Curved Display Bonding Layer with Variable Elasticity Modulus
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Solution Overview
Problem
Current liquid crystal display modules with curved surfaces experience stress-induced Mura phenomena and reduced display quality due to uneven bonding on protrusions or depressions, leading to poor curvature stability and increased stress on the display panel.
Innovation Solution
A display module design featuring a bonding layer with a first bonding portion and a second bonding portion, where the second bonding portion has a lower elasticity modulus than the first, using a combination of solid and liquid adhesives to distribute stress uniformly and maintain curvature stability, along with a die-casting process for the back panel and cold-bending for the cover board to ensure consistent curvature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If double sided adhesive is used to fix the cover board to the back panel in a curved display device, then the cover board can be fixed to the back panel, but extra local stress is caused due to protrusions or depressions on the sticking surface, leading to serious Mura phenomenon and reduced display effect
Solution Approach 1:
The bonding layer is designed with different elasticity moduli in different regions: the first elasticity modulus in the first region and the second elasticity modulus in the second region, where the second elasticity modulus is less than the first elasticity modulus. This local differentiation allows the bonding layer to adapt to the curved surface characteristics, reducing stress concentration in specific areas and thereby minimizing the Mura phenomenon while maintaining adequate bonding strength.
Solution Approach 2:
The patent changes the elasticity modulus parameter of the bonding layer material to resolve the contradiction. By selecting a bonding layer material with appropriate elasticity modulus values (where the second elasticity modulus is less than the first elasticity modulus), the bonding layer can effectively distribute stress on the curved surface, reducing the Mura phenomenon while maintaining bonding strength.
2Device complexity
If a uniform bonding layer is used to bond the cover board to the back panel, then the bonding structure is simple, but stress distribution is uneven on curved surfaces, causing Mura phenomenon
Solution Approach 1:
The bonding layer is designed with different elasticity moduli in different regions: the first elasticity modulus in the first region and the second elasticity modulus in the second region, where the second elasticity modulus is less than the first elasticity modulus. This local differentiation allows the bonding layer to adapt to the curved surface characteristics, reducing stress concentration in specific areas and thereby minimizing the Mura phenomenon while maintaining adequate bonding strength.
3Shape
If the back panel is made curved to meet vehicle-mounted display requirements, then the display can accommodate large size and curved surface requirements, but local protrusions or depressions are created on the sticking surface, causing extra local stress
Solution Approach 1:
The patent changes the elasticity modulus parameter of the bonding layer material to resolve the contradiction. By selecting a bonding layer material with appropriate elasticity modulus values (where the second elasticity modulus is less than the first elasticity modulus), the bonding layer can effectively distribute stress on the curved surface, reducing the Mura phenomenon while maintaining bonding strength.
Solution Approach 2:
The bonding layer acts as an intermediary between the cover board and the back panel. With its specially designed elasticity modulus distribution, it mediates the stress transmission between these two components, absorbing and distributing the local stress caused by the curved surface geometry, thereby preventing stress concentration and Mura phenomenon.
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 effectively reduces stress on the display panel, improves curvature stability, and minimizes the Mura phenomenon, enhancing the overall display quality and reliability of the module.
Implementation Method 1
an elasticity modulus of the second bonding portion is smaller than that of the first bonding portion
Data Source
AI summary
A display module is provided that includes a curved back panel including a bottom board and a side frame disposed on the bottom board; a display assembly located in an accommodation space enclosed by the side frame and the bottom board; a cover board located on a side, away from the bottom board, of the display assembly and supported by the side frame; and a bonding layer including a first bonding portion and a second bonding portion, which are located between the cover board and the side frame. Both the first bonding portion and the second bonding portion are configured to bond the cover board to the side frame to enable the cover board to be curved. The second bonding portion has a smaller elasticity modulus than the first bonding portion. A method for manufacturing the display module, and a display apparatus are further provided.