I have to invalidate the EP patent having Mar 2014 as priority date, whether the search should focus on filing date or published date of prior arts? and Can we consider a patent as prior art having filing date of Feb 2014

1 Answer 1


Prior art only needs to be dated one day before the priority date, so things dated in the previous month clearly qualify by date.

If the potential prior art is a patent application or patent that was filed before the patent in question, and subsequently published, it is prior art as of its filing date for lack of inventive step in the EPO. For lack of novelty it is prior art in the EPO as of publication date. This is different than the U.S. rules.

In most searches engines of patent data you can set a date limit so you just see things that have a qualifying date. However things published after the priority date might give you clues of keywords, inventors or authors that could lead you to earlier work.

  • Perhaps you might more explicitly state that it is the filing/priority date that matters, not the publication date.
    – Eric S
    Commented Apr 16 at 16:05
  • Thanks - in the EPO the priority date is used for novelty but the publication date is used for inventive step. Unlike the U.S.
    – George White
    Commented Apr 16 at 18:26

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