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.

Date of Patent:
Aug. 22, 1995

Filed:

Aug. 30, 1993
Applicant:
Inventors:

Hironori Takahashi, Hamamatsu, JP;

Tsuneyuki Urakami, Hamamatsu, JP;

Shinichiro Aoshima, Hamamatsu, JP;

Isuke Hirano, Hamamatsu, JP;

Assignee:

Hamamatsu Photonics K.K., Hamamatsu, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01R / ;
U.S. Cl.
CPC ...
324 96 ; 324753 ; 435808 ;
Abstract

A change in voltage can be sensitively detected at a local part of a measured object. A set of laser medium and E-O probe are disposed between a pair of mirrors, a first one and a second one, forming a laser resonator. A linearly polarized light is emitted from the laser medium. The polarized light enters the E-O probe, and returns after being reflected by the second mirror. When a voltage is given to the E-O probe from the measured object, depending on the voltage, a refractive index of the E-O probe is changed, the light emitted from the E-O probe is ovally polarized, and a resonance status of the laser resonator then varies. Therefore, the light intensity emitted through the partially penetrating first mirror to the outside of the laser resonator corresponds to the voltage at the measured object in the proximity of the E-O probe. Consequently, a voltage distribution on the measured object such as IC with fine structures can be two-dimensionally detected.


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