Foldable Display Panel Fan-Out Layout for Lower Parasitic Capacitance
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Solution Overview
Problem
Existing display technologies face challenges in efficiently accommodating the bending and folding requirements of flexible display panels, particularly in ensuring uniform trace distribution and reducing parasitic capacitance to enhance flexibility and reliability.
Innovation Solution
The display panel design includes asymmetrically arranged trace groups with varying trace lengths and configurations, such as curved and widened portions, along with staggered trace and connection line arrangements in multiple layers to optimize flexibility and reduce parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fan-out traces are arranged in a conventional symmetric pattern, then manufacturing is simplified, but parasitic capacitance increases and flexibility is reduced
Solution Approach 1:
The patent applies asymmetry by dividing fan-out traces into two groups with different configurations: a first group with traces extending in a first direction and a second group with traces extending in a second direction. This asymmetric arrangement reduces parasitic capacitance between adjacent traces while maintaining manufacturing feasibility, directly resolving the contradiction between reliability (flexibility) and device complexity (trace arrangement).
Solution Approach 2:
The patent segments the fan-out traces into multiple groups (first trace group and second trace group) with different orientations and configurations. Each group is further divided into multiple sub-groups, creating a hierarchical segmentation that reduces overall parasitic capacitance while distributing the complexity across manageable segments, thus improving flexibility without overwhelming manufacturing complexity.
2Reliability
If trace length is increased to reduce resistance, then signal transmission improves, but parasitic capacitance increases
Solution Approach 1:
The patent uses asymmetric trace arrangement where traces in different groups have different lengths and orientations. This allows certain traces to be longer (reducing resistance) while others are shorter (reducing capacitance), optimizing the trade-off between signal transmission quality and parasitic capacitance through differential design.
Solution Approach 2:
The patent transitions from a single-direction trace layout to a multi-dimensional arrangement with traces extending in different directions (first direction and second direction). This dimensional diversification allows traces to achieve adequate length for low resistance while maintaining larger spacing in certain directions, thereby reducing parasitic capacitance.
3Area of stationary object
If trace spacing is reduced to increase density, then area utilization improves, but parasitic capacitance increases
Solution Approach 1:
The patent implements asymmetric spacing where traces in the first group have different spacing from traces in the second group. This allows dense packing in certain regions (improving area utilization) while maintaining larger spacing in critical regions where parasitic capacitance would be problematic, achieving both goals simultaneously.
Solution Approach 2:
By segmenting traces into multiple groups and sub-groups with different spacing configurations, the patent creates zones of high density and zones of low density. This segmented approach allows overall high area utilization while local spacing variations prevent excessive parasitic capacitance accumulation.
4Ease of manufacture
If conventional trace layout is used, then manufacturing is easier, but bending reliability is reduced
Solution Approach 1:
The asymmetric trace arrangement with two groups extending in different directions creates inherent mechanical flexibility that accommodates bending stresses better than conventional symmetric layouts. While slightly more complex than conventional designs, the asymmetry provides stress distribution benefits that improve bending reliability without significantly complicating manufacturing.
Solution Approach 2:
The patent applies different trace configurations (different lengths, orientations, and spacing) to different local regions of the display panel. This local quality optimization ensures that traces in bending-prone areas have configurations specifically suited for flexibility, while traces in stable areas can be optimized for electrical performance, thus improving overall bending reliability without uniformly increasing manufacturing complexity.
Data Source
AI summary
A display panel includes a display area, a first fan-out region, a bending region and fan-out traces disposed in the first fan-out region. The fan-out trace includes a lead-out segment and an extension segment that are connected. The fan-out traces include a first trace group and a second trace group that are not symmetrically. The first trace group includes first trace bundles. A first trace bundle closest to the second trace group includes a first sub-bundle and a second sub-bundle, each of which includes a lead-out portion and an extension portion that are connected. The lead-out portion and the extension portion are constituted by lead-out segments and extension segments of fan-out traces in a corresponding sub-bundle, respectively. A distance between the extension portion of the first sub-bundle and the extension portion of the second sub-bundle is greater than a distance between two adjacent fan-out traces in any first trace bundle.