Rollable Display Module Supporter Strain Gradient
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Solution Overview
Problem
Rollable display devices face challenges in maintaining flatness and surface quality when unrolled, leading to deformation and potential interfacial delamination due to differences in modulus between support layers and support bars.
Innovation Solution
A module supporter structure is introduced, comprising a support layer with a modulus between 10 KPa and 100 KPa, coating layers with a modulus between 100 MPa and 10 GPa, and support bars with a modulus between 50 GPa and 500 GPa, where the coating layers have a modulus greater than the support layer but less than the support bars, and are arranged to absorb strain and enhance adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple support layer structure is used, then the device complexity is reduced, but the surface quality and flatness of the display module deteriorates
Solution Approach 1:
The module supporter uses a composite structure consisting of a support layer and multiple coating layers with different moduli. The support layer provides base support while the coating layers with progressively higher moduli (from first to fourth layer) create a gradient structure that effectively distributes stress and maintains surface flatness, solving the contradiction between structural simplicity and surface quality.
Solution Approach 2:
Different regions of the module supporter have different structural properties. The coating layers are strategically positioned with varying moduli to address local stress distribution needs. The first coating layer (1-10 GPa) is closer to the display module while the fourth coating layer (10-100 GPa) is farther away, creating localized stiffness variations that optimize both structural integrity and surface quality.
2Strength
If support bars with high modulus are used directly without intermediate layers, then the strength is improved, but interfacial delamination occurs due to modulus mismatch
Solution Approach 1:
The patent introduces a gradual change in the modulus parameter across the coating layers. The first coating layer has a modulus of 1-10 GPa, the second layer has 10-50 GPa, the third layer has 50-100 GPa, and the fourth layer has 100-500 GPa. This progressive parameter transition creates a modulus gradient that bridges the gap between the soft support layer and the stiff support bars, preventing interfacial delamination while maintaining structural strength.
Solution Approach 2:
The multiple coating layers act as intermediary elements between the support layer and support bars. Each coating layer serves as a transition zone that mediates the mechanical stress transfer, gradually adapting from the compliant support layer to the rigid support bars, thereby preventing direct mechanical conflict and interface failure.
3Stability of the object's composition
If the modulus of the support layer is increased to improve rigidity, then the stability is improved, but the surface flatness when unrolled deteriorates
Solution Approach 1:
The module supporter structure is designed to be dynamically adaptive to the display module's state. When the display module is rolled, the support structure provides stability through the layered composite design. When unrolled, the gradient modulus structure allows the support layer to remain compliant (10-100 KPa) for flatness while the coating layers progressively increase in stiffness to maintain overall structural stability, creating a dynamic response to different operational states.
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
This configuration reduces deformation, improves surface quality, and prevents interfacial delamination by distributing strain evenly, allowing for a more stable and flat display surface when the device is unrolled.
Implementation Method 1
a plurality of coating layers disposed in the support layer and surrounding at least a portion of the plurality of support bars. The plurality of coating layers has a modulus greater than a modulus of the support layer and smaller than a modulus of the plurality of support bars
Data Source
AI summary
A display device includes a display module rolled in a second direction crossing a first direction with respect to a rolling axis extending in the first direction and a module supporter disposed under the display module. The module supporter includes a support layer, a plurality of coating layers disposed in the support layer, extending in the first direction, and arranged in the second direction, and a plurality of support bars each being disposed in a corresponding coating layer among the plurality of coating layers.