AR/VR/MR systems challenge projector systems to increase their refresh rates, resolutions, and Field of View (FOV). Projecting a 1080p image with a 100Hz frame rate by a Laser-Based Scanner (LBS) projector necessitates a very fast MEMS scanning mirror (with a scanning frequency of over 100kHz). Designing and manufacturing such MEMS devices for raster scan mode is extremely challenging, yet to be achieved. As a result, Lissajous scanning mode was suggested, presenting an improved pixel coverage of the FOV with relatively lower frame rates. Nevertheless, even with reduced frame rates, the additional challenge raised by using Lissajous scan mode with existing laser drivers switching times. At such scan rates, a pixel ‘on’ time is about 2.5ns. For common 200MHz lasers drivers, this implies a horizontal jitter of about +/-0.5 of a pixel. Addressing the challenges of projecting HD with MEMS mirrors, a new paradigm enabling to project of HD video using a feasible MEMS scanning mirrors technology is suggested by using interlaced raster scan mode.

Interlace raster projecting allows using a MEMS mirror with a much lower scanning frequency (of a few tens of kHz) while having improved pixel coverage of the FOV. At such scanning rates, the pixel jitter level goes to 0.05 of a pixel for a 200MHz laser driver. Moreover, the interlace projection allows increasing the vertical resolution on the expanse of the frame rate. However, using interlacing with ramp scan mode for the vertical scan could affect the non-uniformity of pixel coverage due to line crosshatching. The same phenomenon is observed in Lissajous scan mode. The presented new paradigm suggests an interlace raster projection, with parallel lines of each projected field, with low vertical jitter. For this purpose, the slow vertical ramp motion is replaced with a fast stepped motion for each projected line. Maradin presents a novel MEMS mirror controller applying the interlace scan approach to enable the extreme requirements of the AR/VR/MR displays.