PTO Rule on Continuation Filing Jeopardizes 12,000 Patents

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By Tony Dutra

May 6 — A technical nuance in the Patent and Trademark Office's rules for filing patent continuations may put at least 12,000 issued patents in jeopardy.

A three-judge panel of the U.S. Court of Appeals for the Federal Circuit heard oral arguments May 6 from patent owner Immersion Corp. and alleged infringer HTC Corp. Unless the panel overturns a ruling last year by the U.S. District Court for the District of Delaware, the PTO has been improperly advising applicants for at least 55 years.

The PTO has allowed applicants to file a continuation—a new set of claims for a previously applied-for invention—on the same day that a parent patent is issued.

But the district court said that Immersion's continuation filing could not claim priority to its parent due to a same-day filing. It said that, per Section 120 of the Patent Act, the continuation should have been filed one day earlier.

Two of the appeals court judges seemed inclined to defer to the PTO's interpretation of 35 U.S.C. §120, but the outcome of the case is by no means certain.

Same Date or Date Before?

Applicants want claims in the continuation to be given the same application date as the parent. Without that, the parent may actually serve as prior art—along with other information disclosed after the parent's application date—that can nullify the continuation claims' patentability.

The arguably ambiguous Section 120 treats any continuation “as though filed on the date of the prior application, if filed before the patenting or abandonment of or termination of proceedings on the first application.” The parties and judges debated whether “filing” and “patenting” are time-stamped events or legal constructs.

If the latter, as Immersion's counsel Joseph R. Palmore of Morrison & Foerster LLP, Washington, argued, the PTO should be free to treat “before” as something to be defined procedurally. And if the PTO's procedural definition—in the Manual of Patent Examining Procedure §211.01(b)(I)—allows same-day filing, courts should give deference to that interpretation.

Dan L. Bagatell of Perkins Coie LLP, Phoenix, represented HTC, which treats the events as dates. And there is little doubt that the date on which a patent issues is the date on which it is enforceable—i.e., as of one second after midnight on that date. With that understanding, a same-day continuation filing is too late.

Chief Judge Sharon Prost attacked Immersion's view, effectively chastising the PTO for—when it had the choice to pick a date—not opting to honor “before” and simply say that applicants should make sure they file their continuations the day before the patent is to issue.

But Benjamin M. Shultz of the Department of Justice defended the PTO's choice, based on 150 years of precedent. In 1863, the U.S. Supreme Court held that a continuation could be treated as if filed on the date the parent was filed if the applicant was withdrawing the original claims at the same time. Godfrey v. Eames, 68 U.S. (1 Wall.) 317 (1863).

That argument did not appear to convince Prost or her panel colleagues, Judges Richard Linn and Richard G. Taranto. The simultaneous withdrawal and continuation filing means only one application is active. That scenario does not present a question of co-pending applications, as Immersion needs to claim.

Nevertheless, the PTO has had this same-day filing rule at least since 1961, as part of its interpretation of the Patent Act of 1952. Palmore contended that Congress “has repeatedly amended Section 120” since then, and has left the PTO's interpretation alone.

Linn and Taranto didn't necessarily tip their hands as to how they would vote. But Linn admitted to “some ambiguity here,” and Taranto said that Section 120 was an example of “squishiness” that the PTO could be charged with having to resolve.

Significant Impact on Existing Patents

The PTO estimated that more than 13,500 patents issued since 2000 would be susceptible to attack if the Delaware holding is upheld, according to the U.S. government's brief filed before oral arguments. The Intellectual Property Owners Association filed an amicus brief citing Ocean Tomo LLP's estimate of 12,300 patents at risk.

If the Federal Circuit rules that the statute clearly requires continuations to be filed a day before the parent patent issues, it is unclear if the PTO could issue a regulation with a retroactive fix for those patents.

Bagatell also countered that the figures represented just 1 percent of patents in force. Further, he said, “only a small number are maintained and enforced,” and others that are susceptible could still survive depending on what new prior art could apply if the continuation loses its parent's priority date.

The number of patents at risk is “a trickle,” he said, “a tiny number of patents.”

The IPO brief identified an additional 30,000 patents at risk because of the second part of Section 120—“or termination of proceedings on the first application.” But neither the parties nor the judges appeared to have any doubt that those patents would not be affected by the Immersion outcome, since the 1863 Godfrey decision clearly said otherwise.

To contact the reporter on this story: Tony Dutra in Washington at

To contact the editor responsible for this story: Mike Wilczek in Washington at

For More Information

Argument at; cite appeal number 2015-1574.