Light Guiding Scattering Layer for Organic EL Brightness
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Solution Overview
Problem
Organic electroluminescence (EL) display apparatuses face inefficiencies in light extraction due to isotropic light travel within organic layers, leading to insufficient brightness and increased power consumption, as well as reduced lifetime from high current density.
Innovation Solution
Incorporating a light guiding/scattering layer and reflection partition walls to scatter and reflect light emitted from organic EL elements, enhancing light extraction efficiency while preventing color mixing between pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If current density is increased to increase brightness, then brightness is improved, but power consumption increases and lifetime is reduced
Solution Approach 1:
The patent converts the harmful effect of isotropic light travel (which causes light loss) into a beneficial effect by introducing a light guiding/scattering layer that redirects lost light into useful viewing directions, thereby improving brightness without increasing power consumption
Solution Approach 2:
The patent changes the optical parameters of the display structure by adding layers with specific refractive indices and scattering properties, transforming the light extraction efficiency parameter to achieve higher brightness at lower current density
2Illumination intensity
If current density is increased to increase brightness, then brightness is improved, but lifetime is reduced
Solution Approach 1:
The patent converts the harmful effect of isotropic light travel into a beneficial light extraction mechanism, reducing the need for high current density operation and thereby extending the lifetime of the organic EL elements
Solution Approach 2:
By changing the optical extraction efficiency through added functional layers, the operating conditions can be relaxed to lower current densities, which directly extends the operational lifetime of the light-emitting elements
3Object-generated harmful factors
If light is emitted isotropically in organic layers, then light emission is achieved, but light extraction efficiency is insufficient
Solution Approach 1:
The patent introduces a light guiding/scattering layer as an intermediary between the organic EL elements and the viewing environment, which mediates the isotropic light emission and transforms it into directed light extraction with improved efficiency
Solution Approach 2:
The patent employs composite structures combining organic EL elements with inorganic or organic scattering layers having specific refractive index properties, creating a composite optical system that enhances light extraction from isotropic emission
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 increases light extraction efficiency, reduces power consumption, and prolongs the lifetime of organic EL elements by scattering light and minimizing color mixing, allowing for lower current density operation.
Implementation Method 1
a light guiding/scattering layer that is provided on the plurality of light-emitting elements and scatters light emitted from the plurality of light-emitting elements
Implementation Method 2
a reflection partition wall that separates portions of the light guiding/scattering layer corresponding to each of the pixels and reflects the light emitted from the plurality of light-emitting elements
Data Source
AI summary
There is provided a display apparatus that includes a plurality of light-emitting elements that constitutes pixels, a light guiding/scattering layer that is provided on the plurality of light-emitting elements and scatters light emitted from the plurality of light-emitting elements, and a reflection partition wall that separates portions of the light guiding/scattering layer corresponding to each of the pixels and reflects the light emitted from the plurality of light-emitting elements.