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. 09, 2000
Filed:
Dec. 01, 1997
Kazuya Kamon, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
In a projection printing apparatus, illumination light from a lamp housing illuminates a photomask, and a diffracted light beam from the photomask is focused on an exposed substrate via a projection optical system to project a circuit pattern, the projection optical system including first and second halfmirrors and first and second concave mirrors. The first and second halfmirrors are arranged in symmetry or similar symmetry with respect to a normal to an optical axis of a diffracted light beam directed from the first halfmirror to the second halfmirror. Thus, a projection printing apparatus and a projection printing method are obtained in which unevenness in transmissivity in the projection optical system can be compensated for and steric hindrance or degradation of image characteristics is not caused.