Uneven Metal Layer Reflects Micro LED Side Light
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Solution Overview
Problem
Micro LED displays face challenges in achieving high light extraction efficiency due to light emission from side and bottom surfaces, which is not effectively utilized in current display technologies.
Innovation Solution
The display device incorporates a substrate with an interlayer insulating layer and a metal layer that includes depressed or projection portions to reflect light emitted from the side surfaces of micro LEDs, improving light extraction efficiency by directing it towards the display surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a flat metal layer is used under the light emitting element, then the manufacturing process is simple, but light emitted from side and bottom surfaces is not effectively utilized
Solution Approach 1:
The metal layer is designed with an uneven surface containing multiple protrusions and recesses instead of a flat surface. This curved/uneven topology enables light emitted from side and bottom surfaces of the micro LED to be reflected at various angles toward the display surface, converting previously wasted light into useful output and improving overall light extraction efficiency.
Solution Approach 2:
The invention transitions from a two-dimensional flat metal layer to a three-dimensional uneven surface structure. By adding vertical dimensionality through protrusions and recesses, the metal layer can interact with light from multiple directions (side and bottom surfaces) and redirect it effectively toward the display surface, utilizing light that would otherwise be lost.
2Loss of energy
If an uneven reflective layer is provided to improve light extraction efficiency, then light emission from side and bottom surfaces is utilized, but additional processing steps are required
Solution Approach 1:
The formation of the uneven metal layer is merged with the existing planarization process. The interlayer insulating layer is formed with an uneven surface that directly defines the metal layer's topography, eliminating the need for separate steps to create the uneven reflective structure. This integration maintains manufacturing simplicity while achieving improved light extraction efficiency.
Solution Approach 2:
The uneven surface structure is prepared in advance during the formation of the interlayer insulating layer, before the metal layer is deposited. This preliminary action ensures that when the metal layer is formed, it naturally acquires the uneven topography needed for light reflection, avoiding additional processing steps that would be required if the uneven structure were created afterward.
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
This configuration enhances light emission efficiency from the display surface, improving brightness and contrast while maintaining cost-effectiveness by forming the metal layer without additional processing steps.
Implementation Method 1
a metal layer over the interlayer insulating layer... In the second region, a plurality of second depressed portions is provided along the plurality of first depressed portions
Data Source
AI summary
A display device includes a substrate, an interlayer insulating layer over the substrate, a metal layer over the interlayer insulating layer, and a light emitting element over the metal layer. The interlayer insulating layer includes a plurality of a first depressed portions. The metal layer includes a first region bonding to the light emitting element and a second region surrounding the first region. The second region, a plurality of second depressed portions is provided along the plurality of first depressed portions.