Background
ImmerVision Inc. holds patents covering wide-angle panoramic lens technology — specifically, “panomorph” lenses used in cameras and imaging systems. LG Electronics filed inter partes review (IPR) petitions challenging ImmerVision’s patents as unpatentable over prior art references. One of the prior art references LG relied on contained a numerical value that, if taken at face value, would appear to support LG’s invalidity argument.
ImmerVision argued that the numerical value in the prior art reference was an obvious transcription error — a typographical mistake that a person of ordinary skill in the art would immediately recognize as wrong, and that the actual disclosure of the reference, properly understood, did not support LG’s obviousness theory. The PTAB agreed with ImmerVision, finding that the erroneous value should be disregarded, and that the reference did not establish unpatentability. LG appealed.
The Court’s Holding
The Federal Circuit affirmed, holding that when a prior art reference contains an obvious typographical or transcription error that a skilled artisan would readily recognize as a mistake, that erroneous value does not count as a disclosure for purposes of determining patentability. Prior art “discloses” what a person of ordinary skill in the art would understand it to disclose — and a skilled artisan would not understand an obvious misstatement to be an actual teaching of the reference.
The court found that the error in the prior art reference was indeed apparent to a skilled reader: the value in question was inconsistent with the rest of the reference’s technical content in a way that would signal to any expert that a mistake had been made. Under these circumstances, giving the erroneous value its literal meaning would misrepresent what the reference actually taught, and basing an invalidity finding on such a value would be legally incorrect. The court upheld the PTAB’s decision to disregard the transcription error and affirmed the finding of patentability.
Key Takeaways
- Prior art is interpreted through the eyes of a person of ordinary skill in the art — and that skilled artisan would recognize an obvious typographical or transcription error and understand that it does not represent an accurate disclosure.
- An invalidity argument that relies on an erroneous value in a prior art reference, when the error would be apparent to a skilled reader, will fail because the reference does not actually teach what the error appears to say.
- Patent owners challenging IPR proceedings can argue against reliance on prior art that contains apparent misstatements, supporting that argument with technical evidence showing why a skilled artisan would recognize the error.
- Petitioners building invalidity arguments from prior art references should carefully evaluate whether any critical numerical values, parameters, or claim elements in those references are internally consistent with the rest of the reference’s technical content.
Why It Matters
Prior art interpretation is central to both patent prosecution and patent litigation, and this case clarifies an important nuance: prior art is not read as a perfectly literal document. Courts and the PTAB interpret prior art the way a skilled artisan would — with technical understanding, contextual knowledge, and the ability to identify mistakes that no competent expert would take at face value.
For patent owners defending against IPR challenges, LG v. ImmerVision is a useful reminder that prior art references are not infallible. When a petitioner’s invalidity theory depends on a specific value or statement in a reference that appears to conflict with the rest of the technical content, that inconsistency is worth highlighting. And for IPR petitioners, the case is a caution against over-relying on specific numerical disclosures in references without first verifying their technical plausibility across the full content of the reference.