| 摘要 |
PURPOSE: To improve a luminance characteristic and durability, to prevent an erroneous lighting and to miniaturize a device in the display device of light emitting diodes driven with an AC voltage. CONSTITUTION: Respective light emitting parts 1a, 1b of a first and a second light emitting parts in which plural light emitting diodes are connected in series are connected in parallel so as to reversely biased each other and a protective circuit 2 in which a resistor and a capacitor are connected in series is connected to the parallelly connected light emitting parts in series and the AC voltage is impressed on them. The luminance of display lamps are improved and the reverse breakdown voltage of light emitting diodes is prevented from impressing by making either the first or the light emitting parts 1a, 1b emit lights even in the case of either positive voltage or the negative voltage of the AC voltage. Since the instantaneous power of the resistor is set to be low by the capacitor of the protective circuit 2 by lowering the AC voltage to a forward voltage required for light emitting of plural light emitting diodes connected in series with the resistor of the protective circuit 2, the resistor is miniaturized. |
