Device and method for measuring the thickness of a transparent sample

US7554678B2 · kind B2 · utility

Assignee

• ISRA SURFACE VISION GMBH · DE

Inventors

• Ulrich Pingel · Marl, DE
• Stefan Leute · Herten, DE
• Paul Weigt · Bochum, DE

Key dates

• Filing date: Dec 22, 2004
• Grant date: Jun 30, 2009
• Expiry date: Jun 14, 2025

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B11/06
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The invention relates to device for measuring the thickness of a transparent sample (2), particularly a glass strip or a glass pane, involving the use of: a first light beam (L1), particularly a first laser beam, which strikes upon the front surface (8) of the sample (2) at a first angle of incidence (α1); a second light beam (L2), particularly a second laser beam, which strikes upon the front surface (8) of the sample (2) at a second angle of incidence (α2), the first angle of incidence (α1) and the second angle of incidence (α2) being different, and; at least one detector (11, 12) for detecting the light beams (L1′, L1″, L2′, L2″) of the first and second incident light beams (L1, L2) reflected by the sample, and for determining the position thereof. In order to also be able to carry out a correction for curvature, at least one incident light beam (L3), which is essentially parallel to the first or second light beam (L1, L2), is oriented toward the front surface (8) of the sample (2), and at least one detector (11) is provided for detecting a light beam (L3′) of the parallel light beam (L3) reflected by the sample (2) and for determining the position thereof. The invention also re…