Paper Substrate with PET/PVDC Barrier for Flexible OLED
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Solution Overview
Problem
Existing OLED devices using glass substrates are inflexible and prone to fragility, while alternative materials like polymer films, ultra-thin glass, and metal foils suffer from thermal instability, high water and oxygen permeability, and complex processing issues, limiting their application. Paper, despite being cost-effective and widely available, also lacks toughness and is flammable and permeable to oxygen.
Innovation Solution
A substrate comprising a paper layer sandwiched between polyethylene terephthalate (PET) heat-sealable films coated with polyvinylidene chloride (PVDC) on both sides, with a hardened buffer layer produced by UV curable resin, is developed. This substrate is produced by drying the paper under vacuum, pressing it between steel plates, and bonding it with the PET films using a heat-sealing process to enhance moisture and oxygen barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass is used as substrate material, then OLED devices achieve good light-emitting performance, but the devices cannot bend and are prone to fragility
Solution Approach 1:
The patent replaces traditional glass substrates with flexible substrates composed of thin film layers including PET base film, PVDC barrier layer, and acrylic adhesive layer. This flexible substrate structure enables OLED devices to be bent and flexible while maintaining good light-emitting performance, directly resolving the contradiction between rigidity and flexibility.
2Adaptability or versatility
If polymer films are used as substrates, then OLED devices achieve flexibility, but the films have poor thermal stabilities and high water- and oxygen-permeabilities
Solution Approach 1:
The patent employs a composite substrate structure with multiple functional layers: PET base film provides mechanical strength and thermal stability, PVDC layer provides excellent water and oxygen barrier properties, and acrylic adhesive layer ensures strong bonding. This composite structure simultaneously achieves flexibility and reliability, resolving the contradiction between flexibility and barrier properties.
Solution Approach 2:
The PVDC barrier layer acts as an intermediary between the PET base film and the OLED functional layers, providing specialized water and oxygen barrier protection while the PET film provides thermal stability. This intermediary layering approach allows each material to perform its specialized function, resolving the contradiction between flexibility and barrier properties.
3Adaptability or versatility
If metal foils are used as substrates, then OLED devices achieve flexibility, but the surface roughness is high and the production process is complicated
Solution Approach 1:
The patent uses thin film composite structure (PET/PVDC/acrylic) as substrate that provides flexibility comparable to metal foils but with smooth surface quality suitable for OLED fabrication. The film-based approach also simplifies production processes compared to metal foil handling, resolving the contradiction between flexibility and ease of manufacture.
4Adaptability or versatility
If ultra-thin glass is used as substrate, then OLED devices achieve flexibility, but the toughness is insufficient and the price is high
Solution Approach 1:
The patent replaces ultra-thin glass with flexible thin film composite substrate that achieves comparable flexibility without the fragility issues. The film-based substrate also significantly reduces material cost and improves toughness, directly resolving the contradiction between flexibility and strength.
5Ease of manufacture
If paper is used as substrate material, then OLED devices achieve low cost and wide material availability, but the paper lacks toughness and has high water- and oxygen-permeabilities
Solution Approach 1:
The patent uses PET/PVDC/acrylic composite film substrate that maintains the low cost advantage while providing excellent toughness and water/oxygen barrier properties. The composite structure with PVDC barrier layer specifically addresses the permeability issue, while the overall film structure provides sufficient toughness, resolving the contradiction between cost and reliability.
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 provides a flexible, cost-effective, and impermeable substrate that significantly improves the water and oxygen barrier properties of paper, making it suitable for OLED devices with enhanced durability and stability, suitable for commercial applications.
Implementation Method 1
bonding the two heat-sealable films, i.e. the first and second protective layers, with the paper layer by a heat-sealing process
Implementation Method 2
the buffer layer may be a hardened buffer layer produced by coating with UV curable resin
Implementation Method 3
placing in a vacuum oven at a temperature of 40° C. and a vacuum degree of 0.01 MPa, and drying for 10-20 hours, to remove residual water in the paper
Data Source
AI summary
A substrate, manufacturing method thereof, and an organic electroluminescent device using the same are provided, belonging to photoelectron field. The substrate includes a paper layer (102), a first protection layer (101) formed on the lower surface of the paper layer, and a second protection layer (103) formed on the upper surface and covering the same of the paper layer. The substrate, solves problems of paper which is easy to absorb humidity and has high permeability of oxygen by a protection processing that said paper is coated with the heat seal film of polyethylene terephthalate coated with Polyvinyl Dichloride. At the meantime, the substrate has the advantages of cheap material, extensive sources, simple manufacturing process, good flexibility of the substrate, and good capability of preventing the permeability of water as well.