Polyimide Adhesive Laser Delamination Flexible Displays
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Solution Overview
Problem
The existing methods for fabricating flexible display devices face challenges in using plastic substrates due to the difficulty in developing adhesive materials that can withstand high temperature processes and easily delaminate from carrier substrates, such as glass, during the fabrication of thin film transistors (TFTs).
Innovation Solution
A method involving the application of a polyimide-based adhesive layer on a carrier substrate, followed by the placement of a flexible substrate, formation of a TFT array, and separation of the carrier substrate using a laser beam, where the adhesive layer includes a mixture of polyimide and a coupler, and is heated to achieve strong adhesion and subsequent detachment at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an adhesive material is used to laminate the plastic substrate on the carrier substrate, then the plastic substrate can be held in place during fabrication, but the adhesive material cannot withstand high temperature processes
Solution Approach 1:
The adhesive material composition is changed from conventional adhesives to a specific polyimide-based formulation with modified chemical structure, enabling it to withstand high temperature processes (above 200°C) while maintaining adhesion strength during fabrication and allowing subsequent laser-induced delamination
Solution Approach 2:
A composite adhesive system is used consisting of polyimide base resin combined with specific couplers and additives, creating a multi-component material that simultaneously provides high temperature resistance, strong adhesion, and laser-responsive delamination properties
2Temperature
If the adhesive material is designed to withstand high temperature processes, then temperature resistance is improved, but the ability to easily delaminate the carrier substrate is reduced
Solution Approach 1:
The adhesive layer serves as an intermediary material with dual functionality: it provides strong bonding at high temperatures during fabrication, then acts as a laser-absorbing layer that mediates the energy transfer from laser beam to the adhesive-carrier interface, enabling controlled delamination without damaging the flexible substrate
Solution Approach 2:
The adhesive material undergoes phase transition or chemical decomposition when exposed to laser irradiation, transforming from a stable bonded state during high-temperature fabrication to a delaminating state under laser exposure, enabling easy separation of the carrier substrate
3Manufacturing precision
If a glass substrate is used, then manufacturing precision is improved, but flexibility is reduced
Solution Approach 1:
The substrate system is segmented into three distinct layers: the flexible plastic substrate (final product), the polyimide adhesive layer (functional intermediary), and the glass carrier substrate (temporary support). This segmentation allows the glass substrate to provide manufacturing precision while the flexible substrate provides the desired flexibility, with the adhesive layer enabling controlled separation
Solution Approach 2:
The polyimide adhesive layer acts as an intermediary between the glass carrier substrate and the flexible plastic substrate, allowing the system to benefit from both the manufacturing precision of glass and the flexibility of plastic. The adhesive layer enables the flexible substrate to be fabricated on the glass substrate while maintaining its inherent flexibility, then facilitates clean separation after fabrication
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 allows for the successful fabrication of flexible display devices that can withstand high temperature processes and easily separate the carrier substrate from the plastic substrate, ensuring reliable adhesion and detachment, thereby facilitating the production of flexible display devices with improved flexibility and reliability.
Implementation Method 1
separating the carrier substrate from the flexible substrate by irradiating a laser beam or light onto the adhesive layer
Implementation Method 2
heating the adhesive layer to a first temperature for a first amount of time after placing the adhesive layer on the surface of the carrier substrate, and heating the adhesive layer to a second temperature higher than the first temperature for a second amount of time
Data Source
AI summary
A method of fabricating a flexible display device, the method including applying an adhesive layer including polyimide on a carrier substrate, laminating a flexible substrate on the adhesive layer, and separating the carrier substrate from the flexible substrate by irradiating a laser beam or light onto the adhesive layer.