In-Cell Touch Display Panel Voltage Uniformity
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Solution Overview
Problem
In in-cell touch screens, the common voltage applied to touch electrodes is not uniformly distributed due to resistance differences, leading to luminance imbalances and non-uniform voltage application, affecting display quality.
Innovation Solution
A display panel design that includes multiple signal lines for supplying common voltage to touch electrodes, featuring a first signal line connected to the touch electrode, a plurality of dummy lines, and a switching transistor to distribute the common voltage via a second signal line, which is activated by a VCOM enable signal, ensuring uniform voltage distribution across the touch electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single common voltage electrode line is provided for each touch block, then the structure is simple and the driving IC voltage supply channel is within limits, but resistance differences cause non-uniform voltage application and luminance imbalance
Solution Approach 1:
The single common voltage electrode line is segmented into multiple signal lines (first signal line and second signal line) that are distributed across different regions of the touch electrode. This segmentation reduces the resistance of each individual line and ensures more uniform voltage distribution across the touch electrode, eliminating luminance imbalance while maintaining structural simplicity.
Solution Approach 2:
Different signal lines are assigned to different regional areas of the touch electrode based on their resistance characteristics. The first signal line serves a first regional area while the second signal line serves a second regional area, allowing each line to be optimized for its specific region and achieving overall voltage uniformity.
2Manufacturing precision
If multiple signal lines are provided to supply common voltage, then voltage uniformity is improved, but the device complexity increases
Solution Approach 1:
The dummy line is given multi-functionality: it serves as both a structural placeholder during manufacturing and as an active second signal line for voltage supply during operation. By configuring the dummy line as a functional signal line with a switching transistor, the patent eliminates the need for separate dedicated signal lines while achieving uniform voltage distribution.
Solution Approach 2:
The switching transistor dynamically controls the activation of the second signal line based on the VCOM enable signal. During display operation, the switching transistor activates the second signal line to provide common voltage; during touch sensing operation, it deactivates the second signal line. This dynamic control allows the system to adapt its complexity based on operational mode.
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 configuration effectively alleviates common voltage imbalances, enhancing luminance uniformity and image quality by allowing the common voltage to be propagated in multiple directions, reducing luminance differences between pixels.
Implementation Method 1
a switching transistor provided to supply the common voltage to a second signal line by being switched by an applied VCOM enable signal
Data Source
AI summary
A display panel and a manufacturing method thereof are proposed. A display panel may include: a touch electrode provided to supply a common voltage through an electrode; a first signal line connected to the touch electrode and provided to supply the common voltage applied by a driving IC to the touch electrode; a plurality of dummy lines provided to be connected to the touch electrode; and a switching transistor provided to supply the common voltage to a second signal line by being switched by an applied VCOM enable signal, wherein the second signal line is configured to supply the common voltage to the touch electrode.