Walk the independent claim. Apple's grant US11150731B2, "Multi-modal haptic feedback for an electronic device using a single haptic actuator" (issued October 19, 2021; inventors Darya Amin-Shahidi and Alex M. Lee), is a granted patent with a single, clean CPC tag: G06F 3/016, the haptic-feedback class. The narrowness of the classification mirrors the focus of the claim.
The element that does the work is the waveform, not the hardware. The naive way to give a device several distinct tactile sensations — a sharp tap, a long buzz, a textured scroll detent — is to fit several actuators. The claim's contribution is doing it with one, by driving that single actuator with carefully shaped waveforms so the user perceives multiple, distinct "modes." The intelligence is in the drive signal.
What it reads on is the precision haptic engine in Apple's phones, trackpads, and wearables — the components marketed as the Taptic Engine. A single high-quality actuator driven with sophisticated waveforms is exactly Apple's house approach to haptics, and this claim protects the multi-modal output method that approach depends on.
Scope discipline: the claim does not own haptic feedback, and it does not own linear actuators. It protects the recited method of producing multiple distinct haptic modes from a single actuator. A device that achieves variety with multiple actuators — the older, bulkier approach — operates outside this claim. The defensible element is the single-actuator, multi-mode constraint.
Granted status makes this a live consideration for anyone engineering compact haptics. Space and bill-of-materials pressure pushes the whole industry toward fewer actuators doing more, which is precisely the design space this claim sits in — so a freedom-to-operate read should map the drive-waveform method against the claim's limitations.
For a strategist, the tell is the economy of the claim: one actuator, one CPC class, a tightly scoped method. Apple is not claiming the field of haptics; it is claiming the efficient way to do it, which is often the more valuable position as devices shrink.