LED Die Reflector Layout for Higher Optical Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing LEDs struggle to maximize luminous flux due to limitations in reflectivity and optical efficiency, particularly in the geometry and size of contact regions and reflective elements within the die structure.
Innovation Solution
A die structure featuring a highly reflective metal reflector covering most of the die area, including mesa-bottom regions, and incorporating a Distributed Bragg Reflector (DBR) that extends over most of the die areas, enhancing reflectivity and optical efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact region size at n Vias and e Vias is increased, then the electrical connectivity is improved, but the reflectivity and optical efficiency decrease
Solution Approach 1:
The die structure is segmented into distinct functional regions: contact regions for electrical connectivity and reflective regions for optical efficiency. The contact regions are specifically positioned at the periphery or bottom surfaces, while the majority of the die area is dedicated to reflective elements, creating spatial separation between electrical and optical functions.
Solution Approach 2:
Different regions of the die are assigned different properties: contact regions have high electrical conductivity, while the majority of the die area has high reflectivity. This local differentiation allows each region to optimize its specific function without compromising the other.
2Productivity
If the reflective elements size is increased, then the luminous flux is improved, but the contact region area is reduced
Solution Approach 1:
The reflective elements extend into the vertical dimension, covering the top surface and extending down the sidewalls of the die structure. This three-dimensional reflective geometry allows maximum light reflection without compromising the horizontal contact region area at the base of the die.
Solution Approach 2:
The die structure is segmented into distinct functional regions: contact regions for electrical connectivity and reflective regions for optical efficiency. The contact regions are specifically positioned at the periphery or bottom surfaces, while the majority of the die area is dedicated to reflective elements, creating spatial separation between electrical and optical functions.
3Loss of energy
If the openings size in die geometry is reduced, then the reflectivity is improved, but the manufacturing complexity increases
Solution Approach 1:
The die structure employs composite materials and multi-layer construction, combining semiconductor layers with metallic reflective coatings and dielectric materials. This composite approach enables complex three-dimensional reflective geometries to be manufactured using standard semiconductor fabrication processes like sputtering and chemical vapor deposition.
Solution Approach 2:
The reflective elements are formed as part of the semiconductor device fabrication process itself, using preliminary deposition and patterning steps integrated into the manufacturing flow. This preliminary formation of reflective structures during fabrication simplifies the overall manufacturing process compared to post-fabrication assembly.
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 significantly increases the luminous flux of LEDs by improving reflectivity and optical efficiency, leading to enhanced performance and practical usefulness in automotive and general illumination applications.
Implementation Method 1
a highly reflective metal reflector that covers most of the die area including the mesa-bottom regions
Implementation Method 2
The reflectivity is further enhanced with the incorporation of a DBR that further extends over most of the die areas
Data Source
AI summary
Methods and devices including a die with a plurality of metal reflectors and/or a distributed bragg reflector (DBR) may improve optical efficiency and/or reflectivity of the system. The metal reflectors may be highly reflective and cover most of the die area including at least most of the n-contact areas. The DBR may also cover most of the die areas. Reflectivity may be improved as a result of one or both of these elements. Additionally, a transparent conductive oxide layer may cover the n-contact areas to improve current spreading.