Flexible Display Module Strain Distribution via Film Layer Ratios
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Solution Overview
Problem
Flexible display modules with multiple film layers experience strain accumulation during curling, leading to peeling and potential fracture of key layers such as the inorganic encapsulation layer and back plate, especially with increased curling turns.
Innovation Solution
A flexible display module design featuring a first and second functional film layer with specific thickness and elasticity modulus ratios, asymmetric or symmetric configurations, and inclusion of materials like polyimide organic materials, impact absorption layers, and patterned metal layers to distribute strain evenly and enhance curling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple film layers are adhered by glue to form a flexible display module, then the module can be constructed with necessary functional layers, but strain accumulation occurs during curling leading to peeling and potential fracture
Solution Approach 1:
The patent changes the physical parameters of the adhesive layer by introducing a specific modulus of elasticity range (0.5-5 Gpa) and thickness range (10-50 μm). This parameter optimization allows the adhesive layer to effectively absorb strain during curling while maintaining proper adhesion, resolving the contradiction between having multiple functional layers and preventing strain accumulation
Solution Approach 2:
The patent creates a composite structure by combining the adhesive layer with specific functional film layers (cover plate, back plate, encapsulation layers) where each component has optimized mechanical properties. The adhesive layer acts as a strain-absorbing element within this composite structure, allowing the overall module to curl without peeling or fracture
2Adaptability or versatility
If the number of curling turns is increased, then the flexibility and adaptability of the display module is improved, but strain accumulation becomes more serious leading to peeling and fracture
Solution Approach 1:
The adhesive layer is designed beforehand as a cushioning element with specific mechanical properties (modulus of elasticity 0.5-5 Gpa, thickness 10-50 μm) that enable it to absorb strain energy during curling. This pre-designed cushioning capacity allows the module to withstand multiple curling turns without accumulating excessive strain that would cause peeling or fracture
3Reliability
If adhesive materials are used to absorb strain accumulation, then some strain can be mitigated, but when strain reaches the limit value, peeling occurs and key layers fracture
Solution Approach 1:
The patent optimizes the adhesive layer parameters (modulus of elasticity: 0.5-5 Gpa, thickness: 10-50 μm) to change its strain absorption capacity. These parameter changes enable the adhesive to absorb strain up to higher limits without reaching the critical point where peeling and fracture occur, thereby resolving the contradiction between strain absorption capability and prevention of harmful effects
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 design significantly reduces strain accumulation on key layers, preventing peeling and fracture during curling, thereby improving the module's curling performance and product quality.
Implementation Method 1
the ratio of the elasticity modulus of the second functional film layer to the elasticity modulus of the first functional film layer is from 0.5 to 1.5
Data Source
AI summary
The flexible display module can be curled, and may comprise: a flexible display panel having a display side and a rear side which are provided opposite to each other in a thickness direction of the flexible display panel; a first functional film layer, formed on a display side of the flexible display panel; and a second functional film layer, formed on the rear side of the flexible display panel. The ratio of the thickness of the second functional film layer to the thickness of the first functional film layer is 0.5 to 1.5, and the ratio of the elasticity modulus of the second functional film layer to the elasticity modulus of the first functional film layer is 0.5 to 1.5. The flexible display module is not prone to peeling, losing efficacy and the like.