In-cell Touch Screen Adhesion via Intermediary Layer
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Solution Overview
Problem
The existing self-capacitance touch screen manufacturing process faces issues with weak adhesion between the metal connection line and the planarizing layer due to high temperatures during deposition, leading to defects and quality problems, as well as the risk of short circuits between the metal connection line and pixel electrodes.
Innovation Solution
The self-capacitance in-cell touch screen structure includes a transparent touch control sensing electrode, first and second insulation layers, and a metal connection line formed on a planarizing layer, where the touch control sensing electrode has a greater width and smaller thickness compared to the metal connection line, reducing the impact of gases given off during deposition and preventing short circuits through proper insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the metal connection line is formed on the planarizing layer by deposition process, then the electrical connection is achieved, but the adhesion between metal connection line and planarizing layer becomes weak due to high temperature causing gas emission
Solution Approach 1:
An organic adhesive layer is introduced as an intermediary between the metal connection line and the planarizing layer. This adhesive layer serves as a mediator that maintains strong adhesion even when the planarizing layer emits gases during the deposition process, preventing the metal connection line from detaching while allowing the harmful gas emission to occur without affecting the final adhesion quality.
2Device complexity
If the metal connection line is disposed close to the pixel electrode, then the device complexity is reduced, but the risk of short circuit between metal connection line and pixel electrode increases
Solution Approach 1:
The patent uses multiple insulation layers stacked in the vertical dimension to separate the metal connection line from the pixel electrode. By solving the isolation problem in the vertical dimension rather than increasing horizontal distance, the structure maintains simplicity while effectively preventing short circuits between adjacent conductive elements.
3Reliability
If the touch control sensing electrode is made with greater width and smaller thickness, then the impact of gases during deposition is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The touch control sensing electrode is designed with specific parameter changes: greater width and smaller thickness compared to conventional designs. This parameter optimization reduces the electrode's sensitivity to gas emission during deposition, improving deposition stability. The adhesive layer further compensates for any precision variations by providing strong bonding regardless of minor dimensional variations.
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 enhances adhesion and reduces production costs while improving product quality by minimizing defects and ensuring reliable electrical connections.
Implementation Method 1
the high temperature in the deposition process may cause the planarizing layer 4 to give off gases
Implementation Method 2
an adhesive layer may be disposed between the metal connection line and the planarizing layer
Data Source
AI summary
A self-capacitance in-cell touch screen including a glass array substrate, thin film transistors disposed on the substrate, and pixel electrodes electrically connected with the thin film transistors, a planarizing layer between the pixel electrodes and the thin film transistors. The transparent touch control sensing electrode, a first insulation layer, a second insulation layer, and a metal connection line are disposed on the planarizing layer in sequence. The metal connection line is electrically connected to the touch control sensing electrode through via holes. The first insulation layer is between the planarizing layer and the pixel electrode, and the second insulation layer is located on the pixel electrode. The touch control sensing electrodes are common electrodes to transfer a common voltage and a touch scan signal by time-sharing during a period of displaying one frame image. A method of manufacturing self-capacitance in-cell touch screens and a liquid crystal displays is also disclosed.