| 摘要 |
PROBLEM TO BE SOLVED: To provide an ND (neutral density) filter maintaining stable spectral characteristics over a long period and to provide a structure of the ND filter with which the thin film type ND filter having an attenuation ratio varying either corresponding to a number of concentration levels or continuously is made to be easily and integrally supplied, and a method of manufacturing the same. SOLUTION: The thin film type ND filter is characterized by comprising both one or more layers of transparent dielectric films and base metal nitride films laminated and formed on a translucent substrate. Also the thin film type ND filter 61 other than the one described above is a thin film type ND filter comprising both one or more layers of transparent dielectric films 63a, 63b and 63c and light absorbing films 64a and 64b laminated and formed on a translucent substrate 62 and is characterized by having the transparent dielectric films 63a, 63b and 63c with nearly equal film thickness in an identical film and having the light absorbing films 64a and 64b with respectively different film thickness in the identical film. COPYRIGHT: (C)2004,JPO
|
