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:
Jun. 30, 1987
Filed:
Jun. 13, 1985
Koichi Ohno, Inagi, JP;
Nippon Kogaku K. K., Tokyo, JP;
Abstract
An optical apparatus for projecting a pattern on a first plane onto a second plane comprises a projection optical system disposed between the first plane and the second plane to form an imaging optical path, a structure for forming a space independent from the ambient space and filled with a gas between the first plane and the second plane in such a manner that the imaging optical path passes therethrough, the structure including a first transparent flat member perpendicular to the optic axis of the projection optical system and forming the entrance surface of the imaging light beam to the independent space and a second transparent flat member parallel to the first transparent flat member and forming the exit surface of the imaging light beam from the independent space, the gas filling the independent space having a refractive index different from the refractive index of the ambient space, and a device for regulating the distance between the first transparent flat member and the second transparent flat member and varying the thickness of the independent space in the direction of the optic axis.