Organic Electroluminescent Element Wide-Angle Color Rendering
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Solution Overview
Problem
Conventional organic electroluminescent elements do not maintain high color rendering properties across a wide angle region, limiting their versatility in lighting applications.
Innovation Solution
An organic electroluminescent element with a structure comprising electrodes and an organic light-emitting layer containing three luminescent materials with specific wavelength ranges (430 nm to 480 nm, 510 nm to 610 nm, and 580 nm to 630 nm) is designed, where the second and third light-emitting layers have a refractive index and dimension relationship that enhances light emission across a wide angle, ensuring higher average color rendering indexes from 30° to 60° compared to the front direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional organic electroluminescent elements are used, then the device structure is simple, but the color rendering property deteriorates in wide angle regions
Solution Approach 1:
The organic light-emitting layer is divided into multiple light-emitting layers, each containing luminescent materials with different maximum light emission wavelengths (430-480 nm, 510-610 nm, and 580-630 nm). This segmentation allows each layer to contribute to different color ranges, achieving high color rendering properties across wide angle regions while maintaining overall device functionality
Solution Approach 2:
Different light-emitting layers are positioned at specific locations within the device structure, with each layer having optimized local properties (refractive index, thickness, luminescent material composition) to enhance light emission in specific wavelength ranges. The second and third light-emitting layers are specifically designed with refractive index and dimension relationships to optimize wide-angle color rendering
2Illumination intensity
If the light emission is optimized for front direction, then the brightness in front direction is high, but the color rendering property deteriorates in wide angle region of 30° to 60°
Solution Approach 1:
The invention transitions from optimizing light emission in a single direction (front direction) to optimizing emission across multiple angular dimensions. By designing the light-emitting layers with specific refractive index relationships and thicknesses, the device achieves enhanced color rendering properties that maintain high performance across a wide angular range (30° to 60°) rather than being confined to the front direction only
Solution Approach 2:
The refractive index and thickness parameters of the second and third light-emitting layers are specifically optimized to satisfy the relationship (n3×d3)/λ3≧(n2×d2)/λ2, with (n2×d2)/λ2 in the range of 0.15 to 0.3. This parameter optimization enables the device to achieve high average color rendering indexes in wide angle regions while maintaining angular distribution versatility
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 provides an organic electroluminescent element with high color rendering properties across a wide angle region, effectively addressing the limitations of conventional elements by increasing the average color rendering indexes in the specified angle range, enhancing illumination effectiveness for various applications.
Implementation Method 1
Organic electroluminescent element includes electrodes and an organic light-emitting layer that is between the electrodes
Implementation Method 2
The luminescent materials are first, second and third luminescent materials. The first luminescent material has a maximum light emission wavelength within a range of 430 nm to 480 nm
Implementation Method 3
the organic electroluminescent element includes, as the electrodes, a reflection electrode and a transparent electrode
Data Source
AI summary
An organic electroluminescent element includes electrodes and organic light-emitting layers that are between the electrodes. The organic light-emitting layers contain at least three colors of luminescent materials. A first luminescent material has a maximum light emission wavelength within a range of 430 nm to 480 nm. A second luminescent material has a maximum light emission wavelength within a range of 510 nm to 610 nm. A third luminescent material has a maximum light emission wavelength within a range of 580 nm to 630 nm. An average value of average color rendering indexes in a wide angle region of 30° to 60° with respect to a front direction of a light emission surface is higher than an average color rendering index in the front direction.