Analysis of Optical Collecting System for MEMS-based Grating Moving Light Modulator

Grating moving light modulator, a MEMS-based movable diffraction grating with electrostatic actuation, can be used for projection displays and relevant applications, its dominant power exchange is between the 0
^th
and plusmn1
^st
order by modulating phase of incident light, two optical collecting systems based on 0
^th
, plusmn1
^st
order operation are designed and analyzed with Fraunhofer diffraction theory and Fourier transforms optics, the latter is more available with theoretical performance of imaging system: optical efficiency eta=30.6%, contrast V=1225, comparing with the simulation results by Coventorware: eta=29.5%, V=740, the decrease results from the warp of the device when pulled down by electrostatic force