Thermal Sensitive Adhesive for Flexible OLED Encapsulation Peeling
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Solution Overview
Problem
The conventional flexible OLED device fabrication process faces a significant yield reduction due to the weak adhesion between the thin film encapsulation layer and the OLED display unit, leading to separation issues when the glass carrier is peeled off.
Innovation Solution
A method is introduced where a thermal sensitive adhesive is used for the protective layer, allowing for controlled peeling by heating or cooling, reducing the adhesion and thereby minimizing the risk of stripping the encapsulation layer during the peeling process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a protective layer with optical clear adhesive is pressed onto the thin film encapsulation layer to prevent damage during subsequent processes, then the encapsulation layer is protected from mechanical damage, but the strong adhesion of the optical clear adhesive causes the thin film encapsulation layer to separate from the OLED display unit when the protective layer is peeled off
Solution Approach 1:
The patent changes the adhesion parameter of the protective layer by using thermal-sensitive adhesive instead of optical clear adhesive. The thermal-sensitive adhesive has temperature-dependent adhesion properties: strong adhesion at room temperature during processing, and weak adhesion at elevated temperatures during peeling. This parameter change resolves the contradiction by allowing strong protection during manufacturing while enabling easy removal without damaging the encapsulation layer.
Solution Approach 2:
The patent makes the adhesion property of the protective layer dynamic through the use of thermal-sensitive adhesive. The adhesive strength is not fixed but changes dynamically with temperature: high adhesion strength during the manufacturing process at room temperature, and low adhesion strength during the peeling process after heating. This dynamic behavior allows the same protective layer to serve opposite functions at different stages.
2Productivity
If the glass carrier is peeled off after thin film encapsulation to complete the flexible OLED device, then the flexible OLED device is finished and can be used, but the peeling process easily strips the thin film encapsulation film layer due to weak adhesion
Solution Approach 1:
The patent applies preliminary action by forming the thin film encapsulation layer with enhanced adhesion to the OLED display unit before the peeling process. The thermal-sensitive adhesive is specifically designed to maintain strong bonding at room temperature during all manufacturing steps, ensuring the encapsulation layer remains firmly attached to the OLED display unit until the final peeling stage when controlled heating is applied.
Solution Approach 2:
The patent utilizes phase transition of the thermal-sensitive adhesive through temperature change. The adhesive transitions from a high-adhesion state at room temperature to a low-adhesion state at elevated temperatures (typically above 60°C). This phase transition enables the peeling process to occur without stripping the encapsulation layer, as the adhesive strength is temporarily reduced during the heating phase of the peeling operation.
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 approach effectively reduces the stripping risk of the thin film encapsulation layer, enhancing the production yield by modifying the adhesive properties of the protective layer without compromising its main function.
Implementation Method 1
the protective layer is adhered to a surface of the encapsulation layer away from the OLED display unit by a thermal sensitive adhesive
Implementation Method 2
the step of removing the protective layer employs heating or cooling the protective layer
Implementation Method 3
the step of removing the protective layer includes providing a refrigerator to cool the protective layer
Data Source
AI summary
A method of fabricating a flexible organic light-emitting diode (OLED) display panel, the method comprising the steps of: step S1, providing a rigid substrate on which a flexible base is formed; step S2, forming a thin film transistor array layer on the flexible base; step S3, forming an OLED display unit on the thin film transistor array layer; step S4, forming an encapsulation layer on the OLED display unit; step S5, forming a protective layer on the encapsulation layer, wherein the protective layer is adhered to a surface of the encapsulation layer away from the OLED display unit by a thermal sensitive adhesive; step S6, peeling off the rigid substrate, and completing a support film to be attached under the flexible base; step S7, removing the protective layer; and step S8, forming a protective cover on the encapsulation layer.