Flexible Substrate with Asymmetric Base Layers for Display Devices
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Solution Overview
Problem
Existing flexible display devices face challenges with thickness, flexibility, manufacturing complexity, and adhesion issues, particularly due to the use of thick back plates and multi-layer buffer layers, which limit their size and increase manufacturing time.
Innovation Solution
A flexible substrate with a multi-layer structure comprising a first base layer, a second base layer with higher surface hardness, and a third base layer with higher adhesion strength, eliminating the need for a back plate and buffer layer, thereby enhancing flexibility, reducing thickness, and improving adhesion between the substrate and carrier substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thick back plate is used to protect the flexible substrate from external damage, then scratch resistance is improved, but device thickness increases and flexibility is reduced
Solution Approach 1:
The patent applies this principle by using a thin flexible substrate (10-50 μm) with integrated protective layers instead of a traditional thick back plate. The flexible substrate includes a lower base layer, lower inorganic insulation layer, and lower organic insulation layer that collectively provide protection while maintaining flexibility and reducing thickness to 100 μm or less.
Solution Approach 2:
The patent applies this principle by creating a composite structure where the flexible substrate integrates multiple materials: a polymer base layer (polyimide or polycarbonate), inorganic insulation layers (silicon oxide, silicon nitride, or silicon oxynitride), and organic insulation layers (benzocyclobutene). This composite structure provides both mechanical strength for scratch resistance and flexibility for bending.
2Object-affected harmful factors
If a multi-layer buffer layer is formed to prevent moisture permeation, then moisture barrier properties are improved, but manufacturing process complexity and time increase
Solution Approach 1:
The patent applies this principle by merging the buffer layer functions into the flexible substrate structure itself. The flexible substrate integrates the lower inorganic insulation layer and lower organic insulation layer that serve as built-in moisture barrier layers, eliminating the need for separate multi-layer buffer layers and simplifying the manufacturing process.
3Ease of operation
If the flexible substrate thickness is reduced to improve flexibility, then device flexibility is improved, but structural strength and protection capability are reduced
Solution Approach 1:
The patent applies this principle by using composite materials in the flexible substrate: a polymer base layer (10-50 μm thick) provides flexibility, while integrated inorganic insulation layers (silicon oxide, silicon nitride, or silicon oxynitride) and organic insulation layers (benzocyclobutene) provide structural strength and protection, achieving both flexibility and strength in a thin structure.
4Strength
If a back plate is attached through lamination process to protect the flexible substrate, then protection capability is improved, but manufacturing complexity increases for large area devices
Solution Approach 1:
The patent applies this principle by merging the protective back plate function directly into the flexible substrate structure. The flexible substrate itself becomes the protective layer through its integrated lower inorganic insulation layer and lower organic insulation layer, eliminating the need for a separate lamination process and simplifying manufacturing for large area devices.
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
The solution results in a thinner, more flexible display device with improved scratch resistance and moisture barrier properties, allowing for larger display areas and simplified manufacturing processes without the risk of substrate detachment.
Implementation Method 1
incorporating silane and siloxane compounds to enhance properties
Data Source
AI summary
A flexible display device is disclosed. The disclosed flexible display device includes a flexible substrate; a thin film transistor on the flexible substrate; and a light emitting diode or a liquid crystal capacitor connected to the thin film transistor. The flexible substrate includes: a first base layer; a second base layer on a first surface of the first base layer; and a third base layer on a second surface of the first base layer. A surface hardness of the second base layer is greater than a surface hardness of the third base layer, and an adhesion strength of the third base layer is greater than an adhesion strength of the second base layer.