In-Cell Touch Array Substrate Shielding TFT Noise
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Solution Overview
Problem
In-cell touch panels face display and touch defects due to noise interference from thin film transistor (TFT) circuits caused by gaps in common electrodes, which are typically made of indium tin oxide (ITO) and serve both as capacitor electrodes and touch sensors.
Innovation Solution
The array substrate design incorporates three transparent conductive layers: a first layer covering the transistor layer, a second layer with a pattern of touch electrodes, and a third layer with a pattern of pixel electrodes, where the touch electrodes serve as the common electrode during display and the first layer acts as a shielding layer during touch operations, reducing interference by overlapping to form storage capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the common electrode is divided into block-like or bar-like portions to adapt to the touch sensing circuit layout, then the touch sensing function can be implemented, but the gaps between divided portions cause increased noise interference from TFT circuits to the liquid crystal layer and touch electrode
Solution Approach 1:
The patent divides the common electrode into multiple transparent conductive layers (first transparent conductive layer, second transparent conductive layer with touch electrode pattern, third transparent conductive layer with pixel electrode pattern) that can be independently controlled. This segmentation allows different portions to serve different functions: the first layer provides continuous shielding, while the second and third layers enable touch sensing and display functions respectively.
Solution Approach 2:
The patent implements dynamic control by applying different voltages to different transparent conductive layers at different time stages. During display stage, common voltage is applied to all layers for shielding. During touch stage, touch voltage signals are applied to the second layer while the first layer maintains shielding function. This dynamic voltage control optimizes both shielding effectiveness and touch sensing performance.
2Object-affected harmful factors
If the common electrode is formed as an entire layer for shielding, then electric field shielding is effective, but it cannot accommodate the layout requirements of touch sensing circuits
Solution Approach 1:
The common electrode is segmented into multiple transparent conductive layers with different patterns and functions. The first transparent conductive layer maintains continuity for shielding, while the second and third layers are patterned to accommodate touch sensing circuits and pixel electrodes respectively.
Solution Approach 2:
Each transparent conductive layer serves multiple functions: the first layer provides both shielding and forms storage capacitors with the pixel electrode; the second layer serves as both common electrode and touch sensing electrode; the third layer provides pixel electrode function. This multi-functionality resolves the contradiction between shielding and circuit adaptation.
3Adaptability or versatility
If multiple transparent conductive layers are added to enable both shielding and touch function, then both functions can be achieved, but the device structure becomes more complex
Solution Approach 1:
The patent merges the common electrode and touch sensing electrode functions into the second transparent conductive layer, and combines shielding and storage capacitor functions in the first transparent conductive layer. This merging reduces the total number of separate components while achieving multiple functions.
Solution Approach 2:
Each transparent conductive layer is designed to perform multiple functions: the first layer provides both shielding and storage capacitance; the second layer serves as common electrode, touch sensing electrode, and forms storage capacitors; the third layer provides pixel electrode function. This multi-functionality approach achieves dual functionality without proportionally increasing structural complexity.
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 electric fields, reducing display and touch defects, thereby improving the yield and performance of in-cell touch panels by minimizing interference from TFT circuits.
Implementation Method 1
the first transparent conductive layer covers the transistor layer at a display area... the first transparent conductive layer acts as a shielding layer during touch operations, reducing interference
Implementation Method 2
the pixel electrode overlaps the first transparent conductive layer to form a first storage capacitor at the pixel area
Implementation Method 3
the pixel electrode overlaps the touch electrode to form a second storage capacitor at the pixel area
Data Source
AI summary
The present disclosure provides an array substrate, its driving method and manufacturing method, and a display device. The array substrate includes a transistor layer arranged on a base, and a first transparent conductive layer, a first insulation layer, a second transparent conductive layer, a second insulation layer and a third transparent conductive layer sequentially arranged on the transistor layer. The first transparent conductive layer covers the transistor layer at a display area, the second transparent conductive layer includes a pattern of touch electrodes, and the third transparent conductive layer includes a pattern of pixel electrodes. Within any pixel area of the display area, the pixel electrode is connected to a pixel electrode connection end of the transistor layer through a via-hole in the first insulation layer and the second insulation layer, and the first transparent conductive layer is provided with an opening at a position corresponding to the via-hole.