UV LED Package Sloped Submount Light Extraction
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Solution Overview
Problem
Ultraviolet light emitting device packages have low light extraction efficiency compared to visible light emitting devices, which limits their effectiveness in applications such as sterilizing and disinfecting.
Innovation Solution
A light emitting device package design featuring a submount with a central region and sloped base regions, where reflective layers are strategically positioned to enhance light extraction efficiency, and a submount that dissipates heat generated by the light emitting device chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional flat submount structure is used, then the device structure is simple, but the light extraction efficiency is low
Solution Approach 1:
The submount incorporates a sloped region with a specific angle (e.g., 45 degrees) between its first and second regions. This curved/angled surface design enables light emitted from the light emitting device chip to be reflected at different angles, increasing the probability of light extraction and improving overall light extraction efficiency while maintaining manufacturing feasibility through standard semiconductor fabrication processes.
Solution Approach 2:
The submount transitions from a conventional two-dimensional flat structure to a three-dimensional structure with distinct regions (first region, second region, and sloped region) at different heights and angles. This dimensional change creates multiple light extraction paths and angles, significantly improving light extraction efficiency for ultraviolet light emitting devices.
2Loss of energy
If reflective layers are added to enhance light extraction, then light extraction efficiency improves, but device complexity increases
Solution Approach 1:
The patent integrates the reflective function directly into the submount structure itself rather than adding separate reflective components. The submount's sloped geometry acts as an intrinsic reflector, merging the structural support function with the light extraction enhancement function, thereby improving light extraction efficiency without proportionally increasing device complexity.
Solution Approach 2:
The submount serves multiple functions simultaneously: it provides mechanical support for the light emitting device chip, acts as a heat dissipation pathway, and functions as a reflective structure to enhance light extraction. This multi-functionality reduces the need for additional separate components, balancing improved light extraction efficiency with controlled device complexity.
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 design significantly increases light extraction efficiency and heat dissipation, improving the performance of ultraviolet light emitting device packages in various applications.
Implementation Method 1
A first reflective layer is disposed on the first electrode layer. The first reflective layer overlaps the sloped region. A second reflective layer is disposed on the second electrode layer. The second reflective layer overlaps the sloped region.
Implementation Method 2
a submount that dissipates heat generated by the light emitting device chip
Data Source
AI summary
A light emitting device package includes a package substrate and a submount on the package substrate. An upper surface of the submount includes a central region, first and second base regions spaced from the package substrate, relative to the central region, and a sloped region between the central region and the first and second base regions. A light emitting device chip is in the central region. A first electrode layer is between the central region and the light emitting device chip and extends onto the sloped region and the first base region. A second electrode layer is between the central region and the light emitting device chip, extends onto the sloped region and the second base region, and is spaced apart from the first electrode layer. First and second reflective layers are on the first and second electrode layers, respectively, and overlap the sloped region.