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:
Feb. 10, 1987
Filed:
Dec. 13, 1984
Mitsuo Tabata, Yokohama, JP;
Nobuo Shibuya, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
In a position detecting method, a light beam is radiated onto an object on which a position detecting mark is formed; the reflected beam is detected by a beam detector through a slit; the slit is vibrated, and at the same time a detection signal outputted from the beam detector is detected synchronously with the vibration of the slit; thereby detecting the position of the object. A fundamental wave component a.sub.f and a second harmonic component a.sub.2f of the detection signal are fetched due to the synchronous detection and these components a.sub.f and a.sub.2f are subjected to the conversions for eliminating the variation in output level in association with the variation in input level while the corresponding relation between the peak point of the fundamental wave component a.sub.f and the zero point of the second harmonic component a.sub.2f is held. For example, as these conversions, the following conversions are performed: ##EQU1## The output components a.sub.f * and a.sub.2f * obtained due to these conversions are used as the detection signals, and the position of the object is detected by use of these detection signals a.sub.f * and a.sub.2f *.