OBJECTIVE LENS DRIVING DEVICE

摘要

PROBLEM TO BE SOLVED: To reduce the weight of a movable part and to radiate the generated heat of coils by locating at least one part of a focusing coil or tracking coil or focusing coil and the tracking coil on the projection plane of an objective lens in an optical axis direction. SOLUTION: Magnets 21a and 21b magnetizing two poles so as to have opposite polarities between adjacent magnets are arranged in YZ plane symmetry with an objective lens 15 inbetween on the outside while passing the boundary surface of polarities through the center of a tracking coil 18a. The yoke of a magnetic substance is arranged so as to connect outer yokes 19a and 19b on the outside of the magnets 21a and 21b and inner yokes 20a and 20b through the air-core parts of focusing coils 18a and 17b. One part of the focusing coils 18a and 17b or tracking coil 18a is arranged on the projection plane of an objective lens 15 in the optical axis direction, a structure suitable for miniaturizing the movable part is formed and a lens holding member 16 is equipped with a hollow part facing a space surrounded with coils.