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When may courts correct language in a patent claim?
It’s rare for courts to correct errors in patent claims — but it does happen. Read on to learn about the kind of circumstances that might compel a court to act.
Mistakes happen
Canatex Completion Solutions Inc. owns a patent for a two-part device used in oil and gas wells. Wellmatics LLC challenged the patent, arguing that certain patent claims were indefinite due to the lack of an antecedent basis for the phrase “the connection profile of the second part.” Canatex countered that a “relevant artisan” in the applicable field would clearly understand that the intended meaning was “the connection profile of the first part.”
It asked the trial court to interpret the phrase to reflect a correction of “second” to “first.” The court rejected that request and found the claims invalid for indefiniteness. Canatex appealed.
Court correction
The U.S. Court of Appeals for the Federal Circuit has repeatedly held that judicial correction of errors in patents is proper only in narrow circumstances. As such, it noted, the standards for judicial correction of a claim term are “very demanding.” Specifically:
- The error must be obvious from the face of the patent,
- The correction must not be subject to reasonable debate based on the claim language, specification or prosecution history, and
- The error must be a minor clerical or typographical error.
Applying those requirements, the appeals court held that Canatex was entitled to judicial correction.
Specifically, the court found that a relevant artisan would immediately see that, as written, the claim language had an error. The phrase at issue (“the connection profile of the second part”) plainly requires an antecedent — but no “connection profile of the second part” had previously been mentioned in the claim. Moreover, the error was evident on the face of the specification, where nothing in the figures or their descriptions showed a “connection profile” in the second part of the device. And the prosecution history didn’t suggest any other construction of the disputed language.
The appellate court concluded, too, that the proper correction wasn’t subject to reasonable debate. The only reasonable correction, it said, was to change “second” to “first.” Both the claim language as a whole and the specification showed this correction was what “the very character of the invention requires.”
Finally, the Federal Circuit found that the correction from “second” to “first” was simple as a textual matter. It followed that the error was properly characterized as a minor clerical or typographical error.
Don’t count on it
As the Federal Circuit’s ruling emphasizes, it’s no small task to obtain a judicial correction. Rather than hoping to satisfy the exacting standards, patent applicants should take care to ensure their claim language is unambiguous and error free.
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