OLED Gas Barrier Layer Width Variation for Crack Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic electroluminescence devices face issues with moisture and oxygen ingress, leading to degradation and the formation of non-emission regions, which reduces their lifespan and efficiency, particularly due to the challenges in forming a flat and crack-free gas barrier layer around the peripheral edges.
Innovation Solution
The solution involves forming a gas barrier layer wider than the organic buffer layer, with a peripheral seal layer composed of ultraviolet curable resin that increases in viscosity during bonding, and an adhesive layer made of thermosetting resin to reinforce the gas barrier and prevent moisture ingress, while spherical particles control the distance between substrates for efficient light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the gas barrier layer is formed directly on an element substrate including a pixel partition, then cracks occur due to the irregular surface shape, but forming a buffer layer increases device complexity
Solution Approach 1:
An organic buffer layer is introduced as an intermediary between the element substrate and the gas barrier layer. This buffer layer fills in the irregularities of the pixel partition structure, providing a flat surface for the gas barrier layer while preventing direct contact that would cause cracking. The buffer layer acts as a stress-absorbing intermediate structure.
Solution Approach 2:
The organic buffer layer is formed beforehand to cushion and distribute the stress that would otherwise concentrate at the irregular interfaces between the gas barrier layer and pixel partitions. This pre-cushioning prevents crack formation during subsequent processing and operation.
2Area of stationary object
If the frame portion is narrowed to maximize light emission area, then the gas barrier layer becomes more susceptible to damage at peripheral edges, but maintaining a wide frame reduces active display area
Solution Approach 1:
The gas barrier layer is formed with different widths at different locations: it extends wider at the peripheral edges where stress concentration occurs, and can be narrower in the central light-emitting regions. This local variation in geometry provides enhanced protection at critical areas while maximizing the overall light emission area.
Solution Approach 2:
The problem is solved by transitioning from a uniform one-dimensional width specification to a two-dimensional variable width configuration. The gas barrier layer's width varies as a function of position, particularly increasing at peripheral regions, thereby providing localized reinforcement without compromising the overall active area.
3Object-generated harmful factors
If a light shielding layer is added to prevent light leakage in narrowed frame portions, then ultraviolet light for curing cannot reach the peripheral seal layer, but without it light leakage occurs
Solution Approach 1:
The peripheral seal layer is cured with ultraviolet light before the light shielding layer is formed. This preliminary curing action ensures that the seal layer is already solidified and functional before the shielding layer is applied, eliminating the need for subsequent UV transmission through the shielding layer.
Solution Approach 2:
The curing process is divided into distinct stages: first, UV curing of the peripheral seal layer; second, formation of the light shielding layer. This periodic separation of functions allows each layer to be optimized for its specific purpose without interfering with the other's performance.
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 approach effectively prevents damage to the gas barrier layer, reduces non-emission regions, enhances the design flexibility of devices, and improves the adhesion and heat resistance of the organic electroluminescence device, leading to improved durability and efficiency.
Implementation Method 1
the viscosity may be increased by ultraviolet irradiation before bonding of the element substrate and the sealing substrate
Implementation Method 2
a transparent thin film of silicon nitride, silicon oxide, or ceramic, which has excellent gas barrier performance, is deposited as a gas barrier layer
Implementation Method 3
an organic buffer layer is formed on the cement substrate, and then the gas barrier layer is formed thereon
Data Source
AI summary
An organic electroluminescence device includes an element substrate including a plurality of light-emitting elements each having an organic luminescent layer held between a pair of electrodes, a sealing substrate opposed to the element substrate, and a peripheral seal layer provided in the peripheral portion between the element substrate and the sealing substrate, for fixing the element substrate and the sealing substrate, wherein an electrode protecting layer covering the light-emitting elements, an organic buffer layer covering the electrode protecting layer, and a gas barrier layer covering the organic buffer layer are formed, the gas barrier layer is formed in a region wider than that of the organic buffer layer, the peripheral seal layer is provided on the gas barrier layer, and the peripheral edge of the organic buffer layer is disposed within the width of the peripheral seal layer