| 摘要 |
<p>One aspect of the present invention is a method of manufacturing glass substrates for hard disk drives (HDDs) characterized in that, for a glass blank, when the amount of retardation from a cross section is measured while cutting the glass blank in a strip shape in a direction perpendicular to the main surfaces just before a chemical strengthening step, the difference between a first maximum value for the amount of retardation per unit optical path length in a range up to 10 mum from one main surface, and a second maximum value for the amount of retardation per unit optical path length in a range up to 10 mum from the other main surface is not more than 10 nm/mm.</p> |
