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Expired European patentEurope

Diffraction efficiency control in holographic elements

EP 0472964 B1 · Applicant: Hughes Aircraft Company

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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 August 6, 1991 and granted December 11, 1996. A European patent lasts at most 20 years from filing, so its term ended August 6, 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 February 6, 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.
FiledAugust 6, 1991
PublishedMarch 4, 1992
GrantedDecember 11, 1996
Term endedAugust 6, 2011
Application numberEP 91113223
Classification (CPC)G03H1/18

Timeline

Timeline From EPO dates

1992199419961998200020022004200620082010Application filedAug 6, 1991PublishedMarch 4, 1992Patent grantedDec 11, 1996Term endedAug 6, 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.