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:
Oct. 16, 1984
Filed:
Nov. 29, 1982
Yoshio Kawamura, Koutou, JP;
Akihiro Takanashi, Kokubunji, JP;
Toshiei Kurosaki, Edogawa, JP;
Shinji Kuniyoshi, Suginami, JP;
Sumio Hosaka, Nishitama, JP;
Tsuneo Terasawa, Kokubunji, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An automatic focusing apparatus according to the present invention is constructed of a base on which a substrate is placed, detection means for detecting a pressure of air which is caused to flow out of an interspace between the substrate and an orifice by spurting the air from the orifice toward the substrate, reference pressure generation means for generating a reference pressure which is necessary for setting a standard distance between the substrate and the orifice, a pressure transducer which receives pressure signals from said detection means and said reference pressure generation means and which converts a pressure difference between these pressure signals into an electric signal, base drive means for moving the substrate in parallel with the orifice on the basis of the output signal from said pressure transducer, and offset signal generation means for generating a signal which, when superposed on the output signal from said pressure transducer, serves to shift the substrate from the standard distance.