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Expired European patentEurope

Prism optical device and polarizer using it

EP 0474237 B1 · Applicant: SEIKO EPSON CORPORATION

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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 5, 1991 and granted March 20, 1996. A European patent lasts at most 20 years from filing, so its term ended September 5, 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 5, 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 5, 1991
PublishedMarch 11, 1992
GrantedMarch 20, 1996
Term endedSeptember 5, 2011
Application numberEP 91115031
Classification (CPC)G02B5/04 +1 more

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.