| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical element showing little deformation after completion of film formation, and therefore, being easily handled for cutting or the like. SOLUTION: A multilayered optical thin film 4 is formed by alternately depositing SiO<SB>2</SB>thin films 2 and Nb<SB>2</SB>O<SB>5</SB>thin film 3 to about 100 layers in total on the surface of a glass substrate 1 having a negative coefficient of linear expansion. Since the substrate 1 has a negative coefficient of linear expansion and has a large difference from that of the multilayered optical thin film 4, compressive stress in the multilayered optical thin film 4 and thermal stress generating by temperature decrease compensate each other when the substrate 1 in a film formation state usually at about 200°C is transferred to a normal temperature state, and thereby, deformation (warpage) of the substrate 1 is decreased. Therefore, the substrate 1 easily processed by cutting with a dicing saw or the like and is hardly broken, and the cut-out optical element shows improved surface accuracy. COPYRIGHT: (C)2006,JPO&NCIPI
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