| 摘要 |
PURPOSE:To extend the life of a cooling object part like a semiconductor laser by providing a sensor which senses the atmospheric temperature in the vicinity of the cooling object part, a humidity sensor, and a second temperature sensor which detects the temperature of the cooling object part and setting the temperature value based on the saturated vapor pressure to control cooling. CONSTITUTION:A first temperature sensor 12 and a humidity sensor 13 which detect the temperature and the humidity of the atmosphere around an optical head 2 (cooling object part) are arranged in the vicinity of the optical head 2, and a first set temperature generating part 15 generates a first set temperature value ts1, which is obtained by adding a prescribed temperature value ta to a temperature value te at which a vapor pressure value (e) of the atmosphere is equal to the saturated vapor pressure, in accordance with inputted first detected temperature value ts1 and detected humidity value td. A second temperature sensor 14 which detects the internal temperature of the optical head is buried in the optical head 2, and a cooling control part 16 operates the function in accordance with the result of comparison between the inputted first set temperature value ts1 and an internally generated second set temperature value td2. Thus, accurate cooling is possible, and the life of the cooling object part such as an element used at a high temperature is extended. |
