Encapsulant Sheet Viscosity Tuning for Uniform Display Lamination
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Solution Overview
Problem
Existing encapsulant sheets for self-luminous displays, such as micro LED televisions, face challenges in maintaining uniform film thickness and preventing excessive resin flow during hot pressing, leading to defects and suboptimal display quality.
Innovation Solution
A resin encapsulant sheet with a polyolefin base and specific melt viscosity range at 120°C, combined with a silane component in the adhesive layer, ensures optimal molding properties and adhesion while preventing resin flow and ensuring uniform film thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If encapsulant sheet with lower melt viscosity is used to improve molding properties, then ease of manufacture is improved, but resin flow becomes excessive leading to defects
Solution Approach 1:
The patent applies parameter changes by precisely controlling the melt viscosity of the encapsulant sheet within a specific range (5.0×10³ to 1.0×10⁵ poise at 120°C and shear rate of 2.43×10⁴ sec⁻¹). This optimized viscosity parameter enables the resin to flow sufficiently for complete encapsulation while preventing excessive flow that would cause defects, thus resolving the contradiction between ease of manufacture and manufacturing precision.
2Manufacturing precision
If encapsulant sheet with higher melt viscosity is used to prevent resin flow, then manufacturing precision is improved, but molding properties deteriorate
Solution Approach 1:
The patent resolves this contradiction by establishing an optimal melt viscosity range (5.0×10³ to 1.0×10⁵ poise at 120°C) that balances flow control and molding capability. The controlled viscosity prevents resin flow defects while maintaining sufficient fluidity for complete encapsulation, achieving both manufacturing precision and ease of manufacture simultaneously.
3Strength
If adhesive layer with higher silane component content is used to improve adhesion, then strength is improved, but adhesion becomes excessive causing peeling difficulties
Solution Approach 1:
The patent applies parameter changes by controlling the silane component content in the adhesive layer within a specific range (0.02% to 0.15% by mass relative to resin component). This optimized concentration provides sufficient adhesive strength for reliable bonding while preventing excessive adhesion that would make peeling difficult, thus resolving the contradiction between strength and ease of operation.
4Ease of operation
If adhesive layer with lower silane component content is used to improve peeling ease, then ease of operation is improved, but adhesive strength becomes insufficient
Solution Approach 1:
The patent resolves this contradiction by optimizing the silane component content to a specific range (0.02% to 0.15% by mass relative to resin component). This controlled concentration ensures adequate adhesive strength for reliable bonding while maintaining sufficient peeling ease for manufacturing flexibility, achieving both strength and ease of operation simultaneously.
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 encapsulant sheet provides superior adhesion, durability, and productivity for self-luminous displays by maintaining uniform film thickness and preventing defects, enhancing the overall quality and manufacturing efficiency.
Implementation Method 1
the adhesive layer contains polyolefin and a silane component, and content of the silane component relative to the resin component of the adhesive layer is at least 0.02% by mass and no more than 0.15% by mass
Implementation Method 2
the melt viscosity measured at a temperature of 120° C. and at a shear rate of 2.43×10⁴ sec⁻¹ is at least 5.0×10³ poise and no more than 1.0×10⁵ poise
Data Source
AI summary
An encapsulant sheet suitable for encapsulating a light-emitting element in, for example, a self-luminous display or for direct backlights. The encapsulant sheet is a single-layer or multi-layer resin sheet that includes an adhesive layer exposed at a topmost surface. The Vicat softening point is greater than 60° C. and no higher than 100° C. The melt viscosity of the encapsulant sheet, at a shear velocity of 2.43×10 sec−1 and measured at a temperature of 120° C. is at least 5.0×104 poise and no more than 1.0×105 poise. The adhesive layer contains a polyolefin and a silane component, and a content of the silane component relative to the resin component of the adhesive layer is at least 0.03% by mass and less than 10% by mass.