An automatic measurement of glass thickness

Abstract This paper describes a new automatic measurement of sheet glass. The method is basically a measurement of the distance between two reflected laser beams from the top and bottom surfaces of the sheet glass, when a laser beam is directed at a fixed incident angle. This distance is converted into a time interval from scanning the laser beam at a constant velocity. In this paper we present and discuss the construction of this equipment and several factors which will have an effect on the accuracy of the measurements taken. By utilizating a microcomputer for data processing, it makes the equipment easy to maintain and highly reliable. The significant features are fully automatic, non-contact, rapid measurement time, high resolution, insensitive to vibration or wedge of the glass, etc. Because of these features this method is highly suitable for on-line measurements.