A new method of driving an AMOLED with MEMS switches

We newly propose an active-matrix organic light-emitting diode (AMOLED) pixel circuit composed of MEMS switches and its digital driving method for grayscale modulation using time ratio gray scale (TRGS) scheme. Developing a spice compatible model of the MEMS switch, the proposed driving method has been successfully verified by circuit simulation. Current driving capability of the fabricated MEMS switch is evaluated with wiring them to the OLED pixel which is separately fabricated. We could obtain the ON current of 11.4μA from the wired OLED and MEMS switch with a V
DD
of 10V. The fabricated MEMS switch with length of 50μm and width of 10μm showed the pull-in voltage of 58V and total on-state resistance (with leads) of 20 Ω. We successfully demonstrated the grayscale changes of an OLED by modulating the duty ratio of the control signal at 60Hz.