Display Device Touch Electrode Planarization
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Solution Overview
Problem
Conventional display devices with touch sensors face issues of disconnections and cracks in the touch electrodes due to uneven surfaces and manufacturing processes, which affect the reliability and yield of the devices.
Innovation Solution
A display device structure with a circuit layer, display elements, sealing layer, protective layers, and a touch electrode layer, where the touch electrode layer is arranged on a surface planarized by a protective layer to prevent disconnections and cracks, and connection terminals are exposed through openings in the protective layer for reliable electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the touch electrode layer is arranged directly on the sealing layer, then the manufacturing process is simpler, but disconnections and cracks occur due to surface unevenness
Solution Approach 1:
A protective layer is introduced as an intermediary between the sealing layer and the touch electrode layer. This protective layer serves as a mediator that provides a planarized surface for the touch electrodes, preventing disconnections and cracks while maintaining manufacturing feasibility. The protective layer fills in surface irregularities and creates a uniform foundation for the touch electrode pattern.
Solution Approach 2:
The protective layer is formed in advance before the touch electrode layer is deposited. This preliminary action of planarizing the surface beforehand prevents subsequent connection issues with the touch electrodes, ensuring reliable electrical connections before the actual touch functionality is implemented.
2Shape
If the protective layer covers the connection terminals, then the surface is more uniform, but electrical connections become difficult
Solution Approach 1:
The protective layer is segmented with opening parts that selectively expose the connection terminals. Rather than forming a continuous covering layer, the protective layer is divided into regions, with specific openings created at terminal locations. This segmentation allows the protective layer to provide surface uniformity in most areas while maintaining accessibility for electrical connections at critical points.
Solution Approach 2:
The protective layer has different properties in different regions: it provides complete coverage and planarization in most areas, but has localized openings at connection terminal positions. This local quality variation allows the structure to simultaneously achieve surface uniformity and electrical connectivity where needed.
Data Source
AI summary
A display device includes a circuit layer, a plurality of display elements arranged on the circuit layer, a sealing layer arranged on the plurality of display elements, a protective later arranged on the sealing layer, a touch electrode layer arranged on the protective layer, and a plurality of connection terminals arranged on the circuit layer and an exterior side of the sealing layer. The circuit layer includes a plurality of connection wirings respectively connected to any one the plurality of connection terminals, the protective layer includes a plurality of opening parts respectively in a region overlapping a part of each of the plurality of connection wirings, the touch electrode layer has a plurality of touch electrodes overlapping the display element, and each of the plurality of touch electrodes is connected to any one of the plurality of connection wirings via any one of the plurality of opening parts respectively.