| 摘要 |
A laser power control system (150; 150') having a first pulse stretch capability, as may be used in a rapid prototyping system (100), is disclosed. According to one disclosed embodiment, a one-shot multivibrator (156) generates a pulse responsive to a gate signal (LON/LOFF) indicating that the laser (110) is to be turned on. The pulse, which is of a selected duration suitable for achieving population inversion, is applied to the laser (110); upon the end of this pulse, pulse-width-modulation (PWM) control of the laser begins. According to another disclosed embodiment, a first pulse stretch store (166) retains a digital value corresponding to the duration by which the first PWM pulse is to be lengthened; adders (176; 178) add this digital value to the parameters indicated by the desired laser power signal (DLP) to ensure population inversion and laser output of the laser (110) in the first pulse. |
