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. 27, 1991
Filed:
Jun. 12, 1990
Kiyoshi Ikuta, Kanagawa, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A distance measuring device of the dual integration type in which a signal light is projected onto an object whose distance is to be measured has light receiving means receptive of the reflection of the signal light from the object and produces two output signals of variable ratio depending on the object distance. After either or both of the two outputs have been integrated for a first integration time, an integrated value for the first integration time is reversely integrated by an output of the light receiving means different from the output or outputs which have been integrated for the first integration time, so as to measure the distance to the object by seeking a second integration time required until the integrated value for the first integration time has reached a predetermined value by the reverse integration. The present invention proposes detecting means for detecting whether or not an integration level in the first integration time has reached the predetermined value, and integration time variable means for varying the first integration time in accordance with a period of time required for the integration level in the first integration time to reach the predetermined value.