Plastic Window Bonding via Dual-Film Insert Molding
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Solution Overview
Problem
Conventional display devices with glass windows are prone to breakage in portable devices, and plastic windows, while flexible, often increase thickness and manufacturing time due to adhesive layers and can be bent during production, affecting the device's shape and reliability.
Innovation Solution
A display device with a plastic window comprising a light transmittance film and a polymer layer, bonded without adhesives, where the films are stacked and injected with molten polymer, allowing for a dual-film insert molding process that prevents asymmetric stress and maintains symmetric stress, thus avoiding bending and simplifying manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an adhesive layer is used to bond the plastic window to the display panel, then the bonding strength is improved, but the thickness of the display device increases and the manufacturing time is prolonged
Solution Approach 1:
The adhesive layer is completely removed from the structure. The plastic window is bonded directly to the display panel through surface treatment (plasma or corona treatment) of the plastic window's inner surface, eliminating the need for any adhesive material while maintaining bonding strength.
Solution Approach 2:
Surface treatment (plasma or corona treatment) acts as an intermediary mechanism to create bonding between the plastic window and display panel without requiring adhesive material. The treatment modifies the surface energy and chemical properties of the plastic window to enable direct adhesion.
2Strength
If an adhesive layer is used to bond the plastic window, then the bonding strength is improved, but the manufacturing time is prolonged due to the adhesion process
Solution Approach 1:
The adhesive layer and associated adhesion processes are completely eliminated. The plastic window is bonded directly to the display panel through surface treatment, removing the time-consuming steps of adhesive application, positioning, and curing that are inherent in traditional adhesive-based bonding.
Solution Approach 2:
Surface treatment (plasma or corona treatment) serves as a rapid intermediary process that enables direct bonding without adhesives. This treatment can be performed in-line during the manufacturing process, significantly reducing the overall manufacturing time compared to traditional adhesive application and curing processes.
3Strength
If the plastic window is assembled with adhesive layers, then the bonding is improved, but the plastic window may be bent during manufacturing affecting shape and reliability
Solution Approach 1:
The adhesive layer is removed entirely, eliminating the source of asymmetric stress that causes bending. The direct bonding through surface treatment creates a more uniform stress distribution across the plastic window, preventing deformation during the assembly process.
Solution Approach 2:
Surface treatment acts as a uniform intermediary across the entire bonding interface, creating consistent adhesion forces that distribute stress evenly. This prevents the localized stress concentrations that occur with adhesive layers, thereby maintaining the plastic window's shape and preventing bending during manufacturing.
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 solution reduces the thickness of the display device, enhances its reliability by preventing bending, and streamlines the manufacturing process by eliminating the need for adhesive layers, while maintaining high temperature and humidity reliability.
Implementation Method 1
injecting a molten polymer between the light transmittance film and the functional film and compressing the light transmittance film and the functional film
Implementation Method 2
injecting a molten polymer between the light transmittance film and the functional film
Implementation Method 3
injecting a molten polymer between the light transmittance film and the functional film and compressing the light transmittance film and the functional film
Data Source
AI summary
A display device including: a plastic window including a light transmittance film and a polymer layer, and a functional film including a touch screen panel film, a polarizing film, or a combination thereof. The light transmittance film, the polymer layer, and the functional film are sequentially stacked on each other, and the light transmittance film, the functional film, and the polymer layer are attached to each other by a plastic. A method of manufacturing the same is also provided.