Method to evaluate the enhancement of luminance efficiency in planar OLED light emitting devices for microlens array.

A method based on the variation of the area ratio of the base surface of microlenses to the light-emitting surface of the planar OLED device has been demonstrated. This method can evaluate the performance of microlens arrays with a desired geometrical shape on the improvement of the luminance efficiency for the planar light emitting devices. The maximum enhancement of the luminance efficiency of the devices in the studied microlens arrays is 56%. It is also found that the improvement of the luminance efficiency of the devices increases linearly with decreasing base length of the microlens array.