In-Cell Touch LCD Flip Structure and Common Electrode Integration
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Solution Overview
Problem
In-cell touch liquid crystal display devices face issues with increased weight and thickness, reduced light penetration, and decreased touch sensitivity due to the separate coating of transparent high-resistance conductive layers, which require additional etching and cleansing processes and degrade anti-static properties.
Innovation Solution
The design features a flip structure where the TFT array substrate with a larger area is positioned on top of the CF array substrate, with a nitride insulating layer blocking metal color production and a common electrode formed on the upper substrate to enhance touch sensitivity and electrostatic performance, eliminating the need for a high-resistance conductive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a transparent high-resistance conductive layer is separately coated on the color filter substrate to enable touch function, then touch sensitivity is improved, but weight increases, thickness increases, and light penetration ratio decreases
Solution Approach 1:
The patent merges the touch sensor function with the color filter substrate by forming the common electrode and touch electrode directly on the color filter substrate, eliminating the need for a separate transparent conductive layer. This integration maintains touch sensitivity while reducing weight and thickness by consolidating multiple functional layers into one substrate.
Solution Approach 2:
The color filter substrate is given multiple functions: it serves as both the color filter layer and the base for the touch sensor electrodes. The common electrode and touch electrode are formed on the same substrate that provides color filtering, making the substrate universal and eliminating the need for additional separate layers for touch functionality.
2Ease of operation
If a transparent high-resistance conductive layer is separately coated to enable touch function, then touch sensitivity is improved, but device thickness increases
Solution Approach 1:
The patent combines the touch sensor structure with the color filter substrate by forming electrodes directly on it, eliminating the need for separate transparent conductive layers and reducing overall device thickness. The integration of touch functionality into the existing substrate structure avoids adding extra thickness.
3Ease of operation
If a transparent high-resistance conductive layer is separately coated, then touch function is enabled, but light penetration ratio decreases and reflectance increases
Solution Approach 1:
The patent integrates the touch electrode directly on the color filter substrate, eliminating the need for a separate transparent conductive layer. This removal of intermediate layers improves light penetration ratio and reduces reflectance while maintaining touch sensitivity, as fewer layers mean less light interference.
4Ease of operation
If a transparent high-resistance conductive layer is separately coated, then touch function is enabled, but additional etching and cleansing processes are required, increasing fabrication complexity
Solution Approach 1:
The patent combines the formation of touch electrodes with the existing TFT fabrication process by forming the common electrode and touch electrode on the color filter substrate using the same manufacturing steps. This integration eliminates additional etching and cleansing processes that would be required for separate transparent conductive layer coating, reducing fabrication complexity.
5Ease of operation
If a transparent high-resistance conductive layer is used, then touch function is enabled, but anti-static properties are degraded
Solution Approach 1:
The patent changes the electrical parameter of the conductive layer by using a transparent conductive oxide material with appropriate conductivity characteristics that provides both touch sensitivity and anti-static properties. The common electrode and touch electrode are formed with specific conductivity parameters that balance touch function and electrostatic protection, improving reliability.
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 reduces fabrication complexity, enhances touch sensitivity by increasing finger capacitance and common electrode area, and improves display properties by reducing resistance and light reflection.
Implementation Method 1
a nitride insulating layer blocking metal color production
Implementation Method 2
enhance touch sensitivity by increasing finger capacitance and common electrode area
Implementation Method 3
a common electrode formed on the upper substrate to enhance touch sensitivity and electrostatic performance
Implementation Method 4
liquid crystal layer interposed between the upper array substrate and the lower array substrate
Data Source
AI summary
An in-cell touch LCD in one example includes a lower array substrate; an upper array substrate having an area greater than the lower array substrate; gate and data lines and a thin film transistor on the inner surface of the upper array substrate; a planarization layer on the inner surface of the upper array substrate, and exposing a part of a drain electrode; a common electrode on the planarization layer; a passivation layer on the planarization layer and exposing the part of the drain electrode; a touch line on the passivation layer; an inter-layered insulating layer on the passivation layer, covering the touch line, and exposing the part of the drain electrode, the touch line and the common electrode; a plurality of pixel electrodes on the inter-layered insulating layer, overlapping the common electrode, and connected to the drain electrode; and a connection line connecting the touch line and the pixel electrodes.