Micro-motion measurement system for milli-structure using diffraction grating

摘要

Current technological development toward miniaturization requires smaller components. These components usually generate complex multi-DOF motions other than simple 1-DOF motion. therefore it is essential to develop measurement methodology for 6-DOF motions. In this paper, a new 6-DOF measurement system for milli-structure is presented. This methodology basically employs the Optical Beam Deflection Method (OBDM) with a diffraction grating. A aser beam is emitted toward the diffraction grating which could be attached on the surface of a milli-structure and the incident ray is diffracted in several directions. Among these diffract4ed beams, 0th and +-1th order diffracted rays are detected by 4 Quadrant Photodiodes. From coordinate values from each detector, we can get information for 6-DOF motions with linearization method. Required resolutions for milli-structure measurement are sub-micrometer in translation and arcsec in rotation. Experimental results indicate that proposed system has possibility to satisfy this requirement. This method can be applied to measurement of various applications such as arm head of HDD, micro positioning stages.