| 摘要 |
PROBLEM TO BE SOLVED: To provide a pickup device which is further light in weight and low in the cost and capable of using different types of optical disks. SOLUTION: The device is provided with a polarization rotating device capable of rotating the plane of polarization of the light outgoing from a light source 8, a driving means 20 of the polarization rotating device 16 and a polarizing plate 17 through which the light beam having passed the polarization rotating device 16 is transmitted. Thereby, it is determined whether the device 16 is to be driven or not depending on the types of optical disks, and the rotational angle of the plane of polarization of light can be varied. Furthermore since the light having transmitted the device 16 obtains an aperture limiting effect, the condensing position of the object lens is made different and light is optimally condensed on the recording layers of the optical disk different in type. |
