| 摘要 |
PROBLEM TO BE SOLVED: To provide a deformable mirror with which a mirror surface can be accurately deformed into required form and held while being hardly affected by the fluctuation of environment or electric circuit and further the number of apertures on an objective lens can be changed together with aberration compensation corresponding to the thickness of the substrate of an optical disk. SOLUTION: This mirror is provided with a flexible member 2 which can be elastically deformed with its surface as a reflecting plane, and a columnar substrate 7 which is arranged on the rear surface side of this flexible member 2 and has an inside rugged part 4 and an outside rugged part 5 formed at sections facing the rear surface of the flexible member. Then, the flexible member 2 is attracted to the rugged parts 4 and 5, the form of its rear surface is changed, the spherical aberration is changed based on the surface form of the inside rugged part 4 and the numerical apertures is changed based on the surface form of the outside rugged part 5. |
