OLED Inversion Resolves Cathode Resistance and Light Transmittance Trade-off
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Solution Overview
Problem
OLED devices face reduced luminous efficiency due to the low transmittance of metal cathodes, which increases surface resistance and driving voltage when thinned to minimize obstruction, leading to higher energy consumption.
Innovation Solution
An electroluminescent device with a transparent anode layer on the light exit side, comprising a metal cathode layer, electron transport layer, emitting layer, and hole transport layer, along with optional transparent conductive and buffer layers, allowing light emission from the transparent anode layer and enabling thicker metal cathode layers to reduce surface resistance and driving voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the thickness of the metal cathode is reduced to improve light transmittance, then the light obstruction is minimized, but the surface resistance increases significantly leading to higher driving voltage and energy consumption
Solution Approach 1:
The patent inverts the conventional OLED light emission direction by placing the transparent anode on the light exit side and the metal cathode on the opposite side. This allows light to exit through the transparent anode rather than the metal cathode, enabling the metal cathode to be made thicker without compromising light transmittance. The inversion resolves the contradiction by decoupling the light emission function from the metal cathode, allowing it to be optimized for electrical conductivity with increased thickness and reduced surface resistance.
2Loss of energy
If the thickness of the metal cathode is reduced to improve light transmittance, then the overall luminous efficiency is improved, but the surface resistance increases leading to higher driving voltage
Solution Approach 1:
The patent inverts the conventional OLED structure by placing the transparent anode on the light exit side and the metal cathode on the opposite side. This structural inversion allows the metal cathode to be made thicker to reduce surface resistance and driving voltage, while light still exits efficiently through the transparent anode. The inversion resolves the contradiction by separating the light emission function from the metal cathode, allowing simultaneous optimization of both luminous efficiency and electrical conductivity.
Solution Approach 2:
The transparent anode acts as an intermediary that performs the light emission function, allowing the metal cathode to focus on electrical conductivity. By introducing this intermediary layer, the patent enables the metal cathode to be thicker without negatively impacting light transmittance or luminous efficiency, while simultaneously reducing surface resistance and driving voltage.
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 overall luminous efficiency and reduces energy consumption by avoiding light obstruction and increasing the thickness of the metal cathode layer, while maintaining a good display effect and minimizing viewing angle defects.
Implementation Method 1
When an electric field more than a certain threshold is applied on the anode 040 and the cathode 020, holes and electrons enter the light emitting layer of the functional layer 030 respectively from the anode 040 and cathode 020; then the radiative recombination causes luminescence
Data Source
AI summary
The embodiments of the present invention provide an electroluminescent device and manufacturing method thereof, display substrate and display device, which relate to the field of display technology. The overall luminous efficiency of the OLED device is improved without reducing the thickness of the metal cathode, ensuring a good display effect of the OLED device. The electroluminescent device comprises a metal cathode layer, a functional layer and a transparent anode layer arranged on a basal substrate; the transparent anode layer is located on the light exit side of the electroluminescent device; the functional layer is located between the metal cathode layer and the transparent anode layer; the functional layer comprises an electron transport layer, an emitting layer and a hole transport layer sequentially arranged from the metal cathode layer.