Foldable Display Cover Assembly for Stress-Balanced Durability
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Solution Overview
Problem
The challenges of improving the lifespan and reliability of foldable display devices, particularly in terms of structural design and material selection, have not been adequately addressed in existing technologies.
Innovation Solution
A foldable display device design incorporating a display panel with a cover structure composed of multiple layers, including an inner and outer substrate with adhesives, where the distance between the edge of the first adhesive and the inner substrate is greater than zero, and specific thickness and modulus ratios are maintained to enhance stress balance and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a foldable display device uses a simple cover structure, then the device complexity is reduced, but the reliability and lifespan during folding are worsened
Solution Approach 1:
The cover structure is divided into multiple independent layers: inner substrate layer, first adhesive layer, outer substrate layer, second adhesive layer, and display panel layer. Each layer performs a specific function, allowing the complex folding protection task to be distributed across multiple simpler components rather than requiring a single complex structure.
Solution Approach 2:
The cover structure employs composite material design by combining different materials with complementary properties: the inner substrate provides flexibility and stress absorption, the outer substrate provides rigidity and external force resistance, and the adhesive layers provide bonding and stress distribution. This composite approach enhances overall folding reliability without requiring excessive complexity in any single component.
2Reliability
If the cover structure uses thicker adhesive layers for better bonding, then the reliability improves, but the device thickness and flexibility are worsened
Solution Approach 1:
The patent optimizes the thickness parameter of adhesive layers to achieve the best balance between bonding reliability and device flexibility. Rather than using uniformly thick adhesive layers, the design specifies precise thickness ranges that provide sufficient bonding strength while maintaining the overall flexibility needed for folding operations.
Solution Approach 2:
The adhesive layers are strategically positioned and sized to provide bonding exactly where needed at the interfaces between components. This localized bonding approach ensures reliable connections at critical joints while minimizing adhesive thickness in areas where flexibility is prioritized, thus resolving the contradiction between bonding reliability and device thinness.
3Reliability
If the cover structure provides stronger protection against external forces, then the reliability improves, but the stress balance during folding is worsened
Solution Approach 1:
The inner substrate layer acts as a counterbalancing element that provides flexibility and stress absorption to offset the rigidity of the outer substrate layer. This creates a stress balance system where the flexible inner layer compensates for the protective but potentially stress-concentrating outer layer, maintaining overall stress equilibrium during folding while still providing external force protection.
Solution Approach 2:
The composite structure combines materials with different mechanical properties: the outer substrate provides rigidity for external force resistance, while the inner substrate provides flexibility for stress distribution. The adhesive layers bond these contrasting materials, creating a unified structure that achieves both protection and stress balance simultaneously through material complementarity.
4Illumination intensity
If the display layer uses self-emissive elements for better display effect, then the display quality improves, but the device complexity and manufacturing difficulty are worsened
Solution Approach 1:
The display layer is merged with the flexible substrate to form an integrated assembly, reducing the number of separate components. The self-emissive display elements are directly incorporated into the flexible substrate structure, combining the display function with the flexible support structure and simplifying the overall device architecture while maintaining high display quality.
Data Source
AI summary
A display device is provided by the present disclosure and includes a display panel, a cover, and a second adhesive. The cover includes an inner substrate, an outer substrate, and a first adhesive disposed between the inner substrate and the outer substrate. The second adhesive is disposed between the display panel and the cover. The display panel includes a flexible substrate and a display layer disposed between the flexible substrate and the cover. The display layer includes a self-emissive display element or a non-self-emissive display element. The flexible substrate includes a first substrate, a second substrate, and a third adhesive disposed between the first substrate and the second substrate. The first substrate is disposed between the third adhesive and the display layer. A distance is between an edge of the first adhesive and an edge of the inner substrate. The distance is greater than zero.