Convex Lens Light Extraction for OLED Top Emission Efficiency
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Solution Overview
Problem
Current OLED display devices face challenges in enhancing light efficiency, particularly for top emission types where light is trapped due to total reflection, leading to reduced luminance and power consumption.
Innovation Solution
Incorporating a convex-shaped lens above the light-emitting element layer, which covers the emission area and is formed using a thermosetting solution via inkjet printing, to refract and extract light more efficiently, and a color filter layer positioned above the encapsulation layer to enhance light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a top emission type OLED structure is used, then light can be discharged toward the opposite side of the substrate, but light extraction efficiency is reduced due to total reflection
Solution Approach 1:
A lens is introduced as an intermediary component between the light-emitting element and the color filter layer. This lens has a refractive index higher than both the encapsulation layer and the color filter layer, creating optical impedance mismatch that enables light extraction. The lens acts as a mediator that converts the total internal reflection condition into effective light emission by providing a controlled refraction interface.
Solution Approach 2:
The patent changes the refractive index parameter by introducing a lens material with a specific refractive index (higher than both the encapsulation layer and color filter layer). This parameter change at the lens interfaces creates the conditions necessary for light extraction by altering the optical path and enabling refraction at the boundaries between layers.
2Illumination intensity
If a lens is placed corresponding to the light-emitting element, then light extraction efficiency is improved, but device structure becomes more complex
Solution Approach 1:
The lens is merged with the encapsulation layer or positioned in close integration with the light-emitting element structure. By combining the lens function with existing structural elements rather than adding a completely separate component, the patent reduces overall device complexity while maintaining the light extraction enhancement.
3Illumination intensity
If the color filter layer is positioned above the encapsulation layer, then light extraction is enhanced, but manufacturing process becomes more complex
Solution Approach 1:
The patent repositions the color filter layer from its conventional position to above the encapsulation layer, utilizing the vertical dimension for optimization. This dimensional rearrangement allows the color filter to be positioned where it can effectively receive and filter the extracted light while maintaining manufacturability through standard layering processes.
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 significantly improves light extraction efficiency by refracting light emitted from the emission layer, thereby increasing luminance and reducing power consumption while maintaining color accuracy.
Implementation Method 1
the lens may be in a convex shape... significantly improves light extraction efficiency by refracting light emitted from the emission layer
Data Source
AI summary
The present disclosure relates to a display device. More particularly, the present disclosure relates to a display device capable of enhancing efficiency of light emitted from a light-emitting element. A display device according to an embodiment includes a substrate on which areas of pixels composed of multiple subpixels are arranged, a circuit element layer in which circuit elements constituting the multiple subpixels are provided, a light-emitting element layer in which light-emitting elements constituting the multiple subpixels are provided, and a lens placed corresponding to the light-emitting element.