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. 07, 1995
Filed:
May. 17, 1993
Hiroyuki Kawashima, Tokyo, JP;
Fumio Ohtomo, Tokyo, JP;
Susumu Saito, Tokyo, JP;
Isao Minegishi, Tokyo, JP;
Kabushiki Kaisha Topcon, , JP;
Abstract
An absolute length measuring apparatus comprising light sources, a beam splitter, an object of measurement, a scanning mirror, a light receiver, sampling parts and a distance measuring part. The light sources emit alternately a plurality of coherent light beams having different wavelengths. The beam splitter splits the coherent light beam from the light sources into two optical paths. The object of measurement is located on one of the two optical paths stemming from the beam splitter. The scanning mirror is located on the other optical path stemming from the beam splitter and made movable in the direction of optical axis. The light receiver receives both the reflected light beam from the object of measurement and the reflected light beam from the scanning mirror through the beam splitter. The sampling parts generate sampling signals of various wavelengths by sampling the output of the light receiver every time the light sources emit a coherent light beam while scanned by the scanning mirror. The distance measuring part assumes a synthetic wavelength signal having a wavelength sufficiently greater than any individually generated wavelength based on the phase relations of the sampling signals, and measures the distance to the object of measurement in accordance with the synthetic wavelength signal.