Developing predictive models of user affective responses and a grading system for evaluating multi-crease patterns in foldable smartphones

This study investigated the user affective (Kansei) evaluation of foldable smartphone creases. Twenty-five participants assessed twenty foldable smartphone display prototypes with various multi-crease patterns, for four affective dimensions (crease invisibility, flawlessness, luxuriousness and harmoniousness) using an 11-point rating scale, and, for overall goodness using a 7-point adjective-anchored scale. The adjectives for overall goodness evaluation represented different crease grade categories. Principal component analysis identified a composite measure, termed Affective Quality Score (AQS), which integrates the four affective dimensions. A regression model was developed to predict AQS based on physical features of a multi-crease pattern. Also, a crease grading system was established that determines the adjective grade category of a multi-crease pattern using its AQS. The regression model along with the crease grading system enables predicting and grading the affective quality of a given multi-crease pattern. The research outcomes would support design goal setting and continuous quality improvement for foldable smartphone products.