| 摘要 |
PROBLEM TO BE SOLVED: To improve luminance and light-emitting efficiency, and to lower a discharge maintaining voltage, in a light source for outdoor/indoor lighting, display or a liquid crystal display backlight. SOLUTION: A first voltage V1 having a first frequency is impressed on an electrode 21, in order to let a discharge device discharge itself. In addition, a second voltage V2 having a second frequency higher than the first frequency is superposed on the first voltage V1. The waveform of the voltage having the second frequency may be a damped waveform synchronized with the first frequency. Electrons, ions, or plasma existing in the discharge formed previously are vibrated accompanying electric field changes due to this voltage superposition. If the second frequency is selected appropriately, further resonance of electrons, ions and plasma occur, due to which the temperature of the particles rises. Thereby, the electron temperature becomes close to a value preferred for irradiation of visible rays or ultraviolet rays, which improves light-emitting efficiency. |
