GMLM (Grating Movable Light Modulator)is a novel light modulator based on MOEMS technology which can be used
in fields of display and print. But present design has only 30% effective diffraction area, which can deeply influence the
key parameters such as pixel-filling-ratio and contrast. An electromechanical model of the device was established, and
the effective spring constant of GMLM was deduced by energy method. According to that the relation between structure
parameters and effective diffraction area was analyzed theoretically. Then optimized structures were simulated and
validated by FEM software Coveter Ware. Simulation data shows that the optimization device model can enhance the
effective diffraction area to about 90% from less than 30% before optimization.
In this paper, a 27um×27um novel grating light modulator supported by cantilevers has been presented, and it can be fabricated using silicon surface-micromachining technology. The structure and basic operation principle of grating light modulator is introduced. The structure is composed of grating plate, address electrode and four cantilevers, the grating plate, which is supported by four cantilevers placed around, is overhung about one wavelength of incidence light from the underlying address electrode, it is actuated like a piston by electrostatic force, and piston-type motion of grating can be used to modulate phase of incident light, therefore, the grating light modulator array is a potential device for projection displays and relevant devices for its intrinsic characteristics. Mechanics model is developed for deducing the deformation equation, the relationship between the electromechanical characteristics of the device and the geometrical parameters and material performance is analyzed, such as pull-in voltage, resonance frequency and step response time. Electromechanical coupled simulation is done by Coventorware, then, more reasonable geometrical parameters are obtained for fabricated in the next step.