Capacitance Sensing Device for Force and Proximity
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Solution Overview
Problem
Conventional pressure touch control panels and human tactile-proximity devices face high costs, difficult assembly, high power consumption, and poor accuracy, particularly in sensing force and proximity, with existing technologies unable to effectively integrate microelectromechanical sensors and artificial skin materials.
Innovation Solution
A sensing device comprising an upper and lower substrate with a resilient dielectric layer, electrode layers, and a capacitance sensing circuit that sends excitations signals to electrodes to perform force and tactile-proximity sensing, utilizing a self-capacitance sensing circuit to reduce the number of sensing electrodes required and enhance sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If microelectromechanical sensors are integrated at edge or corner of display panel, then force sensing capability is achieved, but cost increases and assembly difficulty increases
Solution Approach 1:
The patent replaces mechanical microelectromechanical sensors with an electrical field-based sensing system using capacitor electrodes. The force sensing is achieved through detecting capacitance changes caused by dielectric layer deformation, eliminating the need for complex mechanical sensor integration and reducing assembly complexity while maintaining force sensing capability.
Solution Approach 2:
The capacitor electrodes serve multiple functions: they enable both proximity sensing (through self-capacitance measurement) and force sensing (through mutual capacitance measurement with dielectric layer deformation). This multi-functionality eliminates the need for separate sensor systems, reducing overall device complexity and assembly requirements.
2Measurement precision
If artificial skin with conductive rubber, conductive sponge, or carbon fiber is used, then force sensing is achieved, but power consumption increases and accuracy deteriorates
Solution Approach 1:
The patent replaces resistive artificial skin materials with a capacitive sensing system that measures force through capacitance changes rather than resistance changes. This electrical field-based approach eliminates the high power consumption associated with maintaining current flow through conductive materials while improving measurement accuracy through precise capacitance detection.
Solution Approach 2:
The sensing system uses periodic excitation signals to drive the capacitor electrodes, enabling AC-coupled capacitance measurement. This periodic action allows for high-precision force sensing while maintaining low average power consumption, as the system only consumes significant power during brief measurement intervals rather than continuously.
3Ease of operation
If conventional pressure touch control panel is used, then basic touch control is achieved, but proximity sensing capability is lost
Solution Approach 1:
The capacitor electrode system performs both self-capacitance measurement for proximity sensing and mutual capacitance measurement for touch control functionality. By utilizing the same physical structure for multiple sensing modes, the system achieves versatility without adding separate components, maintaining ease of operation while enabling proximity sensing capability.
Solution Approach 2:
The sensing system segments the measurement process into different operational modes (proximity sensing mode and touch control mode) that can be selectively activated. This segmentation allows the system to optimize performance for each specific function while using the same underlying hardware infrastructure.
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
The solution provides a cost-effective, accurate, and flexible device for force and tactile-proximity sensing, capable of detecting touch and proximity with reduced power consumption and improved accuracy, suitable for various applications including touch displays and robotic systems.
Implementation Method 1
a resilient dielectric layer arranged between the upper substrate and the lower substrate parallel to the upper substrate, and the resilient dielectric layer being compressively deformed under pressure, and restoring to original shape and volume if pressure is not present
Implementation Method 2
a capacitance sensing circuit configured to send a touch control capacitance-exciting signal to at least one selected first sensing electrode sequentially or randomly, and obtain a tactile-proximity sensing signal from the selected first sensing electrode
Data Source
AI summary
A sensing device for force and tactile-proximity sensing includes an upper substrate, a lower substrate, a first electrode layer having a plurality of first sensing electrodes, a second electrode layer having at least one second sensing electrode, a dielectric layer arranged between the upper substrate and the lower substrates, and a capacitance sensing circuit. In tactile-proximity sensing operation, the capacitance sensing circuit sends a touch control capacitance-exciting signal to a selected first sensing electrode and obtains a tactile-proximity sensing signal therefrom, wherein an tactile-proximity auxiliary signal with same phase as the touch control capacitance-exciting signal is sent to the at least one corresponding second sensing electrode. In force sensing operation, the capacitance sensing circuit sends a force capacitance-exciting signal to the corresponding second sensing electrode and obtains a force sensing signal therefrom, wherein a force counter-exciting signal is also sent to the selected first sensing electrode.