| 摘要 |
PROBLEM TO BE SOLVED: To obtain stable luminous flux in a wide range of temperatures without attaching a temperature sensor by controlling electric power for a fluorescent lamp in accordance with a voltage detected at both ends of the lamp. SOLUTION: A heater 70 is attached to the surface of a fluorescent lamp 3, while an inverter circuit 71 is connected to both ends of the lamp 3. A power source is connected to the inverter circuit 71, which controls electric power to be supplied to the fluorescent lamp 3. A heater power control circuit 75 is connected to the output of the inverter circuit 71, controlling the power to be applied to the heater 70. With a switch turned on, power is supplied to the fluorescent lamp 3 through the inverter circuit 71, lighting the lamp 3. In addition, a control signal is outputted from the inverter circuit 71 to the heater power control circuit 75, so that the power of the heater 70 is controlled. With the lamp voltage fed back, the power of the heater 70 is controlled. |
