Joe Guthrie

US Patent:

7548317, Jun 16, 2009

Filed:

May 5, 2006

Appl. No.:

11/418062

Inventors:

Peter Allen Sieck - Santa Rosa CA, US
Joe Earle Guthrie - Sonoma CA, US
Peter Alan Maschwitz - Sebastopol CA, US
Clive Hilton Burton - Novato CA, US
Bryan Richard Marshall - Rohnert Park CA, US

Assignee:

AGC Flat Glass North America, Inc. - Kingsport TN

International Classification:

G01N 21/55

US Classification:

356445

Abstract:

An apparatus for measuring the reflectance properties of an object having a front reflecting surface and at least one back reflecting surface. The apparatus includes a sample stage for placement of the object, a light source, a detector configured to detect reflected light from the object, and a positioning device configured to provide a plurality of angular positions for the light source and the detector relative to the object on the sample stage such that incident light on the object is specularly reflected towards the detector and the reflected light received at the detector includes a front surface reflection from the object and at least one back surface reflection from the object. The method includes illuminating the object at varying angles of incidence, collecting reflected light from the front and back reflecting surfaces of the object at respective specularly reflected angles, wavelength resolving the reflected light into a color spectrum, and analyzing an intensity of the color spectrum as a function of wavelength.