| 摘要 |
PURPOSE:To execute a random access to an information track by connecting a pair of moving pieces which can move independently and are provided with a reflecting mirror, and an optical system supporting member by diagonal connecting members, respectively, and moving an objective lens extending over a considerable distance. CONSTITUTION:Two parallelogram links are formed by connecting one end of diagonal connecting members 12-15 to moving pieces 2, 4 which can move independently in the directions X1, X2 on a rail 10, and connecting an optical system supporting member 16 to the other end. Parallel rays from a light source 24 are reflected by reflecting mirrors 30, 32, pass through an objective lens 18 and form a minute spot at a point P of a disk 20, and its reflected light is led to a detector 36 through its reverse path. A tracking control and a focus control are executed by moving the moving pieces 2, 4 in the same direction, and moving them in the opposite direction, respectively. Accordingly, a random access to an information track can be executed by reducing a movable part and moving the objective lens 18 in the right and left directions and the Y direction extending over a considerable distance.
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