Optimization of Tunneling Magnetoresistance Sensor Array-Based Magnetic Eye Tracking System: A Simulation Study

Tunneling magnetoresistance (TMR) sensors are highly sensitive magnetic field detectors with applications in biomagnetic sensing and human–computer interfaces. However, the systematic optimization of TMR sensor structures and array configurations for magnetic eye tracking remains limited. This study presents a simulation-guided approach to optimize TMR sensor arrays for eye tracking. First, a finite element model of a CoFeB/MgO/CoFeB magnetic tunnel junction was developed in COMSOL Multiphysics to optimize the MgO barrier thickness. Simulations from 0.5 to 4.0 nm showed that a 1.5 nm MgO barrier achieved an MR ratio of 285%, a sensitivity of 0.13 Ω·m/A, and a wide linear sensing range. TMR arrays with three to seven sensors were then evaluated using an NdFeB magnetic marker and a spherical eyeball model. The five-sensor array achieved the highest overall performance. Elliptical (O-shape) and sinusoidal (wave-shape) eye trajectories were further simulated using time-dependent magnetic field analysis with an ALE moving mesh. The maximum value method successfully reconstructed both trajectories with good agreement with the original paths. These results demonstrate the feasibility of TMR-based wearable eye tracking for human–computer interfaces.