Alignment tolerances of MEMS Alvarez lenses

Characteristics and alignment tolerances of a MEMS Alvarez lens are studied. Results show that the lens can adjust its focal length substantially with small lateral displacements of its constituent elements along the x axis. Meanwhile, it is also revealed that the lens performance degrades with the increasing displacements. The lens is most sensitive to the misalignment along the y direction. Normalized RMS spot radius (NRSR) rises from 1 to 10 with a misalignment of 0.1 mm in this direction. In addition, a tilt of 1 degree about the x, y or z axis leads to a NRSR change from 0.96 to 1.02, 0.92, and 1.28, respectively.