Hinge Gestures: Leveraging Foldable Phone Hinges to Enrich Dual-Screen Tactile Interaction

Paper Title

Hinge Gestures: Leveraging Foldable Phone Hinges to Enrich Dual-Screen Tactile Interaction

Publication Info

• Topic area: Interaction design for foldable phones
• Keywords: Foldable phones, hinge gestures, dual-screen interaction, tactile interaction, menu design, thumb reachability, user study, input techniques, mobile interaction, UI design

Background and Problem

• Problem / challenge: Foldable phones present challenges in one-handed dual-screen interaction due to thumb reachability limitations, grip adjustments, and screen real estate constraints caused by traditional menu placements.
• Significance: Addressing these challenges can enhance usability, reduce physical effort, and better leverage the unique form factor of foldable phones.
• Motivation and related work: Prior research explored fold gestures, touch gestures, and mid-air interactions but largely ignored the hinge as an interactive area. Existing studies treated the hinge as an obstacle rather than a functional input zone, leaving a gap in understanding its potential for enriching interaction.

Solution

• Proposed approach: Introduce hinge gestures and hinge menus as novel interaction techniques for foldable phones, leveraging the hinge as a tactile and interactive zone.
• Novelty:
  1. Characterization of thumb-reachable areas and grip postures for foldable phones at various fold angles.
  2. Definition and evaluation of hinge gestures (tap-tap, swipe) performed on, to, from, or across the hinge.
  3. Design and empirical validation of hinge menus, showing their advantages over traditional linear menus.
• Procedure and key techniques:
  1. Conduct four user studies to analyze grip, reachability, hinge gesture performance, and hinge menu usability.
  2. Evaluate hinge gestures (tap-tap, swipe) in terms of speed, accuracy, and user preference.
  3. Develop hinge menus combining hinge gestures for menu activation and item selection.
  4. Compare hinge menus with traditional linear menus in dual-screen scenarios.

Results

• Concrete findings:
  • Hinge gestures (tap-tap, swipe) are fast (completion times <300ms) and accurate (error rates <5%).
  • Hinge menus outperform linear menus in speed (e.g., SwipeFrom→Tap: 910ms vs. LinearLeft: 1236ms) and error rates (e.g., SwipeTo→Tap: 0.5% vs. LinearLeft: 3.1%).
  • Thumb rest positions are typically on the bottom screen, influencing gesture performance.
• Advantage over baselines:
  • Hinge menus reduce physical demand, effort, and frustration compared to linear menus.
  • Hinge gestures leverage tactile feedback from the hinge, enhancing precision and usability.
• Experiments / evaluation:
  • Study 1: Examined grip and thumb-reachable areas across fold angles (12 participants).
  • Study 2: Validated pointing performance on the hinge (12 participants).
  • Study 3: Characterized hinge gestures in terms of speed, accuracy, and user preference (12 participants).
  • Study 4: Compared hinge menus with linear menus in dual-screen scenarios (12 participants).
• Limitations and future work:
  • Limited participant diversity (right-handed, young adults).
  • Focused on thumb input; future work should explore bimanual, stylus, and alternative interaction styles.
  • Conducted on a single foldable phone model; results may vary with other devices.

Summary

This paper introduces hinge gestures and hinge menus as novel interaction techniques for foldable phones, leveraging the hinge as a tactile and interactive zone. Four user studies demonstrate that hinge gestures are fast, accurate, and preferred by users, while hinge menus outperform traditional linear menus in speed, accuracy, and user satisfaction. These findings provide empirical evidence and practical guidelines for designing interactions that fully utilize the unique affordances of foldable phones, paving the way for enriched mobile interaction paradigms.