Patent Yard Sign in
Expired European patentEurope

Interferometry

EP 0399004 B1 · Applicant: BRITISH TECHNOLOGY GROUP LIMITED

EPO PDF

Overview

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

Read the whole patent

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.

Google PatentsEPO PDF

Why it's free to use

  • Filed September 4, 1989 and granted November 17, 1994. A European patent lasts at most 20 years from filing, so its term ended September 4, 2009.
  • 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 4, 2015.
  • 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 4, 1989
PublishedNovember 28, 1990
GrantedNovember 17, 1994
Term endedSeptember 4, 2009
Application numberEP 89910144
Classification (CPC)G01B9/02094 +1 more

Timeline

Timeline From EPO dates

1990199219941996199820002002200420062008Application filedSep 4, 1989PublishedNov 28, 1990Patent grantedNov 17, 1994Term endedSep 4, 2009

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.