Wavelength Converting Layer Thermal Management
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Solution Overview
Problem
Current semiconductor light emitting devices, such as LEDs, face challenges with high thermal resistance due to the thermal conductivity limitations of traditional phosphor/silicone materials, which restrict their ability to handle high power densities effectively.
Innovation Solution
A wavelength converting layer composed of a mixture of wavelength converting material, transparent material, and adhesive material is formed over the light emitting devices, with a high particle content and high thermal conductivity, improving thermal performance by encapsulating the devices on all sides and reducing thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional phosphor/silicone materials are used in the wavelength converting layer, then the device structure is simple and easy to manufacture, but the thermal conductivity is low resulting in high thermal resistance
Solution Approach 1:
The patent applies composite materials by combining wavelength converting particles (phosphor) with transparent adhesive material to form a wavelength converting layer. This composite structure maintains ease of manufacture while improving thermal conductivity, as the adhesive material provides better thermal pathways compared to traditional silicone-based phosphor materials. The composite layer encapsulates the light emitting device on all sides, facilitating heat dissipation.
2Temperature
If the wavelength converting layer encapsulates the light emitting device on all sides, then thermal conductivity is improved, but the adhesive material content must be controlled to maintain structural integrity
Solution Approach 1:
The patent applies parameter changes by precisely controlling the adhesive material content to be between 5-15% by weight of the wavelength converting layer. This parameter optimization ensures sufficient adhesive to maintain structural integrity and encapsulation while minimizing thermal resistance. The controlled adhesive content provides just enough binding to hold the wavelength converting particles in place without creating excessive thermal barriers.
3Temperature
If high particle content is used in the wavelength converting layer, then thermal performance is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by creating a wavelength converting layer with non-uniform particle distribution characteristics. The layer has high particle content (85-95% by weight) optimized for thermal performance in the bulk region, while the adhesive material (5-15% by weight) provides localized binding at particle interfaces and at the boundaries where structural integrity is most critical. This local differentiation of material properties allows high thermal performance without proportionally increasing manufacturing precision requirements.
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 enhances the thermal conductivity of the light emitting devices, enabling them to handle higher power densities and improve reliability by reducing thermal resistance, compared to traditional 'goop in cup' architectures.
Implementation Method 1
The wavelength converting layer absorbs light emitted by the light emitting device and emits light having a second peak wavelength
Implementation Method 2
The solution significantly enhances the thermal conductivity of the light emitting devices, enabling them to handle higher power densities and improve reliability by reducing thermal resistance
Data Source
AI summary
A structure according to embodiments of the invention includes a light emitting device for emitting light having a first peak wavelength. A wavelength converting layer is disposed in a path of light emitted by the light emitting device. The wavelength converting layer absorbs light emitted by the light emitting device and emits light having a second peak wavelength. The wavelength converting layer includes a mixture of a wavelength converting material, a transparent material, and an adhesive material, wherein the adhesive material is no more than 15% of the weight of the wavelength converting layer.