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Expired European patentEurope

A photomask for, and a method of, producing semiconductor devices

EP 0051402 B1 · Applicant: FUJITSU LIMITED

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Overview

The published document from the EPO: abstract, claims, description and drawings. Open it full size

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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 22, 1981 and granted April 25, 1984. A European patent lasts at most 20 years from filing, so its term ended October 22, 2001.
  • 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 22, 2007.
  • 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 22, 1981
PublishedMay 12, 1982
GrantedApril 25, 1984
Term endedOctober 22, 2001
Application numberEP 81304970
Classification (CPC)G03F1/50 +1 more

Timeline

Timeline From EPO dates

1982198419861988199019921994199619982000Application filedOct 22, 1981PublishedMay 12, 1982Patent grantedApril 25, 1984Term endedOct 22, 2001

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.