LED Light Engine With Flexible Phosphor Sheath
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Solution Overview
Problem
Conventional LED light engines with phosphor-based white light production suffer from lower efficiency due to heat loss from Stokes shift and lumen degradation caused by phosphor proximity to the LED die, requiring thoughtful thermal design.
Innovation Solution
A flexible silicone sheath impregnated with phosphors is used to convert light from an LED base module with a solid transparent dome, separating the phosphor from the LED die and allowing for improved thermal management and manufacturing flexibility by attaching the sheath to the dome to conform to its shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If phosphor is mixed with the polymer to provide volumetric blue light conversion, then white light emission is achieved, but thermal management becomes difficult due to heat generation from Stokes shift and LED die
Solution Approach 1:
The invention separates the phosphor conversion function from the LED die by using a distinct phosphor layer or phosphor-coated component. This segmentation allows the phosphor to be positioned away from the heat-generating LED die, improving thermal management while maintaining white light emission capability.
Solution Approach 2:
The patent introduces an intermediary component (such as a phosphor-coated lens or separate phosphor layer) that mediates between the LED die and the final light output. This intermediary converts the blue light at a location optimized for thermal performance rather than being directly coupled to the heat-generating die.
2Use of energy by moving object
If phosphor is placed close to the LED die for efficient light conversion, then light conversion efficiency is improved, but lumen degradation occurs due to heat exposure
Solution Approach 1:
The invention divides the system into separate functional zones: the LED die for light generation and the phosphor layer for wavelength conversion. This spatial segmentation allows optimization of each component's position - the phosphor can be placed where it receives adequate light while being protected from excessive heat exposure that causes lumen degradation.
Solution Approach 2:
The patent utilizes the third dimension (z-axis) to position the phosphor at an optimal distance from the LED die. By adjusting the vertical separation distance, the design achieves a balance between receiving sufficient blue light for conversion while being far enough to avoid thermal damage that causes lumen degradation.
3Ease of manufacture
If a fixed phosphor configuration is used in the LED optic, then manufacturing is simplified, but manufacturing flexibility is reduced
Solution Approach 1:
The invention separates the phosphor application into a distinct, removable component that can be independently manufactured and applied. This allows the base LED optic to be manufactured once and reused, while different phosphor configurations can be applied to create different color outputs, thereby improving manufacturing flexibility without significantly complicating the overall process.
Solution Approach 2:
The patent designs the LED optic with a universal base structure that can accommodate multiple phosphor configurations. This universal base module can be used across different product variants, while the phosphor layer serves as the variable component that determines the specific color output, achieving both manufacturing simplicity and flexibility.
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 design enhances thermal efficiency and manufacturing flexibility by reducing heat impact on the phosphor and allowing for interchangeable sheaths to produce various colors, improving LED light engine performance and manufacturing efficiency.
Implementation Method 1
A phosphor that converts the blue light to yellow light (for example, a YAG:Ce phosphor) may be mixed with the polymer to provide volumetric blue light conversion
Implementation Method 2
a blue LED is embedded in or covered with a lens or case (the LED optic)
Data Source
AI summary
A light emitting diode (LED) light engine includes a solid transparent dome mounted on one or more LED dies to form a base module, a flexible sheath having embedded therein a phosphor that converts light of a first wavelength range to light of a second wavelength range, the sheath being attached to the base module so that the sheath conforms to a light emitting surface of the dome. The sheath emits light of the second wavelength range when the LED is emitting light of the first wavelength range. Further sheaths may be formed each with different phosphors or phosphor blends, and one of the sheaths may be selected to cover the base module depending on the color of light to be produced by the light engine.