Optical Clear Adhesive Bonding for Flexible Panels
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Solution Overview
Problem
Existing vacuum bonding technologies are inadequate for bonding large-radian glass cover plates with flexible OLED panels, particularly in 180°-inverted bonding modes, leading to incomplete bonding, bubbles, and cracking due to limited profiling space and advanced contact issues.
Innovation Solution
A bonding method using a bonding jig with a sliding block and carrier film to apply optical clear adhesive, where the adhesive is heated to increase viscosity, allowing precise shaping and full bonding of flexible panels to large-radian protective cover plates, including 180°-inverted configurations, by controlling the sliding block's movement and heating the adhesive or bonding jig to prevent premature contact and ensure effective bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing vacuum bonding technology is used for bonding glass cover plates with flexible OLED panels, then the bonding process can be completed, but the bonding is incomplete and produces bubbles and cracks due to limited profiling space and advanced contact issues
Solution Approach 1:
The patent changes the temperature parameter of the optical clear adhesive during the bonding process. By heating the adhesive to a specific temperature range (50-60°C), its viscosity changes from less than 100 g/inch at normal temperature to greater than 2000 g/inch at elevated temperature. This parameter change enables the adhesive to maintain low viscosity during application (preventing bubbles and cracks) and then achieve high viscosity for strong bonding, thereby improving bonding quality without requiring complex multi-step processes
Solution Approach 2:
The patent applies preliminary heating to the optical clear adhesive before the bonding process. The adhesive is heated to the target temperature range prior to application, ensuring it achieves the correct viscosity state in advance. This preliminary action prevents premature contact and bonding issues during the actual bonding process, eliminating bubbles and cracks while simplifying the overall bonding procedure
2Manufacturing precision
If the optical clear adhesive is heated to increase viscosity for bonding, then complete bonding is achieved, but the adhesive may cause advanced contact and premature bonding in bending portions
Solution Approach 1:
The patent applies local heating to specific regions of the bonding jig corresponding to different bonding areas. The heating is localized rather than uniform, allowing different zones to be heated to appropriate temperatures for their specific bonding requirements. This local quality approach ensures precise bonding in each region while preventing excessive heating that could cause advanced contact and premature bonding in bending portions
Solution Approach 2:
The patent implements dynamic temperature control during the bonding process. The heating is applied selectively and can be adjusted in real-time based on the bonding stage and location. By dynamically controlling the temperature and heating duration, the system maintains the adhesive in the optimal viscosity range during application and then transitions to bonding temperature, preventing advanced contact issues while ensuring complete 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
This method improves bonding yield by preventing bubbles and cracks, ensuring complete bonding of flexible panels to large-radian and 180°-inverted protective cover plates, enhancing the quality and reliability of the bonding process.
Implementation Method 1
the optical clear adhesive is heated by heating the sliding block
Implementation Method 2
a viscosity of the heated optical clear adhesive is greater than the bondable threshold
Data Source
AI summary
A bonding method and a bonding device for a flexible panel. In the process of bonding a protective cover plate and the flexible panel, a heated-type optical adhesive is used, the optical adhesive at normal temperature has relatively low viscosity and the viscosity thereof is below a bondable threshold, so that before the flexible panel and the edge of the protective cover plate are bonded, the optical adhesive and the edge of the protective cover plate come into contact in advance and then can be effectively separated, thus poor bonding in a bending region is avoided, the risk of generating bubbles and cracks is small, and the bonding yield can be improved. Moreover, the optical adhesive is increased in viscosity after heated, thereby ensuring that the flexible panel is bonded to the protective cover plate.