Or trifling matters like clips working on an entirely different principle (transmission vice reflection) than the method which remains patent encumbered.
Certainly it works on a different principle than that which is patented. At the same time, IANAL, and if the stakes are large enough the question might need an adjudicated answer.
Adjudicated answers, also known as patents, have been separately issued for these very different techniques to accomplish the same underlying goal. The transmission patents are expired for quite sometime however, which is why devices using them can be made cheaply.
Not really. $15 pulse oximeters on Amazon are coming straight out of China from fly by night companies in a country that doesn't particularly care about IP law, and even when they do make it amazingly hard for a foreign company with even the most absolute, solid, novel patents to fight against a Chinese company blatantly and openly infringing.
Trying to frame this as a money grab from Masimo is overly defensive of Apple.
None of these pulse oximeters on Amazon from China are violating these worn device patents because those pulse oximeters don't use an array of emitters, and heavily process the reflected light results. Wearable pulse ox is an entirely different tech stack as finger clamp pulse ox.
Yeah finger clamps shine through the finger completely. They don't use reflected light.
They are much more accurate for this reason but also more annoying to wear. I think the only daily-wearable one that works this way is the Oura ring.
I'm surprised how well it still works on a watch though. I never tried Apple's implementation as I don't have an apple phone to pair it with, but my galaxy watch 6's SpO2 works pretty decently compared to a finger clamp one, considering it is much harder to do it on the wrist.