| 摘要 |
PROBLEM TO BE SOLVED: To suppress the positional fluctuation of focus by focusing exposure laser beams on a master disk and detecting and controlling the temperature of an automatic focusing laser light emitting element. SOLUTION: The temperature of an automatic focusing laser light emitting element 1 is detected by a temperature sensor 3 and the detected temperature signals are compared with a set temperature by a thermoelectronic element controller 13. When the detected temperature is higher than the set temperature, a signal to generate heat is outputted to a thermoelectronic element 2. When the detected temperature is lower than the set temperature, a signal to absorb heat is outputted to the element 2 as a feedback signal. The element 2 has a structure in which a P type semiconductor and an N type semiconductor are coupled by metallic electrodes. The element 2 is a Peltier element that utilizes a principle in which heat is transferred by the Peltier effect. By executing temperature adjustment of heating or cooling, the temperature of the element 1 is controlled at a constant value. Thus, by adjusting the temperature of the automatic focusing laser, the fluctuation of oscillation wavelengths can be reduced and fluctuation in the focal position can be suppressed. |
