Federal Circuit Narrows Prosecution Laches in Google v. Sonos

Overview

In Google LLC v. Sonos, Inc., the U.S. Court of Appeals for the Federal Circuit reversed in part a district court ruling that had held Sonos’s “Zone Scene” patents unenforceable due to prosecution laches. The Federal Circuit found that Google failed to carry its burden to show prejudice from Sonos’s delay, and thus the district court’s unenforceability finding was an abuse of discretion. While the decision allows patent holders and applicants that are building portfolios through the use of strategic continuing applications to breathe a sigh of relief in many cases, it leaves open the possibility where a defense of unenforceability due to prosecution laches may still succeed.

Background

Sonos’s “Zone Scene” patents at issue (U.S. Patents 10,469,966 and 10,848,885) are directed to “overlapping zone scenes” in networked media playback systems—i.e., configurations in which a given speaker (a “zone player”) can simultaneously belong to multiple groups (“zone scenes”). Google argued in the district court that (1) Sonos had unreasonably delayed prosecuting the overlapping-zone-scene claims, and (2) Google (and the market) had been investing in products implementing these features before Sonos claimed them, thus prejudicing Google. The district court agreed, rendering the Zone Scene patents unenforceable under the doctrine of prosecution laches, among other fact-specific issues in the case.[1]

What the Federal Circuit Held

The Federal Circuit reversed the district court’s unenforceability ruling for the Zone Scene patents based on prosecution laches. The Court largely limited its analysis to the prejudice prong of the laches defense, concluding that Google failed to show any prejudice attributable to the delay for two independent reasons.

First, the Federal Circuit found that Google did not present sufficient evidence to support its claim that it began investing in the accused functionality by 2015, or that it was unaware of Sonos’s invention at that time.

Second, and perhaps more importantly, the Federal Circuit found that Sonos’s earliest non-provisional application was published in 2013, well before Google’s claimed investments. Because the specification (as published) reasonably disclosed the later-claimed overlapping zone scenes, Google could not be prejudiced by incorporating into its products a feature already disclosed in a public document before it made its investment. In short, once the invention is publicly disclosed, a delay in claiming features adequately supported in the disclosure does not necessarily translate to prejudice.

What the Decision Did Not Decide

The Federal Circuit did not definitively rule that delays in claiming particular subject matter, like the 13-year delay here, would always avoid a defense relying on prosecution laches. The opinion leaves room for circumstances in which delay plus prejudice might suffice (of course, given sufficient evidence). For companies managing large continuing application portfolios, or tailoring portfolios as markets evolve, the Court also favorably did not proclaim that simply following standard continuation practice (even over long periods) is enough to trigger laches without a showing of prejudice.

Strategic Takeaways

Despite concerns by the patent bar at the time the district court decision was rendered, the Federal Circuit in Google v. Sonos pushed back on a potentially vast expansion of prosecution laches, particularly for so-called “late” or “serial” continuation filings. The decision provides reassurance for many patentees and applicants using standard continuation practice, including those that have early effective filing dates used for mining in the future. However, some risk remains, for example, for late-added claims with tenuous specification support, applications under a non-publication request that are pending for a long period of time, or where the patentee’s actions arguably obscure knowledge of the claimed invention. So robust specifications at the time of filing, considering parallel continuations where budget allows, and exercising compact prosecution principles remain valuable tools in a company’s overall IP strategy.

For companies engaged in competitive product development that are later accused of infringement, the decision underscores the importance of contemporaneous documentation. For example, evidence showing when the potentially infringing product development or investments began can be used to bolster the prejudice element, with a critical eye toward what was publicly disclosed at that time. Critically, evidence must be marshalled to show specific, causal prejudice: investments, changes in reliance, or inability to avoid infringing because of lack of notice are all available categories of evidence that may be useful to satisfy the prejudice element. Without that, prejudice to support a laches defense may be hard to prove.

Finally, keep in mind that while the Google v. Sonos decision is important, as a non-precedential decision, its value is persuasive rather than binding.

[1] For discussion of other issues in the case see:

Sua Sponte Finding of Invalidity in Sonos v. Google Creates Confusion at Federal Circuit

Federal Circuit Reverses Prosecution Laches in Google v. Sonos