LED Thermal Conduction Path for Phosphor Color Fidelity
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Solution Overview
Problem
Conventional LED devices face efficiency issues due to thermal quenching, where heat generated during operation reduces the color fidelity of white light emission, as the converter material's low thermal conductivity fails to adequately dissipate heat, leading to off-white appearances in electronic devices.
Innovation Solution
The introduction of a conduction material with high thermal conductivity, positioned between the insulating material and the converter material, efficiently conducts heat away from both the LED die and the converter material to a substrate with enhanced thermal conductivity, reducing thermal quenching and maintaining color fidelity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If converter material is deposited on LED die to generate white light, then color emission is improved, but thermal quenching occurs due to low thermal conductivity of converter material
Solution Approach 1:
A conduction material layer with high thermal conductivity is introduced between the LED die and the converter material layer. This intermediary layer serves as a thermal bridge to conduct heat away from the converter material, preventing thermal quenching while maintaining the white light generation function. The conduction material has thermal conductivity greater than 10 W/m·K, preferably greater than 50 W/m·K, to effectively bridge the thermal gap.
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers with different functional properties: the LED die (light generation), conduction material layer (heat dissipation), insulating material layer (electrical isolation), and substrate (structural support). This composite approach allows each layer to optimize its specific function, particularly the conduction material layer which combines high thermal conductivity with appropriate thickness to balance heat removal and optical performance.
2Device complexity
If conventional LED structure is used, then device simplicity is maintained, but color fidelity deteriorates due to heat accumulation
Solution Approach 1:
The conduction material layer acts as a thermal intermediary that can be integrated into existing LED manufacturing processes. It is deposited or formed between the LED die and converter material using standard techniques such as sputtering, evaporation, or screen printing, adding minimal complexity to the overall device structure while significantly improving color fidelity by preventing heat-induced color shifts.
Solution Approach 2:
The patent modifies the thermal conductivity parameter of the LED structure by introducing the conduction material layer. This parameter change transforms the thermal profile of the device, reducing heat accumulation in the converter material layer and thereby maintaining consistent color emission across operating conditions without fundamentally altering the device architecture.
3Ease of manufacture
If converter material directly contacts LED die, then manufacturing simplicity is maintained, but thermal management efficiency deteriorates
Solution Approach 1:
The conduction material layer is integrated into the manufacturing process as an additional deposition step between applying the LED die and the converter material. This intermediary layer, while adding one process step, uses standard semiconductor fabrication techniques that are already part of LED manufacturing, thus maintaining relative manufacturing simplicity while dramatically improving thermal management efficiency.
Solution Approach 2:
The patent creates a composite thermal management structure where the conduction material layer is combined with the existing LED die and converter material layers. This composite approach allows the system to maintain ease of manufacture through standardized layering processes while achieving superior thermal management efficiency by distributing heat across multiple materials with different thermal properties.
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 effectively reduces thermal quenching by efficiently dissipating heat, ensuring consistent white light emission and improved color fidelity in LED devices.
Implementation Method 1
a conduction material with high thermal conductivity, positioned between the insulating material and the converter material, efficiently conducts heat away from both the LED die and the converter material to a substrate with enhanced thermal conductivity
Implementation Method 2
The LED die 4 can include a silicon substrate 12, N-type gallium nitride (GaN) material 14, an indium gallium nitride (InGaN) material 16 (and/or GaN multiple quantum wells), and a P-type GaN material 18 on one another in series. In operation, the InGaN material 16 of the LED die 4 emits a blue light
Implementation Method 3
The LED die 4 emits a blue light that stimulates the converter material 6 to emit a light (e.g., a yellow light) at a desired frequency
Data Source
AI summary
Solid state lighting devices and associated methods of thermal sinking are described below. In one embodiment, a light emitting diode (LED) device includes a heat sink, an LED die thermally coupled to the heat sink, and a phosphor spaced apart from the LED die. The LED device also includes a heat conduction path in direct contact with both the phosphor and the heat sink. The heat conduction path is configured to conduct heat from the phosphor to the heat sink.