Organic Electroluminescent Device with Graded Insulator Density
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Solution Overview
Problem
Organic electroluminescent devices face challenges in achieving uniform luminance due to voltage drops as the distance from the electrode terminal increases, leading to non-uniform emission intensity, and existing solutions complicate the device structure and production.
Innovation Solution
A functional device with a pair of electrodes and an insulator layer where the insulator density decreases with distance from the terminal, forming a discontinuous phase, and an electroconductive material forms a continuous phase, or electrodes with notch sections whose area ratio decreases with distance, to compensate for voltage drops and ensure uniform current density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the distance from the electrode terminal increases, then the voltage drop increases, but the emission intensity becomes lower and uniform luminance cannot be obtained
Solution Approach 1:
The insulator density is varied locally across the device - higher density near the terminal and lower density farther away. This spatial variation in insulator properties compensates for the voltage drop gradient, maintaining uniform current density and emission intensity across the entire device surface.
Solution Approach 2:
The density parameter of the insulator is changed as a function of position from the terminal. By gradually decreasing the insulator density with increasing distance from the terminal, the electrical characteristics are adjusted to compensate for voltage drops, achieving uniform luminance output.
2Illumination intensity
If attempts are made to compensate for voltage drop by increasing organic layer thickness or adding auxiliary wiring, then emission intensity can be enhanced, but the device structure becomes complicated
Solution Approach 1:
Instead of adding structural elements, the invention changes the physical parameter (density) of an existing component (insulator) as a function of position. This achieves compensation for voltage drop and uniform emission enhancement without complicating the device structure.
Solution Approach 2:
The invention uses a simplified approach by modifying the insulator density profile rather than copying complex compensation structures like auxiliary wiring. This creates a more manufacturable solution that achieves the same functional effect with simpler structure.
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
The solution achieves uniform in-plane output and emission intensity across the device surface, improving production suitability and reducing luminance unevenness, while maintaining a simpler and more productive device structure.
Implementation Method 1
an insulator is arranged between the electrodes and the density of the insulator becomes gradually decreases as the distance from the terminal increase
Implementation Method 2
a thin film material which receives the supply of an electric current so as to be excited, thereby emitting light
Data Source
AI summary
A functional device having, on a substrate, a pair of electrodes, a functional layer which is sandwiched between the electrodes and has an output that varies in accordance with an applied electric current, and a terminal arranged to apply an electric current to at least one of the electrodes, wherein an insulator is arranged between the electrodes and the density of the insulator decreases as the distance from the terminal increases, or wherein at least one of the electrodes has a notch section, and the ratio of the area of the notch section to the area of the electrode decreases as the distance from the terminal increases. This is an improved functional device which is excellent in production suitability and gives a uniform in-plane output, and can be rendered, in particular, an organic electroluminescence device.