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:
May. 16, 1989
Filed:
Apr. 03, 1987
Applicant:
Inventors:
Paul Derner, Gelsenkirchen, DE;
Peter Reichmann, Gelsenkirchen, DE;
Assignee:
Flachglas Aktiengesellschaft, Furth, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
E04B / ; E06B / ;
U.S. Cl.
CPC ...
52171 ; 381 731 ; 381191 ;
Abstract
An anti-eavesdropping window structure in which the inner and outer panes, separated by a spacer frame have thickness d and D such that D/d is at least equal to 1.5. The space between the panes is filled with a gas mixture having a density in excess of that of air and a body-sound generator applied directly to the outer pane generates thermal noise over a frequency range of 200 to 3000 Hz to superimpose a level of such noise of at least 20 dB on transmitted sound.