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. 28, 1988
Filed:
May. 27, 1986
Applicant:
Inventors:
Kiichiro Nishina, Tokyo, JP;
Taira Kouchiwa, Kanagawa, JP;
Assignee:
Ricoh Company, Ltd., Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ; G02B / ;
U.S. Cl.
CPC ...
350470 ; 350464 ;
Abstract
A plastic lens assembly for use in a copying machine is a four-element configuration or a six-element configuration. The lens assembly has an aperture stop and is completely symmetrical with respect to the aperture stop. With the four-element lens assembly, all of the four lenses are made of plastics. Where the six-element lens design is employed, at least second through fifth lenses are made of plastics. The lens assembly are designed to sufficiently reduce variations in the focal length which would otherwise be caused by varying temperature and humidity.