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:
Oct. 07, 1997
Filed:
Jul. 12, 1995
Hitachi, Ltd., Tokyo, JP;
Abstract
A physical quantity measuring apparatus in which the measurement range of the physical quantity such as displacement, pressure or the like can be widened. Laser beams different in wavelength are radiated through an optical fiber onto a diaphragm and the light reflected on the diaphragm and the light reflected on a reference face opposite to the diaphragm are returned to the optical fiber so that the distance between the reference face and the diaphragm which is transformed, and hence a pressure difference, is measured by a light interference method. The quantity of displacement of the diaphragm is measured optically by using laser beams different in wavelength from each other so that it is possible to make the measurement accuracy high and to effect measurement in a wide range with respect to a physical quantity such as displacement, pressure, or the like, without being influenced by a change in characteristic of the optical fiber.