Hovering Touch Sensing Apparatus Circuit Isolation
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Solution Overview
Problem
The challenge in touch control technologies is the mutual interference between display and touch control circuits in thin and compact panels, which affects the signal-to-noise ratio of capacitance measurements, limiting the measurement distance and sensitivity, especially for 3D gesture touch control.
Innovation Solution
A hovering and touch sensing apparatus with a touch sensing electrode matrix, a system circuit, and a touch control circuit, where a capacitance-exciting signal is applied through a larger conductor to enhance measurement sensitivity, forming capacitors between the object and electrodes, and preventing common current loops to isolate noise from the system circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the panel is made thinner and more compact to improve portability, then the device size is reduced, but mutual interference between display circuit and touch control circuit increases
Solution Approach 1:
The patent divides the electrical system into two independent power domains: system power source for display circuit and touch control power source for touch control circuit. This segmentation prevents mutual interference by isolating the current paths while maintaining physical compactness.
Solution Approach 2:
The patent introduces a specific conductor as an intermediary element that couples the touch control circuit to the display circuit through capacitance coupling rather than direct electrical connection. This intermediary structure allows signal transmission while blocking harmful interference currents.
2Adaptability or versatility
If the measurement distance between stylus and device is increased to enable 3D gesture control, then gesture recognition capability is improved, but the signal to noise ratio of capacitance measurement decreases
Solution Approach 1:
The specific conductor acts as an intermediary that amplifies the capacitive coupling effect between the stylus and touch sensing electrodes. By providing an additional capacitive path through the conductor, the signal strength is enhanced while maintaining measurement precision at increased distances.
Solution Approach 2:
The patent changes the electrical parameters of the system by introducing a dedicated capacitance-exciting signal source that operates at specific frequencies. This allows optimization of the capacitive coupling parameters to maintain signal-to-noise ratio even when measurement distance increases for 3D gesture recognition.
3Device complexity
If common current loop is present between system power source and touch control power source, then circuit design is simplified, but noise from system circuit interferes with touch control measurement
Solution Approach 1:
The patent segments the power supply system into independent touch control power source and system power source, each with separate ground references. This segmentation eliminates common current loops that would allow noise propagation while maintaining manageable circuit complexity through modular design.
Solution Approach 2:
The patent extracts the touch control circuit's power and ground connections from the system power network, creating an isolated power domain. This extraction removes the noise coupling path while the specific conductor provides the necessary electrical connection for functionality.
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 solution enhances the signal-to-noise ratio and measurement distance, enabling more precise hovering and touch sensing operations by effectively applying capacitance-exciting signals and isolating noise, thus improving the sensitivity and accuracy of touch control.
Implementation Method 1
a first capacitor is formed between the operation object and the first specific conductor
Implementation Method 2
a second capacitor is formed between the operation object and the respective one of the touch sensing electrodes
Data Source
AI summary
A hovering and touch sensing apparatus includes a plurality of touch sensing electrodes, a system circuit and a touch control circuit. When an operating object approaches to or touches the touch sensing electrodes for hovering or touch sensing operation, there is no common circuit loop between the system circuit and the touch control circuit to prevent the influence of the system circuit to the touch-sensing circuit. Besides, the touch control circuit sends a capacitance-exciting signal to the operating object through a first specific conductor of the system circuit, thus more effectively send the capacitance-exciting signal to the operating object and enhance the preciseness for sensing the touch sensing signal.