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.
