Beam-clipping-induced diffraction effects in MEMS laser scanners for autostereoscopic outdoor displays

In micro-electro-mechanical systems (MEMS) laser scanners, the beams reflected by the micromachined mirror may be truncated at various edges in the system, e.g., due to finite size of the reflective mirror surface, at the rigid supporting mirror frame, and at the package of the light source. In this paper the joint effect of such individual beam clipping is described by introducing a so-called effective system aperture. Diffraction effects induced by this virtual aperture are analyzed by means of Fourier optics incorporating the Fraunhofer far field approximation. The beam clipping theory is then applied to a laser light module with integrated MEMS mirror for autostereoscopic outdoor displays. Employing an optimization of the MEMS mirror tilting angle with respect to the laser light source, the beam-clipping-induced diffraction effects are minimized.