| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical device capable of miniaturizing not only an optical pickup but also an information recording device or the like itself including the optical pickup by reducing the number of components as the optical pickup. <P>SOLUTION: In the optical pickup P1, the light axis of red light beam RL for a DVD and the light axis of blue light beam BL for a high recording density optical disk are made identical and the respective optical disks are irradiated with the light beams. The optical pickup is provided with an expander first lens 4 and an expander second lens 6 compensating aberration produced at the blue light beam ML and the red light beam RL and a dichroic prism 5 disposed on the optical paths of the blue light beam BL and the reflection beam thereof between the expander first lens 4 and the expander second lens 6. The expander second lens 6 cooperates with the expander first lens so that spherical aberration produced in the blue color beam BL is compensated and the red light beam RL is converted into parallel light. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
