| 摘要 |
PURPOSE:To prevent the generation of the striped pattern in the roll circumferential direction and to improve the appearance of a steel sheet by impressing the RF signal synchronized with a laser pulse light on an acoast optical element and sliding the incident position on the roll surface of the laser light. CONSTITUTION:A pulse laser oscillator 1 oscillates a pulse laser light L of a frequency F repeatedly by synchronizing with the output signal of a RF signal generator 11. On the other hand the output signal of the RF signal generator 12 repeating turn-on, turn-off with the 1/2F frequency is impressed on the AO element 2 for scanning and the laser light passed through the element becomes the laser light L2 diffracted by an angle theta. When the RF signal is removed, the laser light L is linearly propagated in the element, becoming of a laser light L1. The laser light L1 and L2 are alternately made incident at 1/2F frequency respectively and the incident angle repeats a periodical variation by the theta with frequency F. The forming pattern of a small motive on the roll surface can be formed in the state of the small motive being not arranged in a straight line in the roll circumferential direction. |
