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:
Jul. 12, 1988
Filed:
Jan. 08, 1987
Tetsuo Kimura, Tokyo, JP;
Nittan Co., Ltd., Tokyo, JP;
Abstract
A separation type light blocking smoke detector detects smoke present between a light emitting section and a light receiving section spaced therefrom by detecting blocking of light between the light emitting section and the light receiving section. The detector includes a light emitting section driving circuit, a counting circuit, and a storage circuit. The light emitting section driving circuit changes the emission intensity of the light emitting section in accordance with a predetermined changing mode for every repetitive cycle. The counting circuit includes a first comparator and an updating signal generator, and counts a physical amount corresponding to a period during which an output from the light emitting section falls in a predetermined range for each repetitive changing cycle. The storage circuit includes a second comparator and an AND gate, and stores a count value of the counting circuit in an arbitrary repetitive cycle. The count value stored in the storage circuit and that from the counting circuit are compared by a third comparator.