Variable Thickness Adhesive for Display Stress Reduction
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Solution Overview
Problem
Display devices with optical-bonded display units face issues of increased weight due to larger screens, stress-induced display unevenness, and foreign matter entry, which affect yield and quality.
Innovation Solution
A display device design featuring a display unit bonded to a cover panel with optical adhesive and a holding frame using a variable thickness adhesive, allowing for reduced stress and improved assembly processes to prevent unevenness and foreign matter ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display screen size is increased to improve display area, then the display area is improved, but the weight of the display unit increases
Solution Approach 1:
The display device is divided into modular components: display unit, cover panel, and holding frame. This segmentation allows the large display unit to be supported and stabilized by the holding frame, distributing the weight burden and enabling larger screen sizes without excessive weight concentration in one component.
2Stability of the object's composition
If the display unit is bonded to the holding frame with rigid adhesive to improve structural stability, then structural stability is improved, but stress-induced display unevenness occurs
Solution Approach 1:
The adhesive thickness between the display unit and holding frame is changed from a fixed thin layer to a variable thickness configuration (5-20 μm at bonded portions, 20-50 μm at non-bonded portions). This parameter change allows the adhesive layer to absorb stress variations, maintaining structural stability while preventing display unevenness caused by rigid bonding.
Solution Approach 2:
The adhesive layer has different thicknesses in different locations: thinner (5-20 μm) where bonding occurs and thicker (20-50 μm) where no bonding occurs. This local quality variation provides both strong bonding where needed and stress absorption where needed, resolving the contradiction between structural stability and display uniformity.
3Object-affected harmful factors
If the display unit and cover panel are bonded first, then foreign matter entry is prevented, but assembly complexity increases
Solution Approach 1:
The display unit and cover panel are bonded together in advance before being mounted on the holding frame. This preliminary action creates a sealed unit that prevents foreign matter entry, while the modular design keeps the overall assembly process simple and manageable.
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 unit, suppresses display unevenness, and enhances manufacturing yield by allowing for pre-bonding of the display unit and cover panel, and corrects frame deformations before integration, ensuring a stable and foreign-matter-free assembly.
Implementation Method 1
The display surface of the display unit and the cover panel are bonded to each other with an optical adhesive material
Implementation Method 2
The holding frame and the display unit are bonded to each other with a variable thickness adhesive material a thickness of which is variable at least at a time of bonding the holding frame and the display unit
Data Source
AI summary
A display device includes a display unit having a display surface to display an image, a cover panel stacked on the display surface of the display unit, and a holding frame stacked on a back surface of the display unit. The display surface of the display unit and the cover panel are bonded to each other with an optical adhesive material. The holding frame and the display unit are bonded to each other with a variable thickness adhesive material a thickness of which is variable at least at a time of bonding the holding frame and the display unit.