LED Light-Conversion Layer Segmentation for Thermal Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LED-based white light sources suffer from thermal instability and insufficient brightness due to the uniform dispersion of phosphor materials, leading to degradation and increased costs, especially in high-power applications.
Innovation Solution
A method where a high concentration of wave-shifting material, such as phosphor, is deposited only on the top surface of the LED die, leaving the side surfaces free, allowing for controlled temperature management and improved light conversion efficiency, resulting in brighter and more stable light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphor material is uniformly dispersed throughout the LED structure, then light conversion is achieved, but thermal instability and degradation occur due to poor heat management
Solution Approach 1:
The patent segments the phosphor distribution by concentrating it only on the top surface of the LED die rather than uniformly dispersing it throughout the entire LED structure. This segmentation allows the phosphor to be positioned in a specific zone where it can be effectively cooled by the heat sink, resolving the thermal management issue while maintaining light conversion functionality.
Solution Approach 2:
The patent applies local quality by creating a non-uniform distribution of phosphor material - high concentration on the top surface where light conversion is needed, and no phosphor on the side surfaces. This localized approach optimizes both light conversion efficiency and thermal performance by placing phosphor only where it serves its primary function.
2Illumination intensity
If high concentration of phosphor is used to improve brightness, then light conversion efficiency increases, but thermal degradation worsens
Solution Approach 1:
The patent segments the phosphor distribution by concentrating it only on the top surface of the LED die rather than uniformly dispersing it throughout the entire LED structure. This segmentation allows the phosphor to be positioned in a specific zone where it can be effectively cooled by the heat sink, resolving the thermal management issue while maintaining light conversion functionality.
Solution Approach 2:
The heat sink acts as an intermediary thermal management component that directly contacts the LED die and extends to cool the phosphor layer on the top surface. This intermediary structure enables effective heat removal from the high-concentration phosphor region, allowing high brightness operation without thermal degradation.
3Productivity
If phosphor is deposited on all surfaces of LED die, then complete light conversion is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the phosphor deposition process from being applied to all surfaces and limits it only to the top surface of the LED die. This extraction simplifies the manufacturing process by reducing the deposition area while still achieving effective light conversion, as the side surfaces do not require phosphor coating.
Solution Approach 2:
The patent applies local quality by creating a non-uniform distribution of phosphor material - high concentration on the top surface of the LED die, and no phosphor on the side surfaces. This localized approach optimizes both light conversion efficiency and thermal performance by placing phosphor only where it serves its primary function.
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 approach enhances brightness and uniformity while reducing manufacturing costs, providing thermal stability and maintaining phosphor temperature within a lower range, enabling operation at higher currents for improved performance in high-power LEDs.
Implementation Method 1
A phosphor is a luminescent material that, when excited by a light of a certain wavelength, produces a light at a different wavelength, thus modifying the output light of the LED
Implementation Method 2
phosphors can be used as light 'converters' to alter the color of the light produced by an available LED to the desired color
Implementation Method 3
The temperature of the phosphor can be controlled by the heat sink associated with the LED die
Implementation Method 4
thermal management problems worsen with high power LEDs that are increasingly in demand
Data Source
AI summary
A method for making a lighting apparatus includes providing a substrate and disposing a light-emitting diode overlying the substrate. The light-emitting diode has a top surface oriented away from the substrate and a plurality of side surfaces. A light-conversion material is provided that includes a substantially transparent base material and a wave-shifting material dispersed in the base material. The concentration of the wave-shifting material can be at least 30%. In an embodiment, the concentration of the wave-shifting material can be approximately 50% or 70%. A predetermined amount of the light-conversion material is deposited on the top surface of the light-emitting diode while the side surfaces are maintained substantially free of the light-conversion material.