The Patent Trial and Appeal Board (PTAB) has invalidated all claims across two patents held by Proxense LLC, an Oregon-based startup, following challenges by Microsoft Corporation. This decision marks a significant development in the ongoing legal disputes between the two companies.
Proxense initiated litigation against Microsoft in May 2023, alleging infringement of six patents related to biometric authentication and personal digital key technology. The case, filed in the U.S. District Court for the Western District of Texas, is titled Proxense, LLC v. Microsoft Corporation, No. 6:23-cv-00319. In response, Microsoft filed petitions for inter partes review (IPR) with the PTAB, challenging the validity of Proxense’s patents.
One of the patents in question, U.S. Patent No. 8,646,042 B1, titled “Hybrid Device Having a Personal Digital Key and Receiver-Decoder Circuit and Methods of Use,” was subjected to IPR2024-00573. The PTAB instituted the review on August 13, 2024, and subsequently found all challenged claims unpatentable. The board’s decision emphasized that Microsoft demonstrated a reasonable likelihood of prevailing in its challenge, leading to the invalidation of the patent’s claims. ([docketalarm.com](https://www.docketalarm.com/cases/PTAB/IPR2024-00573/Microsoft_Corporation_v._Proxense_LLC/08-13-2024-Board/Institution_Decision__Grant-11-Institution_Decision__Grant/?utm_source=openai))
Similarly, in IPR2024-00407, the PTAB reviewed another Proxense patent and issued a final written decision on July 17, 2025, declaring all challenged claims unpatentable. The administrative patent judges involved in these decisions included Norman H. Beamer, David C. McKone, and Thu A. Dang. ([ai-lab.exparte.com](https://ai-lab.exparte.com/case/ptab/IPR2024-00407/microsoft-corporation-v-proxense-llc?utm_source=openai))
These PTAB rulings represent a strategic victory for Microsoft, effectively nullifying key patents that were central to Proxense’s infringement claims. The decisions may influence the trajectory of the ongoing district court case, potentially leading to its dismissal or a favorable settlement for Microsoft.
Proxense, founded by inventor John J. Giobbi, has been active in asserting its patent portfolio against major technology companies, including Google, Apple, Intel, and Samsung. The invalidation of these patents by the PTAB could impact Proxense’s broader litigation strategy and its ability to enforce its intellectual property rights. ([mondaq.com](https://www.mondaq.com/unitedstates/patent/1495144/proxense-targets-lg-pay-digital-keys-and-wi-fi-connectivity?utm_source=openai))
As of July 21, 2025, Microsoft’s stock (MSFT) is trading at $510.06, reflecting a slight increase from the previous close. The company’s market capitalization stands at approximately $2.79 trillion, underscoring its robust position in the technology sector.
The PTAB’s decisions highlight the critical role of inter partes review in resolving patent disputes, offering a mechanism for companies to challenge the validity of patents outside of traditional courtroom litigation. This case underscores the importance for patent holders to ensure the robustness of their claims, particularly when facing challenges from well-resourced defendants like Microsoft.