Rarely Used Legal Doctrine May Determine Google’s Fate in Patent Dispute

A monster jury award last year against Google on a patent infringement claim caused a lot of heads to turn in the intellectual property world. But what happened next made those same heads, including my own, spin.

A federal judge in California threw out the $32.5 million verdict, ruling that the patents asserted by wireless-audio company Sonos were unenforceable due to the rarely invoked legal doctrine of prosecution laches. How rare is it? In more than two decades of practicing IP law, I have never once invoked prosecution laches as a material defense. In fact, it was not until 2021 that the United States District Court for the Federal Circuit confirmed that prosecution laches defense was even available to the United States Patent and Trademark Office (Hyatt v. Hirshfeld, 998 F.3d 1347 (Fed. Cir. 2021)).

The surprise ruling and resulting appeal by Sonos now moves the matter to the U.S. Court of Appeals for the Federal Circuit, which has exclusive jurisdiction on all federal patent appeals. There, the sharply worded opinion by U.S. District Judge William Alsup will be met with a sharply contrasting view by Sonos, if the company’s briefing is any indication.

But first, a little background. For years, Sonos has battled with Google over multi-room smart speaker technology and who invented what first. Sonos has claimed its provisional application for multi-room technology, which it filed in September 2006, should have priority over a later Google invention. A San Francisco jury agreed with that viewpoint in May 2023 and ordered Google to pay the monster damages.

Then, last fall, Judge Alsup threw out the verdict based on Google’s prosecution laches defense. That is, Sonos delayed too long during the patent application process for the multi-room technology, including attempts to attach new patents to older ones for strategic benefit. This fits the doctrine of prosecution laches, which holds that a patent applicant can forfeit the right to enforce a patent based on “an egregious misuse of the statutory patent system.”

In Judge Alsup’s view, Sonos “was guilty of unreasonable and inexcusable delay in its prosecution of the patents in suit.” The judge recapped by noting that Sonos filed the provisional application from which the patents claim priority in September 2006, but it did not file applications for the patents in the lawsuit until April 2019. Moreover, Judge Alsup said that those claims were amended to include “standalone mode” limitations in August 2019 before the applications issued as patents in November 2019 and November 2020.

“That was over thirteen years after Sonos had filed the provisional application,” wrote Judge Alsup. “That was also well after Google had disclosed the claimed invention to Sonos and, on its own, brought the claimed invention to the market.”

He further added: “This was not a case of an inventor leading the industry to something new. This was a case of the industry leading with something new and, only then, an inventor coming out of the woodwork to say that he had come up with the idea first — wringing fresh claims to read on a competitor’s products from an ancient application.”

The judge’s opinion also explicitly defends and affirms the validity of prosecution laches. He stated: “Much ink has been spilled by Sonos in seeking to demonstrate that the affirmative defense of prosecution laches is dead. It is not.”

The opinion’s conclusion is equally stinging to Sonos. “It is wrong that our patent system was used in this way,” Alsup wrote. “With its constitutional underpinnings, this system is intended to promote and protect innovation. Here, by contrast, it was used to punish an innovator and to enrich a pretender by delay and sleight of hand. It has taken a full trial to learn this sad fact, but, at long last, a measure of justice is done. In sum, under the doctrine of prosecution laches, the patents in suit are UNENFORCEABLE.”

As I mentioned above, Sonos has appealed and, in its most recent briefing, indicated it will not let the decision stand without a fight.

Lawyers for Sonos wrote: “The district court has strong views about ‘the way the patent system should work.’ But those views conflict with the Patent Act, the Federal Rules of Civil Procedure, and this Court’s precedent. Undeterred, the district court rewrote patent law and reconstituted the judicial role to erase a $32.5 million jury verdict and throw out other patent claims that should have been tried.”

The brief goes on to say that prosecution laches does not apply to the Sonos patents and that the Federal Circuit “should not break new ground by endorsing the doctrine’s application in this case.” Sonos also argues that the district court “abused its discretion.”

Needless to say, IP lawyers and experts are watching the appeal closely. Missouri School of Law Professor Dennis Crouch, who recently described the district court opinion as “one of the more shocking patent decisions of 2023,” said the outcome “could have significant implications for how patents are prosecuted and enforced.”

He notes that “Sonos’ prosecution approach in the case is a widespread practice in the field and so the case raises significant questions about both patent enforcement strategies and equitable loss of rights based upon ‘late claiming’ where claims are amended in response to market conditions.”

The Federal Circuit’s opinion in this case could have considerable implications, with many in the IP world paying attention and even weighing in. At least five IP, technology and innovation based organizations have filed or moved to file amicus curiae briefs (so-called “friends of the court” briefs) in this appeal. The organizations include the George Washington University Law School Intellectual Property & Technology Law Clinic, the American Intellectual Property Law Association (AIPLA), and the Public Interest Patent Law Institute.

Google filed its response brief last month and Sonos is expected to file its reply brief on July 22, which should close out the briefing schedule. I will continue to monitor this interesting case and provide additional commentary as the Google-Sonos battle continues.