Development of optical probe for shapes and dimension measurement of micro-parts

微机技术作为一项将成为未来有发展前景的工业领域的支撑和推动力的技术，已经产生了巨大的希望，有必要促进可用于各种类型微元件测量的通用测量方法和外围技术的发展。从这个角度来看，可以利用微型探针的小型三维轮廓测量仪作为测量方法。研制了一种非接触式测头利用隧道效应探测被测物体接近度的三维轮廓测量仪。但是，这种探针的缺点是；这种探头只能用于电导体。本研究提出了一种用于微零件形状和尺寸测量的光学微探头，并进行了探头的研制和测量实验。制作了一个直径为300毫米的小球透镜，连接到光纤上的试验探头。探头侧面靠近介电物质降低了通过光纤向光探测器反向行进的光的强度。实验结果证实了光学近场效应的存在。另一方面，探头底部靠近金属和介电物质，增加了向光学探测器反向行进的光的强度。实验表明，探头与被测物体之间的距离与反射光强呈线性相关。在线性范围内，探头可用于测量物体的表面轮廓。其他实验结果也证明了非接触式光学探头的有效性。

Micro-machine technology has engendered great hopes as a technology that will be the support and driving force of promising industrial fields in the future It is necessary to promote the development of the general purpose measurement method and peripheral technologies that can be used in the measurement of various types of micro components.From this point of view, it is thought that a small three-dimensional profile measuring apparatus with micro-probe can he utilized as the measuring method for this purpose. The three-dimensional profile measuring apparatus, which has non-contact probe detecting proximity to measuring object through tunneling effect, has been developed. But, the drawback of this type of probes; the probes can be used only for electric conductors.In this research an optical micro-probe for shapes and dimension measurement or micro-parts has been proposed, and development of the probe and measuring experiments were carried out. A trial probe that has a small ball lens diameter of 300 mm, connected to an optical fiber was built. Proximity of flank of the probe to the dielectric substances decreases the intensity of the backward traveling light to an optical detector through the optical fiber. The result of the experiments confirms the optical near field effect.On the other hand, proximity of bottom of the probe to the metallic and dielectric substances increases the intensity of the backward traveling light to the optical detector. This experiment show, the distance between the probe and the measuring object and reflected light intensity is linearly correlated. In the linearity range, the probe can be used for measurement of the surface profiles of the objects. Also the validity of the non-contact optical probe is shown by other experimental results.