Shielding Electrode Design for Touch Display Electric Field Leakage
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Solution Overview
Problem
Touch-detection display devices face challenges in maintaining display quality due to the degradation caused by the interaction between drive electrodes and detection electrodes, which affects the alignment of liquid crystals and leads to non-uniformity in display.
Innovation Solution
The configuration of common electrodes and metallic wiring lines, with specific gap arrangements and contact holes, ensures that the electric field is shielded, reducing leakage and alignment errors, and allows for flexible positioning of gaps between electrodes to minimize display non-uniformity and color mixture issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If drive electrodes and detection electrodes are arranged closely for touch detection function, then touch detection capability is improved, but display quality degrades due to electric field interaction and liquid crystal alignment errors
Solution Approach 1:
A shielding electrode is introduced as an intermediary component between the drive electrode and detection electrode. This shielding electrode acts as a mediator that blocks the electric field interaction between the drive and detection electrodes, preventing liquid crystal alignment errors while maintaining touch detection functionality. The shielding electrode is connected to a fixed potential (ground or reference potential) to effectively suppress electric field leakage.
Solution Approach 2:
The electrode structure is segmented into three distinct components: drive electrode, shielding electrode, and detection electrode. By dividing the originally direct two-electrode configuration into three segmented layers, the electric field paths are separated and controlled, allowing touch detection to function while preventing display quality degradation from electric field interference.
2Device complexity
If signal lines are arranged parallel to drive electrodes to simplify wiring, then device complexity is reduced, but electric field leakage increases causing display non-uniformity
Solution Approach 1:
The shielding electrode serves as an intermediary barrier that blocks electric field leakage from the drive electrode and signal lines into the display area. Even when signal lines run parallel to drive electrodes, the shielding electrode prevents their electric fields from interfering with the liquid crystal alignment, maintaining display uniformity while allowing simplified wiring arrangements.
Solution Approach 2:
The potential harmful electric field leakage from parallel signal lines and drive electrodes is converted into a controlled phenomenon. The shielding electrode captures and redirects the electric field lines, preventing them from reaching the liquid crystal layer. This transforms what would be a harmful interference into a contained electric field pattern that does not affect display quality.
3Manufacturing precision
If gaps between common electrodes are minimized to reduce color mixture, then display quality is improved, but electric field leakage increases causing alignment errors
Solution Approach 1:
The shielding electrode is positioned between the drive electrode and the liquid crystal layer, acting as an intermediary that blocks electric field leakage regardless of the gap size between common electrodes. This allows the gaps to be minimized for color accuracy while the shielding electrode simultaneously prevents electric field leakage that would cause alignment errors.
Solution Approach 2:
The solution moves from a two-dimensional planar arrangement of electrodes to a three-dimensional layered structure with the shielding electrode inserted between layers. This dimensional change allows the gaps between common electrodes to be small for color accuracy while the shielding electrode in the intermediate layer blocks electric field leakage paths vertically, resolving the contradiction between gap size and field leakage.
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 suppresses display quality degradation by reducing electric field leakage and enabling flexible gap positioning, thereby improving display uniformity and reducing color mixture and shift issues.
Implementation Method 1
a metallic wiring line provided on the first interlayer insulating film to overlap the signal line
Implementation Method 2
parasitic capacitance between the signal line and the common electrode
Data Source
AI summary
According to one embodiment, a display device includes a first signal line covered by a first interlayer insulating film, a first metallic wiring line provided on the first interlayer insulating film to overlap the first signal line, a pixel electrode next to the first metallic wiring line, a second interlayer insulating film covers the first metallic wiring line and the pixel electrode, and first and second common electrodes provided on the second interlayer insulating film, a gap between the first common electrode and the second common electrode, which overlap the first signal line and the first metallic wiring line, and the first metallic wiring line being connected to the first common electrode in a non-display area.