Flying vision system of placement machine for MEMS microphone
Liguo Chen, Zhu Jifeng, Weibin Rong, Lining Sun · 2010
In the die bonding process of MEMS microphone chip, the exact center and rotate angle of MEMS microphone chip is corrected after the vacuum nozzle has adsorbed it. In order to achieve high speed and precision placement function, the flying vision system based on rotating mirror is proposed, the mirror is driven to rotate by the power drawn from the nozzle rise and fall movement through a rack and pinion mechanism, the nozzle pick and place functions is not interfered by mirror through designing the rack and pinion mechanism parameters. The vision system can capture an static clear MEMS chip image when the mirror rotated to a 45 degrees position referenced with horizontal position, the center position and rotating angle of MEMS chip is fast calculated by the fine and coarse Hough Transform Algorithm, the center location and angle will be corrected by the control system during the mounted head is flying to placement position. The experimental results show that the system can obtain high-quality MEMS microphone chip image, the chip's center position and rotating angle correction algorithm takes no more than 0.1s, so it can meet the high-speed placement requirements. In this proposed flying vision system, mechanical structure is simple and compact, MEMS chip's image is clear without distortion, and there is no restriction on the mounted head movement trajectory. The flying vision system significantly enhances the quality and efficiency of SMD Chip; it can be widely used in the surface mounted system.