| 摘要 |
PURPOSE: An actuator for a light pickup is provided to make magnetic forces at the upper, lower, and central portions be similar thereto by differently setting winding numbers at the upper, lower, and central portions. CONSTITUTION: A focus coil(31) is winded on the outer circumference of a bobbin corresponded to a magnet(25a) and drives an object lens toward a focus direction. The numbers of the upper and lower portions of focus coil(31) are more than that of the central portion of focus coil(31). Average magnetic flux densities of upper, central, and lower portions of focus coil(31) are 3110 gauss, 4220 gauss, and 2655 gauss, respectively. The average magnetic flux densities of the upper and lower portions are less than that of the central portion caused by an influence of a base. A tracking coil is arranged at the circumference of the focus coil(31) opposite to magnetic and drives the object lens toward a disk track direction(Y-axis direction) by a direction of the applied current and an interactive electromagnetic force between the magnetic.
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