| 摘要 |
PROBLEM TO BE SOLVED: To compensate the chromatic aberration of an objective lens. SOLUTION: This optical device for compensating the chromatic aberration where the wavelength region of a laser beam is set to <=500 nm is combined and used with the objective lens 7 whose NA(numerical aperture) is >=0.6. Then, an optical system is constituted by using the 1st optical device for compensating the chromatic aberration 3 obtained by sticking a piano-convex lens 1 and a plano-concave lens 2 and the 2nd optical device for compensating the chromatic aberration 6 obtained by sticking a piano-concave lens 4 and a plano-convex lens 5. |
