| 摘要 |
<p>A cover glass in which an outermost surface has a compressive stress of 500 MPa or higher and which has a compressive stress layer having a depth of 15 µm or larger and has a plate thickness less than 0.8 mm. In a sandpaper falling-ball test in which the cover glass is placed on a granite table together with sandpaper P30 (JIS R6252, 2006) so that the upper surface of the cover glass is in contact with the rubbing surface of the sandpaper, and then a spherical object which is constituted of stainless steel and has a diameter of 0.75 inch and a weight of 4 g is dropped thereonto from above, the average falling-ball height at fracture is 17 cm or higher.</p> |
