Masimo v. Sotera Wireless & Hon Hai: 9-Patent ViSi Mobile Monitoring Dispute Dismissed With Prejudice
Masimo Corp. sued Sotera Wireless and parent company Hon Hai Precision Industry over nine patents covering continuous patient monitoring technology, targeting the ViSi Mobile system and its component modules. After nearly five years of litigation in the Southern District of California, all parties filed a stipulated dismissal with prejudice — closing the case entirely across all defendants.
A five-year wearable patient monitoring patent war ends by stipulation
Masimo Corporation, the Irvine-based pulse oximetry and patient monitoring leader, filed suit on June 12, 2019 in the U.S. District Court for the Southern District of California against Sotera Wireless, Inc. and Hon Hai Precision Industry Co., Ltd. The complaint asserted nine patents — a combination of original grants and reissue patents — covering core technologies in continuous, wearable patient monitoring. The accused products comprised the entire ViSi Mobile ecosystem: the Monitoring System, Chest Module, Cuff Module, Monitor, Remote Viewer, Thumb Sensor, Wrist Cradle, and Wrist Strap.
The case closed on May 23, 2024, when the court granted a joint motion to dismiss pursuant to Rule 41(a)(1)(A)(ii) — a stipulated dismissal signed by all appearing parties. The court construed the stipulation as a joint motion consistent with local civil rules and dismissed the action in its entirety, as to all defendants, with prejudice. A dismissal with prejudice carries full res judicata effect: Masimo is permanently barred from reasserting these specific claims against Sotera Wireless and Hon Hai in federal court.
The 1,807-day duration — nearly five years — is notable even for complex multi-patent litigation and suggests the parties engaged in substantial pretrial activity before reaching resolution. The Basis of Termination field references ‘Injunction Granted,’ which is in tension with the stipulated dismissal record; the public docket does not clarify whether a prior injunction or confidential settlement drove the ultimate stipulation. The financial and licensing terms, if any, remain entirely private, consistent with a negotiated resolution rather than a litigated outcome.
Filing to Injunction Granted in 1807 days
1,807 days — nearly 5 years, well above the median district court patent case duration of ~2.5 years
Dismissed with prejudice: what the stipulated exit means for both parties
Rule 41(a)(1)(A)(ii): dismissal by signed stipulation
Under Federal Rule of Civil Procedure 41(a)(1)(A)(ii), all parties who have appeared may jointly stipulate to dismiss an action. The court’s order notes that dismissal is effective upon filing — no court order is technically required — but S.D. Cal. local rules required the stipulation to be filed as a joint motion. The court construed the parties’ filing accordingly and granted it. This is the cleanest procedural exit available: mutually agreed, court-endorsed, and immediately effective.
Stipulated exit — all defendantsWith prejudice means these claims cannot be refiled
A dismissal with prejudice is a final adjudication on the merits for res judicata purposes. Masimo cannot refile suit against Sotera Wireless or Hon Hai on these nine patents for the accused ViSi Mobile products. This is meaningfully different from a without-prejudice dismissal, which would preserve the right to refile. The public record confirms the with-prejudice designation explicitly in the court’s order, leaving no ambiguity on this point.
Res judicata appliesSotera and Hon Hai exit with permanent closure on asserted claims
For Sotera Wireless and Hon Hai, the with-prejudice dismissal provides litigation finality on all nine asserted patents as applied to the ViSi Mobile product line. Whether this reflects a confidential settlement, a licensing agreement, or a strategic decision by Masimo to withdraw is not disclosed in the public record. The involvement of Hon Hai — a major contract electronics manufacturer — alongside Sotera suggests the dispute had supply-chain dimensions beyond the end-product maker alone.
Full closure — all defendantsNine reissue and utility patents still active in Masimo’s enforcement arsenal
The dismissal resolves this specific dispute but does not affect the validity or enforceability of Masimo’s nine asserted patents. Masimo retains the right to enforce US9795300B2 and the eight co-asserted patents against other parties in the continuous wearable monitoring space. The reissue patents in the portfolio — USRE047244E, USRE047218E, USRE047249E, USRE047353E — suggest Masimo actively broadened claim scope post-grant, signalling an aggressive, forward-looking enforcement posture in this technology sector.
Patents remain enforceableFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Masimo, Corp. | Company | Patient monitoring technology company — holder of US9795300B2 and 8 further continuous monitoring patentsSearch in Eureka ↗ |
| Defendant | Sotera Wireless, Inc. | Company | Sotera Wireless (ViSi Mobile system maker) and Hon Hai Precision Industry Co., Ltd. (parent/manufacturer)Search in Eureka ↗ |
| Co-Defendant | Hon Hai Precision Industry Co., Ltd. | Company | Search in Eureka ↗ |
| Plaintiff counsel | Baraa Kahf | Attorney | Counsel for Masimo, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Brian Christopher Claassen | Attorney | Counsel for Masimo, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Irfan A. Lateef | Attorney | Counsel for Masimo, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Jonathan Bachand | Attorney | Counsel for Masimo, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Joseph R. Re | Attorney | Counsel for Masimo, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Mark D. Kachner | Attorney | Counsel for Masimo, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Perry D. Oldham | Attorney | Counsel for Masimo, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Stephen C. Jensen | Attorney | Counsel for Masimo, Corp.Search in Eureka ↗ |
| Plaintiff law firm | Knobbe Martens Olson & Bear, LLP | Law Firm | Representing Masimo, Corp.Search in Eureka ↗ |
| Defendant counsel | Daisy Manning | Attorney | Counsel for Sotera Wireless, Inc.Search in Eureka ↗ |
| Defendant counsel | Dustin L Taylor | Attorney | Counsel for Sotera Wireless, Inc.Search in Eureka ↗ |
| Defendant counsel | Jennifer E. Hoekel | Attorney | Counsel for Sotera Wireless, Inc.Search in Eureka ↗ |
| Defendant counsel | John Christopher Jaczko | Attorney | Counsel for Sotera Wireless, Inc.Search in Eureka ↗ |
| Defendant counsel | Nathan P. Sportel | Attorney | Counsel for Sotera Wireless, Inc.Search in Eureka ↗ |
| Defendant counsel | Rudolph A. Telscher , Jr. | Attorney | Counsel for Sotera Wireless, Inc.Search in Eureka ↗ |
| Defendant counsel | Steven M Strauss | Attorney | Counsel for Sotera Wireless, Inc.Search in Eureka ↗ |
| Defendant law firm | Cooley LLP (Library) | Law Firm | Representing Sotera Wireless, Inc.Search in Eureka ↗ |
| Defendant law firm | Husch Blackwell LLP | Law Firm | Representing Sotera Wireless, Inc.Search in Eureka ↗ |
| Defendant law firm | Procopio, Cory, Hargreaves & Savitch, LLP | Law Firm | Representing Sotera Wireless, Inc.Search in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | California Southern District CourtSearch in Eureka ↗ |
Official order — verbatim text
The court’s order reproduces the Rule 41(a)(1)(A)(ii) framework in full, underscoring the procedural basis for dismissal and confirming that no substantive merits ruling was issued. The phrase ‘dismissed in its entirety, as to all defendants, with prejudice’ is unambiguous: all claims, all patents, and all defendants are resolved in one order. The ‘good cause shown’ recital is standard and does not reflect any merits finding. The absence of cost-and-fee language is consistent with a negotiated resolution where each side bears its own fees, though this is not expressly confirmed in the public record.
US9795300B2 and 8 co-asserted patents — continuous wearable patient monitoring
The nine asserted patents — spanning original utility grants (US9795300B2, US10213108B2, US10255994B2, US9788735B2, US9872623B2) and four reissue patents (USRE047244E, USRE047218E, USRE047249E, USRE047353E) — collectively cover the core technology stack underlying continuous, wearable patient monitoring: sensor design, signal acquisition, wireless data transmission, physiological parameter calculation, and remote display. The reissue patents indicate that Masimo pursued USPTO reexamination to refine and potentially broaden claim scope after original grant, a common strategy in anticipation of enforcement.
Masimo is a dominant force in pulse oximetry and continuous monitoring IP, with one of the largest and most litigated portfolios in the clinical monitoring space. The breadth of this nine-patent assertion — targeting every hardware component of the ViSi Mobile system from the thumb sensor to the wrist cradle — signals a comprehensive claim mapping exercise against a direct competitor. For any company developing ambulatory monitoring, hospital-grade wearables, or wireless biosensor platforms, these patents represent a significant freedom-to-operate risk that predates and survives this particular litigation.
Should you run an FTO against US9795300B2 and the Masimo monitoring portfolio?
Any R&D team developing wearable continuous patient monitoring hardware — including SpO2 sensors, ECG patches, blood pressure cuffs, wrist-worn vital-signs monitors, or wireless patient monitoring platforms — faces material infringement exposure from Masimo’s portfolio. The nine patents asserted here cover both the physical sensor modules and the system-level architecture. With four reissue patents in the set, claim scope may extend beyond what the original filing dates suggest. An FTO analysis should cover granted claims, reissue amendments, and any pending continuations.
PatSnap Eureka’s FTO Search Agent allows product and IP teams to map claim elements from US9795300B2 and each co-asserted patent against your specific product architecture — flagging overlap, identifying design-around opportunities, and surfacing prior art that may support future IPR petitions. For medtech companies entering the clinical wearables market, a Eureka FTO run across this Masimo cluster is a defensible first step before committing to product design choices that could trigger enforcement.
Run a freedom-to-operate analysis on US9795300B2 to assess your product’s exposure
Run FTO in Eureka →Similar wearable patient monitoring patent cases in U.S. district courts
Cases involving wearable biosensor and continuous patient monitoring patents litigated in California federal district courts, including other Masimo enforcement actions.
What this case signals for the wearable patient monitoring IP landscape
Masimo’s nine-patent assertion against ViSi Mobile illustrates a high-stakes enforcement model in continuous monitoring — and raises portfolio risk questions for the broader sector.
Reissue patents signal deliberate claim broadening — watch the scope
Four of Masimo’s nine asserted patents are reissues (RE047244, RE047218, RE047249, RE047353). Reissue proceedings allow patentees to broaden or correct claims post-grant. Their presence in the assertion set suggests Masimo strategically widened its claim coverage before filing suit — a pattern that increases infringement risk for competitors working in wearable biosensor and continuous vital-signs monitoring.
Supply-chain defendants are increasingly common in medtech patent suits
Naming Hon Hai Precision alongside Sotera Wireless reflects a strategy of targeting both the product designer and the manufacturer. For medtech companies relying on contract electronics manufacturers, this case is a reminder that IP indemnification clauses in supply agreements carry real litigation exposure — particularly where the OEM holds a large portfolio and the supply chain partner has deep pockets.
Masimo v Sotera — key questions answered
The case was dismissed with prejudice on May 23, 2024, pursuant to a joint stipulation under Rule 41(a)(1)(A)(ii). The dismissal covered all nine asserted patents and all defendants — Sotera Wireless and Hon Hai Precision Industry. Masimo cannot refile these specific claims against these defendants. The case ran for 1,807 days before resolution.
Masimo asserted nine patents: US9795300B2, USRE047244E, US10213108B2, US10255994B2, US9788735B2, USRE047218E, USRE047249E, US9872623B2, and USRE047353E. The portfolio combines original utility grants with four reissue patents, collectively covering wearable continuous patient monitoring hardware and system architecture.
The accused products comprised the full ViSi Mobile Monitoring System and its components: the Chest Module, Cuff Module, Monitor, Remote Viewer, Thumb Sensor, Wrist Cradle, and Wrist Strap. The assertion targeted the entire hardware ecosystem of Sotera’s wearable continuous monitoring platform.
A dismissal with prejudice means Masimo is permanently barred from asserting the nine patents in this case against Sotera Wireless and Hon Hai for the accused ViSi Mobile products under res judicata doctrine. However, the patents remain valid and fully enforceable against third parties — Masimo retains the right to sue other companies in the wearable monitoring space under the same patents.
Four of the nine asserted patents are reissues (USRE047244E, USRE047218E, USRE047249E, USRE047353E). Reissue proceedings allow a patentee to correct or broaden claim scope after original grant, subject to USPTO review. Their inclusion in the assertion set suggests Masimo strategically refined its claim coverage — potentially widening the infringement footprint — before filing suit, which is consistent with Masimo’s historically aggressive IP enforcement posture.
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