Shield Layer for Leakage Field in In-Cell Touch Displays
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Solution Overview
Problem
In liquid crystal display devices with in-cell touch panels, the leakage electric field from signal lines affects adjacent pixels due to the positioning of the common electrode, leading to suboptimal display and visibility issues, especially when assembly deviations occur between substrates.
Innovation Solution
A shield layer is introduced on the signal wiring layer to prevent leakage electric fields from affecting the liquid crystal layer, with the common electrode layers arranged to cover and intersect the signal wiring layers, and wiring auxiliary layers used to reduce resistance and prevent color mixture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the common electrode is divided into multiple areas positioned on signal lines, then the in-cell touch panel function is enabled, but leakage electric fields from signal lines affect adjacent pixels causing display defects
Solution Approach 1:
A shield layer is introduced as an intermediary component between the signal line and the liquid crystal layer. This shield layer acts as a mediator that blocks the harmful leakage electric field from the signal line, preventing it from affecting the liquid crystal layer while allowing the common electrode to maintain its divided structure for touch panel functionality.
Solution Approach 2:
The harmful leakage electric field effect is extracted and isolated from the main system by positioning the shield layer specifically at the problematic interface between signal lines and liquid crystal. This separates the touch panel function from the harmful electromagnetic interference, allowing both to coexist without mutual degradation.
2Ease of manufacture
If assembly deviation occurs between counter substrate and array substrate, then manufacturing variability increases, but the divided common electrode appears as lines causing visible display defects
Solution Approach 1:
The shield layer serves as a compensating intermediary that masks the visual impact of assembly deviations. By positioning the shield layer to cover the divided common electrode areas, it prevents the formation of visible lines even when assembly deviation occurs, thereby maintaining display quality despite manufacturing variability.
Solution Approach 2:
The shield layer is designed in advance to compensate for potential assembly deviations. By pre-positioning the shield layer to cover the vulnerable areas where lines might appear, the design cushions against the harmful effects of assembly variability before they can manifest as visible defects.
3Object-affected harmful factors
If the common electrode covers the signal wiring layer, then shielding effect is improved, but resistance of the common electrode increases
Solution Approach 1:
The common electrode is divided into multiple separate areas rather than forming a continuous layer. This segmentation reduces the total resistance by allowing current to flow through multiple parallel paths while still maintaining the shielding effect, as each divided area independently blocks leakage electric fields from signal lines.
Solution Approach 2:
The problem is solved by transitioning from a two-dimensional continuous electrode layer to a multi-area configuration that utilizes the third dimension (vertical layering). The divided common electrode areas are positioned at different locations to cover signal lines while maintaining low resistance through distributed configuration.
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 shields the leakage electric field, ensuring desired display quality and preventing the appearance of lines in the display, while also reducing color mixture and enhancing the common electrode's resistance in high-definition panels.
Implementation Method 1
a leakage electric field from the signal line has an effect on the liquid crystal layer through the divided area of the common electrode
Implementation Method 2
a liquid crystal layer arranged between the array substrate and the counter substrate
Data Source
AI summary
If a divided area of common electrode layers is positioned on a source line, a leakage electric field on the source line has an effect on a liquid crystal layer through the divided area of the common electrode layers. A display device includes an array substrate and a counter substrate. The array substrate includes scanning signal wiring layers, video signal wiring layers, pixel electrode layers arranged in a layer higher than the video signal wiring layers, and common electrode layers arranged in a layer higher than the pixel electrode layers. The common electrode layers are arranged in positions covering the video signal wiring layers in a plan view. The common electrode layers are divided in the extending direction of the video signal line.