| 摘要 |
PROBLEM TO BE SOLVED: To produce a concave lens having sufficient shape accuracy by polishing. SOLUTION: The concave lens 1 is constituted of optical glass and has a spherical concave surface 2 formed by polishing. The center thickness t of the concave lens 1 is 0.5 mm or less, and a ratio D/t of a diameter D with respect to the center thickness t is 30 or more. A Young's modulus of the optical glass that composes the concave lens 1 is 80 GPa or more. It is preferable that the degree of wear of the optical glass be 500 or less, and it is preferable that Knoop hardness of the optical glass be 600 or less. COPYRIGHT: (C)2011,JPO&INPIT
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