LED Substrate Asymmetric Amorphous Regions
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Solution Overview
Problem
Current light emitting devices face challenges in achieving high light extraction efficiency and reducing cracks in crystalline substrates during the manufacturing process.
Innovation Solution
A light emitting device structure featuring a crystalline substrate with projections and amorphous regions of varying depths on its side surfaces, combined with a laser scribing method that minimizes overlapping damage to reduce substrate cracking and enhance light extraction by using a stealth laser process to form amorphous regions without overlapping them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional laser scribing is used to divide the substrate, then the substrate can be processed, but cracks occur in the crystalline substrate due to overlapping amorphous regions
Solution Approach 1:
The patent applies asymmetry by making the amorphous region depths asymmetric across different side surfaces of the substrate. Specifically, the first side surface has an amorphous region at a first depth, while the second side surface has an amorphous region at a second depth that is different from the first depth. This asymmetric design ensures that when laser beams intersect to form amorphous regions, the regions do not overlap, thereby preventing crack formation while maintaining effective substrate division and processing capability.
2Strength
If the substrate thickness is increased to improve mechanical strength, then crack resistance improves, but light extraction efficiency decreases
Solution Approach 1:
The patent applies local quality by creating localized amorphous regions with different depths at specific side surfaces of the substrate. Instead of uniformly treating the entire substrate, the invention selectively modifies local regions through laser irradiation to create amorphous zones that enhance light extraction efficiency at the boundaries where it matters most, while preserving the overall substrate thickness and mechanical strength.
Solution Approach 2:
The patent addresses the thickness-efficiency tradeoff by introducing a depth dimension variation in the amorphous regions. By controlling the depth of amorphous regions differently at different side surfaces (first depth vs. second depth), the invention creates a three-dimensional structural variation that enhances light extraction without requiring a reduction in overall substrate thickness, thus maintaining mechanical strength while improving optical performance.
3Device complexity
If amorphous regions are formed at the same depth on all side surfaces, then the process is simple, but overlapping amorphous regions cause substrate damage
Solution Approach 1:
The patent resolves the contradiction between process simplicity and substrate damage prevention by introducing asymmetric amorphous region depths. Rather than using a simple uniform depth approach that causes overlapping damage, the invention employs different depths (first depth on first side surface, second depth on second side surface) that are specifically designed to prevent overlap. This asymmetric configuration adds some complexity to the process parameters but eliminates the harmful overlapping effect, achieving substrate integrity.
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 light extraction efficiency and reduces substrate cracking, allowing for the use of thicker substrates and increased lateral light emission, resulting in a more efficient light emitting device with improved manufacturing processes.
Implementation Method 1
a first laser beam is irradiated onto a first side surface of the substrate along a first direction to form a first amorphous region in the substrate
Implementation Method 2
form a first amorphous region in the substrate
Implementation Method 3
a light emitting structure layer comprising a first conductive type semiconductor layer, an active layer, and a second conductive type semiconductor layer on the crystalline substrate
Data Source
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AI summary
Provided are a light emitting diode, a light emitting diode package, and a lighting system. The light emitting diode includes a crystalline substrate (10) having a plurality of side surfaces (11-14), a light emitting structure layer comprising a first conductive type semiconductor layer, an active layer, and a second conductive type semiconductor layer on the substrate, and a first electrode on the first conductive type semiconductor layer and a second electrode on the second conductive type semiconductor layer. An amorphous region (11a,12a) is defined in a side surface of the substrate, and the amorphous regions of two sides (11,12) adjacent to each other have different depths from a top surface of the substrate.