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:
Mar. 14, 2006
Filed:
Feb. 08, 2005
Tomokazu Masubuchi, Osaka, JP;
Kohtaro Hayashi, Toyonaka, JP;
Shigeru Sawamura, Osakasayama, JP;
Konica Minolta Opto, Inc., Hachioji, JP;
Abstract
A projection optical system includes from the enlargement side a first lens unit, a mirror which is an optical path bending member, a second lens unit, and a third lens unit. The projection optical system is designed so that a condition (1), 5.5<T/FL<12.0, is fulfilled. Here, Tis the air equivalent distance between the first lens unit and the second lens unit, and FL is the overall focal length of the projection optical system. By fulfilling the condition (1), it is unnecessary that the diameter of the first lens unit be extremely large. It is also unnecessary to change the lens shape to prevent interference between the first lens unit and the second lens units, so that an increase in the cost of the projection optical system can be suppressed.