| 摘要 |
PROBLEM TO BE SOLVED: To prolong the lifetime while increasing the number of times for applying the negative voltage and effectively restoring the characteristic of the drive at OFF time by applying the alternating current voltage of a specified frequency or higher a positive electrode and a negative electrode for driving. SOLUTION: In the case of applying the forward directional direct current voltage toa positive electrode 102 and a negative electrode 106 provided in both sides of an EL light emitting zone 104, power is accumulated in an organic thin film at the time of continuous drive, and becomes a cause of deterioration of the device. On the other hand, in the case where the applied voltage is periodically changed by the alternating current driven, the current is hardly made to flow by the reverse directional voltage so that the light is not emitted, and light emission and light-out are periodically repeated, and recovery from the deterioration is performed at the OFF time. Drive frequency is desirably set at 5 kHz or more so as to increase the recovery effect and for the health of eyes of a human. Since the recover is intensively generated at the initial time of transference to OFF, pulse at 10 kHz or more is desirable for driven so as to improve the effect more, but in consideration of light emitting response time of a driven, the frequency is restricted to 1 MHz or less. |
