Bilateral Touch Electrodes Reduce TFT Interference
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Solution Overview
Problem
Conventional capacitive touch panel structures face challenges such as complex manufacturing processes, fragility, signal interference, and increased thickness, particularly in in-cell and on-cell structures, which affect reliability and touch signal accuracy.
Innovation Solution
A touch unit is designed with a substrate, black matrix, first direction sensing electrode, and second direction sensing electrode, where the first direction sensing electrode is metallic and disposed on the black matrix, and the second direction sensing electrode is transparent conductive, positioned on opposite sides of the substrate, eliminating the need for a bridge insulation layer and allowing for different materials for X-axis and Y-axis sensors, thereby reducing thickness and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If in-cell or on-cell structure is used to reduce thickness, then the touch panel becomes thinner, but TFT layer interference increases and manufacturing complexity increases
Solution Approach 1:
The patent segments the sensing electrodes into two separate directions (X-axis and Y-axis) positioned on opposite sides of the substrate. This segmentation allows each electrode to be optimized independently and reduces interference from the TFT layer by distributing the sensing function across multiple components rather than having all sensing elements in one location close to the TFT layer.
Solution Approach 2:
The patent transitions from a single-layer sensing structure to a multi-layer structure with electrodes on both sides of the substrate. By adding the dimension of bilateral electrode placement, the system achieves better signal quality and reduced interference while maintaining thin overall thickness.
2Strength
If G/G structure with cover lens is used, then hardness and low signal interference are achieved, but manufacturing complexity and thickness increase
Solution Approach 1:
The patent extracts the sensing function from the traditional G/G structure with cover lens and integrates it directly into the substrate with electrodes on both sides. This extraction eliminates the need for a separate cover lens while maintaining the sensing capability, thereby reducing manufacturing complexity and thickness.
Solution Approach 2:
The substrate serves multiple functions: it acts as both the structural base and the mounting platform for sensing electrodes on both sides. This multi-functionality eliminates the need for separate cover lens and sensing layer, simplifying the overall structure and manufacturing process.
3Ease of manufacture
If OGS structure with strengthened glass is used, then manufacturing is simplified, but the substrate becomes more fragile and reliability decreases
Solution Approach 1:
The patent applies different material properties to different locations: the substrate maintains its base material properties while the bilateral electrode structure provides localized reinforcement and signal sensing capability. This local quality approach allows the substrate to be thinner without compromising overall structural reliability.
4Adaptability or versatility
If touch sensing unit is placed closer to TFT layer in in-cell structure, then integration is improved, but TFT layer interference over the circuit increases
Solution Approach 1:
The patent segments the sensing function into two separate directional electrodes on opposite sides of the substrate. This segmentation physically separates the sensing elements from the TFT layer, reducing electrical interference while maintaining integration benefits through the bilateral configuration.
Solution Approach 2:
The substrate acts as an intermediary layer between the sensing electrodes and the TFT layer. By positioning electrodes on both sides of the substrate, the patent creates a physical buffer that reduces direct interference from the TFT layer while maintaining effective touch sensing capability.
Data Source
AI summary
In a flat panel display, two direction sensing electrodes, respectively representing an X-axis sensor and a Y-axis sensor, are disposed on both sides of a substrate of a color filter of the flat panel display. One direction sensing electrode is disposed in the black matrix on one side of the substrate and the other direction sensing electrode is disposed on the other side of the substrate locating farther from the black matrix. The configuration provides a much thinner dimension for the flat panel display with touch function while the touch function is less interfered by the display panel.