Auxetic Rollable Display Module Structure for Crease Reduction
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Solution Overview
Problem
Existing rollable display devices suffer from creases and degraded surface quality due to mechanical deformation during repeated rolling and unrolling.
Innovation Solution
A display device with a rolling shaft and a display module incorporating an auxetic structure, which includes areas with varying elastic moduli and a support layer with support sticks, to minimize stress and crease formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the display module is rolled on the rolling shaft, then the display device achieves compact form factor and portability, but creases and surface quality degradation occur due to mechanical deformation
Solution Approach 1:
The auxetic structure is designed with spatially varying unit cell configurations where the geometry and density of unit cells are adjusted locally across different regions of the support layer. This local variation in structural properties allows different zones to accommodate varying stress distributions during rolling, preventing uniform crease formation while maintaining overall surface quality.
Solution Approach 2:
The support layer is constructed as a composite structure combining the auxetic patterned layer with the adhesive layer, creating a multi-layer composite material system. This composite structure integrates the mechanical benefits of auxetic materials (negative Poisson's ratio, enhanced elasticity) with the bonding capabilities of the adhesive layer, providing both structural support and crease prevention during rolling operations.
2Ease of manufacture
If a uniform support structure is used below the display panel, then the manufacturing process is simplified, but stress distribution during rolling is uneven causing creases
Solution Approach 1:
The support layer is segmented into numerous discrete unit cells arranged in a periodic auxetic pattern. Each unit cell acts as an independent structural element that can deform and redistribute stress locally. This segmentation transforms the continuous support layer into a modular structure that maintains manufacturing simplicity through repetitive patterns while achieving superior stress distribution uniformity during rolling.
Solution Approach 2:
The auxetic structure utilizes changes in geometric parameters of the unit cells (such as cell size, shape, and spacing) to control the mechanical properties of the support layer. By adjusting these parameters, the structure achieves enhanced elasticity and stress distribution capabilities without fundamentally changing the manufacturing approach, maintaining ease of production while improving reliability.
3Adaptability or versatility
If the display module is repeatedly rolled and unrolled, then the display device achieves flexibility and adaptability, but mechanical deformation accumulates causing creases and surface degradation
Solution Approach 1:
The auxetic structure is pre-configured in the support layer before the display module undergoes repeated rolling operations. This preliminary structural arrangement provides built-in stress absorption and distribution capabilities that actively counteract mechanical deformation from the outset. The pre-designed unit cell geometry prepares the support layer to accommodate cyclic loading, preventing cumulative damage and maintaining surface integrity over multiple rolling cycles.
Solution Approach 2:
The auxetic patterned support layer acts as a cushioning structure that absorbs and dissipates mechanical stresses before they can propagate to the display panel surface. The negative Poisson's ratio characteristics of the auxetic structure enable it to expand laterally when compressed, creating a cushioning effect that protects the display surface from creases and deformation during repeated rolling and unrolling operations.
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 auxetic structure effectively reduces creases and enhances surface quality by improving rollability and maintaining a smooth display surface.
Implementation Method 1
The auxetic structure includes a first area and a second area having a higher elastic modulus than the first area
Implementation Method 2
A display device with a rolling shaft and a display module incorporating an auxetic structure
Data Source
AI summary
A display device includes a rolling shaft having a step and a display module coupled to the rolling shaft to fill the step. The display module includes a display panel and an auxetic structure disposed below the display panel. The auxetic structure includes a first area and a second area having a higher elastic modulus than the first area, and a flat area is disposed between a rotational axis and the second area in a state in which the display module is rolled on the rolling shaft.