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Expired European patentEurope

Light valve containing an improved suspension and liquid therefor

EP 0342299 B1 · Applicant: RESEARCH FRONTIERS INCORPORATED

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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 May 20, 1988 and granted December 8, 1993. A European patent lasts at most 20 years from filing, so its term ended May 20, 2008.
  • 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 November 20, 2013.
  • 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.
FiledMay 20, 1988
PublishedNovember 23, 1989
GrantedDecember 8, 1993
Term endedMay 20, 2008
Application numberEP 88401226
Classification (CPC)G02F1/172

Timeline

Timeline From EPO dates

1989199119931995199719992001200320052007Application filedMay 20, 1988PublishedNov 23, 1989Patent grantedDec 8, 1993Term endedMay 20, 2008

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

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