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:
Aug. 01, 2000
Filed:
Jul. 27, 1998
Shu-Ming Liu, Taipie, TW;
Primax Electronics Ltd., Taipei Hsien, TW;
Abstract
A quadrature encoding device with slope-triggered digitizing circuit is provided for use in a mechanical mouse. The quadrature encoding device is capable of producing two square-wave signals indicative of the current mouse movement for position control of the mouse cursor on the computer screen. The slope-triggered digitizing circuit includes a delay circuit and an analog comparator, which is capable of generating a first voltage output when the slope of the opto-electrical signal from the photo detector is positive, and a second voltage output when the slope is negative. It is characteristic feature of the quadrature encoding device that the output characteristic of the slope-triggered digitizing circuit would not be affected by any deviations in the output characteristic of the associated photo detectors, and also would not be affected by the ambient light. Moreover, the quadrature encoding device can operate without having to make adjustments on threshold voltage, which makes the quadrature encoding device more convenient to use, simpler in circuit complexity, and lower in manufacturing cost as compared to the prior art.