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:
Mar. 22, 1988
Filed:
May. 20, 1986
Toshiyuki Iwabuchi, Tokyo, JP;
Masaaki Sakamoto, Tokyo, JP;
Oki Electric Industry Co., Ltd., Tokyo, JP;
Abstract
An optical image reader includes plural pairs of switches, each pair of switches having a CMOS structure signal switch and a CMOS structure dummy switch, plural photosensing elements each corresponding to each pair of switches, plural inverters each corresponding to each pair of switches, a signal line, a dummy line, a shift register and a differential amplifier. A first switch terminal of each signal switch is connected to the corresponding photosensing element, and a second switch terminal thereof is connected to one input terminal of the differential amplifier through the signal line. A first switch terminal of each dummy switch is connected to another input terminal of the differential amplifier through the dummy line, and a second switch terminal thereof is in an open state. A first control terminal of each signal switch is connected to a first control terminal of corresponding each dummy switch, an input terminal of the corresponding inverter, and a corresponding output terminal of the shift register. A second control terminal of each signal switch is connected to a second control terminal of the corresponding dummy switch and an output terminal of the corresponding inverter. By applying a scanning pulse to each pair of switches for switching them from the shift register, an output of a photo signal and a spike noise appears on the signal line, and an output of a spike noise appears on the dummy line. These outputs are differentially amplified by the differential amplifier.