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:
Jul. 27, 1982
Filed:
Sep. 22, 1980
Fred Mast, Wil, CH;
Gretag Aktiengesellschaft, Regensdorf, CH;
Abstract
A measuring head for a densitometer comprises a light source and an optical system for forming a spot of light of defined size on the surface of an object under test. The optical system guides the reflected or transmitted light, depending on the type of densitometer, from the area of the spot to a photoelectric measuring transducer. The light intensity distribution across the spot as seen by the transducer is weighted to have a bell-shaped curve with its maximum at the center of the spot. The weighting may be done in the optical path from the spot area to the transducer or, as described, in the path between the source and spot area by means of a filter comprised of a plano-convex transparent lens and a plano-concave lens of neutral grey glass. The lenses have the same index of refraction and the same curvatures and are joined to form a plane parallel plate having a maximum transmissivity on its axis, the transmissivity decreasing radially from the axis. The head finds particular use for measuring raster-like material such as offset printing.