| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical filter which has a reflection band showing a relatively high reflectivity and has a high flexibility of design with respect to the width and center wavelength of the reflection band. SOLUTION: The optical filter is a multilayer film comprising j layers in total on a surface 100S of an optical substrate 100 and has odd layers (a first layer T1, a third layer T3, a fifth layer T5,...) and even layers (a second layer T2, a fourth layer T4, and a sixth layer T6,...) having mutually different refractive indexes alternately laminated on the optical substrate 100. The optical film thickness of each layer periodically changes in a lamination direction as a whole and, for example, satisfies prescribed conditional expressions (1) and (2). COPYRIGHT: (C)2009,JPO&INPIT
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