Display Panel Bonding Dam Structure to Prevent Adhesive Overflow
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Solution Overview
Problem
Adhesive with low viscosity used in dam and fill processes for attaching a transparent panel to a display panel with a bezel-covered perimeter can enter gaps and cause short circuits or optical path contamination, leading to reduced display reliability.
Innovation Solution
A manufacturing process using a dispenser and UV irradiation devices to create a dam with high-viscosity adhesive that straddles the bezel, ensuring the adhesive remains within the gap and is fully cured, preventing adhesive overflow and ensuring reliable attachment of a transparent panel to a display panel with a bezel-covered perimeter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive with low viscosity is used to fill the dam, then the adhesive can flow smoothly and fill the gap effectively, but the adhesive may overflow the dam and enter the gap between the display panel and bezel
Solution Approach 1:
A first adhesive with high viscosity is applied to form a dam structure before filling with the second low-viscosity adhesive. This preliminary high-viscosity layer creates physical barriers (protrusions) that constrain the subsequent low-viscosity adhesive, preventing overflow while allowing smooth filling of the intended gap area.
Solution Approach 2:
The adhesive system uses two different adhesives with different viscosities in different locations: a high-viscosity first adhesive for the dam structure requiring containment, and a low-viscosity second adhesive for the filling area requiring flow. This local differentiation of material properties solves both the smooth filling requirement and the overflow prevention requirement.
2Strength
If a bezel is attached to the display panel to restrict warp, then the rigidity of the display panel is increased, but the gap between the display panel and bezel becomes a pathway for adhesive overflow
Solution Approach 1:
The first high-viscosity adhesive is applied in advance to form a dam structure that extends onto the bezel surface, creating protrusions that act as physical barriers. This preliminary structure prevents the subsequently applied low-viscosity adhesive from entering the gap between the display panel and bezel, while the bezel itself maintains its warp-restricting function.
Solution Approach 2:
The first adhesive dam acts as an intermediary barrier between the second adhesive and the gap between display panel and bezel. This intermediate structure allows the bezel to maintain its structural function while preventing harmful adhesive infiltration into the gap area.
3Strength
If light curable resin is used as adhesive, then the adhesive provides strong bonding when cured, but uncured adhesive that enters the gap causes short circuits and optical path contamination
Solution Approach 1:
The first light-curable adhesive is applied first to form a dam structure, and UV light is radiated to cure this dam before applying the second adhesive. This preliminary curing creates a solid barrier that prevents uncured second adhesive from entering the gap, while the final curing of the second adhesive provides the bonding strength for attaching the transparent panel.
Solution Approach 2:
The adhesive application process is segmented into two distinct stages: first, forming and curing a dam structure with high-viscosity adhesive to create containment barriers; second, filling and curing low-viscosity adhesive for bonding. This segmentation ensures that uncured adhesive is contained within defined boundaries, preventing harmful overflow while maintaining strong bonding.
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 process ensures high reliability of the display by preventing adhesive overflow and ensuring complete curing, thereby avoiding short circuits and optical path contamination, while reducing the need for additional sealing members and lowering manufacturing costs.
Implementation Method 1
light is radiated to the dam to cure the dam
Data Source
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AI summary
A display comprising a display panel (24), a bezel (26) disposed to cover a periphery of a front surface (24a) of the display panel(24), a first adhesive (52) disposed like a dam to straddle the front surface (24a) of the display panel (24) and the bezel (26), a second adhesive (54) filled in the dam, and a transparent panel (22) stuck to the front surface (24a) of the display panel (24) with the first and the second adhesives, wherein the dam (56) is continuous, along an inner peripheral edge of the bezel (26), and has a low-protrusion portion (56a) that has a height (H1) from the front surface (24a) of the display panel (24) lower than the height (HO) of another portion of the dam from the front surface (24a) of the display panel (24), thereby leaving a gap between low-protrusion portion (56a) and the transparent panel (22) configured to allow air between transparent panel (22) and display panel (24) to be smoothly removed while the transparent panel (22) is stuck to the display panel (24), the second adhesive (54) sealing the gap between low-protrusion portion (56a) and transparent panel (22).