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:
Dec. 29, 2009
Filed:
Jul. 17, 1996
Timothy Ashley, Worcestershire, GB;
Ian Charles Carmichael, Worcestershire, GB;
Charles Thomas Elliot, Worcestershire, GB;
David George Gleaves, Worcestershire, GB;
Neil Thomson Gordon, Worcestershire, GB;
Ralph Stephenson Hall, Worcestershire, GB;
Timothy Ashley, Worcestershire, GB;
Ian Charles Carmichael, Worcestershire, GB;
Charles Thomas Elliot, Worcestershire, GB;
David George Gleaves, Worcestershire, GB;
Neil Thomson Gordon, Worcestershire, GB;
Ralph Stephenson Hall, Worcestershire, GB;
QinetiQ Limited, London, GB;
Abstract
A communications system incorporates a transmitter a receiver. The transmitter includes an infrared light emitting diode (LED). The LED output is positive or negative luminescence, i.e. above or below an equilibrium background intensity level respectively, according to the polarity of its bias signal. The receiver contains a lens to focus light from the LED onto a diode detector, from which signals pass to an amplifier, decoder and printer. Output signals from the LED have an average intensity equal to the equilibrium background intensity level and a frequency greater than 100 Hz or byte rate greater than 100 bytes/sec. They are not discernible by conventional thermal infrared imagers with frame rates of 50 Hz or less because integration in such an imager renders them indistinguishable from background.