second compressive stress pattern in which the compressive stress value decreases with a second slope greater than the first slope, from the first compressive stress portion toward the center, and
each of the first slope and the second slope is an amount of decrease in the compressive stress value as a depth inside the window increases from the surface toward the center.
13. The window of claim 1 , wherein the second compressive stress portion is adjacent to the first compressive stress portion and wherein the second compressive stress portion is disposed between the first compressive stress portion and the base region.
14. The window of claim 11 , wherein the second compressive stress portion is adjacent to the first compressive stress portion and wherein the second compressive stress portion is disposed between the first compressive stress portion and the center of the window.