| 摘要 |
PURPOSE:To obtain sufficient brake force with small size and light weight, by moving the objective lens toward vertical direction to the light axis of objective lens and the information traffic via liquid damper, in the optical reader such as video disc. CONSTITUTION:The objective lens 1 is held at the holding frame 2, one end of the plate springs 3, 3' is fixed to the holding frame 2, and another end of the plate spring is fixed to the fixed members 6, 6'. The plate springs 3, 3' cause torsional deformation while more or less turning the objective lens 1 and the holding frame 2 toward the direction A vertical to the light axis. The absorbing force of the electromagnets 5, 5' displaces the objective lens 1 toward the direction A. One end of the moving rigid bodies 4, 4' is fixed to the holding frame 2, and another end is used as a part of the liquid damper. That is, the plates 6A, 6B, 6A', 6B' are provided so that another end of the moving rigid bodies 4, 4' is clipped. This is fixed to the fixing members 6, 6'. When the liquid having viscosity is filled in the gaps 7A, 7B, 7A', 7B' between the fixed member and the plate, braking force is given with the liquid with viscosity in case of movement of the lens 1. |
