Method and apparatus for contactless optical measurement of the thickness of a hot glass body by optical dispersion

US7414740B2 · kind B2 · utility

Assignee

• Schott AG · DE

Inventors

• Thorsten Wilke · Nack, DE
• André Witzmann · Waldershof, DE
• Rupert Fehr · Mitterteich, DE
• Johann Faderl · Nieder-Hilbersheim, DE
• Otmar Schmittel · Hamm, DE
• Ernst-Walter Schaefer · Welgesheim, DE
• Christopher Fritsch · Mainz, DE

Key dates

• Filing date: Jul 13, 2005
• Grant date: Aug 19, 2008
• Expiry date: Jul 13, 2026

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B2210/50
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The method measures the thickness of a hot glass body without direct contact with the glass body and is based on chromatic aberration. This method includes focusing a light beam from a light source on the hot glass body using a focusing device immediately after formation; conducting reflected light from the glass body into a spectrometer to obtain a reflected light spectrum; finding two wavelengths of the reflected light from the front side and the rear side of the glass body respectively at which reflected light intensities are maximum; determining the thickness of the glass body from the difference between the two wavelengths; maintaining the focusing device at a temperature below 120° C. during the measuring of the thickness and substantially preventing heat radiation from reaching the focusing device using at least one heat-blocking filter.