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. 05, 1981
Filed:
Jul. 09, 1979
Citizen Watch Co., Ltd., Tokyo, JP;
Abstract
A portable electronic device with calculation and timekeeping functions, equipped with a keyboard for calculation and time setting purposes, means for producing scanning signals when a key is actuated, these signals being applied to switching elements connected to rows of keyboard contacts. When a key is depressed, the resultant high level signal potential applied to the corresponding contact row causes the row position to be detected and stored in a first memory circuit, which produces a signal causing the corresponding contact column to be detected and stored in a second memory circuit. Actuation of an external control member causes a signal to be stored by a reset signal in a first stage memory circuit which produces an output signal to be subsequently stored in a second stage memory circuit in synchronism with a timing signal. The low frequency and low duty cycle of the scanning signals and reset signal ensure minimized power consumption and suppression of switch bounce effects.