AlN LED Submount Thermal Management
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Solution Overview
Problem
Conventional LED packages face challenges in manufacturing precision, heat dissipation, and efficiency, particularly for high-power LEDs emitting red or red-orange light, due to the use of separate metal reflectors and ceramic substrates that do not efficiently conduct heat, leading to reduced efficiency and lifetime.
Innovation Solution
The development of LED packages with a ceramic submount using aluminum nitride (AlN) for improved thermal management, combined with a conductive current spreading structure and a lens for efficient light emission, which allows for better heat dissipation and increased luminance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a separate metal reflector is used in conventional LED packages, then light reflection is achieved, but manufacturing precision and alignment complexity deteriorate
Solution Approach 1:
The patent combines the reflector and substrate into a single integrated component. The reflective layer is deposited directly onto the substrate surface, eliminating the need for separate metal reflector assembly and alignment. This integration resolves the manufacturing precision issue while maintaining light reflection functionality.
Solution Approach 2:
The substrate serves multiple functions: it provides mechanical support, electrical connection, and light reflection. By making the substrate multi-functional, the patent eliminates the need for a separate dedicated reflector component, thereby simplifying manufacturing and improving alignment precision.
2Strength
If ceramic substrates are used in conventional LED packages, then mechanical robustness is improved, but heat dissipation efficiency deteriorates
Solution Approach 1:
The patent employs a composite structure combining ceramic substrate with metal reflective layer and thermal management materials. This composite approach maintains the mechanical robustness of ceramic while improving heat dissipation through the metal layers and optimized thermal pathways.
Solution Approach 2:
The patent applies different material properties to different regions: the substrate provides mechanical strength, while specific areas incorporate high-thermal-conductivity materials for heat dissipation. This localized optimization allows simultaneous achievement of mechanical robustness and thermal efficiency.
3Power
If conventional LED packages are used for high-power operation, then power handling capability is improved, but operational lifetime deteriorates due to heat retention
Solution Approach 1:
The patent converts the heat generated by high-power operation from a harmful factor into a managed parameter. Through optimized thermal pathways and heat-sinking structures, the heat is efficiently conducted away, allowing high-power operation without compromising lifetime. The heat management system transforms thermal challenge into a controlled aspect of design.
4Manufacturing precision
If multiple manufacturing steps are used to attach metal reflector with adhesive, then reflector alignment is achieved, but manufacturing complexity and expense increase
Solution Approach 1:
The patent merges the reflector attachment process into the substrate fabrication process itself. The reflective layer is formed as an integral part of the substrate structure through deposition techniques, eliminating separate attachment steps and adhesive application processes.
Solution Approach 2:
The reflective layer is prepared and positioned on the substrate during the substrate manufacturing process itself, before final assembly. This preliminary integration of the reflector function into substrate fabrication eliminates subsequent alignment and attachment steps.
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 results in LED packages with enhanced thermal performance, increased luminous flux, and extended operational lifetime, achieving a minimum luminous flux of approximately 90 lumens and improved reliability for LEDs emitting between 600 nm and 650 nm wavelengths.
Implementation Method 1
The development of LED packages with a ceramic submount using aluminum nitride (AlN) for improved thermal management, combined with a conductive current spreading structure and a lens for efficient light emission, which allows for better heat dissipation
Implementation Method 2
Light emitting dies (LED or LEDs) are solid state devices that convert electric energy to light, and generally comprise one or more active layers of semiconductor material sandwiched between oppositely doped layers. When a bias is applied across the doped layers, holes and electrons are injected into the active layer where they recombine to generate light.
Implementation Method 3
The reflective cup may be filled with an encapsulant material containing a wavelength conversion material such as a phosphor. Light emitted by the LED at a first wavelength may be absorbed by the phosphor, which may responsively emit light at a second wavelength.
Data Source
AI summary
LED packages and related methods are provided. The LED packages can include a submount having a top and bottom surface and a plurality of top electrically conductive elements on the top surface of the submount. An LED can be disposed on one of the top electrically conductive elements. The LED can emit a dominant wavelength generally between approximately 600 nm and approximately 650 nm, and more particularly between approximately 610 nm and approximately 630 nm when an electrical signal is applied to the top electrically conductive elements. A bottom thermally conductive element can be provided on the bottom surface and is not in electrical contact with the top electrically conductive elements. A lens can be disposed over the LED. The LED packages can have improved lumen performances, lower thermal resistances, improved efficiencies, and longer operational lifetimes.