Apparatus for determining the size distribution of pigment particles in a paint surface

US5249029A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Klaus Sommer · Heidelberg, DE
• Jurgen Thiemann · Krefeld, DE
• Manfred Botzen · Krefeld, DE
• Detlef Riesebeck · Duisburg, DE

Key dates

• Filing date: Apr 30, 1992
• Grant date: Sep 28, 1993
• Expiry date: Apr 30, 2012

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N2021/5973
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The apparatus is based on a standard grindometer block comprising a longitudinally extending sample channel of steadily increasing depth which is filled with the paint to be investigated and then stripped and smoothed with a doctor blade. Instead of being visually evaluated, the paint surface is subjected to automatic objective evaluation in an optoelectronic apparatus comprising a light source with a focussing lens for producing a light spot on the paint surface to be investigated, a dark-field lens comprising an objective for picking up the scattered light emanating from pigment particles in the vicinity of the light spot and an aperture diaphragm for eliminating the light directly reflected at the paint surface, a photoreceiver connected to an evaluation circuit for detecting, recording and further processing the scattered light signals and a scanner for longitudinally scanning the sample channel.