Light Emitting Display Apparatus with Uneven Insulating Layer
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Solution Overview
Problem
Light emitting display apparatuses face issues with low light extraction efficiency due to surface plasmon loss, total reflection, and waveguide loss, which degrade outdoor visibility and contrast ratio, and the use of black materials to improve black luminance can reduce luminance.
Innovation Solution
A light emitting display apparatus with a substrate having a first and second area, an insulating layer with an uneven surface, a black bank, and electrodes configured to reflect light emitted from the light emitting layer, reducing surface plasmon loss and scattering reflectance, and improving light extraction efficiency and outdoor visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If light is emitted from the light emitting layer, then light output is achieved, but surface plasmon loss confines light inside the apparatus degrading extraction efficiency
Solution Approach 1:
The patent introduces an insulating layer with an uneven surface between the light emitting layer and the black bank as an intermediary structure. This uneven surface disrupts the direct interaction between light and the metal surface, reducing surface plasmon loss while maintaining light confinement benefits. The insulating layer acts as a mediator that prevents harmful energy transfer to free electrons.
Solution Approach 2:
The patent creates an uneven surface topology by forming protrusions and recesses on the insulating layer surface. This dimensional change from a flat to a three-dimensional surface modifies light propagation paths and reduces surface plasmon excitation, thereby improving light extraction efficiency without sacrificing confinement.
2Productivity
If the light emitting device is formed to be uneven, then light extraction is improved, but scattering reflectance in off-state increases degrading black luminance
Solution Approach 1:
The patent applies different properties to different regions: the insulating layer has an uneven surface for light extraction enhancement, while the black bank material provides high absorption for off-state performance. This local differentiation allows each component to optimize its function without compromising the other.
Solution Approach 2:
The insulating layer serves as an intermediary between the uneven device structure and the black bank, preventing direct contact that would cause scattering reflectance. It mediates the interaction between light and the black material, allowing the uneven surface to benefit light extraction while the black bank maintains low off-state reflectance.
3Object-generated harmful factors
If an insulating layer formed of black material is disposed on uneven surface, then black luminance is improved, but luminance is lowered
Solution Approach 1:
The black insulating layer is strategically positioned only in specific regions where it improves black luminance without significantly impacting overall emission area. This localized application minimizes the trade-off between black luminance improvement and overall luminance maintenance.
Solution Approach 2:
The patent modifies the optical parameters of the insulating layer by using black material with specific absorption characteristics. This parameter change improves black luminance while the uneven surface geometry compensates for potential luminance reduction through enhanced light extraction pathways.
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, improves outdoor visibility, and maintains or increases luminance by minimizing surface plasmon loss and scattering reflectance, thereby addressing the limitations of existing display apparatuses.
Implementation Method 1
a first electrode between the light emitting layer and the over coating layer to be configured to upwardly reflect light emitted from the light emitting layer
Implementation Method 2
a black bank between the over coating layer and the light emitting device and configured to reduce the degradation of a contrast ratio due to scattered reflection
Data Source
AI summary
A light emitting display apparatus includes a substrate which includes a first area and a second area, an insulating layer on the substrate and having an uneven surface, a first bank on the insulating layer in the second area and formed of a black material, a first electrode on the insulating layer in the first area where the first electrode covers at least a part of a side surface of the first bank, a light emitting layer on the first electrode, and a second electrode on the light emitting layer.