I apologize for the click bait title, but that's really my question.

35 USC § 102(a)(2) provides:

A person shall be entitled to a patent unless—

(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.

Claiming priority is valid if one inventor is the same (plus a few more things) according to the relevant paragraph.

If the priority is not valid for any claim x because the claim is not sustained by the old description, this could mean a valid priority for the patent application and the priority document being prior art for the obviousness of claim x.

Wouldn't that make claiming with a different inventor (and one that's the same) a mad gamble?

Or to put it into practical terms, shouldn't an additional inventor for an application that's supposed to claim priority reiterate if their contribution was actually enough to merit inventorship because it might kill claim x, even if they only contributed to claim y?

  • Why would the priority document be prior art? If it's a provisional, it's only made public when the non-provisional is published. If it's a non-provisional or overseas application, it's published 6+ months after the Convention application must be filed. So neither of these situations seems fatal. Am I understanding the situation properly?
    – Maca
    Jan 8, 2018 at 21:17
  • I also edited the question to quote the section I think you were referring to. Hopefully I got it right.
    – Maca
    Jan 8, 2018 at 21:19
  • @Maca mpep 901.03 “a U.S. patent application publication under 35 U.S.C. 122(b) is considered to be prior art as of the earliest effective U.S. filing date of the published application“ - they are prior art effectively from the filing date / basically backwards in time if published later, or not? And thx, that was exactly the section I meant.
    – user18033
    Jan 8, 2018 at 21:38

1 Answer 1


Consider the following scenario:

Prov1 - Filed on 1 July 2016

NP1 - Filed on 1 June 2017, claiming priority to Prov1

NP2 - Filed on 1 July 2017, claiming priority to Prov1

Once NP1 is published, it is prior art as of 1 July 2016 (the filing date of Prov1). So if a claim of NP2 does not have a valid priority claim to Prov1, it must be novel/non-obvious over NP1.

However, 35 USC § 102(b)(2)(A) provides:

Disclosures appearing in applications and patents.—A disclosure shall not be prior art to a claimed invention under subsection (a)(2) if—

(A) the subject matter disclosed was obtained directly or indirectly from the inventor or a joint inventor;

That is, if an inventor of NP2 is also an inventor of NP1, then NP1 cannot be prior art.

This is analysed at MPEP § 2154(02)(a):

Thus, if the subject matter in a U.S. patent document upon which the rejection is based is by another who obtained the subject matter from the inventor or a joint inventor, the applicant may establish by way of an affidavit or declaration that a disclosure is not prior art under AIA 35 U.S.C. 102(a)(2).

So I do not believe there should be any harm caused by the situation you note.

  • Interesting. So a joint inventor is enough for priority. I had this question because in Europe, in theory, you should be able to destroy novelty with a priority document if it doesn't sustain the claims but discloses them (e.g. saying that something isn't part of the invention in the priority doc)
    – user18033
    Jan 8, 2018 at 21:59
  • Are patents (published) by the same inventor prior art by 102 a (1) or does 102 b (2) A mean that no patent publication by a joint inventor is prior art?
    – user18033
    Jan 8, 2018 at 22:04
  • @DonQuiKong Correct, though it may still be relevant for double patenting.
    – Maca
    Jan 8, 2018 at 22:11
  • @DonQuiKong a priority document cannot destroy novelty unless it is published by some way. This may either be that the priority document ends up in a normal filing and is thus published, or that it is simply part of the file open to public inspection. You are not reading G 1/15 decision, are you? Jan 9, 2018 at 7:00
  • @chempatent1981 sure, but the moment you claim priority it will be published. And for us purposes, the publication is deemed to have been made on the filing date. Same in the eu for novelty. I'm not, but now I will ;). I was actually thinking about applications where a prior own application is critical for novelty (but not the same invention) and if claiming priority would work as an argument for “it's either not destroying novelty or a valid priority“. In one of those edge cases where there's a critical sentence that might be problematic for novelty but doesn't fit into a claim.
    – user18033
    Jan 9, 2018 at 7:11

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