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. 26, 1991
Filed:
Mar. 15, 1989
Masahiro Ohishi, Tokyo, JP;
Fumio Ohtomo, Asaka, JP;
Abstract
An optical distance measuring apparatus having measurement error compensating function for compensating the measurement error due to electromagnetic induction noise which would lower the accuracy in distance measurement. According to the optical distance measuring apparatus of the present invention, the distance from the apparatus to the target is given by the difference in optical path between an 'external optical path' to a corner-cube prism, i.e. the external target, and an 'internal reference optical path'. The measurement error can be cancelled by the periodicity of the measurement error curve and the predetermined length of the optical path extension means. Thus the measurement error can be compensated for and therefore a measured distance value free of measurement error can be obtained from the distance measuring apparatus.