Organic Light Emitting Device Resonator Structure
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Solution Overview
Problem
Existing organic light emitting devices with light resonator structures face challenges in improving luminescent performance and light extraction characteristics while maintaining low driving voltage and addressing view angle dependency, particularly due to limitations in anode materials and layer thicknesses.
Innovation Solution
The use of a lamination structure with a reflective cathode and a semi-transparent anode made of a metal thin film, where the light emitting layer is positioned on the resonant face close to the cathode, optimizing the resonator structure to enhance light extraction efficiency without increasing driving voltage and improving luminescent performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light resonator structure is used to improve color purity and light extraction efficiency, then the front optical power and color purity are improved, but the view angle dependency increases and the luminescent performance becomes insufficient
Solution Approach 1:
The patent transitions from a conventional bottom-emission structure to a top-emission structure with a light resonator. This dimensional change in light extraction direction enables the resonator to effectively enhance front optical power while the specific configuration (reflective cathode, semi-transparent anode, optimized layer thicknesses) mitigates view angle dependency by creating favorable optical paths.
Solution Approach 2:
The patent optimizes specific parameters of the light resonator structure including the thickness of the reflective cathode (50-200 nm), the organic layer (100-500 nm), and the semi-transparent anode (10-50 nm). These parameter adjustments fine-tune the resonator's optical properties to achieve high front optical power while reducing view angle dependency.
2Productivity
If the organic layer thickness is increased to improve luminescent performance, then the light extraction efficiency can be improved, but the driving voltage increases
Solution Approach 1:
The patent employs a top-emission structure with a light resonator that dynamically optimizes light extraction. The resonator configuration (reflective cathode, semi-transparent anode, and intermediate organic layer with specific thickness) creates constructive interference for extracted light, achieving high light extraction efficiency without requiring excessive organic layer thickness, thus avoiding high driving voltages.
3Illumination intensity
If a metal oxide conductor is used for the anode to ensure high light transmittance, then the light transmittance is improved, but the organic layer is largely damaged during deposition
Solution Approach 1:
The patent uses an ultra-thin semi-transparent anode with thickness of 10-50 nm. This thin film configuration achieves sufficient light transmittance while minimizing deposition damage to the organic layer. The reduced thickness allows for gentler deposition processes that preserve organic layer integrity.
Solution Approach 2:
The patent employs a composite anode structure combining a metal oxide conductor layer with an ultra-thin metal layer. This composite configuration provides both the required light transmittance and electrical conductivity while the thin metal component minimizes deposition damage to the organic layer.
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 achieves high light extraction efficiency, reduces view angle dependency, and enhances luminescent performance, making the display unit suitable for diverse active drive circuits like organic TFTs, while maintaining low power consumption.
Implementation Method 1
a resonator structure that resonates the light generated in the light emitting layer between the cathode and the anode
Implementation Method 2
the cathode is reflective and the anode is semi-transparent to light generated in the light emitting layer
Implementation Method 3
an organic EL (Electro Luminescence) phenomenon has been noted
Data Source
AI summary
An organic light emitting device capable of improving the light extraction characteristics while suppressing the driving voltage and improving the luminescent performance, and a display unit using it are provided. The organic light emitting device includes: a lamination structure that includes a cathode, a plurality of layers including a light emitting layer made of an organic material, and an anode including a metal thin film in this order, in which the cathode is reflective and the anode is semi-transparent to light generated in the light emitting layer; and a resonator structure that resonates the light generated in the light emitting layer between the cathode and the anode.