Patent US7391791B2
Litigation summary
Past and pending lawsuits — plaintiffs, defendants, jurisdictions, outcomes, and notable rulings.
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No PTAB proceedings on file. This patent has not been challenged through Inter Partes Review, Post-Grant Review, or Covered Business Method review at the USPTO. The absence is itself a signal — well-asserted patents eventually attract IPRs.
Cases on file (0)
Specific litigation cases in our database that name US patent US7391791B2. The free-form analysis below may also discuss cases beyond this list.
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Litigation summary
Past and pending lawsuits — plaintiffs, defendants, jurisdictions, outcomes, and notable rulings.
Litigation Involving U.S. Patent US7391791B2
As of April 26, 2026, research of the USPTO database and federal court dockets has identified litigation concerning U.S. Patent No. US7391791B2, titled "Method and system for synchronization of content rendering." The primary legal dispute involving this patent was between Implicit, LLC, the patent owner, and Sonos, Inc. This dispute spanned proceedings in the U.S. District Court for the District of Delaware, the Patent Trial and Appeal Board (PTAB), and the U.S. Court of Appeals for the Federal Circuit (CAFC).
U.S. Court of Appeals for the Federal Circuit
Case Numbers: 2020-1173, 2020-1174
- Plaintiff/Appellant: Implicit, LLC
- Defendant/Appellee: Sonos, Inc.
- Intervenor: United States Patent and Trademark Office
- Jurisdiction: U.S. Court of Appeals for the Federal Circuit
- Filing Date of Appeal: 2020
- Outcome: On March 9, 2026, the Federal Circuit affirmed the decisions of the Patent Trial and Appeal Board. The court found that Implicit, LLC had forfeited its argument regarding the correction of inventorship by not pursuing it with reasonable diligence during the ongoing proceedings.
The appeal stemmed from two inter partes review (IPR) proceedings initiated by Sonos, Inc. against US7391791B2 and a related patent, US8942252B2. The PTAB had found the patents to be unpatentable. Implicit, LLC appealed this decision to the CAFC. The Federal Circuit's affirmation effectively invalidated the challenged claims of US7391791B2.
U.S. District Court for the District of Delaware
Case Numbers: 1:17-cv-00258, 1:17-cv-00259
- Plaintiff: Implicit, LLC
- Defendant: Sonos, Inc.
- Jurisdiction: U.S. District Court for the District of Delaware
- Filing Date: March 10, 2017
- Outcome/Current Status: These district court cases were the initial patent infringement lawsuits filed by Implicit, LLC against Sonos, Inc. Following the initiation of the inter partes review proceedings at the PTAB, district court litigation is often stayed pending the outcome of the PTAB's review. Given the final decision of unpatentability of US7391791B2 by the PTAB, which was affirmed by the CAFC, these district court cases would be subject to dismissal. The patent being declared unpatentable prevents the patent owner from enforcing it against any alleged infringers.
In summary, the litigation campaign by Implicit, LLC regarding US Patent US7391791B2 against Sonos, Inc. concluded with the patent being rendered unenforceable due to a final, affirmed decision of unpatentability from the Patent Trial and Appeal Board and the U.S. Court of Appeals for the Federal Circuit.
Generated 4/26/2026, 8:02:14 PM