Masimo v. Apple (Fed. Cir. 22-1894): Pulse Oximeter Patent Affirmed Unpatentable
Masimo Corporation appealed a patentability ruling at the Court of Appeals for the Federal Circuit against Apple Inc., asserting US6771994B2 covering a pulse oximeter probe-off detection system. After 576 days, the Federal Circuit affirmed the lower tribunal’s finding of unpatentability — a decisive win for Apple in the wearable health-sensing IP dispute.
Federal Circuit seals Apple’s invalidity win in wearable oximetry IP battle
Masimo Corporation, a medical-device company and holder of US6771994B2 relating to a pulse oximeter probe-off detection system, filed this appeal before the Court of Appeals for the Federal Circuit on 13 June 2022. The case, docketed as 22-1894, named Apple Inc. as respondent and concerned the patentability of core signal-processing technology used in non-invasive blood-oxygen monitoring — a capability central to Apple Watch’s health features.
The Federal Circuit issued its order on 10 January 2024, affirming the underlying tribunal’s determination of unpatentability. The single-word disposition — ‘AFFIRMED’ — confirms that the claims of US6771994B2 were found unpatentable and that Masimo’s appeal failed to overturn that finding. An affirmance at this level is final absent a successful petition for certiorari to the Supreme Court, meaning the invalidated claims are effectively extinguished.
The 576-day appellate timeline is consistent with the Federal Circuit’s typical scheduling for inter partes review or post-grant appeals involving complex patentability arguments. The terse ‘affirmed’ disposition suggests the court found no reversible error in the lower tribunal’s analysis, though the absence of a published opinion in the public record limits visibility into the specific legal reasoning. The outcome leaves open questions about Masimo’s broader patent portfolio strategy against Apple, given concurrent litigation in other forums.
Filing to settlement in 576 days
576 days from filing to Federal Circuit decision
Federal Circuit affirms unpatentability of Masimo’s US6771994B2
What ‘affirmed unpatentable’ means for US6771994B2
When the Federal Circuit affirms a finding of unpatentability, the patent claims at issue are rendered invalid and unenforceable. Masimo cannot use these specific claims to pursue infringement actions against Apple or any third party. The affirmance carries the same practical weight as if the claims had never been granted, closing the enforcement path for this particular patent asset.
Claims extinguishedWhy patentability appeals at the Federal Circuit rarely succeed
The Federal Circuit reviews patentability findings from the USPTO’s Patent Trial and Appeal Board under a deferential standard — factual findings are upheld unless unsupported by substantial evidence. Reversals require demonstrating legal error or procedural defect, not merely a different reading of the prior art. An outright affirmance, especially without a written opinion, typically signals the appeal raised no compelling new legal argument sufficient to disturb the original finding.
High deference standardAffirmance removes a key Masimo enforcement lever against Apple
For Apple, the Federal Circuit’s affirmance eliminates US6771994B2 as an infringement risk in connection with its pulse oximetry features — particularly relevant given the broader Masimo–Apple dispute over wearable health-sensing IP. Apple’s successful defence at this appellate stage, represented by Fish & Richardson, suggests a well-constructed invalidity record that survived Masimo’s appellate challenge intact.
Enforcement risk removedMasimo retains broader portfolio but loses this claim set permanently
While the loss of US6771994B2 is significant, Masimo holds an extensive pulse oximetry patent portfolio and has pursued Apple across multiple parallel proceedings. The Federal Circuit affirmance forecloses further appeals on these specific claims absent Supreme Court intervention — which is rarely granted. Masimo’s litigation strategy will likely pivot to surviving patents and any trade secret or ITC proceedings still in progress.
Portfolio strategy continuesFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Masimo, Corp. | Company | Medical device company — holder of US6771994B2, pulse oximeter probe-off detectionSearch in Eureka ↗ |
| Defendant | Apple, Inc. | Company | Apple Inc. — consumer electronics company, maker of Apple Watch with blood-oxygen sensing featuresSearch in Eureka ↗ |
| Plaintiff counsel | Jeremiah Helm | Attorney | Counsel for Masimo, Corp.Search in Eureka ↗ |
| Plaintiff counsel | John M. Grover | Attorney | Counsel for Masimo, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Joseph R. Re | Attorney | Counsel for Masimo, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Shannon Lam | Attorney | Counsel for Masimo, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Stephen C. Jensen | Attorney | Counsel for Masimo, Corp.Search in Eureka ↗ |
| Defendant counsel | Lauren Ann Degnan | Attorney | Counsel for Apple, Inc.Search in Eureka ↗ |
| Defendant counsel | Michael John Ballanco | Attorney | Counsel for Apple, Inc.Search in Eureka ↗ |
| Defendant counsel | Robert Courtney Counsel | Attorney | Counsel for Apple, Inc.Search in Eureka ↗ |
| Defendant counsel | Walter Karl Renner Esq. | Attorney | Counsel for Apple, Inc.Search in Eureka ↗ |
| Presiding judge | Judge / | Chief Judge | Court of Appeals for the Federal Circuit — Chief JudgeSearch in Eureka ↗ |
Stipulation of dismissal — official text
The Federal Circuit’s order states simply ‘AFFIRMED’ on the patentability cause — an invalidity/cancellation action. This terse disposition confirms the lower tribunal’s unpatentability finding stands in full; no claims were remanded, narrowed, or preserved. For Masimo, the practical consequence is permanent loss of enforcement rights under US6771994B2. For Apple and the wider market, it signals that the specific probe-off detection claims in this patent no longer represent an IP barrier. The absence of a lengthy written opinion typically suggests the Federal Circuit found no close legal question warranting extended analysis.
US6771994B2 — Pulse Oximeter Probe-Off Detection System
US6771994B2 (application number US10/374303) is a Masimo Corporation patent directed to a pulse oximeter probe-off detection system — a method for determining when a pulse oximetry sensor has been displaced or removed from a patient, thereby preventing false or erroneous blood-oxygen readings. This capability is technically significant in both clinical and consumer wearable contexts, as probe displacement is a leading source of measurement error in non-invasive SpO2 monitoring. The patent falls within the broader domain of physiological monitoring signal processing.
Strategically, probe-off detection represents a core quality-assurance mechanism in any wearable device claiming clinical-grade pulse oximetry — including smartwatches. As Apple integrated SpO2 measurement into Apple Watch, Masimo asserted this and related patents as foundational IP barriers. The Federal Circuit’s affirmance of unpatentability removes this specific patent from the competitive landscape, but the underlying technical problem it addressed — reliable sensor contact detection — remains a live area of patent activity. Competitors and product teams in the wearable health-sensor space should treat adjacent Masimo filings as active risk vectors.
Should your product team run an FTO against Masimo’s pulse oximetry portfolio?
US6771994B2 has been affirmed unpatentable and no longer presents a direct infringement risk. However, any team developing wearable pulse oximeters, SpO2-enabled smartwatches, or clinical patient-monitoring devices should treat this case as a prompt — not a clearance. Masimo holds one of the deepest pulse oximetry patent portfolios in the industry, with numerous surviving US and international filings covering signal processing, sensor design, probe-off detection variants, and motion-artifact rejection. A single invalidated patent does not constitute portfolio-level freedom to operate.
PatSnap Eureka’s FTO Search Agent can map Masimo’s active claim landscape against your specific product architecture — identifying which claims in surviving patents read on probe-off detection logic, sensor attachment methods, or SpO2 signal conditioning. Eureka’s claim monitoring alerts you if Masimo’s continuation filings evolve claim language toward your product’s technical implementation, giving your legal and R&D teams early visibility before commercial launch or scale.
Run a freedom-to-operate analysis on US6771994B2 to assess your product’s exposure
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What this case signals for the wearable health-sensor IP landscape
The Federal Circuit’s affirmance in Masimo v. Apple has direct implications for patent strategy in non-invasive biometric monitoring — one of the most contested technology spaces in consumer health.
Probe-off detection patents face elevated invalidity risk at the PTAB
This outcome suggests that foundational pulse oximetry patents — including signal-quality and probe-off detection methods — are vulnerable to post-grant invalidity challenges, particularly where prior art is well-developed. Companies asserting these patents should conduct rigorous validity assessments before litigation investment, as PTAB findings in this space appear to be holding up on appeal.
Apple’s IPR/post-grant defence playbook is proving highly effective
Apple’s ability to obtain and defend an unpatentability finding through to Federal Circuit affirmance — represented by Fish & Richardson — reinforces a pattern of using post-grant proceedings as a primary defence against NPE and competitor patent assertions in the health-sensor domain. Companies facing Apple on medical-device IP should anticipate aggressive PTAB challenges.
Masimo v Apple — key questions answered
The Court of Appeals for the Federal Circuit affirmed the unpatentability of Masimo’s US6771994B2 on 10 January 2024. The order, docketed as case 22-1894, confirmed the lower tribunal’s invalidity finding in full, extinguishing Masimo’s enforcement rights under that patent.
US6771994B2 covers a pulse oximeter probe-off detection system — a method for identifying when a sensor has been removed or displaced from a patient, preventing false SpO2 readings. Its relevance to Apple Watch stems from Apple’s integration of blood-oxygen monitoring features, which Masimo alleged relied on patented oximetry signal-processing methods.
An affirmance of unpatentability means the patent claims are invalid and unenforceable. Masimo cannot use these claims in future infringement actions against Apple or any other party. The decision is final unless Masimo successfully petitions the U.S. Supreme Court for certiorari, which is rarely granted in patent validity cases.
Masimo was represented by Knobbe, Martens, Olson & Bear, LLP, with attorneys including Joseph R. Re, Stephen C. Jensen, John M. Grover, Jeremiah Helm, and Shannon Lam. Apple was represented by Fish & Richardson LLP, with counsel including Lauren Ann Degnan, Walter Karl Renner, Michael John Ballanco, and Robert Courtney.
No. This ruling applies only to the specific claims of US6771994B2 asserted in this proceeding. Masimo and Apple have been engaged in broader parallel litigation across multiple forums, including district court proceedings and ITC investigations involving different patents and products. The affirmance here eliminates one patent from the dispute but does not resolve the wider IP conflict between the two companies.
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