基于体视显微镜的三维显微表面测量系统

Three dimensional micro surface measurement system based on stereomicroscope

将条纹投影轮廓测量术和体视显微镜相结合,搭建了一套能够对微小器件的表面三维形貌进行测量的系统。该系统由一台Greenough型的体视显微镜,一台DMD投影仪,一个CCD相机和一个机械平移台组成。在利用相移算法和降级去包裹算法得到被表面形貌调制过的无歧义相位后,通过相位和高度的映射关系,得到高度值,从而能够对微小器件的表面形貌进行重建。在标定时,通过精密的机械平移台将陶瓷标定板置于不同的高度,对其进行相位测量,得到多组相对应的相位和高度值,再对每个像素点进行多项式拟合来确定相位和高度的映射关系。实验测量了标定的最后一个平面以及微型的球栅阵列,平面测量结果显示测量误差在10μm以内,从微型球栅阵列的三维重建结果可以清晰地看到排列的球形结构。实验结果证明了该系统对于平面和复杂的三维结构都能够进行精确的测量。

Combining fringe projection profilometry and stereomicroscope, a system is setup which can measure three-dimensional topography of micro devices. This system consists of Greenough-type stereomicroscope, projector, CCD camera and mechanical translation table. After unambiguous phase is obtained by using phase shift algorithm and descrambling method, which is modulated by surface topography, height value is obtained by phase and height mapping relationship, so that surface morphology of micro devices can be reconstructed. At the time of calibration, ceramic calibration plate is set at different heights by means of a precision mechanical translation table, and several groups of corresponding phase and height values are obtained. Then polynomial fitting of each pixel is performed to determine phase-height mapping. Last calibrated plane and micro ball grid array are measured. Results show that measurement error is within 10μm, and spherical structure is clearly seen from three-dimensional reconstruction of micro-ball grid array. It is proved that system can accurately measure both planar and complex three-dimensional structures.