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. 11, 2007
Filed:
Jul. 22, 2004
Lawrence D. Forsythe, Milton, CA;
Lawrence D. Forsythe, Milton, CA;
Psion Teklogix Inc., Mississauga, CA;
Abstract
A control circuit to vary the intensity of an electro luminescent display. The circuit is connected between a power source and a display and comprises a pair of conductors to be connected to the display for applying a voltage from a voltage generator. A switch controls application of the voltage from the generator to the conductors. A gating circuit connects selectively one or other of the conductors to the voltage source. A controller operates upon the switch to vary the duty cycle and upon the gating circuit to alternate periodically the relative polarity of the conductors. The voltage source includes an inductor and the switch controls current flow through said inductor.