Priority claim contained in data sheet and appended via certificate of correction validMay 15, 2008

In a decision yesterday, the Federal Circuit vacated a district court's denial of a preliminary injunction. The district court denied the injunction on the basis of a substantial question of validity of the patent. The accused infringer alleged the patent was invalid under 35 U.S.C. § 102(b) based on a prior public use by the patentee, and argued that created a substantial question regarding the validity of the patent. The patent issued from an application that included a reference in the application data sheet to a provisional application with identical specification and claims, although the reference did not initially appear on the face of the issued patent, but was instead added via a certificate of correction. The patentee initially did not dispute the critical date used by the accused infringer (which was based on the nonprovisional filing date), but later realized the proper critical date should be based on the provisional filing date, and pointed this out to the district court. The earlier priority date would prevent the asserted public use from being a statutory bar. The district court held there was a substantial issue regarding whether the patent was entitled to the priority date, in the main because the patentee had initially not contested the accused infringer's assertion regarding the applicable critical date.

The Federal Circuit vacated. The court noted it was undisputed that the accused infringer was aware of the provisional application, and a copy of the patent (and the certificate of correction adding the reference to the provisional application) was attached to the complaint. Counsel for the patentee conceded not raising the issue earlier was an "oversight," and the court held that in such a situation, it was improper for the district court to have found a substantial question of validity based on the patentee's failure to raise the issue earlier in the preliminary injunction proceedings. The court then addressed the merits of the accused infringer's assertion that the patent was not entitled to the provisional application's priority date, finding them to be without merit. As a result, the Federal Circuit held the patent was entitled to the earlier priority date, vacated the denial of the injunction, and remanded the case for the district court to consider whether a preliminary injunction is appropriate in light of the correct priority date.

DuPont owns a patent entitled "Process for making a flexographic printing plate and a photosensitive element for use in the process." The application that led to the patent was filed February 27, 2002, and the application data sheet included with the application included the following statement:

Continuity Data: This application is a non-provisional of provisional 60/273669 2001-03-06 WHICH IS PENDING.

The two applications had the same specification and claims, although the provisional listed one inventor whereas the nonprovisional listed five inventors, one of which was the inventor from the provisional application. When the patent issued on August 10, 2004, it did not have a reference to the nonprovisional on its face, so DuPont sought a certificate of correction, which issued on July 26, 2005.

DuPont sued MacDermid for infringement in April 2006, and moved for a preliminary injunction shortly thereafter. MacDermid argued the patent was invalid based on, among other things, a public use of the invention at a trade show in September 2000, which would be a § 102(b) statutory bar if the patent's priority date was the nonprovisional filing date, making the critical date February 27, 2001. During the course of the preliminary injunction proceedings, including briefing and a hearing, counsel for DuPont did not dispute that the critical date should be calculated from the nonprovisional filing date.

Two days after supplemental briefing on the issue of whether this trade show was a "public use" of the invention was complete, counsel for DuPont brought the priority date issue to the attention of the district court, asserting that the proper critical date for purposes of § 102(b) was actually March 6, 2000, before the alleged trade show public use in September 2000. MacDermid sought to expunge this from the record, and to prevent DuPont from arguing the earlier priority date. MacDermid also advanced several other arguments that the patent was not entitled to the provisional priority date: (1) the provisional and nonprovisional, while having identical disclosures and claims, did not name the same inventors, (2) the statement in the ADS referring to the provisional application did not use the language from the MPEP, and (3) the filing receipt, published application, and issued patent did not include reference to the provisional, and DuPont did not alert the PTO to this deficiency until after the patent issued, which rendered the certificate of correction improper. The district court declined to expunge DuPont's assertions regarding priority from the record, but found that MacDermid's arguments regarding priority, combined with DuPont's earlier statements regarding the priority date created a substantial question of validity, and on that basis, denied the preliminary injunction. DuPont appealed.

The only issue before the Federal Circuit was whether the patent was entitled to the filing date of the provisional application. The court noted that entitledment to provisional priority is governed by 35 U.S.C. § 119(e)(1), which sets forth four requirements for priority:

(1) the provisional must comply with the requirements of section 112, first paragraph, and the non-provisional must be for the same invention; (2) the non-provisional must be filed within twelve months of the provisional; (3) there must be an overlap of inventorship; and (4) the non-provisional must include a specific reference to the provisional.

Here, it was undisputed the first two were met, so the issues were confined to the second two requirements, as well as DuPont's statements during the preliminary injunction proceedings that improperly identified the critical date.

The Federal Circuit had no trouble turning aside the argument that DuPont should be estopped from asserting the earlier priority. Because the underlying facts regarding entitlement to priority were undisputed, "DuPont's counsel's conflicting characterization of those facts is immaterial to the legal analysis and cannot serve to create a substantial question of validity." Because DuPont's statements could not form the basis of a substantial question of validity, the court turned to MacDermid's substantive arguments regarding priority.


In order for a nonprovisional application to claim priority to a provisional application, there must be at least one inventor in common between the two applications. Here, although the disclosure in each application was the same, the provisional named a single inventor, but the nonprovisional named five inventors. MacDermid argued that this showed one of the two inventorship listings was wrong, and that for the priority claim to be valid, DuPont needed to seek correction of inventorship in the provisional application. The court was unpersuaded. The MPEP states that such a correction is not necessary as long as there is at least one overlapping inventor, so this did not defeat the priority claim.

Specific reference to the provisional

MacDermid further argued that the statement in the nonprovisional application's ADS was insufficient to properly claim priority. Specifically, it argued that because the language from the MPEP was not used, the claim was ineffective. The relevant passage from the MPEP is reproduced below:

When the nonprovisional application is entitled to an earlier U.S. effective filing date of one or more provisional applications under 35 U.S.C. 119(e), a statement such as "This application claims the benefit of U.S. Provisional Application No. 60/—, filed —, and U.S. Provisional Application No. 60/ —, filed —." should appear as the first sentence(s) of the description or in an application data sheet.

Here, while the "magic" language was not used, the court held the language in the ADS qualified as a statement "such as" the one in the MPEP, and was thus valid.

Validity of certificate of correction

Finally, MacDermid asserted the certificate of correction was invalid because the mistake was DuPont's, not the USPTO's. Specifically, MacDermid argued that because the omission of the priority claim was present in the filing receipt and published application, DuPont should have brought it to the UPSTO's attention earlier, and thus the exclusion of the priority claim from the issued patent was DuPont's error. The court disagreed, stating that "a lack of diligence during prosecution, at least under the facts of this case, does not convert a PTO error into an applicant error for the purpose of seeking a post-issuance certificate of correction." While it would have been better had the error been discovered and corrected while the application was pending, the fact that it was not did not change the fact that it was a USPTO error. As a result, the certificate of correction was valid.

Accordingly, the court held the patent was entitled to the provisional priority date. The court therefore vacated the denial of the preliminary injunction and

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