Haptic Display Electrode Layering for Multi-Point Sensing
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Solution Overview
Problem
Existing touch interfaces for surface haptic devices lack effective multi-point haptics, as they either vibrate the entire device, leading to non-independent haptic experiences for different fingers, or struggle with localized electrostatic actuation due to challenges in electrode design and sensing integration.
Innovation Solution
The implementation of 'simultaneous sensing and actuation' using mirrored electrodes, where a top layer provides haptic effects and a bottom layer senses touch locations, ensuring strong capacitive coupling and independent haptic control for multiple fingers through aligned electrode patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If electrostatic actuation is used to generate localized vibrations at the fingertip, then haptic effects are localized to the touch surface, but it is difficult to make low-resistance electrical connection to electrodes not near the edge of the screen
Solution Approach 1:
The patent moves electrodes from the front surface (2D plane) to the rear surface of the substrate, adding a dimensional aspect to the electrode arrangement. This allows edge-connected electrodes to provide haptic effects at remote locations through the substrate, solving the connection difficulty while maintaining localized haptic effects.
Solution Approach 2:
The patent divides the electrode system into two separate surfaces: front surface electrodes for haptic actuation and rear surface electrodes for sensing and electrical connection. This segmentation allows independent optimization of each function, with rear electrodes easily connected at edges and front electrodes providing localized haptic effects.
2Adaptability or versatility
If multiple electrodes are used on the same surface for haptics and sensing, then multi-point haptics is supported, but electrostatic haptics and projected capacitance sensing interfere with each other
Solution Approach 1:
The patent separates haptics and sensing onto different surfaces (front and rear), eliminating the electrostatic interference that occurs when both functions share the same surface. This spatial separation maintains multi-point haptics capability while ensuring reliable sensing.
Solution Approach 2:
The patent segments the touch interface into distinct functional layers: front surface electrodes dedicated to haptic actuation and rear surface electrodes dedicated to sensing. This functional segmentation eliminates cross-interference between the two systems while maintaining full multi-point capability.
3Device complexity
If a single electrode layer is used for both haptics and sensing, then device complexity is reduced, but scratches on the top surface compromise haptic functionality
Solution Approach 1:
The patent segments electrodes into two separate layers: front surface electrodes for haptics and rear surface electrodes for sensing. This allows the sensing function to continue operating even when front surface electrodes are scratched or damaged, as the rear electrodes remain protected and functional.
Solution Approach 2:
The patent provides backup sensing capability through rear surface electrodes that are protected from scratches. This beforehand cushioning ensures that sensing functionality is maintained even when the front surface electrodes are compromised by physical damage.
4Force
If the entire device vibrates to provide haptic feedback, then haptic effects are easily felt, but each fingertip experiences the same effect rather than independent haptics
Solution Approach 1:
The patent segments the haptic actuation to individual electrode locations rather than whole-device vibration. Each electrode can be independently controlled to provide localized haptic feedback at specific touch points, enabling true multi-point haptics where each fingertip experiences independent effects.
Solution Approach 2:
The patent transitions from whole-device vibration (3D mechanical vibration) to localized electrostatic actuation at electrode surfaces. This allows independent control of haptic effects at multiple discrete locations simultaneously, providing true multi-point haptic capability.
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
This approach enables reliable multi-point haptics by ensuring each finger experiences independent haptic effects and accurate sensing, even with scratches compromising the top surface electrodes, while maintaining high signal-to-noise ratios and resolving ghost touch misidentifications.
Implementation Method 1
electrostatic actuation has been explored as a means to generate vibrations localized to the fingertip
Implementation Method 2
Senseg Ltd. makes use of electrostatic forces to create vibrations of the fingertip
Implementation Method 3
ensuring strong capacitive coupling and independent haptic control for multiple fingers through aligned electrode patterns
Data Source
AI summary
Touch interface devices having systems and methods for producing multi-point haptics utilizing simultaneous sensing and actuation are disclosed. In a first configuration, two layers of electrodes are used, including a top layer for haptics near a touch surface of an insulating substrate and a bottom layer for sensing at the bottom surface of the insulating substrate, with the two electrode sets have substantially the same pattern as one another. In a second configuration, a single array of electrodes is used near a touch surface of an insulating substrate and serves as both surface haptic devices and sensing devices.