| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical element of which change in optical property is small even when it is kept under severe (bad) circumstances. <P>SOLUTION: In an optical element, a low refractive index layer consisting of a material of the low refractive index of 1.5 or lower, an intermediate refractive index layer consisting of a material of the intermediate refractive index of higher than 1.5 and lower than 1.6, and a high refractive index layer consisting of a material of the high refractive index of 1.6 or higher, are laminated on a substrate against the light in the wavelength range of 150 nm or longer and 500 nm or shorter in the design central wavelength. The intermediate refractive index layer has a film stress different from that of the low refractive index layer or the high refractive index layer, and its optical film thickness is an integral multiple of half the design central wavelength. <P>COPYRIGHT: (C)2007,JPO&INPIT |
