Input with a touch panel interface of a small device is typically inaccurate because the touch point is occulded by te user's finger and a user cannot obtain haptic feedback. To overcome this problem, we propose a visuo-haptic system with a rear touch interface to evoke the haptic sensation without using haptic devices. For normal force, the system modifies the shape of a virtual object when the user presses the device from behind. For shearing force, the system produces a mismatch between the speed of the touch point on the rear side, which is hidden by the monitor, and a pointer, which shows a touch point displayed on the monitor. Using the system, we coducted experiments to explore the effect of visuo-haptic interaction of normal and shearing forces with a rear touch interface.The results demonstrated that more than 80% of participants perceived greater stiffness with the deformed model than the model not deformed by normal force. For shearing force, the results showed significant differences in perception based on differing strengths of visual feedback. In addition, the results showed that subtle change of the haptic sensation can be evoked with the visual feedback of deformed hand in place of a cursor.
