| 摘要 |
PROBLEM TO BE SOLVED: To reproduce plural optical disks with one condensing optical system with a low cost without complication and to cope with even an optical disk of high NA. SOLUTION: A refracting face S1 on the light source side of an objective lens 16 of an optical pickup device 10 is provided with three split faces Sd1 to Sd3, and the second split face Sd2 is made into a diffracting face. In the case of reproducing of a first optical disk whose transparent substrate has a thickness t1, the luminous flux passing first and third split faces Sd2 and Sd3 and 0th-order light through the second split face Sd2 are used; and in the case of reproducing of a second optical disk whose transparent substrate has a thickness t2 (t2≠t1), the luminous flux passing the first split face Sd1 and first-order light through the second split face are used. |
