Auxiliary Capacitance-Exciting Signal for Touch Sensing Noise Isolation
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Solution Overview
Problem
The increasing thickness and compactness of touch control panels in mobile electronic devices lead to mutual interference between display and touch control circuits, necessitating an enhancement in signal-to-noise ratio for capacitance measurement to support 3D gesture touch control and improve measurement distance between stylus/finger and device.
Innovation Solution
A hovering and touch sensing apparatus with an auxiliary capacitance-exciting signal system, comprising a touch sensing electrode matrix, system and touch control circuits, where a specific conductor with a larger area is used to generate and apply alternating signals, forming capacitors that enhance measurement sensitivity and prevent noise interference between the touch control and system circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the touch control panel becomes thinner and more compact, then the device structure is improved, but mutual interference between display circuit and touch control circuit increases
Solution Approach 1:
The patent divides the sensing system into two independent parts: a first specific conductor for generating capacitance-exciting signals and touch sensing electrodes for receiving sensing signals. This segmentation isolates the signal generation function from the sensing function, preventing mutual interference between display and touch control circuits while maintaining panel compactness.
Solution Approach 2:
The patent introduces a first specific conductor as an intermediary element between the display circuit and touch sensing electrodes. This conductor acts as a mediator that generates capacitance-exciting signals without being part of the display circuit or touch control circuit, thereby eliminating direct interference paths while enabling effective signal transmission.
2Length of stationary object
If the measurement distance between stylus and device is increased, then 3D gesture touch control capability is improved, but the signal to noise ratio of capacitance measurement decreases
Solution Approach 1:
The patent transitions from traditional direct-contact touch sensing to capacitance-based sensing using a first specific conductor that generates electric fields in three-dimensional space. This dimensional change enables detection of hovering gestures at different distances without direct contact, improving 3D gesture control capability while maintaining signal integrity through field-based measurement.
Solution Approach 2:
The patent changes the measurement parameter from direct electrical contact to capacitive coupling through air gap. By measuring capacitance changes caused by proximity of conductive objects to the first specific conductor, the system can detect hovering gestures at various distances with high signal-to-noise ratio, enabling precise 3D gesture recognition.
3Device complexity
If a common current loop exists between system power source and touch control power source, then circuit simplicity is maintained, but noise interference in capacitance measurement increases
Solution Approach 1:
The patent extracts the capacitance-exciting signal generation function from the touch control circuit by using a first specific conductor connected to system power source. This separation removes the common current loop between system and touch control power sources, eliminating noise interference paths while maintaining circuit simplicity through functional decomposition.
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 effectively increases the signal-to-noise ratio and measurement distance, enabling precise hovering and touch sensing operations by isolating the touch control circuit from system noise and applying capacitance-exciting signals more effectively to the operation object, thus enhancing the 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 with auxiliary capacitance-exciting signal includes a plurality of touch sensing electrodes, a system circuit and a touch control circuit. When an operating object approaches or touches the touch sensing electrodes for hovering or touch sensing, there is no common circuit loop between the system circuit and the touch-sensing circuit to prevent the influence of the system circuit to the touch control circuit. The touch control circuit sends a capacitance-exciting signal to the operating object through a first specific conductor. The touch control circuit sends an auxiliary capacitance-exciting signal to a selected touch-sensing electrode and a touch-sensing circuit receives a touch sensing signal from the selected touch-sensing electrode.