Large-scale autostereoscopic outdoor display

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

“…Compared to the non-optimized tilting anglę = 45 • of the first-generation prototype, the maximum fast axis divergence angles max {Â 0,y } of the clipped beams are reduced by 8%, 2%, and 2% for the red, green, and blue beams, respectively. Since the maximum 3D viewing distance of the autostereoscopic outdoor display is inversely proportional to the fast axis divergence angles [3,4], this optimization of the MEMS mirror tilting angle ˛ increases the maximum 3D viewing distances by the same factors. , the field f(x,y) directly after the effective system aperture p(x,y), and the field of the diffracted beam g(x,y) after a propagation distance d sufficiently large to fulfill the Fraunhofer approximation constraints as a function of the normalized transversal coordinate y for ˛ = 38.75 • and ˇ = −10 • .…”

“…1. Since the maximum distance at which a viewer can perceive the autostereoscopic effect is directly related to the fast axis divergence angle [4], the analysis in the following is limited to this spatial dimension.…”

“…MEMS laser scanners consist of a laser light source with one or more laser diodes emitting light of usually different wavelengths, collimation optics, and at least one onedimensional (1D) or a single two-dimensional (2D) scanning MEMS mirror, which are capable of deflecting the collimated light beams in one or two spatial dimensions. These scanners are employed in a variety of different display applications, such as flying spot pico projectors [2], large-scale autostereoscopic outdoor displays [3][4][5], head-up displays [6], and retinal scanning displays [7]. Other applications range from confocal microscopy [8] and optical coherence tomography (OCT) [9] to light detection and ranging (LIDAR) [10], laser printers [11], bar code readers [12], and optical cross-connects [13].…”

“…As an example, the beam clipping theory is then applied to a laser scanner for autostereoscopic outdoor displays [3][4][5]. Fig.…”

“…For many applications the quality of the scanned laser beams is crucial, e.g., for autostereoscopic outdoor displays where the divergence angle of the collimated laser beams is the most important system parameter since this optical parameter is directly related to the maximum distance at which a viewer can perceive the stereoscopic effect [3][4][5]. The major optical limitations of MEMS laser scanners are the static and dynamic flatness of the scanning mirror as well as the clipping of the reflected beam, e.g., due to the finite size of the reflective surface.…”