PROTECTING DEVICE FOR OBJECTIVE LENS

摘要

PURPOSE:To prevent effectively an objective lens from the adhesion of dust by arranging rotatable protecting plate above the objective lens. CONSTITUTION:The protecting plate 3 fitting a magnet piece 4 to its one end is rotatably fitted to a rotary shaft of a protecting case 1 so as to cover the immediately apper part of the objective lens 6. A coil 5 is arranged near the magnet piece 4 and the protecting plate 3 usually cover the objective lens 6 by a spring 2 laid between the case 1 and the plate 3. At the time of reading operation, current is supplied to the coil 5, the magnet piece 4 is adsorbed and the protecting plate 3 is rotated, so that a laser beam is radiated. Consequently, the objective lens can be effectively prevented from the adhesion of dust.