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:
Sep. 05, 2000
Filed:
Aug. 25, 1998
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A light intensity control apparatus includes an optical beam splitter which splits light into monitor light and principal light; a polarization beam splitter which splits the monitor light into two polarized light components; a monitor light detector which detects the polarized light components; a polarization correction device which corrects the output of the monitor light detector so that the intensity of the output signal of the monitor light detector and the light intensity of the principal light on an object surface have a predetermined correlation, regardless of the polarization state of the light incident upon the optical beam splitter; and a humidity dependency correction device which corrects the output of the monitor light detector via the polarization correction device by detecting a variation in polarization dependency characteristics of the optical beam splitter, caused by a change in humidity, and feeding the variation back to the polarization correction device, so that the output signal intensity of the monitor light detector and the light intensity of the principal light on the object surface have a predetermined correlation, regardless of a change in the humidity. The invention is also directed to a light intensity control method.