Thin film thickness measurement method and apparatus

Abstract From the Canadian patent

Techniques for non-contacting thikness or caliper measurments of moving webs or sheets employ a sensor device that includes a first sensor head and a sencond sensor head that are spaced apart to define a path through which the moving web travels. The sensor device projects a laser generated multiple , points pattern onto the upper surface of the monving web. Pattern recognition algorithm analysis of the pattern identifies the orientation e.g.tilt, of , the moving web. The device further measures the film tilt,the distance between the first sensor head and the first web surface the distance between the , second sensor head and the second web surface and the distance between the , two …