Electrostatic Multitouch Surface with Segmented Electrodes
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Solution Overview
Problem
Existing touch interface devices struggle to provide differentiated haptic effects to multiple fingertips simultaneously, limiting their ability to create complex interactions such as virtual bumps, holes, and toggle switches, and they often require high energy or high voltages, which are inefficient.
Innovation Solution
A touch interface device with a touch surface featuring first and second electrodes of opposite polarities, generating electrostatic forces that can be modulated at high frequencies to create varying normal and frictional forces on fingertips, allowing for multitouch capabilities and efficient haptic feedback without the need for mechanical parts or high voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If piezoelectric actuators are used to generate mechanical vibration, then haptic feedback can be provided, but energy consumption increases and the system cannot support multitouch with differentiated haptic effects
Solution Approach 1:
The patent replaces mechanical vibration actuators with electrostatic actuation. Instead of using piezoelectric crystals that mechanically vibrate, the system uses electrostatic forces generated by charged electrodes to directly influence the fingertips. This substitution eliminates the need for mechanical moving parts, reduces energy consumption, and enables independent control of haptic effects at multiple touch locations simultaneously.
Solution Approach 2:
The patent divides the touch interface into multiple independently controllable electrode regions. Each region can be actuated with different voltages and frequencies to provide differentiated haptic feedback to multiple fingertips simultaneously. This segmentation allows the system to support multitouch while maintaining low energy consumption through selective actuation of only the regions where touches occur.
2Device complexity
If electrostatic actuation is used to generate vibrations, then no moving mechanical parts are needed, but the forces produced are relatively small and high voltages are required
Solution Approach 1:
The patent applies local quality by concentrating electrostatic forces at specific locations where fingertips make contact. By positioning electrodes directly beneath the touch points and applying voltage only to those regions, the system generates strong localized forces without requiring high voltages across the entire device. This localized approach increases force magnitude at the point of contact while reducing overall energy consumption.
3Ease of operation
If the entire display screen vibrates, then haptic feedback can be provided, but different haptic effects cannot be individually controlled for each fingertip
Solution Approach 1:
The patent segments the touch interface into multiple independently controllable electrode regions. Each region can be actuated with different voltages, frequencies, and waveforms to provide differentiated haptic feedback to multiple fingertips simultaneously. This segmentation enables the system to provide tailored haptic effects to each touch location while maintaining ease of operation through a unified electrostatic actuation mechanism.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the generation of robust, differentiated haptic effects on multiple fingertips, enhancing interaction complexity while reducing energy consumption and voltage requirements, allowing for precise control of forces based on position, velocity, and acceleration.
Implementation Method 1
The first and second electrodes generate an electrostatic force that is imparted on one or more appendages of an operator that touches the touch surface above both the first electrode and the second electrode
Data Source
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AI summary
A touch interface device includes a touch surface, an actuator, and an electrode. The actuator is coupled with the touch surface and is configured to move the touch surface in one or more directions. The electrode is coupled with the touch surface and is configured to impart a normal electrostatic force on one or more appendages of a human operator that engage the touch surface when an electric current is conveyed to the electrode. Movement of the touch surface by the actuator and the electrostatic force provided by the electrode are synchronized to control one or more of a magnitude or a direction of a shear force applied to the one or more appendages that engage the touch surface.