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:
Feb. 26, 1991
Filed:
Sep. 11, 1989
National Research Council of Canada, Ottawa, CA;
Abstract
Apparatus for nondestructive detection of subsurface defects in a continuously moving workpiece of sheet material by using an infrared thermal imager. The temperature of a portion of the surface of sheet material is altered and the presence of subsurface flaws is indicated by development of discontinuities in the surface temperature distribution above the defects. In order to avoid problems due to changes in the infrared emissivity of the surface of sheet material, such as caused by grease patches or oxidized areas as well as errors caused by reflections of other sources of infrared radiation from the surface, the thermal image of the portion is first transferred by contact to a surface of a thermal transfer device whose surface has a high infrared emissivity and a low infrared reflectivity. Then the thermal image of the portion is obtained from the surface of the thermal transfer device.