微小高度检测系统设计

Design of projection optical system of the solder joint height detection device

高度信息是分析物体三维形貌的最重要信息。为了研究微小焊点的三维形貌,需要对焊点高度进行测量。针对传统测量技术的缺点,设计了一种检测系统。系统应用白光平行照射条纹板,将其像投影到被测物体上,受到物体高度轮廓的调制作用,形成变形的亮暗相间的条纹。该条纹图携带着焊点的三维信息,再用照相系统把变形的条纹图拍摄在CCD上,通过对CCD上像的处理,可以还原出高度信息。该方法可将条纹板的像等间距地投射到被测物体的表面上,避免了由于投影条纹宽度不同所带了的图像处理过程的误差。实现了测量范围大、重复性好、图像处理简单的优点,为微小高度的测量提供了新方法。

Height information is the most important parameter in analysing an objectrs threedimensional morphology. In order to study the three-dimensional topography of small solder joints, the height of solder joints needs to be measured. In overcoming the shortcomings of traditional measurement techniques, a new detection system was designed. The system applies white parallel light exposure stripes board, projects its image onto the tested object. With the modulation of the object height profile, a distorted bright-dark stripe was formed. Whose fringe pattern carried the three-dimensional information of the solder joints and the distorted fringes were then shot on to the CCD by the camera system. Through processing the CCD image, the height information could be restored. Uniformly-spaced images of the striped panels projected onto the measured object surface were realized by this method, the image processing errors caused by the projection stripes of different widths were avoided. The advantages of the system include large measurement range, good reproducibility, simple image processing, etc. providing a new way for small height measurement.