| 摘要 |
PROBLEM TO BE SOLVED: To enhance a jitter characteristic by reducing an average light quantity of a laser beam by a pulse train during only a period excluding a prescribed time after rising of a pulse of a pulse signal for controlling the intensity of the laser beam in an exposure process and a prescribed time before falling of the pulse. SOLUTION: The laser beam emitted from a laser beam recorder driven and controlled by a pulse signal T0 to a photoresist film fixed by baking the film formed on the surface of a master glass glass disk is controlled. The prescribed times Th and Tt after rising and before falling of the pulse signal T0 respectively are made to be two to four times as long as a basic clock T, and the other period of time is modulated by the pulse train of a shorter period than the basic clock T to reduce the average light quantity. Then, the pulse signal T0 is generated by a control circuit using an AND circuit, a NAND circuit and signal generator and inputting an original signal of pulse width T0 and a signal delayed by the time Th and Th+Tt. Consequently, the jitter characteristic is enhanced. |
