Ceramic LED Package Thermal Management via Segmented AlN Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current LED packages inadequately dissipate heat, leading to high temperatures that reduce LED performance, reliability, and lifespan, and cause thermal instability in phosphor-based white light sources, limiting their application in high-power LED devices.
Innovation Solution
The development of LED packages with a thermally conducting layer, such as AlN, and a layered structure that matches the coefficient of thermal expansion of the LED die, along with a metallization pattern for efficient heat dissipation and reduced interfacial stresses, allowing for better thermal conductivity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If current LED package structures are used, then manufacturing is simple, but heat dissipation is inadequate leading to high thermal resistance
Solution Approach 1:
The LED package is divided into multiple functional layers including a thermally conducting layer, a phosphor layer, and a protective encapsulant layer. This segmentation allows each layer to be optimized for its specific function, with the thermally conducting layer dedicated to heat dissipation and the phosphor layer dedicated to light conversion, thereby reducing overall thermal resistance while maintaining manufacturing feasibility through modular assembly
Solution Approach 2:
The package employs composite material structures, specifically combining materials with different thermal conductivities and optical properties in a layered configuration. The thermally conducting layer uses materials with high thermal conductivity to efficiently transport heat away from the LED junction, while the encapsulant provides optical transparency and environmental protection, achieving superior thermal management without excessive structural complexity
2Illumination intensity
If high-power LEDs are used to increase luminosity, then light output increases, but heat generation increases causing thermal instability in phosphors
Solution Approach 1:
A thermally conducting intermediate layer is introduced between the high-power LED junction and the phosphor layer. This intermediary layer acts as a thermal buffer that conducts heat away from the junction before it reaches the phosphor, preventing thermal degradation of the phosphor materials while allowing the high-power LED to operate at elevated currents for increased luminosity output
Solution Approach 2:
The package structure modifies the thermal parameters of the system by introducing layers with specific thermal conductivity values. The thermally conducting layer has high thermal conductivity to rapidly extract heat, while the phosphor layer is positioned at a distance and orientation that minimizes its exposure to thermal stress, thereby maintaining phosphor compositional stability even under high-power operating conditions
3Productivity
If package size is reduced to increase LED density, then more LEDs fit per unit area, but heat dissipation capability is compromised
Solution Approach 1:
The package design transitions from planar heat dissipation to three-dimensional thermal management by implementing vertically stacked layers with distinct thermal functions. The thermally conducting layer is positioned directly beneath the LED junction to provide a vertical heat extraction path, allowing compact horizontal packaging while maintaining effective thermal management through the vertical dimension
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
This solution achieves significant heat dissipation, reducing thermal resistance from 15-20°C/W to 6°C/W, enabling higher luminosity, improved reliability, and compact designs for high-power LEDs, suitable for various applications including high-temperature environments.
Implementation Method 1
LED packages with structures and materials for high heat dissipation... a thermally conducting layer, such as AlN... achieving significant heat dissipation, reducing thermal resistance from 15-20°C/W to 6°C/W
Implementation Method 2
a layered structure that matches the coefficient of thermal expansion of the LED die, along with a metallization pattern for efficient heat dissipation and reduced interfacial stresses
Data Source
AI summary
Methods of forming LED packages and light emitting devices are provided. LED packages and light emitting devices are preferably formed from ceramic layers, such as AlN, though layers of non-ceramic materials can also be used. The layers are formed to include vias, apertures, and metallization layers. The layers are then bonded together to form a panel. The panel is scribed to form a grid of snap lines and then the panel is fractured along the snap lines. To form light emitting devices from the panel, LED dies are added and encapsulated before the panel is fractured.