The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 13, 2006
Filed:
Sep. 28, 2004
Applicant:
David W. Johnston, Kensington, NH (US);
Inventor:
David W. Johnston, Kensington, NH (US);
Assignee:
Osram Sylvania Inc., Danvers, MA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01J 4/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
An LED polarimeter is described which is suitable for measuring the stress in photoelastic materials. The polarimeter comprises a sequential arrangement of an LED light source, a first polarizer, a ¼ wave plate, and a second polarizer substantially aligned along a central axis. The relatively monochromatic LED light source essentially eliminates errors caused by chromatic abberations and heat damage to the polarizing film. Preferrably, the LED light source emits in the green region of the visible spectrum to take advantage of the sensitivity of the human eye to this part of the spectrum.