Light Emitting Device Vacuum Substrate Attachment
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Solution Overview
Problem
Conventional light emitting devices with organic EL elements face issues of moisture penetration, leading to reduced luminance and shortened lifespan due to the use of atmospheric pressure during substrate attachment, which causes bending and cracking of substrates and reduces adhesiveness.
Innovation Solution
The solution involves attaching substrates with a light emitting element under reduced pressure, using columnar or wall-shaped structures to maintain a precise gap and disperse pressure, and filling the sealed space with a filler having a refractive index difference of 0 to 0.7 with the substrates to enhance light extraction efficiency and prevent substrate bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If substrates are attached under atmospheric pressure, then the attachment process is simple, but the substrates bend and crack and adhesiveness is reduced
Solution Approach 1:
The patent changes the pressure parameter from atmospheric pressure to reduced pressure (vacuum) during the substrate attachment process. This parameter change prevents substrate bending and cracking while maintaining good adhesiveness, resolving the contradiction between manufacturing simplicity and product reliability.
2Reliability
If substrates are attached under reduced pressure, then substrate bending and cracking are prevented, but the attachment process becomes more complex
Solution Approach 1:
The patent uses the vacuum environment to serve multiple functions simultaneously: it prevents substrate bending and cracking during attachment, and also removes moisture from the sealed space. This self-service approach reduces the need for additional complex processes, mitigating the increase in device complexity.
3Stability of the object's composition
If the sealed space is kept under positive pressure, then the substrates remain flat, but moisture penetration occurs and device lifespan is shortened
Solution Approach 1:
The patent creates a vacuum (inert) environment in the sealed space to prevent moisture penetration. The vacuum atmosphere acts as a barrier against moisture, protecting the light emitting element and extending device lifespan, while resolving the contradiction between maintaining substrate flatness and preventing moisture damage.
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 moisture ingress, maintains substrate integrity, and improves light extraction efficiency by maintaining a constant gap and reducing pressure-induced substrate bending, resulting in enhanced display performance and longer device lifespan.
Implementation Method 1
a sealed space surrounded by a sealing material with a closed pattern is kept under negative pressure
Implementation Method 2
the pressure applying to the substrates is dispersed, thereby preventing bending and cracking of the substrates
Implementation Method 3
the angle of refraction is varied with location
Data Source
AI summary
To provide a light emitting device that has a structure in which a light emitting element is sandwiched by two substrates to prevent moisture from penetrating into the light emitting element, and a method for manufacturing thereof. In addition, a gap between the two substrates can be controlled precisely. In the light emitting device according to the present invention, an airtight space surrounded by a sealing material with a closed pattern is kept under reduced pressure by attaching the pair of substrates under reduced pressure. A columnar or wall-shaped structure is formed between light emitting regions inside of the sealing material, in a region overlapping with the sealing material, or in a region outside of the sealing material so that the gap between the pair of substrates can be maintained precisely.