Industrialization of Non-contact-type Probe for Three-coordinate Measurement

近年来，工业领域中经常使用三坐标测量机，它们大多采用接触式球头进行位置检测。然而，对于曲面、体积很小或易变形的物体，需要使用非接触式探头来测量其尺寸。因此，我们开发了一种基于立体视觉方法的新型非接触式测头，可以检测X、Y、z方向的位置。在本研究中，我们的目标是开发一种实用的非接触式探头，具有重量轻、体积小、自动检测功能和精度好的特点。结果总结如下：1。采用本文提出的由一对物镜、CCD相机和高亮度led作为光源组成的光学系统，设计并试制了一种非接触式探头。试制了一种图像处理单元，用于叠加两幅图像并显示双重图像，人工测量的精度为0.1-0.6 μ m，具有标准偏差的重复性。对于z轴位置的自动检测，图像处理单元与三坐标测量机的计算机相连。提出了一种提高z位检测精度的新原理，并编制了相应的计算机程序。在图像处理单元中增加了自动检测X和y位置的功能。提出了一种提高X、y位置检测精度的新原理，并开发了包括z位置在内的位置自动检测的计算机程序。对于IC引线框架的实际测量，达到了足够的精度。测量精度：x位0.11 μ m， y位0.21 μ m， z位0.1 μ m。

Recently, the three-coordinate measuring machines are often used in the field of industry, and most of them use contact-type ball probe for detecting position. However, non-contact-type probe has been required to measure the dimension of the object which has curved surface, is very small in size or is easy to deform. So, we have developed a new non-contact-type probe which can detect X-, Y- and Z-position based on the stereo-vision method.In this study, we aim to develop a practical non-contact-type probe which has features of light weight, small size, automatic detection function and good accuracy.Results are summarized as follows :1. A non-contact-type probe which employs the newly proposed optical system consisting of a pair of object lenses, CCD cameras and high luminance LEDs as light sources, is designed and on trial produced.2. An image processing unit to superpose two images and to display the double image is on trial produced and the precision of the manual measurement is 0.1-0.6 mum for repeatability in standard deviation.3. For the automatic detection of the Z-position, the image processing unit is connected with the computer of the three coordinate measuring machine. A new principle which improves the detective accuracy of the Z-position is proposed, and the computer program is developed.4. The function for the automatic detection of the X- and Y-position is added to the image processing unit. A new principle which improves detective accuracy of the X- and Y-position is proposed, and the computer program for the automatic detection of position including the Z-position is developed.5. Sufficient accuracy is achieved for practical measurement of the IC lead frame. The precision of measurement is 0.11 mum for X-position, 0.21 mum for Y-position and within 0.1 mum for Z-position, in standard deviation.