| 摘要 |
PROBLEM TO BE SOLVED: To immediately light a cold-cathode fluorescent tube without changing the control of the voltage fed to it by providing an auxiliary light source means irradiating the fluorescent tube with light energy on a lighting means feeding the voltage for lighting the fluorescent tube sealed with gas. SOLUTION: The AC voltage converted with the DC voltage from a DC/DC converter 10 by a DC/AC inverter 11 is fed to a cold-cathode fluorescent tube 14 storing rare gas and mercury. The voltage Vi detected and converted with the current between electrodes 15 by a tube current detecting circuit section 30 is smaller than the reference voltage determined by the resistors R2, R3 of a lighting switch section 31 immediately before lighting when no current flows after the AC voltage is fed. The light of an auxiliary power supply such as a light emission diode LED emitting light when switching elements Q2, Q1 are turned on is applied to a cold-cathode fluorescent tube 14 to generate an easily ionizable state of gas. A current flows between the electrodes 15 after lighting, the voltage Vi becomes larger than the reference voltage, and the switching elements Q2, Q1 and the light emission diode LED are turned off. |
