| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a compatible optical pickup including an optical unit that emits 1st to 3rd lights of wavelengths λ1, λ2 and λ3 suitable to 1st to 3rd optical disks having mutually different formats and can receive and detect lights reflected by the 1st to 3rd optical disks, an objective which converts the 1st to 3rd lights made incident from the optical unit side to form light spots on the optical disks; and 1st and 2nd phase compensators which are arranged on the entrance pupil side of the objective to cause the 2nd and 3rd lights to vary in phase difference. <P>SOLUTION: The 1st phase compensator compensates the phase of only the 2nd light and causes the other 1st and 3rd lights to travel as they are; and the 2nd phase compensator compensates the phase of only the 3rd light and causes the other 1st and 2nd light to travel as they are. Since, the couple of phase compensators which each compensate the phases of lights each having one wavelength different from each other are provided so as to compensate a spherical aberration due to the thickness differences among the disks and an aberration such as a chromatic aberration due to the wavelength differences of lights in use, even when the single objective lens is used, the three kinds of optical disks which are different in thickness can be compatible for recording and/or reproduction. <P>COPYRIGHT: (C)2003,JPO |
