Display Device Light Function Layer for Efficient Light Extraction
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Solution Overview
Problem
High-definition display devices using self-light emitting elements, such as organic EL, suffer from significant light loss due to wave-guiding effects, resulting in inefficient light extraction and increased processing costs and complexity in existing light extraction structures.
Innovation Solution
A display device design featuring a light function layer that controls the diffusion or transparency state of light, positioned between electrodes, allowing light to be dispersed and extracted more effectively, improving light extraction efficiency while reducing processing complexity and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a high refractive index transparent layer with fine concave/convex structure is provided on the light extraction side, then light extraction efficiency is improved, but device complexity and processing steps increase
Solution Approach 1:
The patent extracts the light extraction function from a separate complex structural layer and integrates it into the existing electrode layer by incorporating light scattering particles. This eliminates the need for additional high refractive index transparent layers and fine concave/convex structures, thereby reducing device complexity while maintaining improved light extraction efficiency.
Solution Approach 2:
The patent merges the light extraction function with the electrode layer by dispersing light scattering particles within the electrode material. This combination allows the electrode to simultaneously perform its electrical function and light extraction function, reducing the total number of layers and simplifying the overall device structure compared to separate light extraction structures.
2Loss of energy
If a high refractive index transparent layer with fine concave/convex structure is provided on the light extraction side, then light extraction efficiency is improved, but manufacturing costs increase
Solution Approach 1:
The patent removes the need for complex additional layers and fine structure formation processes by integrating light extraction functionality into the electrode layer through particle dispersion. This eliminates expensive multi-step fabrication processes required for creating high refractive index layers and fine concave/convex structures, thereby reducing manufacturing costs.
Solution Approach 2:
The patent changes the approach from creating complex geometric structures (fine concave/convex patterns) to a simpler parameter-based solution using light scattering particles with specific refractive indices and size distributions. This parameter change enables light extraction improvement through a more manufacturable process that does not require complex lithography or etching steps.
3Illumination intensity
If light is wave-guided through layers, then light reaches the observer, but most light is lost and cannot be used effectively
Solution Approach 1:
The patent converts the harmful wave-guiding effect that causes light loss into a beneficial effect by introducing light scattering particles. These particles scatter the wave-guided light at the electrode-substrate interface, redirecting it toward the observer and converting previously lost light into useful output, thereby improving overall light extraction efficiency.
4Loss of energy
If light is extracted to adjacent pixels, then trapped light is utilized, but leaking light occurs reducing display quality
Solution Approach 1:
The patent applies local quality by concentrating light scattering particles specifically within the electrode layer at the light extraction interface. This localized application of light scattering creates strong light extraction at the intended location while maintaining pixel boundaries, preventing light from leaking into adjacent pixels and preserving display quality.
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 design enhances light extraction efficiency, reduces processing complexity, and lowers manufacturing costs by dispersing light output from the light emitting layer in a perpendicular direction, improving the overall brightness and aperture ratio of the display device.
Implementation Method 1
a light function layer controlling the diffusion state or transparency state of light and being provided on the same side the light emitting layer with respect to the second electrode
Data Source
AI summary
A display device including a plurality of pixels includes a first display part including a first electrode, a second electrode and a light emitting layer provided between the first electrode and the second electrode, and a second display part including the second electrode, a third electrode and a light function layer provided between the second electrode and the third electrode, the light function layer controlling the diffusion state or transparency state of light and being provided on the same side the light emitting layer with respect to the second electrode.