| 摘要 |
PURPOSE:To reduce the weight of a mobile part to improve the following-up capacity and the frequency characteristic and simplify and miniaturize the structure by fixing a light emitting element to a supporting means which freely rotatably supports an objective lens and fixing a light receiving element to an immobile member. CONSTITUTION:A holding member 22 which holds an objective lens 20 is supported on a supporting member 30, which is pivotally supported by an immobile member 34, which flat spring 24, 26, and 28 between them, and a light emitting element 40 is fixed to the supporting member 30 and a light receiving element 42 is fixed to a supporting base 44. The lens 20 is driven around a revolving shaft 36 in the tracking direction by coils 46 and 48 and in the focusing direction by a coil 54. Since the weight of each of a focusing system consisting of the lens 20, the member 22, coils, etc., and a tracking system consisting of the member 30 and the element 40 is light and the latter is near the revolving shaft, the influence of the weight is small. The following-up capacity and the frequency characteristic are improved because the weight of the mobile part is light, and the structure is miniaturized because complicated weight balance is unnecessary.
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