| 摘要 |
PROBLEM TO BE SOLVED: To provide highly reliable optical glass which is hardly damaged even when an external force, such as impact, acts thereon.SOLUTION: Optical glass, which is bonded to a housing so as to cover an opening of the housing, includes: a glass substrate having a first principal plane on the side bonded to the housing and a second principal plane facing the first principal plane; and an optical thin film provided on at least one of the first and second principal planes. A stress acts on the optical glass in a direction expanding to the side opposite to the housing. |
