Patent Lodge

Many readers may recall the 2004 case, Chef America, Inc. v. Lanb-Weston, Inc., where the Federal Circuit upheld a district court’s refusal to correct claim language that the patentee argued was an obvious error. That case involved a process for making dough products where the claim called for “heating the dough to a temperature in the range of about 400 °F to 850 °F” (emphasis added). The patentee argued that heating the dough itself to that high temperature would burn it to a crisp. Rather, what the phrase meant was that the oven temperature should be in the claimed range, i.e., the term “to” should be interpreted as “at.” The infringer heated their oven to the specified temperature range but did not heat the dough itself to that temperature.

The Federal Circuit upheld the district court’s refusal to make the correction holding that the prosecution history suggested a different interpretation of the claims. They noted that the claims originally filed used both the phrase “heating to” and “heating at” in different claims, and during prosecution, the applicant amended several claims by changing “at” to “to,” so the history suggests that applicants were distinguishing between “heating to” and “heating at” a specified temperature. Additionally, the specification suggests the applicant intended a distinction.

Fast forward to the case, Canatex Completion Solutions, Inc. v. Wellmatics, LLC, decided this past November. The Federal Circuit reversed a finding of indefiniteness by the trial court, holding that the courts have authority to correct obvious claim errors through claim construction where the error is evident and only one reasonable construction exists.

In Canatex, the claims involved a releasable connection device used in oil and gas wells. The device included two parts, a “first part” and a “second part.”

All of the independent claims called for language stating that a locking piston moves “to release the connection profile of the second part (emphasis added).”

There was no antecedent basis for “the connection profile of the second part.” Instead, the prior portion of the claim identified “a connection profile of a first part” (emphasis added).

The defendant challenged the claims as indefinite for a lack of antecedent basis. The plaintiff argued that the term “second” was an obvious error that should be construed as “first.” They pointed to the claim language and specification showing that only the first part had a connection profile.

The district court rejected the plaintiff’s arguments and found the claim invalid as indefinite. The case was appealed and while the appeal was pending, the patentee sought correction from the USPTO to change “second” to “first.” The USPTO rejected their petition finding that the requested correction was more than a clerical or typographical mistake.

The Federal Circuit reversed the district court’s finding stating that courts have the authority to correct obvious clerical errors in patent claims through claim construction relying on a 1926 United States Supreme Court decision, I.T.S. Rubber Co. v. Essex Rubber Co. In that case the Court said it was clear that the correction was the meaning intended by the patentee and understood by the examiner. The Federal Circuit found that it was a clear claim construction decision by the Supreme Court. The Federal Circuit articulated a three-part test for when judicial correction is permissible:

1. Evident Error: The error must be “evident from the face of the patent” from the point of view of a skilled artisan.
2. No Reasonable Debate: The correction cannot be subject to a reasonable debate based upon a review of the patent document and prosecution history.
3. Minor: The correction is limited to “obvious minor typographical and clerical errors.”

The Federal Circuit applied the third element but was careful not to actually hold that it was a necessary element.

Applying the three-part test, the Federal Circuit found the error correctable. Regarding the first element, the court said that looking at the claim language itself, a skilled artisan would “immediately see” that the phrase “the connection profile of the second part” lacks antecedent basis because the claims never previously mention any connection profile of the second part. More fundamentally, the reference to releasing “the connection profile of the second part” makes no functional sense. A skilled reader would recognize that what gets released through this radial expansion must be the component that was embraced (the connection profile of the first part).

The opinion mentioned the USPTO’s denial of the certificate of correction but found no preclusion of judicial correction.

In Canatex, the Federal Circuit distinguished Chef America on the basis of prosecution history, finding no relevant prosecution history to deny the proposed Canatex change. Namely, there were no amendments switching between “first part” and “second part,” no examiner statements suggesting applicant intended to distinguish between them, and no other indicia that the erroneous language might have been intentional.

Perhaps the much-criticized hyper-technical claim language reach of Chef America has now been limited by Canatex.