Substrate Bonding via Peelable Light Barrier Frame
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Solution Overview
Problem
Existing methods for bonding substrates in display devices face issues with non-uniform adhesive thickness, bubble formation, adhesive overflow, and lack of adhesive, particularly around the edges, which affect the optical performance of touch modules.
Innovation Solution
A method involving a light barrier frame with an easily-removed layer, where a peelable adhesive is printed and cured, allowing for precise coating and precuring of a curable adhesive, followed by removal of the easily-removed layer to achieve a uniform adhesive layer with a smooth surface and controlled edge slope, enabling bonding of substrates with improved flatness and reduced defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If sealant bonding method is used, then bonding strength is improved, but gap formation occurs and optical performance deteriorates
Solution Approach 1:
The patent removes the sealant layer entirely and replaces it with a thin curable adhesive layer that provides both bonding and optical clarity. The easily-removed layer is extracted after serving its purpose as a coating guide, leaving no harmful gaps in the final structure.
Solution Approach 2:
The patent changes the thickness parameter of the adhesive layer from typical sealant thickness (creating gaps) to a thin curable adhesive layer (less than 10 micrometers). This parameter change eliminates gap formation while maintaining bonding strength and optical performance.
2Strength
If direct bonding with optical clear adhesive is used, then bonding strength is improved, but adhesive thickness uniformity deteriorates
Solution Approach 1:
The easily-removed layer acts as an intermediary between the coating head and the substrate, providing a stable surface for adhesive deposition. This intermediary layer ensures uniform adhesive thickness by preventing direct contact between the coating head and the flexible substrate, thereby improving manufacturing precision.
3Device complexity
If curable adhesive is coated without easily-removed layer, then process complexity is reduced, but adhesive thickness uniformity and surface flatness deteriorate
Solution Approach 1:
The easily-removed layer is applied in advance before curable adhesive coating. This preliminary action creates a stable coating surface that ensures uniform adhesive thickness and flat surface, while the layer itself is easily removed afterward without adding significant process complexity.
4Quantity of substance
If adhesive is coated in thick layer, then coverage is improved, but bubble formation and adhesive overflow increase
Solution Approach 1:
The patent changes the adhesive layer thickness parameter from thick to thin (less than 10 micrometers). This parameter change reduces the quantity of adhesive needed while preventing bubble formation and overflow, as the thin layer allows better control and reduces gravitational effects on the adhesive material.
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
This method ensures a uniform adhesive layer with reduced bubbles and adhesive defects, enhancing the optical performance of display devices by maintaining a consistent thickness and smooth surface, even for irregular shapes.
Implementation Method 1
the peelable adhesive comprises a light curing or heat curing material
Implementation Method 2
the peelable adhesive comprises a light curing or heat curing material
Implementation Method 3
which may be cured and cohered after suffering an irradiation or heating accordingly
Implementation Method 4
which may be cured and cohered after suffering an irradiation or heating accordingly
Data Source
Figure 1
Figure 2
Figure 3~6
AI summary
The present disclosure provides a method for bonding substrates, a touch substrate and a display device. In the process of manufacturing a touch display panel and the display device by the method for bonding substrates provided in the present disclosure, by steps such as arranging an easily-removed layer at a surrounding of a first substrate, coating and procuring light curing adhesive and removing the easily-removed layer, the light curing adhesive may be formed into a desired shape (including irregular shapes). In addition, an adhesive layer of the light curing adhesive has a uniform thickness, a smooth surface and an edge slope angle approaching to 90°. Furthermore, bonding bubbles may be reduced, and phenomenon such as lack of adhesive and adhesive overflow may be suppressed in the bonding process, thereby guaranteeing optical performance of the display device.