OLED Display Silver Cathode Thickness Optimization
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Solution Overview
Problem
Existing organic light emitting diode (OLED) displays face inefficiencies in light emission due to suboptimal thickness and material properties of the emission layer and second layer, particularly when using aluminum cathodes, which affect light efficiency and require separate adjustment factors for different colors.
Innovation Solution
The OLED display employs a structure where the thickness of the emission layer and the second layer is optimized using the equation d=λ^4*k-α, with α varying by emission color, and utilizing a silver or silver alloy cathode, which allows for adjusted thicknesses of 700 Å or less for red, 600 Å or less for green, and 460 Å or less for blue, improving light efficiency by aligning with the emission wavelength and absorption coefficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the thickness of the emission layer and second layer is increased to improve light output, then light efficiency improves, but the device complexity and manufacturing precision requirements increase due to the need for separate adjustment factors for different colors
Solution Approach 1:
The patent changes the thickness parameter of the emission layer and second layer according to a specific mathematical relationship (d=λ/4k) that accounts for different emission wavelengths. This single universal formula replaces the need for multiple separate adjustment factors for different colors, simplifying the device while maintaining optimal light efficiency across all emission colors.
2Ease of manufacture
If aluminum cathodes are used in the OLED display, then manufacturing is easier, but light efficiency decreases requiring separate adjustment factors for different colors
Solution Approach 1:
The patent changes the cathode material parameter from aluminum to silver or silver alloy. This material substitution fundamentally improves light efficiency by reducing parasitic absorption and improving electron injection, eliminating the need for separate adjustment factors while maintaining ease of manufacture through established silver deposition processes.
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 emitting efficiency by optimizing the thickness and material properties of the emission and second layers, particularly with silver alloy cathodes, outperforming displays with aluminum cathodes in terms of light output and reducing the need for separate adjustment factors across different colors.
Implementation Method 1
If a voltage is applied between the first electrode and the second electrode, the holes are injected into the emission layer through the incidental layer assisting with injection and/or transferring of the holes from the first electrode, and the electrons are injected into the emission layer through the incidental layer assisting with injection and/or transferring of the electrons from the second electrode. The holes and the electrons injected into the emission layer are recombined in the emission layer to generate excitons, and light is emitted while the excitons are transferred from an excited state to a lower or ground state.
Implementation Method 2
a thickness d of the emission layer and the second layer satisfies the following d=λ^4*k-α where, λ is a light wavelength, k is an absorption coefficient
Data Source
AI summary
An organic light emitting diode display including a substrate, a thin film transistor on the substrate, a first electrode connected to the thin film transistor, a first layer on the first electrode, an emission layer on the first layer, a second layer on the emission layer, and a second electrode on the second layer.