Touch Screen Flat Panel Display Electrode Multiplexing
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Solution Overview
Problem
Current capacitive touch screens face challenges in achieving accurate and efficient touch positioning due to high costs, complex electrode structures, and interference from sensing lines, which affect display quality and reliability.
Innovation Solution
A touch screen FPD design that uses a multiplexer or signal loading and merge circuit to enable electrodes to transmit both display driving and touch signals, applying touch signals to multiple electrode lines simultaneously and detecting changes across these lines to improve positioning accuracy and reduce detection time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two layers of fine and close electrodes are used for fine positioning in digital capacitive touch screens, then positioning accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The display electrodes are made to serve dual functions: displaying images and detecting touch positions. The same electrode lines that display visual content are also used as sensing elements for touch detection, eliminating the need for separate fine-pitch sensing electrode layers and reducing manufacturing complexity while maintaining positioning accuracy
Solution Approach 2:
The invention merges the display function and touch sensing function into a single electrode structure. By combining the display electrode lines with touch detection functionality, the patent eliminates the need for separate sensing electrode layers, thereby reducing manufacturing cost while achieving fine positioning accuracy
2Adaptability or versatility
If sensing lines are added to the touch screen, then touch detection capability is improved, but display quality deteriorates due to reflection and nonuniformity
Solution Approach 1:
The display electrodes perform both display and touch detection functions simultaneously. By using the existing display electrode lines for touch sensing, the patent eliminates the need for additional dedicated sensing lines that would cause reflection and display nonuniformity, thereby maintaining display quality while enabling touch detection
Solution Approach 2:
The invention extracts the touch detection function from the display structure by using the display electrodes themselves for sensing. This eliminates the need for separate sensing line structures that would be embedded in the display and cause visual artifacts such as reflection and nonuniformity
3Measurement precision
If two layers of sensing lines are used for fine positioning, then positioning accuracy is improved, but detection and calculation time increases
Solution Approach 1:
The display electrodes serve dual purposes as both display elements and touch sensors. By using the existing display electrode lines for touch detection, the patent eliminates the need for separate two-layer sensing electrode structures, thereby reducing the complexity of detection circuits and calculation requirements while maintaining fine positioning accuracy
Solution Approach 2:
The invention merges display and touch sensing functions into the same electrode structure, eliminating the need for separate sensing line layers. This integration reduces the number of detection channels and simplifies the calculation process required for determining touch position, thereby reducing detection and calculation time while maintaining positioning accuracy
4Adaptability or versatility
If electrodes are connected to both display driving circuit and touch system circuit from two ends, then touch sensing capability is enabled, but device complexity and cost increase
Solution Approach 1:
The display electrodes are made to serve dual functions by connecting them to both display driving circuits and touch system circuits. The same electrode lines that carry display signals are also used for touch detection, enabling touch sensing capability while avoiding the need for separate dedicated sensing electrode structures and their associated complex lead arrangements
Solution Approach 2:
The invention merges the display driving function and touch sensing function into the same electrode structure. By using the display electrode lines for both purposes and connecting them to both display driving circuits and touch system circuits, the patent enables touch sensing while reducing the overall complexity compared to having separate sensing electrode layers with independent lead connections
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 approach enhances touch positioning accuracy, reduces detection time, and allows for multi-touch functionality while maintaining normal display functionality, addressing the limitations of existing capacitive touch screens.
Implementation Method 1
when a finger of a human touches the touch screen, the finger forms a coupling capacitor with some electrodes on the touch screen, and a leakage current flows from the coupling capacitor
Implementation Method 2
A touch excitation signal is applied to each electrode, and when a finger of a human touches the touch screen, the finger forms a coupling capacitor with some electrodes on the touch screen, and a leakage current flows from the coupling capacitor
Data Source
AI summary
A touch screen flat panel display (FPD) is provided, which includes a display screen, a display driving circuit, a touch system circuit, and the like. Related circuits in the touch screen FPD enable electrodes of the display screen to transmit display driving signals as well as touch signals, that is to say, the display driving and the touch detection multiplex the electrodes of the display screen, such that the FPD is not only used for normal display but also used for realizing touch detection. By applying the touch signal simultaneously to detecting lines and non-detecting lines, the flow of the touch signal between the detecting lines and between the detecting line and the non-detecting line is reduced, thus controlling the flow direction of the touch signal, and increasing the accuracy of determining touched electrodes.