Foldable Display Stiff Support Layer Hinge Discontinuity
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Solution Overview
Problem
Foldable displays face issues with insufficient support from hinge systems, leading to discontinuities and poor operation, causing user frustration due to damage from localized loads and pressure applied during folding.
Innovation Solution
A foldable display stack-up with multiple layers, including a stiff support layer made of materials like metal, glass, or ceramic, which provides significant stiffness to prevent damage from pressure and discontinuities, and is bound to a display layer and cover lens using adhesives, ensuring the display remains intact during folding and unfolding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a hinge system is used to allow folding, then the display can be folded, but the hinge system provides insufficient support to the display
Solution Approach 1:
The support structure is divided into multiple discrete support layers (first support layer, second support layer, third support layer) positioned at different locations within the display stack. Each support layer provides localized reinforcement, allowing the display to maintain structural integrity while enabling folding through the hinge system.
Solution Approach 2:
The display incorporates multiple support layers made of different materials (such as polymer support layers and rigid support layers) with varying mechanical properties. These composite structures provide optimized support characteristics - the polymer layers offer flexibility while the rigid layers provide structural strength, collectively enhancing display support during folding operations.
2Area of moving object
If the display is made foldable to increase screen size, then the display size increases, but discontinuities occur in the display
Solution Approach 1:
Support layers are pre-positioned within the display stack at strategic locations before the folding operation occurs. The first support layer is positioned adjacent to the display layer at the fold line, while additional support layers are positioned at predetermined distances from the fold line. This preliminary structuring prevents discontinuities from forming during the folding and unfolding cycles.
Solution Approach 2:
Different support layers are positioned at different locations within the display stack to provide localized reinforcement where needed. The first support layer is positioned at the fold line where stress concentration occurs, while second and third support layers are positioned at predetermined distances to maintain display continuity in different regions, ensuring each area has the appropriate level of support for its specific functional requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The stiff support layer effectively prevents damage to the display and cover lens by distributing pressure and spanning discontinuities in the hinge system, maintaining the display's integrity and functionality across various bending cycles.
Implementation Method 1
The stiff support layer effectively prevents damage to the display and cover lens by distributing pressure and spanning discontinuities in the hinge system
Implementation Method 2
The stiff support layer is bound to an OLED display layer and a cover lens using adhesives
Data Source
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AI summary
A foldable display has multiple layers, including at least a display layer that creates the display that users see when looking at the foldable display and a stiff support layer that provides the display layer with support despite the foldable nature of the display. An adhesive layer binds the display layer to the stiff support layer. The stiff support layer has a stiffness that is at least six times greater than the stiffness of the adhesive layer and at least six times greater than the stiffness of the display layer. Given the foldable nature of the display, there is typically a hinge system below part of the display. In situations in which pressure is applied to the foldable display (e.g., by a user's finger or stylus), the stiffness of the stiff support layer prevents the display from being damaged despite the presence of the hinge system.