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:
Sep. 21, 1999
Filed:
Apr. 23, 1998
Edouard Da Silva, Lille, FR;
Michel Delhaye, Villeneuve D'ascq, FR;
Michel Leclercq, Bois le Roi, FR;
Bernard Roussel, Valenciennes, FR;
Dilor, Lille, FR;
Abstract
In an optical fittering device comprising at least two fitters, the first filter (EF1) is tilted by an angle of incidence whose value is adjusted to bring the cut-off limit of the first filter (EF1) closer to one of the sides of the line of the illumination beam (FLA), which reduces the optical density of the first filter, while the association in series of the first (EF1) and second (EF2) filters enables to obtain a high-pass filtering whose global density corresponds to the sum of the densities of the first and second filters and whose cut-off limit is lower than that obtained by a single filter tilted to its optimum angle. A third filter (EF3) mounted in parallel with respect to the first and second filters (EF1 and EF2) enables to obtain, at the level of the common collection path (TCC), a band eliminating filtering whose cut-off limits are positioned on either side of the illumination line with a view to an optimum analysis of the low frequency lines.