| 摘要 |
PURPOSE:To suppress the distortion due to hysteresis within a permissible range by overlapping an opto-base main body made of a plastic member on a metallic plate with a small hysteresis and combining the base main body based on the metallic plate. CONSTITUTION:The opto-base 11 is constituted by overlapping the metallic plate 13 on the base main body 12 made of a plastic member so as to combine them incorporatedly and the opto-base 11 is formed based on the metallic plate 13 having a small temperature hysteresis. Moreover, an objective lens actuator 17 is supported to the base main body 12 via the metallic plate 13. Then an optical sensor 16 is arranged on the face of a prolonged part 132 of the metallic plate 13 used as the reference so that the center is aligned on the prolonged line of the return optical axis. Thus, the temperature hysteresis of the base main body 12 is compensated by the metallic plate 13 and the distortion of the plastic member, when it is within a range of a storage temperature cycle, is suppressed within a permissible limit. |
