The Legal Dispute Over Apple Watch’s Blood Oxygen Sensor Technology

A significant legal battle has unfolded between Apple and Massimo Corporation regarding patented pulse oximetry technology used in certain Apple Watch models to measure blood oxygen levels. The contentious dispute spans multiple case venues as the parties pursue their respective positions.

The Origins of Massimo’s Pulse Oximetry Patents

Massimo was founded in the late 1990s by entrepreneur Joe Kiani, a graduate of San Diego State University with a master’s degree in electrical engineering. The company focused on developing pulse oximeters capable of providing accurate oxygen saturation readings even when patients moved, aiming to overcome limitations of earlier finger-clip devices.

Over the next two decades, Massimo obtained a portfolio of patents covering techniques using light absorption characteristics to reliably calculate oxygen levels during motion. The company has initiated legal action against other companies to enforce its patents, resulting in settlements to license the technologies.

Litigation Initiated Over Apple Watch

As wearable health technology emerged, Apple hired multiple former Massimo employees, including some who had worked on the blood oxygen monitoring technology. Then in 2015, Apple released Apple Watch models with the ability to measure blood oxygen saturation levels.

Person about to touch a smart watch

Massimo responded by filing complaints against Apple in January 2020 in federal court (Masimo Corporation et al. v. Apple Inc., CDCA-8:20-cv-00048) alleging patent infringement and trade secret misappropriation related to 12 patents. It followed with a separate case at the U.S. International Trade Commission (ITC) in June 2021 (Certain Light-Based Physiological Measurement Devices and Components Thereof, ITC-337-TA-1276) over 5 of those patents, seeking to ban importation of the Apple Watch.

In January 2023, the ITC ruled in favor of Massimo and issued an exclusion order prohibiting import of the infringing Apple Watch Series 6 models related to two patents – No. 10,912,502 and No. 10,945,648. The key infringed claim limitations involved specific arrangements of light sensors, opaque materials, and protrusions.

Apple’s “Redesign” to Circumvent ITC Ban

Rather than remove the blood oximetry hardware entirely, Apple implemented design changes to disable the functionality in new imported watches through combined software and hardware modifications during manufacturing. 

This included coding a new designation at the factory level, as well as modifying the software pairing process between the watch and iPhone to disable pulse oximetry when detecting that hardware designation.

Apple then secured a ruling from U.S. Customs and Border Protection (CBP) in January 2024 that these design alterations were sufficient to avoid infringing Massimo’s patents. The CBP’s Exclusion Order Enforcement Branch determined the modified watches no longer met the claim limitations of being “programmed to” or “configured to” conduct blood oxygen readings and reporting, since those functions were now disabled by default.

While Massimo could circumvent software restrictions on the modified devices to reactivate readings, CBP deemed those unauthorized modifications an “alteration” taking the redesigned watches outside the scope of Massimo’s patent claims and the ITC exclusion order.

Pending Appeals and Unresolved Damages

The dispute remains ongoing, however. Apple appealed the original ITC decision to the Federal Circuit, where Apple is contesting the underlying infringement and validity findings in an upcoming appeal briefing.

In parallel district court litigation (Masimo Corporation et al. v. Apple Inc., CDCA-8:20-cv-00048), the patent infringement case to determine potential damages owed for previously imported Apple Watches having active pulse oximetry functionality remains stayed. Massimo’s litigation position has been impacted after the U.S. Patent Trial and Appeal Board invalidated many of the originally asserted patent claims, though some claims survive. Massimo’s trade secret claims against Apple will also face retrial in 2024 after a hung jury last year.

The dispute highlights the complexity of enforcing patents against a major technology company’s product line. While Massimo initially prevailed at the ITC, Apple implemented design changes to maintain its smartwatch functionality as the cases continue through appeal processes seeking final resolution over the next years.

About the Author

Matthew McKinney practices in all areas of intellectual property, representing a wide range of clients in connection with the acquisition, transfer, enforcement, and defense of their intellectual property rights.

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