Light Source Encapsulation with Segmented Sulfur Zones
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Solution Overview
Problem
The use of quantum dot materials with sulfur-based dispersants in light emitting devices can lead to sulfidation of metallic materials, causing discoloration and variations in electrical characteristics, particularly with silver-containing components.
Innovation Solution
A layered encapsulation structure is implemented in the light source, where a sulfur-free first region covers the light emitting unit, and a second region with a controlled sulfur content is used for light converting elements, minimizing the reaction between sulfur and metallic materials, and potentially including zinc for improved conversion efficiency and light uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfur-based dispersants are used to improve quantum dot material reliability, then the reliability of quantum dot materials is improved, but sulfidation of metallic materials occurs causing discoloration and electrical characteristic variations
Solution Approach 1:
The encapsulation layer is divided into multiple regions with different sulfur content distributions. The first region (from 0 to 0.01h) has low sulfur content to protect metallic materials, while the second region (from 0.01h to 0.5h) has higher sulfur content to ensure quantum dot material reliability. This spatial segmentation resolves the contradiction by localizing sulfur in different zones.
Solution Approach 2:
Different regions of the encapsulation layer are assigned different sulfur content characteristics. The first region near the light emitting unit has controlled low sulfur content to prevent sulfidation, while the second region has sufficient sulfur content for quantum dot stability. This local quality differentiation allows each zone to fulfill its specific function without compromising the other.
2Stability of the object's composition
If sulfur content in encapsulation layer is increased to ensure quantum dot material stability, then quantum dot material stability is improved, but discoloration of metallic materials occurs
Solution Approach 1:
The encapsulation layer is segmented into a first region with low sulfur content (0 to 0.01h) and a second region with higher sulfur content (0.01h to 0.5h). This segmentation allows quantum dot materials in the second region to have sufficient sulfur for stability while metallic materials in the first region are protected from sulfidation-induced discoloration.
Solution Approach 2:
The first region of the encapsulation layer acts as an intermediary barrier between the sulfur-containing quantum dot materials and the metallic materials. This intermediate zone with controlled low sulfur content prevents direct sulfur-metallic material interaction that causes discoloration, while still allowing the second region to provide sufficient sulfur for quantum dot stability.
3Power
If sulfur content in encapsulation layer is increased to improve quantum dot material performance, then light conversion efficiency is improved, but electrical characteristics of metallic materials vary
Solution Approach 1:
The encapsulation layer is divided into regions with different sulfur content: the first region (0 to 0.01h) has low sulfur content to protect metallic materials and maintain their electrical characteristics, while the second region (0.01h to 0.5h) has higher sulfur content to ensure light conversion efficiency of quantum dot materials.
4Ease of manufacture
If uniform sulfur distribution is used in encapsulation layer, then manufacturing simplicity is maintained, but both sulfidation prevention and quantum dot stability cannot be simultaneously achieved
Solution Approach 1:
The encapsulation layer is designed with non-uniform sulfur distribution, where the first region (0 to 0.01h) has low sulfur content and the second region (0.01h to 0.5h) has higher sulfur content. This local quality differentiation enables simultaneous protection of metallic materials from sulfidation and quantum dot materials for stability, overcoming the limitation of uniform sulfur distribution.
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 approach effectively prevents sulfidation-related issues such as discoloration and resistivity changes, while enhancing light conversion efficiency and uniformity by isolating the light emitting unit from sulfur and allowing controlled color gamut management.
Implementation Method 1
The light converting elements are capable of converting the light emitted from the light emitting devices into white color
Data Source
AI summary
A display includes a light source, wherein the light source includes a base plate, a light emitting unit, and an encapsulation layer. The light emitting unit is disposed on the base plate and has a first top surface. The encapsulation layer covers the light emitting unit and has a second top surface and plural light converting elements, wherein the first top surface is located between the second top surface and the base plate. The encapsulation layer includes a first region, a second region, and a third region from the first top surface to the second top surface, wherein a first sulfur content of the first region is less than a second sulfur content of the second region, and the first sulfur content of the first region is less than a third sulfur content of the third region.