Imaging Proximity Sensor and a Transducer for Rapid Automated Determination of Surface Quality and Surface Defects

摘要

The surface quality transducer allows the quantitative determination of characterization of surface profiles and defects, independent of the surface's optical or magnetic properties. The transducer is capable of quantitatively determining local and average surface roughness as well as depth and size of surface flaws. In the capacitive proximity sensor, a two-dimensional array of small capacitive sensors detects the distance between each sensor tip and the target object. When touching the surface or operating at close distance, an image of the surface is obtained. Both transducers employ capacitive gauging because of the method's high sensitivity for the measurement of small distances. Each capacitive sensor consists of a thin short lead (line capacitance) embedded in a hard ceramic substrate. The sensors are rugged and can be configured to almost any desired shape to examine even hard-to-reach surfaces. In both transducers, an electronic circuit converts the capacitance variations into voltage signals that are sampled by a microcomputer. The microcomputer controls the measurement operation, and processes, stores, and displays the incoming data.