Models of Physical Comfort Design for Ear-Related Wearables Integrated with Ear Anthropometry

A systematic framework is proposed to model physical comfort in ear-related wearable devices. As ear-worn products evolve from single-purpose audio transmission to multifunctional interaction and biosignal monitoring, physical comfort has become a critical determinant of user acceptance and long-term wear compliance. The external ear presents distinctive ergonomic challenges due to its limited contact area, complex geometry, heterogeneous tissue composition, and high sensory sensitivity, rendering conventional general ergonomics-based comfort models insufficient. This chapter introduces static and dynamic comfort perception models that attribute discomfort to mismatches between product parameters and the tolerance thresholds of ergonomic design factors (EDFs). Dynamic comfort is further shaped by usage-related variables, including wearing motivation, duration, and environmental context. A human-product interaction path model is developed to illustrate how anatomical variability, such as bilateral asymmetry, sex differences, and age-related morphological changes, constrains one-size-fits-all design approaches. Key EDFs are extracted through semi-structured interviews and structured questionnaires, and factor analysis is employed to categorize them into three principal dimensions: auricle shape-structure, external acoustic meatus (EAM) shape-structure, and transitional anatomical structures. The proposed framework provides theoretical and methodological foundations for predicting physical comfort, defining tissue deformation thresholds, and guiding the ergonomic design of inclusive ear-related wearable devices.