Touch Sensor Electrode Segmentation for Display Thermal Management
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Solution Overview
Problem
The integration of touch sensors into display devices can lead to thermal damage of the display element and reduced detection accuracy due to limited temperature ranges for sensor electrode formation, increased resistivity, and decreased signal-noise ratio, which affects the visibility and detection rate of touch sensors.
Innovation Solution
A display device design incorporating a touch sensor with a first sensor electrode pattern overlapping display pixels and a second sensor electrode pattern in a separation region, connected by an insulating layer, which reduces resistivity and improves detection accuracy by dispersing stress and increasing the surface area for signal detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the touch sensor is integrated into the display device, then the detection accuracy is improved, but thermal damage to the display element occurs due to limited temperature ranges for sensor electrode formation
Solution Approach 1:
The sensor electrode is divided into multiple patterns (first sensor electrode pattern and second sensor electrode pattern) that are spatially separated and connected through conductive layers. This segmentation allows different regions to be formed at different temperatures, with the first pattern formed at lower temperatures to avoid thermal damage to the display element, while the second pattern can be formed at higher temperatures for optimal electrical properties.
Solution Approach 2:
The sensor electrode structure is extended into the vertical dimension with multiple layers (first conductive layer, second conductive layer, third conductive layer) separated by insulating layers. This multi-layer configuration allows the electrode to achieve low resistivity through vertical connectivity while maintaining low-temperature formation processes that protect the display element from thermal damage.
2Measurement precision
If the sensor electrode is formed at higher temperatures to reduce resistivity, then the signal-noise ratio is improved, but the display element suffers thermal damage
Solution Approach 1:
The sensor electrode is segmented into multiple patterns and layers that can be formed at different temperature stages. The first sensor electrode pattern is formed at lower temperatures to protect the display element, while subsequent patterns and conductive layers are added in a sequence that allows progressive temperature increases without exposing the entire structure to high temperatures simultaneously, thereby reducing resistivity while avoiding thermal damage.
Solution Approach 2:
The first sensor electrode pattern is formed preliminarily at low temperatures before the display element is fully assembled or before high-temperature processes are applied. This preliminary formation establishes the basic electrode structure that can later be enhanced with additional conductive layers without requiring the entire structure to withstand high temperatures.
3Reliability
If the sensor electrode pattern is made continuous to improve conductivity, then the resistivity is reduced, but peeling issues occur between the sensor electrode and display element
Solution Approach 1:
Different regions of the sensor electrode structure have different properties: the first sensor electrode pattern in the display region has high conductivity for signal detection, while the second sensor electrode pattern in the separation region provides mechanical separation and stress relief. The insulating layers between conductive layers create local variations in electrical properties that prevent peeling while maintaining overall conductivity through vertical connectivity.
Solution Approach 2:
The sensor electrode is segmented into multiple discrete patterns (first and second patterns) that are connected through conductive layers rather than forming a single continuous structure. This segmentation reduces peeling by distributing stress across multiple connection points and allowing differential thermal expansion between layers, while maintaining conductivity through the vertical conductive pathways.
4Device complexity
If the touch sensor is integrated on the same substrate as the display device, then the device complexity is reduced, but manufacturing precision is compromised due to temperature constraints
Solution Approach 1:
The sensor electrode is segmented into multiple patterns and layers that can be formed using different manufacturing processes at different temperature stages. This segmentation allows each layer to be optimized for its specific formation process, maintaining high manufacturing precision while achieving simple integrated structure. The first pattern can be formed with high precision at low temperatures, followed by addition of subsequent layers.
Solution Approach 2:
The sensor electrode structure is extended into the vertical dimension with multiple conductive layers separated by insulating layers. This multi-layer configuration allows different manufacturing processes to be applied to different layers without interfering with each other, maintaining high manufacturing precision while achieving simple integrated structure. Each layer can be formed and optimized independently before being combined into the final integrated structure.
Data Source
AI summary
A display device includes a display region including a plurality of pixels and a separation region between each of the plurality of pixels and a touch sensor overlapping the display region. The touch sensor includes a sensor electrode and an insulating layer. The sensor electrode includes a first sensor electrode pattern overlapping at least one of the plurality of pixels and a second sensor electrode pattern overlapping at least a part of the separation region. The insulating layer is arranged between the first sensor electrode pattern and the second sensor electrode pattern, and overlaps the first sensor electrode pattern, and covers a first region of the first sensor electrode pattern. The second sensor electrode pattern is arranged on the insulating layer and the first sensor electrode pattern, and connected to a second region of the first sensor electrode pattern.