Flexible Electroluminescent Device with Segmented Base for Heat Dissipation
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Solution Overview
Problem
Conventional organic EL display devices face issues with heat accumulation and damage due to repetitive bending, as well as difficulties in reducing base thickness and minimizing bending stress, leading to separation or twisting of layers and damage to the organic EL element and sealing layer.
Innovation Solution
An electroluminescent device with a flexible base and an adjustment layer having heat dissipating properties, positioned on the electroluminescent element side relative to the center of the device, to adjust the neutral surface and dissipate heat efficiently, using materials like carbon materials or carbon-dispersed organic resins with high heat conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base is made thick to adjust the neutral surface and minimize bending stress, then the bendability and protection of the organic EL element are improved, but heat accumulates inside the device causing separation of films and twisting of the base
Solution Approach 1:
The base is divided into a first base portion and a second base portion with different thicknesses. The first base portion (with organic EL element) has smaller thickness to reduce heat accumulation, while the second base portion has larger thickness to maintain neutral surface adjustment and bending stress minimization. This segmentation allows simultaneous optimization of heat dissipation and mechanical protection.
Solution Approach 2:
Different regions of the base have different thickness properties tailored to local requirements. The region under the organic EL element uses thinner material for heat dissipation, while other regions use thicker material for structural support and neutral surface control. This local differentiation resolves the contradiction between heat accumulation and protection.
2Reliability
If the base is made thick to adjust the neutral surface, then the bending stress on the organic EL element is minimized, but the device cannot be adequately thinned and heat dissipation is insufficient
Solution Approach 1:
The base is segmented into different thickness zones: a thinner first base portion for heat dissipation and a thicker second base portion for neutral surface adjustment. This allows the overall device to be thinner while maintaining adequate bending stress protection through the thicker second portion.
Solution Approach 2:
The base thickness is optimized in the vertical dimension by creating a non-uniform thickness profile. The first base portion has reduced thickness for heat dissipation, while the second base portion maintains sufficient thickness for mechanical function, achieving thinning in critical areas without compromising overall structural requirements.
3Temperature
If heat dissipating layers are filled into through holes in a plastic substrate, then local heat accumulation is controlled, but the base becomes thick and difficult to thin, and heat still accumulates in portions without heat dissipating layers
Solution Approach 1:
Instead of adding heat dissipating layers into through holes (which increases thickness), the invention segments the base itself into different thickness portions. The first base portion is made thin from the outset to enable heat dissipation, eliminating the need for additional heat dissipating layers and through holes in that region.
Solution Approach 2:
The heat dissipation function is extracted from the traditional approach of adding heat dissipating layers into through holes, and instead is achieved by making the first base portion itself thin. This removes the need for through holes and embedded heat dissipating layers, reducing overall base thickness.
4Temperature
If a metal substrate is used as the base to improve heat dissipating properties, then heat is dissipated efficiently, but the device loses flexibility and bendability
Solution Approach 1:
The first base portion uses a thin flexible structure for heat dissipation and bendability, while the second base portion maintains sufficient thickness for structural support. This local differentiation allows the device to achieve both heat dissipation efficiency and bendability without requiring a metal substrate throughout.
Solution Approach 2:
The first base portion is designed as a thin flexible film or shell structure that provides both heat dissipation pathways and the necessary bendability. This replaces the need for a rigid metal substrate while maintaining heat dissipation efficiency through the thin flexible structure.
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
Prevents heat accumulation inside the device, reduces damage from repetitive bending, and allows for a thinner device configuration while maintaining effective heat dissipation and improved bendability and sealing properties.
Implementation Method 1
an adjustment layer (15) having heat dissipating properties
Implementation Method 2
adjusts a neutral surface of the organic EL display device. The adjustment layer is provided on the organic EL element side relative to the center of the whole organic EL display device in a film thickness direction
Data Source
AI summary
An organic EL display device includes a flexible base and an organic EL element (electroluminescent element) provided on the base, and further includes an adjustment layer that has heat dissipating properties and that adjusts a neutral surface of the organic EL display device. The adjustment layer is provided on the organic EL element side relative to the center of the whole organic EL display device in the film thickness direction.