OLED Touch Panel Cathode Integration for Uniform Sensing
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Solution Overview
Problem
The fabrication of OLED touch panels is complex and costly due to the multi-layer touch structure, which increases panel thickness and difficulty in bonding the touch structure with the Touch Integrated Circuit (TIC), and results in non-uniform touch performance as the size of the touch panel grows.
Innovation Solution
A single layer of touch electrodes is arranged using cathodes in a matrix configuration, with spacers and lead parts to connect the cathodes directly with the touch integrated circuit, eliminating blind touch areas and ensuring uniform touch performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-layer touch structure is fabricated on the encapsulation structure, then the touch function is achieved, but the fabrication process complexity and cost increase
Solution Approach 1:
The patent merges the touch electrode layer with the cathode layer into a single integrated structure. The cathode layer serves dual functions as both the electron injection electrode for OLED operation and the touch sensing electrode, eliminating the need for separate touch electrode layers and simplifying the fabrication process while maintaining touch functionality
Solution Approach 2:
The cathode layer is designed to perform multiple functions simultaneously: it acts as the negative electrode for OLED light emission and as the touch sensing electrode for detecting finger contact. This multi-functional design reduces the number of required layers and simplifies the overall device structure
2Reliability
If a multi-layer touch structure is fabricated on the encapsulation structure, then the touch function is achieved, but the panel thickness increases
Solution Approach 1:
By combining the cathode layer and touch electrode layer into one integrated layer, the patent eliminates the thickness contribution of separate touch electrode layers and interlayer materials, thereby reducing the overall panel thickness while preserving complete touch sensing functionality
3Reliability
If a multi-layer touch structure is fabricated on the encapsulation structure, then the touch function is achieved, but the bonding difficulty with TIC increases
Solution Approach 1:
The integration of cathode and touch electrode layers creates a unified structure with fewer interfaces and bonding surfaces. This reduces the number of bonding steps required when assembling the Touch Integrated Circuit (TIC), thereby simplifying the manufacturing process and improving bonding reliability
4Area of stationary object
If the touch panel size grows, then the display area increases, but the touch performance uniformity deteriorates
Solution Approach 1:
The patent implements a grid-shaped electrode pattern where the cathode layer is divided into multiple segmented electrodes arranged in a regular grid. This local segmentation approach ensures uniform charge distribution and consistent capacitive coupling across the entire large-area touch panel, maintaining uniform touch performance regardless of panel size
Data Source
Figure 1~2a
Figure 2b
Figure 3a
AI summary
This disclosure discloses a touch panel, a method for fabricating the same, and a display device. The touch panel includes: a base substrate, a plurality of touch electrode lines, a plurality of cathodes arranged in a matrix, and a plurality of spacers located at gaps between the cathodes on the base substrate, where each cathode corresponds to at least one of the touch electrode lines, and each spacer includes a first photo spacer and a second photo spacer stacked successively on the base substrate; each touch electrode line includes a first lead part and a second lead part, wherein the first lead part is electrically connected with corresponding one of the cathodes, and the second lead part is configured to electrically connect the first lead part with a corresponding pin on a touch integrated circuit; and the first lead part at least covers the surface of the first photo spacer, adjacent to the cathode connected therewith, facing the cathode.