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

微机械技术作为未来工业领域的支撑和推动力，被寄予厚望，有必要促进可用于各种微型元件测量的通用测量方法和外围技术的发展，从这一点来看，认为可以利用具有微探针的小型三维轮廓测量装置作为用于此目的的测量方法。研制了一种利用隧道效应检测探针与被测物体接近程度的非接触式三维轮廓测量装置。但是，这种类型的探头的缺点是，探头只能用于导电体。本研究提出了一种用于微小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。构建了具有300 mm直径的小球透镜并连接到光纤的试验探针。探针的侧面接近电介质物质降低了通过光纤到光学检测器的反向行进光的强度。实验结果证实了光学近场效应的存在，另一方面，探测器底部靠近金属和电介质物质，增加了后向传播到光学探测器的光强。实验表明，探头与被测物之间的距离与反射光强度呈线性关系。在线性范围内，探头可用于测量物体的表面轮廓。其它实验结果也表明了非接触式光学测头的有效性。

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.