| 摘要 |
PROBLEM TO BE SOLVED: To supply driving current and a timing condition most suitable to the characteristic of an organic EL and to lengthen the life of the organic EL by regularly switching forward bias voltage and backward bias voltage generated in a constant voltage source at a constant period to oscillate square waves by constant current. SOLUTION: Voltage signals from a forward bias constant voltage source 6 and a backward bias constant voltage source 7 are inputted in a switch circuit 8, and supplied to an organic EL 5 through a current detecting circuit 9. The current value supplied to the organic EL 5 is measured with the current detecting circuit 9, inputted in a control circuit 11, compared with an operating condition value set with an operating condition setting circuit 10, a new voltage value and a switching period are set, and control signals are sent to the forward bias constant voltage source 6, the backward bias constant voltage source 7, and the switch circuit 8. By comparing the newest current value for every period, the organic EL 5 can always be driven with a suitable current value and wave form. |
