| 摘要 |
PROBLEM TO BE SOLVED: To reduce a manufacturing cost by providing a device with a light quantity sensor detecting the light quantity of a fluorescent lamp and a heater covering the surface of the fluorescent lamp except an irradiating direction and keeping the temperature of the fluorescent lamp set in a standby state. SOLUTION: The circumferential surface of the fluorescent lamp 43 is provided with the heater 51. Then, a slit-like aperture part 52 is formed at the heater 51 extending over a range being almost identical to the irradiation range of the lamp 43. The heater 51 is closely brought into contact with the surface of the lamp 43 except the aperture part 52 so that the tube wall of the lamp 43 can be heated. Since the heater 51 is arranged by being closely brought into contact with the circumferential surf ace of the lamp 43 in such a way, heat can be properly transmitted to the lamp 43 from the heater 51. On the other hand, the light quantity sensor 55 for detecting the quantity of light emitted from the lamp 43 is fitted to a side reflection plate 48. Then, the light quantity of the lamp 43 detected by the sensor 55 is converted to an electric signal and inputted to a control means so as to be used for adjusting the light quantity of the lamp 43. Thus, the light quantity of the lamp 43 is stably maintained. |
