| 摘要 |
PURPOSE:To facilitate easy control of the distance between an image forming optical system and a writing surface by securing a free movement of a frame stored in another frame toward an optical axis while a holding means holds an optical system and an optical switching member and displacing said holding means by a displacement means. CONSTITUTION:The light of a light source lamp 11 is condensed by a condenser lens and illuminates the element array part of an optical switching element array 13 in a slit form in the lengthwise direction of said element array part. Under such conditions, the light is transmitted. Thus the writing position on the wiring surface is illuminated by the function of an image forming optical system 2 in the direction vertical to a drawing with a straight line form of small width. A cam driving shaft 55 is shifted in the lengthwise direction by a knob 58, and a holding means 3 is displaced toward the optical axis via a roll 52 and a sloping surface of a cam 51 displacing incorporatedly with the shaft 55. Then the control is carried out to minimize the width of the linear illuminating part to realize the correct positional relation between the system 2 and the writing surface. The displacement means contains the cam 51, the roll 52, a shaft 53, an elastic member 54, a cam driving shaft 55, a stopper 57'', a spring 57', bearings 56 and 59, a control screw 57, a knob 58 and a guide (not shown in the diagram) respectively. |
