| 摘要 |
PURPOSE: To provide the optimum operation of a laser beam by providing a means for maintaining a prescribed distance which is previously decided between the center of a lens system and the center of a collision point by the beam of radiation on the face of an object. CONSTITUTION: A device for plotting a previously decided pattern on the face of the object 3 with the beam 7 of radiation is provided with the means for maintaining the prescribed distance which is previously decided between the center of the lens system 4 and the center of the collision point by the beam 7 of radiation on the face of the object. The means is constituted of a means for deciding a distance from the face of the object 3 to the lens system 4 positioned between the object 3 and a light source, a moving means moving the lens system 4 and a control means for controlling the moving means by a difference between the measured value of the distance between the lens system 4 and the face of the object 3 and a setting value. Thus, the focus of the lens 4 is maintained on the face of the object 3 and the formed pattern is made sharp. |
