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:
Apr. 07, 1998
Filed:
Jul. 24, 1995
Taro Itatani, Tsukuba, JP;
Tadashi Nakagawa, Tsukuba, JP;
Yoshinobu Sugiyama, Tsukuba, JP;
Kimihiro Ohta, Kashiwa, JP;
Abstract
An apparatus of measuring an electric signal comprises a laser device, optical elements, an electrooptic crystal, a photoelectric converter, and an electric circuit. The electrooptic crystal is selected from the materials in the type of having properties of changing its refractive index in the direction of its optic major axes and the direction of these axes by a function of an applied electric field. In the apparatus, the electrooptic crystal is placed in the electric field applied by an electric circuit under measurement. A laser beam emitted from the laser device is incident on the electrooptic crystal. A reflected light passed through the crystal is resolved into rays in two polarized direction. Each ray is subjected to a photoelectric conversion by passing through the photoelectric converter and exerted as an electric output. A differential signal of the electric output is defined as a measurement signal. By selecting two polarized directions of the laser beam by a half-wave plate as the optical element, two signals corresponding to the changes in the refractive index and optic major axes of the crystal. Two component of a vector of the electric field can be obtained by a first order combination of these signals.