Inversely Tapered Reflective Barrier for OLED Light Extraction
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Solution Overview
Problem
Organic light emitting diode (OLED) display devices suffer from low light extraction efficiency, resulting in significant light loss and increased power consumption when attempting to enhance brightness, which also reduces the device's lifespan.
Innovation Solution
Incorporating a reflective barrier with inversely tapered side surfaces along the edges of subpixels in the OLED display device to improve light extraction efficiency and minimize light leakage by redirecting light that would otherwise be trapped or lost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If more current is applied 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 light that would otherwise be lost or trapped into a beneficial effect by using a reflective barrier to redirect this light toward the emission region. The reflective barrier captures light that would be wasted and redirects it to contribute to the displayed image, thereby improving light extraction efficiency without requiring increased current or power consumption
Solution Approach 2:
The patent changes the optical parameters of the device by introducing a reflective barrier with specific reflectivity characteristics. This structural modification alters the light propagation paths and extraction efficiency, enabling more light to be directed toward the emission region without changing the electrical operating parameters such as current
2Illumination intensity
If more current is applied to increase brightness, then brightness is improved, but lifetime is reduced
Solution Approach 1:
The reflective barrier converts previously lost light into useful light output, improving light extraction efficiency. This allows the device to achieve the same brightness with lower current, thereby reducing stress on the organic light emitting layer and extending device lifetime
3Illumination intensity
If light is emitted from organic light emitting layer, then light output is generated, but most light is lost and extraction efficiency is low
Solution Approach 1:
The reflective barrier captures light that would otherwise be lost or trapped within the device structure and redirects it toward the emission region. This converts energy loss into useful light output, significantly improving light extraction efficiency
Solution Approach 2:
The reflective barrier introduces a new spatial dimension for light management by creating reflected light paths that differ from direct emission paths. This additional optical dimension allows light to be redirected and extracted more efficiently from regions where it would otherwise be trapped
4Loss of energy
If reflective barrier is added to improve light extraction, then light extraction efficiency is improved, but device complexity increases
Solution Approach 1:
The reflective barrier serves multiple functions simultaneously: it reflects light to improve extraction efficiency, defines subpixel boundaries to prevent light leakage, and can be integrated with existing device layers. This multi-functionality justifies the added structural element by providing multiple benefits from a single component
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 enhances light extraction efficiency, reduces power consumption, and extends the lifespan of the OLED display device while minimizing light leakage from adjacent subpixels.
Implementation Method 1
a reflective barrier disposed to correspond to the non-emission region and including a reflective side surface
Implementation Method 2
The LED emits light through an organic electroluminescence phenomenon... When the excitons transit from an excited state to a ground state, light is generated and emitted in the form of visible light by the EML 40
Data Source
AI summary
An organic light emitting diode display device includes a substrate having a plurality of subpixels which each have an emission region and a non-emission region defined along an edge of the emission region. A reflective barrier is disposed to correspond to the non-emission region and includes a reflective side surface. An overcoat layer is disposed on an upper portion of the reflective barrier. A light emitting diode includes a first electrode, an organic light emitting layer, and a second electrode, which are sequentially disposed on the overcoat layer. The reflective side surface of the reflective barrier is inversely tapered such that a width thereof is decreased in a traveling direction of light emitted from the organic light emitting layer.