| 摘要 |
PURPOSE:To obtain an optical disk of high quality by using a fluid containing ammonium ion suppressed to <=10ppm as a coolant. CONSTITUTION:A fluid containing ammonium ion suppressed to <=10ppm is used as a coolant for a temp. controlling means, and the production device is equipped with a detecting means for ammonium ion in this fluid. When the concn. of ammonium ion is estimated to exceed 10ppm from the result of measurement by the detecting means, a new coolant containing <=10ppm ammonium ion is added. By this method, a substrate is produced by using the fluid in which ammonium ion is suppressed to <=10ppm as a coolant for the temp. controlling means. An optical disk using this substrate has no defect, and thereby, high-quality optical disks can be produced at high yield. |
