Foldable Touch Substrate Layout to Prevent Bending-Area Cracks
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Solution Overview
Problem
In foldable display apparatuses using the FMLOC technique, the inorganic layer between metal traces cracks when bent at large angles, leading to peeling and affecting the product's service life.
Innovation Solution
The touch substrate design includes touch signal lines with a first and second sub-line configuration, where the orthographic projection of the first sub-line is located within the projection of the second sub-line in the bending area, and a first insulating layer with via holes to prevent cracks, ensuring the substrate can withstand larger bends without damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a double-layer metal trace with inorganic layer is used in foldable products, then the trace structure provides good electrical connection, but the inorganic layer cracks when bent at large angles leading to peeling and reduced service life
Solution Approach 1:
The patent removes the inorganic layer from the trace structure in the bending area, extracting the problematic component that causes cracking during large-angle bending while retaining the metal trace structure for electrical connection
Solution Approach 2:
The patent applies different structural configurations to different areas: in the bending area, only metal traces are used without inorganic layer, while in non-bending areas, the complete multi-layer structure with inorganic layer is maintained, optimizing both flexibility and electrical performance
2Reliability
If the inorganic layer is disposed between two layers of metal traces, then the trace structure is complete, but the inorganic layer peels off when bent at large angles affecting product durability
Solution Approach 1:
The inorganic layer is extracted or removed from the trace structure in the bending area to eliminate the peeling problem that occurs during large-angle bending, while maintaining the metal trace structure for electrical functionality
3Weight of moving object
If touch signal lines are directly manufactured on light-emitting structure layer and encapsulation layer, then the product becomes lighter and thinner, but the inorganic layer cracks during bending affecting service life
Solution Approach 1:
The patent implements local structural optimization where the trace configuration differs between bending and non-bending areas, allowing the FMLOC lightweight structure to be maintained while preventing cracks in critical bending regions through modified trace design
Data Source
AI summary
The present disclosure provides a touch substrate and a display apparatus. The touch substrate provided in embodiments of the present disclosure comprises a base and a plurality of touch signal lines. The base comprises a bending area and a non-bending area located beyond the bending area. The bending area extends in a first direction. The plurality of touch signal lines are located on one side of the base. At least some of the touch signal lines extend to the bending area. Each of the plurality of touch signal lines comprises: a first sub-touch signal line and a second sub-touch signal line on the side of the first sub-trace line away from the base. In the bending area, the orthographic projection of the first sub-touch signal line on the base falls within the orthographic projection of the second sub-touch signal line on the base.