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. 27, 2004
Filed:
Feb. 27, 2002
Masashi Yanagi, Tokuyama, JP;
Nobuo Kimura, Kudamatsu, JP;
Tetsuo Andou, Kudamatsu, JP;
Hidekazu Nakamoto, Kudamatsu, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
Focusing method and exposure apparatus for focusing both a parallel light beam and a non-parallel light beam through a movable objective lens onto an object. A negative feedback loop is provided which has a detector for receiving a reflection light beam of the non-parallel light beam passed through the movable objective lens, reflected at the object and passed through the movable objective lens, for generating a detection signal corresponding to a focus deviation of the non-parallel light beam, and a driver for receiving the detection signal to control a position of the movable objective lens in accordance with the detection signal, so that the detection signal is decreased. The negative feedback loop further includes a correction signal generator for generating a correction signal and supplying it to the negative feedback loop as a disturbance of the loop so that the parallel light beam is focused onto the object.