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:
Jul. 27, 2021
Filed:
Feb. 28, 2020
Seiko Epson Corporation, Tokyo, JP;
Hirotaka Yanagisawa, Azumino, JP;
Eiji Morikuni, Matsumoto, JP;
SEIKO EPSON CORPORATION, Tokyo, JP;
Abstract
A projection optical system has first and second optical systems disposed in order from a demagnification side toward a magnification side. An intermediate image is formed between demagnification-side and magnification-side imaging surfaces. The second optical system is an optical element having first transmission, reflecting, and second transmission surfaces in order from the demagnification toward the magnification sides. The first transmission and reflecting surfaces are located at one side with respect to an optical axis. The second transmission surface is located at the other side with respect to the optical axis. The reflecting surface has a concavely curved surface shape. The second transmission surface has a convexly curved surface shape protruding toward the magnification side. The optical element has a first member and a second member different in refractive index from the first member. A bonding surface between the first member and the second member has a curved surface shape.