Organic electroluminescent device

摘要

An organic electroluminescent device that is capable of changing the gradation of emitted light without changing the chromaticity of the light. The organic electroluminescent device according to the present invention has an organic electroluminescent element and a drive unit. The organic electroluminescent element has a pair of electrodes and an electroluminescent layer provided between the electrodes. The electroluminescent layer contains at least two types of phosphorescent materials. Each phosphorescent material emits light the color of which is different from the color of light emitted by the other phosphorescent material. The drive unit is electrically connected to the organic electroluminescent element. The drive unit supplies to the organic electroluminescent element a current that has a modulated pulse width and a constant amplitude, thereby causing the organic electroluminescent element to emit light.