Multilayer Optical Film for OLED Brightness and Low Reflectivity
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Solution Overview
Problem
Conventional OLED displays suffer from low light-output efficiency and contrast due to internal reflection and polarization effects, with existing solutions either reducing brightness or complicating the manufacturing process.
Innovation Solution
A low-reflectivity, brightness-enhancing multilayer optical film comprising a transparent substrate with a light diffusion layer and a light-absorbing layer containing core-shell structured particles, which minimizes internal reflection and maximizes light transmission by scattering external light effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a circular polarizing plate is used to improve contrast, then contrast ratio increases, but light transmittance decreases to about 45%, degrading brightness
Solution Approach 1:
The optical film is divided into three functional layers: a light diffusion layer with spherical particles to scatter light, a light-absorbing layer with core-shell structured particles to absorb external light, and a transparent substrate. This segmentation allows each layer to perform its specific function without the need for a circular polarizing plate, thereby maintaining high brightness while achieving good contrast.
Solution Approach 2:
The patent uses composite materials including spherical particles (1-50 μm diameter) in the light diffusion layer and core-shell structured light-absorbing particles in the light-absorbing layer. The core-shell structure combines a light-absorbing core with a transparent resin shell, creating a composite material that effectively absorbs external light while allowing emitted light to pass through, replacing the need for polarizing materials.
2Reliability
If a light-absorbing layer is added to reduce external light entry, then contrast improves, but light-output efficiency decreases due to absorption of emitted light
Solution Approach 1:
The light-absorbing particles are positioned specifically in the light-absorbing layer between the light diffusion layer and the external environment. This local placement ensures that only external incident light is absorbed, while light emitted from the OLED and traveling toward the viewer passes through the transparent substrate without being absorbed, thus maintaining high light-output efficiency while improving contrast.
Solution Approach 2:
The patent converts the harmful effect of external light reflection (which degrades contrast) into a beneficial effect by using the light-absorbing layer to selectively absorb external light. The core-shell structured particles are designed to absorb external incident light while being transparent to emitted light, effectively converting the potential harm of light absorption into the benefit of improved contrast without sacrificing brightness.
3Illumination intensity
If multiple layers are added to reduce reflection and enhance brightness, then optical performance improves, but manufacturing complexity increases
Solution Approach 1:
The patent combines multiple functions into a single integrated optical film structure. The light diffusion layer, light-absorbing layer, and transparent substrate are combined into one component that simultaneously provides light diffusion, external light absorption, and brightness enhancement. This merging approach simplifies the overall device structure compared to using separate polarizing plates and anti-reflection coatings, reducing manufacturing complexity while maintaining optical performance.
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 optical film significantly enhances the brightness and contrast of OLED displays by reducing surface reflectance and optimizing light transmission, outperforming conventional solutions like circular polarizing plates in terms of light-output efficiency and image sharpness.
Implementation Method 1
a light diffusion layer which scatters light incident to a surface of the substrate
Implementation Method 2
a light-absorbing layer which absorbs the light scattered by the light diffusion layer
Data Source
AI summary
The subject invention features a low-reflectivity, brightness-enhancing multilayer optical film for enhancing the brightness of an organic light emission diode (OLED) display and imparting anti-reflection performance to the display.