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:
May. 02, 2017
Filed:
Feb. 03, 2015
Hitachi—lg Data Storage, Inc., Tokyo, JP;
HITACHI—LG DATA STORAGE, INC., Tokyo, JP;
Abstract
An optical measurement apparatus has a light source that emits a laser beam that is branched into signal light and reference light. An objective lens condenses the signal light on a measurement target to cause the measurement target to be irradiated; and a condensing position of the signal light is scanned in an optical axis direction. An interference optical system combines the signal light reflected or scattered from the measurement target with the reference light, and generates a plurality of interfering light beams having phase relationships different from one another that are detected by photodetectors. The detection signals are output as electrical signals; and a signal processing unit performs a predetermined arithmetic operation on the plurality of detection signals. The signal processing unit subtracts reflection light components from a predetermined portion of the measurement target from the plurality of detection signals or signals generated using the detection signals.