| 摘要 |
PURPOSE:To secure the safety of a lamp and a power source circuit by a method wherein the lamp is automatically prevented from being on when a set power which exceeds the maximum rated power of the lamp is inputted. CONSTITUTION:A comparative reference value Es is determined depending on the sum of a voltage Vs, a current Is, and a pulse width Ws, where the reference value Es is used in a comparator 20 as a comparative reference to be compared with a saw tooth wave signal of an integral circuit 26 which increases at a specified pitch. An output DE from an FF 28 is a judging signal, and even if a start pulse ST is inputted when the output DE is 'L', a lamp lightning circuit 34 is made not to operate, so that the lamp is prevented from lighting. When a set energy is larger per pulse of laser rays oscillated, the forbidden period becomes longer. When a set value of a repetition period is smaller than a certain value, a start signal is made to be generated during the forbidden period, whereby a lamp is prevented from lightning. By these processes, a breakdown of a lamp or a power source circuit trouble can prevented. |
