Capacitive Touch Sensing Circuit With Segmented Voltage Storage
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Solution Overview
Problem
Current touch sensing systems for capacitance-type touch panels face challenges in accurately detecting touch events and identifying touch points due to limitations in voltage variation detection and signal processing.
Innovation Solution
A touch sensing circuit comprising a voltage storage unit with capacitors and switch elements that generate and amplify corresponding voltages to detect touch events, utilizing a sensing array with interlaced lines and switch units to provide alternating current voltage and integrate signals for precise touch identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional voltage detection methods are used in capacitance-type touch panels, then the system structure remains simple, but the accuracy of touch event detection and touch point identification is insufficient
Solution Approach 1:
The voltage storage unit is segmented into multiple capacitors (first capacitor, second capacitor, third capacitor) and multiple switch elements (first switch element, second switch element). Each component performs a specific function in the voltage generation and detection process, allowing for more precise touch event detection while maintaining a modular and manageable structure.
Solution Approach 2:
The patent introduces a time-based dimension by sequentially controlling the switch elements to connect different capacitors to the first node. This temporal sequencing allows the system to generate distinct voltage patterns for different touch events, enhancing detection accuracy without requiring a physically more complex spatial structure.
2Productivity
If a simple voltage detection circuit is used, then the device complexity is low, but the efficiency of signal processing and touch point identification is insufficient
Solution Approach 1:
The first and second capacitors are pre-charged to different voltages before touch detection. When a touch event occurs, the switch elements rapidly connect these pre-charged capacitors to generate an immediate voltage change at the first node. This preliminary charging action enables fast signal generation and processing, improving productivity without requiring complex real-time computation circuits.
Solution Approach 2:
The switch elements act as intermediaries that control the connection between different capacitors and the first node. By using these switching intermediaries, the system can efficiently route and combine voltage signals from multiple capacitors, enhancing signal processing efficiency while keeping the overall circuit structure manageable through standardized switching components.
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
Enhances the accuracy and efficiency of touch event detection and signal processing, allowing for reliable identification of touch points and improved user interaction in touch panel systems.
Implementation Method 1
The third capacitor is formed between the first and second nodes. When the touch event has occurred, a value of the third capacitor is changed, so that the corresponding voltage at the first node is changed.
Implementation Method 2
Touch between a finger/touch stylus and a touch panel causes a capacitance change and further generates a corresponding voltage.
Data Source
AI summary
A system for displaying images includes a touch sensing circuit. The touch sensing circuit comprises a voltage storage unit for detecting whether a touch event has occurred and generates a corresponding voltage. The voltage storage unit comprises first to third capacitors. The first capacitor has a first terminal coupled to a ground terminal and a second terminal coupled to a first node. The second capacitor has a first terminal coupled to the ground terminal and a second terminal coupled to a second node. When the voltage storage unit detects that a touch event has occurred, the second node is coupled to an AC voltage. The third capacitor is formed between the first and second nodes. When the touch event has occurred, a value of the third capacitor is changed, so that the corresponding voltage at the first node is changed.