In-Cell AMOLED Touch Panel Electrode Integration
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Solution Overview
Problem
The existing manufacturing process of touch panel LCD devices, where the touch panel and LCD device are assembled separately, results in increased thickness, complexity, and cost, and the use of Indium Tin Oxide (ITO) layers complicates the process and increases thickness, hindering the trend of lightweight and thin displays.
Innovation Solution
An in-cell touch panel liquid crystal display device integrates the touch panel function between two substrates, using a common electrode layer with first and second common electrodes arranged in a matrix to detect touch positions, eliminating the need for a separate touch panel assembly and reducing thickness through time division multiplexing or simultaneous signal provision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the touch panel and LCD device are assembled separately, then the touch panel can be independently manufactured and tested, but the overall device thickness increases and manufacturing complexity increases
Solution Approach 1:
The patent combines the touch panel electrode layer with the LCD common electrode layer into a single integrated structure. The touch sensing electrodes and LCD common electrode are formed simultaneously in the same manufacturing process, eliminating the need for separate assembly and reducing overall device thickness while maintaining independent functionality of both touch sensing and display operations
2Object-affected harmful factors
If a transparent electrode shielding layer (ITO layer) is added to reduce noise interference, then the touch panel noise resistance improves, but the manufacturing complexity and device thickness increase
Solution Approach 1:
The shielding layer is integrated into the same electrode layer that serves both as the LCD common electrode and the touch sensing electrode. This multi-functional electrode structure provides noise shielding capability while maintaining touch sensitivity and eliminating the need for additional separate shielding layers, thereby reducing manufacturing complexity and device thickness
Solution Approach 2:
The common electrode layer is designed to perform multiple functions simultaneously: it serves as the LCD common electrode for display operation, as the touch sensing electrode for touch detection, and as a shielding layer for noise reduction. This multi-functionality eliminates the need for separate dedicated shielding layers
3Device complexity
If the common electrode layer is used for both display and touch detection simultaneously, then the device structure is simplified, but signal interference between display and touch signals may occur
Solution Approach 1:
The patent implements time-division multiplexing where the common electrode alternates between display mode and touch detection mode in periodic time slots. During display periods, the electrode functions as LCD common electrode; during touch detection periods, it functions as touch sensing electrode. This periodic switching eliminates signal interference while maintaining structural simplicity
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 integration simplifies the manufacturing process, reduces the device thickness, and improves touch sensing accuracy and imaging quality without compromising display functionality.
Implementation Method 1
The transmittance of the liquid crystals varies with the voltage applied to the liquid crystals, in order for displaying with different gray scales
Implementation Method 2
the first common electrodes and the second common electrodes are configured to detect a touched position on the in-cell touch panel liquid crystal display device
Data Source
AI summary
An AMOLED panel is provided. A cathode of the AMOLED panel is patterned into rows of first electrodes and columns of second electrodes, two adjacent first electrodes in the same row are electrically connected with each other, and two adjacent second electrodes in the same column are electrically connected to a conductive line in a different layer via plugs. The rows receive driving signals sequentially and the columns generate sensing signals for detecting proximity of an external conductive object.