FeelPen: A Haptic Stylus Displaying Multimodal Texture Feels on Touchscreens

The ever-emerging mobile market induced a blooming interest in stylus-based interactions. Most state-of-the-art styluses either provide no haptic feedback or only deliver one type of sensation, such as vibration or skin stretch. Improving these devices with display abilities of a palette of tactile feels can pave the way for rendering realistic surface sensations, resulting in more natural virtual experiences. However, integrating necessary actuators and sensors while keeping the compact form factor of a stylus for comfortable user interactions challenges their design. Consequently, it limits the scientific knowledge of relevant parameters for rendering compelling artificial textures for stylus-based interactions. Here, we developed FeelPen, a haptic stylus that can display multimodal texture properties (compliance, roughness, friction, and temperature) on touchscreens. We created a set of artificial textures and conducted a user study in which human participants rated these textures based on various perceptual adjectives describing their haptic properties. Afterward, we extracted the dominant perceptual dimensions of these textures using the semantic differential method. Our results revealed four major tactile dimensions, with the first two related to surface textural properties, and the third and fourth dimensions linked to material softness and coldness, respectively. Our unique design and experimental results have the potential to open new perspectives for stylus-based interactions on future touchscreens.