Horizontal Power LED Device With Embedded Grid Electrode
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Solution Overview
Problem
Conventional horizontal LED devices suffer from low current spreading, high current crowding, and small emitting areas, while vertical LED devices have complex processes and low yield, limiting their effectiveness for high-power and large-area applications.
Innovation Solution
A horizontal power LED device is developed with a light-emitting structure featuring a sequentially laminated N-type gallium nitride semiconductor layer, active layer, and P-type gallium nitride semiconductor layer, along with a metal substrate and embedded grid electrode, which minimizes light emission area reduction, maintains n-clad layer thickness, and eliminates current crowding, and does not require a sub-mount or soldering process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional horizontal LED device structure is used, then the manufacturing process is simple, but the current spreading effect is low and current crowding is high
Solution Approach 1:
The device is divided into a first horizontal LED chip and a second horizontal LED chip, with the second chip inverted relative to the first. This segmentation allows current to spread more effectively across the combined structure while maintaining manufacturing simplicity through standardized chip fabrication processes.
Solution Approach 2:
The patent transitions from a single horizontal chip to a three-dimensional stacked configuration where the second chip is inverted and positioned above the first. This dimensional change enables improved current spreading pathways while keeping the manufacturing process relatively simple by utilizing standard chip bonding techniques.
2Reliability
If a flip-chip LED device is used, then light extraction is improved and heat radiation characteristics are excellent, but additional sub-mount and soldering processes are required
Solution Approach 1:
The patent combines the light extraction benefits of flip-chip architecture with the manufacturing simplicity of horizontal LED structures. By stacking two horizontal chips with one inverted, it achieves improved light extraction and heat radiation without requiring separate sub-mounts or complex soldering processes, as the chips are directly bonded to each other.
Solution Approach 2:
The second horizontal LED chip is essentially a copied and inverted version of the first chip. This copying approach allows the device to achieve flip-chip-like performance characteristics while maintaining the same manufacturing process and structure, avoiding the need for additional sub-mounts and soldering.
3Reliability
If a vertical LED device is used, then current spreading effect is high and light emission is uniform, but the manufacturing process is complicated and yield is low
Solution Approach 1:
Instead of creating a vertical LED structure that requires complex etching and bonding processes, the patent inverts one horizontal chip and stacks it on another. This inversion approach achieves vertical-like current spreading and uniform light emission while maintaining the simpler horizontal chip fabrication process, thereby improving manufacturing yield.
4Area of moving object
If the light emission area is increased, then the emitting area per chip is larger, but current crowding effect increases
Solution Approach 1:
The patent segments the total light emission area into two separate horizontal chips stacked vertically. This segmentation allows each chip to maintain manageable current density while the combined structure provides a larger total emitting area. The inverted configuration of the second chip creates additional current pathways that reduce current crowding.
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 enables high-power and high-efficiency LED operation with improved current spreading, reduced light emission area, and enhanced light extraction efficiency, achieving characteristics similar to vertical LED devices without the complexity of vertical LED manufacturing.
Implementation Method 1
When voltage is applied to each of the doped cladding layers through an electrode in accordance with the polarity thereof, the n-doped cladding layer supplies electrons, and the p-doped cladding layer supplies holes. At this time, electric current flows, and simultaneously these electrons and holes are combined in the active layer disposed between the cladding layers, thus emitting light.
Implementation Method 2
a metal substrate and an embedded grid electrode, which minimizes light emission area reduction, maintains n-clad layer thickness, and eliminates current crowding
Implementation Method 3
an embedded grid electrode, which minimizes light emission area reduction, maintains n-clad layer thickness, and eliminates current crowding
Data Source
AI summary
A method of manufacturing a horizontal power LED device includes constructing a light-emitting structure on a substrate, etching the light-emitting structure, fabricating an electrode, forming an insulating film, forming a metal substrate, removing the substrate from the light-emitting structure, and forming an n-pad. A high-power and high-efficiency horizontal LED device is manufactured by the method of manufacturing the same.