Touch Panel Driving Apparatus Sensitivity Enhancement
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Solution Overview
Problem
Capacitive touch panel driving apparatuses have low sensing sensitivity due to small changes in sensing capacitance caused by touch motions, leading to voltage saturation issues and difficulty in determining touch events.
Innovation Solution
A touch panel driving apparatus that employs a mutual capacitive or self-capacitive scheme with a single sensing circuit, using a touch control unit and a touch sensing unit to generate and process differential amplification signals based on capacitance changes between transmitting and receiving lines, enhancing sensitivity by amplifying only the difference in sensing capacitance and reducing noise influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the voltage of the excitation signal is increased to increase the output voltage of the amplifier, then the output voltage increases, but voltage saturation occurs where the output voltage is out of the input voltage range of the converter
Solution Approach 1:
The patent segments the sensing process into two distinct modes: mutual capacitive sensing (using both transmitting and receiving lines) and self-capacitive sensing (using only receiving lines). This segmentation allows the system to process different types of capacitance changes through dedicated sensing circuits, enabling accurate detection without voltage saturation while maintaining flexibility in handling various touch scenarios
Solution Approach 2:
The patent changes the sensing parameters by implementing dual sensing modes that measure different capacitance characteristics. The mutual capacitive mode measures capacitance between transmitting and receiving lines, while the self-capacitive mode measures capacitance of receiving lines alone. This parameter change allows the system to operate within safe voltage ranges while achieving the required output voltage for accurate conversion
2Measurement precision
If the capacitance of the sensing capacitor is increased to improve sensing sensitivity, then the sensing sensitivity increases, but the parasitic capacitor on each line remains larger than the sensing capacitor
Solution Approach 1:
The patent extracts and eliminates the harmful effect of parasitic capacitors by implementing differential sensing. The sensing circuits are designed to measure only the change in sensing capacitance (ΔCs) caused by touch motions, while automatically rejecting the parasitic capacitance components. This extraction approach allows accurate touch detection even when parasitic capacitance is larger than the sensing capacitor
Solution Approach 2:
The patent implements feedback mechanisms where the sensing circuits continuously monitor capacitance changes and adjust their operation accordingly. The dual-mode sensing system uses feedback to determine which sensing mode to employ and to calibrate the measurements, ensuring accurate touch detection while compensating for parasitic capacitance effects
3Device complexity
If a single sensing circuit is used to reduce device complexity, then the device complexity decreases, but the sensing sensitivity and accuracy are insufficient
Solution Approach 1:
The patent implements a universal sensing circuit design that can perform multiple sensing functions through software control. The same physical sensing circuit can operate in mutual capacitive mode or self-capacitive mode depending on the touch scenario, eliminating the need for separate dedicated circuits for each sensing type while maintaining high sensing sensitivity and accuracy for both modes
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 significantly improves touch sensitivity by widening the dynamic range of sensing voltage, increasing accuracy, and reducing external noise interference, allowing for more precise detection of touch events with a single sensing circuit.
Implementation Method 1
generating the digital touch information on the basis of change of a capacitance between two transmitting lines and one receiving line or generating the digital touch information on the basis of change of a capacitance of each of the receiving lines
Data Source
AI summary
Disclosed are a touch panel driving apparatus and a display device including the same, which lead to the enhancement of sensing sensitivity. The touch panel driving apparatus includes a touch control unit and a touch sensing unit. The touch sensing unit is connected to the receiving lines, and generates the digital touch information on the basis of change of a capacitance between two transmitting lines and one receiving line or generates the digital touch information on the basis of change of a capacitance of each of the receiving lines to supply the digital touch information to the touch control unit, according to the sensing control signal.