| 摘要 |
PURPOSE:To lead a linear tracking arm with high precision by arranging a mirror which is bent sectionally, and a light emitting element and a couple of photodetecting elements opposite to the mirror. CONSTITUTION:Light from a light emitting element 14 is nearly collimated through a convex lens 15 and reflected by a bend-sectioned mirror 16 to reach photodetecting elements 17a and 17b. The reflected light reaching the photodetecting elements 17a and 17b varies with the inclination of a cantilever 11, and consequently the output voltages of the photodetecting elements 17a and 17b vary. Those output voltages are compared mutually by a comparator 18, and a DC output which corresponds to the difference voltage of the comparator 18 is applied to a motor driving circuit 21 through a low-pass filter 19 and a hysteresis comparator 20 to control the turning speed and direction of an arm leading motor 22. In addition, the outside surface of the mirror 16 may be made into a reflecting surface and a mirror in a different shape may be used. |
