Focusing Reflected Ultrasound Using Boundary Element Model for Mid-Air Tactile Presentation

Area of Science:

• Acoustics
• Haptics
• Wave physics

Background:

• Mid-air tactile presentation using ultrasound offers advantages like multi-directional sensation and reduced transducer array conflicts.
• Previous methods for ultrasound focusing with curved reflectors often required extensive prior measurements and lacked real-time adaptability.

Purpose of the Study:

• To propose a novel method for focusing reflected ultrasound using curved surfaces for enhanced mid-air tactile feedback.
• To enable real-time focusing on arbitrary locations without pre-measurement of transducer responses.
• To improve focus intensity by integrating target object characteristics into the modeling.

Main Methods:

• Solving the boundary integral equation for the sound field on an element-divided reflector.
• Formulating the relationship between transducer input and reflected sound field for real-time control.
• Incorporating the tactile presentation's target object into a boundary element model to enhance focus intensity.

Main Results:

• Demonstrated successful ultrasound focusing from a hemispherical dome using numerical simulations and experimental measurements.
• Validated the proposed method's ability to achieve focused ultrasound at desired locations.
• Identified regions where sufficient focus intensity could be generated through numerical analysis.

Conclusions:

• The proposed boundary integral equation method effectively achieves ultrasound focusing with curved reflectors for mid-air tactile presentation.
• This approach allows for real-time, adaptable tactile feedback without the need for individual transducer calibration.
• The method shows potential for creating more immersive and precise haptic experiences.