In-cell Multi-touch Display Panel System with Shared Conductor Lines
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Solution Overview
Problem
The increasing image resolution of display panels limits the display frame rate, making it difficult to perform both image displaying and touch sensing efficiently in high-resolution capacitive touch systems, particularly due to the need for time-sharing between display and touch detection operations.
Innovation Solution
An in-cell multi-touch display panel system that shares a common transparent conductive layer for both display and touch functions, using a touch display control subsystem to manage gate and source driving lines, and detection electrode layers to enable concurrent display and touch detection operations, thereby optimizing the use of the common voltage and touch-driving layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the image resolution of the display panel is increased, then the display quality is improved, but the display frame rate decreases
Solution Approach 1:
The gate driving lines are divided into N sets, with each set corresponding to one second conductor line. This segmentation allows independent control and timing optimization for different regions of the display panel, enabling high-resolution imaging while maintaining frame rate through parallel processing of different line sets
2Device complexity
If time-sharing is used between display and touch detection operations, then hardware costs are reduced, but the efficiency of concurrent operations decreases
Solution Approach 1:
The system dynamically switches the function of second conductor lines between display common voltage and touch detection driving signals based on timing requirements. During display periods, lines serve as common voltage lines; during touch detection periods, they serve as driving lines. This dynamic reconfiguration enables efficient time-multiplexed operation without dedicated hardware for each function
Solution Approach 2:
The system uses periodic timing intervals to alternately perform display operations and touch detection operations on the same conductor lines. By establishing regular cycles of display frame periods and touch detection periods, the system achieves efficient resource utilization while maintaining both display quality and touch sensing capability
3Device complexity
If a common voltage layer is shared for both display and touch functions, then device complexity is reduced, but signal interference between functions increases
Solution Approach 1:
The system preliminarily configures the common voltage layer with dedicated touch detection driving signal lines that are spatially separated from display signal lines. By pre-arranging the conductor line layout and assigning specific lines for touch detection functions, the system establishes clear signal paths that minimize interference while maintaining layer sharing
Solution Approach 2:
The system introduces timing control signals as intermediaries to coordinate between display and touch detection operations. By using control signals to manage the timing and sequencing of operations on shared conductor lines, the system prevents signal conflicts and interference while enabling efficient resource sharing
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 allows for accurate and efficient multi-touch detection while maintaining high display resolution without the need for time-sharing, reducing hardware costs and improving sensitivity by actively controlling capacitors for reduced parasitic capacitance.
Implementation Method 1
a capacitive touch panel uses a capacitance change generated in an electrostatic combination of the arranged transparent electrodes with the touching part of a human body to generate a current or voltage for detecting the coordinate of the touching part
Implementation Method 2
The self capacitance or the grounded capacitance is not a physical capacitor, but parasitic and stray capacitance on every conductor line
Implementation Method 3
a capacitive touch panel uses a capacitance change generated in an electrostatic combination of the arranged transparent electrodes with the touching part of a human body to generate a current or voltage for detecting the coordinate of the touching part
Data Source
AI summary
An in-cell multi-touch display panel system includes a multi-touch LCD panel and a touch display control subsystem. The multi-touch LCD panel has a TFT layer, a detection electrode layer, and a common-voltage and touch-driving layer. The detection electrode layer has M first conductor lines for performing touch detection by sampling touch detection from the M first conductor lines. The common-voltage and touch-driving layer has N second conductor lines for receiving common voltage in display and touch-driving signal in touch detection. In the detection electrode layer, there are pluralities of detection electrode areas in the intersections of first conductor lines and second conductor lines. Each detection electrode area is connected to a first conductor line by a touch-control transistor. The M×N touch-control transistors are divided in to N sets corresponding to N second conductor lines, respectively.