APPARATUS AND METHOD FOR INSPECTING GLASS

摘要

The present invention relates to an inspection apparatus for detecting the surface distortion in a sheet of material such as a sheet of glass, for example, and for indicating whether the level of distortion detected in the inspected sheet is unacceptable. The inspection apparatus includes a light source mounted to direct a first beam of light toward one surface of the sheet at an oblique angle of incidence to cause a second beam of light to be reflected therefrom. A light detector is mounted to receive the reflected beam and is responsive to a light pattern produced by the reflected beam of light for generating an output signal representing the width of the light pattern. The width of the light pattern is a function of the surface distortion of the portion of the surface from which the beam is reflected. A control circuit is responsive to the detector output signals for generating an actual distortion signal representing the amount of surface distortion in the inspected portion of the surface. In the preferred embodiment of the invention, a plurality of individual actual distortion signals are generated and are utilized by the control circuit for generating an overall distortion signal representing the overall distortion in the inspected sheet. The overall distortion signal is compared with a reference distortion signal which defines the acceptable level of surface distortion. Based on the comparison, an indicator is provided for indicating whether the inspected sheet is unacceptable.