Patent ID: 6414751
Filing Date: 2002-07-02
Classification: G01N,G06K

Abstract:
A surface displacement detecting apparatus for detecting a surface displacement due to a concavity, a convexity or a hole in a surface of a detection object, comprising:a light shielding plate having an end portion; a light irradiating device provided at one side of the light shielding plate and to emit a light beam toward the surface of the detection object; a conveyor configured to convey at least one of the detection object and the light irradiating device relative to the other one in a conveying direction so that the surface of the detection object passes proximal to the end portion of the light shielding plate to define a gap between the surface of the detection object and the end portion of the light shielding plate, the light shielding plate being located in a direction perpendicular to the conveying direction; and a light receiving device provided at an opposite side of the light shielding device, the light receiving device having a light receiving surface to receive the light beam having passed through the gap and sense an intensity of the light beam, wherein the light beam reflected from the surface of the detection object is blocked by the light shielding plate or allowed to pass through the gap between the surface of the detection object and the end portion of the light shielding plate depending on the surface displacement of the detection object, and wherein the light receiving device is configured to receive the light beam at a different portion of the light receiving surface depending on the surface displacement of the detection object so that the surface displacement is detected based on the portion of the light receiving surface and the intensity of the light beam.