Structural Parameter Analysis And Experiment Of MEMS-based Grating Moving Light Modulator

Projection display device is undergoing a period of muti-development, and MEMS-based microdisplay device as an important branch has promoted the next generation display industry for its merits. But domestic research on these devices is relatively lagged and restricted by international patents, so it is a great importance and potential value to develop a novel microdisplay device with independent intellectual property rights. In this paper, a MEMS-based Grating Moving Light Modulator is proposed after the review of literature in domestic and abroad is summarized, its theoretical model is developed and validated by diffraction experiment and the characteristics and structural parameter of the device is analyzed and simulated. Finally, the gap between the upper surface of movable grating and underling reflector is measured by wavelength scanning experiment. The main work of this thesis includes:①Electromechanical model is developed based on principle of parallel plate, and two optical models are developed according to description of optical transmission function of GMLM, the relationship between pull-in voltage, resonance frequency, diffraction efficiency, contrast ratio and geometrical parameters of GMLM is achieved, which is in line with the result of simulation.②According to structure parameter analysis and fabrication condition of the device, its performance specifications are as followings: diffraction efficiency 15.6%, contrast ratio 2946.5, operation voltage 3.9V, pull-in voltage 5V and resonance frequency 2.41MHz.③Combining with simulation by CoventorWare, the methods of using different thickness of grating margin, foursquare electrode, laddering electrode and thinner cantilever can increase the optical active area from 50% to 60%, 70%, 75%, 85% respectively.④Diffracted experiment of GMLM is done, and the distribution of diffraction intensity, achieved from diffraction pattern by digital image process, is consistent to theoretical result, and the optical model with cantilever's influence is more available.⑤The gap between the upper surface of movable grating and underling reflector is measured by wavelength scanning experiment, comparing with the result measured by WYKO Laser Interferometer, the error of demodulated result is about 0.8%, furthermore, the next experiment for measuring pull-in voltage, resonance frequency...