Micro-LED Coating Stack for Black Impression and Viewing Angle
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Solution Overview
Problem
Existing Micro-LED displays face issues with white turbidity and reduced black impression due to light scattering materials clumping and the use of adhesive layers with low optical transparency, which also cause mechanical damage and thickness restrictions.
Innovation Solution
A coating layer structure with a black layer structure including transparent layers and a diffusion layer, thermally compressed without adhesive layers, to maintain or improve black impression while enhancing color viewing angle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If light scattering materials are added to the coating layer to improve color viewing angle characteristics, then color viewing angle is improved, but white turbidity phenomenon occurs where light scattering materials clump together and appear white, which degenerates black impression
Solution Approach 1:
The patent applies local quality by creating a multi-layer structure where different layers have different functions: the diffusion layer contains light scattering materials for color viewing angle improvement, while the black layer structure (with or without transparent layers) provides black impression enhancement in specific regions. This spatial differentiation of material properties resolves the contradiction by localizing the light scattering function away from areas where black impression is critical.
Solution Approach 2:
The patent segments the coating layer into multiple functional layers: a diffusion layer with light scattering materials and a black layer structure that may include transparent layers. This segmentation allows the light scattering materials to be confined to specific regions, preventing their clumping from affecting the entire display area, thereby resolving the white turbidity issue while maintaining color viewing angle benefits.
2Object-generated harmful factors
If a black film layer is placed on the coating layer to improve black impression, then black impression is improved, but the black film layer has low adhesiveness requiring a separate adhesive layer such as OCA, which has low optical transparency
Solution Approach 1:
The patent merges the adhesive function and the black layer function into a single integrated structure. The black layer structure is designed to provide both adhesion to the diffusion layer and the desired black impression enhancement, eliminating the need for a separate adhesive layer and reducing overall device complexity while maintaining optical transparency.
Solution Approach 2:
The black layer structure serves multiple functions simultaneously: it provides adhesion to the diffusion layer, enhances black impression, and maintains optical transparency. This multi-functionality eliminates the need for separate adhesive layers and reduces the total number of layers in the device structure.
3Object-generated harmful factors
If a grinding process is performed after the liquid coating layer has cured to improve black impression, then black impression is improved, but the grinding process may cause mechanical damage to the semiconductor light-emitting device, restricting the coating layer thickness
Solution Approach 1:
The patent replaces the mechanical grinding process with a thermal compression process. Instead of mechanically removing material to improve black impression, the invention uses thermal compression to bond the black layer structure to the diffusion layer, achieving the same aesthetic improvement without mechanical damage to the semiconductor light-emitting device and without thickness restrictions.
4Adaptability or versatility
If a coating layer with light scattering materials dispersed therein is provided with certain thickness to secure color viewing angle, then color viewing angle is improved, but the black impression may be deteriorated due to the presence of the coating layer
Solution Approach 1:
The patent segments the coating structure into a diffusion layer with light scattering materials and a separate black layer structure. This segmentation allows the diffusion layer to be optimized for color viewing angle with appropriate thickness, while the black layer structure addresses black impression enhancement without requiring the diffusion layer to be thinner, thus resolving the contradiction between the two optical properties.
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 improves color viewing angle and maintains black impression by reducing scattering material distribution and increasing frontal luminance through refraction at layer interfaces, eliminating the need for adhesive layers.
Implementation Method 1
increasing frontal luminance through refraction at layer interfaces
Implementation Method 2
a diffusion layer disposed on the semiconductor light-emitting device and including a light scattering material
Implementation Method 3
a black layer structure disposed on the diffusion layer and including a transparent layer
Data Source
Figure 1
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AI summary
A display device including a semiconductor light-emitting device (110) according to an embodiment may include a wiring substrate (150), a semiconductor light-emitting device (110) disposed on the wiring substrate (150), a diffusion layer (165) disposed on the semiconductor light-emitting device and including a light scattering material, and a fist black layer structure (180) disposed on the diffusion layer (165) and including a transparent layer (182). The first black layer structure including the transparent layer may include one or more transparent layers (182a, 182b) between the plurality of black layers (181a, 181,b, 181c). The first black layer structure (180) including the transparent layer (182) may include a first black layer (181a), a first transparent layer (182a) disposed on the first black layer (181a), and a second black layer (181b) disposed on the first transparent layer (182a). The first black layer structure including the transparent layer may include a second transparent layer (182b) disposed on the second black layer (181b) and a third black layer (181c) disposed on the second transparent layer (182b).