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.

Date of Patent:
May. 23, 2000

Filed:

Dec. 24, 1997
Applicant:
Inventor:

James A Ringlien, Maumee, OH (US);

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01N / ; G01N / ; G01J / ; H01L / ;
U.S. Cl.
CPC ...
356240 ; 356 73 ; 356239 ; 356365 ; 250223 ; 2502081 ; 250225 ;
Abstract

Infrared and visible light energies are directed through a container onto a CCD camera that is responsive to both the visible and infrared light energy. Crossed polarizers are positioned on opposed sides of the container, and operate on the visible light energy in such a way as to block transmission of visible light to the camera in the absence of stress variations in the container, which alter polarization of the visible light energy traveling through the container. On the other hand, the polarizers have little or no effect on the infrared light energy, which creates a normally gray intensity of background light at the camera. In this way, incidence of visible light on the camera due to stress variations in the container appears as a bright signal against a normally gray background, while blockage of infrared light due to opaque variations in the container appears as a dark signal against the normally gray background.


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