| 摘要 |
An objective lens actuator for an optical head includes an objective lens, an objective lens holder, a focusing coil, a pair of tracking coils, a plurality of wire springs, a magnetic circuit, and a pair of photosensors. The objective lens is constituted by an aspherical plastic lens to receive a beam reflected by an optical disk. The objective lens holder has a substantially square frame shape to hold the objective lens. The focusing coil is wound on the objective lens holder. The pair of tracking coils are arranged on parallel side surfaces of the objective lens holder, respectively. The plurality of wire springs hold the objective lens holder with a degree of freedom in focusing and tracking directions. The magnetic circuit has a substantially closed magnetic circuit arrangement to cooperate with the focusing and tracking coils to electromagnetically drive the objective lens holder. The pair of photosensors is arranged below an edge portion of the objective lens to receive, through the edge portion of the objective lens, a diffracted reflected beam which generates a tracking error signal and is obtained such that a beam emitted from a main portion of the objective lens is diffracted and reflected by a pre-groove optical disk.
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