Polyimide-Polysiloxane Composite Substrate for Flexible Displays
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Solution Overview
Problem
Existing polyimide substrates for flexible displays suffer from high coefficient of thermal expansion (CTE), leading to warpage and alignment accuracy issues, and require complex production processes, while current methods for reducing CTE and birefringence limit monomer design freedom and introduce defects during heating.
Innovation Solution
A substrate with a polysiloxane resin layer on a polyimide resin layer, incorporating inorganic oxide particles to reduce CTE and birefringence, allowing for high-definition display manufacturing without complex operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a transparent polyimide substrate is used for flexible displays, then flexibility and light transmission are improved, but the coefficient of thermal expansion becomes large causing warpage and alignment accuracy deterioration
Solution Approach 1:
The patent uses a composite structure consisting of a polyimide resin layer and a polysiloxane resin layer. The polyimide layer provides flexibility and light transmission, while the polysiloxane layer with inorganic oxide particles reduces the coefficient of thermal expansion. This composite material approach allows the substrate to maintain both flexibility and low CTE, preventing warpage and alignment accuracy deterioration during manufacturing and operation.
2Manufacturing precision
If the CTE of polyimide substrate is reduced to prevent warpage, then manufacturing precision is improved, but monomer design freedom is limited and defects occur during heating
Solution Approach 1:
Instead of modifying the polyimide monomer structure which limits design freedom and causes heating defects, the patent introduces a separate polysiloxane resin layer containing inorganic oxide particles. This composite approach reduces CTE effectively while maintaining the original polyimide composition and manufacturing process, avoiding monomer design constraints and heating-related defects.
Solution Approach 2:
The polysiloxane resin layer acts as an intermediary material that mediates the thermal expansion behavior of the substrate. By incorporating inorganic oxide particles into the polysiloxane layer, the overall CTE of the composite substrate is reduced without directly modifying the polyimide resin, thus simplifying the production process and avoiding defects associated with monomer modifications.
3Reliability
If a gas barrier film is formed on polyimide substrate, then protection is improved, but cracks and wrinkles form due to CTE difference between polyimide and silicon oxide/nitride
Solution Approach 1:
The patent creates a composite substrate with polyimide and polysiloxane resin layers where the polysiloxane layer has a CTE intermediate between polyimide and silicon oxide/nitride gas barrier films. This gradient CTE structure reduces the thermal stress difference at interfaces, preventing cracks and wrinkles in the gas barrier film while maintaining protection functionality.
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 substrate achieves low CTE, reduced birefringence, and flexibility, enabling high-definition displays with improved processing accuracy and crack resistance, while simplifying production and reducing defects.
Implementation Method 1
the film B contains inorganic oxide particles therein
Implementation Method 2
incorporating inorganic oxide particles to reduce CTE and birefringence
Data Source
AI summary
The present invention is a substrate for a display, the substrate having a film B including a polysiloxane resin on at least one surface of a film A including a polyimide resin, wherein the film B contains inorganic oxide particles therein, and the present invention has an object to provide a substrate for a display: being able to be applied to a color filter, an organic EL element, or the like without the need to carry out any complex operations; allowing high-definition displays to be manufactured; and being provided with a low CTE, a low birefringence, and flexibility.