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Expired European patentEurope

Light-polarizing material based on ethylenediamine polyacetic acid derivatives

EP 0532809 B1 · Applicant: RESEARCH FRONTIERS INCORPORATED

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Overview

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Listed from its EPO record in Patent Yard's archive of European patents past their term. Its claims, description and drawings are in the EPO PDF and on Google Patents, and the Claude kit works from them.

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Why it's free to use

  • Filed September 16, 1991 and granted February 28, 1996. A European patent lasts at most 20 years from filing, so its term ended September 16, 2011.
  • A supplementary protection certificate, which can extend a medicine or crop-protection patent, adds at most five and a half years, so even that would have ended by March 16, 2017.
  • We check European rights only. A US or other national patent in its family could still be in force: check its family on Espacenet or Google Patents.
FiledSeptember 16, 1991
PublishedMarch 24, 1993
GrantedFebruary 28, 1996
Term endedSeptember 16, 2011
Application numberEP 91402451
Classification (CPC)G02B1/08 +2 more

Timeline

Timeline From EPO dates

1992199419961998200020022004200620082010Application filedSep 16, 1991PublishedMarch 24, 1993Patent grantedFeb 28, 1996Term endedSep 16, 2011

Sources & verification

Official EPO records

Full published documentClaims, description and drawings as a PDF.EPOEuropean Patent RegisterProcedure, status, file inspection and legal events.EPOLinked open EP data recordThe bibliographic record this page is built from.EPO

Cross-check elsewhere

Google PatentsFull text, worldwide family, citing patents and legal events.patents.google.comEspacenetNational family members and their legal status.European Patent Office

Everything on this page comes from the EPO record linked above. EPO data used under CC BY 4.0.