Blue OLED Light Extraction Member for Luminous Efficiency
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Solution Overview
Problem
The low exciton utilization rate of blue fluorescent materials in OLED display apparatuses leads to low luminous efficiency and increased operating load, causing adjacent light-emitting devices to inadvertently light up, affecting color display quality.
Innovation Solution
A top-emission light-emitting substrate with a blue light-emitting device structure that includes a first and second light enhancement layer with specific refractive index layers and a light extraction member, optimized to enhance light emission and reduce operating load by confining excitons, using materials with controlled electron and hole mobility ratios and energy levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blue fluorescent material is used in the blue light-emitting device, then stability is improved, but luminous efficiency deteriorates due to low exciton utilization rate
Solution Approach 1:
The patent changes the refractive index parameter by introducing a light extraction member with refractive index higher than surrounding layers. This parameter change enables better light extraction efficiency from the blue light-emitting device, thereby improving luminous efficiency while maintaining the stability advantage of blue fluorescent materials.
2Illumination intensity
If operating load is increased to improve luminous efficiency, then light emission is enhanced, but adjacent light-emitting devices inadvertently light up
Solution Approach 1:
The patent applies local quality by placing a light extraction member with specific high refractive index properties at the local position of the blue light-emitting device. This localized intervention enhances light extraction only from the blue device without affecting adjacent red and green devices, thus improving light emission while preventing adjacent device interference.
3Productivity
If light extraction member with wavelength-matched transmittance is added, then luminous efficiency is improved, but device structure becomes more complex
Solution Approach 1:
The light extraction member serves multiple functions: it extracts light from the blue light-emitting device, blocks leakage current to adjacent devices, and can be integrated with the existing encapsulation structure. This multi-functionality improves luminous efficiency while minimizing the increase in device complexity.
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 significantly improves luminous efficiency and extends the service life of blue light-emitting devices, reducing the likelihood of adjacent devices lighting up, thereby enhancing the color display effect.
Implementation Method 1
A wavelength corresponding to a transmittance peak of the light extraction member and a wavelength corresponding to an emission spectrum peak of the blue light-emitting device, an absolute value of a difference therebetween is less than or equal to 10 nm
Implementation Method 2
The second light enhancement layer includes a first inorganic layer, an organic layer and a second inorganic layer that are sequentially stacked. Refractive index of the organic layer is less than refractive index of the first inorganic layer and less than refractive index of the second inorganic layer
Data Source
AI summary
A light-emitting substrate includes a base substrate, a light-emitting unit and a light extraction member arranged in sequence. The light-emitting unit includes at least one blue light-emitting device, a first light enhancement layer and a second light enhancement layer arranged in sequence. A blue light-emitting device includes a first electrode, at least one blue light-emitting layer and a second electrode sequentially stacked. An orthographic projection of the light extraction member on the base substrate at least partially overlaps with an orthographic projection of the blue light-emitting device on the base substrate. An absolute value of a difference between a wavelength corresponding to a transmittance peak of the light extraction member and a wavelength corresponding to an emission spectrum peak of the blue light-emitting device is less than or equal to 10 nm.