LED Current Spreading Layer with Recessed Regions for Uniform Diffusion
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Solution Overview
Problem
Existing light-emitting diodes (LEDs) face issues with non-uniform current distribution, high light absorption, and poor heat dissipation due to the limited cross-sectional area and arc-shaped current transmission, leading to high forward voltage and low efficiency.
Innovation Solution
A patterned current spreading layer with defined platform regions and recessed areas, along with a light-transmissive dielectric layer and reflecting layer, to optimize current distribution and reduce light absorption, ensuring uniform current diffusion and enhanced light-emitting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a dot-shaped current transmission block is used, then current can be transmitted from electrode to electrode, but the current transmission direction is arc-shaped which limits current transmission and reduces current per unit time
Solution Approach 1:
The current transmission block is divided into multiple platform regions with recessed regions between them, creating a segmented structure that enables multiple current transmission paths simultaneously, thereby increasing current transmission efficiency without relying on a single arc-shaped path
Solution Approach 2:
The current transmission structure transitions from a two-dimensional dot shape to a three-dimensional patterned structure with platform regions at different heights, enabling current to flow through multiple spatial dimensions and reducing the arc-shaped transmission limitation
2Power
If current flows through a narrow side cross-section of current transmission block, then current can be transmitted, but current and heat cannot be transferred quickly resulting in high forward voltage
Solution Approach 1:
The current transmission block is segmented into multiple platform regions with recessed regions, creating multiple parallel current transmission paths that distribute current and heat across a larger total cross-sectional area, thereby improving heat dissipation efficiency while maintaining high current transmission capacity
Solution Approach 2:
The recessed regions between platform regions create local variations in cross-sectional area, allowing current and heat to be distributed non-uniformly across different regions, optimizing both current transmission capacity and heat dissipation efficiency
3Productivity
If current transmission block has limited side cross-sectional area, then structure remains compact, but current transmitted per unit time is limited
Solution Approach 1:
The current transmission structure utilizes vertical dimension through platform regions at different heights, effectively increasing the total cross-sectional area available for current transmission without significantly increasing the horizontal footprint, thereby achieving high current transmission rate with compact structure
4Loss of energy
If patterned current spreading layer with recessed regions is formed, then light absorption is reduced and light-emitting efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The current spreading layer is segmented into platform regions and recessed regions, where the recessed regions are formed by removing material, thereby reducing light absorption paths and improving light-emitting efficiency while maintaining manufacturability through standard material removal processes
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 achieves uniform current distribution, reduces light absorption, and improves the light-emitting efficiency of LEDs by optimizing the current spreading layer structure.
Implementation Method 1
When current is injected into the electrode at the top of the chip, the current will be transmitted from the electrode to multiple current transmission blocks located in the chip
Implementation Method 2
The light-transmissive dielectric layer is located on a side of the ohmic contact layer facing away from the semiconductor epitaxial stack layer
Implementation Method 3
The reflecting layer is disposed on the light-transmissive dielectric layer, and is filled into the multiple conductive through holes
Implementation Method 4
The ohmic contact layer is located on a side of the multiple platform regions facing away from the second surface
Data Source
AI summary
A light-emitting diode and a light-emitting device are provided. The light-emitting diode defines that a distance between geometric centers of adjacent platform regions in the current spreading layer is equal, that is, a circle is drawn with a geometric center of any platform region as a center and the distance between the geometric centers of adjacent platform regions as a radius, and centers of adjacent platform regions are located on the circle. Thus, the adjacent platform regions form a complementary pattern when current spreads. Taking one platform region as an example, an overlapping area of the current spread between any adjacent platform regions is equal, thereby achieving an effect of uniform current diffusion. In addition, formation of the recessed regions correspondingly reduce a content of the current spreading layer (such as GaP), thereby reducing the light absorption of the current spreading layer and increasing the light-emitting rate of the chip.