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:
Jun. 02, 1998
Filed:
Dec. 13, 1996
Kei Aimi, Hirakata, JP;
Yasushi Mukai, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
Inputs output beams of a laser that have been oscillation-frequency modulated by an injection current control by a power source into a beam splitter through a lens and an isolator, detects beams reflected from a first half-mirror and passing through a path, beams reflected from a second half-mirror and passing through a path, and beams reflected from an object to be measured and passing through a path, with a photodetector, detects a beat frequency signal according to an optical interference of the above-described three types of reflected beams with a frequency detector, and calculates a distance to the object to be measured from the three beat frequencies with a signal processing unit. Can measure the distance in high precision by erasing a change rate of the oscillation frequency modulation and speed of light and by eliminating an influence of fluctuations, based on information of the three frequencies. Also, includes means using a lens for carrying out reflection and transmission on both sides of the lens instead of using the first and second mirrors and includes means using a polarization splitter and a 1/4 wave plate instead of using the beam splitter.