Jun-o Kim

Gimbaled 2D Scanning Mirror with Vertical Combs for Laser Display

We designed a gimbaled 2D scanning mirror (GSM) which is driven electrostatically by vertical comb fingers. The horizontal scanning mirror with a diameter of 1 mm is rotating with respect to y-axis in the eye-shaped frame. For vertical scanning, the eye-shaped frame is rotating with respect to x-axis which is perpendicular to the horizontal scanning axis. This GSM can be actuated in two axes simultaneously resulting in the realization of 2D image in the screen with single beam raster scanning. We obtained a mechanical scanning angle of plusmn8deg(resonance) and plusmn4.2deg(non-resonance), with the resonant frequency range of 24~24.5 kHz and 800~900 Hz under the sinusoidal and triangular driving voltages for horizontal and vertical scanning, respectively

Slow Scanning Electromagnetic MEMS Scanner for Laser Display

A small size, low power consuming, shock proven optical scanner with capacitive comb type rotational sensor for the application of mobile projection display was designed, fabricated, and characterized. To get a 2-dimensional video image, the present device horizontally scans a vertical line image made through a line-type diffractive spatial optical modulator. In order to minimize device size as well as power consumption, the mirror surface was placed on the opposite side of the coil actuator. To prevent thermal deformation of the mirror, the mirror was partially connected to the center point of the coil actuator. For shock proof, mechanical stoppers were constructed in the device. The scanner was fabricated from two silicon wafers and one glass wafer using a bulk micromachining technology. The packaged scanner consists of the scanner chip, a pair of magnets, yoke rim, and base plate. The fabricated package size is 9.2mmx10mmx3mm (0.28cc) and the mirror size is 3mmx1.5mm. The scanner chip has no damage under the shock test with impact of 2,000G in 1ms. In case of full optical scan angle of 30° at 120Hz driving frequency, linearity and power consumption are measured 98% and 60mW, respectively, which are suitable for mobile display applications.