| 摘要 |
PURPOSE:To perform drawing with high accuracy, by correcting the position of a laser beam spot with respect to the shift of the drawing point in a mechanical scanning direction and in a beam scanning direction generated by the yawing motion error of a unidirectional moving table. CONSTITUTION:The photoplotter is constituted by containing two photoelectric type linear encoders arranged on both sides of a uniaxial moving table 7, a rotary polyhedral mirror 4 in a beam path, a drawing signal generating part 10, the acousto-optical deflector 3 arranged between said mirror and an electro- optical modulator 2 to deflect laser beam in the moving direction of the uniaxial moving table, a drawing time control part 12 for adjusting drawing timing and an operational processing part 11 connected to the aforementioned to photoelectric type linear encoders 8 to operate a laser deflecting angle, which moves a laser beam spot 6 in quantity equal to the moving quantity of a drawing point caused by the yawing motion error of the aforementioned uniaxial moving table, and a drawing time adjusting time to control the aforementioned acousto- optical deflector 3 and drawing time control part 12. |
