Fast-response electrophoretic display via particle size engineering

Electrophoretic display (EPD) technology holds promise for video-rate applications but is limited by slow response speed and low contrast. This study demonstrates particle size engineering as a transformative strategy to achieve video-rate performance. Copper chromite black spinel (CCBS) particles with stable zeta potential were prepared through controlled ball milling and surface modification. Through experiments, CCBS-60 h particles were prepared, reducing their black reflectivity by 44.6%, increasing the contrast from 3.46 to 4.98, and achieving a rapid response time of 46 ms. This 46 ms response approaches the threshold for 24 fps video playback. Reducing the response time of electrophoretic displays to near the video-response threshold enables high-frame-rate video presentation of EPDs. High contrast and fast response speed offer application potential for video-level response. Since ball milling can no longer make the electrophoretic particles reach a smaller size, in order to further study the influence of particle size on the display effect, this study employed COMSOL Multiphysics simulations to analyze the force distribution of black particles with varying sizes within the microcup and their motion trajectories under multiphysics interactions. The results show that particle size affects the display performance of electrophoresis through three mechanisms: charge-mass ratio, fluid resistance, and agglomeration behavior.