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. 19, 1984
Filed:
Feb. 09, 1982
Robert N West, Chislehurst, GB;
Andrew J Barker, Orpington, GB;
Sira Institute Limited, , GB;
Abstract
Test apparatus and method for testing for faults in, for example, transparent sheet material in which two parallel beams of light separated by a distance 'w' are passed through a grating having, for example, light transmitting and absorbing areas separated by a distance 'w', so that as the two beams are scanned across the object and the grating the light output through the grating is generally constant. If, however, there are faults which displace one beam with respect to the other, then the spacing between the beams will change so the light output will vary from the norm. Furthermore, if there is a fault which would cause attenuation of the two beams, then the light output will again vary from the norm.