| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that it is unknown what kind of physical shape of a stamper used to manufacture an information recording medium such as an optical disk, frequently affects recording and reproduction in a disk drive, and that it is difficult to remove the stamper during back grinding, which may cause irregularities or waviness of the stamper, to measure the physical shape so that the temporal change of the irregularities or waviness of the stamper or mechanism thereof is also unknown. SOLUTION: A first displacement sensor that measures a height of a rear surface of the stamper, and a second displacement sensor that has a smaller beam diameter than the first displacement sensor and that measures a height of a surface of the stamper are arranged symmetrically with respect to the stamper in a thickness direction of the stamper. COPYRIGHT: (C)2009,JPO&INPIT
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