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:
Jan. 27, 2004
Filed:
Feb. 07, 2002
Applicant:
Inventors:
Assignee:
Rodenstock GmbH, Munich, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07D / ; C07D / ; G02B 5/23 ;
U.S. Cl.
CPC ...
C07D / ; C07D / ; G02B 5/23 ;
Abstract
Photochromic pyran compounds and their use in synthetic resin objects of all types, especially for ophthalmic applications, particularly spiro compounds having a fluorene structure derived from naphthopyrans, which are known as spirofluorenopyrans. By introducing respectively only one strongly electron donating or withdrawing group at specific positions in the periphery of the pyran dye, photochromic compounds obtained which in the excited state are distinguished by an expanded color spectrum, while simulataneously offering comparably good bleaching rates and good durability.