Study On The Application Of Microlens Arrays Film For OLED

With the"4C"—computer, communication, consumer electronics, car electronics and the"3G"(the third generation mobile phone) coming, CRT, LCD, PDP and LED display technology have been unable to meet the more and more requirements of the information for display devices. In particular, it will transmit large amounts of information and images through the flexible body in the future. Organic light-emitting device (OLED) is regarded as the potential next-generation lighting and display devices due to the advantages of thin, lightweight, self emission and flexible.However, due to waveguiding phenomena in the anode/organic layers and the substrate, the low out-coupling efficiency becomes the main limitation on applications of OLED. Therefore, how to improve the out-coupling efficiency of OLED without affecting the radiation spectrum becomes a hot research topic.In this paper, the out-coupling efficiency enhancement of OLED attached with microlens arrays film on the glass substrate is studied. Firstly, a ray trace method is used to simulate the performance of OLED attached with microlens arrays film of different shape and arrangement. The microlens arrays are fabricated by combining digital micro-mirror device (DMD) based parallel photolithography and photoresist thermal reflow method. Microlens arrays film is finally obtained using electroplating and UV imprinting techniques. Then, the microlens arrays films are attached on the glass substrate of OLED respectively, the luminance of devices is measured, and the out-coupling efficiency enhancement factor is calculated by comparing the output luminance of the device with and without the microlens arrays film. Both the simulation and experimental results show that the out-coupling efficiency of OLED attached with microlens arrays film is improved. The luminance in normal direction of OLED attached with a spherical microlens arrays is experimentally improved by maximum 42%; with the elliptical microlens arrays, the directional out-coupling efficiency is improved, the simulation results show that the viewing angle difference of half intensity between the major axis and the minor axis is up to 30°.Finally, the subject of this study is summarized, and point out what can be done in the future work.