In-cell Touch Display Metal Grid Density Optimization
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Solution Overview
Problem
Existing in-cell touch liquid crystal display devices face issues with high parasitic capacitance, reduced detection sensitivity, and increased load due to overlapping electrodes and lead wires, which hinder touch signal detection and light transmittance, especially as panel size and resolution increase.
Innovation Solution
The implementation of a touch layer with metal grid electrodes, where the density of metal grids is higher near the edges and lower at the center, reducing mutual capacitance and resistance, and utilizing a color filter substrate with a black matrix layer to shield electrodes, thereby optimizing the touch structure for improved sensitivity and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the panel size and resolution are increased, then the display quality is improved, but the parasitic capacitance increases and detection sensitivity decreases
Solution Approach 1:
The patent applies different metal grid densities in different regions of the touch panel. The edge regions have higher metal grid density while the center region has lower density. This local differentiation optimizes the balance between detection sensitivity at edges and parasitic capacitance reduction in the center, resolving the contradiction between maintaining high detection sensitivity and reducing parasitic capacitance in large high-resolution panels.
2Measurement precision
If the metal grid density is increased, then the detection sensitivity is improved, but the resistance and energy consumption increase
Solution Approach 1:
The patent implements variable metal grid density across different regions. Edge regions with higher detection requirements have denser metal grids for improved sensitivity, while the center region has sparser metal grids to reduce resistance and energy consumption. This spatially differentiated approach resolves the contradiction between detection sensitivity and energy efficiency.
3Device complexity
If the electrodes and lead wires overlap, then the in-cell touch structure is achieved, but the parasitic capacitance increases and light transmittance decreases
Solution Approach 1:
The patent uses different metal grid densities in different regions to manage parasitic capacitance. The lower density in the center region reduces parasitic capacitance effects, while the edge regions maintain higher density for detection sensitivity. This resolves the contradiction between achieving integrated in-cell structure and minimizing parasitic capacitance.
Solution Approach 2:
The black matrix layer serves as an intermediary shielding structure between the metal grid electrodes and the liquid crystal display layers. This intermediary layer reduces parasitic capacitance coupling while allowing light to pass through, resolving the contradiction between integrated structure benefits and parasitic capacitance reduction.
4Measurement precision
If the metal grid density is increased, then the detection sensitivity is improved, but the light transmittance decreases
Solution Approach 1:
The patent implements higher metal grid density at the edges where detection sensitivity is more critical, and lower density in the center region where light transmittance is more important. This spatial differentiation resolves the contradiction between detection sensitivity and light transmittance by optimizing metal distribution according to regional requirements.
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 decreases parasitic capacitance, enhances detection sensitivity, and reduces energy consumption while maintaining light transmittance, effectively addressing the limitations of existing in-cell touch display devices.
Implementation Method 1
utilizing a color filter substrate with a black matrix layer to shield electrodes
Data Source
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AI summary
An in-cell touch display device is disclosed. The device includes a color filter substrate, a Thin Film Transistor array substrate, and a liquid crystal layer disposed between the color filter substrate and the Thin Film Transistor array substrate. The color filter substrate includes a grid black matrix layer, a touch layer, and a color filter layer, where the touch layer includes a plurality of metal grid electrodes. In addition, each electrode is aligned with the grid of the black matrix layer in a light transmission direction, and a density of the metal grid electrodes adjacent to the edge of the metal grid electrodes is greater than a density of the metal grid electrodes adjacent to the center of metal grid electrodes.