| 摘要 |
<p>A chamfer angle discrimination method for discriminating whether a chamfer portion of a memory disc substrate has a predetermined chamfer angle, includes the steps of taking an image of a peripheral end surface (Ma) of the memory disc substrate (M) while irradiating the peripheral end surface (Ma) with light, calculating a width (tO) of a flat portion (Mc) of the peripheral end surface (Ma) excluding the chamfer portion based on the image, and discriminating whether the chamfer portion has a predetermined chamfer angle υ based on the width (tO). This method enables an automatic detection of the existence of a memory disc substrate (M) having a chamfer angle different from those of the other memory disc substrates (M) with high accuracy.</p> |
