Recent years, spreading smartphones enhance anticipations toward haptic technologies. However, haptic interaction toward digital contents is very much limited. By employing thermal radiation and characteristic of human heat sensation, we focus on novel haptic display which realize virtual haptic sensation in the air without any holdings.

Here we propose novel haptic display which enables us to contact with digital contents in the air without any gloves and holdings. We employ phase shift of heat sensation as virtual haptic contact. The system consists of halogen lamp, pan/tilt mirror, thermal camera, and depth sensor. Halogen lamp emits powerful light to user's hand and the hand is heated by the light. If the temperature of the hand becomes over 45 degree Celsius, the sensation of human changes from hot to pain (from heat sensation to nociceptive sensation). By employing the phase shift, we convey haptic sensation to human. Pan/tilt mirror controls direction of emitted light and on/off movement of reflection mirror controls focus length of emitted light.

When the user put his hand in the air, the system measure the position of the hand. Normal camera and pan/tilt movement of ultrasonic range sensor detect three dimensional position of the hand. The measured position and displaying virtual shape is compared in realtime, and if there is any contact with virtual object, the pan/tilt mirror induces the thermal radiation to the hand. At the same time, based on the distance of the hand, the system slides the reflection mirror and control focus position of the radiation. In the same manner, if there have no contact with virtual object, the radiation is off from the hand.

By using the thermal camera we realize quick control between contact and no contact toward the object. The system controls the radiation to keep temperature on the hand around the 45 degree Celsius, and it also avoids overheating of the hand. Thus the user can feel nociceptive feedback on his hand according to his hand poisition. Around 45 degree Celsius, the sensation of human changes from heat sensation to nociceptive sensation. By employing the characteristic of human we display haptic feeling in the air.

With the system human can contact with digital contents directly through his hands, and in the future he will exert enhanced creativity.

Publications

• Satoshi Saga. HeatHapt:Thermal-Radiation-Based Haptic Display. In Proceedings of AsiaHaptics 2014, 2014.

Acknowledgement

This work is supported by Microsoft Research CORE 10 Project.