光学三角法实时测量金属板厚

Optical triangle method for realtime measuringthickness of metal plate

利用激光束斜入射到金属板上，在另一方向上用透镜将金属板上的激光光斑成像到光电管上。当金属板发生位移时，激光光斑的像将偏离光电管。必须用转镜将光束扫描到某一特定位置，光斑像才能进入光电管中。通过对光束扫描角度的测量，就可计算出金属板的位移量。此法也可推广到金属板的厚度测量中。由于金属板表面反射率变化会对测量带来影响，我们对此作了修正。此测量方法不但是无接触的，且不受测量对象和不利环境对传感头的影响。故可用于生产进行实时监测。

The oblique incident laser beam is projects on a metal plate,then reflected and imaged on a photocell with a lens.While the plate has a movement,the laser spot will depart from the photocell.Using a turning mirror to make the laser beam to scan a special position,the laser image spot can return to photocell.By measurement of the scanning angle of the laser beam,the displacement of the metal plate can be calculated.So the method can be applied to measure the thickness of the metal plate.In order to eliminate the influence of the variation of reflectance of metal surface,the correct method is presented.The method is no contact and can be used in real time measurements.