Solid State Lighting Device With Spaced Luminescent Element
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Solution Overview
Problem
Conventional LED packages face energy loss due to backscattering of excitation light from phosphors, self-absorption, and unwanted scattering from large luminescent material particles, which reduces efficiency and performance.
Innovation Solution
Spatially separating the solid state light emitter from the luminescent element, with the luminescent element's surface area being at least twice as large as the emitter's illumination surface, and maintaining a specific distance between them to minimize reabsorption and optimize light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the luminescent material is placed close to the solid state light emitter to maximize light conversion, then the light conversion efficiency is improved, but backscattering of excitation light increases causing energy loss
Solution Approach 1:
The patent divides the luminescent element into multiple particles distributed within the encapsulant rather than using a single solid block. This segmentation allows the excitation light to interact with smaller particles, reducing the probability of backscattering while maintaining effective light conversion. The particles are spaced apart, creating multiple discrete interaction points that minimize harmful backscatter effects.
Solution Approach 2:
The patent creates different local environments by distributing luminescent particles throughout the encapsulant material. Each particle experiences local optical conditions that are optimized for conversion while minimizing backscatter. The encapsulant matrix provides a controlled local environment that manages the interaction between light and luminescent material, allowing efficient conversion without the harmful effects of concentrated luminescent material adjacent to the LED chip.
2Ease of manufacture
If large particles of luminescent material are used to reduce manufacturing complexity, then the manufacturing process is simplified, but unwanted scattering of light increases reducing performance
Solution Approach 1:
The patent segments the luminescent material into particles of controlled size and distribution. While not using the smallest possible particles, the segmentation into multiple smaller particles rather than large blocks maintains manufacturability through conventional mixing and encapsulation processes while significantly improving light extraction by reducing unwanted scattering effects.
Solution Approach 2:
The patent optimizes the particle size parameter of the luminescent material to find a balance between manufacturability and performance. By controlling particle size to be smaller than conventional large particles but not requiring nanoscale precision, the patent achieves improved light extraction efficiency while maintaining ease of manufacture through standard encapsulation techniques.
3Productivity
If the luminescent element surface area is made large to reduce reabsorption, then self-absorption is reduced improving efficiency, but the device size increases
Solution Approach 1:
The patent transitions from a planar or block-like luminescent element to a three-dimensional distribution of particles throughout the encapsulant volume. This dimensional change allows the effective luminescent surface area to be increased without proportionally increasing the device footprint, as the particles are distributed throughout the volume rather than requiring a large planar surface area.
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 configuration enhances light extraction efficiency by reducing backscatter and self-absorption, leading to improved energy efficiency and performance in LED-based lighting devices.
Implementation Method 1
Light emitting diodes are semiconducting devices that emit light (ultraviolet, visible, or infrared) when a potential difference is applied across a p-n junction structure
Implementation Method 2
a luminescent material (e.g., a phosphor) that emits yellow light in response to excitation by light emitted by the light emitting diode
Data Source
Figure 1~2
AI summary
A lighting device comprising at least one solid state light emitter and at least one luminescent element spaced from the light emitter, a surface of the luminescent element being at least twice as large as the illumination surface of the light emitter. Also, a lighting device comprising at least one solid state light emitter and at least one luminescent element spaced from the light emitter, a surface of the luminescent element surface being at least twice as large as and substantially parallel to the illumination surface of the light emitter. Also, a lighting device comprising at least one solid state light emitter and at least one luminescent element spaced from the light emitter, a surface area of a projection of the luminescent element being at least twice as large as a surface area of a projection of the light emitter.