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. 12, 2004
Filed:
Aug. 19, 2002
Applicant:
Inventors:
Takayuki Nakano, Tokyo, JP;
Yasuhisa Tamagawa, Tokyo, JP;
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G03B 1/00 ; G02B 2/742 ;
U.S. Cl.
CPC ...
G03B 1/00 ; G02B 2/742 ;
Abstract
A field flattener having a function of flattening a bent image surface on which an image is formed through an optical system, is composed of a material of which a refractive index is equal to or larger than 2. A sectional configuration of the field flattener cut in an optical-axis direction containing the optical axis is formed to take a stepped shape toward its peripheral edge from the optical axis. An axial height of the stepped portion configuring the surface in the optical-axis direction in this stepped shape is set so as to equal to or larger than twice a wavelength of beams to be used.