Flexible Substrate Bonding via Edge-to-Edge Roll Contact
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Solution Overview
Problem
The challenge lies in bonding thin flexible substrates to carrier substrates without trapping air or particles, which is crucial for handling and processing in the display industry, especially for thin substrates used in high-quality display modules like LCDs, as existing methods often result in damage and air entrapment during transportation and processing.
Innovation Solution
A bonding method involving a flexible substrate wound on a rotating roller, where one edge is brought into contact with a carrier substrate and gradually bonded in a direction from one edge to the other, utilizing Van der Waals forces and capillary action, with optional air blowing and electrostatic discharge to minimize air trapping, and potentially conducted in a vacuum atmosphere to prevent air expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flexible substrate is bonded to the carrier substrate using conventional methods, then the substrate can be supported during handling, but air and particles become trapped in the bonding surface
Solution Approach 1:
The bonding process is divided into sequential stages: first bonding one edge portion of the flexible substrate to the carrier substrate, then gradually bonding the rest of the substrate in a controlled manner. This segmentation allows air to escape from the bonding surface as the substrate is progressively attached, preventing air pockets while maintaining strong bonding.
Solution Approach 2:
The flexible substrate is pre-wound on a rotating roller in a controlled manner before bonding. This preliminary arrangement ensures that the substrate is properly positioned and tensioned, allowing for uniform bonding pressure and preventing air entrapment during the subsequent bonding process.
2Ease of operation
If the thin substrate is transported alone, then handling is simple, but the substrate may be damaged or sag due to its thinness
Solution Approach 1:
The carrier substrate serves as an intermediary support structure. The flexible substrate is bonded to the carrier substrate, which provides mechanical strength and rigidity during transportation and processing. The carrier substrate acts as a mediator that protects the thin flexible substrate from damage while allowing the flexible substrate to maintain its flexibility for subsequent separation.
3Object-generated harmful factors
If air is blown onto the flexible substrate during bonding, then air trapping is reduced, but the process complexity increases
Solution Approach 1:
Air is blown onto the flexible substrate during the bonding process using a pneumatic system. This airflow removes trapped air and prevents bubble formation at the bonding interface. The pneumatic approach is integrated into the bonding apparatus, providing a relatively simple and effective method to eliminate air trapping without significantly increasing overall process complexity.
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 significantly reduces air trapping between the substrates, enhancing bonding quality and preventing damage during handling and post-processing, even in vacuum conditions, thus facilitating the fabrication of high-quality display modules.
Implementation Method 1
bonding the flexible substrate wound on a rotating roller onto the carrier substrate
Implementation Method 2
blowing air onto the flexible substrate in the direction from the one edge portion toward the other edge portion from above the flexible substrate
Implementation Method 3
utilizing Van der Waals forces and capillary action
Data Source
AI summary
The present invention relates to a flexible substrate bonding method and, more particularly, to a bonding method for bonding a flexible substrate to a carrier substrate in order to facilitate handling of the flexible substrate. To this end, the present invention provides a flexible substrate bonding method comprising: a substrate preparation step for preparing a carrier substrate and a flexible substrate; and a bonding step for bonding the carrier substrate to the flexible substrate, which rotates by being wound around a rotation roll, while moving the carrier substrate by a transfer unit, wherein the bonding step includes bringing one edge of the flexible substrate into contact with the carrier substrate, and then gradually bonding the flexible substrate to the carrier substrate in a direction from one side to the other side.