OLED Package Buffer Layer Stress Absorption
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Solution Overview
Problem
Conventional OLED packaging processes generate stress that can cause OLEDs to crack, reducing their lifespan due to the transfer of stress from the encapsulation layer to the OLED die.
Innovation Solution
The OLED package design includes a flexible substrate, a barrier layer, a TFT array, a protecting layer, and a multi-layered encapsulation layer with a buffer layer to absorb stress, ensuring the encapsulation layer does not directly transmit stress to the OLED die, and using specific materials like aluminum oxide and silicon dioxide to enhance protection and light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an encapsulation layer is deposited on the OLED die to protect it from environmental factors, then the protection against oxygen and moisture is improved, but stress is transferred to the OLED die causing cracks and reducing lifespan
Solution Approach 1:
A buffer layer is introduced as an intermediary between the encapsulation layer and the OLED die. This buffer layer absorbs the stress generated during encapsulation deposition, preventing direct stress transfer to the OLED die while maintaining the protective function of the encapsulation layer against environmental factors.
Solution Approach 2:
The buffer layer is deposited beforehand to provide cushioning protection against the stress that will be generated during subsequent encapsulation layer deposition. This preemptive measure prevents stress-induced cracking before it occurs, allowing the encapsulation process to proceed safely.
2Ease of manufacture
If a conventional encapsulation layer is deposited directly on the OLED die, then the manufacturing process is simple, but the OLED die cracks due to stress transfer reducing its lifespan
Solution Approach 1:
The buffer layer serves as an intermediary component that maintains the simplicity of the manufacturing process while dramatically improving the lifespan of the OLED package. The additional deposition step is straightforward and does not complicate the overall manufacturing workflow.
Solution Approach 2:
By depositing the buffer layer beforehand, the manufacturing process remains simple and straightforward while the buffer layer provides necessary stress absorption to prevent cracking and extend the operational lifespan of the OLED package.
3Reliability
If the encapsulation layer is made thicker to provide better protection, then the protection against environmental factors is improved, but the stress on the OLED die increases causing more cracks
Solution Approach 1:
The buffer layer acts as a stress-absorbing intermediary that enables the use of thicker encapsulation layers for enhanced environmental protection without increasing the stress transmitted to the OLED die. The buffer layer captures the excess stress, allowing the encapsulation layer to be optimized for protection without compromising device integrity.
Solution Approach 2:
The buffer layer provides beforehand cushioning that allows the encapsulation layer to be made thicker for better environmental protection. The buffer layer absorbs the stress generated by the thicker encapsulation layer, preventing stress-induced cracking while maintaining enhanced protection capabilities.
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 design significantly improves the stability and longevity of the OLED package by preventing damage from environmental factors and reducing the current required for operation, thereby extending the OLED's lifespan and enhancing light output.
Implementation Method 1
a buffer layer to absorb stress, ensuring the encapsulation layer does not directly transmit stress to the OLED die
Implementation Method 2
The barrier layer is arranged on the bottom surface of the substrate for preventing the moisture in the air from entering the OLED package
Implementation Method 3
a protecting layer arranged on the OLED die and covering side surfaces of the OLED die for protecting the OLED die from being destructed by stress
Implementation Method 4
OLEDs have many advantages, such as light weight, thin thickness, multiple colors and low manufacturing cost, compatibility with integrated circuits, easy driving, long term reliability, and environmental friendliness
Data Source
AI summary
An organic light emitting diode (OLED) package includes a substrate, an OLED die mounted on the substrate and an encapsulation layer encapsulating the OLED die. The OLED package further includes a protecting layer formed on the OLED die. The encapsulation layer has a multi-layered structure and is deposited on the protecting layer. Refractive indexes of a cathode of the OLED die, the protecting layer and the encapsulation layer are gradually decreased in the sequence. A barrier layer for blocking moisture from entering the OLED package is formed on a bottom surface of the substrate by atomic layer deposition (ALD) method. The present disclosure also provides a method for manufacturing the OLED package.