Patent ID: 6111649
Filing Date: 2000-08-29
Classification: G01B

Abstract:
A thickness measuring apparatus comprising:a light source for emitting obliquely a slit-like light ray on a major surface of a light-transmittable layer of an object which comprises said light-transmittable layer and a non-light-transmittable layer;an image pick-up device for receiving a first reflection slit-like light ray reflected from said major surface of said light-transmittable layer of said object and a second reflection slit-like light ray reflected from a surface of said non-light-transmittable layer and outputting first and second video signals relating to said first and second reflection slit-like light rays, respectively;an analog-to-digital converter for converting said first and second video signals into first and second digital image data;a position detecting section for integrating said first and second digital image data along a longitudinal direction of said first and second reflection slit-like light rays, and calculating first and second barycentric positions of said integrated first and second digital image data in a width direction of said first and second reflection slit-like light rays, respectively, said calculated first and second barycentric positions corresponding to positions of said major surface of said light-transmittable layer and said surface of said non-light-transmittable layer of said object, respectively; anda first thickness calculating section for calculating a thickness of said light-transmittable layer of said object on a basis of said position of said major surface of said light-transmittable layer and said position of said surface of said non-light-transmittable layer.