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:
Jul. 11, 2000
Filed:
Feb. 27, 1998
Tadahiko Hoshi, Tokyo, JP;
Masahiro Nakamura, Yokohama, JP;
Nikon Corporation, Tokyo, JP;
Abstract
Optics-based inclination measuring apparatus (10) for measuring an inclination angle .theta. relative to the horizontal. The apparatus includes a lens (20), a light source (30), a sensor (34) having one or more sensor sections, and a container (40) having a non-opaque near-wall (44). The container contains a liquid (54) having a free surface (60). A light beam (80) from the light source passes through the lens, through the non-opaque container wall and reflects off the free liquid surface. The light beam then passes back through the lens and impinges on the sensor, forming an image, such as a spot image. The location of the spot image on the sensor depends on the inclination angle of the inclination measuring device. Signal ratios from the sensor sections are used to determine the relative location of the spot image and hence the inclination angle.