I am a co-inventor together with a fellow engineer. Some time ago, we filed a provisional for our invention and close to 12 month later, in coordination with the co-inventor, I filed a PCT application where we are both listed as co-inventors (let's call this PCT1).

However, I later noticed that my co-inventor's business partner had also filed a PCT application for this invention but listing only my friend as the sole inventor (let's call this PCT2). PCT2 was filed one day after PCT1.

There is no disagreement among us that we are both inventors and both conceptually contributed to the invention. PCT2 describes much of my work and even uses some graphs that I had created as part of the figures.

I am concerned now that both applications (i.e. also the legitimate PCT1 application) get rejected on grounds of double patenting. What can I do?

Can I mount an inequitable conduct claim and invalidate PCT2 without affecting PCT1?

  • PCT1 should be safe. Are any claims of PCT2 encompassing your part of the invention? If not, they are within their rights (from a patent law standing, contracts between you might apply) apart from maybe copyright issues on your graphs which wouldn't affect the patent.
    – user18033
    May 19, 2019 at 12:08
  • @DonQuiKong I think it’s best if you’d turn your comment into a full fledged answer.
    – Eric S
    May 19, 2019 at 16:28

2 Answers 2


Double patenting results when the right to exclude granted by a first patent is unjustly extended by the grant of a later issued patent or patents.The doctrine of double patenting has been created to prevent the unjustified extension of patent exclusivity beyond the term of a patent.

The following criteria are considered for the issue of double patenting, two or more patents or applications must have at least one common inventor, common applicant, and/or be commonly assigned/owned or non-commonly assigned/owned but subject to a joint research agreement.

Since the doctrine of double patenting seeks to avoid unjustly extending patent rights, the focus of any double patenting analysis necessarily is on the claims in the multiple patents or patent applications involved in the analysis.

As the criteria of atleast one common inventor is satisfied in your case you can expect a provisional statutory double patenting rejection if the second filed application is directed to the same invention.

If any the claims of PCT2 has your concept or your contribution you have to be named as a joint inventor, if so you could file an Inequitable conduct representation at USPTO.

The court has held that “[c]onception is the touchstone of inventorship,” each joint inventor must contribute to the conception of the invention. Burroughs Wellcome Co. v. Barr Lab., Inc., 40 F.3d 1223, 1227-28 (Fed. Cir.1994). There is no requirement that the conception be of equal magnitude though. Indeed, it is not necessary for each inventor to contribute conception to all of the patent claims filed in order to be joint inventor. It is enough for one to contribute conception to a single claim in order to be considered a joint inventor. See SmithKline Diagnostics, Inc. v. Helena Lab. Corp., 859 F.2d 878, 888 (Fed. Cir. 1988). Thus, if one contributes to the conception of something – indeed anything – that winds up being claimed in a patent application they are joint inventors (or co-inventors as they are sometimes referred to).

This article in IPwatchdog in conclusion described the following

1.An inventor is someone who came up with the idea for the invention? 2.An inventor is someone who diligently works on making the invention?

The answer to question 1 is, yes, if and only if the person who came up with the idea contributed conception. The idea in and of itself is not enough. After all, having an idea that it would be wonderful to travel back in time does not make one an inventor of a time machine.

The answer to question 2 is, yes, if and only if the person who diligently worked on making the invention (i.e., reducing the invention to practice) actually contributed conception to at least one of the patent claims.

Kindly check your contribution in the PCT2 claims before making any representations.

Please take an attorney opinion as they would be in a better position in identifying the best way out.

  • 2
    Also, the PCT application and its claims are not as material as the claims actually pursued in individual national stage proceedings. The PCT2 claims can be amended in each location after the PCT search etc.
    – George White
    May 24, 2019 at 1:05

This may be a problem. Inventors are required when filing to make an Oath or Declaration. If the OoD is incorrect it could result in an invalidation of the application. If you both participated on the invention but only one person is listed then the OoD would be imperfect and may be thrown out.

37 CFR 1.41 Applicant for patent.

(a) An application must include, or be amended to include, the name of the inventor for any invention claimed in the application.

(b) The inventorship of a nonprovisional application under 35 U.S.C. 111

(a) is the inventor or joint inventors set forth in the application data sheet in accordance with § 1.76 filed before or concurrently with the inventor's oath or declaration. If an application data sheet is not filed before or concurrently with the inventor's oath or declaration, the inventorship is the inventor or joint inventors set forth in the inventor's oath or declaration, except as provided for in §§ 1.53(d)(4) and 1.63(d). Once an application data sheet or the inventor's oath or declaration is filed in a nonprovisional application, any correction of inventorship must be pursuant to § 1.48. If neither an application data sheet nor the inventor's oath or declaration is filed during the pendency of a nonprovisional application, the inventorship is the inventor or joint inventors set forth in the application papers filed pursuant to § 1.53(b), unless the applicant files a paper, including the processing fee set forth in § 1.17(i), supplying the name or names of the inventor or joint inventors.

  • This is a U.S.-only answer for an international question. There is no oath or declaration involved with a PCT application. Also, the USPTO does not directly police the accuracy of declarations and, as other answers have pointed out, the claims that emerge in the national stages of the PCT2 may/should, only cover material with no conceptual contribution by the person who is not listed as an inventor.
    – George White
    Jul 1, 2019 at 17:45
  • My comment was primarily directed at US inventors; however, this applies in a variety of other contexts. The EPO likewise requires a designation of inventor. Failure to accurately file can result in the revocation of a granted patent. In most cases the court is the venue of reconciliation for these matters--not the respective patent office itself.
    – Patently
    Jul 4, 2019 at 1:26

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