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Expired European patentEurope

An apparatus for driving a fluorescent light by periodically changing the applied DC polarity.

EP 0537394 B1 · Applicant: Yang, Tai-Her

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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 October 17, 1991 and granted June 23, 1999. A European patent lasts at most 20 years from filing, so its term ended October 17, 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 April 17, 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.
FiledOctober 17, 1991
PublishedApril 21, 1993
GrantedJune 23, 1999
Term endedOctober 17, 2011
Application numberEP 91309568
Classification (CPC)H05B41/2928

Timeline

Timeline From EPO dates

1992199419961998200020022004200620082010Application filedOct 17, 1991PublishedApril 21, 1993Patent grantedJune 23, 1999Term endedOct 17, 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.