Sisvel International S.A. v. Sierra Wireless, Inc., Appeal Nos. 2022-1493, -1547 (Fed. Cir. Oct. 6, 2023)

Our Case of the Week falls in a series of cases concerning patents that claim a means for performing a particular function using a general-purpose computer.  That line of cases has held that the patent must disclose an algorithm that would perform the function.  Without that, the claims are deemed indefinite.  In an inter partes review, this posed particular concerns, because the PTAB is not authorized to find a patent invalid as indefinite—an inter partes review can only render a patent invalid over prior art.  Where the claim is indefinite, it would theoretically not be possible to match the claim element up with prior art.

In the instant case, the patent concerned data transmission technology.  Specifically, the patents related to coding data to using data blocks, where redundant data is used, allowing a receiver to detect and correct errors in the transmitted data with greater accuracy.  One claim recited “means for detecting,” which the Board construed as a means-plus-function claim, thus requiring disclosure of an algorithm under this line of cases.  Sierra identified the patent’s disclosure of two well-known error detection codes as examples of algorithms, and further supplied expert testimony concerning those error detection algorithms.  The PTAB, however, found that the patent disclosed insufficient structure—i.e., no corresponding algorithm—and that the testimony could not remedy the insufficient structure disclosed in the specification itself.

The Federal Circuit found the PTAB’s approach to be error, and provided a lengthy, 11-page explanation for the benefit of the patent legal community.

As stated in the Court’s 2012 opinion in Noah Systems, Inc. v. Intuit Inc., 675 F.3d 1302 (Fed. Cir. 2012), there are two types of cases that entail means-plus-function claims performed by computers.  The first is a case in which no algorithm is disclosed, and the claim is indefinite as a result.  In such cases, expert testimony is irrelevant, because it cannot save the claim.  The second type of case involves disclosure of some arguable algorithm.  In such cases, an expert may be helpful to identify what the disclosure means to a person of ordinary skill in the art, and thereby to determine its sufficiency.

Here, the patent disclosed two error-detection protocols by name.  Sierra’s expert explained what those protocols meant to those in the art.  It was error for the Board to have declined to consider this testimony in determining whether the patent disclosed sufficient structure in the form of an algorithm.

The Court issued two other cautionary notes.  First, merely disclosing another specification does not suffice to incorporate that other specification by reference.  Rather, it only raises the question of whether the identification of the specification in itself speaks sufficiently to those of skill in the art to inform them of a known algorithm.  Second, if the Board finds that the specification lacks an adequately disclosed algorithm, it must follow the Court’s mandate from Intel Corp. v. Qualcomm Inc., 21 F. 4th 801 (Fed. Cir. 2021).  We discussed that case here.

In the Board’s ultimate findings with regard to obviousness, it had found claims 1-3 and 9 obvious over a single prior art reference referred to as Chen.  However, the board declined to find claims 4-8 and 10 obvious.  For those claims, the petition sought to combine Chen with various references relating to the Global System for Mobile Communications Technical Specification (GSM).

On appeal, Sisvel challenged the PTAB’s obviousness analysis concerning claims 1-3 and 9 over Chen.  The Federal Circuit readily found substantial evidence to support the PTAB’s determination, including citations to Chen itself, based on expert testimony.

In its cross-appeal, Sierra argued that the PTAB erred in finding insufficient evidence of a motivation to combine Chen with the GSM references.  Sierra proposed ten reasons for combining them.  The PTAB found those reasons insufficient “as an articulated reason with a rational underpinning to combine the respective teachings of the references.”  The Federal Circuit agreed that the proposed combinations and rationales “were expressed at such a non-specific, high level of generality, they never made clear to the Board what portions of the references were being combined and why a skilled artisan would identify those particular elements for a combination.”  Three of the reasons “were merely assertions that the references were analogous art,” which is an insufficient reason to combine.  The other reasons “were too conclusory, lacked clarity, or suffered from both problems.”  For example, the petition did not make clear which reference was the primary and which was the secondary reference, or why particular elements would be obvious to add.  Moreover, there was inconsistency in how they should have been combined.

The Court remanded for further consideration of the “means for detecting” claim term.

The case is available here.

By Nika Aldrich


Schwendimann v. Neenah, Inc., Appeal Nos. 2022-1333, -1334, -1427, -1432 (Fed. Cir. Oct. 6, 2023)

In this case, the Federal Circuit affirmed inter partes review decisions of the Patent Trial and Appeal Board finding challenged claims of multiple related patents to be obvious over the prior art.  Of note, the Court indicated in this case that which reference is the “primary” reference in an obviousness analysis—i.e., the reference to be modified by the teachings of other references—is typically “merely a matter of presentation with no legal significance.”  Here, the Court rejected appellant Schwendimann’s argument that the Board was required to articulate a specific rationale for selecting a particular reference as the “primary” reference in its obviousness analysis.

The challenged patents concerned use of multi-layer transfer sheets for transferring printed images onto fabrics; in particular, the use of white or luminescent sheets as a background to improve image quality when transferring dark images onto dark-colored fabrics.  The Board found the challenged claims obvious over a combination of prior art referred to as Kronzer and Oez, where Kronzer taught the kind of “peel-last” multi-layer transfer sheets utilized in the claimed invention, and Oez taught a “peel-first” transfer method utilizing a white sheet to improve image quality for dark-colored fabrics.  The Federal Circuit found the Board’s “motivation to combine” and “likelihood of success” determinations to be supported by substantial evidence.  The Court also found Schwendimann’s “primary reference” argument to have been insufficiently preserved for appeal, but nonetheless addressed it briefly, stating that it “has no basis in our case law,” suggesting that a patent challenger need not analyze extensively which prior art reference a skilled artisan would “start” with to arrive at the claimed invention, or why.

The opinion can be found here.

By Jason A. Wrubleski

This article summarizes aspects of the law and does not constitute legal advice. For legal advice for your situation, you should contact an attorney.

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