Flexible Display Substrate Separation via Joule Heating
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Solution Overview
Problem
Conventional flexible display devices face challenges in flexibility due to the use of glass substrates, which limits their application and increases processing costs, especially when separating the flexible substrate from the carrier substrate without damaging the thin film transistor.
Innovation Solution
A method involving the formation of a heat generator on a carrier substrate, a flexible substrate with a thin film transistor and light emitting element, and separating the flexible substrate using heat generated by the heat generator, which includes Joule heating to decompose the sacrificial layer and separate the substrate, maintaining the integrity of the thin film transistor and reducing processing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a glass substrate is used to maintain structural integrity, then the display device achieves high strength and stability, but flexibility is reduced and processing costs increase
Solution Approach 1:
The substrate is divided into two functional parts: a glass carrier substrate that provides structural strength and stability, and a flexible substrate that enables flexibility and bending capabilities. This segmentation allows each part to fulfill its specific function without compromise.
Solution Approach 2:
A sacrificial layer is introduced as an intermediary between the glass carrier substrate and the flexible substrate. This layer enables the flexible substrate to be temporarily supported during manufacturing while allowing for clean separation afterward, achieving both strength and flexibility.
2Ease of manufacture
If the flexible substrate is separated from the carrier substrate using conventional methods, then the substrate can be transferred, but the thin film transistor is damaged
Solution Approach 1:
The sacrificial layer acts as a mediator that facilitates separation between the carrier substrate and flexible substrate. When removed, it enables clean detachment without applying damaging forces to the thin film transistor, achieving both ease of manufacture and device reliability.
Solution Approach 2:
The conventional mechanical separation methods that cause damage are replaced with a chemical dissolution process. The sacrificial layer is removed through chemical etching or dissolution, which gently releases the flexible substrate without mechanical stress on the thin film transistor.
3Productivity
If the separation process is performed quickly to reduce processing time, then productivity increases, but the thin film transistor is damaged
Solution Approach 1:
Fast mechanical separation methods are replaced with a chemical dissolution process of the sacrificial layer. This chemical approach allows rapid removal of the sacrificial layer and quick substrate separation without applying mechanical stress that would damage the thin film transistor, achieving both high productivity and device reliability.
4Device complexity
If conventional separation methods are used, then the process is simple, but processing costs increase due to damage and rework
Solution Approach 1:
The sacrificial layer is formed in advance during the manufacturing process, before the flexible substrate is fully processed. This preliminary action prevents the need for complex damage repair processes later, reducing overall manufacturing costs while maintaining process simplicity.
Solution Approach 2:
The sacrificial layer serves as a temporary intermediary that simplifies the overall manufacturing process by enabling clean separation. Although it adds one more layer to form, it eliminates the need for complex damage repair processes, resulting in lower overall processing costs and maintained process simplicity.
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 efficient manufacturing of flexible display devices with minimal damage to the thin film transistor and reduced processing costs, achieving a smooth separation process that maintains the quality of the display device, with a root mean squared roughness of the flexible substrate surface within 1 nm to 15 nm.
Implementation Method 1
Generating Joule's heat by applying a voltage to the heat generator, the generated Joule's heat being applied to the flexible substrate to separate the flexible substrate from the heat generator
Implementation Method 2
forming the heat generator includes forming a heat generator transmitting heat to the flexible substrate
Data Source
AI summary
A method for manufacturing a flexible display device includes forming a heat generator on a carrier substrate, forming a flexible substrate on the heat generator, forming a thin film transistor on the flexible substrate, forming a light emitting element connected to the thin film transistor, and separating the flexible substrate from the heat generator by application of heat to the flexible substrate, the application of heat including generation of heat by the heat generator.