Optical method and apparatus for inspecting the front surface shape of plate shaped transparent objects

• Main Authors: KATO, MUNEHISA, KIYAMA, ATSUSHI, OTO, KIMIAKI, SONDA, YOSHIYUKI
• Format: Patent
• Language: English; French; German
• Published: 19.10.2011
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; PHYSICS; TESTING

The present invention provides an inspection method and an inspection apparatus which can remove influence of rear surface reflection image and inspect characteristic of a front surface shape with good accuracy by an inexpensive apparatus construction. First of all, as a stripe pattern suitable for a transparent plate-shaped object 3 (object to be inspected), a stripe pattern 1 having a bright-dark pattern configured so that its reflection image produced by the front surface of the transparent plate-shaped object and its reflection image produced by a rear surface of the transparent plate-shaped object are separated in an image signal obtained by image-capturing, is determined. Thereafter, the reflection image of the stripe pattern 1 produced by the transparent plate-shaped object 3 is selected and the front surface shape of the transparent plate-shaped object 3 is evaluated by an image analysis using the selected reflection image.