Multi-Layer Light-Emitting Element for Efficient Color Emission
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Solution Overview
Problem
Current light-emitting elements for display devices face challenges in achieving high emission efficiency, low power consumption, and cost-effective manufacturing, particularly in the separate coloring method, which requires precise alignment and results in low yield and high manufacturing costs, while the color filter method has low light use efficiency due to shared light-emitting layers.
Innovation Solution
A light-emitting element with multiple light-emitting layers, where carrier recombination regions are adjusted using different injection layers to control the colors of light emitted, allowing for a simpler layer structure and improved light extraction efficiency, reducing the need for precise alignment and shared light-emitting layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the separate coloring method is used with multiple EL layers, then different colors can be emitted from different subpixels, but manufacturing precision and yield deteriorate due to the need for precise alignment of shadow masks
Solution Approach 1:
The patent merges multiple light-emitting layers into a single integrated EL layer structure, eliminating the need for separate shadow mask alignment for each layer. The single EL layer contains multiple light-emitting substances that can emit different colors, combining the functionality of multiple layers while simplifying the manufacturing process and improving yield.
Solution Approach 2:
The patent creates a universal EL layer structure that can emit multiple colors simultaneously or selectively. By incorporating multiple light-emitting substances with different emission characteristics into a single layer, the structure performs multiple color emission functions without requiring separate processing steps for each color, thereby improving manufacturing precision and yield.
2Productivity
If the color filter method is used with a shared EL layer, then manufacturing cost is reduced and productivity increases, but light use efficiency deteriorates
Solution Approach 1:
The patent applies local quality by creating regions within the single EL layer that have different light-emitting characteristics. Different areas of the EL layer contain light-emitting substances optimized for specific color emissions, allowing each region to efficiently emit its designated color without relying on color filters, thereby improving light use efficiency while maintaining the manufacturing advantages of a shared layer structure.
3Power
If multiple EL layers are stacked to achieve white light emission, then emission efficiency can be improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines multiple light-emitting layers into a single EL layer that contains multiple light-emitting substances. This merging approach maintains the emission efficiency benefits of having multiple light-emitting materials while eliminating the complexity of stacking multiple separate layers, reducing device complexity and manufacturing cost.
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 approach enhances emission efficiency, reduces manufacturing complexity and costs, and improves light use efficiency by allowing for balanced light emission from multiple layers, addressing the limitations of both separate coloring and color filter methods.
Implementation Method 1
research and development have been extensively conducted on light-emitting elements using electroluminescence (EL). By applying a voltage between the pair of electrodes of this element, light emission from the light-emitting substance can be obtained.
Implementation Method 2
a method has been proposed, in which a micro optical resonator (microcavity) structure utilizing a resonant effect of light between a pair of electrodes is used to increase the intensity of light having a specific wavelength
Data Source
AI summary
A light-emitting element with high emission efficiency which includes a plurality of light-emitting layers and exhibits multi-color light emission is provided. The light-emitting element includes a first electrode, a second electrode, and an EL layer between the first electrode and the second electrode. The EL layer includes a first injection layer, a first light-emitting layer, and a second light-emitting layer in a first region, and a second injection layer, the first light-emitting layer, and the second light-emitting layer in a second region. The first light-emitting layer includes a first light-emitting material and a first host material, and the second light-emitting layer includes a second light-emitting material and a second host material. A color of light emitted from the first region is different from that of light emitted from the second region.