OLED Reflective Layer Optimization for Single-Mask Deposition
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Solution Overview
Problem
Existing organic light emitting diode (OLED) displays face challenges in improving light emission efficiency without increasing the number of masks used for depositing the organic layer, which affects manufacturing time and costs, especially when emitting lights of different wavelengths.
Innovation Solution
The OLED display employs a configuration where organic light emitting elements with different wavelengths, such as blue, green, and red, utilize reflective layers made of distinct metals like silver and aluminum, optimized for constructive interference, allowing for simultaneous deposition of organic layers using a single mask, thereby enhancing light emission efficiency and reducing manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different masks are used for depositing organic layers for different wavelengths, then light emission efficiency is improved, but manufacturing complexity and time increase
Solution Approach 1:
The patent applies local quality by using a single mask for all organic layer depositions, but optimizing the reflective layer properties (material composition, thickness) locally for each wavelength region. The reflective layer is designed with specific metal compositions (e.g., Ag for blue, Al for red) and thicknesses that create constructive interference for respective wavelengths, compensating for the lack of separate masks through localized optical property tuning.
2Reliability
If more masks are used for depositing organic layers for different wavelengths, then light emission efficiency is improved, but manufacturing time increases
Solution Approach 1:
The patent merges multiple mask-based deposition processes into a single mask process. By combining the functions of multiple masks into one universal mask design, and compensating through reflective layer optimization, the manufacturing process is simplified and accelerated while maintaining wavelength-specific light emission efficiency.
Solution Approach 2:
The reflective layer is designed in advance with predetermined material compositions and thicknesses that are optimized for constructive interference at specific wavelengths. This preliminary optimization of the reflective layer properties allows a single mask to achieve wavelength-specific efficiency without requiring subsequent adjustments or additional masking steps.
3Productivity
If a single mask is used for depositing organic layers for different wavelengths, then manufacturing time is reduced, but light emission efficiency may deteriorate
Solution Approach 1:
The patent changes the parameters of the reflective layer (material composition, thickness, optical properties) to optimize light emission efficiency for different wavelengths. By adjusting these parameters, the system achieves wavelength-specific constructive interference using a single mask, thereby maintaining high light emission efficiency while benefiting from simplified manufacturing.
Solution Approach 2:
The reflective layer uses composite material structures with specific metal compositions (e.g., Ag, Al, and their alloys) that are tailored for different wavelength regions. These composite reflective structures provide enhanced optical performance for single-mask deposition by creating favorable interference conditions for respective wavelengths through material composition optimization.
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 configuration enhances light emission efficiency for each wavelength while reducing manufacturing time and costs by allowing the same organic light emitting layers to be deposited using a single mask, improving the overall performance and efficiency of the OLED display.
Implementation Method 1
a first reflective layer RL1 including a first metal material and a second reflective layer RL2 including a second metal material different from the first metal material, respectively, in the first electrode E1
Implementation Method 2
optimized for constructive interference
Data Source
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AI summary
An organic light emitting diode display includes: a first organic light emitting element configured to emit light having a first wavelength; and a second organic light emitting element configured to emit light having a second wavelength substantially shorter than the first wavelength. The first organic light emitting element includes a first electrode, and the second organic light emitting element includes a second electrode having substantially higher reflectance for the light having the second wavelength than the first electrode.