| 摘要 |
PURPOSE: To improve luminous efficiency of a device so as to reduce power consumption, by superposing the second voltage, having the second frequency higher than the first frequency, in addition to the first voltage having the first frequency as the voltage applied to an electrode. CONSTITUTION: In order to emit light from a discharge tube 20 of a discharge device, the first voltages V1, V2 are applied to electrodes 21, 22 from drive voltage generating circuits 23, 24 having the first frequency. Further the second voltage is applied to be overlapped with the first voltage from drive voltage generating circuits 25, 26 having the second frequency higher than the first frequency. A voltage waveform having the second frequency may be a damped waveform. By overlapping this voltage, an existing electron and ion or plasma formed in the discharge tube are vibrated according to changing an electric field. When the second frequency is suitably selected, further also a resonance phenomenon or the like of the electron, ion and plasma is generated. In this way, an electron temperature is made adjacent to a value preferably for radiating visible light or ultraviolet rays, to improve radiation efficiency. |
