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:
Feb. 13, 1990
Filed:
Apr. 15, 1988
Gerd Ulbers, Weilersbach, DE;
Hommelwerke GmbH, Schwenningen, DE;
Abstract
A laser optical apparatus for measuring the distance between the apparatus and a measuring surface which comprises an optical measuring reflector on said measuring surface, a converting transformer for converting the position of said reflector into corresponding electrical signals and an indicator for said signals. The improvement comprises a first optical interferometer having a measuring wave guide coupled with a reference wave guide and a second optical interferometer also having measuring and reference wave guides. The length of the second measuring wave guide is different from the length of the second reference wave guide and a computer is used to compare output electrical signals the value of which depend upon this difference. The apparatus also includes a device to correct the wave length of the laser beam by controlling the electrical current to the laser.