Light Scattering Layer for Plane Emission Devices
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Solution Overview
Problem
Organic electroluminescence (EL) devices suffer from low takeout efficiency due to total reflection of light at the boundary faces between the transparent substrate and air, and the transparent electrode layer and substrate, resulting in significant light loss.
Innovation Solution
A plane emission device is designed with a light scattering layer on the transparent substrate, containing a binder and two kinds of fillers with specific refractive index relationships (Nf2 > Nb > Nf1), which increases the scattering effect and reduces total reflection, enhancing light exit efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a light scattering layer is formed on the transparent substrate to improve light takeout efficiency, then the takeout efficiency of light is improved, but the device structure becomes more complex
Solution Approach 1:
The light scattering layer is constructed as a composite material containing a binder and two kinds of fillers with different refractive indices (Nf2 > Nb > Nf1). This composite structure enhances light scattering efficiency by creating multiple refractive index boundaries, thereby improving light takeout efficiency while managing the structural complexity through material composition rather than layered complexity.
2Loss of energy
If two kinds of fillers with different refractive indices are used in the light scattering layer to increase scattering effect, then the incident efficiency into the transparent substrate is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The invention utilizes parameter changes by selecting fillers with different refractive indices (Nf2 > Nb > Nf1) to optimize light scattering. The specific refractive index values are chosen to create optimal scattering conditions at the boundaries between layers, improving incident efficiency while the parameters are controlled within practical manufacturing ranges.
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 configuration significantly improves the takeout efficiency of light by disordering critical angles and increasing incident efficiency into the transparent substrate, leading to higher luminance and luminous efficiency.
Implementation Method 1
a light scattering layer formed on a surface of the transparent substrate, wherein the light scattering layer contains a binder and two kinds of fillers
Implementation Method 2
total reflection on the boundary face between the transparent substrate and air, total reflection on the boundary face between the transparent electrode layer and the transparent substrate
Implementation Method 3
exit angles of the lights emitted from the luminescent layer which is thin film of a luminous body are defined by refraction index of the luminescent layer and refraction indexes of media into which the emitted lights pass through
Data Source
AI summary
In a plane emission device comprising a transparent substrate, a light scattering layer formed on a surface of the transparent substrate, and a luminescent body of organic or inorganic material which is formed on a surface of the light scattering layer and emits light by light or electric energy, efficiency to takeout light to outside is improved. The light scattering layer contains binder and two kinds of fillers, and when a refraction index of the binder is assumed as Nb, a refraction index of one of the two kinds of fillers is assumed as Nf1, and a refraction index of the other is assumed as Nf2, a relationship that Nf2>Nb>Nf1 is satisfied. Since the light scattering layer contains two kinds of fillers, disorder occurs in critical angle when light exits from the light scattering layer to the transparent substrate, incidence rate of light into the transparent substrate rises, and efficiency to takeout the light to outside increases.