Comment by nomel

It's literally a voice coil with a mass on it. Literally anyone who has ever played with a solenoid, and hooked it up to a speaker, has made one. I did it when I was a kid, decades ago, and watched it vibrate on the table and in my hand. When I tried the first haptic thing I knew exactly how they did it. It's so incredibly obvious I don't understand how it's even patentable, with all the prior "make thing vibrate with electromagnet" work.

It's not really "high tech", it's just tuned well, with some high power for the size.