Thin Film Encapsulation Structure for OLED Moisture Barrier
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Solution Overview
Problem
Organic light emitting diodes (OLEDs) face shortening device life due to moisture and oxygen susceptibility, requiring effective encapsulation to isolate functional layers from the environment.
Innovation Solution
A thin film encapsulation structure comprising a mixing layer of amorphous aluminum oxide and crystalline oxide, with a SiNX inorganic layer, deposited using facing target and magnetron sputtering methods, providing a firm and compact protective film that effectively blocks moisture and oxygen, and serves as a buffer layer to reduce damage during deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional encapsulation methods are used to protect OLED devices from moisture and oxygen, then device reliability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent employs a composite thin film encapsulation structure consisting of alternating inorganic layers (Al2O3, SiO2, Si3N4) and organic layers (TPD, TCTA). This multi-material composite approach provides superior moisture and oxygen barrier properties compared to single-material encapsulation, while maintaining structural integrity and protection of the OLED device.
Solution Approach 2:
The encapsulation structure is divided into multiple discrete thin film layers with specific thicknesses (5-50 nm for inorganic layers, 10-100 nm for organic layers). Each layer serves a specific function: inorganic layers provide barrier properties, while organic layers provide flexibility and stress relief. This segmented structure achieves effective encapsulation without excessive complexity.
2Object-affected harmful factors
If thick encapsulation layers are used to block moisture and oxygen, then barrier performance is improved, but device weight and cost increase
Solution Approach 1:
The patent utilizes thin film encapsulation with inorganic layers ranging from 5-50 nm and organic layers from 10-100 nm. These ultra-thin films provide effective moisture and oxygen barrier properties through their layered composite structure, achieving high barrier performance without the weight penalty of thick encapsulation materials.
Solution Approach 2:
The patent optimizes the thickness parameters of each layer to achieve the desired barrier performance. By precisely controlling the thickness of inorganic layers (5-50 nm) and organic layers (10-100 nm), the structure achieves effective moisture and oxygen blocking while minimizing material usage and device weight.
3Reliability
If multiple deposition layers are deposited to improve encapsulation, then protective performance is improved, but manufacturing time and process complexity increase
Solution Approach 1:
The patent employs atomic layer deposition (ALD) and chemical vapor deposition (CVD) techniques that deposit thin films in a controlled, sequential manner. The inorganic layers are deposited first to establish the barrier structure, followed by organic layers that are pre-configured to provide complementary protection. This preliminary structuring optimizes the deposition process for subsequent mass production.
Solution Approach 2:
The patent replaces traditional mechanical or chemical encapsulation methods with physical vapor deposition techniques (ALD and CVD). These deposition methods allow for precise control of layer thickness and composition, enabling efficient manufacturing of multi-layer encapsulation structures without complex mechanical assembly or chemical processing steps.
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 encapsulation structure significantly prolongs the working life of OLED devices by reducing moisture and oxygen permeability, while being environmentally friendly and suitable for mass production, with reduced weight and cost.
Implementation Method 1
The facing target sputtering method is used in a sputtering equipment to sputter two kinds of target materials at the same time, so as to obtain the mixing layer thin film mainly composed of two kinds of materials of amorphous aluminum oxide and a crystalline oxide
Implementation Method 2
the magnetron sputtering method is used in the sputtering equipment to perform the inorganic layer thin film deposition
Data Source
AI summary
The present disclosure provides a thin film encapsulation structure for encapsulating a functional device on a substrate, including: a mixing layer thin film covering the functional device, and an inorganic layer thin film located above the mixing layer thin film, wherein the mixing layer thin film is mainly composed of amorphous aluminum oxide and a crystalline oxide. The present disclosure also provides an organic light emitting device, including a substrate, an OLED device located on the substrate, and the thin film encapsulation structure as mentioned above.