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. 20, 2008
Filed:
Apr. 04, 2006
Tien-min LU, Taipei Hsien, TW;
Tien-Min Lu, Taipei Hsien, TW;
Zippy Technology Corp., Hsin-Tien, Taipei Hsien, TW;
Abstract
A keyboard without ghost keys has a circuit which includes a microprocessor in which a plurality of I/O lines form a keyboard scanning matrix. Two of the I/O lines on the matrix cross to define a plurality of signal switches. The microprocessor is electrically connected to a primary level resistance and a reference potential to determine the ON condition of the signal switches. Each signal switch further is electrically connected to at least one secondary level switch which is electrically connected to the primary level switch in a serial manner. When a user depresses any three signal switches on the rectangular angles of the keyboard scanning matrix, the connecting primary level resistance and the secondary level resistance form a new level resistance. The new level resistance and the current flowing to the keyboard scanning matrix are processed to get a potential smaller than the reference potential, thereby to eliminate the phenomenon of ghost keys.