Micro-LED Reflecting Layer for Lateral Light Leakage
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Solution Overview
Problem
Micro light emitting diodes (Micro-LEDs) experience reduced luminescence efficiency due to lateral light leakage, which is difficult to mitigate with existing solutions that involve forming a uniform and high-quality reflecting film on the array substrate, leading to light loss and color mixing issues.
Innovation Solution
A micro-LED device with a transparent insulating layer covering its lateral surface and a reflecting layer, such as a nickel-phosphorous alloy or silver layer, formed by electroless plating, which reflects lateral light output and reduces interference with nearby structures and thin film transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a horn mouth structure with metal reflecting layer is disposed on the array substrate to prevent lateral light leakage, then light output is increased, but it is difficult to form a uniform and high quality reflecting film and light loss occurs due to the large distance and passivating layer
Solution Approach 1:
The patent divides the light management function into two parts: the array substrate provides the horn mouth structure for light direction, while the micro-LED device itself carries the reflecting layer. This segmentation allows the reflecting layer to be formed close to the light emitting layer where it is most needed, improving uniformity and reducing light loss through the passivating layer.
Solution Approach 2:
The patent introduces a transparent insulating layer as an intermediary between the light emitting layer and the reflecting layer. This transparent insulating layer allows the reflecting layer to be formed directly on the micro-LED device surface, eliminating the need for a large distance horn mouth structure and reducing light loss while maintaining electrical insulation.
2Illumination intensity
If a horn mouth structure with metal reflecting layer is disposed on the array substrate to prevent lateral light leakage, then light output is increased, but light loss occurs due to the large distance and passivating layer
Solution Approach 1:
The patent extracts the reflecting layer from the array substrate structure and relocates it to the micro-LED device itself. This extraction eliminates the large distance between the reflecting layer and light emitting layer, reducing light loss through the passivating layer and improving overall light output efficiency.
Solution Approach 2:
The patent changes the spatial arrangement by forming the reflecting layer in a different dimension - directly on the lateral surface of the micro-LED device rather than in the array substrate plane. This dimensional change reduces the optical path distance and minimizes light loss.
3Illumination intensity
If a horn mouth structure with metal reflecting layer is disposed on the array substrate to prevent lateral light leakage, then light output is increased, but color mixing occurs when light enters nearby TFT region
Solution Approach 1:
The patent applies preliminary anti-action by forming the reflecting layer directly on the micro-LED device before light can leak laterally. This reflecting layer immediately redirects lateral light back toward the light output direction, preventing it from entering the TFT region and causing color mixing.
Solution Approach 2:
The patent applies local quality by placing the reflecting layer specifically on the lateral surface of the micro-LED device where light leakage occurs. This localized application of the reflecting layer addresses the specific problem of lateral light leakage without affecting other regions, preventing color mixing in the TFT area.
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 effectively increases luminescence efficiency by preventing lateral light leakage and reducing the influence on nearby structures, while simplifying the manufacturing process and reducing costs by forming a uniform and high-quality reflecting layer directly on the micro-LED device.
Implementation Method 1
a reflecting layer on a side of the transparent insulating layer away from the light emitting unit, wherein the transparent insulating layer insulates the light emitting unit from the reflecting layer, and the reflecting layer covers at least the lateral surface of the light emitting layer
Implementation Method 2
a reflecting layer, such as a nickel-phosphorous alloy or silver layer, formed by electroless plating
Implementation Method 3
a transparent insulating layer covering at least the lateral surface of the light emitting layer; the transparent insulating layer insulates the light emitting unit from the reflecting layer
Data Source
AI summary
Provided is a micro-LED device, comprising: a light emitting unit comprising a light emitting layer having a first end surface, a second end surface opposite to the first end surface, and a lateral surface between the first end surface and the second end surface; a P-type semiconductor layer on the first end surface; and an N-type semiconductor layer on the second end surface; a transparent insulating layer covering at least the lateral surface of the light emitting layer; and a reflecting layer on a side of the transparent insulating layer away from the light emitting unit, wherein the transparent insulating layer insulates the light emitting unit from the reflecting layer, and the reflecting layer covers at least the lateral surface of the light emitting layer.