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. 06, 1980
Filed:
Mar. 21, 1978
Yoshio Maeda, Katsuta, JP;
Hitachi, Ltd., , JP;
Abstract
A light signal entering a photo-electric converter means is interrupted at a certain interval of time. An electrical signal produced from the photo-electric converter means, after a predetermined amount of electrical signal is added to it, is A-D converted. The difference between the digital signal associated with the interruption of light to the photo-electric converter means and the digital signal associated with non-interruption of light to the photo-electric converter means is produced, which difference is proportional to the incident light signal. Even when the light entering the photo-electric converter means is very weak, the fact that a predetermined amount of electrical signal is added contributes to A-D conversion of good linearity. Even very weak light is thus A-D converted accurately. Noises and undesirable DC signal components contained in the two types of digital signals are offset by production of the difference.