| 摘要 |
PURPOSE:To eliminate a necessity to wind an optical tape around a rotary drum, etc., by using a reflected laser light from a cam-shaped prism having a reflecting surface in a necessary shape. CONSTITUTION:A laser beam by a laser diode 8 and a collimate lens 9 passes a beam splitter 10, prisms 2 and 3, etc., it is reflected at an irradiating point moved in the circumferential direction of a reflecting surface 6a in a shape in which a height is gradually changed over the circumference of a cam-shaped prism 6 to be turned integrally with a rotary drum 1, and it is made into an optical tape scanning light. By such a constitution, the necessity to obliquely wind the optical tape around the rotary drum is eliminated, and the generation of the damage of the optical tape, etc., can be reduced. |
