| 主权项 |
1. An optical module comprising:
an interference filter including a first substrate having a first thermal expansion coefficient, a second substrate which faces the first substrate, a first reflection film which is formed on the first substrate, and a second reflection film which is formed on the second substrate and faces the first reflection film through a gap; and a fixing portion to which the first substrate of the interference filter is fixed, having a second thermal expansion coefficient which has a value different from the first thermal expansion coefficient, wherein the interference filter is fixed to the fixing portion through an adhesive layer of gel-like resin; and wherein when the thickness of the adhesive layer is Ta (mm), the linear expansion coefficient of the first substrate is α1 (K−1), the Young's modulus of the first substrate is E1 (GPa), the thickness of the first substrate is T1 (mm), the linear expansion coefficient of the fixing portion is α2 (K−1), the Young's modulus of the fixing portion is E2 (GPa), the thickness of the fixing portion is T2 (mm), and a coefficient based on the gel-like resin is A, the thickness of the adhesive layer satisfies the following formula (1) in a case where (α1·E1·T12)≦(α2·E2·T22), and satisfies the following formula (2) in a case where (α1·E1·T12)>(a2·E2·T22):
Ta≧A·(α2·E2·T22)/(α1·E1·T12) (1)Ta≧A·(α1·E1·T12)/(α2·E2·T22) (2).
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