Abstract
This disclosure describes a curved-surface capacitive input device that reproduces the tactile behavior of a mechanical scroll wheel within a total assembly stack height of approximately 9.5 mm, making scroll-wheel functionality practical in ultraportable laptop keyboards for the first time. A mutual-capacitance touch strip is formed along the arc of a protruding disk segment rather than on a flat surface, giving the finger the same curved reference geometry as a physical wheel. A linear resonant actuator (LRA) of the type used in smartwatches is bonded to part of the chord of that disk segment and driven with pulse-width-modulated waveform profiles that synthesize click detents, free-spin inertia, and page-turn cues. A rigid post with a silicone sleeve bypasses the actuator and transmits finger force directly into the printed circuit board, where a MEMS accelerometer reads the resulting board flexure as tilt and pressure — providing horizontal scrolling and pressure-graduated zoom with no pivot, encoder, or dedicated force sensor. Scroll displacement is derived from the leading edge of the contact patch rather than its centroid. Specific electrode counts, layer thicknesses, damping durometers, PWM duty cycles, force thresholds, and latency targets are given so that the design can be reduced to practice without further invention.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Kavuru, Madhav, "Virtual Scroll Wheel Input Device with Adaptive Touch Sensing and Modular Haptic Feedback", Technical Disclosure Commons, ()
https://www.tdcommons.org/dpubs_series/11653