In this article we present a new large aperture 1D-MEMS scanner module especially designed for laser radar systems. The scanner module has a resonance frequency of 250 Hz and optical scan range of 60°. It comprises of two separate scanning channels: (a) a single scanning mirror of the collimated transmitted beam oscillates parallel to (b) a scanning mirror array of the receiver optics. The receiver optics use a synchronized array of 2 x 7 identical mirror elements, each with 2.51x 9.51 mm² per single mirror element, resulting in a total aperture of 334 mm² and filling factor of 80 %. We discuss in detail the system integration of the MEMS components including packaging and synchronized operation of all scanner elements to guaranty a large aperture of the LIDAR receiver optics. In addition the paper includes a conceptual discussion of optical design and expected S/N ratio and measurement range of final LIDAR system. It will be shown that the presented new concept of MEMS based LIDAR system can realize also high accuracy of the distance measurement similar to state of the art TOF-LIDAR scanners enabling a new generation of miniaturized, robust and potentially cost efficient LIDAR systems due to the MEMS technology
This contribution presents an optical module for projection of still images and video sequences. It consists of a laser source, miniature collimator optics, and a special MEMS device, a two-dimensional resonant micro scanning mirror. The laser beam is focused onto the micro mirror by the collimator optics. The micro mirror reflects the beam onto the desired projection area with a flare angle of up to 15 degrees for both axes. Given the resonant oscillation of the mirror, the beam follows a Lissajous figure. By choosing appropriate oscillation frequencies, it can be ensured that the laser beam hits every pixel of a pre-defined geometrical image resolution at a given frame rate. Limitations result from mechanical stability of the mirror plate that has a typical diameter of 1 mm and the CMOS-compatible fabrication process of the MEMS device. Projection of images and video sequences is achieved by modulating the laser diode. An external electronics receives data and transforms it into necessary modulation signals. Since frequency and amplitude of oscillation of the micro mirror are highly precise, no electrical feedback from the mirror to the modulation electronics has to be implemented. The system can be operated in open-loop modus. Currently, a monochrome demonstrator with VGA (640 x 480 pixels) resolution and 50 frames per second has been realized. Because of the compact size of the mirror, integration into mobile devices is fairly easy
Recently, there has been substantial progress in the development of ultracompact image projection systems. This has been enabled by the availability of electrically modulated laser sources for all three elementary colors and a 2D resonant microscanning mirror as a micro-opto-electro-mechanical system (MOEMS) device for light deflection. The laser beam formed by collimator optics is directed onto the micro-scanning mirror. Given the movement of the mirror, the laser beam scans the entire image area. By driving the mirror and electrically modulating the intensity of the laser beam in a synchronous manner, a projection of images can be achieved. In this contribution, we present the theoretical background of the projection system as well as the latest achievements in system design. Both monochrome and full-color systems are currently available. The latter uses a separate laser bank as an RGB light source, which is coupled with a projection head. For monochrome red systems, the laser diode can be integrated into the projection head as well, whose volume can be reduced to 15×7×5 mm. All systems have video graphics array (VGA) (640×480 pixels) resolution and operate with 8-bit color depth per pixel and 50 frames per second
Laser projection has been realized using a 2d micromechanical scanner mirror. For handheld devices it is advantageous to compensate motion. This can be realized using inertial sensors for motion detection and the implementation of a compensation algorithms. The projector must provide sufficient dynamic range for the compensation. A demo system was realized and tested successfully.
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